Science.gov

Sample records for perinephric tissues ct

  1. Stage T3a renal cell carcinoma: staging accuracy of CT for sinus fat, perinephric fat or renal vein invasion

    PubMed Central

    Sokhi, H K; Mok, W Y

    2015-01-01

    Objective: To study the accuracy of CT for staging T3a (TNM 2009) renal cell carcinoma (RCC). Methods: Unenhanced and nephrographic phase CT studies of 117 patients (male:female = 82:35; age range, 21–86 years) with T1–T3a RCC were independently reviewed by 2 readers. The presence of sinus or perinephric fat, or renal vein invasion and tumour characteristics were noted. Results: Median (range) tumour size was 5.5 (0.9–19.0) cm; and 46 (39%), 16 (14%) and 55 (47%) tumours were pT1, pT2 and pT3a RCC, respectively. The sensitivity/specificity for sinus fat, perinephric fat and renal vein invasion were 71/79%, 83/76% and 59/93% (Reader 1) and 88/71%, 68/72% and 69/91% (Reader 2) with κ = 0.41, 0.43 and 0.61, respectively. Sinus fat invasion was seen in 47/55 (85%) cases with T3a RCC vs 16/55 (29%) and 33/55 (60%) for perinephric fat and renal vein invasion. Tumour necrosis, irregularity of tumour edge and direct tumour contact with perirenal fascia or sinus fat increased the odds of local invasion [odds ratio (OR), 2.5–3.7; p < 0.05; κ = 0.42–0.61]. Stage T3a tumours were centrally located (OR, 3.9; p = 0.0009). Conclusion: Stage T3a RCC was identified with a sensitivity of 59–88% and specificity of 71–93% (κ = 0.41–0.61). Sinus fat invasion was the most common invasive feature. Advances in knowledge: Centrally situated renal tumours with an irregular tumour edge, inseparable from sinus structures or the perirenal fascia and CT features of tumour necrosis should alert the reader to the possibility of Stage T3a RCC (OR, 2.5–3.9). PMID:25410425

  2. Computed tomography findings in bilateral perinephric lymphangiomatosis.

    PubMed

    Hakeem, Aijaz; Gojwari, Tariq A; Reyaz, Sheikh; Rasool, Shubana; Shafi, Hakim; Mufti, Shahida

    2010-01-01

    Perinephric lymphangioma is rare disorder that may be confused with various forms of renal cystic diseases and urinomas. In this disorder a developmental malformation results in failure of developing lymphatic tissue to establish normal communication with the rest of lymphatic system. Once there is restricted drainage of lymphatic fluid the lymphatic channels dilate to form cystic masses that may be unilocular or multilocular and may be seen unilaterally or bilaterally .This condition presents with various signs and symptoms or can be just an incidental finding which in presence of misleading clinical history may be confused with other diseases. CT scan with delayed cuts and USG guided aspiration with biochemical analysis of fluid will help us in arriving to final diagnosis.

  3. Computed tomography findings in bilateral perinephric lymphangiomatosis

    PubMed Central

    Hakeem, Aijaz; Gojwari, Tariq A; Reyaz, Sheikh; Rasool, Shubana; Shafi, Hakim; Mufti, Shahida

    2010-01-01

    Perinephric lymphangioma is rare disorder that may be confused with various forms of renal cystic diseases and urinomas. In this disorder a developmental malformation results in failure of developing lymphatic tissue to establish normal communication with the rest of lymphatic system. Once there is restricted drainage of lymphatic fluid the lymphatic channels dilate to form cystic masses that may be unilocular or multilocular and may be seen unilaterally or bilaterally .This condition presents with various signs and symptoms or can be just an incidental finding which in presence of misleading clinical history may be confused with other diseases. CT scan with delayed cuts and USG guided aspiration with biochemical analysis of fluid will help us in arriving to final diagnosis. PMID:20842254

  4. Effect of perineoplasm perinephric adipose tissues on migration of clear cell renal cell carcinoma cells: a potential role of WNT signaling

    PubMed Central

    Zi, Xiaolin; Lusch, Achim; Blair, Christopher A.; Okhunov, Zhamshid; Yokoyama, Noriko N.; Liu, Shuman; Baker, Molly; Huynh, Victor; Landman, Jaime

    2016-01-01

    To investigate the cellular and molecular interactions between clear-cell renal cell carcinoma (ccRCC) and perinephric adipose tissue (PAT), perineoplasm PAT, PAT away from the neoplasm, renal sinus and subcutaneous adipose tissues were collected at the time of renal surgery for renal masses and conditioned medium (CM) was generated from 62 patients. Perineoplasm PAT CMs from 44 out of 62 (about 71%) of patients with ccRCC or benign renal diseases (e.g. oncocytomas, angiomyolipomas, multicystic kidney, interstitial fibrosis, etc.) enhanced the migration of CaKi-2 cells. Perineoplasm PAT CMs from ccRCC significantly increased migration of ACHN and CaKi-2 cells by ~8.2 and ~2.4 folds, respectively, relative to those from benign renal diseases, whereas there is no significant difference in migration between ccRCC and benign renal diseases in CMs collected from culturing PAT away from neoplasm, renal sinus and subcutaneous adipose tissues. High Fuhrman Grade was associated with increased migration of Caki-2 cells by perineoplasm PAT CMs. Perineoplasm PATs from pT3 RCCs overexpressed multiple WNTs and their CMs exhibited higher WNT/ß-catenin activity and increased the migration of Caki-2 cells compared to CMs from benign neoplasms. Addition of secreted WNT inhibitory factor-1 recombinant protein into perineoplasm PAT CMs completely blocked the cell migration. These results indicate that WNT related factors from perineoplasm PAT may promote progression of local ccRCC to locally advanced (pT3) disease by increasing ccRCC cell mobility. PMID:27409168

  5. CT of soft-tissue neoplasms

    SciTech Connect

    Weekes, R.G.; McLeod, R.A.; Reiman, H.M.; Pritchard, D.J.

    1985-02-01

    The computed tomographic scans (CT) of 84 patients with untreated soft-tissue neoplasms were studied, 75 with primary and nine with secondary lesions. Each scan was evaluated using several criteria: homogeneity and density, presence and type of calcification, presence of bony destruction, involvement of multiple muscle groups, definition of adjacent fat, border definition, and vessel or nerve involvement. CT demonstrated the lesion in all 84 patients and showed excellent anatomic detail in 64 of the 75 patients with primary neoplasms. The CT findings were characteristic enough to suggest the histology of the neoplasm in only 13 lesions (nine lipomas, three hemangiomas, one neurofibroma). No malignant neoplasm had CT characteristics specific enough to differentiate it from any other malignant tumor. However, malignant neoplasms could be differentiated from benign neoplasms in 88% of the cases.

  6. CT volumetry of the skeletal tissues

    SciTech Connect

    Brindle, James M.; Alexandre Trindade, A.; Pichardo, Jose C.; Myers, Scott L.; Shah, Amish P.; Bolch, Wesley E.

    2006-10-15

    Computed tomography (CT) is an important and widely used modality in the diagnosis and treatment of various cancers. In the field of molecular radiotherapy, the use of spongiosa volume (combined tissues of the bone marrow and bone trabeculae) has been suggested as a means to improve the patient-specificity of bone marrow dose estimates. The noninvasive estimation of an organ volume comes with some degree of error or variation from the true organ volume. The present study explores the ability to obtain estimates of spongiosa volume or its surrogate via manual image segmentation. The variation among different segmentation raters was explored and found not to be statistically significant (p value >0.05). Accuracy was assessed by having several raters manually segment a polyvinyl chloride (PVC) pipe with known volumes. Segmentation of the outer region of the PVC pipe resulted in mean percent errors as great as 15% while segmentation of the pipe's inner region resulted in mean percent errors within {approx}5%. Differences between volumes estimated with the high-resolution CT data set (typical of ex vivo skeletal scans) and the low-resolution CT data set (typical of in vivo skeletal scans) were also explored using both patient CT images and a PVC pipe phantom. While a statistically significant difference (p value <0.002) between the high-resolution and low-resolution data sets was observed with excised femoral heads obtained following total hip arthroplasty, the mean difference between high-resolution and low-resolution data sets was found to be only 1.24 and 2.18 cm{sup 3} for spongiosa and cortical bone, respectively. With respect to differences observed with the PVC pipe, the variation between the high-resolution and low-resolution mean percent errors was a high as {approx}20% for the outer region volume estimates and only as high as {approx}6% for the inner region volume estimates. The findings from this study suggest that manual segmentation is a reasonably accurate

  7. Splenectomy and risk of renal and perinephric abscesses

    PubMed Central

    Lai, Shih-Wei; Lin, Hsien-Feng; Lin, Cheng-Li; Liao, Kuan-Fu

    2016-01-01

    Abstract Little epidemiological research is available on the relationship between splenectomy and renal and perinephric abscesses. The purpose of the study was to examine this issue in Taiwan. We conducted a population-based retrospective cohort study using the hospitalization dataset of the Taiwan National Health Insurance Program. A total of 16,426 participants aged 20 and older who were newly diagnosed with splenectomy from 1998 to 2010 were assigned to the splenectomy group, whereas 65,653 sex-matched, age-matched, and comorbidity-matched, randomly selected participants without splenectomy were assigned to the nonsplenectomy group. The incidence of renal and perinephric abscesses at the end of 2011 was measured in both groups. The multivariable Cox proportional hazards regression model was used to measure the hazard ratio (HR) and 95% confidence interval (CI) for risk of renal and perinephric abscesses associated with splenectomy and other comorbidities including cystic kidney disease, diabetes mellitus, urinary tract infection, and urolithiasis. The overall incidence rate of renal and perinephric abscesses was 2.14-fold greater in the splenectomy group than that in the nonsplenectomy group (2.24 per 10,000 person-years vs 1.05 per 10,000 person-years, 95% CI 2.02, 2.28). After controlling for sex, age, cystic kidney disease, diabetes mellitus, urinary tract infection, and urolithiasis, the multivariable regression analysis demonstrated that the adjusted HR of renal and perinephric abscesses was 2.24 for the splenectomy group (95 % CI 1.30, 3.88), when compared with the nonsplenectomy group. In further analysis, the adjusted HR markedly increased to 7.69 for those comorbid with splenectomy and diabetes mellitus (95% CI 3.31, 17.9). Splenectomy is associated with renal and perinephric abscesses, particularly comorbid with diabetes mellitus. In view of its potential morbidity and mortality, clinicians should consider the possibility of renal and perinephric

  8. Fully automated adipose tissue measurement on abdominal CT

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Sussman, Daniel L.; Summers, Ronald M.

    2011-03-01

    Obesity has become widespread in America and has been associated as a risk factor for many illnesses. Adipose tissue (AT) content, especially visceral AT (VAT), is an important indicator for risks of many disorders, including heart disease and diabetes. Measuring adipose tissue (AT) with traditional means is often unreliable and inaccurate. CT provides a means to measure AT accurately and consistently. We present a fully automated method to segment and measure abdominal AT in CT. Our method integrates image preprocessing which attempts to correct for image artifacts and inhomogeneities. We use fuzzy cmeans to cluster AT regions and active contour models to separate subcutaneous and visceral AT. We tested our method on 50 abdominal CT scans and evaluated the correlations between several measurements.

  9. Association of Clinical and Radiographic Features with Perinephric “Sticky” Fat

    PubMed Central

    Qiong, Han; Crispen, Paul L.; Venkatesh, Ramakrishna; Strup, Stephen E.

    2013-01-01

    Abstract Background and Purpose The discovery of thick, adherent, perinephric sticky fat (PSF) is relatively common during open or laparoscopic retroperitoneal surgery. To our knowledge, however, there has been no previous analysis of clinical or radiographic features associated with the development of PSF or of perioperative outcomes for those patients in whom it is found. Our objective is to analyze potential predictive features and determine whether there is any effect on clinical or pathologic outcomes for patients with perinephric sticky fat. Patients and Methods Patients undergoing partial nephrectomy or laparoscopic cryoablation with available preoperative imaging were identified from 2005 to 2011. Operative records were reviewed to identify patients with and without PSF. Preoperative images and medical records were examined to obtain patient data regarding potential predictors as well as clinical and pathologic outcomes. Results A total of 29 patients were identified—16 with PSF and 13 controls. Statistically significant factors associated with PSF included sex, tumor size, presence of perinephric stranding, tumor >50% exophytic, and thickness of perinephric fat (P<0.05). Median total operative time for patients with sticky fat was nearly 40 minutes longer than the control group (228 min vs 190 min, P<0.05). All four (17%) patients with Fuhrman grade 3 or 4 renal-cell carcinoma were from the sticky fat group (P=0.09). Conclusions Despite the small sample size, multiple possible factors associated with perinephric sticky fat were identified and may provide guidance for future investigation of this phenomenon. PMID:22966767

  10. Splenectomy and risk of renal and perinephric abscesses: A population-based cohort study in Taiwan.

    PubMed

    Lai, Shih-Wei; Lin, Hsien-Feng; Lin, Cheng-Li; Liao, Kuan-Fu

    2016-08-01

    Little epidemiological research is available on the relationship between splenectomy and renal and perinephric abscesses. The purpose of the study was to examine this issue in Taiwan.We conducted a population-based retrospective cohort study using the hospitalization dataset of the Taiwan National Health Insurance Program. A total of 16,426 participants aged 20 and older who were newly diagnosed with splenectomy from 1998 to 2010 were assigned to the splenectomy group, whereas 65,653 sex-matched, age-matched, and comorbidity-matched, randomly selected participants without splenectomy were assigned to the nonsplenectomy group. The incidence of renal and perinephric abscesses at the end of 2011 was measured in both groups. The multivariable Cox proportional hazards regression model was used to measure the hazard ratio (HR) and 95% confidence interval (CI) for risk of renal and perinephric abscesses associated with splenectomy and other comorbidities including cystic kidney disease, diabetes mellitus, urinary tract infection, and urolithiasis.The overall incidence rate of renal and perinephric abscesses was 2.14-fold greater in the splenectomy group than that in the nonsplenectomy group (2.24 per 10,000 person-years vs 1.05 per 10,000 person-years, 95% CI 2.02, 2.28). After controlling for sex, age, cystic kidney disease, diabetes mellitus, urinary tract infection, and urolithiasis, the multivariable regression analysis demonstrated that the adjusted HR of renal and perinephric abscesses was 2.24 for the splenectomy group (95 % CI 1.30, 3.88), when compared with the nonsplenectomy group. In further analysis, the adjusted HR markedly increased to 7.69 for those comorbid with splenectomy and diabetes mellitus (95% CI 3.31, 17.9).Splenectomy is associated with renal and perinephric abscesses, particularly comorbid with diabetes mellitus. In view of its potential morbidity and mortality, clinicians should consider the possibility of renal and perinephric abscesses when

  11. Influence of age and position on the CT number of adipose tissues in pigs.

    PubMed

    McEvoy, Fintan J; Madsen, Mads T; Svalastoga, Eiliv L

    2008-10-01

    The location of adipose tissue depots is important in determining their significance. Research into the physical and chemical differences between these depots is therefore of interest. Using image analysis, this paper examines the influence of location on the linear attenuation coefficient of adipose tissue for X-rays, in computed tomography (as indicated by CT number) at three time points. Nine pigs were CT scanned on three separate occasions approximately 1 month apart. The mean CT number was -78, -100, and -104 for visceral adipose tissue (VAT) from the first to the final scan, respectively. The corresponding CT numbers for subcutaneous adipose tissue (SAT) were -80, -101, and -106. There was a significant difference between the CT numbers at each location at each scan (P values from 0.025 to <0.001) and between the CT numbers for each location at different times (P < 0.05). In a separate analysis of the final scan session, the mean CT number of adipose tissue at increasing distances from a mathematically defined center of the animal was determined. Regression analysis showed that the CT number of adipose tissue decreases with increasing distance from the animal's center (y = -102.7 - 0.04 x, P < 0.001, where y is the predicted CT number for adipose tissue, from the animal center (x = 0) to the skin (x = 100)). It can thus be expected that the overall mean CT number for adipose tissue can be used as an indicator of the relative quantities of adipose tissue at each location if the mean for each is known.

  12. Brain tissue segmentation in 4D CT using voxel classification

    NASA Astrophysics Data System (ADS)

    van den Boom, R.; Oei, M. T. H.; Lafebre, S.; Oostveen, L. J.; Meijer, F. J. A.; Steens, S. C. A.; Prokop, M.; van Ginneken, B.; Manniesing, R.

    2012-02-01

    A method is proposed to segment anatomical regions of the brain from 4D computer tomography (CT) patient data. The method consists of a three step voxel classification scheme, each step focusing on structures that are increasingly difficult to segment. The first step classifies air and bone, the second step classifies vessels and the third step classifies white matter, gray matter and cerebrospinal fluid. As features the time averaged intensity value and the temporal intensity change value were used. In each step, a k-Nearest-Neighbor classifier was used to classify the voxels. Training data was obtained by placing regions of interest in reconstructed 3D image data. The method has been applied to ten 4D CT cerebral patient data. A leave-one-out experiment showed consistent and accurate segmentation results.

  13. Comparison of CT-Number and Gray Scale Value of Different Dental Materials and Hard Tissues in CT and CBCT

    PubMed Central

    Emadi, Naghmeh; Safi, Yaser; Akbarzadeh Bagheban, Alireza; Asgary, Saeed

    2014-01-01

    Introduction: Computed tomography (CT) and cone-beam CT (CBCT) are valuable diagnostic aids for many clinical applications. This study was designed to compare the gray scale value (GSV) and Hounsfield unit (HU) of selected dental materials and various hard tissues using CT or CBCT. Methods and Materials: Three samples of all test materials including amalgam (AM), composite resin (CR), glass ionomer (GI), zinc-oxide eugenol (ZOE), calcium-enriched mixture (CEM) cement, AH-26 root canal sealer (AH-26), gutta-percha (GP), Coltosol (Col), Dycal (DL), mineral trioxide aggregate (MTA), zinc phosphate (ZP), and polycarbonate cement (PC) were prepared and scanned together with samples of bone, dentin and enamel using two CBCT devices, Scanora 3D (S3D) and NewTom VGi (NTV) and a spiral CT (SCT) scanner (Somatom Emotion 16 multislice spiral CT);. Subsequently, the HU and GSV values were determined and evaluated. The data were analyzed by the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was determined at 0.05. Results: There were significant differences among the three different scanners (P<0.05). The differences between HU/GSV values of 12 selected dental materials using NTV was significant (P<0.05) and for S3D and SCT was insignificant (P>0.05). All tested materials showed maximum values in S3D and SCT (3094 and 3071, respectively); however, bone and dentin showed low/medium values (P<0.05). In contrast, the tested materials and tissues showed a range of values in NTV (366 to15383; P<0.05). Conclusion: Scanner system can influence the obtained HU/GSV of dental materials. NTV can discriminate various dental materials, in contrast to S3D/SCT scanners. NTV may be a more useful diagnostic aid for clinical practice. PMID:25386210

  14. Perinephric stranding and bulky psoas mimicking pyelonephritis in a case of non-Hodgkin lymphoma of kidney.

    PubMed

    Singh, Shrawan Kumar; Sharma, Aditya Prakash; Mittal, Ankur; Lal, Anupam

    2015-05-01

    A 68-year-old male patient presented with fever and right groin pain. He had leukocytosis with azotemia. Computed tomography revealed enlarged right kidney with thickening and enhancement of walls of pelvicalyceal system and perinephric fat stranding, suggestive of pyelonephritis. Multiple enlarged lymph nodes encased right renal vessels and were present in the retrocaval region. The right psoas muscle was bulky. Fine-needle aspiration cytology and biopsy from the lesions showed features of non-Hodgkin lymphoma. Immunohistochemistry confirmed the diagnosis of diffuse, large, B-cell lymphoma. We emphasize lymphoma in differential diagnosis of atypical renal imaging suggestive of pyelonephritis and perinephritis.

  15. Functional CT imaging of angiogenesis in rabbit VX2 soft-tissue tumour

    NASA Astrophysics Data System (ADS)

    Purdie, Thomas G.; Henderson, Elizabeth; Lee, Ting-Yim

    2001-12-01

    Functional parameters such as blood flow (BF), microvessel permeability surface area product (PS), blood volume (BV) and mean transit time (MTT) are physiological markers related to the changes associated with angiogenesis. In the current study we present a functional CT technique for the simultaneous measurement of these four functional parameters and the display of each parameter as a functional image over an entire tissue slice. New Zealand White rabbits with implanted VX2 thigh tumours were scanned using CT with contrast media injection. The ex vivo method of radioactive microspheres was used to evaluate the accuracy of BF measurements with the functional CT technique. There was a significant linear correlation (R = 0.96) between regional CT and microsphere-measured BF values, with a slope not significantly different from unity (0.98 +/- 0.02, P < 0.0001). The precision of our CT technique was determined by the repeated scanning under steady-state conditions. The precision of CT-measured BF, PS, BV and MTT was 14%, 18%, 20% and 24%, respectively. In conclusion, BF can be measured accurately and BF, PS, BV and MTT reproducibly using our functional CT technique. Functional CT can be readily incorporated into existing imaging protocols to assess tumour angiogenesis.

  16. Automatic Segmentation and Quantification of White and Brown Adipose Tissues from PET/CT Scans.

    PubMed

    Hussein, Sarfaraz; Green, Aileen; Watane, Arjun; Reiter, David; Chen, Xinjian; Papadakis, Georgios Z; Wood, Bradford; Cypess, Aaron; Osman, Medhat; Bagci, Ulas

    2016-12-06

    In this paper, we investigate the automatic detection of white and brown adipose tissues using Positron Emission Tomography/ Computed Tomography (PET/CT) scans, and develop methods for the quantification of these tissues at the whole-body and body-region levels. We propose a patient-specific automatic adiposity analysis system with two modules. In the first module, we detect white adipose tissue (WAT) and its two sub-types from CT scans: Visceral Adipose Tissue (VAT) and Subcutaneous Adipose Tissue (SAT). This process relies conventionally on manual or semi-automated segmentation, leading to inefficient solutions. Our novel framework addresses this challenge by proposing an unsupervised learning method to separate VAT from SAT in the abdominal region for the clinical quantification of central obesity. This step is followed by a context driven label fusion algorithm through sparse 3D Conditional Random Fields (CRF) for volumetric adiposity analysis. In the second module, we automatically detect, segment, and quantify brown adipose tissue (BAT) using PET scans because unlike WAT, BAT is metabolically active. After identifying BAT regions using PET, we perform a co-segmentation procedure utilizing asymmetric complementary information from PET and CT. Finally, we present a new probabilistic distance metric for differentiating BAT from non-BAT regions. Both modules are integrated via an automatic body-region detection unit based on one-shot learning. Experimental evaluations conducted on 151 PET/CT scans achieve state-of-the-art performances in both central obesity as well as brown adiposity quantification.

  17. Quantitative CT imaging for adipose tissue analysis in mouse model of obesity

    NASA Astrophysics Data System (ADS)

    Marchadier, A.; Vidal, C.; Tafani, J.-P.; Ordureau, S.; Lédée, R.; Léger, C.

    2011-03-01

    In obese humans CT imaging is a validated method for follow up studies of adipose tissue distribution and quantification of visceral and subcutaneous fat. Equivalent methods in murine models of obesity are still lacking. Current small animal micro-CT involves long-term X-ray exposure precluding longitudinal studies. We have overcome this limitation by using a human medical CT which allows very fast 3D imaging (2 sec) and minimal radiation exposure. This work presents novel methods fitted to in vivo investigations of mice model of obesity, allowing (i) automated detection of adipose tissue in abdominal regions of interest, (ii) quantification of visceral and subcutaneous fat. For each mouse, 1000 slices (100μm thickness, 160 μm resolution) were acquired in 2 sec using a Toshiba medical CT (135 kV, 400mAs). A Gaussian mixture model of the Hounsfield curve of 2D slices was computed with the Expectation Maximization algorithm. Identification of each Gaussian part allowed the automatic classification of adipose tissue voxels. The abdominal region of interest (umbilical) was automatically detected as the slice showing the highest ratio of the Gaussian proportion between adipose and lean tissues. Segmentation of visceral and subcutaneous fat compartments was achieved with 2D 1/2 level set methods. Our results show that the application of human clinical CT to mice is a promising approach for the study of obesity, allowing valuable comparison between species using the same imaging materials and software analysis.

  18. An open environment CT-US fusion for tissue segmentation during interventional guidance.

    PubMed

    Caskey, Charles F; Hlawitschka, Mario; Qin, Shengping; Mahakian, Lisa M; Cardiff, Robert D; Boone, John M; Ferrara, Katherine W

    2011-01-01

    Therapeutic ultrasound (US) can be noninvasively focused to activate drugs, ablate tumors and deliver drugs beyond the blood brain barrier. However, well-controlled guidance of US therapy requires fusion with a navigational modality, such as magnetic resonance imaging (MRI) or X-ray computed tomography (CT). Here, we developed and validated tissue characterization using a fusion between US and CT. The performance of the CT/US fusion was quantified by the calibration error, target registration error and fiducial registration error. Met-1 tumors in the fat pads of 12 female FVB mice provided a model of developing breast cancer with which to evaluate CT-based tissue segmentation. Hounsfield units (HU) within the tumor and surrounding fat pad were quantified, validated with histology and segmented for parametric analysis (fat: -300 to 0 HU, protein-rich: 1 to 300 HU, and bone: HU>300). Our open source CT/US fusion system differentiated soft tissue, bone and fat with a spatial accuracy of ∼1 mm. Region of interest (ROI) analysis of the tumor and surrounding fat pad using a 1 mm(2) ROI resulted in mean HU of 68±44 within the tumor and -97±52 within the fat pad adjacent to the tumor (p<0.005). The tumor area measured by CT and histology was correlated (r(2) = 0.92), while the area designated as fat decreased with increasing tumor size (r(2) = 0.51). Analysis of CT and histology images of the tumor and surrounding fat pad revealed an average percentage of fat of 65.3% vs. 75.2%, 36.5% vs. 48.4%, and 31.6% vs. 38.5% for tumors <75 mm(3), 75-150 mm(3) and >150 mm(3), respectively. Further, CT mapped bone-soft tissue interfaces near the acoustic beam during real-time imaging. Combined CT/US is a feasible method for guiding interventions by tracking the acoustic focus within a pre-acquired CT image volume and characterizing tissues proximal to and surrounding the acoustic focus.

  19. An Open Environment CT-US Fusion for Tissue Segmentation during Interventional Guidance

    PubMed Central

    Caskey, Charles F.; Hlawitschka, Mario; Qin, Shengping; Mahakian, Lisa M.; Cardiff, Robert D.; Boone, John M.; Ferrara, Katherine W.

    2011-01-01

    Therapeutic ultrasound (US) can be noninvasively focused to activate drugs, ablate tumors and deliver drugs beyond the blood brain barrier. However, well-controlled guidance of US therapy requires fusion with a navigational modality, such as magnetic resonance imaging (MRI) or X-ray computed tomography (CT). Here, we developed and validated tissue characterization using a fusion between US and CT. The performance of the CT/US fusion was quantified by the calibration error, target registration error and fiducial registration error. Met-1 tumors in the fat pads of 12 female FVB mice provided a model of developing breast cancer with which to evaluate CT-based tissue segmentation. Hounsfield units (HU) within the tumor and surrounding fat pad were quantified, validated with histology and segmented for parametric analysis (fat: −300 to 0 HU, protein-rich: 1 to 300 HU, and bone: HU>300). Our open source CT/US fusion system differentiated soft tissue, bone and fat with a spatial accuracy of ∼1 mm. Region of interest (ROI) analysis of the tumor and surrounding fat pad using a 1 mm2 ROI resulted in mean HU of 68±44 within the tumor and −97±52 within the fat pad adjacent to the tumor (p<0.005). The tumor area measured by CT and histology was correlated (r2 = 0.92), while the area designated as fat decreased with increasing tumor size (r2 = 0.51). Analysis of CT and histology images of the tumor and surrounding fat pad revealed an average percentage of fat of 65.3% vs. 75.2%, 36.5% vs. 48.4%, and 31.6% vs. 38.5% for tumors <75 mm3, 75–150 mm3 and >150 mm3, respectively. Further, CT mapped bone-soft tissue interfaces near the acoustic beam during real-time imaging. Combined CT/US is a feasible method for guiding interventions by tracking the acoustic focus within a pre-acquired CT image volume and characterizing tissues proximal to and surrounding the acoustic focus. PMID:22132098

  20. The relevance of MRI for patient modeling in head and neck hyperthermia treatment planning: A comparison of CT and CT-MRI based tissue segmentation on simulated temperature

    SciTech Connect

    Verhaart, René F. Paulides, Margarethus M.; Fortunati, Valerio; Walsum, Theo van; Veenland, Jifke F.; Lugt, Aad van der

    2014-12-15

    Purpose: In current clinical practice, head and neck (H and N) hyperthermia treatment planning (HTP) is solely based on computed tomography (CT) images. Magnetic resonance imaging (MRI) provides superior soft-tissue contrast over CT. The purpose of the authors’ study is to investigate the relevance of using MRI in addition to CT for patient modeling in H and N HTP. Methods: CT and MRI scans were acquired for 11 patients in an immobilization mask. Three observers manually segmented on CT, MRI T1 weighted (MRI-T1w), and MRI T2 weighted (MRI-T2w) images the following thermo-sensitive tissues: cerebrum, cerebellum, brainstem, myelum, sclera, lens, vitreous humor, and the optical nerve. For these tissues that are used for patient modeling in H and N HTP, the interobserver variation of manual tissue segmentation in CT and MRI was quantified with the mean surface distance (MSD). Next, the authors compared the impact of CT and CT and MRI based patient models on the predicted temperatures. For each tissue, the modality was selected that led to the lowest observer variation and inserted this in the combined CT and MRI based patient model (CT and MRI), after a deformable image registration. In addition, a patient model with a detailed segmentation of brain tissues (including white matter, gray matter, and cerebrospinal fluid) was created (CT and MRI{sub db}). To quantify the relevance of MRI based segmentation for H and N HTP, the authors compared the predicted maximum temperatures in the segmented tissues (T{sub max}) and the corresponding specific absorption rate (SAR) of the patient models based on (1) CT, (2) CT and MRI, and (3) CT and MRI{sub db}. Results: In MRI, a similar or reduced interobserver variation was found compared to CT (maximum of median MSD in CT: 0.93 mm, MRI-T1w: 0.72 mm, MRI-T2w: 0.66 mm). Only for the optical nerve the interobserver variation is significantly lower in CT compared to MRI (median MSD in CT: 0.58 mm, MRI-T1w: 1.27 mm, MRI-T2w: 1.40 mm

  1. Optimization of CT image reconstruction algorithms for the lung tissue research consortium (LTRC)

    NASA Astrophysics Data System (ADS)

    McCollough, Cynthia; Zhang, Jie; Bruesewitz, Michael; Bartholmai, Brian

    2006-03-01

    To create a repository of clinical data, CT images and tissue samples and to more clearly understand the pathogenetic features of pulmonary fibrosis and emphysema, the National Heart, Lung, and Blood Institute (NHLBI) launched a cooperative effort known as the Lung Tissue Resource Consortium (LTRC). The CT images for the LTRC effort must contain accurate CT numbers in order to characterize tissues, and must have high-spatial resolution to show fine anatomic structures. This study was performed to optimize the CT image reconstruction algorithms to achieve these criteria. Quantitative analyses of phantom and clinical images were conducted. The ACR CT accreditation phantom containing five regions of distinct CT attenuations (CT numbers of approximately -1000 HU, -80 HU, 0 HU, 130 HU and 900 HU), and a high-contrast spatial resolution test pattern, was scanned using CT systems from two manufacturers (General Electric (GE) Healthcare and Siemens Medical Solutions). Phantom images were reconstructed using all relevant reconstruction algorithms. Mean CT numbers and image noise (standard deviation) were measured and compared for the five materials. Clinical high-resolution chest CT images acquired on a GE CT system for a patient with diffuse lung disease were reconstructed using BONE and STANDARD algorithms and evaluated by a thoracic radiologist in terms of image quality and disease extent. The clinical BONE images were processed with a 3 x 3 x 3 median filter to simulate a thicker slice reconstructed in smoother algorithms, which have traditionally been proven to provide an accurate estimation of emphysema extent in the lungs. Using a threshold technique, the volume of emphysema (defined as the percentage of lung voxels having a CT number lower than -950 HU) was computed for the STANDARD, BONE, and BONE filtered. The CT numbers measured in the ACR CT Phantom images were accurate for all reconstruction kernels for both manufacturers. As expected, visual evaluation of the

  2. Precise anatomy localization in CT data by an improved probabilistic tissue type atlas

    NASA Astrophysics Data System (ADS)

    Franz, Astrid; Schadewaldt, Nicole; Schulz, Heinrich; Vik, Torbjørn; Bergtholdt, Martin; Bystrov, Daniel

    2016-03-01

    Automated interpretation of CT scans is an important, clinically relevant area as the number of such scans is increasing rapidly and the interpretation is time consuming. Anatomy localization is an important prerequisite for any such interpretation task. This can be done by image-to-atlas registration, where the atlas serves as a reference space for annotations such as organ probability maps. Tissue type based atlases allow fast and robust processing of arbitrary CT scans. Here we present two methods which significantly improve organ localization based on tissue types. A first problem is the definition of tissue types, which until now is done heuristically based on experience. We present a method to determine suitable tissue types from sample images automatically. A second problem is the restriction of the transformation space: all prior approaches use global affine maps. We present a hierarchical strategy to refine this global affine map. For each organ or region of interest a localized tissue type atlas is computed and used for a subsequent local affine registration step. A three-fold cross validation on 311 CT images with different fields-of-view demonstrates a reduction of the organ localization error by 33%.

  3. X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT.

    PubMed

    Aootaphao, Sorapong; Thongvigitmanee, Saowapak S; Rajruangrabin, Jartuwat; Thanasupsombat, Chalinee; Srivongsa, Tanapon; Thajchayapong, Pairash

    2016-01-01

    Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM) method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS) software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT) data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain.

  4. X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT

    PubMed Central

    Aootaphao, Sorapong; Thongvigitmanee, Saowapak S.; Rajruangrabin, Jartuwat; Thanasupsombat, Chalinee; Srivongsa, Tanapon; Thajchayapong, Pairash

    2016-01-01

    Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM) method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS) software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT) data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain. PMID:27022608

  5. Interaction of thyroid hormone with brown adipose tissue. Lessons learned from PET-CT.

    PubMed

    Steinhoff, Karen G; Hankir, M; Krause, K; Tönjes, A; Fenske, W K; Sabri, O; Hesse, S

    2015-01-01

    Brown adipose tissue (BAT) plays an important role in regulating core-body temperature in various species including man. [18F]FDG-PET/CT imaging first revealed the presence of metabolically active BAT depots and that decreased BAT function is associated with various metabolic conditions. Thyroid hormone (TH) in concert with sympathetic nervous system signalling (SNS) stimulates BAT thermogenesis and thyroid disorders result in dysfunctional BAT. Currently, research is focussing not only on BAT regulation but also on browning of white adipose tissue (WAT) to BAT beige adipose tissue (BeAT) in order to develop novel treatments for human obesity and related conditions. While [18F]FDG-PET/CT imaging is continuing to provide valuable insights into BAT and BeAT function in health and disease, there is a pressing need to develop alternative radiotracers that reliably track their activity in vivo. As a result it is expected that preclinical micro PET/CT investigations of BAT and BeAT will gain in prominence. The aim of this short review is to i) describe fundamentals in BAT biology, ii) highlight some of the clinical and preclinical studies performed on humans and rodents with a focus on TH, BAT and PET/CT, and iii) bridge these data with our own studies within the DFG thyroid transact priority program.

  6. Urinary Tract Infection Caused by Citrobacter koseri in a Patient With Spina Bifida, an Ileal Conduit and Renal Caluli Progressing to Peri-nephric Abscess and Empyema.

    PubMed

    Stewart, Zachary E; Shaker, Mohammed; Baxter, J David

    2017-02-01

    Urological problems are common in spina bifida and are often treated with urinary diversions. Spina bifida and ileal conduits put patients at increased risk for ascending urinary tract infections. Here we present a novel case of a Citrobacter koseri urinary tract infection complicated by a perinephric abscess with pleural extension. To our knowledge, no case of an ascending C. koseri UTI progressing to peri-nephric abscess and empyema by direct extension exists in the literature.

  7. Direct microCT imaging of non-mineralized connective tissues at high resolution.

    PubMed

    Naveh, Gili R S; Brumfeld, Vlad; Dean, Mason; Shahar, Ron; Weiner, Steve

    2014-01-01

    The 3D imaging of soft tissues in their native state is challenging, especially when high resolution is required. An X-ray-based microCT is, to date, the best choice for high resolution 3D imaging of soft tissues. However, since X-ray attenuation of soft tissues is very low, contrasting enhancement using different staining materials is needed. The staining procedure, which also usually involves tissue fixation, causes unwanted and to some extent unknown tissue alterations. Here, we demonstrate that a method that enables 3D imaging of soft tissues without fixing and staining using an X-ray-based bench-top microCT can be applied to a variety of different tissues. With the sample mounted in a custom-made loading device inside a humidity chamber, we obtained soft tissue contrast and generated 3D images of fresh, soft tissues with a resolution of 1 micron voxel size. We identified three critical conditions which make it possible to image soft tissues: humidified environment, mechanical stabilization of the sample and phase enhancement. We demonstrate the capability of the technique using different specimens: an intervertebral disc, the non-mineralized growth plate, stingray tessellated radials (calcified cartilage) and the collagenous network of the periodontal ligament. Since the scanned specimen is fresh an interesting advantage of this technique is the ability to scan a specimen under load and track the changes of the different structures. This method offers a unique opportunity for obtaining valuable insights into 3D structure-function relationships of soft tissues.

  8. Dosimetry concepts for scanner quality assurance and tissue dose assessment in micro-CT

    SciTech Connect

    Hupfer, Martin; Kolditz, Daniel; Nowak, Tristan; Eisa, Fabian; Brauweiler, Robert; Kalender, Willi A.

    2012-02-15

    Purpose: At present, no established methods exist for dosimetry in micro computed tomography (micro-CT). The purpose of this study was therefore to investigate practical concepts for both dosimetric scanner quality assurance and tissue dose assessment for micro-CT. Methods: The computed tomography dose index (CTDI) was adapted to micro-CT and measurements of the CTDI both free in air and in the center of cylindrical polymethyl methacrylate (PMMA) phantoms of 20 and 32 mm diameter were performed in a 6 month interval with a 100 mm pencil ionization chamber calibrated for low tube voltages. For tissue dose assessment, z-profile measurements using thermoluminescence dosimeters (TLDs) were performed and both profile and CTDI measurements were compared to Monte Carlo (MC) dose calculations to validate an existing MC tool for use in micro-CT. The consistency of MC calculations and TLD measurements was further investigated in two mice cadavers. Results: CTDI was found to be a reproducible quantity for constancy tests on the micro-CT system under study, showing a linear dependence on tube voltage and being by definition proportional to mAs setting and z-collimation. The CTDI measured free in air showed larger systematic deviations after the 6 month interval compared to the CTDI measured in PMMA phantoms. MC calculations were found to match CTDI measurements within 3% when using x-ray spectra measured at our micro-CT installation and better than 10% when using x-ray spectra calculated from semi-empirical models. Visual inspection revealed good agreement for all z-profiles. The consistency of MC calculations and TLD measurements in mice was found to be better than 10% with a mean deviation of 4.5%. Conclusions: Our results show the CTDI implemented for micro-CT to be a promising candidate for dosimetric quality assurance measurements as it linearly reflects changes in tube voltage, mAs setting, and collimation used during the scan, encouraging further studies on a variety of

  9. Soft Tissue Morphometry of the Malleus–Incus Complex from Micro-CT Imaging

    PubMed Central

    Sim, Jae Hoon

    2008-01-01

    The malleus–incus complex (MIC) is unique to mammalian hearing. To develop a comprehensive biomechanical MIC model for the human middle ear, measurements regarding its anatomical features are a necessity. Micro-scale X-ray computed tomography (micro-CT) imaging, which is known to be a suitable method for imaging high-density tissue such as middle-ear ossicles and surrounding bones, is used in this study to determine the three-dimensional (3-D) morphometry of the soft tissue attachments of the MIC. The MIC morphometry is based on their 3-D reconstruction from micro-CT image slices with resolutions ranging from 10 to 20 μm. The suspensory ligament and tendon attachments of the malleus and the incus as well as the incudomalleal joint (IMJ), are quantified in terms of dimensions, positions, and orientations for four human cadaver temporal bones. The malleus principal frame, the incus principal frame, and the MIC principle frame are calculated and the morphometry is reported in relation to each of these frames for the first time. The resulting values show significant variation across ear samples, suggesting that models of the MIC should be based on individual anatomy. The IMJ morphometry dimensions appear to be proportional to the ossicular mass. The micro-CT imaging modality is a nondestructive and relatively fast method for obtaining soft tissue morphometry and provides accurate anatomical features in relation to the principal axes of bones. PMID:18311579

  10. Automated characterization of normal and pathologic lung tissue by topological texture analysis of multidetector CT

    NASA Astrophysics Data System (ADS)

    Boehm, H. F.; Fink, C.; Becker, C.; Reiser, M.

    2007-03-01

    Reliable and accurate methods for objective quantitative assessment of parenchymal alterations in the lung are necessary for diagnosis, treatment and follow-up of pulmonary diseases. Two major types of alterations are pulmonary emphysema and fibrosis, emphysema being characterized by abnormal enlargement of the air spaces distal to the terminal, nonrespiratory bronchiole, accompanied by destructive changes of the alveolar walls. The main characteristic of fibrosis is coursening of the interstitial fibers and compaction of the pulmonary tissue. With the ability to display anatomy free from superimposing structures and greater visual clarity, Multi-Detector-CT has shown to be more sensitive than the chest radiograph in identifying alterations of lung parenchyma. In automated evaluation of pulmonary CT-scans, quantitative image processing techniques are applied for objective evaluation of the data. A number of methods have been proposed in the past, most of which utilize simple densitometric tissue features based on the mean X-ray attenuation coefficients expressed in terms of Hounsfield Units [HU]. Due to partial volume effects, most of the density-based methodologies tend to fail, namely in cases, where emphysema and fibrosis occur within narrow spatial limits. In this study, we propose a methodology based upon the topological assessment of graylevel distribution in the 3D image data of lung tissue which provides a way of improving quantitative CT evaluation. Results are compared to the more established density-based methods.

  11. Analysis of CT Numbers and Relative Proton Stopping Powers for Real Tissue Samples

    SciTech Connect

    Ryazantsev, Oleg; Karpunin, Vladimir; Haibullin, Vadim; Matusova, Tatiana

    2010-01-05

    The accuracy of computer planning of clinical proton dose distribution is partly determined by the precision of the conversion of CT Hounsfield Units to relative proton stopping powers. The calibration curves from three different sources were compared. We have found about 5% differences between proton stopping power values in the range from -700 HU to 0 HU. Calibration data for several soft tissues and phantom materials were also experimentally measured. The data for the tissues are in a good agreement with the calibration curves however data for phantom materials have significant deviations.

  12. Value and limits of μ-CT for nondemineralized bone tissue processing.

    PubMed

    Draenert, Miriam Esther; Draenert, Alice Irène; Forriol, Francisco; Cerler, Michael; Kunzelmann, Karl-Heinz; Hickel, Reinhard; Draenert, Klaus

    2012-04-01

    An experimental approach was performed on 20 giant rabbits to establish the possibilities and limitations of μ-CT for routine processing of nondemineralized bone tissue. Hydroxyapatite (HA) or β-tricalciumphosphate (β-TCP) bead implants or a melange of both, microchambered and solid, were implanted into a standardized and precise defect in the patellar groove. The bone-healing phase was chosen for the histology considering 1 or 2 days, and 2, 3, and 6 weeks. Normal X-ray and μ-CT were applied on all specimens; five specimens in the 6-week stage were additionally processed according to the full range of conventional nondemineralized bone processing methods. μ-CT increased the possibilities of nondemineralized histology with respect to bone morphometry and a complete sequence of sections, thus providing a complete analysis of the bone response. μ-CT was limited in differentiating bone quality, cell analyses, and mineralization stages. The investigation based on normal X-rays is limited to defining integration and excluding the fibrous and bony encapsulation of loose implants. μ-CT allows a 3D evaluation of newly formed bone which is clearly marked against the ceramic implant. It does not allow, however, for the differentiation between woven and lamellar bone, the presentation of the canalicular lacunar system, or on the cell level, revealing canaliculi or details of the mineralization process which can be documented by high-resolution microradiography. Titer dynamics of bone formation remains the domain of polychromatic sequential labeling. The complete sequence of μ-CT slices enhances the possibilities for routine histology, tremendously allowing to the focus on detail histology to topographically well-defined cuts, thus providing more precise conclusions which take into consideration the whole implant.

  13. Processing of CT images for analysis of diffuse lung disease in the lung tissue research consortium

    NASA Astrophysics Data System (ADS)

    Karwoski, Ronald A.; Bartholmai, Brian; Zavaletta, Vanessa A.; Holmes, David; Robb, Richard A.

    2008-03-01

    The goal of Lung Tissue Resource Consortium (LTRC) is to improve the management of diffuse lung diseases through a better understanding of the biology of Chronic Obstructive Pulmonary Disease (COPD) and fibrotic interstitial lung disease (ILD) including Idiopathic Pulmonary Fibrosis (IPF). Participants are subjected to a battery of tests including tissue biopsies, physiologic testing, clinical history reporting, and CT scanning of the chest. The LTRC is a repository from which investigators can request tissue specimens and test results as well as semi-quantitative radiology reports, pathology reports, and automated quantitative image analysis results from the CT scan data performed by the LTRC core laboratories. The LTRC Radiology Core Laboratory (RCL), in conjunction with the Biomedical Imaging Resource (BIR), has developed novel processing methods for comprehensive characterization of pulmonary processes on volumetric high-resolution CT scans to quantify how these diseases manifest in radiographic images. Specifically, the RCL has implemented a semi-automated method for segmenting the anatomical regions of the lungs and airways. In these anatomic regions, automated quantification of pathologic features of disease including emphysema volumes and tissue classification are performed using both threshold techniques and advanced texture measures to determine the extent and location of emphysema, ground glass opacities, "honeycombing" (HC) and "irregular linear" or "reticular" pulmonary infiltrates and normal lung. Wall thickness measurements of the trachea, and its branches to the 3 rd and limited 4 th order are also computed. The methods for processing, segmentation and quantification are described. The results are reviewed and verified by an expert radiologist following processing and stored in the public LTRC database for use by pulmonary researchers. To date, over 1200 CT scans have been processed by the RCL and the LTRC project is on target for recruitment of the

  14. A general method to derive tissue parameters for Monte Carlo dose calculation with multi-energy CT.

    PubMed

    Lalonde, Arthur; Bouchard, Hugo

    2016-11-21

    To develop a general method for human tissue characterization with dual- and multi-energy CT and evaluate its performance in determining elemental compositions and quantities relevant to radiotherapy Monte Carlo dose calculation. Ideal materials to describe human tissue are obtained applying principal component analysis on elemental weight and density data available in literature. The theory is adapted to elemental composition for solving tissue information from CT data. A novel stoichiometric calibration method is integrated to the technique to make it suitable for a clinical environment. The performance of the method is compared with two techniques known in literature using theoretical CT data. In determining elemental weights with dual-energy CT, the method is shown to be systematically superior to the water-lipid-protein material decomposition and comparable to the parameterization technique. In determining proton stopping powers and energy absorption coefficients with dual-energy CT, the method generally shows better accuracy and unbiased results. The generality of the method is demonstrated simulating multi-energy CT data to show the potential to extract more information with multiple energies. The method proposed in this paper shows good performance to determine elemental compositions from dual-energy CT data and physical quantities relevant to radiotherapy dose calculation. The method is particularly suitable for Monte Carlo calculations and shows promise in using more than two energies to characterize human tissue with CT.

  15. Breast Tissue Characterization with Photon-counting Spectral CT Imaging: A Postmortem Breast Study

    PubMed Central

    Ding, Huanjun; Klopfer, Michael J.; Ducote, Justin L.; Masaki, Fumitaro

    2014-01-01

    Purpose To investigate the feasibility of breast tissue characterization in terms of water, lipid, and protein contents with a spectral computed tomographic (CT) system based on a cadmium zinc telluride (CZT) photon-counting detector by using postmortem breasts. Materials and Methods Nineteen pairs of postmortem breasts were imaged with a CZT-based photon-counting spectral CT system with beam energy of 100 kVp. The mean glandular dose was estimated to be in the range of 1.8–2.2 mGy. The images were corrected for pulse pile-up and other artifacts by using spectral distortion corrections. Dual-energy decomposition was then applied to characterize each breast into water, lipid, and protein contents. The precision of the three-compartment characterization was evaluated by comparing the composition of right and left breasts, where the standard error of the estimations was determined. The results of dual-energy decomposition were compared by using averaged root mean square to chemical analysis, which was used as the reference standard. Results The standard errors of the estimations of the right-left correlations obtained from spectral CT were 7.4%, 6.7%, and 3.2% for water, lipid, and protein contents, respectively. Compared with the reference standard, the average root mean square error in breast tissue composition was 2.8%. Conclusion Spectral CT can be used to accurately quantify the water, lipid, and protein contents in breast tissue in a laboratory study by using postmortem specimens. © RSNA, 2014 PMID:24814180

  16. Validation of finite element models of liver tissue using micro-CT.

    PubMed

    Shi, Hongjian; Farag, Aly A; Fahmi, Rachid; Chen, Dongqing

    2008-03-01

    In this work, we aim at validating some soft tissue deformation models using high-resolution micro-computed tomography (Micro-CT) images. The imaging technique plays a key role in detecting the tissue deformation details in the contact region between the tissue and the surgical tool (probe) for small force loads and provides good capabilities of creating accurate 3-D models of soft tissues. Surgical simulations rely on accurate representation of the mechanical response of soft tissues subjected to surgical manipulations. Several finite-element models have been suggested to characterize soft tissues. However, validating these models for specific tissues still remain a challenge. In this study, ex vivo lamb liver tissue is chosen to validate the linear elastic model (LEM), the linear viscoelastic model (LVEM), and the neo-Hooke hyperelastic model (NHM). We find that the LEM is more applicable to lamb liver than the LVEM for smaller force loads (< 20 g) and that the NHM is closer to reality than the LVEM for the range of force loads from 5 to 40 g.

  17. Therapeutic impact of CT-guided percutaneous catheter drainage in treatment of deep tissue abscesses.

    PubMed

    Asai, Nobuhiro; Ohkuni, Yoshihiro; Yamazaki, Ikuo; Kaneko, Norihiro; Aoshima, Masahiro; Kawamura, Yasutaka

    2013-01-01

    Combination therapy of CT-guided percutaneous drainage and antibiotics is the first-line treatment for abscesses. Its effectiveness has been demonstrated. However, the therapeutic impact of this procedure for infection treatment has never been reported. We retrospectively analyzed all 47 patients who received CT-guided percutaneous drainage for infection treatment. Patients' characteristics, pathogens isolated, antibiotics administered, technical and clinical outcomes, complications related to this procedure and therapeutic impacts were investigated. Patients were 26 males and 21 females. The mean age was 63.5 years (±18.7). The diseases targeted were 19 retroperitoneal abscesses, 18 intra-abdominal abscesses, three pelvic abscesses, and seven others. As for technical outcomes, all of the 54 procedures (100%) were successful. As for clinical outcomes, 44 (93.6%) were cured and three patients (6.4%) died. No complications related to this procedure were found in this study. A total of 42 patients (88%) had a change in the management of their infection as a result of CT-guided percutaneous drainage, such as selection and discontinuation of antibiotics. In conclusion, CT-guided percutaneous drainage is a safe and favorable procedure in the treatment of deep tissue abscesses. Therapeutic impact of these procedures helped physicians make a rational decision for antibiotics selection.

  18. Quantification of Regional Interstitial Lung Disease from CT-derived Fractional Tissue Volume: A Lung Tissue Research Consortium Study

    PubMed Central

    Yilmaz, Cuneyt; Watharkar, Snehal S.; de Leon, Alberto Diaz; Garcia, Christine K.; Patel, Nova C.; Jordan, Kirk G.; Hsia, Connie C.W.

    2011-01-01

    Rationale and Objectives Evaluation of chest CT is usually qualitative or semi-quantitative, resulting in subjective descriptions often by different observers over time and imprecise determinations of disease severity within distorted lobes. There is a need for standardized imaging biomarkers to quantify regional disease, maximize diagnostic yield, and facilitate multi-center comparisons. We applied lobe-based voxelwise image analysis to derive regional air (Vair) and tissue (Vtissue) volumes and fractional tissue volume (FTV=tissue/[tissue+air] volume) as internally standardized parameter for assessing interstitial lung disease (ILD). Materials and Methods High-resolution CT was obtained at supine and prone end-inspiration and supine end-expiration in 29 patients with ILD and 20 normal subjects. Lobar Vair, Vtissue, and FTV were expressed along standard coordinate axes. Results In normal subjects from end-inspiration to end-expiration, total Vair declined 43%, FTV increased ~80% while Vtissue remained unchanged. With increasing ILD, Vair declined and Vtissue rose in all lobes; FTV increased with a peripheral-to-central progression inversely correlated to spirometry and lung diffusing capacity (R2=0.57–0.75, prone end-inspiration). Inter- and intra-lobar coefficients of variation (CVs) of FTV increased 84–148% in mild-to-moderate ILD, indicating greater spatial heterogeneity, then normalized in severe ILD. Analysis of discontinuous images incurs <3% error compared to consecutive images. Conclusions These regional attenuation-based biomarkers could quantify heterogeneous parenchymal disease in distorted lobes, detect mild ILD involvement in all lobes and describe the pattern of disease progression. The next step would be to study a larger series, examine reproducibility and follow longitudinal changes in correlation with clinical and functional indices. PMID:21596593

  19. CT imaging during microwave ablation: Analysis of spatial and temporal tissue contraction

    SciTech Connect

    Liu, Dong; Brace, Christopher L.

    2014-11-01

    Purpose: To analyze the spatial distribution and temporal development of liver tissue contraction during high-temperature ablation by using intraprocedural computed tomography (CT) imaging. Methods: A total of 46 aluminum fiducial markers were positioned in a 60 × 45 mm grid, in a single plane, around a microwave ablation antenna in each of six ex vivo bovine liver samples. Ablations were performed for 10 min at 100 W. CT data of the liver sample were acquired every 30 s during ablation. Fiducial motion between acquisitions was tracked in postprocessing and used to calculate measures of tissue contraction and contraction rates. The spatial distribution and temporal evolution of contraction were analyzed. Results: Fiducial displacement indicated that the zone measured postablation was 8.2 ± 1.8 mm (∼20%) smaller in the radial direction and 7.1 ± 1.0 mm (∼10%) shorter in the longitudinal direction than the preablation tissue dimension. Therefore, the total ablation volume was reduced from its preablation value by approximately 45%. Very little longitudinal contraction was noted in the distal portion of the ablation zone. Central tissues contracted more than 60%, which was near an estimated limit of ∼70% based on initial water content. More peripheral tissues contracted only 15% in any direction. Contraction rates peaked during the first 60 s of heating with a roughly exponential decay over time. Conclusions: Ablation zones measured posttreatment are significantly smaller than the pretreatment tissue dimensions. Tissue contraction is spatially dependent, with the greatest effect occurring in the central ablation zone. Contraction rate peaks early and decays over time.

  20. Range prediction for tissue mixtures based on dual-energy CT

    NASA Astrophysics Data System (ADS)

    Möhler, Christian; Wohlfahrt, Patrick; Richter, Christian; Greilich, Steffen

    2016-06-01

    The use of dual-energy CT (DECT) potentially decreases range uncertainties in proton and ion therapy treatment planning via determination of the involved physical target quantities. For eventual clinical application, the correct treatment of tissue mixtures and heterogeneities is an essential feature, as they naturally occur within a patient’s CT. Here, we present how existing methods for DECT-based ion-range prediction can be modified in order to incorporate proper mixing behavior on several structural levels. Our approach is based on the factorization of the stopping-power ratio into the relative electron density and the relative stopping number. The latter is confined for tissue between about 0.95 and 1.02 at a therapeutic beam energy of 200 MeV u-1 and depends on the I-value. We show that convenient mixing and averaging properties arise by relating the relative stopping number to the relative cross section obtained by DECT. From this, a maximum uncertainty of the stopping-power ratio prediction below 1% is suggested for arbitrary mixtures of human body tissues.

  1. PET/CT for Radiotherapy Treatment Planning in Patients With Soft Tissue Sarcomas

    SciTech Connect

    Karam, Irene; Devic, Slobodan; Hickeson, Marc; Roberge, David; Turcotte, Robert E.; Freeman, Carolyn R.

    2009-11-01

    Purpose: To study the possibility of incorporating positron emission tomography/computed tomography (PET/CT) information into radiotherapy treatment planning in patients with high-grade soft tissue sarcomas (STS). Methods and Materials: We studied 17 patients treated with preoperative radiotherapy at our institution from 2005 to 2007. All patients had a high-grade STS and had had a staging PET/CT scan. For each patient, an MRI-based gross tumor volume (GTV), considered to be the contemporary standard for radiotherapy treatment planning, was outlined on a T1-gadolinium enhanced axial MRI (GTV{sub MRI}), and a second set of GTVs were outlined using different threshold values on PET images (GTV{sub PET}). PET-based target volumes were compared with the MRI-based GTV. Threshold values for target contouring were determined as a multiple (from 2 to 10 times) of the background soft tissue uptake values (B) sampled over healthy tissue. Results: PET-based GTVs contoured using a threshold value of 2 or 2.5 most closely resembled the GTV{sub MRI} volumes. Higher threshold values lead to PET volumes much smaller than the GTV{sub MRI}. The standard deviations between the average volumes of GTV{sub PET} and GTV{sub MRI} ratios for all thresholds were large, ranging from 36% for 2 xB up to 93% for 10 xB. Maximum uptake-to-background ratio correlated poorly with the maximum standardized uptake values. Conclusions: It is unlikely that PET/CT will make a significant contribution in GTV definition for radiotherapy treatment planning in patients with STS using threshold methods on PET images. Future studies will focus on molecular imaging and tumor physiology.

  2. Soft-tissue imaging with C-arm cone-beam CT using statistical reconstruction

    NASA Astrophysics Data System (ADS)

    Wang, Adam S.; Webster Stayman, J.; Otake, Yoshito; Kleinszig, Gerhard; Vogt, Sebastian; Gallia, Gary L.; Khanna, A. Jay; Siewerdsen, Jeffrey H.

    2014-02-01

    The potential for statistical image reconstruction methods such as penalized-likelihood (PL) to improve C-arm cone-beam CT (CBCT) soft-tissue visualization for intraoperative imaging over conventional filtered backprojection (FBP) is assessed in this work by making a fair comparison in relation to soft-tissue performance. A prototype mobile C-arm was used to scan anthropomorphic head and abdomen phantoms as well as a cadaveric torso at doses substantially lower than typical values in diagnostic CT, and the effects of dose reduction via tube current reduction and sparse sampling were also compared. Matched spatial resolution between PL and FBP was determined by the edge spread function of low-contrast (˜40-80 HU) spheres in the phantoms, which were representative of soft-tissue imaging tasks. PL using the non-quadratic Huber penalty was found to substantially reduce noise relative to FBP, especially at lower spatial resolution where PL provides a contrast-to-noise ratio increase up to 1.4-2.2× over FBP at 50% dose reduction across all objects. Comparison of sampling strategies indicates that soft-tissue imaging benefits from fully sampled acquisitions at dose above ˜1.7 mGy and benefits from 50% sparsity at dose below ˜1.0 mGy. Therefore, an appropriate sampling strategy along with the improved low-contrast visualization offered by statistical reconstruction demonstrates the potential for extending intraoperative C-arm CBCT to applications in soft-tissue interventions in neurosurgery as well as thoracic and abdominal surgeries by overcoming conventional tradeoffs in noise, spatial resolution, and dose.

  3. Micro-CT-based screening of biomechanical and structural properties of bone tissue engineering scaffolds.

    PubMed

    Van Cleynenbreugel, Tim; Schrooten, Jan; Van Oosterwyck, Hans; Vander Sloten, Jos

    2006-07-01

    The development of successful scaffolds for bone tissue engineering requires a concurrent engineering approach that combines different research fields. In order to limit in vivo experiments and reduce trial and error research, a scaffold screening technique has been developed. In this protocol seven structural and three biomechanical properties of potential scaffold materials are quantified and compared to the desired values. The property assessment is done on computer models of the scaffolds, and these models are based on micro-CT images. As a proof of principle, three porous scaffolds were evaluated with this protocol: stainless steel, hydroxyapatite, and titanium. These examples demonstrate that the modelling technique is able to quantify important scaffold properties. Thus, a powerful technique for automated screening of bone tissue engineering scaffolds has been developed that in a later stage may be used to tailor the scaffold properties to specific requirements.

  4. Automatic segmentation of human facial tissue by MRI-CT fusion: a feasibility study.

    PubMed

    Kale, Emre H; Mumcuoglu, Erkan U; Hamcan, Salih

    2012-12-01

    The aim of this study was to develop automatic image segmentation methods to segment human facial tissue which contains very thin anatomic structures. The segmentation output can be used to construct a more realistic human face model for a variety of purposes like surgery planning, patient specific prosthesis design and facial expression simulation. Segmentation methods developed were based on Bayesian and Level Set frameworks, which were applied on three image types: magnetic resonance imaging (MRI), computerized tomography (CT) and fusion, in which case information from both modalities were utilized maximally for every tissue type. The results on human data indicated that fusion, thickness adaptive and postprocessing options provided the best muscle/fat segmentation scores in both Level Set and Bayesian methods. When the best Level Set and Bayesian methods were compared, scores of the latter were better. Number of algorithm parameters (to be trained) and computer run time measured were also in favour of the Bayesian method.

  5. Soft-tissue changes after head and neck radiation: CT findings.

    PubMed

    Bronstein, A D; Nyberg, D A; Schwartz, A N; Shuman, W P; Griffin, B R

    1989-01-01

    To identify possible soft-tissue changes of the head and neck after radiation therapy, 102 CT scans from 78 patients with head and neck tumors were reviewed to assess (1) skin thickening, (2) epiglottic thickening, (3) stranding of subcutaneous fat, and (4) stranding of deep cervical fat. Scans were obtained after radiation therapy alone (10 cases), after radiation and surgery (27 cases), after surgery alone (24 cases), or before either surgery or radiation (41 cases). Skin thickening, epiglottic thickening, and stranding of subcutaneous fat were seen more frequently after radiation therapy than before such treatment. However, skin thickening and stranding of subcutaneous fat were sometimes also associated with tumor involvement and/or previous surgery, while epiglottic thickening was only occasionally associated with tumor involvement. Stranding of deep cervical fat was noted with increased frequency after radiation or surgery, but postradiation effects could not be reliably distinguished from postsurgical or tumor effects. We conclude that soft-tissue changes of the head and neck on CT may commonly be associated with previous radiation therapy, but these postradiation effects are not always distinguishable from postsurgical effects or tumor.

  6. Improved correction for the tissue fraction effect in lung PET/CT imaging

    NASA Astrophysics Data System (ADS)

    Holman, Beverley F.; Cuplov, Vesna; Millner, Lynn; Hutton, Brian F.; Maher, Toby M.; Groves, Ashley M.; Thielemans, Kris

    2015-09-01

    Recently, there has been an increased interest in imaging different pulmonary disorders using PET techniques. Previous work has shown, for static PET/CT, that air content in the lung influences reconstructed image values and that it is vital to correct for this ‘tissue fraction effect’ (TFE). In this paper, we extend this work to include the blood component and also investigate the TFE in dynamic imaging. CT imaging and PET kinetic modelling are used to determine fractional air and blood voxel volumes in six patients with idiopathic pulmonary fibrosis. These values are used to illustrate best and worst case scenarios when interpreting images without correcting for the TFE. In addition, the fractional volumes were used to determine correction factors for the SUV and the kinetic parameters. These were then applied to the patient images. The kinetic parameters K1 and Ki along with the static parameter SUV were all found to be affected by the TFE with both air and blood providing a significant contribution to the errors. Without corrections, errors range from 34-80% in the best case and 29-96% in the worst case. In the patient data, without correcting for the TFE, regions of high density (fibrosis) appeared to have a higher uptake than lower density (normal appearing tissue), however this was reversed after air and blood correction. The proposed correction methods are vital for quantitative and relative accuracy. Without these corrections, images may be misinterpreted.

  7. Experimental verification of ion stopping power prediction from dual energy CT data in tissue surrogates.

    PubMed

    Hünemohr, Nora; Krauss, Bernhard; Tremmel, Christoph; Ackermann, Benjamin; Jäkel, Oliver; Greilich, Steffen

    2014-01-06

    We present an experimental verification of stopping-power-ratio (SPR) prediction from dual energy CT (DECT) with potential use for dose planning in proton and ion therapy. The approach is based on DECT images converted to electron density relative to water ϱe/ϱe, w and effective atomic number Zeff. To establish a parameterization of the I-value by Zeff, 71 tabulated tissue compositions were used. For the experimental assessment of the method we scanned 20 materials (tissue surrogates, polymers, aluminum, titanium) at 80/140Sn kVp and 100/140Sn kVp (Sn: additional tin filtration) and computed the ϱe/ϱe, w and Zeff with a purely image based algorithm. Thereby, we found that ϱe/ϱe, w (Zeff) could be determined with an accuracy of 0.4% (1.7%) for the tissue surrogates with known elemental compositions. SPRs were predicted from DECT images for all 20 materials using the presented approach and were compared to measured water-equivalent path lengths (closely related to SPR). For the tissue surrogates the presented DECT approach was found to predict the experimental values within 0.6%, for aluminum and titanium within an accuracy of 1.7% and 9.4% (from 16-bit reconstructed DECT images).

  8. Modeling of body tissues for Monte Carlo simulation of radiotherapy treatments planned with conventional x-ray CT systems

    NASA Astrophysics Data System (ADS)

    Kanematsu, Nobuyuki; Inaniwa, Taku; Nakao, Minoru

    2016-07-01

    In the conventional procedure for accurate Monte Carlo simulation of radiotherapy, a CT number given to each pixel of a patient image is directly converted to mass density and elemental composition using their respective functions that have been calibrated specifically for the relevant x-ray CT system. We propose an alternative approach that is a conversion in two steps: the first from CT number to density and the second from density to composition. Based on the latest compilation of standard tissues for reference adult male and female phantoms, we sorted the standard tissues into groups by mass density and defined the representative tissues by averaging the material properties per group. With these representative tissues, we formulated polyline relations between mass density and each of the following; electron density, stopping-power ratio and elemental densities. We also revised a procedure of stoichiometric calibration for CT-number conversion and demonstrated the two-step conversion method for a theoretically emulated CT system with hypothetical 80 keV photons. For the standard tissues, high correlation was generally observed between mass density and the other densities excluding those of C and O for the light spongiosa tissues between 1.0 g cm-3 and 1.1 g cm-3 occupying 1% of the human body mass. The polylines fitted to the dominant tissues were generally consistent with similar formulations in the literature. The two-step conversion procedure was demonstrated to be practical and will potentially facilitate Monte Carlo simulation for treatment planning and for retrospective analysis of treatment plans with little impact on the management of planning CT systems.

  9. High-resolution CT analysis of facial struts in trauma: 2. Osseous and soft-tissue complications.

    PubMed

    Gentry, L R; Manor, W F; Turski, P A; Strother, C M

    1983-03-01

    In six cadavers, high-resolution thin-section computed tomography (CT) was used to evaluate the sequelae of experimentally produced facial trauma. As confirmed by pluridirectional tomography, CT was an effective imaging method for the detection and classification of facial fractures. The ability of CT to simultaneously depict both osseous and soft-tissue structures expands the role that diagnostic radiology can play in the evaluation of the traumatized face. A method of evaluation is presented in which the face is geometrically conceptualized as a series of triplanar (horizontal, sagittal, and coronal) osseous struts. Sequential, systematic assessment of each strut for fracture and its adjacent soft tissue for injury can facilitate evaluation of the traumatized face. Using this approach the osseous and soft-tissue complications arising from experimentally produced trauma are reviewed and illustrated with CT. Examples of potential soft-tissue complications that may occur with fractures of the horizontal group of struts include disruption of the dura matter at the cribiform plate, involvement of the structures of the anterior cranial fossa, injury to the optic nerve, and involvement of the superior and inferior groups of extraocular muscles. Injury to the nasolacrimal duct, maxillary sinus ostium, medial and lateral rectus muscles, or the soft-tissue structures in the superior and inferior orbital fissures may arise from disruption of the sagittal struts. Fractures of the coronal struts may involve the frontal sinus, anterior cranial fossa, lacrimal gland, nasofrontal duct, lacrimal sac, or the soft tissues of the pterygopalatine fossa.

  10. Ectopic Thyroid Tissue in the Mediastinum Characterized by Histology and Functional Imaging with I-123 SPECT/CT.

    PubMed

    Hummel, Jed; Wachsmann, Jason; Carrick, Kelley; Oz, Orhan K; Mathews, Dana; Peng, Fangyu

    2017-01-01

    Ectopic thyroid tissue is a rare entity and when discovered it is typically along the pathway of embryologic migration of the thyroid. We present a case of incidental finding of ectopic thyroid tissue within mediastinum in a 61-year-old female patient with a history of total thyroidectomy for thyroiditis and nodules. The patient presented to emergency room with cough and right chest pain and underwent a chest computed tomographic angiogram (CTA) to exclude pulmonary embolism as part of chest pain workup. One right paratracheal mediastinal soft tissue nodule was visualized on the images of CTA. This right paratracheal soft tissue mass was found to be ectopic benign thyroid tissue by histological analysis of the biopsied tissue samples. The function of this ectopic thyroid tissue was characterized by I-123 radioiodine uptake and single photon emission computed tomography/computed tomography (SPECT/CT) imaging. This case illustrates that ectopic thyroid tissue should be included for differential diagnosis of a hyperdense soft tissue mass located within mediastinum. I-123 SPECT/CT is useful for guiding tissue biopsy of ectopic thyroid tissue distant from orthotopic thyroid gland and functional and anatomic characterization of mediastinal ectopic thyroid tissue for surgical resection when it is medically necessary.

  11. Ectopic Thyroid Tissue in the Mediastinum Characterized by Histology and Functional Imaging with I-123 SPECT/CT

    PubMed Central

    Hummel, Jed; Wachsmann, Jason; Carrick, Kelley; Oz, Orhan K.; Mathews, Dana

    2017-01-01

    Ectopic thyroid tissue is a rare entity and when discovered it is typically along the pathway of embryologic migration of the thyroid. We present a case of incidental finding of ectopic thyroid tissue within mediastinum in a 61-year-old female patient with a history of total thyroidectomy for thyroiditis and nodules. The patient presented to emergency room with cough and right chest pain and underwent a chest computed tomographic angiogram (CTA) to exclude pulmonary embolism as part of chest pain workup. One right paratracheal mediastinal soft tissue nodule was visualized on the images of CTA. This right paratracheal soft tissue mass was found to be ectopic benign thyroid tissue by histological analysis of the biopsied tissue samples. The function of this ectopic thyroid tissue was characterized by I-123 radioiodine uptake and single photon emission computed tomography/computed tomography (SPECT/CT) imaging. This case illustrates that ectopic thyroid tissue should be included for differential diagnosis of a hyperdense soft tissue mass located within mediastinum. I-123 SPECT/CT is useful for guiding tissue biopsy of ectopic thyroid tissue distant from orthotopic thyroid gland and functional and anatomic characterization of mediastinal ectopic thyroid tissue for surgical resection when it is medically necessary. PMID:28251012

  12. Image-guided tissue engineering of anatomically shaped implants via MRI and micro-CT using injection molding.

    PubMed

    Ballyns, Jeffery J; Gleghorn, Jason P; Niebrzydowski, Vicki; Rawlinson, Jeremy J; Potter, Hollis G; Maher, Suzanne A; Wright, Timothy M; Bonassar, Lawrence J

    2008-07-01

    This study demonstrates for the first time the development of engineered tissues based on anatomic geometries derived from widely used medical imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Computer-aided design and tissue injection molding techniques have demonstrated the ability to generate living implants of complex geometry. Due to its complex geometry, the meniscus of the knee was used as an example of this technique's capabilities. MRI and microcomputed tomography (microCT) were used to design custom-printed molds that enabled the generation of anatomically shaped constructs that retained shape throughout 8 weeks of culture. Engineered constructs showed progressive tissue formation indicated by increases in extracellular matrix content and mechanical properties. The paradigm of interfacing tissue injection molding technology can be applied to other medical imaging techniques that render 3D models of anatomy, demonstrating the potential to apply the current technique to engineering of many tissues and organs.

  13. A CT-scan database for the facial soft tissue thickness of Taiwan adults.

    PubMed

    Chung, Ju-Hui; Chen, Hsiao-Ting; Hsu, Wan-Yi; Huang, Guo-Shu; Shaw, Kai-Ping

    2015-08-01

    Facial reconstruction is a branch of forensic anthropology used to assist in the identification of skeletal remains. The majority of facial reconstruction techniques use facial soft tissue depth chart data to recreate facial tissue on a skull or a model of a skull through the use of modeling clay. This study relied on 193 subjects selected from the Taiwanese population on the basis of age and gender to determine the average values of 32 landmarks, include midline and bilateral measures, by means of CT scans. The mean age of the subjects was 46.9±16.4 years, with a mean age of 43.8±16.6 for males and 49.9±15.8 for females respectively. There were 16 landmarks with statistically significant differences between male and female subjects, namely S, G, N, Na, Ph, Sd and Id in the midline portion, FE, LO, ZA and Sub M2 in the bilateral-right and left portion, and IM point in the bilateral-left portion (abbreviations adapted from Karen T. Taylor's work). The mean soft tissue depth was greater in males than in females, and there was significant difference between the right and left sides of the face in Za point. This study's findings were compared with those of Bulut et al.

  14. Highly sensitive detection of the soft tissues based on refraction contrast by in-plane diffraction-enhanced imaging CT

    NASA Astrophysics Data System (ADS)

    Yuasa, Tetsuya; Hashimoto, Eiko; Maksimenko, Anton; Sugiyama, Hiroshi; Arai, Yoshinori; Shimao, Daisuke; Ichihara, Shu; Ando, Masami

    2008-07-01

    We discuss the recently proposed computed tomography (CT) technique based on refractive effects for biomedical use, which reconstructs the in-plane refractive-index gradient vector field in a cross-sectional plane of interest by detecting the angular deviation of the beam, refracted by a sample, from the incident beam, using the diffraction-enhanced imaging (DEI) method. The CT has advantages for delineating biological weakly absorbing soft tissues over the conventional absorption-contrast CT because of the use of phase sensitive detection. The paper aims to define the imaging scheme rigidly and to demonstrate its efficacy for non-destructive measurement of biomedical soft-tissue samples without imaging agent. We first describe the imaging principle of in-plane DEI-CT from the physico-mathematical viewpoints in detail, and investigate what physical quantities are extracted from the reconstructed images. Then, we introduce the imaging system using the synchrotron radiation as a light source, constructed at beamline BL-14B in KEK, Japan. Finally, we demonstrate the advantage of the refraction-based image for non-destructive analysis of biological sample by investigating the image of human breast cancer tumors obtained using the imaging system. Here, the refraction- and the apparent absorption-based images obtained simultaneously by the in-plane DEI-CT are compared. Also, the conventional absorption-based image obtained using micro-computed tomography (μCT) imaging system is compared with them. Thereby, it is shown that the refraction contrast much more sensitively delineates the soft tissues than the absorption contrast. In addition, the radiologic-histologic correlation study not only validates the efficacy for imaging soft tissues, but also produces the potential that the pathological inspection for the breast cancer tumors may be feasible non-destructively.

  15. Extracting tissue and cell outlines of Arabidopsis seeds using refraction contrast X-ray CT at the SPring-8 facility

    NASA Astrophysics Data System (ADS)

    Yamauchi, Daisuke; Tamaoki, Daisuke; Hayami, Masato; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Karahara, Ichirou; Mineyuki, Yoshinobu

    2012-07-01

    How biological form is determined is one of the important questions in developmental biology. Physical forces are thought to be the primary determinants of the biological forms, and several theories for this were proposed nearly a century ago. To evaluate how physical forces can influence biological forms, precise determination of cell and tissue shapes and their geometries is necessary. Computed tomography (CT) is useful for visualizing three-dimensional structures without destroying a sample. Because recent progress in micro-CT has enabled visualizing cells and tissues at the sub-micron level, we investigated if we could extract cell and tissue outlines of seeds using refraction contrast X-ray CT available at the SPring-8 synchrotron radiation facility. We used Arabidopsis seeds because Arabidopsis is a well-known model plant and its seed size is small enough to obtain whole images using the X-ray CT experimental system. We could trace the outlines of tissues in dry seeds using beamline BL20B2 (10 keV, 2.4µm.pixel-1). Although we could also detect the outlines of some cell types, the image resolution was not adequate to extract whole cell edges. To detect the edges of cells in the epidermis and cortex, we obtained CT images using beamline BL20XU (8 keV, 0.5 µm.pixel-1). With these CT images, we could extract the facets and edges of each cell and determine cell vertices. This method enabled us to compare the numbers of cell facets among various cell types. We could also describe cell geometry as a set of points that showed these cell vertices.

  16. Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

    NASA Astrophysics Data System (ADS)

    Dou, Hsiang-Tai

    The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan

  17. Specimen size and porosity can introduce error into microCT-based tissue mineral density measurements.

    PubMed

    Fajardo, Roberto J; Cory, Esther; Patel, Nipun D; Nazarian, Ara; Laib, Andres; Manoharan, Rajaram K; Schmitz, James E; DeSilva, Jeremy M; MacLatchy, Laura M; Snyder, Brian D; Bouxsein, Mary L

    2009-01-01

    The accurate measurement of tissue mineral density, rho(m), in specimens of unequal size or quantities of bone mineral using polychromatic microCT systems is important, since studies often compare samples with a range of sizes and bone densities. We assessed the influence of object size on microCT measurements of rho(m) using (1) hydroxyapatite rods (HA), (2) precision-manufactured aluminum foams (AL) simulating trabecular bone structure, and (3) bovine cortical bone cubes (BCt). Two beam-hardening correction (BHC) algorithms, determined using a 200 and 1200 mg/cm(3) HA wedge phantom, were used to calculate rho(m) of the HA and BCt. The 200 mg/cm(3) and an aluminum BHC algorithm were used to calculate the linear attenuation coefficients of the AL foams. Equivalent rho(m) measurements of 500, 1000, and 1500 mg HA/cm(3) rods decreased (r(2)>0.96, p<0.05 for all) as HA rod diameter increased in the 200 mg/cm(3) BHC data. Errors averaged 8.2% across these samples and reached as high as 29.5%. Regression analyses suggested no size effects in the 1200 mg/cm(3) BHC data but differences between successive sizes still reached as high as 13%. The linear attenuation coefficients of the AL foams increased up to approximately 6% with increasing volume fractions (r(2)>0.81, p<0.05 for all) but the strength of the size-related error was also BHC dependent. Equivalent rho(m) values were inversely correlated with BCt cube size (r(2)>0.92, p<0.05). Use of the 1200 mg/cm(3) BHC ameliorated the size-related artifact compared to the 200 mg/cm(3) BHC but errors with this BHC were still significant and ranged between 5% and 12%. These results demonstrate that object size, structure, and BHC algorithm can influence microCT measurements of rho(m). Measurements of rho(m) of specimens of unequal size or quantities of bone mineral must be interpreted with caution unless appropriate steps are taken to minimize these potential artifacts.

  18. CT and MRI evaluation of skull bones and soft tissues in six cats with presumed acromegaly versus 12 unaffected cats.

    PubMed

    Fischetti, Anthony J; Gisselman, Kelly; Peterson, Mark E

    2012-01-01

    Feline acromegaly is predominantly caused by an adenoma of the pituitary gland, resulting in excessive growth hormone and insulin-like growth factor (IGF-1) secretion. In advanced cases, cats will display prominent facial features and upper airway congestion secondary to bony and soft tissue proliferation. The purpose of this study was to describe CT and MRI characteristics of soft tissues and skull bones in six cats with presumed acromegaly and to compare findings with those observed in 12 unaffected cats. In the five acromegalic cats with CT or MRI evidence of a pituitary tumor, frontal bone thickness was greater than age-matched controls with and without a history of upper airway disease. These five cats also had evidence of soft tissue accumulation in the nasal cavity, sinuses, and pharynx. One cat with insulin-resistant diabetes mellitus, elevated IGF-1, and a normal pituitary size did not have evidence of frontal bone thickening or upper airway congestion.

  19. Phase-contrast tomography of neuronal tissues: from laboratory- to high resolution synchrotron CT

    NASA Astrophysics Data System (ADS)

    Töpperwien, Mareike; Krenkel, Martin; Müller, Kristin; Salditt, Tim

    2016-10-01

    Assessing the three-dimensional architecture of neuronal tissues with sub-cellular resolution presents a significant analytical challenge. Overcoming the limitations associated with serial slicing, phase-contrast x-ray tomography has the potential to contribute to this goal. Even compact laboratory CT at an optimized liquid-metal jet micro- focus source combined with suitable phase-retrieval algorithms and preparation protocols can yield renderings with single cell sensitivity in millimeter sized brain areas of mouse. Here, we show the capabilities of the setup by imaging a Golgi-Cox impregnated mouse brain. Towards higher resolution we extend these studies at our recently upgraded waveguide-based cone-beam holo-tomography instrument GINIX at DESY. This setup allows high resolution recordings with adjustable field of view and resolution, down to the voxel sizes in the range of a few ten nanometers. The recent results make us confident that important issues of neuronal connectivity can be addressed by these methods, and that 3D (virtual) histology with nanoscale resolution will become an attractive modality for neuroscience research.

  20. Size effect of Au/PAMAM contrast agent on CT imaging of reticuloendothelial system and tumor tissue

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Li, Jian; Liu, Ransheng; Zhang, Aixu; Yuan, Zhiyong

    2016-09-01

    Polyamidoamine (PAMAM)-entrapped Au nanoparticles were synthesized with distinct sizes to figure out the size effect of Au-based contrast agent on CT imaging of passively targeted tissues. Au/PAMAM nanoparticles were first synthesized with narrow distribution of particles size of 22.2 ± 3.1, 54.2 ± 3.7, and 104.9 ± 4.7 nm in diameters. Size effect leads no significant difference on X-ray attenuation when Au/PAMAM was ≤0.05 mol/L. For CT imaging of a tumor model, small Au/PAMAM were more easily internalized via endocytosis in the liver, leading to more obviously enhanced contrast. Similarly, contrast agents with small sizes were more effective in tumor imaging because of the enhanced permeability and retention effect. Overall, the particle size of Au/PAMAM heavily affected the efficiency of CT enhancement in imaging RES and tumors.

  1. The use of CT density changes at internal tissue interfaces to correlate internal organ motion with an external surrogate

    NASA Astrophysics Data System (ADS)

    Gaede, Stewart; Carnes, Gregory; Yu, Edward; Van Dyk, Jake; Battista, Jerry; Lee, Ting-Yim

    2009-01-01

    The purpose of this paper is to describe a non-invasive method to monitor the motion of internal organs affected by respiration without using external markers or spirometry, to test the correlation with external markers, and to calculate any time shift between the datasets. Ten lung cancer patients were CT scanned with a GE LightSpeed Plus 4-Slice CT scanner operating in a ciné mode. We retrospectively reconstructed the raw CT data to obtain consecutive 0.5 s reconstructions at 0.1 s intervals to increase image sampling. We defined regions of interest containing tissue interfaces, including tumour/lung interfaces that move due to breathing on multiple axial slices and measured the mean CT number versus respiratory phase. Tumour motion was directly correlated with external marker motion, acquired simultaneously, using the sample coefficient of determination, r2. Only three of the ten patients showed correlation higher than r2 = 0.80 between tumour motion and external marker position. However, after taking into account time shifts (ranging between 0 s and 0.4 s) between the two data sets, all ten patients showed correlation better than r2 = 0.8. This non-invasive method for monitoring the motion of internal organs is an effective tool that can assess the use of external markers for 4D-CT imaging and respiratory-gated radiotherapy on a patient-specific basis.

  2. Brain tissue segmentation in PET-CT images using probabilistic atlas and variational Bayes inference.

    PubMed

    Xia, Yong; Wang, Jiabin; Eberl, Stefan; Fulham, Michael; Feng, David Dagan

    2011-01-01

    PET-CT provides aligned anatomical (CT) and functional (PET) images in a single scan, and has the potential to improve brain PET image segmentation, which can in turn improve quantitative clinical analyses. We propose a statistical segmentation algorithm that incorporates the prior anatomical knowledge represented by probabilistic brain atlas into the variational Bayes inference to delineate gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) in brain PET-CT images. Our approach adds an additional novel aspect by allowing voxels to have variable and adaptive prior probabilities of belonging to each class. We compared our algorithm to the segmentation approaches implemented in the expectation maximization segmentation (EMS) and statistical parametric mapping (SPM8) packages in 26 clinical cases. The results show that our algorithm improves the accuracy of brain PET-CT image segmentation.

  3. Automated quantitation of cold-inducible human brown adipose tissue with FDG PET/CT with application to fibromyalgia.

    PubMed

    Pardo, José V; Lee, Joel T; Larson, Robert C; Thuras, Paul; Larson, Alice A

    2017-01-01

    Increasing recognition of the importance of brown adipose tissue (BAT) motivates the development of reproducible and quantitative methods for measuring it. Positron emission tomography (PET)/computerized tomography (CT) with (18)F-fluorodeoxyglucose (FDG) has become the principal method to non-invasively detect brown adipose tissue (BAT) in humans. Improvements in quantitation and standardization will drive further clinical application. One disorder hypothesized to involve dysregulation in thermoregulation and the processing of pain involving BAT is fibromyalgia syndrome (FMS). This report describes an approach with additional technical standardization to measure cold-inducible, BAT activity (ci-BAT) semi-quantitatively and reliably with minimal operator intervention with the FDG PET/CT technique. Ci-BAT was measured to test whether FMS patients have decreased BAT activation compared to normal controls. Threshold parameters to optimally separate ci-BAT from non-ci-BAT were developed based on the distribution of the pixel-wise parametric data from each merged PET/CT scan for each study session occurring on different days. BAT activity was the same under warm conditions in both control and FMS subjects attesting to reproducibility and reliability. However, considerable variability arose between groups at cool temperatures consistent with other literature. Increases in ci-BAT activity were significantly less in FMS patients than in controls, as hypothesized. Ci-BAT recruitment can be quantified non-invasively using FDG PET/CT using semi-automated techniques in human subjects across different diagnostic groups or within groups undergoing manipulations of interest.

  4. Tumor and normal tissue motion in the thorax during respiration: Analysis of volumetric and positional variations using 4D CT

    SciTech Connect

    Weiss, Elisabeth . E-mail: eweiss@mcvh-vcu.edu; Wijesooriya, Krishni; Dill, S. Vaughn; Keall, Paul J.

    2007-01-01

    Purpose: To investigate temporospatial variations of tumor and normal tissue during respiration in lung cancer patients. Methods and Materials: In 14 patients, gross tumor volume (GTV) and normal tissue structures were manually contoured on four-dimensional computed tomography (4D-CT) scans. Structures were evaluated for volume changes, centroid (center of mass) motion, and phase dependence of variations relative to inspiration. Only volumetrically complete structures were used for analysis (lung in 2, heart in 8, all other structures in >10 patients). Results: During respiration, the magnitude of contoured volumes varied up to 62.5% for GTVs, 25.5% for lungs, and 12.6% for hearts. The range of maximum three-dimensional centroid movement for individual patients was 1.3-24.0 mm for GTV, 2.4-7.9 mm for heart, 5.2-12.0 mm for lungs, 0.3-5.5 mm for skin markers, 2.9-10.0 mm for trachea, and 6.6-21.7 mm for diaphragm. During respiration, the centroid positions of normal structures varied relative to the centroid position of the respective GTV by 1.5-8.1 mm for heart, 2.9-9.3 mm for lungs, 1.2-9.2 mm for skin markers, 0.9-7.1 mm for trachea, and 2.7-16.4 mm for diaphragm. Conclusion: Using 4D-CT, volumetric changes, positional alterations as well as changes in the position of contoured structures relative to the GTV were observed with large variations between individual patients. Although the interpretation of 4D-CT data has considerable uncertainty because of 4D-CT artifacts, observer variations, and the limited acquisition time, the findings might have a significant impact on treatment planning.

  5. Automated quantitation of cold-inducible human brown adipose tissue with FDG PET/CT with application to fibromyalgia

    PubMed Central

    Pardo, José V; Lee, Joel T; Larson, Robert C; Thuras, Paul; Larson, Alice A

    2017-01-01

    Increasing recognition of the importance of brown adipose tissue (BAT) motivates the development of reproducible and quantitative methods for measuring it. Positron emission tomography (PET)/computerized tomography (CT) with 18F-fluorodeoxyglucose (FDG) has become the principal method to non-invasively detect brown adipose tissue (BAT) in humans. Improvements in quantitation and standardization will drive further clinical application. One disorder hypothesized to involve dysregulation in thermoregulation and the processing of pain involving BAT is fibromyalgia syndrome (FMS). This report describes an approach with additional technical standardization to measure cold-inducible, BAT activity (ci-BAT) semi-quantitatively and reliably with minimal operator intervention with the FDG PET/CT technique. Ci-BAT was measured to test whether FMS patients have decreased BAT activation compared to normal controls. Threshold parameters to optimally separate ci-BAT from non-ci-BAT were developed based on the distribution of the pixel-wise parametric data from each merged PET/CT scan for each study session occurring on different days. BAT activity was the same under warm conditions in both control and FMS subjects attesting to reproducibility and reliability. However, considerable variability arose between groups at cool temperatures consistent with other literature. Increases in ci-BAT activity were significantly less in FMS patients than in controls, as hypothesized. Ci-BAT recruitment can be quantified non-invasively using FDG PET/CT using semi-automated techniques in human subjects across different diagnostic groups or within groups undergoing manipulations of interest. PMID:28123865

  6. Incorporating tissue excision in deformable image registration: a modified demons algorithm for cone-beam CT-guided surgery

    NASA Astrophysics Data System (ADS)

    Nithiananthan, S.; Mirota, D.; Uneri, A.; Schafer, S.; Otake, Y.; Stayman, J. W.; Siewerdsen, J. H.

    2011-03-01

    The ability to perform fast, accurate, deformable registration with intraoperative images featuring surgical excisions was investigated for use in cone-beam CT (CBCT) guided head and neck surgery. Existing deformable registration methods generally fail to account for tissue excised between image acquisitions and typically simply "move" voxels within the images with no ability to account for tissue that is removed (or introduced) between scans. We have thus developed an approach in which an extra dimension is added during the registration process to act as a sink for voxels removed during the course of the procedure. A series of cadaveric images acquired using a prototype CBCT-capable C-arm were used to model tissue deformation and excision occurring during a surgical procedure, and the ability of deformable registration to correctly account for anatomical changes under these conditions was investigated. Using a previously developed version of the Demons deformable registration algorithm, we identify the difficulties that traditional registration algorithms encounter when faced with excised tissue and present a modified version of the algorithm better suited for use in intraoperative image-guided procedures. Studies were performed for different deformation and tissue excision tasks, and registration performance was quantified in terms of the ability to accurately account for tissue excision while avoiding spurious deformations arising around the excision.

  7. Pulmonary fibrosis: tissue characterization using late-enhanced MRI compared with unenhanced anatomic high-resolution CT

    PubMed Central

    Lavelle, Lisa P.; Brady, Darragh; McEvoy, Sinead; Murphy, David; Gibney, Brian; Gallagher, Annika; Butler, Marcus; Shortt, Fionnula; McMullen, Marie; Fabre, Aurelie; Lynch, David A.; Keane, Michael P.; Dodd, Jonathan D.

    2017-01-01

    PURPOSE We aimed to prospectively evaluate anatomic chest computed tomography (CT) with tissue characterization late gadolinium-enhanced magnetic resonance imaging (MRI) in the evaluation of pulmonary fibrosis (PF). METHODS Twenty patients with idiopathic pulmonary fibrosis (IPF) and twelve control patients underwent late-enhanced MRI and high-resolution CT. Tissue characterization of PF was depicted using a segmented inversion-recovery turbo low-angle shot MRI sequence. Pulmonary arterial blood pool nulling was achieved by nulling main pulmonary artery signal. Images were read in random order by a blinded reader for presence and extent of overall PF (reticulation and honeycombing) at five anatomic levels. Overall extent of IPF was estimated to the nearest 5% as well as an evaluation of the ratios of IPF made up of reticulation and honeycombing. Overall grade of severity was dependent on the extent of reticulation and honeycombing. RESULTS No control patient exhibited contrast enhancement on lung late-enhanced MRI. All IPF patients were identified with late-enhanced MRI. Mean signal intensity of the late-enhanced fibrotic lung was 31.8±10.6 vs. 10.5±1.6 for normal lung regions, P < 0.001, resulting in a percent elevation in signal intensity from PF of 204.8%±90.6 compared with the signal intensity of normal lung. The mean contrast-to-noise ratio was 22.8±10.7. Late-enhanced MRI correlated significantly with chest CT for the extent of PF (R=0.78, P = 0.001) but not for reticulation, honeycombing, or coarseness of reticulation or honeycombing. CONCLUSION Tissue characterization of IPF is possible using inversion recovery sequence thoracic MRI. PMID:28067202

  8. Prognostic value of 18F-FDG PET-CT-based functional parameters in patients with soft tissue sarcoma

    PubMed Central

    Chen, Linyan; Wu, Xin; Ma, Xuelei; Guo, Linghong; Zhu, Chenjing; Li, Qingfang

    2017-01-01

    Abstract Background: Considering the clinical importance of high 5-year mortality, we performed a meta-analysis of maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) from 18F-FDG PET-CT for overall survival (OS) and progression-free survival (PFS) in patients with soft tissue sarcoma. Methods: The search and selection of eligible articles was conducted on PubMed and EMBASE. We applied hazard ratio (HR) and odd ratio (OR) to measure the correlation between SUVmax, MTV, and TLG with PFS and OS. The SUVmax was analyzed through subgroup in terms of histological grade and HR of posttreatment SUVmax was also assessed. Results: Eleven studies with 582 patients were included. The pooled HRs of pretreatment SUVmax were 2.40 (95% CI: 1.38–4.17) for OS and 2.20 (95% CI: 1.47–3.30) for PFS. The HRs in terms of OS were 3.20 (95% CI: 1.71–5.98) based on MTV and 5.20 (95% CI: 2.34–11.56) based on TLG. Meanwhile, the predict results of pretreatment SUVmax on OR remained significant and the HRs of posttreatment SUVmax were 2.25 (95% CI: 1.33–3.80) for OS and 2.87 (95% CI: 1.81–4.55) for PFS. Conclusions: The pretreatment SUVmax, MTV, and TLG of 18F-FDG PET-CT showed significant prognostic value for OS and the PET-CT can be used in identifying high-risk patients about progression and survival. The analysis for posttreatment SUVmax suggested PET-CT as a promising equipment in monitoring therapy response. PMID:28178131

  9. High resolution multidetector CT aided tissue analysis and quantification of lung fibrosis

    NASA Astrophysics Data System (ADS)

    Zavaletta, Vanessa A.; Karwoski, Ronald A.; Bartholmai, Brian; Robb, Richard A.

    2006-03-01

    Idiopathic pulmonary fibrosis (IPF, also known as Idiopathic Usual Interstitial Pneumontis, pathologically) is a progressive diffuse lung disease which has a median survival rate of less than four years with a prevalence of 15-20/100,000 in the United States. Global function changes are measured by pulmonary function tests and the diagnosis and extent of pulmonary structural changes are typically assessed by acquiring two-dimensional high resolution CT (HRCT) images. The acquisition and analysis of volumetric high resolution Multi-Detector CT (MDCT) images with nearly isotropic pixels offers the potential to measure both lung function and structure. This paper presents a new approach to three dimensional lung image analysis and classification of normal and abnormal structures in lungs with IPF.

  10. Iodine-enhanced micro-CT imaging: methodological refinements for the study of the soft-tissue anatomy of post-embryonic vertebrates.

    PubMed

    Gignac, Paul M; Kley, Nathan J

    2014-05-01

    The now widespread use of non-destructive X-ray computed tomography (CT) and micro-CTCT) has greatly augmented our ability to comprehensively detail and quantify the internal hard-tissue anatomy of vertebrates. However, the utility of X-ray imaging for gaining similar insights into vertebrate soft-tissue anatomy has yet to be fully realized due to the naturally low X-ray absorption of non-mineralized tissues. In this study, we show how a wide diversity of soft-tissue structures within the vertebrate head-including muscles, glands, fat deposits, perichondria, dural venous sinuses, white and gray matter of the brain, as well as cranial nerves and associated ganglia-can be rapidly visualized in their natural relationships with extraordinary levels of detail using iodine-enhanced (i-e) µCT imaging. To date, Lugol's iodine solution (I2 KI) has been used as a contrast agent for µCT imaging of small invertebrates, vertebrate embryos, and certain isolated parts of larger, post-embryonic vertebrates. These previous studies have all yielded promising results, but visualization of soft tissues in smaller invertebrate and embryonic vertebrate specimens has generally been more complete than that for larger, post-embryonic vertebrates. Our research builds on these previous studies by using high-energy µCT together with more highly concentrated I2 KI solutions and longer staining times to optimize the imaging and differentiation of soft tissues within the heads of post-embryonic archosaurs (Alligator mississippiensis and Dromaius novaehollandiae). We systematically quantify the intensities of tissue staining, demonstrate the range of anatomical structures that can be visualized, and generate a partial three-dimensional reconstruction of alligator cephalic soft-tissue anatomy.

  11. A correlative method for imaging identical regions of samples by micro-CT, light microscopy, and electron microscopy: imaging adipose tissue in a model system.

    PubMed

    Sengle, Gerhard; Tufa, Sara F; Sakai, Lynn Y; Zulliger, Martin A; Keene, Douglas R

    2013-04-01

    We present a method in which a precise region of interest within an intact organism is spatially mapped in three dimensions by non-invasive micro-computed X-ray tomography (micro-CT), then further evaluated by light microscopy (LM) and transmission electron microscopy (TEM). Tissues are prepared as if for TEM including osmium fixation, which imparts soft tissue contrast in the micro-CT due to its strong X-ray attenuation. This method may therefore be applied to embedded, archived TEM samples. Upon selection of a two-dimensional (2-D) projection from a region of interest (ROI) within the three-dimensional volume, the epoxy-embedded sample is oriented for microtomy so that the sectioning plane is aligned with the micro-CT projection. Registration is verified by overlaying LM images with 2-D micro-CT projections. Structures that are poorly resolved in the micro-CT may be evaluated at TEM resolution by observing the next serial ultrathin section, thereby accessing the same ROI by all three imaging techniques. We compare white adipose tissue within the forelimbs of mice harboring a lipid-altering mutation with their littermate controls. We demonstrate that individual osmium-stained lipid droplets as small as 15 µm and separated by as little as 35 µm may be discerned as separate entities in the micro-CT, validating this to be a high-resolution, non-destructive technique for evaluation of fat content.

  12. CT-soft tissue window of the cranial abdomen in clinically normal dogs: an anatomical description using macroscopic cross-sections with vascular injection.

    PubMed

    Rivero, M A; Vázquez, J M; Gil, F; Ramírez, J A; Vilar, J M; De Miguel, A; Arencibia, A

    2009-02-01

    The aim of this study was to provide a detailed anatomic atlas of the cranial abdomen by means of computed tomography (CT). Three mature dogs, all mixed breed males, were used. The dogs were sedated, anaesthetized and positioned in sternal recumbency. CT scans from the eighth thoracic vertebra to the fourth lumbar vertebra were performed using a third-generation equipment (TOSHIBA 600HQ scanner) with 1 cm slice thickness. CT-images of the cranial abdomen were taken with soft-tissue window (WL: -14, WW: 658) settings. Dogs were killed and vascular-injection technique was performed: red and blue latex filled the vascular system. Injected dogs were frozen in the same position as used for CT examination and sectioned with an electric bandsaw at 1-cm-thick intervals. The cuts matched as closely as possible to the CT-images. The anatomic sections were compared and studied with the corresponding CT-images, and clinically relevant abdominal anatomic structures were identified and labelled on the corresponding CT-images. The results of our study could be used as a reference for evaluating CT-images of the canine cranial abdomen with abdominal diseases.

  13. Correlative Imaging of the Murine Hind Limb Vasculature and Muscle Tissue by MicroCT and Light Microscopy

    PubMed Central

    Schaad, Laura; Hlushchuk, Ruslan; Barré, Sébastien; Gianni-Barrera, Roberto; Haberthür, David; Banfi, Andrea; Djonov, Valentin

    2017-01-01

    A detailed vascular visualization and adequate quantification is essential for the proper assessment of novel angiomodulating strategies. Here, we introduce an ex vivo micro-computed tomography (microCT)-based imaging approach for the 3D visualization of the entire vasculature down to the capillary level and rapid estimation of the vascular volume and vessel size distribution. After perfusion with μAngiofil®, a novel polymerizing contrast agent, low- and high-resolution scans (voxel side length: 2.58–0.66 μm) of the entire vasculature were acquired. Based on the microCT data, sites of interest were defined and samples further processed for correlative morphology. The solidified, autofluorescent μAngiofil® remained in the vasculature and allowed co-registering of the histological sections with the corresponding microCT-stack. The perfusion efficiency of μAngiofil® was validated based on lectin-stained histological sections: 98 ± 0.5% of the blood vessels were μAngiofil®-positive, whereas 93 ± 2.6% were lectin-positive. By applying this approach we analyzed the angiogenesis induced by the cell-based delivery of a controlled VEGF dose. Vascular density increased by 426% mainly through the augmentation of medium-sized vessels (20–40 μm). The introduced correlative and quantitative imaging approach is highly reproducible and allows a detailed 3D characterization of the vasculature and muscle tissue. Combined with histology, a broad range of complementary structural information can be obtained. PMID:28169309

  14. 3D imaging of lung tissue by confocal microscopy and micro-CT

    NASA Astrophysics Data System (ADS)

    Kriete, Andres; Breithecker, Andreas; Rau, Wigbert D.

    2001-07-01

    Two complementary techniques for the imaging of tissue subunits are discussed. A computer guided light microscopic imaging technique is described first, which confocally resolves thick serial sections axially. The lateral area of interest is increased by scanning a mosaic of images in each plane. Subsequently, all images are fused digitally to form a highly resolved volume exhibiting the fine structure of complete respiratory units of lung. A different technique described is based on microtomography. This method allows to image volumes up to 3x3x3 cm at a resolution of up to 7 microns. Due to the lack of strong density differences, a contrast enhancement procedure is introduced which makes this technique applicable for the imaging of lung tissue. Imaging, visualization and analysis described here are parts of an ongoing project to model structure and to simulate function of tissue subunits and complete organs.

  15. Development of virtual patient models for permanent implant brachytherapy Monte Carlo dose calculations: interdependence of CT image artifact mitigation and tissue assignment

    NASA Astrophysics Data System (ADS)

    Miksys, N.; Xu, C.; Beaulieu, L.; Thomson, R. M.

    2015-08-01

    This work investigates and compares CT image metallic artifact reduction (MAR) methods and tissue assignment schemes (TAS) for the development of virtual patient models for permanent implant brachytherapy Monte Carlo (MC) dose calculations. Four MAR techniques are investigated to mitigate seed artifacts from post-implant CT images of a homogeneous phantom and eight prostate patients: a raw sinogram approach using the original CT scanner data and three methods (simple threshold replacement (STR), 3D median filter, and virtual sinogram) requiring only the reconstructed CT image. Virtual patient models are developed using six TAS ranging from the AAPM-ESTRO-ABG TG-186 basic approach of assigning uniform density tissues (resulting in a model not dependent on MAR) to more complex models assigning prostate, calcification, and mixtures of prostate and calcification using CT-derived densities. The EGSnrc user-code BrachyDose is employed to calculate dose distributions. All four MAR methods eliminate bright seed spot artifacts, and the image-based methods provide comparable mitigation of artifacts compared with the raw sinogram approach. However, each MAR technique has limitations: STR is unable to mitigate low CT number artifacts, the median filter blurs the image which challenges the preservation of tissue heterogeneities, and both sinogram approaches introduce new streaks. Large local dose differences are generally due to differences in voxel tissue-type rather than mass density. The largest differences in target dose metrics (D90, V100, V150), over 50% lower compared to the other models, are when uncorrected CT images are used with TAS that consider calcifications. Metrics found using models which include calcifications are generally a few percent lower than prostate-only models. Generally, metrics from any MAR method and any TAS which considers calcifications agree within 6%. Overall, the studied MAR methods and TAS show promise for further retrospective MC dose

  16. SU-D-12A-02: DeTECT, a Method to Enhance Soft Tissue Contrast From Mega Voltage CT

    SciTech Connect

    Sheng, K; Gou, S; Qi, S

    2014-06-01

    Purpose: MVCT images have been used on TomoTherapy system to align patients based on bony anatomies but its usefulness for soft tissue registration, delineation and adaptive radiation therapy is severely limited due to minimal photoelectric interaction and prominent presence of noise resulting from low detector quantum efficiency of megavoltage x-rays. We aim to utilize a non-local means denoising method and texture analysis to recover the soft tissue information for MVCT. Methods: A block matching 3D (BM3D) algorithm was adapted to reduce the noise while keeping the texture information of the MVCT images. BM3D is an imaging denoising algorithm developed from non-local means methods. BM3D additionally creates 3D groups by stacking 2D patches by the order of similarity. 3D denoising operation is then performed. The resultant 3D group is inversely transformed back to 2D images. In this study, BM3D was applied to MVCT images of a CT quality phantom, a head and neck and a prostate patient. Following denoising, imaging texture was enhanced to create the denoised and texture enhanced CT (DeTECT). Results: The original MVCT images show prevalent noise and poor soft tissue contrast. By applying BM3D denoising and texture enhancement, all MVCT images show remarkable improvements. For the phantom, the contrast to noise ratio for the low contrast plug was improved from 2.2 to 13.1 without compromising line pair conspicuity. For the head and neck patient, the lymph nodes and vein in the carotid space inconspicuous in the original MVCT image becomes highly visible in DeTECT. For the prostate patient, the boundary between the bladder and the prostate in the original MVCT is successfully recovered. Both results are visually validated by kVCT images of the corresponding patients. Conclusion: DeTECT showed the promise to drastically improve the soft tissue contrast of MVCT for image guided radiotherapy and adaptive radiotherapy.

  17. Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy

    NASA Astrophysics Data System (ADS)

    Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, George; Thieke, Christian; Würl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Jürgen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

    2017-03-01

    The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β + activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECTdist). The method was also applied to SECT data (SECTdist). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECTdist and SECTdist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECTSchneider). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECTdist and 0.54, 0.41 and 0.66 for SECTdist. MC simulations of PET treatment verification in patients showed important differences between DECTdist/SECTdist and SECTSchneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECTdist and SECTdist yielded comparable activity distributions, and comparison of SECTdist to a measured patient PET scan showed improved agreement when compared to SECTSchneider. The agreement between predicted and measured PET

  18. MO-F-CAMPUS-J-05: Toward MRI-Only Radiotherapy: Novel Tissue Segmentation and Pseudo-CT Generation Techniques Based On T1 MRI Sequences

    SciTech Connect

    Aouadi, S; McGarry, M; Hammoud, R; Torfeh, T; Perkins, G; Al-Hammadi, N

    2015-06-15

    Purpose: To develop and validate a 4 class tissue segmentation approach (air cavities, background, bone and soft-tissue) on T1 -weighted brain MRI and to create a pseudo-CT for MRI-only radiation therapy verification. Methods: Contrast-enhanced T1-weighted fast-spin-echo sequences (TR = 756ms, TE= 7.152ms), acquired on a 1.5T GE MRI-Simulator, are used.MRIs are firstly pre-processed to correct for non uniformity using the non parametric, non uniformity intensity normalization algorithm. Subsequently, a logarithmic inverse scaling log(1/image) is applied, prior to segmentation, to better differentiate bone and air from soft-tissues. Finally, the following method is enrolled to classify intensities into air cavities, background, bone and soft-tissue:Thresholded region growing with seed points in image corners is applied to get a mask of Air+Bone+Background. The background is, afterward, separated by the scan-line filling algorithm. The air mask is extracted by morphological opening followed by a post-processing based on knowledge about air regions geometry. The remaining rough bone pre-segmentation is refined by applying 3D geodesic active contours; bone segmentation evolves by the sum of internal forces from contour geometry and external force derived from image gradient magnitude.Pseudo-CT is obtained by assigning −1000HU to air and background voxels, performing linear mapping of soft-tissue MR intensities in [-400HU, 200HU] and inverse linear mapping of bone MR intensities in [200HU, 1000HU]. Results: Three brain patients having registered MRI and CT are used for validation. CT intensities classification into 4 classes is performed by thresholding. Dice and misclassification errors are quantified. Correct classifications for soft-tissue, bone, and air are respectively 89.67%, 77.8%, and 64.5%. Dice indices are acceptable for bone (0.74) and soft-tissue (0.91) but low for air regions (0.48). Pseudo-CT produces DRRs with acceptable clinical visual agreement to CT

  19. A navigation system for percutaneous needle interventions based on PET/CT images: design, workflow and error analysis of soft tissue and bone punctures.

    PubMed

    Oliveira-Santos, Thiago; Klaeser, Bernd; Weitzel, Thilo; Krause, Thomas; Nolte, Lutz-Peter; Peterhans, Matthias; Weber, Stefan

    2011-01-01

    Percutaneous needle intervention based on PET/CT images is effective, but exposes the patient to unnecessary radiation due to the increased number of CT scans required. Computer assisted intervention can reduce the number of scans, but requires handling, matching and visualization of two different datasets. While one dataset is used for target definition according to metabolism, the other is used for instrument guidance according to anatomical structures. No navigation systems capable of handling such data and performing PET/CT image-based procedures while following clinically approved protocols for oncologic percutaneous interventions are available. The need for such systems is emphasized in scenarios where the target can be located in different types of tissue such as bone and soft tissue. These two tissues require different clinical protocols for puncturing and may therefore give rise to different problems during the navigated intervention. Studies comparing the performance of navigated needle interventions targeting lesions located in these two types of tissue are not often found in the literature. Hence, this paper presents an optical navigation system for percutaneous needle interventions based on PET/CT images. The system provides viewers for guiding the physician to the target with real-time visualization of PET/CT datasets, and is able to handle targets located in both bone and soft tissue. The navigation system and the required clinical workflow were designed taking into consideration clinical protocols and requirements, and the system is thus operable by a single person, even during transition to the sterile phase. Both the system and the workflow were evaluated in an initial set of experiments simulating 41 lesions (23 located in bone tissue and 18 in soft tissue) in swine cadavers. We also measured and decomposed the overall system error into distinct error sources, which allowed for the identification of particularities involved in the process as well

  20. Volume and tissue composition preserving deformation of breast CT images to simulate breast compression in mammographic imaging

    NASA Astrophysics Data System (ADS)

    Han, Tao; Chen, Lingyun; Lai, Chao-Jen; Liu, Xinming; Shen, Youtao; Zhong, Yuncheng; Ge, Shuaiping; Yi, Ying; Wang, Tianpeng; Shaw, Chris C.

    2009-02-01

    Images of mastectomy breast specimens have been acquired with a bench top experimental Cone beam CT (CBCT) system. The resulting images have been segmented to model an uncompressed breast for simulation of various CBCT techniques. To further simulate conventional or tomosynthesis mammographic imaging for comparison with the CBCT technique, a deformation technique was developed to convert the CT data for an uncompressed breast to a compressed breast without altering the breast volume or regional breast density. With this technique, 3D breast deformation is separated into two 2D deformations in coronal and axial views. To preserve the total breast volume and regional tissue composition, each 2D deformation step was achieved by altering the square pixels into rectangular ones with the pixel areas unchanged and resampling with the original square pixels using bilinear interpolation. The compression was modeled by first stretching the breast in the superior-inferior direction in the coronal view. The image data were first deformed by distorting the voxels with a uniform distortion ratio. These deformed data were then deformed again using distortion ratios varying with the breast thickness and re-sampled. The deformation procedures were applied in the axial view to stretch the breast in the chest wall to nipple direction while shrinking it in the mediolateral to lateral direction re-sampled and converted into data for uniform cubic voxels. Threshold segmentation was applied to the final deformed image data to obtain the 3D compressed breast model. Our results show that the original segmented CBCT image data were successfully converted into those for a compressed breast with the same volume and regional density preserved. Using this compressed breast model, conventional and tomosynthesis mammograms were simulated for comparison with CBCT.

  1. Reproducibility of facial soft tissue thicknesses for craniofacial reconstruction using cone-beam CT images.

    PubMed

    Hwang, Hyeon-Shik; Kim, Kyul; Moon, Da-Nal; Kim, Jae-Hyung; Wilkinson, Caroline

    2012-03-01

    The purpose of this study was to evaluate the reproducibility of the soft tissue (ST) thicknesses at 31 landmarks using the cone-beam computed tomography (CBCT) images obtained from 20 adult subjects. Four observers carried out ST thickness measurements using Skull Measure software, and the inter- and intra-observer error rates were evaluated. Only five of 31 landmarks showed significant differences in recorded ST thickness between the observers. When excluding inexperienced observers, only one landmark showed a significant difference between the observers. Regarding the intra-observer reproducibility, the ST thickness measurements at three landmarks showed low correlation coefficients. The results of this study indicate that CBCT images can be used to measure ST thickness with high reproducibility. However, some landmarks need to be redefined to reliably measure ST thickness on CBCT images.

  2. Deriving concentrations of oxygen and carbon in human tissues using single- and dual-energy CT for ion therapy applications

    NASA Astrophysics Data System (ADS)

    Landry, Guillaume; Parodi, Katia; Wildberger, Joachim E.; Verhaegen, Frank

    2013-08-01

    Dedicated methods of in-vivo verification of ion treatment based on the detection of secondary emitted radiation, such as positron-emission-tomography and prompt gamma detection require high accuracy in the assignment of the elemental composition. This especially concerns the content in carbon and oxygen, which are the most abundant elements of human tissue. The standard single-energy computed tomography (SECT) approach to carbon and oxygen concentration determination has been shown to introduce significant discrepancies in the carbon and oxygen content of tissues. We propose a dual-energy CT (DECT)-based approach for carbon and oxygen content assignment and investigate the accuracy gains of the method. SECT and DECT Hounsfield units (HU) were calculated using the stoichiometric calibration procedure for a comprehensive set of human tissues. Fit parameters for the stoichiometric calibration were obtained from phantom scans. Gaussian distributions with standard deviations equal to those derived from phantom scans were subsequently generated for each tissue for several values of the computed tomography dose index (CTDIvol). The assignment of %weight carbon and oxygen (%wC,%wO) was performed based on SECT and DECT. The SECT scheme employed a HU versus %wC,O approach while for DECT we explored a Zeff versus %wC,O approach and a (Zeff, ρe) space approach. The accuracy of each scheme was estimated by calculating the root mean square (RMS) error on %wC,O derived from the input Gaussian distribution of HU for each tissue and also for the noiseless case as a limiting case. The (Zeff, ρe) space approach was also compared to SECT by comparing RMS error for hydrogen and nitrogen (%wH,%wN). Systematic shifts were applied to the tissue HU distributions to assess the robustness of the method against systematic uncertainties in the stoichiometric calibration procedure. In the absence of noise the (Zeff, ρe) space approach showed more accurate %wC,O assignment (largest error of

  3. Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy.

    PubMed

    Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, Georgios; Thieke, Christian; Wuerl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Juergen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

    2017-02-09

    The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β+ activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECTdist). The method was also applied to SECT data (SECTdist). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECTdist and SECTdist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECTSchneider). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECTdist and 0.54, 0.41 and 0.66 for SECTdist. MC simulations of PET treatment verification in patients showed important differences between DECTdist/SECTdist and SECTSchneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECTdist and SECTdist yielded comparable activity distributions, and comparison of SECT

  4. 2D beam hardening correction for micro-CT of immersed hard tissue

    NASA Astrophysics Data System (ADS)

    Davis, Graham; Mills, David

    2016-10-01

    Beam hardening artefacts arise in tomography and microtomography with polychromatic sources. Typically, specimens appear to be less dense in the center of reconstructions because as the path length through the specimen increases, so the X-ray spectrum is shifted towards higher energies due to the preferential absorption of low energy photons. Various approaches have been taken to reduce or correct for these artefacts. Pre-filtering the X-ray beam with a thin metal sheet will reduce soft energy X-rays and thus narrow the spectrum. Correction curves can be applied to the projections prior to reconstruction which transform measured attenuation with polychromatic radiation to predicted attenuation with monochromatic radiation. These correction curves can be manually selected, iteratively derived from reconstructions (this generally works where density is assumed to be constant) or derived from a priori information about the X-ray spectrum and specimen composition. For hard tissue specimens, the latter approach works well if the composition is reasonably homogeneous. In the case of an immersed or embedded specimen (e.g., tooth or bone) the relative proportions of mineral and "organic" (including medium and plastic container) species varies considerably for different ray paths and simple beam hardening correction does not give accurate results. By performing an initial reconstruction, the total path length through the container can be determined. By modelling the X-ray properties of the specimen, a 2D correction transform can then be created such that the predicted monochromatic attenuation can be derived as a function of both the measured polychromatic attenuation and the container path length.

  5. Texture analysis of non-contrast enhanced CT for assessing angiogenesis and survival of soft tissue sarcoma

    PubMed Central

    Hayano, Koichi; Tian, Fang; Kambadakone, Avinash R.; Yoon, Sam S.; Duda, Dan G; Ganeshan, Balaji; Sahani, Dushyant V.

    2015-01-01

    Objective To evaluate the role of computed tomographic texture analysis (CTTA) in assessing tumor angiogenesis and survival of soft tissue sarcoma (STS). Methods In twenty patients with STSs, tumor texture parameters, which were measured on pre-therapeutic CT using CTTA software with the spatial scale filter (SSF) extracting fine to coarse texture, were compared with microvessel density (MVD), plasma VEGF, soluble VEGF receptor-1 (sVEGFR-1), and overall survival (OS). Results Mean of positive pixels (MPP) showed a positive correlation with MVD (P=0.02). Entropy at medium texture scales (SSF=3,4,5) showed positive correlations with VEGF (P=0.03, P=0.009, P=0.02, respectively), and entropy without filtration showed a positive correlation with sVEGFR-1 (P=0.02). In univariate analysis, kurtosis at a medium texture scale and MPP showed significant correlations with OS (P=0.04, P=0.007), and multivariate analysis demonstrated that MPP was an independent prognostic factor (P=0.01). Conclusion Texture parameters are associated with tumor angiogenesis and OS in STS. PMID:25793653

  6. Topical contrast agents to improve soft-tissue contrast in the upper airway using cone beam CT: a pilot study.

    PubMed

    Alsufyani, N A; Noga, M L; Finlay, W H; Major, P W

    2013-01-01

    The purpose of this study is to explore the topical use of radiographic contrast agents to enhance soft-tissue contrast on cone beam CT (CBCT) images. Different barium sulphate concentrations were first tested using an airway phantom. Different methods of barium sulphate application (nasal drops, syringe, spray and sinus wash) were then tested on four volunteers, and nebulized iodine was tested in one volunteer. CBCT images were performed and then assessed subjectively by two examiners for contrast agent uniformity and lack of streak artefact. 25.0% barium sulphate presented adequate viscosity and radiodensity. Barium sulphate administered via nasal drops and sprays showed non-uniform collection at the nostrils, along the inferior and/or middle nasal meatuses and posterior nasal choana. The syringe and sinus wash showed similar results with larger volumes collecting in the naso-oropharynx. Nebulized iodine failed to distribute into the nasal cavity and scarcely collected at the nostrils. All methods of nasal application failed to adequately reach or uniformly coat the nasal cavity beyond the inferior nasal meatuses. The key factors to consider for optimum topical radiographic contrast in the nasal airway are particle size, flow velocity and radio-opacity.

  7. Correlation of biomechanics to tissue reaction in aortic aneurysms assessed by finite elements and [18F]-fluorodeoxyglucose-PET/CT.

    PubMed

    Maier, Andreas; Essler, Markus; Gee, Michael W; Eckstein, Hans-Henning; Wall, Wolfgang A; Reeps, Christian

    2012-04-01

    Mechanobiological interactions are essential for the adaption of the cardiovascular system to altered environmental and internal conditions, but are poorly understood with regard to abdominal aortic aneurysm (AAA) pathogenesis, growth and rupture. In the present study, we therefore calculated mechanical AAA quantities using nonlinear finite element methods and correlated these to [18F]-fluorodeoxyglucose (FDG)-metabolic activity in the AAA wall detected by positron emission tomography/computed tomography (PET/CT). The interplay between mechanics and FDG-metabolic activity was analyzed in terms of maximum values and the three-dimensional spatial relationship, respectively. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) data sets of n = 18 AAA patients were studied. Maximum FDG-uptake (SUV max ) in the AAA wall varied from 1.32 to 4.60 (average SUV max 3.31 ± 0.87). Maximum wall stresses and strains ranged from 10.0 to 64.0 N∕cm(2) (38.2 ± 13.8  N∕cm(2)) and from 0.190 to 0.260 (0.222 ± 0.023), respectively. SUV max was significantly correlated to maximum wall stress and strain (SUV max to stress: r = 0.71, p = 0.0005; SUV max to strain: r = 0.66, p = 0.0013). To evaluate the three-dimensional spatial interaction between FDG-uptake and acting wall stress, element-wise correlations were performed. In all but 2 AAAs, positive element-wise correlation of FDG-uptake to wall stress was obtained, with the Pearson's correlation coefficient ranging from -0.168 to 0.738 ( 0.372 ± 0.263). The results indicate that mechanical stresses are correlated quantitatively and spatially to FDG-uptake in the AAA wall. It is hypothesized that unphysiologically increased loading in the AAA wall triggers biological tissue reaction, such as inflammation or regenerative processes, causing elevated FDG-metabolic activity. These findings strongly support experimental hypotheses of mechanotransduction mechanisms in vivo.

  8. Evaluating differential nuclear DNA yield rates and osteocyte numbers among human bone tissue types: A synchrotron radiation micro-CT approach.

    PubMed

    Andronowski, Janna M; Mundorff, Amy Z; Pratt, Isaac V; Davoren, Jon M; Cooper, David M L

    2017-05-01

    Molecular human identification has conventionally focused on DNA sampling from dense, weight-bearing cortical bone tissue, typically from femora or tibiae. A comparison of skeletal elements from three contemporary individuals demonstrated that elements with high quantities of cancellous bone yielded nuclear DNA at the highest rates, suggesting that preferentially sampling cortical bone may be suboptimal (Mundorff & Davoren, 2014). Despite these findings, the reason for the differential DNA yields between cortical and cancellous bone tissues remains unknown. The primary goal of this work is to ascertain whether differences in bone microstructure can be used to explain differential nuclear DNA yield among bone tissue types observed by Mundorff and Davoren (2014), with a focus on osteocytes and the three-dimensional (3D) quantification of their associated lacunae. Osteocytes and other bone cells are recognized to house DNA in bone tissue, thus examining the density of their lacunae may explain why nuclear DNA yield rates differ among bone tissue types. Lacunae were visualized and quantified using synchrotron radiation-based micro-Computed Tomographic imaging (SR micro-CT). Volumes of interest (VOIs) from cortical and cancellous bone tissues (n=129) were comparatively analyzed from the three skeletons sampled for Mundorff and Davoren's (2014) study. Analyses tested the primary hypothesis that the abundance and density of osteocytes (inferred from their lacunar spaces) vary between cortical and cancellous bone tissue types. Results demonstrated that osteocyte lacunar abundance and density vary between cortical and cancellous bone tissue types, with cortical bone VOIs containing a higher lacunar abundance and density. We found that the osteocyte lacunar density values are independent of nuclear DNA yield, suggesting an alternative explanation for the higher nuclear DNA yields from bones with greater quantities of cancellous bone tissue. The use of SR micro-CT allowed for

  9. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues.

    PubMed

    Gignac, Paul M; Kley, Nathan J; Clarke, Julia A; Colbert, Matthew W; Morhardt, Ashley C; Cerio, Donald; Cost, Ian N; Cox, Philip G; Daza, Juan D; Early, Catherine M; Echols, M Scott; Henkelman, R Mark; Herdina, A Nele; Holliday, Casey M; Li, Zhiheng; Mahlow, Kristin; Merchant, Samer; Müller, Johannes; Orsbon, Courtney P; Paluh, Daniel J; Thies, Monte L; Tsai, Henry P; Witmer, Lawrence M

    2016-06-01

    Morphologists have historically had to rely on destructive procedures to visualize the three-dimensional (3-D) anatomy of animals. More recently, however, non-destructive techniques have come to the forefront. These include X-ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard-tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT-based research is the use of chemical agents to render visible, and differentiate between, soft-tissue structures in X-ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine-based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine-based, contrast-enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting-edge applications of diffusible iodine-based contrast-enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.

  10. Pilot Study to Confirm that Fat and Liver can be Distinguished by Spectroscopic Tissue Response on a Medipix-All-Resolution System-CT (MARS-CT)

    SciTech Connect

    Berg, Kyra B.; Anderson, Nigel G.; Butler, Alexandra P.; Carr, James M.; Clark, Michael J.; Cook, Nick J.; Scott, Nicola J.; Butler, Philip H.; Butler, Anthony P.

    2009-07-23

    NAFLD, liver component of the 'metabolic' syndrome, has become the most common liver disease in western nations. Non-invasive imaging techniques exist, but have limitations, especially in detection and quantification of mild to moderate fatty liver. In this pilot study, we produced attenuation curves from biomedical-quality projection images of liver and fat using the MARS spectroscopic-CT scanner. Difficulties obtaining attenuation spectra after reconstruction demonstrated that standard reconstruction programs do not preserve spectral information.

  11. Pilot Study to Confirm that Fat and Liver can be Distinguished by Spectroscopic Tissue Response on a Medipix-All-Resolution System-CT (MARS-CT)

    NASA Astrophysics Data System (ADS)

    Berg, Kyra B.; Carr, James M.; Clark, Michael J.; Cook, Nick J.; Anderson, Nigel G.; Scott, Nicola J.; Butler, Alexandra P.; Butler, Philip H.; Butler, Anthony P.

    2009-07-01

    NAFLD, liver component of the "metabolic" syndrome, has become the most common liver disease in western nations. Non-invasive imaging techniques exist, but have limitations, especially in detection and quantification of mild to moderate fatty liver. In this pilot study, we produced attenuation curves from biomedical-quality projection images of liver and fat using the MARS spectroscopic-CT scanner. Difficulties obtaining attenuation spectra after reconstruction demonstrated that standard reconstruction programs do not preserve spectral information.

  12. SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

    SciTech Connect

    Steinmann, A; Stafford, R; Yung, J; Followill, D

    2015-06-15

    Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR. Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials.

  13. 18F-NaF PET/CT in Extensive Melorheostosis of the Axial and Appendicular Skeleton With Soft-Tissue Involvement.

    PubMed

    Papadakis, Georgios Z; Jha, Smita; Bhattacharyya, Timothy; Millo, Corina; Tu, Tsang-Wei; Bagci, Ulas; Marias, Kostas; Karantanas, Apostolos H; Patronas, Nicholas J

    2017-03-17

    Melorheostosis is a rare, nonhereditary, benign, sclerotic bone dysplasia with no sex predilection, typically occurring in late childhood or early adulthood, which can lead to substantial functional morbidity, depending on the sites of involvement. We report on a patient with extensive melorheostosis in the axial and appendicular skeleton, as well as in the soft tissues, who was evaluated with whole-body F-NaF PET/CT scan. All melorheostotic lesions of the skeleton and of the ossified soft-tissue masses demonstrated intensely increased F-NaF activity, suggesting the application of this modality in assessing and monitoring the disease activity.

  14. Mapping transitions between healthy and pathological lesions in human breast tissues by diffraction enhanced imaging computed tomography (DEI-CT) and small angle x-ray scattering (SAXS)

    NASA Astrophysics Data System (ADS)

    Conceição, A. L. C.; Antoniassi, M.; Geraldelli, W.; Poletti, M. E.

    2014-02-01

    In this work we have combined the DEI-CT and SAXS technique to study the transition between healthy and pathological breast tissues, which include benign and malignant lesions. The ability of DEI-CT to enhance the contrast between soft tissues was used to localize the tumor region in the sample. Then, the tumor region and its surroundings were scanned by SAXS in order to map the changes promoted by the neoplasias at nano-level.It was clearly observed that pathological tissues present distinguishable SAXS scattering profiles from those of normal tissue. These differences are mainly related to changes in arrangement and diameter of collagen fibrils, evaluated by the higher order of reflection peaks of these fibrils. Differences related to the peak intensities and the total scattered intensity were found by comparing the healthy and pathological regions. The 2nd order of collagen reflection arises only in the healthy region neighboring the benign lesion. A broader peak at q=0.16 nm-1 seems to characterize the malignant lesions. Finally, based on this information, the transition between healthy and pathological human breast tissues was mapped which allowed to get insights into the changes promoted by tumors during growth and progression.

  15. The Value of SPECT/CT in Monitoring Prefabricated Tissue-Engineered Bone and Orthotopic rhBMP-2 Implants for Mandibular Reconstruction

    PubMed Central

    Zhou, Miao; Peng, Xin; Mao, Chi; Tian, Jia-he; Zhang, Shu-wen; Xu, Fang; Tu, Jing-jing; Liu, Sheng; Hu, Min; Yu, Guang-yan

    2015-01-01

    Bone tissue engineering shows good prospects for mandibular reconstruction. In recent studies, prefabricated tissue-engineered bone (PTEB) by recombinant human bone morphogenetic proteins (rhBMPs) applied in vivo has found to be an effective alternative for autologous bone grafts. However, the optimal time to transfer PTEB for mandibular reconstruction is still not elucidated. Thus, here in an animal experiment of rhesus monkey, the suitable transferring time for PTEB to reconstruct mandibular defects was evaluated by 99mTc-MDP SPECT/CT, and its value in monitoring orthotopic rhBMP-2 implants for mandibular reconstruction was also evaluated. The result of SPECT/CT showed higher 99mTc-MDP uptake, indicating osteoinductivity, in rhBMP-2 incorporated demineralized freeze-dried bone allograft (DFDBA) and coralline hydroxyapatite (CHA) implants than those without BMP stimulation. 99mTc-MDP uptake of rhBMP-2 implant peaked at 8 weeks following implantation while CT showed the density of these implants increased after 13 weeks’ prefabrication. Histology confirmed that mandibular defects were repaired successfully with PTEB or orthotopically rhBMP-2 incorporated CHA implants, in accordance with SPECT/CT findings. Collectively, data shows 99mTc-MDP SPECT/CT is a sensitive and noninvasive tool to monitor osteoinductivity and bone regeneration of PTEB and orthotopic implants. The PTEB achieved peak osteoinductivity and bone density at 8 to 13 weeks following ectopic implantation, which would serve as a recommendable time frame for its transfer to mandibular reconstruction. PMID:26340447

  16. Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering.

    PubMed

    Lienemann, Philipp S; Metzger, Stéphanie; Kiveliö, Anna-Sofia; Blanc, Alain; Papageorgiou, Panagiota; Astolfo, Alberto; Pinzer, Bernd R; Cinelli, Paolo; Weber, Franz E; Schibli, Roger; Béhé, Martin; Ehrbar, Martin

    2015-05-19

    Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (<1 mm). Herein, we employ modular designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials.

  17. Correlation of visceral adipose tissue measured by Lunar Prodigy dual X-ray absorptiometry with MRI and CT in older men.

    PubMed

    Cheung, A S; de Rooy, C; Hoermann, R; Gianatti, E J; Hamilton, E J; Roff, G; Zajac, J D; Grossmann, M

    2016-08-01

    Quantification of abdominal visceral adipose tissue (VAT) is important to understand obesity-related comorbidities. We hypothesized that dual X-ray absorptiometry (DXA) measurements of VAT would correlate with traditional gold standards of magnetic resonance imaging (MRI) and computed tomography (CT) in older men. Deming regression and Bland-Altman plots were used to assess the agreement between VAT measured simultaneously by DXA and MRI (n=95) in a cohort of older males participating in a randomized trial of testosterone replacement for diabetes. We also correlated DXA with single-slice CT (n=102) in a cohort of older males undergoing testosterone deprivation for prostate cancer. Lunar Prodigy DXA scanners using enCORE software was used to measure VAT. DXA VAT volume strongly correlated with MRI VAT volume (r=0.90, P<0.0001) and CT VAT area (r=0.83, P<0.0001). As DXA assesses VAT volume in a smaller compartment than MRI, Bland-Altman analysis demonstrated DXA systematically underestimated VAT by an approximately 30% proportional bias. DXA VAT volume measured by Lunar Prodigy DXA scanners correlate well with gold standard MRI and CT quantification methods, and provides a low radiation, efficient, cost-effective option. Future clinical studies examining the effects of interventions on body composition and regional fat distribution may find DXA an appropriate volumetric method to quantify VAT.

  18. Longitudinal in vivo evaluation of bone regeneration by combined measurement of multi-pinhole SPECT and micro-CT for tissue engineering

    NASA Astrophysics Data System (ADS)

    Lienemann, Philipp S.; Metzger, Stéphanie; Kiveliö, Anna-Sofia; Blanc, Alain; Papageorgiou, Panagiota; Astolfo, Alberto; Pinzer, Bernd R.; Cinelli, Paolo; Weber, Franz E.; Schibli, Roger; Béhé, Martin; Ehrbar, Martin

    2015-05-01

    Over the last decades, great strides were made in the development of novel implants for the treatment of bone defects. The increasing versatility and complexity of these implant designs request for concurrent advances in means to assess in vivo the course of induced bone formation in preclinical models. Since its discovery, micro-computed tomography (micro-CT) has excelled as powerful high-resolution technique for non-invasive assessment of newly formed bone tissue. However, micro-CT fails to provide spatiotemporal information on biological processes ongoing during bone regeneration. Conversely, due to the versatile applicability and cost-effectiveness, single photon emission computed tomography (SPECT) would be an ideal technique for assessing such biological processes with high sensitivity and for nuclear imaging comparably high resolution (<1 mm). Herein, we employ modular designed poly(ethylene glycol)-based hydrogels that release bone morphogenetic protein to guide the healing of critical sized calvarial bone defects. By combined in vivo longitudinal multi-pinhole SPECT and micro-CT evaluations we determine the spatiotemporal course of bone formation and remodeling within this synthetic hydrogel implant. End point evaluations by high resolution micro-CT and histological evaluation confirm the value of this approach to follow and optimize bone-inducing biomaterials.

  19. Pearls and pitfalls in the diagnosis of ureterolithiasis with unenhanced helical CT.

    PubMed

    Dalrymple, N C; Casford, B; Raiken, D P; Elsass, K D; Pagan, R A

    2000-01-01

    Several signs to assist interpretation of unenhanced helical computed tomographic (CT) scans obtained for suspected ureterolithiasis have been described. Because signs such as perinephric stranding are not always readily apparent, a methodical approach to interpretation of CT studies is important in determining the presence or absence of ureterolithiasis. Evaluation of the poles of the kidneys is helpful in detecting subtle stranding of the perinephric fat. Inspection of the intrarenal collecting system within the poles of the kidneys is helpful in identifying subtle collecting system dilatation and can help prevent mistaking an extrarenal pelvis for hydronephrosis. Careful inspection of the ureter throughout its course is the most reliable method of distinguishing between ureteral stones and phleboliths. However, when the ureter cannot be followed antegrade, the pelvic portion can often be identified in a retrograde fashion. When secondary signs of obstruction are present but no stone is present, differential diagnostic considerations include a recently passed stone, pyelonephritis, urinary tract obstruction unrelated to stone disease, and protease inhibitor deposition disease.

  20. Sixty-four-slice CT angiography to determine the three dimensional relationships of vascular and soft tissue wounds in lower extremity war time injuries.

    PubMed

    Smith, Jennifer M; Fox, Charles J; Brazaitis, Michael P; Via, Kathy; Garcia, Roman; Feuerstein, Irwin M

    2010-01-01

    This article analyzes the use and benefits of the 64-slice CT scanner in determining the 3D relationships of vascular and soft tissue wounds in lower extremity war time injuries. A brief overview of CT scanning is given as well as the techniques used to produce the images needed for diagnosis. The series follows two similar cases of war time injury patients at the Walter Reed Army Medical Center. The first case is a 30-year-old active duty male, who presented with multiple trauma from a motor vehicle accident because of an improvised explosive device (IED) blast, sustaining substantial lower extremity injuries. The second case is a 34-year-old active duty male, who presented with multiple trauma blast injuries. Both cases were of interest because the vasculature was found to be very close to the surface of the wound, which put the arteries at risk for rupture and for iatrogenic injury during repeated debridements.

  1. Influence of radiation therapy on the lung-tissue in breast cancer patients: CT-assessed density changes and associated symptoms

    SciTech Connect

    Rotstein, S.; Lax, I.; Svane, G. )

    1990-01-01

    The relative electron density of lung tissue was measured from computer tomography (CT) slices in 33 breast cancer patients treated by various techniques of adjuvant radiotherapy. The measurements were made before radiotherapy, 3 months and 9 months after completion of radiation therapy. The changes in lung densities at 3 months and 9 months were compared to radiation induced radiological (CT) findings. In addition, subjective symptoms such as cough and dyspnoea were assessed before and after radiotherapy. It was observed that the mean of the relative electron density of lung tissue varied from 0.25 when the whole lung was considered to 0.17 when only the anterior lateral quarter of the lung was taken into account. In patients with positive radiological (CT) findings the mean lung density of the anterior lateral quarter increased 2.1 times 3 months after radiotherapy and was still increased 1.6 times 6 months later. For those patients without findings, in the CT pictures the corresponding values were 1.2 and 1.1, respectively. The standard deviation of the pixel values within the anterior lateral quarter of the lung increased 3.8 times and 3.2 times at 3 months and 9 months, respectively, in the former group, as opposed to 1.2 and 1.1 in the latter group. Thirteen patients had an increase in either cough or dyspnoea as observed 3 months after completion of radiotherapy. In eleven patients these symptoms persisted 6 months later. No significant correlation was found between radiological findings and subjective symptoms. However, when three different treatment techniques were compared among 29 patients the highest rate of radiological findings was observed in patients in which the largest lung volumes received the target dose. A tendency towards an increased rate of subjective symptoms was also found in this group.

  2. Consecutive CT-guided core needle tissue biopsy of lung lesions in the same dog at different phases of radiation-induced lung injury

    PubMed Central

    Yin, Zhongyuan; Deng, Sisi; Liang, Zhiwen; Wang, Qiong

    2016-01-01

    This project aimed to set up a Beagle dog model of radiation-induced lung injury in order to supply fresh lung tissue samples in the different injury phases for gene and protein research. Three dogs received 18 Gy X-ray irradiation in one fraction, another three dogs received 8 Gy in each of three fractions at weekly intervals, and one control dog was not irradiated. Acute pneumonitis was observed during the first 3 months after radiation, and chronic lung fibrosis was found during the next 4–12 months in all the dogs exposed to radiation. CT-guided core needle lung lesion biopsies were extracted from each dog five times over the course of 1 year. The dogs remained healthy after each biopsy, and 50–100 mg fresh lung lesion tissues were collected in each operation. The incidence of pneumothorax and hemoptysis was 20% and 2.8%, respectively, in the 35 tissue biopsies. A successful and stable radiation-induced lung injury dog model was established. Lung lesion tissue samples from dogs in acute stage, recovery stage and fibrosis stage were found to be sufficient to support cytology, genomics and proteomics research. This model safely supplied fresh tissue samples that would allow future researchers to more easily explore and develop treatments for radiation-induced lung injury. PMID:27422930

  3. Simulation study on potential accuracy gains from dual energy CT tissue segmentation for low-energy brachytherapy Monte Carlo dose calculations

    NASA Astrophysics Data System (ADS)

    Landry, Guillaume; Granton, Patrick V.; Reniers, Brigitte; Öllers, Michel C.; Beaulieu, Luc; Wildberger, Joachim E.; Verhaegen, Frank

    2011-10-01

    This work compares Monte Carlo (MC) dose calculations for 125I and 103Pd low-dose rate (LDR) brachytherapy sources performed in virtual phantoms containing a series of human soft tissues of interest for brachytherapy. The geometries are segmented (tissue type and density assignment) based on simulated single energy computed tomography (SECT) and dual energy (DECT) images, as well as the all-water TG-43 approach. Accuracy is evaluated by comparison to a reference MC dose calculation performed in the same phantoms, where each voxel's material properties are assigned with exactly known values. The objective is to assess potential dose calculation accuracy gains from DECT. A CT imaging simulation package, ImaSim, is used to generate CT images of calibration and dose calculation phantoms at 80, 120, and 140 kVp. From the high and low energy images electron density ρe and atomic number Z are obtained using a DECT algorithm. Following a correction derived from scans of the calibration phantom, accuracy on Z and ρe of ±1% is obtained for all soft tissues with atomic number Z in [6,8] except lung. GEANT4 MC dose calculations based on DECT segmentation agreed with the reference within ±4% for 103Pd, the most sensitive source to tissue misassignments. SECT segmentation with three tissue bins as well as the TG-43 approach showed inferior accuracy with errors of up to 20%. Using seven tissue bins in our SECT segmentation brought errors within ±10% for 103Pd. In general 125I dose calculations showed higher accuracy than 103Pd. Simulated image noise was found to decrease DECT accuracy by 3-4%. Our findings suggest that DECT-based segmentation yields improved accuracy when compared to SECT segmentation with seven tissue bins in LDR brachytherapy dose calculation for the specific case of our non-anthropomorphic phantom. The validity of our conclusions for clinical geometry as well as the importance of image noise in the tissue segmentation procedure deserves further

  4. Simulation study on potential accuracy gains from dual energy CT tissue segmentation for low-energy brachytherapy Monte Carlo dose calculations.

    PubMed

    Landry, Guillaume; Granton, Patrick V; Reniers, Brigitte; Ollers, Michel C; Beaulieu, Luc; Wildberger, Joachim E; Verhaegen, Frank

    2011-10-07

    This work compares Monte Carlo (MC) dose calculations for (125)I and (103)Pd low-dose rate (LDR) brachytherapy sources performed in virtual phantoms containing a series of human soft tissues of interest for brachytherapy. The geometries are segmented (tissue type and density assignment) based on simulated single energy computed tomography (SECT) and dual energy (DECT) images, as well as the all-water TG-43 approach. Accuracy is evaluated by comparison to a reference MC dose calculation performed in the same phantoms, where each voxel's material properties are assigned with exactly known values. The objective is to assess potential dose calculation accuracy gains from DECT. A CT imaging simulation package, ImaSim, is used to generate CT images of calibration and dose calculation phantoms at 80, 120, and 140 kVp. From the high and low energy images electron density ρ(e) and atomic number Z are obtained using a DECT algorithm. Following a correction derived from scans of the calibration phantom, accuracy on Z and ρ(e) of ±1% is obtained for all soft tissues with atomic number Z ∊ [6,8] except lung. GEANT4 MC dose calculations based on DECT segmentation agreed with the reference within ±4% for (103)Pd, the most sensitive source to tissue misassignments. SECT segmentation with three tissue bins as well as the TG-43 approach showed inferior accuracy with errors of up to 20%. Using seven tissue bins in our SECT segmentation brought errors within ±10% for (103)Pd. In general (125)I dose calculations showed higher accuracy than (103)Pd. Simulated image noise was found to decrease DECT accuracy by 3-4%. Our findings suggest that DECT-based segmentation yields improved accuracy when compared to SECT segmentation with seven tissue bins in LDR brachytherapy dose calculation for the specific case of our non-anthropomorphic phantom. The validity of our conclusions for clinical geometry as well as the importance of image noise in the tissue segmentation procedure deserves

  5. Initial implementation of the conversion from the energy-subtracted CT number to electron density in tissue inhomogeneity corrections: An anthropomorphic phantom study of radiotherapy treatment planning

    SciTech Connect

    Tsukihara, Masayoshi; Noto, Yoshiyuki; Sasamoto, Ryuta; Hayakawa, Takahide; Saito, Masatoshi

    2015-03-15

    Purpose: To achieve accurate tissue inhomogeneity corrections in radiotherapy treatment planning, the authors had previously proposed a novel conversion of the energy-subtracted computed tomography (CT) number to an electron density (ΔHU–ρ{sub e} conversion), which provides a single linear relationship between ΔHU and ρ{sub e} over a wide range of ρ{sub e}. The purpose of this study is to present an initial implementation of the ΔHU–ρ{sub e} conversion method for a treatment planning system (TPS). In this paper, two example radiotherapy plans are used to evaluate the reliability of dose calculations in the ΔHU–ρ{sub e} conversion method. Methods: CT images were acquired using a clinical dual-source CT (DSCT) scanner operated in the dual-energy mode with two tube potential pairs and an additional tin (Sn) filter for the high-kV tube (80–140 kV/Sn and 100–140 kV/Sn). Single-energy CT using the same DSCT scanner was also performed at 120 kV to compare the ΔHU–ρ{sub e} conversion method with a conventional conversion from a CT number to ρ{sub e} (Hounsfield units, HU–ρ{sub e} conversion). Lookup tables for ρ{sub e} calibration were obtained from the CT image acquisitions for tissue substitutes in an electron density phantom (EDP). To investigate the beam-hardening effect on dosimetric uncertainties, two EDPs with different sizes (a body EDP and a head EDP) were used for the ρ{sub e} calibration. Each acquired lookup table was applied to two radiotherapy plans designed using the XiO TPS with the superposition algorithm for an anthropomorphic phantom. The first radiotherapy plan was for an oral cavity tumor and the second was for a lung tumor. Results: In both treatment plans, the performance of the ΔHU–ρ{sub e} conversion was superior to that of the conventional HU–ρ{sub e} conversion in terms of the reliability of dose calculations. Especially, for the oral tumor plan, which dealt with dentition and bony structures, treatment

  6. Modeling mechanical signals on the surface of µCT and CAD based rapid prototype scaffold models to predict (early stage) tissue development.

    PubMed

    Hendrikson, W J; van Blitterswijk, C A; Verdonschot, N; Moroni, L; Rouwkema, J

    2014-09-01

    In the field of tissue engineering, mechano-regulation theories have been applied to help predict tissue development in tissue engineering scaffolds in the past. For this, finite element models (FEMs) were used to predict the distribution of strains within a scaffold. However, the strains reported in these studies are volumetric strains of the material or strains developed in the extracellular matrix occupying the pore space. The initial phase of cell attachment and growth on the biomaterial surface has thus far been neglected. In this study, we present a model that determines the magnitude of biomechanical signals on the biomaterial surface, enabling us to predict cell differentiation stimulus values at this initial stage. Results showed that magnitudes of the 2D strain--termed surface strain--were lower when compared to the 3D volumetric strain or the conventional octahedral shear strain as used in current mechano-regulation theories. Results of both µCT and CAD derived FEMs from the same scaffold were compared. Strain and fluid shear stress distributions, and subsequently the cell differentiation stimulus, were highly dependent on the pore shape. CAD models were not able to capture the distributions seen in the µCT FEM. The calculated mechanical stimuli could be combined with current mechanobiological models resulting in a tool to predict cell differentiation in the initial phase of tissue engineering. Although experimental data is still necessary to properly link mechanical signals to cell behavior in this specific setting, this model is an important step towards optimizing scaffold architecture and/or stimulation regimes.

  7. Registration-based estimates of local lung tissue expansion compared to xenon-CT measures of specific ventilation

    PubMed Central

    Reinhardt, Joseph M.; Ding, Kai; Cao, Kunlin; Christensen, Gary E.; Hoffman, Eric A.; Bodas, Shalmali V.

    2008-01-01

    The main function of the respiratory system is gas exchange. Since many disease or injury conditions can cause biomechanical or material property changes that can alter lung function, there is a great interest in measuring regional lung ventilation and regional specific volume change. We describe a registration-based technique for estimating local lung expansion from multiple respiratory-gated CT images of the thorax. The degree of regional lung expansion is measured using the Jacobian (a function of local partial derivatives) of the registration displacement field, which we show is directly related to specific volume change. We compare the ventral-dorsal patterns of lung expansion estimated across five pressure changes to a xenon CT based measure of specific ventilation in five anesthetized sheep studied in the supine orientation. Using 3D image registration to match images acquired at 10 cm H2O and 15 H2O airway pressures gave the best match between the average Jacobian and the xenon CT specific ventilation (linear regression, average r2 = 0.73). PMID:18501665

  8. Registration-based estimates of local lung tissue expansion compared to xenon CT measures of specific ventilation.

    PubMed

    Reinhardt, Joseph M; Ding, Kai; Cao, Kunlin; Christensen, Gary E; Hoffman, Eric A; Bodas, Shalmali V

    2008-12-01

    The main function of the respiratory system is gas exchange. Since many disease or injury conditions can cause biomechanical or material property changes that can alter lung function, there is a great interest in measuring regional lung ventilation and regional specific volume change. We describe a registration-based technique for estimating local lung expansion from multiple respiratory-gated CT images of the thorax. The degree of regional lung expansion is measured using the Jacobian (a function of local partial derivatives) of the registration displacement field, which we show is directly related to specific volume change. We compare the ventral-dorsal patterns of lung expansion estimated across five pressure changes to a xenon CT based measure of specific ventilation in five anesthetized sheep studied in the supine orientation. Using 3D image registration to match images acquired at 10 cm H(2)O and 15 cm H(2)O airway pressures gave the best match between the average Jacobian and the xenon CT specific ventilation (linear regression, average r(2)=0.73).

  9. Characterization of brown adipose tissue ¹⁸F-FDG uptake in PET/CT imaging and its influencing factors in the Chinese population.

    PubMed

    Shao, Xiaonan; Shao, Xiaoliang; Wang, Xiaosong; Wang, Yuetao

    2016-01-01

    (18)F-FDG PET/CT has been widely applied for tumor imaging. However, it is reported that many normal tissues, e.g., brown adipose tissue, can also uptake (18)F-FDG. The purpose of this study was to determine the imaging characteristics of (18)F-FDG uptake in brown adipose tissue (BAT) in PET/CT. A total of 2,944 patients who underwent PET/CT from September 2011 to March 2013 were analyzed retrospectively. Imaging features of (18)F-FDG uptake in BAT were analyzed. Univariate analysis and logistic regression analysis were performed to evaluate the effect of age, gender, cancer status, body mass index (BMI), average daily maximum temperature of imaging month and fasting plasma glucose (Glu) on the positive rate of (18)F-FDG uptake in BAT. The results showed that 1.9% (57/2944) patients had (18)F-FDG uptake in BAT. (18)F-FDG, manifested as flaky, nodular and beaded shape, was symmetrically distributed in the adipose tissues of cervical and supraclavicular, mediastinal, paravertebral, and perirenal areas. Uptake of (18)F-FDG within cervical/supraclavicular area was most common (89.5%, 51/57) with an SUVmax ranging from 2.8 to 31.4. Univariate analysis showed that gender and cancer status were not significantly correlated with the BAT (18)F-FDG uptake rate. In contrast, age, BMI, Glu and average daily maximum temperature in the imaging month were significantly correlated with the BAT (18)F-FDG uptake rate (P<0.05). Further logistic regression analysis showed that only age, BMI and average daily maximum temperature were significant (OR<1, P<0.05). Based on the value of OR, the most significant factor that affects BAT (18)F-FDG uptake rate was age, followed by the average daily maximum temperature and BMI. We concluded that Chinese adult has low positive rate of (18)F-FDG uptake in BAT. Cervical/Supraclavicular is the most common area with BAT (18)F-FDG uptake. Age, average daily maximum temperature and BMI are independent factors affecting (18)F-FDG uptake.

  10. CT Enterography

    MedlinePlus

    ... obstructions and Crohn’s disease. CT scanning is fast, painless, noninvasive and accurate. CT enterography is better able ... the benefits vs. risks? Benefits CT scanning is painless, noninvasive and accurate. A major advantage of CT ...

  11. 3D strain measurement in soft tissue: demonstration of a novel inverse finite element model algorithm on MicroCT images of a tissue phantom exposed to negative pressure wound therapy.

    PubMed

    Wilkes, R; Zhao, Y; Cunningham, K; Kieswetter, K; Haridas, B

    2009-07-01

    This study describes a novel system for acquiring the 3D strain field in soft tissue at sub-millimeter spatial resolution during negative pressure wound therapy (NPWT). Recent research in advanced wound treatment modalities theorizes that microdeformations induced by the application of sub-atmospheric (negative) pressure through V.A.C. GranuFoam Dressing, a reticulated open-cell polyurethane foam (ROCF), is instrumental in regulating the mechanobiology of granulation tissue formation [Saxena, V., Hwang, C.W., Huang, S., Eichbaum, Q., Ingber, D., Orgill, D.P., 2004. Vacuum-assisted closure: Microdeformations of wounds and cell proliferation. Plast. Reconstr. Surg. 114, 1086-1096]. While the clinical response is unequivocal, measurement of deformations at the wound-dressing interface has not been possible due to the inaccessibility of the wound tissue beneath the sealed dressing. Here we describe the development of a bench-test wound model for microcomputed tomography (microCT) imaging of deformation induced by NPWT and an algorithm set for quantifying the 3D strain field at sub-millimeter resolution. Microdeformations induced in the tissue phantom revealed average tensile strains of 18%-23% at sub-atmospheric pressures of -50 to -200 mmHg (-6.7 to -26.7 kPa). The compressive strains (22%-24%) and shear strains (20%-23%) correlate with 2D FEM studies of microdeformational wound therapy in the reference cited above. We anticipate that strain signals quantified using this system can then be used in future research aimed at correlating the effects of mechanical loading on the phenotypic expression of dermal fibroblasts in acute and chronic ulcer models. Furthermore, the method developed here can be applied to continuum deformation analysis in other contexts, such as 3D cell culture via confocal microscopy, full scale CT and MRI imaging, and in machine vision.

  12. Reproducibility of Facial Soft Tissue Thickness Measurements Using Cone-Beam CT Images According to the Measurement Methods.

    PubMed

    Hwang, Hyeon-Shik; Choe, Seon-Yeong; Hwang, Ji-Sup; Moon, Da-Nal; Hou, Yanan; Lee, Won-Joon; Wilkinson, Caroline

    2015-07-01

    The purpose of this study was to establish the reproducibility of facial soft tissue (ST) thickness measurements by comparing three different measurement methods applied at 32 landmarks on three-dimensional cone-beam computed tomography (CBCT) images. Two observers carried out the measurements of facial ST thickness of 20 adult subjects using CBCT scan data, and inter- and intra-observer reproducibilities were evaluated. The measurement method of "perpendicular to bone" resulted in high inter- and intra-observer reproducibility at all 32 landmarks. In contrast, the "perpendicular to skin" method and "direct" method, which measures a distance between one point on bone and the other point on skin, presented low reproducibility. The results indicate that reproducibility could be increased by identifying the landmarks on hard tissue images, rather than on ST images, and the landmark description used in this study can be used in the establishment of reliable tissue depth data using CBCT images.

  13. Studying Maximum Plantar Stress per Insole Design Using Foot CT-Scan Images of Hyperelastic Soft Tissues

    PubMed Central

    Sarikhani, Ali; Motalebizadeh, Abbas; Kamali Doost Azad, Babak

    2016-01-01

    The insole shape and the resulting plantar stress distribution have a pivotal impact on overall health. In this paper, by Finite Element Method, maximum stress value and stress distribution of plantar were studied for different insoles designs, which are the flat surface and the custom-molded (conformal) surface. Moreover, insole thickness, heel's height, and different materials were used to minimize the maximum stress and achieve the most uniform stress distribution. The foot shape and its details used in this paper were imported from online CT-Scan images. Results show that the custom-molded insole reduced maximum stress 40% more than the flat surface insole. Upon increase of thickness in both insole types, stress distribution becomes more uniform and maximum stress value decreases up to 10%; however, increase of thickness becomes ineffective above a threshold of 1 cm. By increasing heel height (degree of insole), maximum stress moves from heel to toes and becomes more uniform. Therefore, this scenario is very helpful for control of stress in 0.2° to 0.4° degrees for custom-molded insole and over 1° for flat insole. By changing the material of the insole, the value of maximum stress remains nearly constant. The custom-molded (conformal) insole which has 0.5 to 1 cm thickness and 0.2° to 0.4° degrees is found to be the most compatible form for foot. PMID:27843284

  14. Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies

    PubMed Central

    Panzer, Stephanie; Mc Coy, Mark R.; Hitzl, Wolfgang; Piombino-Mascali, Dario; Jankauskas, Rimantas; Zink, Albert R.; Augat, Peter

    2015-01-01

    The purpose of this study was to develop a checklist for standardized assessment of soft tissue preservation in human mummies based on whole-body computed tomography examinations, and to add a scoring system to facilitate quantitative comparison of mummies. Computed tomography examinations of 23 mummies from the Capuchin Catacombs of Palermo, Sicily (17 adults, 6 children; 17 anthropogenically and 6 naturally mummified) and 7 mummies from the crypt of the Dominican Church of the Holy Spirit of Vilnius, Lithuania (5 adults, 2 children; all naturally mummified) were used to develop the checklist following previously published guidelines. The scoring system was developed by assigning equal scores for checkpoints with equivalent quality. The checklist was evaluated by intra- and inter-observer reliability. The finalized checklist was applied to compare the groups of anthropogenically and naturally mummified bodies. The finalized checklist contains 97 checkpoints and was divided into two main categories, “A. Soft Tissues of Head and Musculoskeletal System” and “B. Organs and Organ Systems”, each including various subcategories. The complete checklist had an intra-observer reliability of 98% and an inter-observer reliability of 93%. Statistical comparison revealed significantly higher values in anthropogenically compared to naturally mummified bodies for the total score and for three subcategories. In conclusion, the developed checklist allows for a standardized assessment and documentation of soft tissue preservation in whole-body computed tomography examinations of human mummies. The scoring system facilitates a quantitative comparison of the soft tissue preservation status between single mummies or mummy collections. PMID:26244862

  15. Implications of Pericardial, Visceral and Subcutaneous Adipose Tissue on Vascular Inflammation Measured Using 18FDG-PET/CT

    PubMed Central

    Hong, Ho Cheol; Hwang, Soon Young; Park, Soyeon; Ryu, Ja Young; Choi, Hae Yoon; Yoo, Hye Jin; Seo, Ji-A; Kim, Sin Gon; Kim, Nan Hee; Baik, Sei Hyun; Choi, Dong Seop

    2015-01-01

    Objective Pericardial adipose tissue (PAT) is associated with adverse cardiometabolic risk factors and cardiovascular disease (CVD). However, the relative implications of PAT, abdominal visceral and subcutaneous adipose tissue on vascular inflammation have not been explored. Method and Results We compared the association of PAT, abdominal visceral fat area (VFA), and subcutaneous fat area (SFA) with vascular inflammation, represented as the target-to-background ratio (TBR), the blood-normalized standardized uptake value measured using 18F-Fluorodeoxyglucose Positron Emission Tomography (18FDG-PET) in 93 men and women without diabetes or CVD. Age- and sex-adjusted correlation analysis showed that PAT, VFA, and SFA were positively associated with most cardiometabolic risk factors, including systolic blood pressure, LDL-cholesterol, triglycerides, glucose, insulin resistance and high sensitive C-reactive proteins (hsCRP), whereas they were negatively associated with HDL-cholesterol. In particular, the maximum TBR (maxTBR) values were positively correlated with PAT and VFA (r = 0.48 and r = 0.45, respectively; both P <0.001), whereas SFA showed a relatively weak positive relationship with maxTBR level (r = 0.31, P = 0.003). Conclusion This study demonstrated that both PAT and VFA are significantly and similarly associated with vascular inflammation and various cardiometabolic risk profiles. PMID:26270050

  16. Non-invasive monitoring of BMP-2 retention and bone formation in composites for bone tissue engineering using SPECT/CT and scintillation probes.

    PubMed

    Kempen, Diederik H R; Yaszemski, Michael J; Heijink, Andras; Hefferan, Theresa E; Creemers, Laura B; Britson, Jason; Maran, Avudaiappan; Classic, Kelly L; Dhert, Wouter J A; Lu, Lichun

    2009-03-19

    Non-invasive imaging can provide essential information for the optimization of new drug delivery-based bone regeneration strategies to repair damaged or impaired bone tissue. This study investigates the applicability of nuclear medicine and radiological techniques to monitor growth factor retention profiles and subsequent effects on bone formation. Recombinant human bone morphogenetic protein-2 (BMP-2, 6.5 microg/scaffold) was incorporated into a sustained release vehicle consisting of poly(lactic-co-glycolic acid) microspheres embedded in a poly(propylene fumarate) scaffold surrounded by a gelatin hydrogel and implanted subcutaneously and in 5-mm segmental femoral defects in 9 rats for a period of 56 days. To determine the pharmacokinetic profile, BMP-2 was radiolabeled with (125)I and the local retention of (125)I-BMP-2 was measured by single photon emission computed tomography (SPECT), scintillation probes and ex vivo scintillation analysis. Bone formation was monitored by micro-computed tomography (microCT). The scaffolds released BMP-2 in a sustained fashion over the 56-day implantation period. A good correlation between the SPECT and scintillation probe measurements was found and there were no significant differences between the non-invasive and ex-vivo counting method after 8 weeks of follow up. SPECT analysis of the total body and thyroid counts showed a limited accumulation of (125)I within the body. Ectopic bone formation was induced in the scaffolds and the femur defects healed completely. In vivo microCT imaging detected the first signs of bone formation at days 14 and 28 for the orthotopic and ectopic implants, respectively, and provided a detailed profile of the bone formation rate. Overall, this study clearly demonstrates the benefit of applying non-invasive techniques in drug delivery-based bone regeneration strategies by providing detailed and reliable profiles of the growth factor retention and bone formation at different implantation sites in a

  17. Quantification of the Iodine Content of Perigastric Adipose Tissue by Dual-Energy CT: A Novel Method for Preoperative Diagnosis of T4-Stage Gastric Cancer

    PubMed Central

    Shi, Gaofeng; Li, Yang; Li, Yong

    2015-01-01

    This study investigated the utility of quantifying iodine concentration (IC) in perigastric adipose tissue, using dual-energy computed tomography (DECT), for the detection of T4a-stage gastric cancer. Fifty-four patients with gastric cancer were enrolled at the Fourth Hospital of Hebei Medical University between January and June 2013. Patients were imaged preoperatively with conventional computed tomography (CT) scans and DECT, and the IC in perigastric fat adjacent to the tumor calculated from arterial phase (AP) and portal venous phase (PVP) images. The patients subsequently received surgical treatment (gastrectomy), and histologic analysis of resected specimens was used as a ‘gold standard’ reference for cancer staging. Receiver operating characteristic (ROC) curve analysis was employed to assess the utility of DECT for identifying T4a-stage gastric cancer, with optimal IC thresholds determined from the area under the ROC curve (AUC). Postoperative histology revealed that 32 patients had serosal invasion (group A), and 22 did not (group B). The accuracy of conventional CT for distinguishing stage T4 from non-T4 stages was 68.5% (37/54). IC was significantly higher in group A than in group B (AP: 0.60±0.34 vs. 0.09±0.19 mg/mL, p<0.001; PVP: 0.83±0.41 vs. 0.27±0.21 mg/mL, p<0.001). The sensitivity, specificity and AUC for detecting serosal invasion were 77.1%, 79.2% and 0.89 at an IC threshold of 0.25 mg/mL for AP images; and 80.0%, 79.2% and 0.90 at an IC threshold of 0.45 mg/mL for PVP images. These results indicated that Iodine quantification in perigastric fat using DECT is an accurate method for detecting serosal invasion by gastric cancer. PMID:26372042

  18. Non-invasive monitoring of BMP-2 retention and bone formation in composites for bone tissue engineering using SPECT/CT and scintillation probes

    PubMed Central

    Kempen, Diederik H.R.; Yaszemski, Michael J.; Heijink, Andras; Hefferan, Theresa E.; Creemers, Laura B.; Britson, Jason; Maran, Avudaiappan; Classic, Kelly L.; Dhert, Wouter J.A.; Lu, Lichun

    2014-01-01

    Non-invasive imaging can provide essential information for the optimization of new drug delivery-based bone regeneration strategies to repair damaged or impaired bone tissue. This study investigates the applicability of nuclear medicine and radiological techniques to monitor growth factor retention profiles and subsequent effects on bone formation. Recombinant human bone morphogenetic protein-2 (BMP-2, 6.5 μg/scaffold) was incorporated into a sustained release vehicle consisting of poly(lactic-co-glycolic acid) microspheres embedded in a poly(propylene fumarate) scaffold surrounded by a gelatin hydrogel and implanted subcutaneously and in 5-mm segmental femoral defects in 9 rats for a period of 56 days. To determine the pharmacokinetic profile, BMP-2 was radiolabeled with 125I and the local retention of 125I-BMP-2 was measured by single photon emission computed tomography (SPECT), scintillation probes and ex vivo scintillation analysis. Bone formation was monitored by micro-computed tomography (μCT). The scaffolds released BMP-2 in a sustained fashion over the 56-day implantation period. A good correlation between the SPECT and scintillation probe measurements was found and there were no significant differences between the non-invasive and ex-vivo counting method after 8 weeks of follow up. SPECT analysis of the total body and thyroid counts showed a limited accumulation of 125I within the body. Ectopic bone formation was induced in the scaffolds and the femur defects healed completely. In vivo μCT imaging detected the first signs of bone formation at days 14 and 28 for the orthotopic and ectopic implants, respectively, and provided a detailed profile of the bone formation rate. Overall, this study clearly demonstrates the benefit of applying non-invasive techniques in drug delivery-based bone regeneration strategies by providing detailed and reliable profiles of the growth factor retention and bone formation at different implantation sites in a limited number

  19. Soft-tissue detectability in cone-beam CT: Evaluation by 2AFC tests in relation to physical performance metrics

    SciTech Connect

    Tward, D. J.; Siewerdsen, J. H.; Daly, M. J.; Richard, S.; Moseley, D. J.; Jaffray, D. A.; Paul, N. S.

    2007-11-15

    Soft-tissue detectability in cone-beam computed tomography (CBCT) was evaluated via two-alternative forced-choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three-dimensional (3D) noise-power spectrum (NPS) in axial and sagittal or coronal planes, and the effect of prior knowledge on detectability. Custom-built phantoms ({approx}15 cm diameter cylinders) containing soft-tissue-simulating spheres of variable contrast and diameter were imaged on an experimental CBCT bench. The proportion of correct responses (P{sub corr}) in 2AFC tests was analyzed as a figure of merit, ideally equal to the area under the receiver operating characteristic curve. P{sub corr} was evaluated as a function of the sphere diameter (1.6-12.7 mm), contrast (20-165 HU), dose (1-7 mGy), plane of visualization (axial/sagittal), apodization filter (Hanning and Ram-Lak), and prior knowledge provided to the observer [ranging from stimulus known exactly (SKE) to stimulus unknown (SUK)]. Detectability limits were characterized in terms of the dose required to achieve a given level of P{sub corr} (e.g., 70%). For example, a 20 HU stimulus of diameter down to {approx}6 mm was detected with P{sub corr} 70% at dose {>=}2 mGy. Detectability tended to be greater in axial than in sagittal planes, an effect amplified by sharper apodization filters in a manner consistent with 3D NPS asymmetry. Prior knowledge had a marked influence on detectability - e.g., P{sub corr} for a {approx}6 mm(20 HU) sphere was {approx}55%-65% under SUK conditions, compared to {approx}70%-85% for SKE conditions. Human observer tests suggest practical implications for implementation of CBCT: (i) Detectability limits help to define minimum-dose imaging techniques for specific imaging tasks; (ii) detectability of a given structure can vary between axial and sagittal/coronal planes, owing to the spatial-frequency content of the 3D NPS in relation to the

  20. Soft-tissue detectability in cone-beam CT: evaluation by 2AFC tests in relation to physical performance metrics.

    PubMed

    Tward, D J; Siewerdsen, J H; Daly, M J; Richard, S; Moseley, D J; Jaffray, D A; Paul, N S

    2007-11-01

    Soft-tissue detectability in cone-beam computed tomography (CBCT) was evaluated via two-alternative forced-choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three-dimensional (3D) noise-power spectrum (NPS) in axial and sagittal or coronal planes, and the effect of prior knowledge on detectability. Custom-built phantoms (approximately 15 cm diameter cylinders) containing soft-tissue-simulating spheres of variable contrast and diameter were imaged on an experimental CBCT bench. The proportion of correct responses (Pcorr) in 2AFC tests was analyzed as a figure of merit, ideally equal to the area under the receiver operating characteristic curve. Pcorr was evaluated as a function of the sphere diameter (1.6-12.7 mm), contrast (20-165 HU), dose (1-7 mGy), plane of visualization (axial/sagittal), apodization filter (Hanning and Ram-Lak), and prior knowledge provided to the observer [ranging from stimulus known exactly (SKE) to stimulus unknown (SUK)]. Detectability limits were characterized in terms of the dose required to achieve a given level of Pcorr (e.g., 70%). For example, a 20 HU stimulus of diameter down to approximately 6 mm was detected with Pcorr 70% at dose > or =2 mGy. Detectability tended to be greater in axial than in sagittal planes, an effect amplified by sharper apodization filters in a manner consistent with 3D NPS asymmetry. Prior knowledge had a marked influence on detectability--e.g., Pcorr for a approximately 6 mm (20 HU) sphere was approximately 55%-65% under SUK conditions, compared to approximately 70%-85% for SKE conditions. Human observer tests suggest practical implications for implementation of CBCT: (i) Detectability limits help to define minimum-dose imaging techniques for specific imaging tasks; (ii) detectability of a given structure can vary between axial and sagittal/coronal planes, owing to the spatial-frequency content of the 3D NPS in relation to the

  1. Quantitative assessment of brown adipose tissue metabolic activity and volume using 18F-FDG PET/CT and β3-adrenergic receptor activation

    PubMed Central

    2011-01-01

    Background Brown adipose tissue [BAT] metabolism in vivo is vital for the development of novel strategies in combating obesity and diabetes. Currently, BAT is activated at low temperatures and measured using 2-deoxy-2-18F-fluoro-D-glucose [18F-FDG] positron-emission tomography [PET]. We report the use of β3-adrenergic receptor-mediated activation of BAT at ambient temperatures using (R, R)-5-[2-[2,3-(3-chlorphenyl)-2-hydroxyethyl-amino]propyl]-1,3-benzodioxole-2,2-dicarboxylate, disodium salt [CL316,243] (a selective β3-adrenoceptor agonist) and measured by 18F-FDG PET/computed tomography [CT]. Methods Control and CL316,243-treated (2 mg/kg) male Sprague-Dawley rats were administered with 18F-FDG for PET/CT studies and were compared to animals at cold temperatures. Receptor-blocking experiments were carried out using propranolol (5 mg/kg). Dose effects of CL316,243 were studied by injecting 0.1 to 1 mg/kg 30 min prior to 18F-FDG administration. Imaging results were confirmed by autoradiography, and histology was done to confirm BAT activation. Results CL316,243-activated interscapular BAT [IBAT], cervical, periaortic, and intercostal BATs were clearly visualized by PET. 18F-FDG uptake of IBAT was increased 12-fold by CL316,243 vs. 1.1-fold by cold exposure when compared to controls. 18F-FDG uptake of the CL-activated IBAT was reduced by 96.0% using intraperitoneal administration of propranolol. Average 18F-FDG uptake of IBAT increased 3.6-, 3.5-, and 7.6-fold by doses of 0.1, 0.5, and 1 mg/kg CL, respectively. Ex vivo 18F-FDG autoradiography and histology of transverse sections of IBAT confirmed intense uptake in the CL-activated group and activated IBAT visualized by PET. Conclusion Our study indicated that BAT metabolic activity could be evaluated by 18F-FDG PET using CL316,243 at ambient temperature in the rodent model. This provides a feasible and reliable method to study BAT metabolism. PMID:22214183

  2. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  3. CT of abdominal tuberculosis

    SciTech Connect

    Epstein, B.M.; Mann, J.H.

    1982-11-01

    Intraabdominal tuberculosis (TB) presents with a wide variety of clinical and radiologic features. Besides the reported computed tomographic (CT) finding of high-density ascites in tuberculous peritonitis, this report describes additional CT features highly suggestive of abdominal tuberculosis in eight cases: (1) irregular soft-tissue densities in the omental area; (2) low-density masses surrounded by thick solid rims; (3) a disorganized appearance of soft-tissue densities, fluid, and bowel loops forming a poorly defined mass; (4) low-density lymph nodes with a multilocular appearance after intravenous contrast administration; and (5) possibly high-density ascites. The differential diagnosis of these features include lymphoma, various forms of peritonitis, peritoneal carcinomatosis, and peritoneal mesothelioma. It is important that the CT features of intraabdominal tuberculosis be recognized in order that laparotomy be avoided and less invasive procedures (e.g., laparoscopy, biopsy, or a trial of antituberculous therapy) be instituted.

  4. Chronic osteomyelitis examined by CT

    SciTech Connect

    Wing, V.W.; Jeffrey, R.B. Jr.; Federle, M.P.; Helms, C.A.; Trafton, P.

    1985-01-01

    CT examination of 25 patients who had acute exacerbations of chronic osteomyelitis allowed for the correct identification of single or multiple sequestra in 14 surgical patients. Plain radiographs were equivocal for sequestra in seven of these patients, because the sequestra were too small or because diffuse bony sclerosis was present. CT also demonstrated a foreign body and five soft tissue abscesses not suspected on the basis of plain radiographs. CT studies, which helped guide the operative approach, were also useful in treating those patients whose plain radiographs were positive for sequestra. The authors review the potential role of CT in evaluating patients with chronic osteomyelitis.

  5. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

  6. The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256-slice CT: How can we minimize the risk for deterministic effects?

    SciTech Connect

    Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis; Papadakis, Antonios E.; Damilakis, John

    2013-01-15

    Purpose: To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size/shape, head position during the examination and bowtie filter used on peak tissue doses. Methods: The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peak tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size/shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. Results: The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of

  7. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    SciTech Connect

    Sommer, C. M.; Fritz, S.; Vollherbst, D.; Zelzer, S.; Wachter, M. F. Bellemann, N. Gockner, T. Mokry, T. Schmitz, A.; Aulmann, S.; Stampfl, U.; Pereira, P.; Kauczor, H. U.; Werner, J.; Radeleff, B. A.

    2015-02-15

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm{sup 3}, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm{sup 3}, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

  8. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge.

    PubMed

    Ottosson, Rickard O; Behrens, Claus F

    2011-11-21

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise conversion of CT number to density and proper differentiation between air and lung. Existing tools do not address this issue specifically. Moreover, their density conversion may depend on the number of media used. Differentiation between air and lung is an important task in MC treatment planning and misassignment may lead to local dose errors on the order of 10%. A novel algorithm, CTC-ask, is presented in this study. It enables locally confined constraints for the media assignment and is independent of the number of media used for the conversion of CT number to density. MC compatible phantoms were generated for two clinical cases using a CT-conversion scheme implemented in both CTC-ask and the DICOM-RT toolbox. Full MC dose calculation was subsequently conducted and the resulting dose distributions were compared. The DICOM-RT toolbox inaccurately assigned lung in 9.9% and 12.2% of the voxels located outside of the lungs for the two cases studied, respectively. This was completely avoided by CTC-ask. CTC-ask is able to reduce anatomically irrational media assignment. The CTC-ask source code can be made available upon request to the authors.

  9. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge

    NASA Astrophysics Data System (ADS)

    Ottosson, Rickard O.; Behrens, Claus F.

    2011-11-01

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise conversion of CT number to density and proper differentiation between air and lung. Existing tools do not address this issue specifically. Moreover, their density conversion may depend on the number of media used. Differentiation between air and lung is an important task in MC treatment planning and misassignment may lead to local dose errors on the order of 10%. A novel algorithm, CTC-ask, is presented in this study. It enables locally confined constraints for the media assignment and is independent of the number of media used for the conversion of CT number to density. MC compatible phantoms were generated for two clinical cases using a CT-conversion scheme implemented in both CTC-ask and the DICOM-RT toolbox. Full MC dose calculation was subsequently conducted and the resulting dose distributions were compared. The DICOM-RT toolbox inaccurately assigned lung in 9.9% and 12.2% of the voxels located outside of the lungs for the two cases studied, respectively. This was completely avoided by CTC-ask. CTC-ask is able to reduce anatomically irrational media assignment. The CTC-ask source code can be made available upon request to the authors.

  10. Coupling multiscale X-ray physics and micromechanics for bone tissue composition and elasticity determination from micro-CT data, by example of femora from OVX and sham rats

    NASA Astrophysics Data System (ADS)

    Hasslinger, Patricia; Vass, Viktoria; Dejaco, Alexander; Blanchard, Romane; Örlygsson, Gissur; Gargiulo, Paolo; Hellmich, Christian

    2016-05-01

    Due to its high resolution, micro-CT (Computed Tomograph) scanning is the key to assess bone quality of sham and OVX (ovariectomized) rats. Combination of basic X-ray physics, such as the energy- and chemistry-dependence of attenuation coefficients, with results from ashing tests on rat bones, delivers mineral, organic, and water volume fractions within the voxels. Additional use of a microelastic model for bone provides voxel-specific elastic properties. The new method delivers realistic bone mass densities, and reveals that OVX protocols may indeed induce some bone mass loss, while the average composition of the bone tissue remains largely unaltered.

  11. High-contrast X-ray micro-radiography and micro-CT of ex-vivo soft tissue murine organs utilizing ethanol fixation and large area photon-counting detector

    PubMed Central

    Dudak, Jan; Zemlicka, Jan; Karch, Jakub; Patzelt, Matej; Mrzilkova, Jana; Zach, Petr; Hermanova, Zuzana; Kvacek, Jiri; Krejci, Frantisek

    2016-01-01

    Using dedicated contrast agents high-quality X-ray imaging of soft tissue structures with isotropic micrometre resolution has become feasible. This technique is frequently titled as virtual histology as it allows production of slices of tissue without destroying the sample. The use of contrast agents is, however, often an irreversible time-consuming procedure and despite the non-destructive principle of X-ray imaging, the sample is usually no longer usable for other research methods. In this work we present the application of recently developed large-area photon counting detector for high resolution X-ray micro-radiography and micro-tomography of whole ex-vivo ethanol-preserved mouse organs. The photon counting detectors provide dark-current-free quantum-counting operation enabling acquisition of data with virtually unlimited contrast-to-noise ratio (CNR). Thanks to the very high CNR even ethanol-only preserved soft-tissue samples without addition of any contrast agent can be visualized in great detail. As ethanol preservation is one of the standard steps of tissue fixation for histology, the presented method can open a way for widespread use of micro-CT with all its advantages for routine 3D non-destructive soft-tissue visualisation. PMID:27461900

  12. Semi-Quantitative Calculations of Primary Tumor Metabolic Activity Using F-18 FDG PET/CT as a Predictor of Survival in 92 Patients With High-Grade Bone or Soft Tissue Sarcoma.

    PubMed

    Andersen, Kim Francis; Fuglo, Hanna Maria; Rasmussen, Sine Hvid; Petersen, Michael Mork; Loft, Annika

    2015-07-01

    To assess the prognostic value of primary tumor metabolic activity in patients with high-grade bone sarcomas (BS) or soft tissue sarcomas (STS) using F-18 FDG PET/CT. A single-site, retrospective study including 92 patients with high-grade BS or STS. Pretreatment F-18 FDG PET/CT scan was performed. Clinical data were registered. Accuracy of maximum standardized uptake value of primary tumor (SUVmax) and tumor-to-background (T/B) uptake ratio as prognostic variables and identification of cut-off values to group patients were determined. Kaplan-Meier survival estimates and log-rank test were used to compare survival distributions. Prognostic variables were assessed using Cox proportional hazards regression analysis. Forty-one of 92 patients died during follow-up (45%). Average survival was 6.5 years (95% CI 5.8-7.3 years) and probability of 5-year survival was 52%. Accuracy of SUVmax and T/B uptake ratio as prognostic variables in all patients and during subgroup analysis of patients with STS was significant. No significant results for AUCs were registered in patients with BS. Surgery was independently prognostic for survival throughout multivariate regression analysis of all patients (P = 0.001, HR 3.84) and subgroup analysis (BS: P = 0.02, HR 11.62; STS: P = 0.005, HR 4.13). SUVmax was significant as prognostic variable in all patients (P = 0.02, HR 3.66) and in patients with STS (P = 0.007, HR 3.75). No significant results were demonstrated for T/B uptake ratio. Estimation of primary tumor metabolic activity with pretherapeutic SUVmax using F-18 FDG PET/CT demonstrates independent properties beyond histologic grading for prediction of survival in patients with high-grade STS, but not with high-grade BS.

  13. TU-A-12A-04: Quantitative Texture Features Calculated in Lung Tissue From CT Scans Demonstrate Consistency Between Two Databases From Different Institutions

    SciTech Connect

    Cunliffe, A; Armato, S; Castillo, R; Pham, N; Guerrero, T; Al-Hallaq, H

    2014-06-15

    Purpose: To evaluate the consistency of computed tomography (CT) scan texture features, previously identified as stable in a healthy patient cohort, in esophageal cancer patient CT scans. Methods: 116 patients receiving radiation therapy (median dose: 50.4Gy) for esophageal cancer were retrospectively identified. For each patient, diagnostic-quality pre-therapy (0-183 days) and post-therapy (5-120 days) scans (mean voxel size: 0.8mm×0.8mm×2.5mm) and a treatment planning scan and associated dose map were collected. An average of 501 32x32-pixel ROIs were placed randomly in the lungs of each pre-therapy scan. ROI centers were mapped to corresponding locations in post-therapy and planning scans using the displacement vector field output by demons deformable registration. Only ROIs with mean dose <5Gy were analyzed, as these were expected to contain minimal post-treatment damage. 140 texture features were calculated in pre-therapy and post-therapy scan ROIs and compared using Bland-Altman analysis. For each feature, the mean feature value change and the distance spanned by the 95% limits of agreement were normalized to the mean feature value, yielding normalized range of agreement (nRoA) and normalized bias (nBias). Using Wilcoxon signed rank tests, nRoA and nBias were compared with values computed previously in 27 healthy patient scans (mean voxel size: 0.67mm×0.67mm×1mm) acquired at a different institution. Results: nRoA was significantly (p<0.001) larger in cancer patients than healthy patients. Differences in nBias were not significant (p=0.23). The 20 features identified previously as having nRoA<20% for healthy patients had the lowest nRoA values in the current database, with an average increase of 5.6%. Conclusion: Despite differences in CT scanner type, scan resolution, and patient health status, the same 20 features remained stable (i.e., low variability and bias) in the absence of disease changes for databases from two institutions. Identification of

  14. PET/CT in radiation oncology

    SciTech Connect

    Pan, Tinsu; Mawlawi, Osama

    2008-11-15

    PET/CT is an effective tool for the diagnosis, staging and restaging of cancer patients. It combines the complementary information of functional PET images and anatomical CT images in one imaging session. Conventional stand-alone PET has been replaced by PET/CT for improved patient comfort, patient throughput, and most importantly the proven clinical outcome of PET/CT over that of PET and that of separate PET and CT. There are over two thousand PET/CT scanners installed worldwide since 2001. Oncology is the main application for PET/CT. Fluorine-18 deoxyglucose is the choice of radiopharmaceutical in PET for imaging the glucose uptake in tissues, correlated with an increased rate of glycolysis in many tumor cells. New molecular targeted agents are being developed to improve the accuracy of targeting different disease states and assessing therapeutic response. Over 50% of cancer patients receive radiation therapy (RT) in the course of their disease treatment. Clinical data have demonstrated that the information provided by PET/CT often changes patient management of the patient and/or modifies the RT plan from conventional CT simulation. The application of PET/CT in RT is growing and will become increasingly important. Continuing improvement of PET/CT instrumentation will also make it easier for radiation oncologists to integrate PET/CT in RT. The purpose of this article is to provide a review of the current PET/CT technology, to project the future development of PET and CT for PET/CT, and to discuss some issues in adopting PET/CT in RT and potential improvements in PET/CT simulation of the thorax in radiation therapy.

  15. A comparison of 3D poly(ε-caprolactone) tissue engineering scaffolds produced with conventional and additive manufacturing techniques by means of quantitative analysis of SR μ-CT images

    NASA Astrophysics Data System (ADS)

    Brun, F.; Intranuovo, F.; Mohammadi, S.; Domingos, M.; Favia, P.; Tromba, G.

    2013-07-01

    The technique used to produce a 3D tissue engineering (TE) scaffold is of fundamental importance in order to guarantee its proper morphological characteristics. An accurate assessment of the resulting structural properties is therefore crucial in order to evaluate the effectiveness of the produced scaffold. Synchrotron radiation (SR) computed microtomography (μ-CT) combined with further image analysis seems to be one of the most effective techniques to this aim. However, a quantitative assessment of the morphological parameters directly from the reconstructed images is a non trivial task. This study considers two different poly(ε-caprolactone) (PCL) scaffolds fabricated with a conventional technique (Solvent Casting Particulate Leaching, SCPL) and an additive manufacturing (AM) technique (BioCell Printing), respectively. With the first technique it is possible to produce scaffolds with random, non-regular, rounded pore geometry. The AM technique instead is able to produce scaffolds with square-shaped interconnected pores of regular dimension. Therefore, the final morphology of the AM scaffolds can be predicted and the resulting model can be used for the validation of the applied imaging and image analysis protocols. It is here reported a SR μ-CT image analysis approach that is able to effectively and accurately reveal the differences in the pore- and throat-size distributions as well as connectivity of both AM and SCPL scaffolds.

  16. Canalicular network morphology is the major determinant of the spatial distribution of mass density in human bone tissue: evidence by means of synchrotron radiation phase-contrast nano-CT.

    PubMed

    Hesse, Bernhard; Varga, Peter; Langer, Max; Pacureanu, Alexandra; Schrof, Susanne; Männicke, Nils; Suhonen, Heikki; Maurer, Peter; Cloetens, Peter; Peyrin, Francoise; Raum, Kay

    2015-02-01

    In bone remodeling, maturation of the newly formed osteonal tissue is associated with a rapid primary increase followed by a slower secondary increase of mineralization. This requires supply and precipitation of mineral into the bone matrix. Mineral delivery can occur only from the extracellular fluid via interfaces such as the Haversian system and the osteocyte pore network. We hypothesized that in mineralization, mineral exchange is achieved by the diffusion of mineral from the lacunar-canalicular network (LCN) to the bone matrix, resulting in a gradual change in tissue mineralization with respect to the distance from the pore-matrix interface. We expected to observe alterations in the mass density distribution with tissue age. We further hypothesized that mineral exchange occurs not only at the lacunar but also at the canalicular boundaries. The aim of this study was, therefore, to investigate the spatial distribution of mass density in the perilacunar and pericanalicular bone matrix and to explore how these densities are influenced by tissue aging. This is achieved by analyzing human jawbone specimens originating from four healthy donors and four treated with high-dosage bisphosphonate using synchrotron radiation phase-contrast nano-CT with a 50-nm voxel size. Our results provide the first experimental evidence that mass density in the direct vicinity of both lacunae (p < 0.001) and canaliculi (p < 0.001) is different from the mean matrix mass density, resulting in gradients with respect to the distance from both pore-matrix interfaces, which diminish with increasing tissue age. Though limited by the sample size, these findings support our hypotheses. Moreover, the density gradients are more pronounced around the lacunae than around the canaliculi, which are explained by geometrical considerations in the LCN morphology. In addition, we speculate that mineral exchange occurs at all interfaces of the LCN, not only in mineralization but also in mineral

  17. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... Z CT Colonography Computed tomography (CT) colonography or virtual colonoscopy uses special x-ray equipment to examine ... and blood vessels. CT colonography, also known as virtual colonoscopy, uses low dose radiation CT scanning to ...

  18. Application of SPECT/CT imaging system and radiochemical analysis for investigation of blood kinetics and tissue distribution of radiolabeled plumbagin in healthy and Plasmodium berghei-infected mice.

    PubMed

    Sumsakul, W; Karbwang, J; Na-Bangchang, K

    2016-02-01

    Plumbagin is a derivative of napthoquinone which is isolated from the roots of plants in several families. These compound exhibits a wide range of biological and pharmacological activities including antimalarial, antibacterial, antifungal, and anticancer activities. The aim of the study was to investigate blood kinetics and tissue distribution of plumbagin in healthy and Plasmodium berghei-infected mice using Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) and radiochemical analysis by gamma counter. Plumbagin was labeled with (99m)technetium and the reducing agent stannous chloride dihydrate (50 μg/ml) at pH 6.5. Blood kinetics and tissue distribution of the radiolabeled plumbagin were investigated in healthy and P. berghei-infected mice (2 males and 2 females for each experimental group). In vitro and in vivo stability of plumbagin complex suggested satisfactory stability profiles of (99m)Tc-plumbagin complex in plasma and normal saline (92.21-95.47%) within 24 h. Significant difference in blood kinetics parameters (Cmax, AUC, t1/2, MRT, Vd, and CL) were observed between P. berghei-infected and healthy mice. The labeled complex distributed to all organs of both healthy and infected mice but with high intensity in liver, followed by lung, stomach, large intestine and kidney. Accumulation in spleen was markedly noticeable in the infected mice. Plumbagin-labeled complex was rapidly cleared from blood and major routes of excretion were hepatobiliary and pulmonary routes. In P. berghei-infected mice, t1/2 was significantly decreased, while Vd and CL were increased compared with healthy mice. Result suggests that malaria disease state influenced the pharmacokinetics and disposition of plumbagin. SPECT/CT imaging with radiolabeled (99m)Tc is a viable non-invasive technique that can be applied for investigation of kinetics and biodistribution of plumbagin in animal models.

  19. Multimodal CT in stroke imaging: new concepts.

    PubMed

    Ledezma, Carlos J; Wintermark, Max

    2009-01-01

    A multimodal CT protocol provides a comprehensive noninvasive survey of acute stroke patients with accurate demonstration of the site of arterial occlusion and its hemodynamic tissue status. It combines widespread availability with the ability to provide functional characterization of cerebral ischemia, and could potentially allow more accurate selection of candidates for acute stroke reperfusion therapy. This article discusses the individual components of multimodal CT and addresses the potential role of a combined multimodal CT stroke protocol in acute stroke therapy.

  20. Achieving high-resolution soft-tissue imaging with cone-beam CT: a two-pronged approach for modulation of x-ray fluence and detector gain

    NASA Astrophysics Data System (ADS)

    Graham, S. A.; Siewerdsen, J. H.; Moseley, D. J.; Keller, H.; Shkumat, N. A.; Jaffray, D. A.

    2005-04-01

    Cone-beam computed tomography (CBCT) presents a highly promising and challenging advanced application of flat-panel detectors (FPDs). The great advantage of this adaptable technology is in the potential for sub-mm 3D spatial resolution in combination with soft-tissue detectability. While the former is achieved naturally by CBCT systems incorporating modern FPD designs (e.g., 200 - 400 um pixel pitch), the latter presents a significant challenge due to limitations in FPD dynamic range, large field of view, and elevated levels of x-ray scatter in typical CBCT configurations. We are investigating a two-pronged strategy to maximizing soft-tissue detectability in CBCT: 1) front-end solutions, including novel beam modulation designs (viz., spatially varying compensators) that alleviate detector dynamic range requirements, reduce x-ray scatter, and better distribute imaging dose in a manner suited to soft-tissue visualization throughout the field of view; and 2) back-end solutions, including implementation of an advanced FPD design (Varian PaxScan 4030CB) that features dual-gain and dynamic gain switching that effectively extends detector dynamic range to 18 bits. These strategies are explored quantitatively on CBCT imaging platforms developed in our laboratory, including a dedicated CBCT bench and a mobile isocentric C-arm (Siemens PowerMobil). Pre-clinical evaluation of improved soft-tissue visibility was carried out in phantom and patient imaging with the C-arm device. Incorporation of these strategies begin to reveal the full potential of CBCT for soft-tissue visualization, an essential step in realizing broad utility of this adaptable technology for diagnostic and image-guided procedures.

  1. Helical CT in emergency radiology.

    PubMed

    Novelline, R A; Rhea, J T; Rao, P M; Stuk, J L

    1999-11-01

    Today, a wide range of traumatic and nontraumatic emergency conditions are quickly and accurately diagnosed with helical computed tomography (CT). Many traditional emergency imaging procedures have been replaced with newer helical CT techniques that can be performed in less time and with greater accuracy, less patient discomfort, and decreased cost. The speed of helical technology permits CT examination of seriously ill patients in the emergency department, as well as patients who might not have been taken to CT previously because of the length of the examinations of the past. Also, helical technology permits multiple, sequential CT scans to be quickly obtained in the same patient, a great advance for the multiple-trauma patient. Higher quality CT examinations result from decreased respiratory misregistration, enhanced intravenous contrast material opacification of vascular structures and parenchymal organs, greater flexibility in image reconstruction, and improved multiplanar and three-dimensional reformations. This report summarizes the role and recommended protocols for the helical CT diagnosis of thoracic aortic trauma; aortic dissection; pulmonary embolism; acute conditions of the neck soft tissues; abdominal trauma; urinary tract stones; appendicitis; diverticulitis; abdominal aortic aneurysm; fractures of the face, spine, and extremities; and acute stroke.

  2. Contrast-Enhanced Abdominal Angiographic CT for Intra-abdominal Tumor Embolization: A New Tool for Vessel and Soft Tissue Visualization

    SciTech Connect

    Meyer, Bernhard Christian Frericks, Bernd Benedikt; Albrecht, Thomas; Wolf, Karl-Juergen; Wacker, Frank Klaus

    2007-07-15

    C-Arm cone-beam computed tomography (CACT), is a relatively new technique that uses data acquired with a flat-panel detector C-arm angiography system during an interventional procedure to reconstruct CT-like images. The purpose of this Technical Note is to present the technique, feasibility, and added value of CACT in five patients who underwent abdominal transarterial chemoembolization procedures. Target organs for the chemoembolizations were kidney, liver, and pancreas and a liposarcoma infiltrating the duodenum. The time for patient positioning, C-arm and system preparation, CACT raw data acquisition, and data reconstruction for a single CACT study ranged from 6 to 12 min. The volume data set produced by the workstation was interactively reformatted using maximum intensity projections and multiplanar reconstructions. As part of an angiography system CACT provided essential information on vascular anatomy, therapy endpoints, and immediate follow-up during and immediately after the abdominal interventions without patient transfer. The quality of CACT images was sufficient to influence the course of treatment. This technology has the potential to expedite any interventional procedure that requires three-dimensional information and navigation.

  3. Targeted SPECT/CT Imaging of Matrix Metalloproteinase Activity in the Evaluation of Remodeling Tissue-Engineered Vascular Grafts Implanted in a Growing Lamb Model

    PubMed Central

    Stacy, Mitchel R.; Naito, Yuji; Maxfield, Mark W.; Kurobe, Hirotsugu; Tara, Shuhei; Chan, Chung; Rocco, Kevin A.; Shinoka, Toshiharu; Sinusas, Albert J.; Breuer, Christopher K.

    2014-01-01

    Objective(s) The clinical translation of tissue-engineered vascular grafts has been demonstrated in children. The remodeling of biodegradable, cell-seeded scaffolds to functional neovessels is partially attributed to matrix metalloproteinases. Noninvasive assessment of matrix metalloproteinase activity may indicate graft remodeling and elucidate the progression of neovessel formation. Therefore, matrix metalloproteinase activity was evaluated in grafts implanted in lambs using in vivo and ex vivo hybrid imaging. Graft growth and remodeling was quantified using in vivo X-ray computed tomography angiography. Methods Cell-seeded and unseeded scaffolds were implanted in lambs (n=5) as inferior vena cava interposition grafts. At 2 and 6 months post-implantation, in vivo angiography assessed graft morphology. In vivo and ex vivo single photon emission tomography/X-ray computed tomography imaging was performed with a radiolabeled compound targeting matrix metalloproteinase activity at 6 months. Neotissue was examined at 6 months using qualitative histologic and immunohistochemical staining and quantitative biochemical analysis. Results Seeded grafts demonstrated significant luminal and longitudinal growth from 2 to 6 months. In vivo imaging revealed subjectively higher matrix metalloproteinase activity in grafts vs. native tissue. Ex vivo imaging confirmed a quantitative increase in matrix metalloproteinase activity and demonstrated higher activity in unseeded vs. seeded grafts. Glycosaminoglycan content was increased in seeded grafts vs. unseeded grafts, without significant differences in collagen content. Conclusions Matrix metalloproteinase activity remains elevated in tissue-engineered grafts 6 months post-implantation and may indicate remodeling. Optimization of in vivo imaging to noninvasively evaluate matrix metalloproteinase activity may assist in serial assessment of vascular graft remodeling. PMID:24952823

  4. Askin tumor: CT and FDG-PET/CT imaging findings and follow-up.

    PubMed

    Xia, Tingting; Guan, Yubao; Chen, Yongxin; Li, Jingxu

    2014-07-01

    The aim of the study was to describe the imaging findings of Askin tumors on computed tomography (CT) and fluorine 18 fluorodeoxyglucose-positron emission tomography (FDG-PET/CT).Seventeen cases of Askin tumors confirmed by histopathology were retrospectively analyzed in terms of CT (17 cases) and FDG-PET/CT data (6 cases).Fifteen of the tumors were located in the chest wall and the other 2 were in the anterior middle mediastinum. Of the 15 chest wall cases, 13 demonstrated irregular, heterogeneous soft tissue masses with cystic degeneration and necrosis, and 2 demonstrated homogeneous soft tissue masses on unenhanced CT scans. Two mediastinal tumors demonstrated the irregular, heterogeneous soft tissue masses. Calcifications were found in 2 tumors. The tumors demonstrated heterogeneously enhancement in 16 cases and homogeneous enhancement in 1 case on contrast-enhanced scans. FDG-PET/CT images revealed increased metabolic activity in all 6 cases undergone FDG-PET/CT scan, and the lesion SUVmax ranged from 4.0 to 18.6. At initial diagnosis, CT and FDG-PET/CT scans revealed rib destruction in 9 cases, pleural effusion in 9 cases, and lung metastasis in 1 case. At follow-up, 12 cases showed recurrence and/or metastases, 4 cases showed improvement or remained stable, and 1 was lost to follow-up.In summary, CT and FDG-PET/CT images of Askin tumors showed heterogeneous soft tissue masses in the chest wall and the mediastinum, accompanied by rib destruction, pleural effusion, and increased FDG uptake. CT and FDG-PET/CT imaging play important roles in the diagnosis and follow-up of patients with Askin tumors.

  5. Volume-Based F-18 FDG PET/CT Imaging Markers Provide Supplemental Prognostic Information to Histologic Grading in Patients With High-Grade Bone or Soft Tissue Sarcoma.

    PubMed

    Andersen, Kim Francis; Fuglo, Hanna Maria; Rasmussen, Sine Hvid; Petersen, Michael Mork; Loft, Annika

    2015-12-01

    The aim of the study is to assess the prognostic value of different volume-based calculations of tumor metabolic activity in the initial assessment of patients with high-grade bone sarcomas (BS) and soft tissue sarcomas (STS) using F-18 FDG PET/CT.A single-site, retrospective study from 2002 to 2012 including 92 patients with histologically verified high-grade BS (N = 37) or STS (N = 55). All patients underwent a pretreatment F-18 FDG PET/CT scan. Clinical data were registered. Measurements of the accuracy of metabolic tumor volume with a preset threshold of 40% of the maximum standardized uptake value of primary tumor (MTV40%) and total lesion glycolysis (TLG) as prognostic variables and identification of optimal discriminating cut-off values were performed through ROC curve analysis. Patients were grouped according to the cut-off values. All deaths were considered an event in survival analysis. Kaplan-Meier survival estimates and log-rank test were used to compare the degree of equality of survival distributions. Prognostic variables with related hazard ratios (HR) were assessed using Cox proportional hazards regression analysis.Forty-one of 92 patients died during follow-up (45%; 12 BS and 29 STS). Average survival for included patients was 6.5 years (95% CI 5.8-7.3 years) and probability of 5-year survival was 52%. There was a high-significant accuracy of TLG and MTV40% as prognostic variables when looking on all patients and during subgroup analysis. AUCs were higher for TLG than for MTV40%. TLG above optimal cut-off value was the only variable which was independently prognostic for survival throughout multivariate regression analysis of all included patients (P = 0.01, HR 4.78 [95% CI 1.45-15.87]) and subgroup analysis (BS: P = 0.04, HR 11.11 [95% CI 1.09-111.11]; STS: P < 0.05, HR 3.37 [95% CI 1.02-11.11]). No significant results were demonstrated for MTV40%.Volume-based F-18 FDG PET/CT imaging markers in terms of pretreatment estimation

  6. The numerical stability of transformation-based CT ventilation.

    PubMed

    Castillo, Edward; Castillo, Richard; Vinogradskiy, Yevgeniy; Guerrero, Thomas

    2017-04-01

    Computed tomography (CT)-derived ventilation imaging utilizes deformable image registration (DIR) to recover respiratory-induced tissue volume changes from inhale/exhale 4DCT phases. While current strategies for validating CT ventilation rely on analyzing its correlation with existing functional imaging modalities, the numerical stability of the CT ventilation calculation has not been characterized.

  7. CT & CBCT imaging: assessment of the orbits.

    PubMed

    Hatcher, David C

    2012-11-01

    The orbits can be visualized easily on routine or customized protocols for computed tomography (CT) or cone beam CT (CBCT) scans. Detailed orbital investigations are best performed with 3-dimensional imaging methods. CT scans are preferred for visualizing the osseous orbital anatomy and fissures while magnetic resonance imaging is preferred for evaluating tumors and inflammation. CBCT provides high-resolution anatomic data of the sinonasal spaces, airway, soft tissue surfaces, and bones but does not provide much detail within the soft tissues. This article discusses CBCT imaging of the orbits, osseous anatomy of the orbits, and CBCT investigation of selected orbital pathosis.

  8. Primary epiploic appendagitis: CT diagnosis.

    PubMed

    Sandrasegaran, Kumaresan; Maglinte, Dean D; Rajesh, Arumugam; Akisik, Fatih M

    2004-08-01

    The purpose of this study was to analyze the CT signs of primary epiploic appendagitis. A retrospective search of the CT database over 12 months for this diagnosis revealed 11 cases. The clinical findings were recorded. Softcopy CT images were reviewed by two experienced abdominal radiologists (KS, DM) for location of lesion, size, shape, presence of central hyperdense focus, degree of bowel wall thickening, mass effect, and ancillary signs. Abdominal pain was the primary symptom in all patients. Preliminary diagnoses were appendicitis (n=2), diverticulitis (n=5), pancreatitis (n=1), ovarian lesion (n=1), or unknown (n=2). Abdominal examination and white blood cell count were uninformative. CT examination revealed a solitary (n=11), ovoid (n=9) fatty lesion with some soft tissue stranding adjacent to the left colon (n=6), transverse colon (n=3), or right colon (n=2). Central hyperdensity (n=5), mild bowel wall thickening (n=2), and parietal peritoneal thickening (n=4) were also seen. In 4 patients the lesions were not visible on follow-up CT examination performed 23-184 days later. Primary epiploic appendagitis can clinically mimic other, more serious inflammatory conditions. Knowledge of its findings on CT would help the radiologist make the diagnosis and allow a more conservative approach to patient care.

  9. Granulocytic sarcoma (chloroma): CT manifestations

    SciTech Connect

    Pomeranz, S.J.; Hawkins, H.H.; Towbin, R.; Lisberg, W.N.; Clark, R.A.

    1985-04-01

    Nests of granulocytic tumor cells in patients who have myelogeneous leukemia are termed chloromas. Eight cases of chloroma seen on CT were reviewed. Lymph nodes, subcutaneous tissues, peritoneum, pleural space, pelvis, and portal hepatis were involved. The extracranial appearance of chloroma on CT is that of small, nonenhancing, nodular densities that resemble lymphoma. Cranial involvement is characteristically in the orbit. The central nervous system appearance is variable, however, and high attenuation masses may occur that mimic lymphoma, hematoma, and metastatic neuroblastoma. The recognition of these lesions is important, since radiation, not chemotherapy, is often the preferred treatment for localized chloroma.

  10. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  11. Computed Tomography (CT) - Spine

    MedlinePlus

    ... test used to help diagnose—or rule out—spinal column damage in injured patients. CT scanning is fast, ... CT is to detect—or to rule out—spinal column damage in patients who have been injured. CT ...

  12. Malignant external otitis: CT evaluation

    SciTech Connect

    Curtin, H.D.; Wolfe, P.; May, M.

    1982-11-01

    Malignant external otitis is an aggressive infection caused by Pseudomonas aeruginosa that most often occurs in elderly diabetics. Malignant external otitis often spreads inferiorly from the external canal to involve the subtemporal area and progresses medially towards the petrous apex leading to multiple cranial nerve palsies. The computed tomographic (CT) findings in malignant external otitis include obliteration of the normal fat planes in the subtemporal area as well as patchy destruction of the bony cortex of the mastoid. The point of exit of the various cranial nerves can be identified on CT scans, and the extent of the inflammatory mass correlates well with the clinical findings. Four cases of malignant external otitis are presented. In each case CT provided a good demonstration of involvement of the soft tissues at the base of the skull.

  13. Combined SPECT/CT and PET/CT for breast imaging

    NASA Astrophysics Data System (ADS)

    Russo, Paolo; Larobina, Michele; Di Lillo, Francesca; Del Vecchio, Silvana; Mettivier, Giovanni

    2016-02-01

    In the field of nuclear medicine imaging, breast imaging for cancer diagnosis is still mainly based on 2D imaging techniques. Three-dimensional tomographic imaging with whole-body PET or SPECT scanners, when used for imaging the breast, has performance limits in terms of spatial resolution and sensitivity, which can be overcome only with a dedicated instrumentation. However, only few hybrid imaging systems for PET/CT or SPECT/CT dedicated to the breast have been developed in the last decade, providing complementary functional and anatomical information on normal breast tissue and lesions. These systems are still under development and clinical trials on just few patients have been reported; no commercial dedicated breast PET/CT or SPECT/CT is available. This paper reviews combined dedicated breast PET/CT and SPECT/CT scanners described in the recent literature, with focus on their technological aspects.

  14. Small-animal CT: Its difference from, and impact on, clinical CT

    NASA Astrophysics Data System (ADS)

    Ritman, Erik L.

    2007-10-01

    For whole-body computed tomography (CT) images of small rodents, a voxel resolution of at least 10 -3 mm 3 is needed for scale-equivalence to that currently achieved in clinical CT scanners (˜1 mm 3) in adult humans. These "mini-CT" images generally require minutes rather than seconds to complete a scan. The radiation exposure resulting from these mini-CT scans, while higher than clinical CT scans, is below the level resulting in acute tissue damage. Hence, these scans are useful for performing clinical-type diagnostic and monitoring scans for animal models of disease and their response to treatment. "Micro-CT", with voxel size <10 -5 mm 3, has been useful for imaging isolated, intact organs at an almost cellular level of resolution. Micro-CT has the great advantage over traditional microscopic methods in that it generates detailed three-dimensional images in relatively large, opaque volumes such as an intact rodent heart or kidney. The radiation exposure needed in these scans results in acute tissue damage if used in living animals. Experience with micro-CT is contributing to exploration of new applications for clinical CT imaging by providing insights into different modes of X-ray image formation as follows: Spatial resolution should be sufficient to detect an individual Basic Functional Unit (BFU, the smallest collection of diverse cells, such as hepatic lobule, that behaves like the organ), which requires voxels ˜10 -3 mm 3 in volume, so that the BFUs can be counted. Contrast resolution sufficient to allow quantitation of: New microvascular growth, which manifests as increased tissue contrast due to X-ray contrast agent in those vessels' lumens during passage of injected contrast agent in blood. Impaired endothelial integrity which manifests as increased opacification and delayed washout of contrast from tissues. Discrimination of pathological accumulations of metals such as Fe and Ca, which occur in the arterial wall following hemorrhage or tissue damage

  15. Progress in Fully Automated Abdominal CT Interpretation

    PubMed Central

    Summers, Ronald M.

    2016-01-01

    OBJECTIVE Automated analysis of abdominal CT has advanced markedly over just the last few years. Fully automated assessment of organs, lymph nodes, adipose tissue, muscle, bowel, spine, and tumors are some examples where tremendous progress has been made. Computer-aided detection of lesions has also improved dramatically. CONCLUSION This article reviews the progress and provides insights into what is in store in the near future for automated analysis for abdominal CT, ultimately leading to fully automated interpretation. PMID:27101207

  16. Pulmonary talcosis: CT findings in three cases.

    PubMed

    Padley, S P; Adler, B D; Staples, C A; Miller, R R; Müller, N L

    1993-01-01

    The authors describe the computed tomographic (CT) appearances in three patients with pulmonary talcosis resulting from chronic intravenous drug abuse. There was widespread ground-glass attenuation in one case and an appearance similar to that of progressive massive fibrosis in two cases. In the latter cases, there were confluent perihilar masses with areas of high attenuation. While the CT appearances may be suggestive of pulmonary talcosis, tissue sampling is required for definitive diagnosis.

  17. Ion Stopping Powers and CT Numbers

    SciTech Connect

    Moyers, Michael F.; Sardesai, Milind; Sun, Sean; Miller, Daniel W.

    2010-10-01

    One of the advantages of ion beam therapy is the steep dose gradient produced near the ion's range. Use of this advantage makes knowledge of the stopping powers for all materials through which the beam passes critical. Most treatment planning systems calculate dose distributions using depth dose data measured in water and an algorithm that converts the kilovoltage X-ray computed tomography (CT) number of a given material to its linear stopping power relative to water. Some materials present in kilovoltage scans of patients and simulation phantoms do not lie on the standard tissue conversion curve. The relative linear stopping powers (RLSPs) of 21 different tissue substitutes and positioning, registration, immobilization, and beamline materials were measured in beams of protons accelerated to energies of 155, 200, and 250 MeV; carbon ions accelerated to 290 MeV/n; and iron ions accelerated to 970 MeV/n. These same materials were scanned with both kilovoltage and megavoltage CT scanners to obtain their CT numbers. Measured RLSPs and CT numbers were compared with calculated and/or literature values. Relationships of RLSPs to physical densities, electronic densities, kilovoltage CT numbers, megavoltage CT numbers, and water equivalence values converted by a treatment planning system are given. Usage of CT numbers and substitution of measured values into treatment plans to provide accurate patient and phantom simulations are discussed.

  18. Application of curvelet transform for denoising of CT images

    NASA Astrophysics Data System (ADS)

    Ławicki, Tomasz; Zhirnova, Oxana

    2015-09-01

    The paper presents a method of noise reduction in CT images by the curvelet transform. Noise affects the ability to visualize pathologic qualities and the living tissues structure in CT. Noise in CT images depends on the amount of discrete x-ray photons reaching the detector. In the CT images, noise is responsible for visibility reduction the low contrast areas and objects. Noisy picture may not be properly interpreted by a physician, especially for the case of detection of pathological changes in tissues. The tests were performed with the Shepp-Logan test image with additive Gaussian noise.

  19. MR to CT Registration of Brains using Image Synthesis.

    PubMed

    Roy, Snehashis; Carass, Aaron; Jog, Amod; Prince, Jerry L; Lee, Junghoon

    2014-03-21

    Computed tomography (CT) is the standard imaging modality for patient dose calculation for radiation therapy. Magnetic resonance (MR) imaging (MRI) is used along with CT to identify brain structures due to its superior soft tissue contrast. Registration of MR and CT is necessary for accurate delineation of the tumor and other structures, and is critical in radiotherapy planning. Mutual information (MI) or its variants are typically used as a similarity metric to register MRI to CT. However, unlike CT, MRI intensity does not have an accepted calibrated intensity scale. Therefore, MI-based MR-CT registration may vary from scan to scan as MI depends on the joint histogram of the images. In this paper, we propose a fully automatic framework for MR-CT registration by synthesizing a synthetic CT image from MRI using a co-registered pair of MR and CT images as an atlas. Patches of the subject MRI are matched to the atlas and the synthetic CT patches are estimated in a probabilistic framework. The synthetic CT is registered to the original CT using a deformable registration and the computed deformation is applied to the MRI. In contrast to most existing methods, we do not need any manual intervention such as picking landmarks or regions of interests. The proposed method was validated on ten brain cancer patient cases, showing 25% improvement in MI and correlation between MR and CT images after registration compared to state-of-the-art registration methods.

  20. MR to CT registration of brains using image synthesis

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; Carass, Aaron; Jog, Amod; Prince, Jerry L.; Lee, Junghoon

    2014-03-01

    Computed tomography (CT) is the preferred imaging modality for patient dose calculation for radiation therapy. Magnetic resonance (MR) imaging (MRI) is used along with CT to identify brain structures due to its superior soft tissue contrast. Registration of MR and CT is necessary for accurate delineation of the tumor and other structures, and is critical in radiotherapy planning. Mutual information (MI) or its variants are typically used as a similarity metric to register MRI to CT. However, unlike CT, MRI intensity does not have an accepted calibrated intensity scale. Therefore, MI-based MR-CT registration may vary from scan to scan as MI depends on the joint histogram of the images. In this paper, we propose a fully automatic framework for MR-CT registration by synthesizing a synthetic CT image from MRI using a co-registered pair of MR and CT images as an atlas. Patches of the subject MRI are matched to the atlas and the synthetic CT patches are estimated in a probabilistic framework. The synthetic CT is registered to the original CT using a deformable registration and the computed deformation is applied to the MRI. In contrast to most existing methods, we do not need any manual intervention such as picking landmarks or regions of interests. The proposed method was validated on ten brain cancer patient cases, showing 25% improvement in MI and correlation between MR and CT images after registration compared to state-of-the-art registration methods.

  1. NETL CT Imaging Facility

    ScienceCinema

    None

    2016-07-12

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  2. Body CT (CAT Scan)

    MedlinePlus

    ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the CT ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  3. SU-E-J-24: Can Fiducial Marker-Based Setup Using ExacTrac Be An Alternative to Soft Tissue-Based Setup Using Cone-Beam CT for Prostate IMRT?

    SciTech Connect

    Tanabe, S; Utsunomiya, S; Abe, E; Aoyama, H; Satou, H; Sakai, H; Yamada, T

    2015-06-15

    Purpose: To assess an accuracy of fiducial maker-based setup using ExacTrac (ExT-based setup) as compared with soft tissue-based setup using Cone-beam CT (CBCT-based setup) for patients with prostate cancer receiving intensity-modulated radiation therapy (IMRT) for the purpose of investigating whether ExT-based setup can be an alternative to CBCT-based setup. Methods: The setup accuracy was analyzed prospectively for 7 prostate cancer patients with implanted three fiducial markers received IMRT. All patients were treated after CBCT-based setup was performed and corresponding shifts were recorded. ExacTrac images were obtained before and after CBCT-based setup. The fiducial marker-based shifts were calculated based on those two images and recorded on the assumption that the setup correction was carried out by fiducial marker-based auto correction. Mean and standard deviation of absolute differences and the correlation between CBCT and ExT shifts were estimated. Results: A total of 178 image dataset were analyzed. On the differences between CBCT and ExT shifts, 133 (75%) of 178 image dataset resulted in smaller differences than 3 mm in all dimensions. Mean differences in the anterior-posterior (AP), superior-inferior (SI), and left-right (LR) dimensions were 1.8 ± 1.9 mm, 0.7 ± 1.9 mm, and 0.6 ± 0.8 mm, respectively. The percentages of shift agreements within ±3 mm were 76% for AP, 90% for SI, and 100% for LR. The Pearson coefficient of correlation for CBCT and ExT shifts were 0.80 for AP, 0.80 for SI, and 0.65 for LR. Conclusion: This work showed that the accuracy of ExT-based setup was correlated with that of CBCT-based setup, implying that ExT-based setup has a potential ability to be an alternative to CBCT-based setup. The further work is to specify the conditions that ExT-based setup can provide the accuracy comparable to CBCT-based setup.

  4. Iterative image reconstruction in spectral CT

    NASA Astrophysics Data System (ADS)

    Hernandez, Daniel; Michel, Eric; Kim, Hye S.; Kim, Jae G.; Han, Byung H.; Cho, Min H.; Lee, Soo Y.

    2012-03-01

    Scan time of spectral-CTs is much longer than conventional CTs due to limited number of x-ray photons detectable by photon-counting detectors. However, the spectral pixel information in spectral-CT has much richer information on physiological and pathological status of the tissues than the CT-number in conventional CT, which makes the spectral- CT one of the promising future imaging modalities. One simple way to reduce the scan time in spectral-CT imaging is to reduce the number of views in the acquisition of projection data. But, this may result in poorer SNR and strong streak artifacts which can severely compromise the image quality. In this work, spectral-CT projection data were obtained from a lab-built spectral-CT consisting of a single CdTe photon counting detector, a micro-focus x-ray tube and scan mechanics. For the image reconstruction, we used two iterative image reconstruction methods, the simultaneous iterative reconstruction technique (SIRT) and the total variation minimization based on conjugate gradient method (CG-TV), along with the filtered back-projection (FBP) to compare the image quality. From the imaging of the iodine containing phantoms, we have observed that SIRT and CG-TV are superior to the FBP method in terms of SNR and streak artifacts.

  5. CT Image Presentations For Oral Surgery

    NASA Astrophysics Data System (ADS)

    Rhodes, Michael L.; Rothman, Stephen L. G.; Schwarz, Melvyn S.; Tivattanasuk, Eva S.

    1988-06-01

    Reformatted CT images of the mandible and maxilla are described as a planning aid to the surgical implantation of dental fixtures. Precisely scaled and cross referenced axial, oblique, CT generated panorex, and 3-D images are generated to help indicate where and how critical anatomic structures are positioned. This information guides the oral surgeon to those sites where dental implants have optimal osteotic support and least risk to sensitive neural tissue. Oblique images are generated at 1-2 mm increments along the arch of the mandible (or maxilla). Each oblique is oriented perpendicular to the local arch curvature. The adjoining five CT generated panorex views match the patient's mandibular (or maxilla) arch, with each of the views separated by twice the distance between axial CT slices. All views are mutually cross-referenced to show fine detail of the underlying mandibular (or maxilla) structure. Several exams are illustrated and benefit to subsequent surgery is assessed.

  6. Neurosarcoidosis on FET and FDG PET/CT.

    PubMed

    Chan, Mico; Hsiao, Edward

    2017-03-01

    O-(2-fluoroethyl)-L-tyrosine (FET) PET/CT is a promising imaging modality for brain tumor imaging because of its reported high sensitivity for biologically active tumor tissue. We present a case of biopsy-proven neurosarcoidosis showing FET uptake. It is an important cause of false-positive uptake on FET PET/CT.

  7. Intra-abdominal desmoplastic small round cell tumors: CT and FDG-PET/CT findings with histopathological association.

    PubMed

    Chen, Jingjing; Wu, Zengjie; Sun, Binbin; Li, Dacheng; Wang, Zhenguang; Liu, Fangjun; Hua, Hui

    2016-05-01

    Desmoplastic small round cell tumors (DSRCTs) are rare and aggressive malignant tumors. The aim of the present study was to analyze computed tomography (CT) and fluorodeoxyglucose positron emission tomography (FDG-PET)/CT imaging features of intra-abdominal desmoplastic DSRCT, and investigate the association of these features with histopathological results. The present study was a retrospective investigation of 4 patients with DSRCT. All patients underwent CT and dynamic CT, and 1 additionally underwent FDG-PET/CT scanning. Following a tumor resection, routine hematoxylin and eosin staining, and immunostaining, were performed and evaluated. Multiple large abdominopelvic masses were identified in all 4 patients; however, no indications of their site of origin were demonstrated. CT revealed soft-tissue masses with patchy foci of hypodense lesions. Contrast-enhanced CT revealed slightly or moderately heterogeneous enhancement of the lesions. Other observations from these patients included calcification (n=2), peritoneal seeding (n=3), hepatic metastasis (n=3), retroperitoneal lymphadenopathy (n=3) and ascites (n=2). FDG-PET/CT revealed multiple nodular increased FDG uptake in the abdominopelvic masses, and in the liver and peritoneum in 1 case. Intra-abdominal DSRCT demonstrated significant diagnostic characteristics on plain and contrast-enhanced CT. Multiple, bulky soft-tissue masses inside the peritoneal cavity, particularly in male adolescents and young adults, should be considered as potential cases of DSRCT. FDG-PET/CT techniques may be utilized to aid the staging of tumors.

  8. CT angiography - chest

    MedlinePlus

    Computed tomography angiography - thorax; CTA - lungs; Pulmonary embolism - CTA chest; Thoracic aortic aneurysm - CTA chest; Venous thromboembolism - CTA lung; Blood clot - CTA lung; Embolus - CTA lung; CT ...

  9. CT-guided percutaneous needle placement in forensic medicine.

    PubMed

    Hyodoh, Hideki; Shimizu, Jyunya; Mizuo, Keisuke; Okazaki, Shunichiro; Watanabe, Satoshi; Inoue, Hiromasa

    2015-03-01

    We have developed a technique of CT-guided needle placement in the destructed human body in forensic practice. A sixty-year-old male was found in a burned car and he was also destructed severely. Although blood was needed for the external examination, it was difficult to approach the vessels because of the severely burned condition of the cadaver. Thus, we attempted to obtain a blood sample from a vessel using a CT-guided technique. Postmortem CT demonstrated the presence of blood-containing vessels in the pelvis. Indeed, CT-guided needle placement had no difficulty with surface markers, table location, or depth measurement from the surface. CT-guide needle placement is a feasible and reliable technique, so that when the tissue/blood sample is at risk of being spoiled, CT-guided needle placement could be a substitute for conventional sampling techniques.

  10. CT Findings in Temporal Bone Osteoradionecrosis

    PubMed Central

    Ahmed, Salmaan; Gupta, Nakul; Hamilton, Jackson D.; Garden, Adam S.; Gidley, Paul W.; Ginsberg, Lawrence E.

    2014-01-01

    Purpose The goal of this study is to describe CT findings in patients with clinically proven temporal bone osteoradionecrosis (TB-ORN). Methods and materials CT scans of twenty patients were retrospectively evaluated for bony and soft tissue abnormalities. Clinical severity was graded based on level of therapy administered: mild (observation), moderate (antibiotics/hyperbaric oxygen), or severe (surgery). Results Radiation dose to the primary tumor ranged from 30 to 75.6 Gy. Time to onset of ORN from completion of radiation therapy was 2 to 22 years (median=7yrs). Clinical findings: Exposed bone=20/20, otorrhea=17/20, hearing loss=11/20, otalgia=10/20, facial nerve paralysis=2/20, gait imbalance=2/20. CT findings: EAC erosions=18/20, mastoid effusion=18/20, mastoid bony coalescence=5/20, enhancing soft tissue=6/20, soft tissue gas=6/20, temporomandibular joint/condylar erosion=3/20. 3 patients developed an abscess. Conclusion Mastoid effusion and EAC erosions are commonly seen with TB-ORN. Clinically moderate or severe cases of TB-ORN are more likely to demonstrate enhancing soft tissue (p=0.002), soft tissue gas (p=0.002), and temporomandibular joint involvement (p=0.07). PMID:24834883

  11. Utilizing time-lapse micro-CT-correlated bisphosphonate binding kinetics and soft tissue-derived input functions to differentiate site-specific changes in bone metabolism in vivo.

    PubMed

    Tower, R J; Campbell, G M; Müller, M; Glüer, C C; Tiwari, S

    2015-05-01

    The turnover of bone is a tightly regulated process between bone formation and resorption to ensure skeletal homeostasis. This process differs between bone types, with trabecular bone often associated with higher turnover than cortical bone. Analyses of bone by micro-computed tomography (micro-CT) reveal changes in structure and mineral content, but are limited in the study of metabolic activity at a single time point, while analyses of serum markers can reveal changes in bone metabolism, but cannot delineate the origin of any aberrant findings. To obtain a site-specific assessment of bone metabolic status, bisphosphonate binding kinetics were utilized. Using a fluorescently-labeled bisphosphonate, we show that early binding kinetics monitored in vivo using fluorescent molecular tomography (FMT) can monitor changes in bone metabolism in response to bone loss, stimulated by ovariectomy (OVX), or bone gain, resulting from treatment with the anabolic bone agent parathyroid hormone (PTH), and is capable of distinguishing different, metabolically distinct skeletal sites. Using time-lapse micro-CT, longitudinal bone turnover was quantified. The spine showed a significantly greater percent resorbing volume and surface in response to OVX, while mice treated with PTH showed significantly greater resorbing volume per bone surface in the spine and significantly greater forming surfaces in the knee. Correlation studies between binding kinetics and micro-CT suggest that forming surfaces, as assessed by time-lapse micro-CT, are preferentially reflected in the rate constant values while forming and resorbing bone volumes primarily affect plateau values. Additionally, we developed a blood pool correction method which now allows for quantitative multi-compartment analyses to be conducted using FMT. These results further expand our understanding of bisphosphonate binding and the use of bisphosphonate binding kinetics as a tool to monitor site-specific changes in bone metabolism in

  12. Computing effective dose in cardiac CT

    NASA Astrophysics Data System (ADS)

    Huda, Walter; Tipnis, Sameer; Sterzik, Alexander; Schoepf, U. Joseph

    2010-07-01

    We present a method of estimating effective doses in cardiac CT that accounts for selected techniques (kV mAs-1), anatomical location of the scan and patient size. A CT dosimetry spreadsheet (ImPACT CT Patient Dosimetry Calculator) was used to estimate effective doses (E) using ICRP 103 weighting factors for a 70 kg patient undergoing cardiac CT examinations. Using dose length product (DLP) for the same scans, we obtained values of E/DLP for three CT scanners used in cardiac imaging from two vendors. E/DLP ratios were obtained as a function of the anatomical location in the chest and for x-ray tube voltages ranging from 80 to 140 kV. We also computed the ratio of the average absorbed dose in a water cylinder modeling a patient weighing W kg to the corresponding average absorbed dose in a water cylinder equivalent to a 70 kg patient. The average E/DLP for a 16 cm cardiac heart CT scan was 26 µSv (mGy cm)-1, which is about 70% higher than the current E/DLP values used for chest CT scans (i.e. 14-17 µSv (mGy cm)-1). Our cardiac E/DLP ratios are higher because the cardiac region is ~30% more radiosensitive than the chest, and use of the ICRP 103 tissue weighting factors increases cardiac CT effective doses by ~30%. Increasing the x-ray tube voltage from 80 to 140 kV increases the E/DLP conversion factor for cardiac CT by 17%. For the same incident radiation at 120 kV, doses in 45 kg adults were ~22% higher than those in 70 kg adults, whereas doses in 120 kg adults were ~28% lower. Accurate estimates of the patient effective dose in cardiac CT should use ICRP 103 tissue weighting factors, and account for a choice of scan techniques (kV mAs-1), exposed scan region, as well as patient size.

  13. Mesentery neurilemmoma: CT, MRI and angiographic findings.

    PubMed

    Lao, Wilson T; Yang, Shih-Hung; Chen, Chi-Long; Chan, Wing P

    2011-01-01

    Mesenteric neurilemmoma is extremely rare. We present a case of a 45-year-old man with mesenteric neurilemmoma, with CT, MRI and angiographic findings. The patient was healthy and had had no symptoms previously. CT and MRI images revealed a 2.2-cm well-defined, soft-tissue mass adjacent to the posterior border of the left lobe of the liver. The tumor mass displayed a heterogenous low signal on T2-weighted image and peripheral enhancement after gadolinium administration. Angiography showed a hypervascular mass beneath the tail of pancreas, which was supplied by small branches of middle splenic artery. Histopathology revealed a mesentery neurilemmoma composed of spindle tumor cells.

  14. Computed Tomography (CT) -- Sinuses

    MedlinePlus

    ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, air-filled spaces within the bones of the face surrounding the ...

  15. Method for transforming CT images for attenuation correction in PET/CT imaging

    SciTech Connect

    Carney, Jonathan P.J.; Townsend, David W.; Rappoport, Vitaliy; Bendriem, Bernard

    2006-04-15

    A tube-voltage-dependent scheme is presented for transforming Hounsfield units (HU) measured by different computed tomography (CT) scanners at different x-ray tube voltages (kVp) to 511 keV linear attenuation values for attenuation correction in positron emission tomography (PET) data reconstruction. A Gammex 467 electron density CT phantom was imaged using a Siemens Sensation 16-slice CT, a Siemens Emotion 6-slice CT, a GE Lightspeed 16-slice CT, a Hitachi CXR 4-slice CT, and a Toshiba Aquilion 16-slice CT at kVp ranging from 80 to 140 kVp. All of these CT scanners are also available in combination with a PET scanner as a PET/CT tomograph. HU obtained for various reference tissue substitutes in the phantom were compared with the known linear attenuation values at 511 keV. The transformation, appropriate for lung, soft tissue, and bone, yields the function 9.6x10{sup -5}{center_dot}(HU+1000) below a threshold of {approx}50 HU and a{center_dot}(HU+1000)+b above the threshold, where a and b are fixed parameters that depend on the kVp setting. The use of the kVp-dependent scaling procedure leads to a significant improvement in reconstructed PET activity levels in phantom measurements, resolving errors of almost 40% otherwise seen for the case of dense bone phantoms at 80 kVp. Results are also presented for patient studies involving multiple CT scans at different kVp settings, which should all lead to the same 511 keV linear attenuation values. A linear fit to values obtained from 140 kVp CT images using the kVp-dependent scaling plotted as a function of the corresponding values obtained from 80 kVp CT images yielded y=1.003x-0.001 with an R{sup 2} value of 0.999, indicating that the same values are obtained to a high degree of accuracy.

  16. Comparison of CT and MR-CT Fusion for Prostate Post-Implant Dosimetry

    SciTech Connect

    Maletz, Kristina L.; Ennis, Ronald D.; Ostenson, Jason; Pevsner, Alexander; Kagen, Alexander; Wernick, Iddo

    2012-04-01

    Purpose: The use of T2 MR for postimplant dosimetry (PID) after prostate brachytherapy allows more anatomically accurate and precise contouring but does not readily permit seed identification. We developed a reproducible technique for performing MR-CT fusion and compared the resulting dosimetry to standard CT-based PID. Methods and Materials: CT and T1-weighted MR images for 45 patients were fused and aligned based on seed distribution. The T2-weighted MR image was then fused to the aligned T1. Reproducibility of the fusion technique was tested by inter- and intraobserver variability for 13 patients. Dosimetry was computed for the prostate as a whole and for the prostate divided into anterior and posterior sectors of the base, mid-prostate, and apex. Results: Inter- and intraobserver variability for the fusion technique showed less than 1% variation in D90. MR-CT fusion D90 and CT D90 were nearly equivalent for the whole prostate, but differed depending on the identification of superior extent of the base (p = 0.007) and on MR/CT prostate volume ratio (p = 0.03). Sector analysis showed a decrease in MR-CT fusion D90 in the anterior base (ratio 0.93 {+-}0.25, p < 0.05) and an increase in MR-CT fusion D90 in the apex (p < 0.05). The volume of extraprostatic tissue encompassed by the V100 is greater on MR than CT. Factors associated with this difference are the MR/CT volume ratio (p < 0.001) and the difference in identification of the inferior extent of the apex (p = 0.03). Conclusions: We developed a reproducible MR-CT fusion technique that allows MR-based dosimetry. Comparing the resulting postimplant dosimetry with standard CT dosimetry shows several differences, including adequacy of coverage of the base and conformity of the dosimetry around the apex. Given the advantage of MR-based tissue definition, further study of MR-based dosimetry is warranted.

  17. Development of contrast-enhanced rodent imaging using functional CT

    NASA Astrophysics Data System (ADS)

    Liang, Yun; Stantz, Keith M.; Krishnamurthi, Ganapathy; Steinmetz, Rosemary; Hutchins, Gary D.

    2003-05-01

    Micro-computed tomography (microCT) is capable of obtaining high-resolution images of skeletal tissues. However its image contrast among soft tissues remains inadequate for tumor detection. High speed functional computed tomography will be needed to image tumors by employing x-ray contrast medium. The functional microCT development will not only facilitate the image contrast enhancement among different tissues but also provide information of tumor physiology. To demonstrate the feasibility of functional CT in mouse imaging, sequential computed tomography is performed in mice after contrast material administration using a high-speed clinical CT scanner. Although the resolution of the clinical scanner is not sufficient to dissolve the anatomic details of rodents, bulky physiological parameters in major organs such as liver, kidney, pancreas, and ovaries (testicular) can be examined. For data analysis, a two-compartmental model is employed and implemented to characterize the tissue physiological parameters (regional blood flow, capillary permeability, and relative compartment volumes.) The measured contrast dynamics in kidneys are fitted with the compartmental model to derive the kidney tissue physiology. The study result suggests that it is feasible to extract mouse tissue physiology using functional CT imaging technology.

  18. Dual energy CT for attenuation correction with PET/CT

    SciTech Connect

    Xia, Ting; Alessio, Adam M.; Kinahan, Paul E.

    2014-01-15

    Purpose: The authors evaluate the energy dependent noise and bias properties of monoenergetic images synthesized from dual-energy CT (DECT) acquisitions. These monoenergetic images can be used to estimate attenuation coefficients at energies suitable for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging. This is becoming more relevant with the increased use of quantitative imaging by PET/CT and SPECT/CT scanners. There are, however, potential variations in the noise and bias of synthesized monoenergetic images as a function of energy. Methods: The authors used analytic approximations and simulations to estimate the noise and bias of synthesized monoenergetic images of water-filled cylinders with different shapes and the NURBS-based cardiac-torso (NCAT) phantom from 40 to 520 keV, the range of SPECT and PET energies. The dual-kVp spectra were based on the GE Lightspeed VCT scanner at 80 and 140 kVp with added filtration of 0.5 mm Cu. The authors evaluated strategies of noise suppression with sinogram smoothing and dose minimization with reduction of tube currents at the two kVp settings. The authors compared the impact of DECT-based attenuation correction with single-kVp CT-based attenuation correction on PET quantitation for the NCAT phantom for soft tissue and high-Z materials of bone and iodine contrast enhancement. Results: Both analytic calculations and simulations displayed the expected minimum noise value for a synthesized monoenergetic image at an energy between the mean energies of the two spectra. In addition the authors found that the normalized coefficient of variation in the synthesized attenuation map increased with energy but reached a plateau near 160 keV, and then remained constant with increasing energy up to 511 keV and beyond. The bias was minimal, as the linear attenuation coefficients of the synthesized monoenergetic images were within 2.4% of the known true values across the entire energy range

  19. Characterizing anatomical variability in breast CT images

    PubMed Central

    Metheany, Kathrine G.; Abbey, Craig K.; Packard, Nathan; Boone, John M.

    2008-01-01

    Previous work [Burgess , Med. Phys. 28, 419–437 (2001)] has shown that anatomical noise in projection mammography results in a power spectrum well modeled over a range of frequencies by a power law, and the exponent (β) of this power law plays a critical role in determining the size at which a growing lesion reaches the threshold for detection. In this study, the authors evaluated the power-law model for breast computed tomography (bCT) images, which can be thought of as thin sections through a three-dimensional (3D) volume. Under the assumption of a 3D power law describing the distribution of attenuation coefficients in the breast parenchyma, the authors derived the relationship between the power-law exponents of bCT and projection images and found it to be βsection=βproj−1. They evaluated this relationship on clinical images by comparing bCT images from a set of 43 patients to Burgess’ findings in mammography. They were able to make a direct comparison for 6 of these patients who had both a bCT exam and a digitized film-screen mammogram. They also evaluated segmented bCT images to investigate the extent to which the bCT power-law exponent can be explained by a binary model of attenuation coefficients based on the different attenuation of glandular and adipose tissue. The power-law model was found to be a good fit for bCT data over frequencies from 0.07to0.45cyc∕mm, where anatomical variability dominates the spectrum. The average exponent for bCT images was 1.86. This value is close to the theoretical prediction using Burgess’ published data for projection mammography and for the limited set of mammography data available from the authors’ patient sample. Exponents from the segmented bCT images (average value: 2.06) were systematically slightly higher than bCT images, with substantial correlation between the two (r=0.84). PMID:18975714

  20. CT Angiography (CTA)

    MedlinePlus

    ... CT Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ...

  1. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... scanners can perform the exam without stopping.) A computer creates separate images of the body area, called ...

  2. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... scanners can perform the exam without stopping.) A computer creates separate images of the arm area, called ...

  3. Computed Tomography (CT) -- Sinuses

    MedlinePlus Videos and Cool Tools

    ... to urinate; however, this is actually a contrast effect and subsides quickly. When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are ...

  4. Computed Tomography (CT) -- Head

    MedlinePlus Videos and Cool Tools

    ... to urinate; however, this is actually a contrast effect and subsides quickly. When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are ...

  5. Thoracic spine CT scan

    MedlinePlus

    ... Narrowing of the spine ( spinal stenosis ) Scoliosis Tumor Risks Risks of CT scans include: Exposure to radiation ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  6. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  7. Pediatric CT Scans

    Cancer.gov

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  8. Body CT (CAT Scan)

    MedlinePlus

    ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  9. Cardiac CT Scan

    MedlinePlus

    ... CT Scan Related Topics Aneurysm Coronary Calcium Scan Coronary Heart Disease Heart Attack Pulmonary Embolism Send a link to ... imaging test can help doctors detect or evaluate coronary heart disease, calcium buildup in the coronary arteries, problems with ...

  10. Evaluation of CT-based SUV normalization

    NASA Astrophysics Data System (ADS)

    Devriese, Joke; Beels, Laurence; Maes, Alex; Van de Wiele, Christophe; Pottel, Hans

    2016-09-01

    The purpose of this study was to determine patients’ lean body mass (LBM) and lean tissue (LT) mass using a computed tomography (CT)-based method, and to compare standardized uptake value (SUV) normalized by these parameters to conventionally normalized SUVs. Head-to-toe positron emission tomography (PET)/CT examinations were retrospectively retrieved and semi-automatically segmented into tissue types based on thresholding of CT Hounsfield units (HU). The following HU ranges were used for determination of CT-estimated LBM and LT (LBMCT and LTCT):  -180 to  -7 for adipose tissue (AT), -6 to 142 for LT, and 143 to 3010 for bone tissue (BT). Formula-estimated LBMs were calculated using formulas of James (1976 Research on Obesity: a Report of the DHSS/MRC Group (London: HMSO)) and Janmahasatian et al (2005 Clin. Pharmacokinet. 44 1051-65), and body surface area (BSA) was calculated using the DuBois formula (Dubois and Dubois 1989 Nutrition 5 303-11). The CT segmentation method was validated by comparing total patient body weight (BW) to CT-estimated BW (BWCT). LBMCT was compared to formula-based estimates (LBMJames and LBMJanma). SUVs in two healthy reference tissues, liver and mediastinum, were normalized for the aforementioned parameters and compared to each other in terms of variability and dependence on normalization factors and BW. Comparison of actual BW to BWCT shows a non-significant difference of 0.8 kg. LBMJames estimates are significantly higher than LBMJanma with differences of 4.7 kg for female and 1.0 kg for male patients. Formula-based LBM estimates do not significantly differ from LBMCT, neither for men nor for women. The coefficient of variation (CV) of SUV normalized for LBMJames (SUVLBM-James) (12.3%) was significantly reduced in liver compared to SUVBW (15.4%). All SUV variances in mediastinum were significantly reduced (CVs were 11.1-12.2%) compared to SUVBW (15.5%), except SUVBSA (15.2%). Only SUVBW and SUVLBM-James show

  11. CT of pituitary abscess

    SciTech Connect

    Fong, T.C.; Johns, R.D.; Long, M.; Myles, S.T.

    1985-06-01

    Pituitary abscess is a rare condition, with only 50 cases reported in the literature. Of those, 29 cases were well documented for analysis. Preoperative diagnosis of pituitary abscess is difficult. The computed tomographic (CT) appearance of pituitary abscess was first described in 1983; the abscess was depicted by axial images with coronal reconstruction. The authors recently encountered a case of pituitary abscess documented by direct coronal CT of the sella turcica.

  12. Internal noise in channelized Hotelling observer (CHO) study of detectability index-differential phase contrast CT vs. conventional CT

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi

    2014-03-01

    The channelized Hotelling observer (CHO) model, wherein internal noise plays an important role to account for the psychophysiological uncertainty in human's visual perception, has found extensive applications in the assessment of image quality in nuclear medicine, mammography and conventional CT. Recently, we extended its application to investigating the detectability index of differential phase contrast (DPC) CT-an emerging CT technology with the potential of increasing the capability in soft tissue differentiation. We found that the quantitative determination of internal noise in the CHO study of DPC-CT's detectability index should differ from that in the conventional CT. It is believed that the root cause of such a difference lies in the distinct noise spectra between the DPC-CT and conventional CT. In this paper, we present the preliminary results and investigate the adequate strategies to quantitatively determine the internal noise of CHO model for its application in the assessment of image quality in DPC-CT and its comparison with that of the conventional CT.

  13. Expression of MAGE-C1/CT7 and MAGE-C2/CT10 Predicts Lymph Node Metastasis in Melanoma Patients

    PubMed Central

    Mihic-Probst, Daniela; Seifert, Burkhardt; Soldini, Davide; Dummer, Reinhard; Knuth, Alexander; van den Broek, Maries; Moch, Holger

    2011-01-01

    MAGE-C1/CT7 and MAGE-C2/CT10 are members of the large MAGE family of cancer-testis (CT) antigens. CT antigens are promising targets for immunotherapy in cancer because their expression is restricted to cancer and germ line cells and a proportion of cancer patients presents with immune responses against CT antigens, which clearly demonstrates their immunogenicity. This study investigates the expression of MAGE-C1/CT7 and MAGE-C2/CT10 in primary and metastatic melanoma. Immunohistochemical staining of tissue microarrays that consisted of 59 primary malignant melanomas of the skin, 163 lymph node and distant melanoma metastases and 68 melanoma cell lines was performed. We found MAGE-C1/CT7 expression in 15 out of 50 (24%) primary melanomas and 15 out of 50 (24%) cell lines, whereas MAGE-C2/CT10 was detected in 17 out of 51 (33%) primary melanomas and 14 out of 68 (17%) cell lines. MAGE-C1/CT7 and MAGE-C2/CT10 were both detected in 40% of melanoma metastases. Patients with MAGE-C1/CT7 or MAGE-C2/CT10 positive primary melanoma had significantly more lymph node metastases (p = 0.005 and p<0.001, resp.). Prediction of lymph node metastasis by MAGE-C1/CT7 and MAGE-C2/CT10 was independent of tumor cell proliferation rate (Ki67 labeling index) in a multivariate analysis (p = 0.01). Our results suggest that the expression of MAGE-C1/CT7 and MAGE-C2/CT10 in primary melanoma is a potent predictor of sentinel lymph node metastasis. PMID:21738656

  14. CT guided interstitial therapy of pancreatic carcinoma

    SciTech Connect

    Haaga, J.R.; Owens, D.B.; Kellermeyer, R.W.; Shina, D.; Pilai, K.; Began, N.

    1987-11-01

    We describe the use of percutaneous CT guidance for localization and placement of /sup 192/Ir sources into a patient with pancreatic carcinoma. We have shown the feasibility of this procedure and the lack of complications which are probably due to minimal damage to tissue involved. Computed tomography is ideally suited for percutaneous implantation because it provides the most accurate method for needle placement within the abdomen.

  15. Iterative CT shading correction with no prior information

    NASA Astrophysics Data System (ADS)

    Wu, Pengwei; Sun, Xiaonan; Hu, Hongjie; Mao, Tingyu; Zhao, Wei; Sheng, Ke; Cheung, Alice A.; Niu, Tianye

    2015-11-01

    Shading artifacts in CT images are caused by scatter contamination, beam-hardening effect and other non-ideal imaging conditions. The purpose of this study is to propose a novel and general correction framework to eliminate low-frequency shading artifacts in CT images (e.g. cone-beam CT, low-kVp CT) without relying on prior information. The method is based on the general knowledge of the relatively uniform CT number distribution in one tissue component. The CT image is first segmented to construct a template image where each structure is filled with the same CT number of a specific tissue type. Then, by subtracting the ideal template from the CT image, the residual image from various error sources are generated. Since forward projection is an integration process, non-continuous shading artifacts in the image become continuous signals in a line integral. Thus, the residual image is forward projected and its line integral is low-pass filtered in order to estimate the error that causes shading artifacts. A compensation map is reconstructed from the filtered line integral error using a standard FDK algorithm and added back to the original image for shading correction. As the segmented image does not accurately depict a shaded CT image, the proposed scheme is iterated until the variation of the residual image is minimized. The proposed method is evaluated using cone-beam CT images of a Catphan©600 phantom and a pelvis patient, and low-kVp CT angiography images for carotid artery assessment. Compared with the CT image without correction, the proposed method reduces the overall CT number error from over 200 HU to be less than 30 HU and increases the spatial uniformity by a factor of 1.5. Low-contrast object is faithfully retained after the proposed correction. An effective iterative algorithm for shading correction in CT imaging is proposed that is only assisted by general anatomical information without relying on prior knowledge. The proposed method is thus practical

  16. Iterative CT shading correction with no prior information.

    PubMed

    Wu, Pengwei; Sun, Xiaonan; Hu, Hongjie; Mao, Tingyu; Zhao, Wei; Sheng, Ke; Cheung, Alice A; Niu, Tianye

    2015-11-07

    Shading artifacts in CT images are caused by scatter contamination, beam-hardening effect and other non-ideal imaging conditions. The purpose of this study is to propose a novel and general correction framework to eliminate low-frequency shading artifacts in CT images (e.g. cone-beam CT, low-kVp CT) without relying on prior information. The method is based on the general knowledge of the relatively uniform CT number distribution in one tissue component. The CT image is first segmented to construct a template image where each structure is filled with the same CT number of a specific tissue type. Then, by subtracting the ideal template from the CT image, the residual image from various error sources are generated. Since forward projection is an integration process, non-continuous shading artifacts in the image become continuous signals in a line integral. Thus, the residual image is forward projected and its line integral is low-pass filtered in order to estimate the error that causes shading artifacts. A compensation map is reconstructed from the filtered line integral error using a standard FDK algorithm and added back to the original image for shading correction. As the segmented image does not accurately depict a shaded CT image, the proposed scheme is iterated until the variation of the residual image is minimized. The proposed method is evaluated using cone-beam CT images of a Catphan©600 phantom and a pelvis patient, and low-kVp CT angiography images for carotid artery assessment. Compared with the CT image without correction, the proposed method reduces the overall CT number error from over 200 HU to be less than 30 HU and increases the spatial uniformity by a factor of 1.5. Low-contrast object is faithfully retained after the proposed correction. An effective iterative algorithm for shading correction in CT imaging is proposed that is only assisted by general anatomical information without relying on prior knowledge. The proposed method is thus practical

  17. Thyroid CT number and its relationship to iodine concentration

    SciTech Connect

    Iida, Y.; Konishi, J.; Harioka, T.; Misaki, T.; Endo, K.; Torizuka, K.

    1983-06-01

    Sixty-seven patients with thyroid disease and 24 normal controls were examined with computed tomography (CT). The mean CT number (Hounsfield units +/- SD) in the normal controls (118.1 +/- 12.2) was significantly higher (p < 0.001) than the mean CT number in patients with diseased thyroids, except for 2 cases of simple goiter (CT numbers 113, 132). The Graves disease (69.5 +/- 17.6) amd Hishimoto thyroiditis (61.4 +/- 9.1) were significaantly higher than those in patients with adenoma (41.7 +/- 10.6, p < 0.001), cyst (33.1 +/- 14.8, p < 0.001), or cancer (48.7 +/- 13, p < 0.01). In 14 patients studied, a significant correlation was observed between thyroid CT numbers and the iodine concentration of the tissue (r = 0.889; p < 0.001).

  18. CT of the normal and abnormal parametria in cervical cancer

    SciTech Connect

    Vick, C.W.; Walsh, J.W.; Wheelock, J.B.; Brewer, W.H.

    1984-09-01

    To evaluate CT criteria for differentiating a cervical cancer confined to the cervix from a lesion that invades the parametria, 16 patients with newly diagnosed, untreated cervical cancer were studied with CT. Twenty-five parameria were confined by radical hysterectomy, transvaginal parametrial fine-needle aspiration cytology, or excretory urography. In 17 tumor-positive parametria, CT findings associated with parametrial tumor invasion were: 1) irregularity or poor definition of the lateral cervical margins; 2) prominent parametrial soft-tissue strands; 3) obliteration of the periureteral fat plane; and 4) an eccentric parametrial soft-tissue mass. Irregularity of the cervical margins and prominent parametrial strands were seen most commonly with parametrial tumor invasion, but were also occasionally seen with parametrial inflammation. On the basis of the criteria developed in this report, CT may be used as an adjunct to the physical examination in differentiating stage I cervical cancer from more advanced disease in selected patients.

  19. [Prognostic significance of helical CT in patients with destructive pancreatitis].

    PubMed

    Bulanova, T V

    2000-01-01

    Spiral scanning computed tomography (CT) is able not only to image the pancreas and to evaluate its structure, but to interpret the status of the adjacent organs and tissues. CT symptoms of pancreatic necrotic changes and multiorgan failure were studied in the prospective follow-up of 47 patients with prior destructive pancreatitis (158 studies). CT differentially substantiated indications for choosing treatment policy for different forms of pancreatic lesions. The paper gives a quantitative assessment of necrotic pancreatic parencymatous areas and shows its prognostic value.

  20. Energy Dependence of Measured CT Numbers on Substituted Materials Used for CT Number Calibration of Radiotherapy Treatment Planning Systems

    PubMed Central

    Mahmoudi, Reza; Jabbari, Nasrollah; aghdasi, Mehdi; Khalkhali, Hamid Reza

    2016-01-01

    Introduction For accurate dose calculations, it is necessary to provide a correct relationship between the CT numbers and electron density in radiotherapy treatment planning systems (TPSs). The purpose of this study was to investigate the energy dependence of measured CT numbers on substituted materials used for CT number calibration of radiotherapy TPSs and the resulting errors in the treatment planning calculation doses. Materials and Methods In this study, we designed a cylindrical water phantom with different materials used as tissue equivalent materials for the simulation of tissues and obtaining the related CT numbers. For evaluating the effect of CT number variations of substituted materials due to energy changing of scanner (kVp) on the dose calculation of TPS, the slices of the scanned phantom at three kVp's were imported into the desired TPSs (MIRS and CorePLAN). Dose calculations were performed on two TPSs. Results The mean absolute percentage differences between the CT numbers of CT scanner and two treatment planning systems for all the samples were 3.22%±2.57% for CorePLAN and 2.88%±2.11% for MIRS. It was also found that the maximum absolute percentage difference between all of the calculated doses from each photon beam of linac (6 and 15 MV) at three kVp's was less than 1.2%. Discussion The present study revealed that, for the materials with effective low atomic number, the mean CT number increased with increasing energy, which was opposite for the materials with an effective high atomic number. We concluded that the tissue substitute materials had a different behavior in the energy ranges from 80 to 130 kVp. So, it is necessary to consider the energy dependence of the substitute materials used for the measurement or calibration of CT number for radiotherapy treatment planning systems. PMID:27391672

  1. Bone Windows for Distinguishing Malignant from Benign Primary Bone Tumors on FDG PET/CT.

    PubMed

    Costelloe, Colleen M; Chuang, Hubert H; Chasen, Beth A; Pan, Tinsu; Fox, Patricia S; Bassett, Roland L; Madewell, John E

    2013-01-01

    Objective. The default window setting on PET/CT workstations is soft tissue. This study investigates whether bone windowing and hybrid FDG PET/CT can help differentiate between malignant and benign primary bone tumors. Materials and methods. A database review included 98 patients with malignant (n=64) or benign primary bone (n=34) tumors. The reference standard was biopsy for malignancies and biopsy or >1 year imaging follow-up of benign tumors. Three radiologists and/or nuclear medicine physicians blinded to diagnosis and other imaging viewed the lesions on CT with bone windows (CT-BW) without and then with PET (PET/CT-BW), and separate PET-only images for malignancy or benignity. Three weeks later the tumors were viewed on CT with soft tissue windows (CT-STW) without and then with PET (PET/CT-STW). Results. Mean sensitivity and specificity for identifying malignancies included: CT-BW: 96%, 90%; CT-STW: 90%, 90%; PET/CT-BW: 95%, 85%, PET/CT-STW: 95%, 86% and PET-only: 96%, 75%, respectively. CT-BW demonstrated higher specificity than PET-only and PET/CT-BW (p=0.0005 and p=0.0103, respectively) and trended toward higher sensitivity than CT-STW (p=0.0759). Malignant primary bone tumors were more avid than benign lesions overall (p<0.0001) but the avidity of benign aggressive lesions (giant cell tumors and Langerhans Cell Histiocytosis) trended higher than the malignancies (p=0.08). Conclusion. Bone windows provided high specificity for distinguishing between malignant and benign primary bone tumors and are recommended when viewing FDG PET/CT.

  2. Clinical applications of dual-energy CT in head and neck imaging.

    PubMed

    Ginat, Daniel Thomas; Mayich, Michael; Daftari-Besheli, Laleh; Gupta, Rajiv

    2016-03-01

    Dual-energy CT provides insights into the material properties of the tissues and can differentiate between tissues that have similar attenuation on conventional, single energy CT imaging. It has several useful and promising applications in head and neck imaging that an otolaryngologist could use to deliver improved clinical care. These applications include metal artifact reduction, atherosclerotic plaque and tumor characterization, detection of parathyroid lesions, and delineation of paranasal sinus ventilation. Dual-energy CT can potentially improve image quality, reduce radiation dose, and provide specific diagnostic information for certain head and neck lesions. This article reviews some current and potential otolaryngology applications of dual-energy CT.

  3. State of the Art of Micro-CT Applications in Dental Research

    PubMed Central

    Swain, Michael V; Xue, Jing

    2009-01-01

    This review highlights the recent advances in X-ray microcomputed tomography (Micro-CT) applied in dental research. It summarizes Micro-CT applications in measurement of enamel thickness, root canal morphology, evaluation of root canal preparation, craniofacial skeletal structure, micro finite element modeling, dental tissue engineering, mineral density of dental hard tissues and about dental implants. Details of studies in each of these areas are highlighted along with the advantages of Micro-CT, and finally a summary of the future applications of Micro-CT in dental research is given. PMID:20690421

  4. Calibration free beam hardening correction for cardiac CT perfusion imaging

    NASA Astrophysics Data System (ADS)

    Levi, Jacob; Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    Myocardial perfusion imaging using CT (MPI-CT) and coronary CTA have the potential to make CT an ideal noninvasive gate-keeper for invasive coronary angiography. However, beam hardening artifacts (BHA) prevent accurate blood flow calculation in MPI-CT. BH Correction (BHC) methods require either energy-sensitive CT, not widely available, or typically a calibration-based method. We developed a calibration-free, automatic BHC (ABHC) method suitable for MPI-CT. The algorithm works with any BHC method and iteratively determines model parameters using proposed BHA-specific cost function. In this work, we use the polynomial BHC extended to three materials. The image is segmented into soft tissue, bone, and iodine images, based on mean HU and temporal enhancement. Forward projections of bone and iodine images are obtained, and in each iteration polynomial correction is applied. Corrections are then back projected and combined to obtain the current iteration's BHC image. This process is iterated until cost is minimized. We evaluate the algorithm on simulated and physical phantom images and on preclinical MPI-CT data. The scans were obtained on a prototype spectral detector CT (SDCT) scanner (Philips Healthcare). Mono-energetic reconstructed images were used as the reference. In the simulated phantom, BH streak artifacts were reduced from 12+/-2HU to 1+/-1HU and cupping was reduced by 81%. Similarly, in physical phantom, BH streak artifacts were reduced from 48+/-6HU to 1+/-5HU and cupping was reduced by 86%. In preclinical MPI-CT images, BHA was reduced from 28+/-6 HU to less than 4+/-4HU at peak enhancement. Results suggest that the algorithm can be used to reduce BHA in conventional CT and improve MPI-CT accuracy.

  5. Imaging lobular breast carcinoma: comparison of synchrotron radiation DEI-CT technique with clinical CT, mammography and histology

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Bravin, A.; Keyriläinen, J.; Fernández, M.; Suortti, P.; Thomlinson, W.; Tenhunen, M.; Virkkunen, P.; Karjalainen-Lindsberg, M.-L.

    2004-01-01

    Different modalities for imaging cancer-bearing breast tissue samples are described and compared. The images include clinical mammograms and computed tomography (CT) images, CT images with partly coherent synchrotron radiation (SR), and CT and radiography images taken with SR using the diffraction enhanced imaging (DEI) method. The images are evaluated by a radiologist and compared with histopathological examination of the samples. Two cases of lobular carcinoma are studied in detail. The indications of cancer are very weak or invisible in the conventional images, but the morphological changes due to invasion of cancer become pronounced in the images taken by the DEI method. The strands penetrating adipose tissue are seen clearly in the DEI-CT images, and the histopathology confirms that some strands contain the so-called 'Indian file' formations of cancer cells. The radiation dose is carefully measured for each of the imaging modalities. The mean glandular dose (MGD) for 50% glandular breast tissue is about 1 mGy in conventional mammography and less than 0.25 mGy in projection DEI, while in the clinical CT imaging the MGD is very high, about 45 mGy. The entrance dose of 95 mGy in DEI-CT imaging gives rise to an MGD of 40 mGy, but the dose may be reduced by an order of magnitude, because the contrast is very large in most images.

  6. Determination of CT-to-density conversion relationship for image-based treatment planning systems.

    PubMed

    Saw, Cheng B; Loper, Alphonse; Komanduri, Krishna; Combine, Tony; Huq, Saiful; Scicutella, Carol

    2005-01-01

    The implementation of tissue inhomogeneity correction in image-based treatment planning will improve the accuracy of radiation dose calculations for patients undergoing external-beam radiotherapy. Before the tissue inhomogeneity correction can be applied, the relationship between the computed tomography (CT) value and density must be established. This tissue characterization relationship allows the conversion of CT value in each voxel of the CT images into density for use in the dose calculations. This paper describes the proper procedure of establishing the CT value to density conversion relationship. A tissue characterization phantom with 17 inserts made of different materials was scanned using a GE Lightspeed Plus CT scanner (120 kVp). These images were then downloaded into the Eclipse and Pinnacle treatment planning systems. At the treatment planning workstation, the axial images were retrieved to determine the CT value of the inserts. A region of interest was drawn on the central portion of the insert and the mean CT value and its standard deviation were determined. The mean CT value was plotted against the density of the tissue inserts and fitted with bilinear equations. A new set of CT values vs. densities was generated from the bilinear equations and then entered into the treatment planning systems. The need to obtain CT values through the treatment planning system is very clear. The 2 treatment planning systems use different CT value ranges, one from -1024 to 3071 and the other from 0 to 4096. If the range is correct, it would result in inappropriate use of the conversion curve. In addition to the difference in the range of CT values, one treatment planning system uses physical density, while the other uses relative electron density.

  7. CT Perfusion of the Head

    MedlinePlus

    ... the machine as the actual CT scanning is performed. Depending on the type of CT scan, the machine may make several passes. The contrast material will then be injected through an intravenous line ( ...

  8. CT and Ultrasound Guided Stereotactic High Intensity Focused Ultrasound (HIFU)

    SciTech Connect

    Wood, Bradford J.; Frenkel, V.; Viswanathan, A.; Dromi, S.; Oh, K.; Kam, A.; Li, K. C. P.; Yanof, J.; Bauer, C.; Kruecker, J.; Seip, R.

    2006-05-08

    To demonstrate the feasibility of CT and B-mode Ultrasound (US) targeted HIFU, a prototype coaxial focused ultrasound transducer was registered and integrated to a CT scanner. CT and diagnostic ultrasound were used for HIFU targeting and monitoring, with the goals of both thermal ablation and non-thermal enhanced drug delivery. A 1 megahertz coaxial ultrasound transducer was custom fabricated and attached to a passive position-sensing arm and an active six degree-of-freedom robotic arm via a CT stereotactic frame. The outer therapeutic transducer with a 10 cm fixed focal zone was coaxially mounted to an inner diagnostic US transducer (2-4 megahertz, Philips Medical Systems). This coaxial US transducer was connected to a modified commercial focused ultrasound generator (Focus Surgery, Indianapolis, IN) with a maximum total acoustic power of 100 watts. This pre-clinical paradigm was tested for ability to heat tissue in phantoms with monitoring and navigation from CT and live US. The feasibility of navigation via image fusion of CT with other modalities such as PET and MRI was demonstrated. Heated water phantoms were tested for correlation between CT numbers and temperature (for ablation monitoring). The prototype transducer and integrated CT/US imaging system enabled simultaneous multimodality imaging and therapy. Pre-clinical phantom models validated the treatment paradigm and demonstrated integrated multimodality guidance and treatment monitoring. Temperature changes during phantom cooling corresponded to CT number changes. Contrast enhanced or non-enhanced CT numbers may potentially be used to monitor thermal ablation with HIFU. Integrated CT, diagnostic US, and therapeutic focused ultrasound bridges a gap between diagnosis and therapy. Preliminary results show that the multimodality system may represent a relatively inexpensive, accessible, and simple method of both targeting and monitoring HIFU effects. Small animal pre-clinical models may be translated to large

  9. Technical aspects of CT angiography.

    PubMed

    Kuszyk, B S; Fishman, E K

    1998-10-01

    The basic tasks of spiral CT acquisition, image processing, and image display are the foundations underlying CT angiography regardless of the anatomic region of interest. Volume rendering is a rapidly emerging image processing technique for creating three-dimensional (3D) images from CT datasets, which has important advantages over other 3D rendering techniques including maximum intensity projection and surface rendering. This articles reviews the techniques that are commonly used in CT angiography and key considerations for optimization.

  10. Seventh-generation CT

    NASA Astrophysics Data System (ADS)

    Besson, G. M.

    2016-03-01

    A new dual-drum CT system architecture has been recently introduced with the potential to achieve significantly higher temporal resolution than is currently possible in medical imaging CT. The concept relies only on known technologies; in particular rotation speeds several times higher than what is possible today could be achieved leveraging typical x-ray tube designs and capabilities. However, the architecture lends itself to the development of a new arrangement of x-ray sources in a toroidal vacuum envelope containing a rotating cathode ring and a (optionally rotating) shared anode ring to potentially obtain increased individual beam power as well as increase total exposure per rotation. The new x-ray source sub-system design builds on previously described concepts and could make the provision of multiple conventional high-power cathodes in a CT system practical by distributing the anode target between the cathodes. In particular, relying on known magnetic-levitation technologies, it is in principle possible to more than double the relative speed of the electron-beam with respect to the target, thus potentially leading to significant individual beam power increases as compared to today's state-of-the-art. In one embodiment, the proposed design can be naturally leveraged by the dual-drum CT concept previously described to alleviate the problem of arranging a number of conventional rotating anode-stem x-ray tubes and power conditioners on the limited space of a CT gantry. In another embodiment, a system with three cathodes is suggested leveraging the architecture previously proposed by Franke.

  11. Substitute CT generation from a single ultra short time echo MRI sequence: preliminary study

    NASA Astrophysics Data System (ADS)

    Ghose, Soumya; Dowling, Jason A.; Rai, Robba; Liney, Gary P.

    2017-04-01

    In MR guided radiation therapy planning both MR and CT images for a patient are acquired and co-registered to obtain a tissue specific HU map. Generation of the HU map directly from the MRI would eliminate the CT acquisition and may improve radiation therapy planning. In this preliminary study of substitute CT (sCT) generation, two porcine leg phantoms were scanned using a 3D ultrashort echo time (PETRA) sequence and co-registered to corresponding CT images to build tissue specific regression models. The model was created from one co-registered CT-PETRA pair to generate the sCT for the other PETRA image. An expectation maximization based clustering was performed on the co-registered PETRA image to identify the soft tissues, dense bone and air class membership probabilities. A tissue specific non linear regression model was built from one registered CT-PETRA pair dataset to predict the sCT of the second PETRA image in a two-fold cross validation schema. A complete substitute CT is generated in 3 min. The mean absolute HU error for air was 0.3 HU, bone was 95 HU, fat was 30 HU and for muscle it was 10 HU. The mean surface reconstruction error for the bone was 1.3 mm. The PETRA sequence enabled a low mean absolute surface distance for the bone and a low HU error for other classes. The sCT generated from a single PETRA sequence shows promise for the generation of fast sCT for MRI based radiation therapy planning.

  12. Dual Energy and Low kVp CT in the Abdomen

    PubMed Central

    Yeh, Benjamin M.; Shepherd, John A; Wang, Zhen J; Teh, Hui Seong; Hartman, Robert; Prevrhal, Sven

    2010-01-01

    Low kVp settings provide high conspicuity of contrast materials at CT but may result in high image noise, particularly in larger patients. Material decomposition at dual energy CT can differentiate renal stones by their composition, quantify tissue iron stores, improve the detection of pathologic hyperenhancement, and reduce contrast material and radiation dose compared to conventional CT. Further clinical research and technique refinement will be needed as the usage of these exiciting technologies spreads. PMID:19542394

  13. Gastrointestinal Stromal Tumor Showing Intense Tracer Uptake on PSMA PET/CT.

    PubMed

    Noto, Benjamin; Weckesser, Matthias; Buerke, Boris; Pixberg, Michaela; Avramovic, Nemanja

    2017-03-01

    A 70-year-old man with suspected prostate cancer was referred for Ga-PSMA-HBED-CC PET/CT (short PSMA PET/CT) for staging of tumor extent. Apart from vivid tracer uptake in the prostate gland and osseous metastasis, PSMA PET/CT revealed a large soft tissue mass with calcifications in the left upper abdomen showing intense tracer uptake. Histologic examination revealed the mass to be a gastrointestinal stromal tumor.

  14. Automated lung segmentation of low resolution CT scans of rats

    NASA Astrophysics Data System (ADS)

    Rizzo, Benjamin M.; Haworth, Steven T.; Clough, Anne V.

    2014-03-01

    Dual modality micro-CT and SPECT imaging can play an important role in preclinical studies designed to investigate mechanisms, progression, and therapies for acute lung injury in rats. SPECT imaging involves examining the uptake of radiopharmaceuticals within the lung, with the hypothesis that uptake is sensitive to the health or disease status of the lung tissue. Methods of quantifying lung uptake and comparison of right and left lung uptake generally begin with identifying and segmenting the lung region within the 3D reconstructed SPECT volume. However, identification of the lung boundaries and the fissure between the left and right lung is not always possible from the SPECT images directly since the radiopharmaceutical may be taken up by other surrounding tissues. Thus, our SPECT protocol begins with a fast CT scan, the lung boundaries are identified from the CT volume, and the CT region is coregistered with the SPECT volume to obtain the SPECT lung region. Segmenting rat lungs within the CT volume is particularly challenging due to the relatively low resolution of the images and the rat's unique anatomy. Thus, we have developed an automated segmentation algorithm for low resolution micro-CT scans that utilizes depth maps to detect fissures on the surface of the lung volume. The fissure's surface location is in turn used to interpolate the fissure throughout the lung volume. Results indicate that the segmentation method results in left and right lung regions consistent with rat lung anatomy.

  15. Tissue-like phantoms

    DOEpatents

    Frangioni, John V.; De Grand, Alec M.

    2007-10-30

    The invention is based, in part, on the discovery that by combining certain components one can generate a tissue-like phantom that mimics any desired tissue, is simple and inexpensive to prepare, and is stable over many weeks or months. In addition, new multi-modal imaging objects (e.g., beads) can be inserted into the phantoms to mimic tissue pathologies, such as cancer, or merely to serve as calibration standards. These objects can be imaged using one, two, or more (e.g., four) different imaging modalities (e.g., x-ray computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and near-infrared (NIR) fluorescence) simultaneously.

  16. Flat-panel volume CT: fundamental principles, technology, and applications.

    PubMed

    Gupta, Rajiv; Cheung, Arnold C; Bartling, Soenke H; Lisauskas, Jennifer; Grasruck, Michael; Leidecker, Christianne; Schmidt, Bernhard; Flohr, Thomas; Brady, Thomas J

    2008-01-01

    Flat-panel volume computed tomography (CT) systems have an innovative design that allows coverage of a large volume per rotation, fluoroscopic and dynamic imaging, and high spatial resolution that permits visualization of complex human anatomy such as fine temporal bone structures and trabecular bone architecture. In simple terms, flat-panel volume CT scanners can be thought of as conventional multidetector CT scanners in which the detector rows have been replaced by an area detector. The flat-panel detector has wide z-axis coverage that enables imaging of entire organs in one axial acquisition. Its fluoroscopic and angiographic capabilities are useful for intraoperative and vascular applications. Furthermore, the high-volume coverage and continuous rotation of the detector may enable depiction of dynamic processes such as coronary blood flow and whole-brain perfusion. Other applications in which flat-panel volume CT may play a role include small-animal imaging, nondestructive testing in animal survival surgeries, and tissue-engineering experiments. Such versatility has led some to predict that flat-panel volume CT will gain importance in interventional and intraoperative applications, especially in specialties such as cardiac imaging, interventional neuroradiology, orthopedics, and otolaryngology. However, the contrast resolution of flat-panel volume CT is slightly inferior to that of multidetector CT, a higher radiation dose is needed to achieve a comparable signal-to-noise ratio, and a slower scintillator results in a longer scanning time.

  17. Comparison of FDG-PET/CT and CT for Delineation of Lumpectomy Cavity for Partial Breast Irradiation

    SciTech Connect

    Ford, Eric C. Lavely, William C.; Frassica, Deborah A.; Myers, Lee T.; Asrari, Fariba; Wahl, Richard L.; Zellars, Richard C.

    2008-06-01

    Purpose: The success of partial breast irradiation critically depends on proper target localization. We examined the use of fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) for improved lumpectomy cavity (LC) delineation and treatment planning. Methods and Materials: Twelve breast cancer patients underwent FDG-PET/CT on a GE Discovery scanner with a median time from surgery to PET/CT of 49 days. The LC was contoured on the CT scan by a radiation oncologist and, together with a nuclear medicine physician, on the PET/CT scan. The volumes were calculated and compared in each patient. Treatment planning target volumes (PTVs) were calculated by expanding the margin 2 cm beyond the LC, maintaining a 5-mm margin from the skin and chest wall, and the treatment plans were evaluated. In addition, a study with a patient-like phantom was conducted to evaluate the effect that the window/level settings might have on contouring. Results: The margin of the LC was well visualized on all FDG-PET images. The phantom results indicated that the difference between the known volume and the FDG-PET-delineated volume was <10%, regardless of the window/level settings. The PET/CT volumes were larger than the CT volumes in all cases (median volume ratio, 1.68; range, 1.24-2.45; p = 0.004). The PET/CT-based PTVs were also larger than the CT-based PTV (median volume ratio, 1.16; range, 1.08-1.64; p = 0.006). In 9 of 12 patients, a CT-based treatment plan did not provide adequate coverage of the PET/CT-based PTV (99% of the PTV received <95% of the prescribed dose), resulting in substantial cold spots in some plans. In these cases, treatment plans were generated which were specifically designed to cover the larger PET/CT-based PTV. Although these plans showed an increased dose to the normal tissues, the increases were modest: the non-target breast volume receiving {>=}50 Gy, lung volume receiving {>=}30 Gy, and heart volume receiving {>=}5 Gy increased by 5

  18. Dosimetric feasibility of cone-beam CT-based treatment planning compared to CT-based treatment planning

    SciTech Connect

    Yoo, Sua . E-mail: sua.yoo@duke.edu; Yin, F.-F.

    2006-12-01

    Purpose: Cone-beam computed tomography (CBCT) images are currently used for positioning verification. However, it is yet unknown whether CBCT could be used in dose calculation for replanning in adaptive radiation therapy. This study investigates the dosimetric feasibility of CBCT-based treatment planning. Methods and Materials: Hounsfield unit (HU) values and profiles of Catphan, homogeneous/inhomogeneous phantoms, and various tissue regions of patients in CBCT images were compared to those in CT. The dosimetric consequence of the HU variation was investigated by comparing CBCT-based treatment plans to conventional CT-based plans for both phantoms and patients. Results: The maximum HU difference between CBCT and CT of Catphan was 34 HU in the Teflon. The differences in other materials were less than 10 HU. The profiles for the homogeneous phantoms in CBCT displayed reduced HU values up to 150 HU in the peripheral regions compared to those in CT. The scatter and artifacts in CBCT became severe surrounding inhomogeneous tissues with reduced HU values up to 200 HU. The MU/cGy differences were less than 1% for most phantom cases. The isodose distributions between CBCT-based and CT-based plans agreed very well. However, the discrepancy was larger when CBCT was scanned without a bowtie filter than with bowtie filter. Also, up to 3% dosimetric error was observed in the plans for the inhomogeneous phantom. In the patient studies, the discrepancies of isodose lines between CT-based and CBCT-based plans, both 3D and IMRT, were less than 2 mm. Again, larger discrepancy occurred for the lung cancer patients. Conclusion: This study demonstrated the feasibility of CBCT-based treatment planning. CBCT-based treatment plans were dosimetrically comparable to CT-based treatment plans. Dosimetric data in the inhomogeneous tissue regions should be carefully validated.

  19. Multi-modal CT in Stroke Imaging: New Concepts

    PubMed Central

    Ledezma, Carlos J.; Wintermark, Max

    2009-01-01

    A multimodal CT protocol provides a comprehensive non-invasive survey of acute stroke patients with accurate demonstration of the site of arterial occlusion and its hemodynamic tissue status. It combines widespread availability with the ability to provide functional characterization of cerebral ischemia, and could potentially allow more accurate selection of candidates for acute stroke reperfusion therapy. PMID:19195537

  20. CT120: A New Potential Target for c-Myc in Head and Neck Cancers

    PubMed Central

    Baltaci, Elif; Seyhan, Betül; Baykara, Onur; Buyru, Nur

    2017-01-01

    Background: CT120 is a universally expressed protein with seven transmembrane domains. It functions in cell proliferation, survival and apoptosis by activating Raf/MEK/ERK and PI3K/Akt signaling pathways. Evidence suggests that CT120 plays important roles in lung carcinogenesis and oncogenic pathway activation. c-Myc is an important transcription factor modulating cell progression, apoptosis and cellular transformation. Previous studies have shown that MYC gene is amplified in many types of cancer including head and neck squamous cell carcinoma (HNSCC). Myc can regulate expression of many genes by binding to E-boxes. The aim of this study was to investigate the relationship between c-Myc protein and CT120 gene. Methods: Tumor and normal tissue samples from 50 patients with HNSCC were investigated with chromatin immunoprecipitation assay (ChIP), Illumina MiSeq, bisulphite sequencing and qRT-PCR. Results: c-Myc binds to all E-boxes except E-box 5 on CT120 promoter. The CpG dinucleotides were found to be partially methylated in all tumor and normal tissue samples. Bisulphite sequencing showed a 10% down-regulation in the methylation levels of the tumor tissues. CT120 gene was hypomethylated and up-regulated in 56% of the tumor tissue samples. Expression of c-Myc was significantly higher in tumor tissues than in non-cancerous tissue samples. MYC was overexpressed in 68% of the tumor tissue samples compared to normal tissues. The mean MYC levels were 2.42-fold higher in the tumor tissue samples. In 48% of the tumor tissues, MYC and CT120A mRNA were up- or down-regulated simultaneously (p<0.001). Conclusion: We show that CT120 gene is a target of c-Myc and it contributes to cancer progression in HNSCC. PMID:28382151

  1. SU-E-J-187: Individually Optimized Contrast-Enhancement 4D-CT for Pancreatic Adenocarcinoma in Radiotherapy Simulation

    SciTech Connect

    Xue, M; Patel, K; Regine, W; Lane, B; D'Souza, W; Lu, W; Klahr, P

    2014-06-01

    Purpose: To study the feasibility of individually optimized contrastenhancement (CE) 4D-CT for pancreatic adenocarcinoma (PDA) in radiotherapy simulation. To evaluate the image quality and contrast enhancement of tumor in the CE 4D-CT, compared to the clinical standard of CE 3D-CT and 4D-CT. Methods: In this IRB-approved study, each of the 7 PDA patients enrolled underwent 3 CT scans: a free-breathing 3D-CT with contrast (CE 3D-CT) followed by a 4D-CT without contrast (4D-CT) in the first study session, and a 4D-CT with individually synchronized contrast injection (CE 4D-CT) in the second study session. In CE 4D-CT, the time of full contrast injection was determined based on the time of peak enhancement for the test injection, injection rate, table speed, and longitudinal location and span of the pancreatic region. Physicians contoured both the tumor (T) and the normal pancreatic parenchyma (P) on the three CTs (end-of-exhalation for 4D-CT). The contrast between the tumor and normal pancreatic tissue was computed as the difference of the mean enhancement level of three 1 cm3 regions of interests in T and P, respectively. Wilcoxon rank sum test was used to statistically compare the scores and contrasts. Results: In qualitative evaluations, both CE 3D-CT and CE 4D-CT scored significantly better than 4D-CT (4.0 and 3.6 vs. 2.6). There was no significant difference between CE 3D-CT and CE 4D-CT. In quantitative evaluations, the contrasts between the tumor and the normal pancreatic parenchyma were 0.6±23.4, −2.1±8.0, and −19.6±28.8 HU, in CE 3D-CT, 4D-CT, and CE 4D-CT, respectively. Although not statistically significant, CE 4D-CT achieved better contrast enhancement between the tumor and the normal pancreatic parenchyma than both CE 3D-CT and 4DCT. Conclusion: CE 4D-CT achieved equivalent image quality and better contrast enhancement between tumor and normal pancreatic parenchyma than the clinical standard of CE 3D-CT and 4D-CT. This study was supported in part

  2. Functional CT imaging of prostate cancer

    NASA Astrophysics Data System (ADS)

    Henderson, Elizabeth; Milosevic, Michael F.; Haider, Masoom A.; Yeung, Ivan W. T.

    2003-09-01

    The purpose of this paper is to investigate the distribution of blood flow (F), mean capillary transit time (Tc), capillary permeability (PS) and blood volume (vb) in prostate cancer using contrast-enhanced CT. Nine stage T2-T3 prostate cancer patients were enrolled in the study. Following bolus injection of a contrast agent, a time series of CT images of the prostate was acquired. Functional maps showing the distribution of F, Tc, PS and vb within the prostate were generated using a distributed parameter tracer kinetic model, the adiabatic approximation to the tissue homogeneity model. The precision of the maps was assessed using covariance matrix analysis. Finally, maps were compared to the findings of standard clinical investigations. Eight of the functional maps demonstrated regions of increased F, PS and vb, the locations of which were consistent with the results of standard clinical investigations. However, model parameters other than F could only be measured precisely within regions of high F. In conclusion functional CT images of cancer-containing prostate glands demonstrate regions of elevated F, PS and vb. However, caution should be used when applying a complex tracer kinetic model to the study of prostate cancer since not all parameters can be measured precisely in all areas.

  3. CT features of nonfunctioning islet cell carcinoma

    SciTech Connect

    Eelkema, E.A.; Stephens, D.H.; Ward, E.M.; Sheedy, P.F. II

    1984-11-01

    To determine the computed tomographic (CT) characteristics of nonfunctioning islet cell carcinoma of the pancreas, the CT scans of 27 patients with that disease were reviewed. The pancreatic tumor was identified as a mass in 26 patients (96%) Of the 25 tumors evaluated with contrast enhancement, 20 became partially diffusely hyperdense relative to nearby normal pancreatic tissue. Hepatic metastases were identified in 15 patients (56%), regional lymphadenopathy in 10 (37%), atrophy of the gland proximal to the tumor in six (22%), dilatation of the biliary ducts in five (19%), and dilatation of the pancreatic duct in four (15%). The CT appearances of the nonfunctioning islet cell tumors were compared with those of 100 ordinary (ductal) pancreatic adenocarcinomas. Although the two types of tumors were sometimes indistinguishable, features found to be more characteristic of islet cell carcinoma included a pancreatic mass of unusually large size, calcification within the tumor, and contrast enhancement of either the primary tumor or hepatic metastases. Involvement of the celiac axis or proximal superior mesenteric artery was limited to ductal carcinoma.

  4. Expression of cancer testis antigen CT45 in classical Hodgkin lymphoma and other B-cell lymphomas.

    PubMed

    Chen, Yao-Tseng; Chadburn, Amy; Lee, Peishan; Hsu, Melinda; Ritter, Erika; Chiu, April; Gnjatic, Sacha; Pfreundschuh, Michael; Knowles, Daniel M; Old, Lloyd J

    2010-02-16

    We have shown previously that cancer/testis (CT) antigen, CT45, is expressed in various epithelial cancers at a frequency of <5% to approximately 35%. In this study, the protein expression of CT45 was examined in non-Hodgkin B-cell lymphomas and classical Hodgkin lymphoma by immunohistochemical analysis. Serological response to CT45 was also evaluated by ELISA using CT45 recombinant protein and sera from patients with Hodgkin lymphoma. None of the 80 low-grade B-cell lymphomas, including chronic lymphocytic leukemia/small lymphocytic lymphoma, follicular lymphoma, and mantle cell lymphoma, expressed CT45. In comparison, CT45 was expressed in 28 of 126 (22%) diffuse large B-cell lymphomas (DLBCL). A remarkably high percentage (42/72, 58%) of classical Hodgkin lymphoma contained CT45-positive Reed-Sternberg cells. Nodular sclerosis and mixed-cellularity subtypes had similar frequency of CT45 expression, but most EBV-positive cases were CT45 negative. Gray-zone lymphoma (cases with features of both DLBCL and classical Hodgkin lymphoma) also showed frequent (64%) CT45 expression. Evaluation of reactive lymphoid tissues showed scattered CT45-positive lymphocytes in a single case of florid follicular hyperplasia, raising the possibility that this case was an evolving malignancy. Despite frequent CT45 expression, only 1 of 67 Hodgkin lymphoma patients had detectable anti-CT45 antibodies in the serum, suggesting that the immune response to CT45 may be suppressed. In conclusion, classical Hodgkin lymphoma has the highest frequency of CT45 expression among all malignancies tested to date, the frequency of CT45 expression in DLBCL is similar to that seen in epithelial cancers, and low-grade non-Hodgkin B-cell lymphomas do not express CT45.

  5. Demons deformable registration of CT and cone-beam CT using an iterative intensity matching approach

    SciTech Connect

    Nithiananthan, Sajendra; Schafer, Sebastian; Uneri, Ali; and others

    2011-04-15

    Purpose: A method of intensity-based deformable registration of CT and cone-beam CT (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative registration process. The method preserves the speed and simplicity of the popular Demons algorithm while providing robustness and accuracy in the presence of large mismatch between CT and CBCT voxel values (''intensity''). Methods: A variant of the Demons algorithm was developed in which an estimate of the relationship between CT and CBCT intensity values for specific materials in the image is computed at each iteration based on the set of currently overlapping voxels. This tissue-specific intensity correction is then used to estimate the registration output for that iteration and the process is repeated. The robustness of the method was tested in CBCT images of a cadaveric head exhibiting a broad range of simulated intensity variations associated with x-ray scatter, object truncation, and/or errors in the reconstruction algorithm. The accuracy of CT-CBCT registration was also measured in six real cases, exhibiting deformations ranging from simple to complex during surgery or radiotherapy guided by a CBCT-capable C-arm or linear accelerator, respectively. Results: The iterative intensity matching approach was robust against all levels of intensity variation examined, including spatially varying errors in voxel value of a factor of 2 or more, as can be encountered in cases of high x-ray scatter. Registration accuracy without intensity matching degraded severely with increasing magnitude of intensity error and introduced image distortion. A single histogram match performed prior to registration alleviated some of these effects but was also prone to image distortion and was quantifiably less robust and accurate than the iterative approach. Within the six case registration accuracy study, iterative intensity matching Demons reduced mean TRE to (2.5{+-}2.8) mm compared to (3.5{+-}3.0) mm

  6. Dependence Of The Computerized Tomography (CT) Number - Electron Density Relationship On Patient Size And X-Ray Beam Filtration For Fan Beam CT Scanners

    NASA Astrophysics Data System (ADS)

    Masterson, M. E.; Thomason, C. L.; McGary, R.; Hunt, M. A.; Simpson, L. D.; Miller, D. W.; Laughlin, J. S.

    1981-07-01

    The applicability of quantitative information contained in CT scans to diagnostic radiology and to radiation therapy treatment planning and the heterogeneity problem has been recognized by members of the radiological community and by manufacturers. Determination of the relationship between electron density and CT number is important for these applications. As CT technology has evolved, CT number generation has changed. CT number variation was limited in the early water bag systems. However, later generation "air" scanners may exhibit variation in CT numbers across a reconstructed image which are re-lated to positioning within the scan circle and scan field size. Results of experimental investigations using tissue-equivalent phantoms of different cross-sectional shapes and areas on the Technicare Delta 2020 are presented. Investigations also cover the effect of "shaped" and "flat" x-ray beam filters. A variation in CT number is demonstrated on this fan beam geometry scanner for phantoms of different sizes and for different scan circle diameters. An explanation of these effects is given. Differences of as much as 20% in determination of tissue electron density relative to water under different experimental conditions are obtained and reported. A family of curves (electron density vs. CT number) is presented for different patient cross-sectional areas and different scanner settings.

  7. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities.

    PubMed

    Lechuga, Lawrence; Weidlich, Georg A

    2016-09-12

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities-fan beam and cone beam-was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient.

  8. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities

    PubMed Central

    Weidlich, Georg A.

    2016-01-01

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities—fan beam and cone beam—was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient. PMID:27752404

  9. TU-D-BRB-03: Dual-Energy CT: Considerations in Radiation Therapy.

    PubMed

    Coolens, C

    2016-06-01

    Dual-energy CT technology is becoming increasingly available to the medical imaging community. In addition, several models of CT simulators sold for use in radiation therapy departments now feature dual-energy technology. The images provided by dual-energy CT scanners add new information to the radiation treatment planning process; multiple spectral components can be used to separate and identify material composition as well as generate virtual monoenergetic images. In turn, this information could be used to investigate pathologic processes, separate the properties of contrast agents from soft tissues, assess tissue response to therapy, and other applications of therapeutic interest. Additionally, the decomposition of materials in images could directly integrate with and impact the accuracy of dose calculation algorithms. This symposium will explore methods of generating dual-energy CT images, spectral and image analysis algorithms, current and future applications of interest in oncologic imaging, and unique considerations when using dualenergy CT images in the radiation treatment planning process.

  10. TU-D-BRB-01: Dual-Energy CT: Techniques in Acquisition and Image Processing.

    PubMed

    Pelc, N

    2016-06-01

    Dual-energy CT technology is becoming increasingly available to the medical imaging community. In addition, several models of CT simulators sold for use in radiation therapy departments now feature dual-energy technology. The images provided by dual-energy CT scanners add new information to the radiation treatment planning process; multiple spectral components can be used to separate and identify material composition as well as generate virtual monoenergetic images. In turn, this information could be used to investigate pathologic processes, separate the properties of contrast agents from soft tissues, assess tissue response to therapy, and other applications of therapeutic interest. Additionally, the decomposition of materials in images could directly integrate with and impact the accuracy of dose calculation algorithms. This symposium will explore methods of generating dual-energy CT images, spectral and image analysis algorithms, current and future applications of interest in oncologic imaging, and unique considerations when using dualenergy CT images in the radiation treatment planning process.

  11. TU-D-BRB-02: Dual-Energy CT: Applications in Oncologic Imaging.

    PubMed

    Schoepf, U

    2016-06-01

    Dual-energy CT technology is becoming increasingly available to the medical imaging community. In addition, several models of CT simulators sold for use in radiation therapy departments now feature dual-energy technology. The images provided by dual-energy CT scanners add new information to the radiation treatment planning process; multiple spectral components can be used to separate and identify material composition as well as generate virtual monoenergetic images. In turn, this information could be used to investigate pathologic processes, separate the properties of contrast agents from soft tissues, assess tissue response to therapy, and other applications of therapeutic interest. Additionally, the decomposition of materials in images could directly integrate with and impact the accuracy of dose calculation algorithms. This symposium will explore methods of generating dual-energy CT images, spectral and image analysis algorithms, current and future applications of interest in oncologic imaging, and unique considerations when using dualenergy CT images in the radiation treatment planning process.

  12. The cavitation threshold of human tissue exposed to 0.2-MHz pulsed ultrasound: preliminary measurements based on a study of clinical lithotripsy.

    PubMed

    Coleman, A J; Kodama, T; Choi, M J; Adams, T; Saunders, J E

    1995-01-01

    Evidence of acoustic cavitation was identified in the form of transient echoes in ultrasound B-scan images of patients receiving extracorporeal shock-wave lithotripsy treatment on a Storz Modulith SL20. This lithotripter generates 10-microseconds duration pulses with a centre frequency of 0.2 MHz at a pulse repetition frequency of 1 Hz. The visual appearance of B-scan images was examined in a total of 30 patients and a quantitative analysis of echogenicity changes was carried out in six cases involving lithotripsy treatment of stones in the renal pelvis. In these patients new echoes were identified in images unaffected by movement artefacts and were found to occur in perinephric fat and adjacent muscle and kidney tissue at positions close to the axis of the shock-wave field between 1 and 2 cm in advance of the indicated beam focus of the lithotripter. The echogenicity within each region increased significantly above the background level when the output of the lithotripter was increased above a threshold value. The acoustic pressures corresponding to this threshold were measured in water using a calibrated PVDF membrane hydrophone. After correction for attenuation in tissue the cavitation thresholds, in terms of the temporal peak negative pressure, are found to lie between 1.5 MPa and 3.5 MPa in all six cases. Interpretation of the measured values in terms of the likely threshold at the higher frequencies used in diagnostic ultrasound is considered using a theoretical model.

  13. Transcriptional down-regulation of Brca1 and E-cadherin by CtBP1 in breast cancer.

    PubMed

    Deng, Yu; Deng, Hui; Liu, Jing; Han, Gangwen; Malkoski, Stephen; Liu, Bolin; Zhao, Rui; Wang, Xiao-Jing; Zhang, Qinghong

    2012-06-01

    Carboxyl-terminal binding protein 1 (CtBP1) is a transcriptional co-repressor with oncogenic potential. Immunohistochemistry staining using human breast cancer tissue arrays revealed that 92% of invasive ductal breast cancer cases have CtBP1-positive staining compared to 4% CtBP1-positive in normal breast tissue. To explore the functional impact of CtBP1 in breast cancer, we examined CtBP1's transcriptional regulation of known tumor suppressors, breast cancer susceptibility gene 1 (Brca1), and E-cadherin. We found CtBP1 was recruited to the promoter regions of Brca1 and E-cadherin genes in breast cancer cells. Concomitantly, Brca1 loss was detected in 57% and E-cadherin loss was detected in 76% of human invasive ductal breast cancers, and correlated with CtBP1 nuclear staining in these lesions. Importantly, siRNA knock down of CtBP1 restored Brca1 and E-cadherin expression in breast cancer cell lines, implying CtBP1 down-regulates Brca1 and E-cadherin genes in human breast cancer. This study provides evidence that although genetic loss of Brca1 and E-cadherin are infrequent in breast cancer, they are down-regulated at the transcriptional level by CtBP1 expression. Thus, CtBP1 activation could be a potential biomarker for breast cancer development.

  14. A minimum spanning forest based classification method for dedicated breast CT images

    SciTech Connect

    Pike, Robert; Sechopoulos, Ioannis; Fei, Baowei

    2015-11-15

    Purpose: To develop and test an automated algorithm to classify different types of tissue in dedicated breast CT images. Methods: Images of a single breast of five different patients were acquired with a dedicated breast CT clinical prototype. The breast CT images were processed by a multiscale bilateral filter to reduce noise while keeping edge information and were corrected to overcome cupping artifacts. As skin and glandular tissue have similar CT values on breast CT images, morphologic processing is used to identify the skin based on its position information. A support vector machine (SVM) is trained and the resulting model used to create a pixelwise classification map of fat and glandular tissue. By combining the results of the skin mask with the SVM results, the breast tissue is classified as skin, fat, and glandular tissue. This map is then used to identify markers for a minimum spanning forest that is grown to segment the image using spatial and intensity information. To evaluate the authors’ classification method, they use DICE overlap ratios to compare the results of the automated classification to those obtained by manual segmentation on five patient images. Results: Comparison between the automatic and the manual segmentation shows that the minimum spanning forest based classification method was able to successfully classify dedicated breast CT image with average DICE ratios of 96.9%, 89.8%, and 89.5% for fat, glandular, and skin tissue, respectively. Conclusions: A 2D minimum spanning forest based classification method was proposed and evaluated for classifying the fat, skin, and glandular tissue in dedicated breast CT images. The classification method can be used for dense breast tissue quantification, radiation dose assessment, and other applications in breast imaging.

  15. Thoracic textilomas: CT findings*

    PubMed Central

    Machado, Dianne Melo; Zanetti, Gláucia; Araujo, Cesar Augusto; Nobre, Luiz Felipe; Meirelles, Gustavo de Souza Portes; Pereira e Silva, Jorge Luiz; Guimarães, Marcos Duarte; Escuissato, Dante Luiz; Souza, Arthur Soares; Hochhegger, Bruno; Marchiori, Edson

    2014-01-01

    OBJECTIVE: The aim of this study was to analyze chest CT scans of patients with thoracic textiloma. METHODS: This was a retrospective study of 16 patients (11 men and 5 women) with surgically confirmed thoracic textiloma. The chest CT scans of those patients were evaluated by two independent observers, and discordant results were resolved by consensus. RESULTS: The majority (62.5%) of the textilomas were caused by previous heart surgery. The most common symptoms were chest pain (in 68.75%) and cough (in 56.25%). In all cases, the main tomographic finding was a mass with regular contours and borders that were well-defined or partially defined. Half of the textilomas occurred in the right hemithorax and half occurred in the left. The majority (56.25%) were located in the lower third of the lung. The diameter of the mass was ≤ 10 cm in 10 cases (62.5%) and > 10 cm in the remaining 6 cases (37.5%). Most (81.25%) of the textilomas were heterogeneous in density, with signs of calcification, gas, radiopaque marker, or sponge-like material. Peripheral expansion of the mass was observed in 12 (92.3%) of the 13 patients in whom a contrast agent was used. Intraoperatively, pleural involvement was observed in 14 cases (87.5%) and pericardial involvement was observed in 2 (12.5%). CONCLUSIONS: It is important to recognize the main tomographic aspects of thoracic textilomas in order to include this possibility in the differential diagnosis of chest pain and cough in patients with a history of heart or thoracic surgery, thus promoting the early identification and treatment of this postoperative complication. PMID:25410842

  16. WE-D-9A-02: Automated Landmark-Guided CT to Cone-Beam CT Deformable Image Registration

    SciTech Connect

    Kearney, V; Gu, X; Chen, S; Jiang, L; Liu, H; Chiu, T; Yordy, J; Nedzi, L; Mao, W

    2014-06-15

    Purpose: The anatomical changes that occur between the simulation CT and daily cone-beam CT (CBCT) are investigated using an automated landmark-guided deformable image registration (LDIR) algorithm with simultaneous intensity correction. LDIR was designed to be accurate in the presence of tissue intensity mismatch and heavy noise contamination. Method: An auto-landmark generation algorithm was used in conjunction with a local small volume (LSV) gradient matching search engine to map corresponding landmarks between the CBCT and planning CT. The LSVs offsets were used to perform an initial deformation, generate landmarks, and correct local intensity mismatch. The landmarks act as stabilizing controlpoints in the Demons objective function. The accuracy of the LDIR algorithm was evaluated on one synthetic case with ground truth and data of ten head and neck cancer patients. The deformation vector field (DVF) accuracy was accessed using a synthetic case. The Root mean square error of the 3D canny edge (RMSECE), mutual information (MI), and feature similarity index metric (FSIM) were used to access the accuracy of LDIR on the patient data. The quality of the corresponding deformed contours was verified by an attending physician. Results: The resulting 90 percentile DVF error for the synthetic case was within 5.63mm for the original demons algorithm, 2.84mm for intensity correction alone, 2.45mm using controlpoints without intensity correction, and 1.48 mm for the LDIR algorithm. For the five patients the mean RMSECE of the original CT, Demons deformed CT, intensity corrected Demons CT, control-point stabilized deformed CT, and LDIR CT was 0.24, 0.26, 0.20, 0.20, and 0.16 respectively. Conclusion: LDIR is accurate in the presence of multimodal intensity mismatch and CBCT noise contamination. Since LDIR is GPU based it can be implemented with minimal additional strain on clinical resources. This project has been supported by a CPRIT individual investigator award RP11032.

  17. PET/CT (and CT) instrumentation, image reconstruction and data transfer for radiotherapy planning.

    PubMed

    Sattler, Bernhard; Lee, John A; Lonsdale, Markus; Coche, Emmanuel

    2010-09-01

    The positron emission tomography in combination with CT in hybrid, cross-modality imaging systems (PET/CT) gains more and more importance as a part of the treatment-planning procedure in radiotherapy. Positron emission tomography (PET), as a integral part of nuclear medicine imaging and non-invasive imaging technique, offers the visualization and quantification of pre-selected tracer metabolism. In combination with the structural information from CT, this molecular imaging technique has great potential to support and improve the outcome of the treatment-planning procedure prior to radiotherapy. By the choice of the PET-Tracer, a variety of different metabolic processes can be visualized. First and foremost, this is the glucose metabolism of a tissue as well as for instance hypoxia or cell proliferation. This paper comprises the system characteristics of hybrid PET/CT systems. Acquisition and processing protocols are described in general and modifications to cope with the special needs in radiooncology. This starts with the different position of the patient on a special table top, continues with the use of the same fixation material as used for positioning of the patient in radiooncology while simulation and irradiation and leads to special processing protocols that include the delineation of the volumes that are subject to treatment planning and irradiation (PTV, GTV, CTV, etc.). General CT acquisition and processing parameters as well as the use of contrast enhancement of the CT are described. The possible risks and pitfalls the investigator could face during the hybrid-imaging procedure are explained and listed. The interdisciplinary use of different imaging modalities implies a increase of the volume of data created. These data need to be stored and communicated fast, safe and correct. Therefore, the DICOM-Standard provides objects and classes for this purpose (DICOM RT). Furthermore, the standard DICOM objects and classes for nuclear medicine (NM, PT) and

  18. CT scanning of the breast using a conventional CT scanner.

    PubMed

    Doust, B D; Milbrath, J R; Doust, V L

    1981-09-01

    Using a conventional body CT scanner, computed tomography of the breast was performed on 32 patients known to have or suspected of having breast masses. Xeromammograms were available for comparison in all cases. All mass lesions were histologically proved. Seven patients were examined prone, 25 supine. The prone position yielded pictures that resembled craniocaudal mammograms. Breast asymmetry, skin thickening, stranding from a mass to the chest wall, calcification, and axillary lymphadenopathy could be demonstrated by means of CT. The portion of the breast adjacent to the chest wall was more readily examined by means of CT than by conventional mammography. Internal mammary nodes could not be demonstrated.

  19. Experimental assessment of CT-based thermometry during laser ablation of porcine pancreas

    NASA Astrophysics Data System (ADS)

    Schena, E.; Saccomandi, P.; Giurazza, F.; Caponero, M. A.; Mortato, L.; Di Matteo, F. M.; Panzera, F.; Del Vescovo, R.; Beomonte Zobel, B.; Silvestri, S.

    2013-08-01

    Laser interstitial thermotherapy (LITT) is employed to destroy tumors in organs, and its outcome strongly depends on the temperature distribution inside the treated tissue. The recent introduction of computed tomography (CT) scan thermometry, based on the CT number dependence of the tissue with temperature, overcomes the invasiveness of other techniques used to monitor temperature during LITT. The averaged CT number (ROI = 0.02 cm2) of an ex vivo swine pancreas is monitored during LITT (Nd:YAG laser power of 3 W, treatment time: 120 s) at different distances from the applicator (from 4 to 30 mm). The averaged CT number shows a clear decrease during treatment: it is highest at 4 mm from the applicator (mean variation in the whole treatment of -0.256 HU s-1) and negligible at 30 mm, since the highest temperature increase is present close to the applicator (i.e., 45 °C at 4 mm and 25 °C at 6 mm). To obtain the relationship between CT numbers and pancreas temperature, the reference temperature was measured by 12 fiber Bragg grating sensors. The CT number decreases as a function of temperature, showing a nonlinear trend with a mean thermal sensitivity of -0.50 HU °C-1. Results here reported are the first assessment of pancreatic CT number dependence on temperature, at the best of our knowledge. Findings can be useful to further investigate CT scan thermometry during LITT on the pancreas.

  20. MULTIMODALITY IMAGING: BEYOND PET/CT AND SPECT/CT

    PubMed Central

    Cherry, Simon R.

    2009-01-01

    Multimodality imaging with PET/CT and SPECT/CT has become commonplace in clinical practice and in preclinical and basic medical research. Do other combinations of imaging modalities have a similar potential to impact medical science and clinical medicine? The combination of PET or SPECT with MRI is an area of active research at the present time, while other, perhaps less obvious combinations, including CT/MR and PET/optical also are being studied. In addition to the integration of the instrumentation, there are parallel developments in synthesizing imaging agents that can be viewed by multiple imaging modalities. Is the fusion of PET and SPECT with CT the ultimate answer in multimodality imaging, or is it just the first example of a more general trend towards harnessing the complementary nature of the different modalities on integrated imaging platforms? PMID:19646559

  1. A quantitative comparison of micro-CT preparations in Dipteran flies

    PubMed Central

    Swart, Peter; Wicklein, Martina; Sykes, Dan; Ahmed, Farah; Krapp, Holger G.

    2016-01-01

    X-ray-based 3D-imaging techniques have gained fundamental significance in research areas ranging from taxonomy to bioengineering. There is demand for the characterisation of species-specific morphological adaptations, micro-CTCT) being the method of choice in small-scale animals. This has driven the development of suitable staining techniques to improve absorption-based tissue contrast. A quantitative account on the limits of current staining protocols for preparing μCT specimen, however, is still missing. Here we present a study that quantifies results obtained by combining a variety of different contrast agents and fixative treatments that provides general guidance for μCT applications, particularly suitable for insect species. Using a blowfly model system (Calliphora), we enhanced effective spatial resolution and, in particular, optimised tissue contrast enabling semi-automated segmentation of soft and hard tissue from μCT data. We introduce a novel probabilistic measure of the contrast between tissues: PTC. Our results show that a strong iodine solution provides the greatest overall increase in tissue contrast, however phosphotungstic acid offers better inter-tissue discriminability. We further show that using paraformaldehyde as a fixative as opposed to ethanol, slows down the uptake of a staining solution by approximately a factor of two. PMID:28000717

  2. Analysis of patient CT dose data using virtualdose

    NASA Astrophysics Data System (ADS)

    Bennett, Richard

    -Expo for organ dose difference versus age, male phantoms show percent difference of -19 % to 25 % for various organs minus bone surface and breast tissues results. Finally, for organ dose difference across all software for average adult phantom the results range from -45 % to 6 % in the comparison of ImPACT CT to VirtualDose and -27 % to 66 % for the comparison of CT-Expo to VirtualDose. In the comparison for increased BMI (done only in VirtualDose), results show that with all other parameters fixed, the organ dose goes down as BMI increases, which is due to the increase in adipose tissue and bulk of the patient model. The range of results when comparing all the three softwares have a wide range, in some cases greater than 150 %, it is evident that using a different anatomical basis for the human phantom and the theoretical basis for the dose estimation will cause fluctuation in the results. Therefore, choosing the software with the most accurate human phantom will provide a closer range to the true dose to the organ.

  3. Generation of synthetic CT data using patient specific daily MR image data and image registration

    NASA Astrophysics Data System (ADS)

    Melanie Kraus, Kim; Jäkel, Oliver; Niebuhr, Nina I.; Pfaffenberger, Asja

    2017-02-01

    To fully exploit the advantages of magnetic resonance imaging (MRI) for radiotherapy (RT) treatment planning, a method is required to overcome the problem of lacking electron density information. We aim to establish and evaluate a new method for computed tomography (CT) data generation based on MRI and image registration. The thereby generated CT data is used for dose accumulation. We developed a process flow based on an initial pair of rigidly co-registered CT and T2-weighted MR image representing the same anatomical situation. Deformable image registration using anatomical landmarks is performed between the initial MRI data and daily MR images. The resulting transformation is applied to the initial CT, thus fractional CT data is generated. Furthermore, the dose for a photon intensity modulated RT (IMRT) or intensity modulated proton therapy (IMPT) plan is calculated on the generated fractional CT and accumulated on the initial CT via inverse transformation. The method is evaluated by the use of phantom CT and MRI data. Quantitative validation is performed by evaluation of the mean absolute error (MAE) between the measured and the generated CT. The effect on dose accumulation is examined by means of dose-volume parameters. One patient case is presented to demonstrate the applicability of the method introduced here. Overall, CT data derivation lead to MAEs with a median of 37.0 HU ranging from 29.9 to 66.6 HU for all investigated tissues. The accuracy of image registration showed to be limited in the case of unexpected air cavities and at tissue boundaries. The comparisons of dose distributions based on measured and generated CT data agree well with the published literature. Differences in dose volume parameters kept within 1.6% and 3.2% for photon and proton RT, respectively. The method presented here is particularly suited for application in adaptive RT in current clinical routine, since only minor additional technical equipment is required.

  4. Investigation of pathogen infiltration into produce using Xradia Bio MicroCT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The internalization of human pathogens into plant tissues has received significant attention. Human pathogens can infiltrate plant tissue through stomata, cut edges, wounds on produce, or the plant vascular system. The nondestructive X-ray computed microtomography (MicroCT) technique is an X-ra...

  5. Automatic classification of lung tumour heterogeneity according to a visual-based score system in dynamic contrast enhanced CT sequences

    NASA Astrophysics Data System (ADS)

    Bevilacqua, Alessandro; Baiocco, Serena

    2016-03-01

    Computed tomography (CT) technologies have been considered for a long time as one of the most effective medical imaging tools for morphological analysis of body parts. Contrast Enhanced CT (CE-CT) also allows emphasising details of tissue structures whose heterogeneity, inspected through visual analysis, conveys crucial information regarding diagnosis and prognosis in several clinical pathologies. Recently, Dynamic CE-CT (DCE-CT) has emerged as a promising technique to perform also functional hemodynamic studies, with wide applications in the oncologic field. DCE-CT is based on repeated scans over time performed after intravenous administration of contrast agent, in order to study the temporal evolution of the tracer in 3D tumour tissue. DCE-CT pushes towards an intensive use of computers to provide automatically quantitative information to be used directly in clinical practice. This requires that visual analysis, representing the gold-standard for CT image interpretation, gains objectivity. This work presents the first automatic approach to quantify and classify the lung tumour heterogeneities based on DCE-CT image sequences, so as it is performed through visual analysis by experts. The approach developed relies on the spatio-temporal indices we devised, which also allow exploiting temporal data that enrich the knowledge of the tissue heterogeneity by providing information regarding the lesion status.

  6. Errors in CT colonography.

    PubMed

    Trilisky, Igor; Ward, Emily; Dachman, Abraham H

    2015-10-01

    CT colonography (CTC) is a colorectal cancer screening modality which is becoming more widely implemented and has shown polyp detection rates comparable to those of optical colonoscopy. CTC has the potential to improve population screening rates due to its minimal invasiveness, no sedation requirement, potential for reduced cathartic examination, faster patient throughput, and cost-effectiveness. Proper implementation of a CTC screening program requires careful attention to numerous factors, including patient preparation prior to the examination, the technical aspects of image acquisition, and post-processing of the acquired data. A CTC workstation with dedicated software is required with integrated CTC-specific display features. Many workstations include computer-aided detection software which is designed to decrease errors of detection by detecting and displaying polyp-candidates to the reader for evaluation. There are several pitfalls which may result in false-negative and false-positive reader interpretation. We present an overview of the potential errors in CTC and a systematic approach to avoid them.

  7. Multiscale registration of planning CT and daily cone beam CT images for adaptive radiation therapy

    SciTech Connect

    Paquin, Dana; Levy, Doron; Xing Lei

    2009-01-15

    Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation dose to the tumor while minimizing the amount of radiation delivered to healthy tissue. Registration of planning images with daily images is thus an important component of ART. In this article, the authors report their research on multiscale registration of planning computed tomography (CT) images with daily cone beam CT (CBCT) images. The multiscale algorithm is based on the hierarchical multiscale image decomposition of E. Tadmor, S. Nezzar, and L. Vese [Multiscale Model. Simul. 2(4), pp. 554-579 (2004)]. Registration is achieved by decomposing the images to be registered into a series of scales using the (BV, L{sup 2}) decomposition and initially registering the coarsest scales of the image using a landmark-based registration algorithm. The resulting transformation is then used as a starting point to deformably register the next coarse scales with one another. This procedure is iterated at each stage using the transformation computed by the previous scale registration as the starting point for the current registration. The authors present the results of studies of rectum, head-neck, and prostate CT-CBCT registration, and validate their registration method quantitatively using synthetic results in which the exact transformations our known, and qualitatively using clinical deformations in which the exact results are not known.

  8. Automatic nonrigid registration of whole body CT mice images.

    PubMed

    Li, Xia; Yankeelov, Thomas E; Peterson, Todd E; Gore, John C; Dawant, Benoit M

    2008-04-01

    Three-dimensional intra- and intersubject registration of image volumes is important for tasks that include quantification of temporal/longitudinal changes, atlas-based segmentation, computing population averages, or voxel and tensor-based morphometry. While a number of methods have been proposed to address this problem, few have focused on the problem of registering whole body image volumes acquired either from humans or small animals. These image volumes typically contain a large number of articulated structures, which makes registration more difficult than the registration of head images, to which the majority of registration algorithms have been applied. This article presents a new method for the automatic registration of whole body computed tomography (CT) volumes, which consists of two main steps. Skeletons are first brought into approximate correspondence with a robust point-based method. Transformations so obtained are refined with an intensity-based nonrigid registration algorithm that includes spatial adaptation of the transformation's stiffness. The approach has been applied to whole body CT images of mice, to CT images of the human upper torso, and to human head and neck CT images. To validate the authors method on soft tissue structures, which are difficult to see in CT images, the authors use coregistered magnetic resonance images. They demonstrate that the approach they propose can successfully register image volumes even when these volumes are very different in size and shape or if they have been acquired with the subjects in different positions.

  9. Image analysis of pulmonary nodules using micro CT

    NASA Astrophysics Data System (ADS)

    Niki, Noboru; Kawata, Yoshiki; Fujii, Masashi; Kakinuma, Ryutaro; Moriyama, Noriyuki; Tateno, Yukio; Matsui, Eisuke

    2001-07-01

    We are developing a micro-computed tomography (micro CT) system for imaging pulmonary nodules. The purpose is to enhance the physician performance in accessing the micro- architecture of the nodule for classification between malignant and benign nodules. The basic components of the micro CT system consist of microfocus X-ray source, a specimen manipulator, and an image intensifier detector coupled to charge-coupled device (CCD) camera. 3D image reconstruction was performed by the slice. A standard fan- beam convolution and backprojection algorithm was used to reconstruct the center plane intersecting the X-ray source. The preprocessing of the 3D image reconstruction included the correction of the geometrical distortions and the shading artifact introduced by the image intensifier. The main advantage of the system is to obtain a high spatial resolution which ranges between b micrometers and 25 micrometers . In this work we report on preliminary studies performed with the micro CT for imaging resected tissues of normal and abnormal lung. Experimental results reveal micro architecture of lung tissues, such as alveolar wall, septal wall of pulmonary lobule, and bronchiole. From the results, the micro CT system is expected to have interesting potentials for high confidential differential diagnosis.

  10. Dynamic CT head phantom for perfusion and angiography studies

    NASA Astrophysics Data System (ADS)

    Russell, K.; Blazeski, A.; Dannecker, K.; Lee, Q. Y.; Holscher, C.; Donahue, C.; van Kampen, W.

    2010-03-01

    Contrast imaging is a compelling enhancement for the portable, flat panel-based brain CT scanner currently under development at Xoran. Due to the relative low temporal resolution of flat panel detectors, enabling tomographic imaging on such platform requires optimizing the imaging and injection protocols. A dynamic CT head phantom was designed to facilitate this task. The Dynamic Perfusion and Angiography Model (PAM), mimics tissue attenuation in CT images, provides physiological timing for angiography and perfusion studies, and moves fluid with properties similar to those of blood. The design consists of an arterial system, which contains bifurcating vessels that feed into perfusion chambers, mimicking blood flow through capillaries and smaller vessels, and a venous system, which is symmetrical to the arterial side and drains the perfusion chambers. The variation of geometry and flow rate in the phantom provides the physiological total time that fluid spends in the head, and the difference in material densities correlates to CT numbers for biological tissues. This paper discusses the design of Dynamic PAM and shows experimental results demonstrating its ability to realistically simulate blood flow. Results of dynamic imaging studies of the phantom are also presented.

  11. In vivo small animal micro-CT using nanoparticle contrast agents.

    PubMed

    Ashton, Jeffrey R; West, Jennifer L; Badea, Cristian T

    2015-01-01

    Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research.

  12. In vivo small animal micro-CT using nanoparticle contrast agents

    PubMed Central

    Ashton, Jeffrey R.; West, Jennifer L.; Badea, Cristian T.

    2015-01-01

    Computed tomography (CT) is one of the most valuable modalities for in vivo imaging because it is fast, high-resolution, cost-effective, and non-invasive. Moreover, CT is heavily used not only in the clinic (for both diagnostics and treatment planning) but also in preclinical research as micro-CT. Although CT is inherently effective for lung and bone imaging, soft tissue imaging requires the use of contrast agents. For small animal micro-CT, nanoparticle contrast agents are used in order to avoid rapid renal clearance. A variety of nanoparticles have been used for micro-CT imaging, but the majority of research has focused on the use of iodine-containing nanoparticles and gold nanoparticles. Both nanoparticle types can act as highly effective blood pool contrast agents or can be targeted using a wide variety of targeting mechanisms. CT imaging can be further enhanced by adding spectral capabilities to separate multiple co-injected nanoparticles in vivo. Spectral CT, using both energy-integrating and energy-resolving detectors, has been used with multiple contrast agents to enable functional and molecular imaging. This review focuses on new developments for in vivo small animal micro-CT using novel nanoparticle probes applied in preclinical research. PMID:26581654

  13. Greening America's Capitals - Hartford, CT

    EPA Pesticide Factsheets

    This Greening America's Capitals report gives Hartford, CT, a new vision for Capitol Avenue that highlights existing assets and fills in gaps along the mile-long area of focus and into the surrounding neighborhoods.

  14. Multiplanar CT of the spine

    SciTech Connect

    Rothman, S.L.G.; Glenn, W.V. Jr.

    1986-01-01

    This is an illustrated text on computed tomography (CT) of the lumbar spine with an emphasis on the role and value of multiplanar imaging for helping determine diagnoses. The book has adequate discussion of scanning techniques for the different regions, interpretations of various abnormalities, degenerative disk disease, and different diagnoses. There is a 50-page chapter on detailed sectional anatomy of the spine and useful chapters on the postoperative spine and the planning and performing of spinal surgery with CT multiplanar reconstruction. There are comprehensive chapters on spinal tumors and trauma. The final two chapters of the book are devoted to CT image processing using digital networks and CT applications of medical computer graphics.

  15. CT Perfusion of the Head

    MedlinePlus

    ... ray beam follows a spiral path. A special computer program processes this large volume of data to create ... process. Nearly all CT scanners now have special computer programs that help to increase image quality at lower ...

  16. CT Demonstration of Caput Medusae

    ERIC Educational Resources Information Center

    Weber, Edward C.; Vilensky, Joel A.

    2009-01-01

    Maximum intensity and volume rendered CT displays of caput medusae are provided to demonstrate both the anatomy and physiology of this portosystemic shunt associated with portal hypertension. (Contains 2 figures.)

  17. Adrenal cortex dysfunction: CT findings

    SciTech Connect

    Huebener, K.H.; Treugut, H.

    1984-01-01

    The computed tomographic appearance of the adrenal gland was studied in 302 patients with possible endocrinologic disease and 107 patients undergoing CT for nonendocrinologic reasons. Measurements of adrenal size were also made in 100 adults with no known adrenal pathology. CT proved to be a sensitive diagnostic tool in combination with clinical studies. When blood hormone levels are increased, CT can differentiate among homogeneous organic hyperplasia, nodular hyperplasia, benign adenoma, and malignant cortical adenoma. When blood hormone levels are decreased, CT can demonstrate hypoplasia or metastatic tumorous destruction. Calcifications can be demonstrated earlier than on plain radiographs. When hormone elimination is increased, the morphologic substrate can be identified; tumorous changes can be localized and infiltration of surrounding organs recognized.

  18. Children's (Pediatric) CT (Computed Tomography)

    MedlinePlus Videos and Cool Tools

    ... What are the limitations of Children's CT? A person who is very large may not fit into ... facility staff and/or your insurance provider to get a better understanding of the possible charges you ...

  19. CT angiography - head and neck

    MedlinePlus

    ... medlineplus.gov/ency/article/007677.htm CT angiography - head and neck To use the sharing features on this page, ... create pictures of the blood vessels in the head and neck. How the Test is Performed You will be ...

  20. Multiplanar CT of the spine

    SciTech Connect

    Rothman, S.L.G.; Glenn, W.V.

    1985-01-01

    This book contains 16 chapters. Some of the topics are: CT of the Sacrum, The Postoperative Spine, Film Organizations and Case Reporting, Degeneration and Disc Disease of the Intervertebral Joint, Lumbar Spinal Stenosis, and Cervical and Thoracic Spine.

  1. A tonsillolith seen on CT.

    PubMed

    Espe, B J; Newmark, H

    1992-01-01

    A case of a large tonsillolith visualized by computerized tomography is presented. Although otolaryngologists are well aware of this entity, few radiologists are. The importance of distinguishing tonsilloliths from other structures by CT scan is discussed.

  2. Liver echinococcus - CT scan (image)

    MedlinePlus

    This upper abdominal CT scan shows multiple cysts in the liver, caused by dog tapeworm (echinococcus). Note the large circular cyst (seen on the left side of the screen) and multiple smaller cysts throughout ...

  3. Primary lower extremity lymphedema: CT diagnosis

    SciTech Connect

    Gamba, J.L.; Silverman, P.M.; Ling, D.; Dunnick, N.R.; Korobkin, M.

    1983-10-01

    The CT findings of two cases of primary lymphedema of the lower extremities are presented. CT showed a coarse, nonenhancing, reticular pattern in an enlarged subcutaneous compartment. CT excluded the diagnosis of secondary lymphedema from an obstructing mass by demonstrating a normal retroperitoneum and pelvis. The CT findings are correlated with pedal lymphangiograms.

  4. DNA hypomethylation-mediated activation of Cancer/Testis Antigen 45 (CT45) genes is associated with disease progression and reduced survival in epithelial ovarian cancer.

    PubMed

    Zhang, Wa; Barger, Carter J; Link, Petra A; Mhawech-Fauceglia, Paulette; Miller, Austin; Akers, Stacey N; Odunsi, Kunle; Karpf, Adam R

    2015-01-01

    Epithelial ovarian cancer (EOC) is a highly lethal malignancy due to a lack of early detection approaches coupled with poor outcomes for patients with clinically advanced disease. Cancer-testis (CT) or cancer-germline genes encode antigens known to generate spontaneous anti-tumor immunity in cancer patients. CT45 genes are a recently discovered 6-member family of X-linked CT genes with oncogenic function. Here, we determined CT45 expression in EOC and fully defined its epigenetic regulation by DNA methylation. CT45 was silent and hypermethylated in normal control tissues, but a large subset of EOC samples showed increased CT45 expression in conjunction with promoter DNA hypomethylation. In contrast, copy number status did not correlate with CT45 expression in the TCGA database for EOC. CT45 promoter methylation inversely correlated with both CT45 mRNA and protein expression, the latter determined using IHC staining of an EOC TMA. CT45 expression was increased and CT45 promoter methylation was decreased in late-stage and high-grade EOC, and both measures were associated with poor survival. CT45 hypomethylation was directly associated with LINE-1 hypomethylation, and CT45 was frequently co-expressed with other CT antigen genes in EOC. Decitabine treatment induced CT45 mRNA and protein expression in EOC cells, and promoter transgene analyses indicated that DNA methylation directly represses CT45 promoter activity. These data verify CT45 expression and promoter hypomethylation as possible prognostic biomarkers, and suggest CT45 as an immunological or therapeutic target in EOC. Treatment with decitabine or other epigenetic modulators could provide a means for more effective immunological targeting of CT45.

  5. DNA hypomethylation-mediated activation of Cancer/Testis Antigen 45 (CT45) genes is associated with disease progression and reduced survival in epithelial ovarian cancer

    PubMed Central

    Zhang, Wa; Barger, Carter J; Link, Petra A; Mhawech-Fauceglia, Paulette; Miller, Austin; Akers, Stacey N; Odunsi, Kunle; Karpf, Adam R

    2015-01-01

    Epithelial ovarian cancer (EOC) is a highly lethal malignancy due to a lack of early detection approaches coupled with poor outcomes for patients with clinically advanced disease. Cancer-testis (CT) or cancer-germline genes encode antigens known to generate spontaneous anti-tumor immunity in cancer patients. CT45 genes are a recently discovered 6-member family of X-linked CT genes with oncogenic function. Here, we determined CT45 expression in EOC and fully defined its epigenetic regulation by DNA methylation. CT45 was silent and hypermethylated in normal control tissues, but a large subset of EOC samples showed increased CT45 expression in conjunction with promoter DNA hypomethylation. In contrast, copy number status did not correlate with CT45 expression in the TCGA database for EOC. CT45 promoter methylation inversely correlated with both CT45 mRNA and protein expression, the latter determined using IHC staining of an EOC TMA. CT45 expression was increased and CT45 promoter methylation was decreased in late-stage and high-grade EOC, and both measures were associated with poor survival. CT45 hypomethylation was directly associated with LINE-1 hypomethylation, and CT45 was frequently co-expressed with other CT antigen genes in EOC. Decitabine treatment induced CT45 mRNA and protein expression in EOC cells, and promoter transgene analyses indicated that DNA methylation directly represses CT45 promoter activity. These data verify CT45 expression and promoter hypomethylation as possible prognostic biomarkers, and suggest CT45 as an immunological or therapeutic target in EOC. Treatment with decitabine or other epigenetic modulators could provide a means for more effective immunological targeting of CT45. PMID:26098711

  6. Accuracy of CT-based attenuation correction in PET/CT bone imaging.

    PubMed

    Abella, Monica; Alessio, Adam M; Mankoff, David A; MacDonald, Lawrence R; Vaquero, Juan Jose; Desco, Manuel; Kinahan, Paul E

    2012-05-07

    We evaluate the accuracy of scaling CT images for attenuation correction of PET data measured for bone. While the standard tri-linear approach has been well tested for soft tissues, the impact of CT-based attenuation correction on the accuracy of tracer uptake in bone has not been reported in detail. We measured the accuracy of attenuation coefficients of bovine femur segments and patient data using a tri-linear method applied to CT images obtained at different kVp settings. Attenuation values at 511 keV obtained with a (68)Ga/(68)Ge transmission scan were used as a reference standard. The impact of inaccurate attenuation images on PET standardized uptake values (SUVs) was then evaluated using simulated emission images and emission images from five patients with elevated levels of FDG uptake in bone at disease sites. The CT-based linear attenuation images of the bovine femur segments underestimated the true values by 2.9 ± 0.3% for cancellous bone regardless of kVp. For compact bone the underestimation ranged from 1.3% at 140 kVp to 14.1% at 80 kVp. In the patient scans at 140 kVp the underestimation was approximately 2% averaged over all bony regions. The sensitivity analysis indicated that errors in PET SUVs in bone are approximately proportional to errors in the estimated attenuation coefficients for the same regions. The variability in SUV bias also increased approximately linearly with the error in linear attenuation coefficients. These results suggest that bias in bone uptake SUVs of PET tracers ranges from 2.4% to 5.9% when using CT scans at 140 and 120 kVp for attenuation correction. Lower kVp scans have the potential for considerably more error in dense bone. This bias is present in any PET tracer with bone uptake but may be clinically insignificant for many imaging tasks. However, errors from CT-based attenuation correction methods should be carefully evaluated if quantitation of tracer uptake in bone is important.

  7. Accuracy of CT-Based Attenuation Correction in PET/CT Bone Imaging

    PubMed Central

    Abella, Monica; Alessio, Adam M.; Mankoff, David A.; MacDonald, Lawrence R.; Vaquero, Juan Jose; Desco, Manuel; Kinahan, Paul E.

    2012-01-01

    We evaluate the accuracy of scaling CT images for attenuation correction of PET data measured for bone. While the standard tri-linear approach has been well-tested for soft tissues, the impact of CT-based attenuation correction on the accuracy of tracer uptake in bone has not been reported in detail. We measured the accuracy of attenuation coefficients of bovine femur segments and patient data using a tri-linear method applied to CT images obtained at different kVp settings. Attenuation values at 511 keV obtained with a 68Ga/68Ge transmission scan were used as a reference standard. The impact of inaccurate attenuation images on PET standardized uptake values (SUVs) was then evaluated using simulated emission images and emission images from five patients with elevated levels of FDG uptake in bone at disease sites. The CT-based linear attenuation images of the bovine femur segments underestimated the true values by 2.9±0.3% for cancellous bone regardless of kVp. For compact bone the underestimation ranged from 1.3% at 140 kVp to 14.1% at 80 kVp. In the patient scans at 140 kVp the underestimation was approximately 2% averaged over all bony regions. The sensitivity analysis indicated that errors in PET SUVs in bone are approximately proportional to errors in the estimated attenuation coefficients for the same regions. The variability in SUV bias also increased approximately linearly with the error in linear attenuation coefficients. These results suggest that bias in bone uptake SUVs of PET tracers range from 2.4% to 5.9% when using CT scans at 140 and 120 kVp for attenuation correction. Lower kVp scans have the potential for considerably more error in dense bone. This bias is present in any PET tracer with bone uptake but may be clinically insignificant for many imaging tasks. However, errors from CT-based attenuation correction methods should be carefully evaluated if quantitation of tracer uptake in bone is important. PMID:22481547

  8. Musculoskeletal applications of flat-panel volume CT.

    PubMed

    Reichardt, Benjamin; Sarwar, Ammar; Bartling, Soenke H; Cheung, Arnold; Grasruck, Michael; Leidecker, Christianne; Bredella, Miriam A; Brady, Thomas J; Gupta, Rajiv

    2008-12-01

    Flat-panel volume computed tomography (fpVCT) is a recent development in imaging. We discuss some of the musculoskeletal applications of a high-resolution flat-panel CT scanner. FpVCT has four main advantages over conventional multidetector computed tomography (MDCT): high-resolution imaging; volumetric coverage; dynamic imaging; omni-scanning. The overall effective dose of fpVCT is comparable to that of MDCT scanning. Although current fpVCT technology has higher spatial resolution, its contrast resolution is slightly lower than that of MDCT (5-10HU vs. 1-3HU respectively). We discuss the efficacy and potential utility of fpVCT in various applications related to musculoskeletal radiology and review some novel applications for pediatric bones, soft tissues, tumor perfusion, and imaging of tissue-engineered bone growth. We further discuss high-resolution CT and omni-scanning (combines fluoroscopic and tomographic imaging).

  9. Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction

    SciTech Connect

    Brady, Samuel L.; Shulkin, Barry L.

    2015-02-15

    Purpose: To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (10–35 mA s). CT quantitation: noise, low-contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUV{sub bw}) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative dose reduction and noise control. Results: CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUV{sub bw}, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.3–0.9/6.2). Noise magnitude in dose-reduced patient images increased but was not statistically different from predose-reduced patient images. Conclusions: Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake.

  10. Periosteal ganglia: CT and MR imaging features.

    PubMed

    Abdelwahab, I F; Kenan, S; Hermann, G; Klein, M J; Lewis, M M

    1993-07-01

    The imaging features of four cases of periosteal ganglia were studied. Three lesions were located over the proximal shaft of the tibia, in proximity to the pes anserinus. The fourth lesion involved the distal shaft of the ulna. Three lesions had different degrees of external cortical erosion, scalloping, and thick spicules of periosteal bone on plain radiographs. The bone adjacent to the fourth lesion was not involved. Computed tomography (CT) showed these lesions to be sharply defined soft-tissue masses abutting the periosteum. All of the lesions had the same attenuation as fluid. Magnetic resonance (MR) imaging revealed the ganglia to be sharply defined masses that were isointense compared with neighboring muscles on T1-weighted images. There was markedly increased signal intensity compared with that of fat on T2-weighted images. The signal intensity on both types of images was homogeneous. The MR imaging features were consistent with the fluid nature of the lesions. Under the appropriate clinical circumstances, the MR imaging and CT features of periosteal ganglia are diagnostic.

  11. Mass preserving registration for lung CT

    NASA Astrophysics Data System (ADS)

    Gorbunova, Vladlena; Lo, Pechin; Loeve, Martine; Tiddens, Harm A.; Sporring, Jon; Nielsen, Mads; de Bruijne, Marleen

    2009-02-01

    In this paper, we evaluate a novel image registration method on a set of expiratory-inspiratory pairs of computed tomography (CT) lung scans. A free-form multi resolution image registration technique is used to match two scans of the same subject. To account for the differences in the lung intensities due to differences in inspiration level, we propose to adjust the intensity of lung tissue according to the local expansion or compression. An image registration method without intensity adjustment is compared to the proposed method. Both approaches are evaluated on a set of 10 pairs of expiration and inspiration CT scans of children with cystic fibrosis lung disease. The proposed method with mass preserving adjustment results in significantly better alignment of the vessel trees. Analysis of local volume change for regions with trapped air compared to normally ventilated regions revealed larger differences between these regions in the case of mass preserving image registration, indicating that mass preserving registration is better at capturing localized differences in lung deformation.

  12. Tissue types (image)

    MedlinePlus

    There are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues). ...

  13. Dosimetric and workflow evaluation of first commercial synthetic CT software for clinical use in pelvis

    NASA Astrophysics Data System (ADS)

    Tyagi, Neelam; Fontenla, Sandra; Zhang, Jing; Cloutier, Michelle; Kadbi, Mo; Mechalakos, Jim; Zelefsky, Michael; Deasy, Joe; Hunt, Margie

    2017-04-01

    To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy. Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and a dual echo 3D mDIXON fast field echo (FFE) sequence for generating syn-CT. A dual-echo 3D FFE B 0 map was used for patient-induced susceptibility distortion analysis and a new 3D balanced-FFE sequence was evaluated for identification of implanted gold fiducial markers and subsequent image-guidance during radiotherapy delivery. Tissues were classified as air, adipose, water, trabecular/spongy bone and compact/cortical bone and assigned bulk HU values. The accuracy of syn-CT for treatment planning was analyzed by transferring the structures and plan from planning CT to syn-CT and recalculating the dose. Accuracy of localization at the treatment machine was evaluated by comparing registration of kV radiographs to either digitally reconstructed radiographs (DRRs) generated from syn-CT or traditional DRRs generated from the planning CT. Similarly, accuracy of setup using CBCT and syn-CT was compared to that using the planning CT. Finally, a MR-only simulation workflow was established and end-to-end testing was completed on five patients undergoing MR-only simulation. Dosimetric comparison between the original CT and syn-CT plans was within 0.5% on average for all structures. The de-novo optimized plans on the syn-CT met institutional clinical objectives for target and normal structures. Patient-induced susceptibility distortion based on B 0 maps was within 1 mm and 0.5 mm in the body and prostate respectively. DRR and CBCT localization based on MR-localized fiducials showed a standard deviation of  <1 mm. End-to-end testing and MR simulation workflow was successfully validated. MRI derived synthetic CT can be successfully used for a MR

  14. Construction and data analysis of the fiber tracker detector for pCT project

    NASA Astrophysics Data System (ADS)

    Zvoda, Viktoriya

    Proton radiation therapy is a fast growing form of cancer treatment; it requires a precise knowledge of the dose delivered to the tumor and verification of the correct patient position with respect to the proton beam to avoid damage to critical normal tissues and geographical tumor misses. In existing proton treatment centers dose calculations are performed based on conventional x-ray computed tomography (CT). The goal of the Proton Computed Tomography (pCT) project is provide a fully operational detecting system that allows imaging of the patient (or a phantom) directly with proton CT by measuring the energy loss and trajectories of high-energy protons that traverse the patient. The pCT detector contains the upstream tracking detectors, phantom, the downstream tracking detectors, and a calorimeter. The step-by-step assembly of the pCT NIU Phase 2 Scanner and the subsequent tests and calibration procedures are described in the current thesis.

  15. In-line phase contrast micro-CT reconstruction for biomedical specimens.

    PubMed

    Fu, Jian; Tan, Renbo

    2014-01-01

    X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology.

  16. Algorithm of pulmonary emphysema extraction using thoracic 3-D CT images

    NASA Astrophysics Data System (ADS)

    Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

    2008-03-01

    Emphysema patients have the tendency to increase due to aging and smoking. Emphysematous disease destroys alveolus and to repair is impossible, thus early detection is essential. CT value of lung tissue decreases due to the destruction of lung structure. This CT value becomes lower than the normal lung- low density absorption region or referred to as Low Attenuation Area (LAA). So far, the conventional way of extracting LAA by simple thresholding has been proposed. However, the CT value of CT image fluctuates due to the measurement conditions, with various bias components such as inspiration, expiration and congestion. It is therefore necessary to consider these bias components in the extraction of LAA. We removed these bias components and we proposed LAA extraction algorithm. This algorithm has been applied to the phantom image. Then, by using the low dose CT(normal: 30 cases, obstructive lung disease: 26 cases), we extracted early stage LAA and quantitatively analyzed lung lobes using lung structure.

  17. A preliminary study of CT imaging of water in a carnation flower

    NASA Astrophysics Data System (ADS)

    Nakanishi, T. M.; Furukawa, J.; Matsubayashi, M.

    1999-11-01

    We present the trial to determine the water deletion part in a carnation flower tissue while drying by neutron computer tomography (CT). The flower part was fixed on a rotating disk and thermal neutrons were irradiated for 4 s per projection. The total neutron dose was 6.0×10 8 n/cm 2 per projection. The neutrons penetrating the sample were converted to photons by a fluorescence converter. The photon image was guided to a cooled CCD camera using two mirrors. The sample was rotated, stepwise, every 1°, up to 180°, i.e. 180 images were obtained for the CT construction. Horizontal CT images of several slices of the flower were taken before and after the drying treatment. Vertical CT images of the flower were also constructed based on horizontal CT images. It was found that the water around the ovule was selectively removed by the drying treatment.

  18. Microstructure analysis of the pulmonary acinus using a synchrotron radiation CT

    NASA Astrophysics Data System (ADS)

    Tokumoto, Y.; Minami, K.; Kawata, Y.; Niki, N.; Umetani, K.; Nakano, Y.; Sakai, H.; Ohmatsu, H.; Itoh, H.

    2015-03-01

    Conversion of images at micro level of normal and with very early stage disease of the lung and quantitative analysis of morphology on CT image can contribute to the chest image diagnosis to the next generation. Previous, anatomy and pathology analysis of pulmonary lobule have been conducted to better understand the CT image of peripheral lung tissue disease. However, it is difficult to figure out three-dimensional (3D) conformation because of analyzing at the slice image. The purpose of this study is a 3D microstructual and quantitative analyses of pulmonary acinus with spatial resolution in the range of several micrometers by using a synchrotron radiation micro CT (SRμCT). In this paper, we present a semi-automatic method for segmenting the secondary pulmonary lobule into acinus or subacinus and extracting small vessel in human acinus imaged by the SRμCT.

  19. The impact of spectral filtration on image quality in micro-CT system.

    PubMed

    Ren, Liqiang; Ghani, Muhammad U; Wu, Di; Zheng, Bin; Chen, Yong; Yang, Kai; Wu, Xizeng; Liu, Hong

    2016-01-08

    This paper aims to evaluate the impact of spectral filtration on image quality in a microcomputed tomography (micro-CT) system. A mouse phantom comprising 11rods for modeling lung, muscle, adipose, and bones was scanned with 17 s and 2min, respectively. The current (μA) for each scan was adjusted to achieve identical entrance exposure to the phantom, providing a baseline for image quality evaluation. For each region of interest (ROI) within specific composition, CT number variations, noise levels, and contrast-to-noise ratios (CNRs) were evaluated from the reconstructed images. CT number variations and CNRs for bone with high density, muscle, and adipose were compared with theoretical predictions. The results show that the impact of spectral filtration on image quality indicators, such as CNR in a micro-CT system, is significantly associated with tissue characteristics. The findings may provide useful references for optimizing the scanning parameters of general micro-CT systems in future imaging applications.

  20. CT/FMT dual-model imaging of breast cancer based on peptide-lipid nanoparticles

    NASA Astrophysics Data System (ADS)

    Xu, Guoqiang; Lin, Qiaoya; Lian, Lichao; Qian, Yuan; Lu, Lisen; Zhang, Zhihong

    2016-03-01

    Breast cancer is one of the most harmful cancers in human. Its early diagnosis is expected to improve the patients' survival rate. X-ray computed tomography (CT) has been widely used in tumor detection for obtaining three-dimentional information. Fluorescence Molecular Tomography (FMT) imaging combined with near-infrared fluorescent dyes provides a powerful tool for the acquisition of molecular biodistribution information in deep tissues. Thus, the combination of CT and FMT imaging modalities allows us to better differentiate diseased tissues from normal tissues. Here we developed a tumor-targeting nanoparticle for dual-modality imaging based on a biocompatible HDL-mimicking peptide-phospholipid scaffold (HPPS) nanocarrier. By incorporation of CT contrast agents (iodinated oil) and far-infrared fluorescent dyes (DiR-BOA) into the hydrophobic core of HPPS, we obtained the FMT and CT signals simultaneously. Increased accumulation of the nanoparticles in the tumor lesions was achieved through the effect of the tumor-targeting peptide on the surface of nanoparticle. It resulted in excellent contrast between lesions and normal tissues. Together, the abilities to sensitively separate the lesions from adjacent normal tissues with the aid of a FMT/CT dual-model imaging approach make the targeting nanoparticles a useful tool for the diagnostics of breast cancer.

  1. Unusual Presentation of Bladder Paraganglioma: Comparison of (131)I MIBG SPECT/CT and (68)Ga DOTANOC PET/CT.

    PubMed

    Jain, Tarun Kumar; Basher, Rajender Kumar; Gupta, Nitin; Shukla, Jaya; Singh, Shrawan Kumar; Mittal, Bhagwant Rai

    2016-01-01

    Extraadrenal chromaffin cell-related tumors or paragangliomas are rare, especially in the bladder, accounting for less than 1% of cases. We report a 16-year-old boy who presented with hematuria and paroxysmal headache and was found to have a prostatic growth infiltrating the urinary bladder on anatomical imaging. Iodine-131 ((131)I) metaiodobenzylguanidine (MIBG) whole-body scanning and subsequently gallium-68 ((68)Ga) DOTANOC positron emission tomography/computed tomography (PET/CT) were performed. The MIBG scan revealed a non-tracer-avid soft-tissue mass, while DOTANOC PET/CT revealed a tracer-avid primary soft-tissue mass involving the urinary bladder and prostate with metastasis to the iliac lymph nodes. He underwent surgical management; histopathology of the surgical specimen revealed a bladder paraganglioma, whereas the prostate was found to be free of tumor.

  2. Unusual Presentation of Bladder Paraganglioma: Comparison of 131I MIBG SPECT/CT and 68Ga DOTANOC PET/CT

    PubMed Central

    Jain, Tarun Kumar; Basher, Rajender Kumar; Gupta, Nitin; Shukla, Jaya; Singh, Shrawan Kumar; Mittal, Bhagwant Rai

    2016-01-01

    Extraadrenal chromaffin cell-related tumors or paragangliomas are rare, especially in the bladder, accounting for less than 1% of cases. We report a 16-year-old boy who presented with hematuria and paroxysmal headache and was found to have a prostatic growth infiltrating the urinary bladder on anatomical imaging. Iodine-131 (131I) metaiodobenzylguanidine (MIBG) whole-body scanning and subsequently gallium-68 (68Ga) DOTANOC positron emission tomography/computed tomography (PET/CT) were performed. The MIBG scan revealed a non-tracer-avid soft-tissue mass, while DOTANOC PET/CT revealed a tracer-avid primary soft-tissue mass involving the urinary bladder and prostate with metastasis to the iliac lymph nodes. He underwent surgical management; histopathology of the surgical specimen revealed a bladder paraganglioma, whereas the prostate was found to be free of tumor. PMID:26912984

  3. Dynamic Contrast-Enhanced CT in Patients with Pancreatic Cancer.

    PubMed

    Eriksen, Rie Ø; Strauch, Louise S; Sandgaard, Michael; Kristensen, Thomas S; Nielsen, Michael B; Lauridsen, Carsten A

    2016-09-06

    The aim of this systematic review is to provide an overview of the use of Dynamic Contrast-enhanced Computed Tomography (DCE-CT) in patients with pancreatic cancer. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in PubMed, Cochrane Library, EMBASE, and Web of Science databases to identify all relevant publications. The QUADAS-2 tool was implemented to assess the risk of bias and applicability concerns of each included study. The initial literature search yielded 483 publications. Thirteen articles were included. Articles were categorized into three groups: nine articles concerning primary diagnosis or staging, one article about tumor response to treatment, and three articles regarding scan techniques. In exocrine pancreatic tumors, measurements of blood flow in eight studies and blood volume in seven studies were significantly lower in tumor tissue, compared with measurements in pancreatic tissue outside of tumor, or normal pancreatic tissue in control groups of healthy volunteers. The studies were heterogeneous in the number of patients enrolled and scan protocols. Perfusion parameters measured and analyzed by DCE-CT might be useful in the investigation of characteristic vascular patterns of exocrine pancreatic tumors. Further clinical studies are desired for investigating the potential of DCE-CT in pancreatic tumors.

  4. Dynamic Contrast-Enhanced CT in Patients with Pancreatic Cancer

    PubMed Central

    Eriksen, Rie Ø.; Strauch, Louise S.; Sandgaard, Michael; Kristensen, Thomas S.; Nielsen, Michael B.; Lauridsen, Carsten A.

    2016-01-01

    The aim of this systematic review is to provide an overview of the use of Dynamic Contrast-enhanced Computed Tomography (DCE-CT) in patients with pancreatic cancer. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in PubMed, Cochrane Library, EMBASE, and Web of Science databases to identify all relevant publications. The QUADAS-2 tool was implemented to assess the risk of bias and applicability concerns of each included study. The initial literature search yielded 483 publications. Thirteen articles were included. Articles were categorized into three groups: nine articles concerning primary diagnosis or staging, one article about tumor response to treatment, and three articles regarding scan techniques. In exocrine pancreatic tumors, measurements of blood flow in eight studies and blood volume in seven studies were significantly lower in tumor tissue, compared with measurements in pancreatic tissue outside of tumor, or normal pancreatic tissue in control groups of healthy volunteers. The studies were heterogeneous in the number of patients enrolled and scan protocols. Perfusion parameters measured and analyzed by DCE-CT might be useful in the investigation of characteristic vascular patterns of exocrine pancreatic tumors. Further clinical studies are desired for investigating the potential of DCE-CT in pancreatic tumors. PMID:27608045

  5. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  6. Accuracies of the synthesized monochromatic CT numbers and effective atomic numbers obtained with a rapid kVp switching dual energy CT scanner

    SciTech Connect

    Goodsitt, Mitchell M.; Christodoulou, Emmanuel G.; Larson, Sandra C.

    2011-04-15

    Purpose: This study was performed to investigate the accuracies of the synthesized monochromatic images and effective atomic number maps obtained with the new GE Discovery CT750 HD CT scanner. Methods: A Gammex-RMI model 467 tissue characterization phantom and the CT number linearity section of a Phantom Laboratory Catphan 600 phantom were scanned using the dual energy (DE) feature on the GE CT750 HD scanner. Synthesized monochromatic images at various energies between 40 and 120 keV and effective atomic number (Z{sub eff}) maps were generated. Regions of interest were placed within these images/maps to measure the average monochromatic CT numbers and average Z{sub eff} of the materials within these phantoms. The true Z{sub eff} values were either supplied by the phantom manufacturer or computed using Mayneord's equation. The linear attenuation coefficients for the true CT numbers were computed using the NIST XCOM program with the input of manufacturer supplied elemental compositions and densities. The effects of small variations in the assumed true densities of the materials were also investigated. Finally, the effect of body size on the accuracies of the synthesized monochromatic CT numbers was investigated using a custom lumbar section phantom with and without an external fat-mimicking ring. Results: Other than the Z{sub eff} of the simulated lung inserts in the tissue characterization phantom, which could not be measured by DECT, the Z{sub eff} values of all of the other materials in the tissue characterization and Catphan phantoms were accurate to 15%. The accuracies of the synthesized monochromatic CT numbers of the materials in both phantoms varied with energy and material. For the 40-120 keV range, RMS errors between the measured and true CT numbers in the Catphan are 8-25 HU when the true CT numbers were computed using the nominal plastic densities. These RMS errors improve to 3-12 HU for assumed true densities within the nominal density {+-}0.02 g

  7. TU-G-201-01: What Therapy Physicists Need to Know About CT and PET/CT: Terminology and Latest Developments

    SciTech Connect

    Hua, C.

    2015-06-15

    This session will update therapeutic physicists on technological advancements and radiation oncology features of commercial CT, MRI, and PET/CT imaging systems. Also described are physicists’ roles in every stage of equipment selection, purchasing, and operation, including defining specifications, evaluating vendors, making recommendations, and optimal and safe use of imaging equipment in radiation oncology environment. The first presentation defines important terminology of CT and PET/CT followed by a review of latest innovations, such as metal artifact reduction, statistical iterative reconstruction, radiation dose management, tissue classification by dual energy CT and spectral CT, improvement in spatial resolution and sensitivity in PET, and potentials of PET/MR. We will also discuss important technical specifications and items in CT and PET/CT purchasing quotes and their impacts. The second presentation will focus on key components in the request for proposal for a MRI simulator and how to evaluate vendor proposals. MRI safety issues in radiation Oncology, including MRI scanner Zones (4-zone design), will be discussed. Basic MR terminologies, important functionalities, and advanced features, which are relevant to radiation therapy, will be discussed. In the third presentation, justification of imaging systems for radiation oncology, considerations in room design and construction in a RO department, shared use with diagnostic radiology, staffing needs and training, clinical/research use cases and implementation, will be discussed. The emphasis will be on understanding and bridging the differences between diagnostic and radiation oncology installations, building consensus amongst stakeholders for purchase and use, and integrating imaging technologies into the radiation oncology environment. Learning Objectives: Learn the latest innovations of major imaging systems relevant to radiation therapy Be able to describe important technical specifications of CT, MRI

  8. Intraorbital Encephalocele Presenting with Exophthalmos and Orbital Dystopia : CT and MRI Findings.

    PubMed

    Asil, Kiyasettin; Gunduz, Yasemin; Yaldiz, Can; Aksoy, Yakup Ersel

    2015-01-01

    A 15-year-old female patient with progressive pulsatile exophthalmos caused by intraorbital encephalocele was evaluated with computed tomography (CT) and magnetic resonance imaging (MRI) in our clinic. She had no history of trauma or reconstructive surgery. When she was a little girl, she had undergone surgery for congenital glaucoma on the right eye. On the three-dimensional image of CT, a hypoplasic bone defect was observed in the greater wing of the right sphenoid bone. MRI and CT scan showed herniation through this defect of the arachnoid membrane and protruded cerebral tissue into the right orbita. Intraorbital encephalocele is an important entity that can cause pulsatile exophthalmos and blindness.

  9. Acute Coronary Artery Air Embolism Following CT-Guided Lung Biopsy

    SciTech Connect

    Mansour, Asem AbdelRaouf, Salah; Qandeel, Monther; Swaidan, Maisa

    2005-01-15

    CT-guided needle biopsy is a common procedure for obtaining a tissue diagnosis and consequently correctly managing patients. This procedure has many potential complications, ranging from simple pneumothorax or self-limiting hemoptysis to life-threatening pulmonary hemorrhage and air embolism. Though the latter is a rare complication of CT-guided needle biopsy, it has attracted a lot of interest. We report a case of right coronary air embolism resulting in myocardial infarction after a CT-guided percutaneous needle biopsy of the lung.

  10. High energy x-ray phase contrast CT using glancing-angle grating interferometers

    SciTech Connect

    Sarapata, A.; Stayman, J. W.; Siewerdsen, J. H.; Finkenthal, M.; Stutman, D.; Pfeiffer, F.

    2014-02-15

    Purpose: The authors present initial progress toward a clinically compatible x-ray phase contrast CT system, using glancing-angle x-ray grating interferometry to provide high contrast soft tissue images at estimated by computer simulation dose levels comparable to conventional absorption based CT. Methods: DPC-CT scans of a joint phantom and of soft tissues were performed in order to answer several important questions from a clinical setup point of view. A comparison between high and low fringe visibility systems is presented. The standard phase stepping method was compared with sliding window interlaced scanning. Using estimated dose values obtained with a Monte-Carlo code the authors studied the dependence of the phase image contrast on exposure time and dose. Results: Using a glancing angle interferometer at high x-ray energy (∼45 keV mean value) in combination with a conventional x-ray tube the authors achieved fringe visibility values of nearly 50%, never reported before. High fringe visibility is shown to be an indispensable parameter for a potential clinical scanner. Sliding window interlaced scanning proved to have higher SNRs and CNRs in a region of interest and to also be a crucial part of a low dose CT system. DPC-CT images of a soft tissue phantom at exposures in the range typical for absorption based CT of musculoskeletal extremities were obtained. Assuming a human knee as the CT target, good soft tissue phase contrast could be obtained at an estimated absorbed dose level around 8 mGy, similar to conventional CT. Conclusions: DPC-CT with glancing-angle interferometers provides improved soft tissue contrast over absorption CT even at clinically compatible dose levels (estimated by a Monte-Carlo computer simulation). Further steps in image processing, data reconstruction, and spectral matching could make the technique fully clinically compatible. Nevertheless, due to its increased scan time and complexity the technique should be thought of not as

  11. Registration of ultrasound to CT angiography of kidneys: a porcine phantom study

    NASA Astrophysics Data System (ADS)

    Xiang, Jing; Gill, Sean; Nguan, Christopher; Abolmaesumi, Purang; Rohling, Robert N.

    2010-02-01

    3D ultrasound (US) to computed tomography (CT) registration is a topic of significant interest because it can potentially improve many minimally invasive procedures such as laparoscopic partial nephrectomy. Partial nephrectomy patients often receive preoperative CT angiography, which helps define the important structures of the kidney such as the vasculature. Intraoperatively, dynamic real-time imaging information can be captured using ultrasound and compared with the preoperative data. Providing accurate registration between the two modalities would enhance navigation and guidance for the surgeon. However, one of the major problems of developing and evaluating registration techniques is obtaining sufficiently accurate and realistic phantom data especially for soft tissue. We present a detailed procedure for constructing tissue phantoms using porcine kidneys, which incorporates contrast agent into the tissue such that the kidneys appear representative of in vivo human CT angiography. These phantoms are also imaged with US and resemble US images from human patients. We then perform registration on corresponding CT and US datasets using a simulation-based algorithm. The method simulates an US image from the CT, generating an intermediate modality that resembles ultrasound. This simulated US is then registered to the original US dataset. Embedded fiducial markers provide a gold standard for registration. Being able to test our registration method on realistic datasets facilitates the development of novel CT to US registration techniques such that we can generate an effective method for human studies.

  12. FMT-PCCT: hybrid fluorescence molecular tomography-x-ray phase-contrast CT imaging of mouse models.

    PubMed

    Mohajerani, Pouyan; Hipp, Alexander; Willner, Marian; Marschner, Mathias; Trajkovic-Arsic, Marija; Ma, Xiaopeng; Burton, Neal C; Klemm, Uwe; Radrich, Karin; Ermolayev, Vladimir; Tzoumas, Stratis; Siveke, Jens T; Bech, Martin; Pfeiffer, Franz; Ntziachristos, Vasilis

    2014-07-01

    The implementation of hybrid fluorescence molecular tomography (FMT) and X-ray computed tomography (CT) has been shown to be a necessary development, not only for combining anatomical with functional and molecular contrast, but also for generating optical images of high accuracy. FMT affords highly sensitive 3-D imaging of fluorescence bio-distribution, but in stand-alone form it offers images of low resolution. It was shown that FMT accuracy significantly improves by considering anatomical priors from CT. Conversely, CT generally suffers from low soft tissue contrast. Therefore utilization of CT data as prior information in FMT inversion is challenging when different internal organs are not clearly differentiated. Instead, we combined herein FMT with emerging X-ray phase-contrast CT (PCCT). PCCT relies on phase shift differences in tissue to achieve soft tissue contrast superior to conventional CT. We demonstrate for the first time FMT-PCCT imaging of different animal models, where FMT and PCCT scans were performed in vivo and ex vivo, respectively. The results show that FMT-PCCT expands the potential of FMT in imaging lesions with otherwise low or no CT contrast, while retaining the cost benefits of CT and simplicity of hybrid device realizations. The results point to the most accurate FMT performance to date.

  13. Semantic analysis of SNOMED CT for a post-coordinated database of histopathology findings

    PubMed Central

    Campbell, Walter S; Campbell, James R; West, William W; McClay, James C; Hinrichs, Steven H

    2014-01-01

    Objective This research investigated the use of SNOMED CT to represent diagnostic tissue morphologies and notable tissue architectures typically found within a pathologist's microscopic examination report to identify gaps in expressivity of SNOMED CT for use in anatomic pathology. Methods 24 breast biopsy cases were reviewed by two board certified surgical pathologists who independently described the diagnostically important tissue architectures and diagnostic morphologies observed by microscopic examination. In addition, diagnostic comments and details were extracted from the original diagnostic pathology report. 95 unique clinical statements were extracted from 13 malignant and 11 benign breast needle biopsy cases. Results 75% of the inventoried diagnostic terms and statements could be represented by valid SNOMED CT expressions. The expressions included one pre-coordinated expression and 73 post-coordinated expressions. No valid SNOMED CT expressions could be identified or developed to unambiguously assert the meaning of 21 statements (ie, 25% of inventoried clinical statements). Evaluation of the findings indicated that SNOMED CT lacked sufficient definitional expressions or the SNOMED CT concept model prohibited use of certain defined concepts needed to describe the numerous, diagnostically important tissue architectures and morphologic changes found within a surgical pathology microscopic examination. Conclusions Because information gathered during microscopic histopathology examination provides the basis of pathology diagnoses, additional concept definitions for tissue morphometries and modifications to the SNOMED CT concept model are needed and suggested to represent detailed histopathologic findings in computable fashion for purposes of patient information exchange and research. Trial registration number UNMC Institutional Review Board ID# 342-11-EP. PMID:24833774

  14. Spectral optimization for micro-CT

    SciTech Connect

    Hupfer, Martin; Nowak, Tristan; Brauweiler, Robert; Eisa, Fabian; Kalender, Willi A.

    2012-06-15

    Purpose: To optimize micro-CT protocols with respect to x-ray spectra and thereby reduce radiation dose at unimpaired image quality. Methods: Simulations were performed to assess image contrast, noise, and radiation dose for different imaging tasks. The figure of merit used to determine the optimal spectrum was the dose-weighted contrast-to-noise ratio (CNRD). Both optimal photon energy and tube voltage were considered. Three different types of filtration were investigated for polychromatic x-ray spectra: 0.5 mm Al, 3.0 mm Al, and 0.2 mm Cu. Phantoms consisted of water cylinders of 20, 32, and 50 mm in diameter with a central insert of 9 mm which was filled with different contrast materials: an iodine-based contrast medium (CM) to mimic contrast-enhanced (CE) imaging, hydroxyapatite to mimic bone structures, and water with reduced density to mimic soft tissue contrast. Validation measurements were conducted on a commercially available micro-CT scanner using phantoms consisting of water-equivalent plastics. Measurements on a mouse cadaver were performed to assess potential artifacts like beam hardening and to further validate simulation results. Results: The optimal photon energy for CE imaging was found at 34 keV. For bone imaging, optimal energies were 17, 20, and 23 keV for the 20, 32, and 50 mm phantom, respectively. For density differences, optimal energies varied between 18 and 50 keV for the 20 and 50 mm phantom, respectively. For the 32 mm phantom and density differences, CNRD was found to be constant within 2.5% for the energy range of 21-60 keV. For polychromatic spectra and CMs, optimal settings were 50 kV with 0.2 mm Cu filtration, allowing for a dose reduction of 58% compared to the optimal setting for 0.5 mm Al filtration. For bone imaging, optimal tube voltages were below 35 kV. For soft tissue imaging, optimal tube settings strongly depended on phantom size. For 20 mm, low voltages were preferred. For 32 mm, CNRD was found to be almost independent of

  15. Predicting stroke outcome using DCE-CT measured blood velocity

    NASA Astrophysics Data System (ADS)

    Oosterbroek, Jaap; Bennink, Edwin; Dankbaar, Jan Willem; Horsch, Alexander D.; Viergever, Max A.; Velthuis, Birgitta K.; de Jong, Hugo W. A. M.

    2015-03-01

    CT plays an important role in the diagnosis of acute stroke patients. Dynamic contrast enhanced CT (DCE-CT) can estimate local tissue perfusion and extent of ischemia. However, hemodynamic information of the large intracranial vessels may also be obtained from DCE-CT data and may contain valuable diagnostic information. We describe a novel method to estimate intravascular blood velocity (IBV) in large cerebral vessels using DCE-CT data, which may be useful to help predict stroke outcome. DCE-CT scans from 34 patients with isolated M1 occlusions were included from a large prospective multi-center cohort study of patients with acute ischemic stroke. Gaussians fitted to the intravascular data yielded the time-to-peak (TTP) and cerebral-blood-volume (CBV). IBV was computed by taking the inverse of the TTP gradient magnitude. Voxels with a CBV of at least 10% of the CBV found in the arterial input function were considered part of a vessel. Mid-sagittal planes were drawn manually and averages of the IBV over all vessel-voxels (arterial and venous) were computed for each hemisphere. Mean-hemisphere IBV differences, mean-hemisphere TTP differences, and hemisphere vessel volume differences were used to differentiate between patients with good and bad outcome (modified Rankin Scale score <3 versus ≥3 at 90 days) using ROC analysis. AUCs from the ROC for IBV, TTP, and vessel volume were 0.80, 0.67 and 0.62 respectively. In conclusion, IBV was found to be a better predictor of patient outcome than the parameters used to compute it and may be a promising new parameter for stroke outcome prediction.

  16. Enhanced transbuccal salmon calcitonin (sCT) delivery: effect of chemical enhancers and electrical assistance on in vitro sCT buccal permeation.

    PubMed

    Oh, Dong-Ho; Chun, Kyeung-Hwa; Jeon, Sang-Ok; Kang, Jeong-Won; Lee, Sangkil

    2011-10-01

    This study investigates the combined effect of absorption enhancers and electrical assistance on transbuccal salmon calcitonin (sCT) delivery, using fresh swine buccal tissue. We placed 200 IU (40 μg/mL) of each sCT formulation--containing various concentrations of ethanol, N-acetyl-L-cysteine (NAC), and sodium deoxyglycocholate (SDGC)--onto the donor part of a Franz diffusion cell. Then, 0.5 mA/cm(2) of fixed anodal current was applied alone or combined with chemical enhancers. The amount of permeated sCT was analyzed using an ELISA kit, and biophysical changes of the buccal mucosa were investigated using FT-IR spectroscopy, and hematoxylin-eosin staining methods were used to evaluate histological alteration of the buccal tissues. The flux (J(s)) of sCT increased with the addition of absorption enhancer groups, but it was significantly enhanced by the application of anodal iontophoresis (ITP). FT-IR study revealed that all groups caused an increase in lipid fluidity but only the groups containing SDGC showed statistically significant difference. Although the histological data of SDGC groups showed a possibility for tissue damage, the present enhancing methods appear to be safe. In conclusion, the combination of absorption enhancers and electrical assistance is a potential strategy for the enhancement of transbuccal sCT delivery.

  17. Extracting information from previous full-dose CT scan for knowledge-based Bayesian reconstruction of current low-dose CT images

    PubMed Central

    Zhang, Hao; Han, Hao; Liang, Zhengrong; Hu, Yifan; Liu, Yan; Moore, William; Ma, Jianhua; Lu, Hongbing

    2015-01-01

    Markov random field (MRF) model has been widely employed in edge-preserving regional noise smoothing penalty to reconstruct piece-wise smooth images in the presence of noise, such as in low-dose computed tomography (LdCT). While it preserves edge sharpness, its regional smoothing may sacrifice tissue image textures, which have been recognized as useful imaging biomarkers, and thus it may compromise clinical tasks such as differentiating malignant vs. benign lesions, e.g., lung nodules or colon polyps. This study aims to shift the edge-preserving regional noise smoothing paradigm to texture-preserving framework for LdCT image reconstruction while retaining the advantage of MRF’s neighborhood system on edge preservation. Specifically, we adapted the MRF model to incorporate the image textures of muscle, fat, bone, lung, etc. from previous full-dose CT (FdCT) scan as a priori knowledge for texture-preserving Bayesian reconstruction of current LdCT images. To show the feasibility of the proposed reconstruction framework, experiments using clinical patient scans were conducted. The experimental outcomes showed a dramatic gain by the a priori knowledge for LdCT image reconstruction using the commonly-used Haralick texture measures. Thus, it is conjectured that the texture-preserving LdCT reconstruction has advantages over the edge-preserving regional smoothing paradigm for texture-specific clinical applications. PMID:26561284

  18. 3D Ultrasound Can Contribute to Planning CT to Define the Target for Partial Breast Radiotherapy

    SciTech Connect

    Berrang, Tanya S.; Truong, Pauline T. Popescu, Carmen; Drever, Laura; Kader, Hosam A.; Hilts, Michelle L.; Mitchell, Tracy; Soh, S.Y.; Sands, Letricia; Silver, Stuart; Olivotto, Ivo A.

    2009-02-01

    Purpose: The role of three-dimensional breast ultrasound (3D US) in planning partial breast radiotherapy (PBRT) is unknown. This study evaluated the accuracy of coregistration of 3D US to planning computerized tomography (CT) images, the seroma contouring consistency of radiation oncologists using the two imaging modalities and the clinical situations in which US was associated with improved contouring consistency compared to CT. Materials and Methods: Twenty consecutive women with early-stage breast cancer were enrolled prospectively after breast-conserving surgery. Subjects underwent 3D US at CT simulation for adjuvant RT. Three radiation oncologists independently contoured the seroma on separate CT and 3D US image sets. Seroma clarity, seroma volumes, and interobserver contouring consistency were compared between the imaging modalities. Associations between clinical characteristics and seroma clarity were examined using Pearson correlation statistics. Results: 3D US and CT coregistration was accurate to within 2 mm or less in 19/20 (95%) cases. CT seroma clarity was reduced with dense breast parenchyma (p = 0.035), small seroma volume (p < 0.001), and small volume of excised breast tissue (p = 0.01). US seroma clarity was not affected by these factors (p = NS). US was associated with improved interobserver consistency compared with CT in 8/20 (40%) cases. Of these 8 cases, 7 had low CT seroma clarity scores and 4 had heterogeneously to extremely dense breast parenchyma. Conclusion: 3D US can be a useful adjunct to CT in planning PBRT. Radiation oncologists were able to use US images to contour the seroma target, with improved interobserver consistency compared with CT in cases with dense breast parenchyma and poor CT seroma clarity.

  19. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

    NASA Astrophysics Data System (ADS)

    Welch, D.; Harken, A. D.; Randers-Pehrson, G.; Brenner, D. J.

    2015-05-01

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions.

  20. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies.

    PubMed

    Welch, D; Harken, A D; Randers-Pehrson, G; Brenner, D J

    2015-05-07

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions.

  1. Weight preserving image registration for monitoring disease progression in lung CT.

    PubMed

    Gorbunova, Vladlena; Lol, Pechin; Ashraf, Haseem; Dirksen, Asger; Nielsen, Mads; de Bruijne, Marleen

    2008-01-01

    We present a new image registration based method for monitoring regional disease progression in longitudinal image studies of lung disease. A free-form image registration technique is used to match a baseline 3D CT lung scan onto a following scan. Areas with lower intensity in the following scan compared with intensities in the deformed baseline image indicate local loss of lung tissue that is associated with progression of emphysema. To account for differences in lung intensity owing to differences in the inspiration level in the two scans rather than disease progression, we propose to adjust the density of lung tissue with respect to local expansion or compression such that the total weight of the lungs is preserved during deformation. Our method provides a good estimation of regional destruction of lung tissue for subjects with a significant difference in inspiration level between CT scans and may result in a more sensitive measure of disease progression than standard quantitative CT measures.

  2. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

    PubMed Central

    Welch, D; Harken, A D; Randers-Pehrson, G; Brenner, D J

    2015-01-01

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions. PMID:25860401

  3. Synchrotron μCT imaging of bone, titanium implants and bone substitutes - a systematic review of the literature.

    PubMed

    Neldam, Camilla Albeck; Pinholt, Else Marie

    2014-09-01

    Today X-ray micro computer tomography (μCT) imaging is used to investigate bone microarchitecture. μCT imaging is obtained by polychromatic X-ray beams, resulting in images with beam hardening artifacts, resolution levels at 10 μm, geometrical blurring, and lack of contrasts. When μCT is coupled to synchrotron sources (SRμCT) a spatial resolution up to one tenth of a μm may be achieved. A review of the literature concerning SRμCT was performed to investigate its usability and its strength in visualizing fine bone structures, vessels, and microarchitecture of bone. Although mainly limited to in vitro examinations, SRμCT is considered as a gold standard to image trabecular bone microarchitecture since it is possible in a 3D manner to visualize fine structural elements within mineralized tissue such as osteon boundaries, rods and plates structures, cement lines, and differences in mineralization.

  4. X-ray microscopy of soft and hard human tissues

    SciTech Connect

    Müller, Bert Schulz, Georg Deyhle, Hans Stalder, Anja K. Ilgenstein, Bernd Holme, Margaret N. Hieber, Simone E.; Beckmann, Felix

    2016-01-28

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  5. X-ray microscopy of soft and hard human tissues

    NASA Astrophysics Data System (ADS)

    Müller, Bert; Schulz, Georg; Deyhle, Hans; Stalder, Anja K.; Ilgenstein, Bernd; Holme, Margaret N.; Weitkamp, Timm; Beckmann, Felix; Hieber, Simone E.

    2016-01-01

    The simultaneous post mortem visualization of soft and hard tissues using absorption-based CT remains a challenge. If the photon energy is optimized for the visualization of hard tissue, the surrounding soft tissue components are almost X-ray transparent. Therefore, the combination with other modalities such as phase-contrast CT, magnetic resonance microscopy, and histology is essential to detect the anatomical features. The combination of the 2D and 3D data sets using sophisticated segmentation and registration tools allows for conclusions about otherwise inaccessible anatomical features essential for improved patient treatments.

  6. Tissue repair

    PubMed Central

    2010-01-01

    As living beings that encounter every kind of traumatic event from paper cut to myocardial infarction, we must possess ways to heal damaged tissues. While some animals are able to regrow complete body parts following injury (such as the earthworm who grows a new head following bisection), humans are sadly incapable of such feats. Our means of recovery following tissue damage consists largely of repair rather than pure regeneration. Thousands of times in our lives, a meticulously scripted but unseen wound healing drama plays, with cells serving as actors, extracellular matrix as the setting and growth factors as the means of communication. This article briefly reviews the cells involved in tissue repair, their signaling and proliferation mechanisms and the function of the extracellular matrix, then presents the actors and script for the three acts of the tissue repair drama. PMID:21220961

  7. Dosimetry in small-animal CT using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Lee, C.-L.; Park, S.-J.; Jeon, P.-H.; Jo, B.-D.; Kim, H.-J.

    2016-01-01

    Small-animal computed tomography (micro-CT) imaging devices are increasingly being used in biological research. While investigators are mainly interested in high-contrast, low-noise, and high-resolution anatomical images, relatively large radiation doses are required, and there is also growing concern over the radiological risk from preclinical experiments. This study was conducted to determine the radiation dose in a mouse model for dosimetric estimates using the GEANT4 application for tomographic emission simulations (GATE) and to extend its techniques to various small-animal CT applications. Radiation dose simulations were performed with the same parameters as those for the measured micro-CT data, using the MOBY phantom, a pencil ion chamber and an electrometer with a CT detector. For physical validation of radiation dose, absorbed dose of brain and liver in mouse were evaluated to compare simulated results with physically measured data using thermoluminescent dosimeters (TLDs). The mean difference between simulated and measured data was less than 2.9% at 50 kVp X-ray source. The absorbed doses of 37 brain tissues and major organs of the mouse were evaluated according to kVp changes. The absorbed dose over all of the measurements in the brain (37 types of tissues) consistently increased and ranged from 42.4 to 104.0 mGy. Among the brain tissues, the absorbed dose of the hypothalamus (157.8-414.30 mGy) was the highest for the beams at 50-80 kVp, and that of the corpus callosum (11.2-26.6 mGy) was the lowest. These results can be used as a dosimetric database to control mouse doses and preclinical targeted radiotherapy experiments. In addition, to accurately calculate the mouse-absorbed dose, the X-ray spectrum, detector alignment, and uncertainty in the elemental composition of the simulated materials must be accurately modeled.

  8. [Gallstone ileus. Abdominal CT usefulness].

    PubMed

    Sukkarieh, F; Brasseur, P; Bissen, L

    2004-06-01

    The authors report the case of a 93-year old woman referred to the emergency department and presenting with an intestinal obstruction. Abdominal CT reveals a biliary ileus caused by the migration and the impaction of a 3 cm gallstone in the small bowel. Surgical treatment by enterolithotomy was successful. In over 90% of cases, gallstone ileus is a complication of cholelithiasis and accounts for 25% of intestinal obstruction in patients over 65 years. To reduce morbidity and mortality, early diagnosis and prompt treatment are essential. Abdominal CT-scan is the gold standard technique.

  9. Ontological analysis of SNOMED CT

    PubMed Central

    Héja, Gergely; Surján, György; Varga, Péter

    2008-01-01

    Background SNOMED CT is the most comprehensive medical terminology. However, its use for intelligent services based on formal reasoning is questionable. Methods The analysis of the structure of SNOMED CT is based on the formal top-level ontology DOLCE. Results The analysis revealed several ontological and knowledge-engineering errors, the most important are errors in the hierarchy (mostly from an ontological point of view, but also regarding medical aspects) and the mixing of subsumption relations with other types (mostly 'part of'). Conclusion The found errors impede formal reasoning. The paper presents a possible way to correct these problems. PMID:19007445

  10. Tissue Issues

    ERIC Educational Resources Information Center

    Metz, James

    2016-01-01

    Every day, 27,000 trees are used to make bathroom tissue. Americans use an average of 23.6 rolls per person per year, and more than 7 billion rolls of toilet paper are sold yearly in the United States alone. Perhaps the amount of bathroom tissue used can be reduced by changing the dimensions of the paper or the core. This brief article presents…

  11. MAGE-C2/CT10 Protein Expression Is an Independent Predictor of Recurrence in Prostate Cancer

    PubMed Central

    Mortezavi, Ashkan; Provenzano, Maurizio; Sais, Giovanni; Hermanns, Thomas; Sulser, Tullio; Jungbluth, Achim A.; Old, Lloyd J.; Kristiansen, Glen; van den Broek, Maries; Moch, Holger

    2011-01-01

    The cancer-testis (CT) family of antigens is expressed in a variety of malignant neoplasms. In most cases, no CT antigen is found in normal tissues, except in testis, making them ideal targets for cancer immunotherapy. A comprehensive analysis of CT antigen expression has not yet been reported in prostate cancer. MAGE-C2/CT-10 is a novel CT antigen. The objective of this study was to analyze extent and prognostic significance of MAGE-C2/CT10 protein expression in prostate cancer. 348 prostate carcinomas from consecutive radical prostatectomies, 29 castration-refractory prostate cancer, 46 metastases, and 45 benign hyperplasias were immunohistochemically analyzed for MAGE-C2/CT10 expression using tissue microarrays. Nuclear MAGE-C2/CT10 expression was identified in only 3.3% primary prostate carcinomas. MAGE-C2/CT10 protein expression was significantly more frequent in metastatic (16.3% positivity) and castration-resistant prostate cancer (17% positivity; p<0.001). Nuclear MAGE-C2/CT10 expression was identified as predictor of biochemical recurrence after radical prostatectomy (p = 0.015), which was independent of preoperative PSA, Gleason score, tumor stage, and surgical margin status in multivariate analysis (p<0.05). MAGE-C2/CT10 expression in prostate cancer correlates with the degree of malignancy and indicates a higher risk for biochemical recurrence after radical prostatectomy. Further, the results suggest MAGE-C2/CT10 as a potential target for adjuvant and palliative immunotherapy in patients with prostate cancer. PMID:21754986

  12. CT imaging with a mobile C-arm prototype

    NASA Astrophysics Data System (ADS)

    Cheryauka, Arvi; Tubbs, David; Langille, Vinton; Kalya, Prabhanjana; Smith, Brady; Cherone, Rocco

    2008-03-01

    Mobile X-ray imagery is an omnipresent tool in conventional musculoskeletal and soft tissue applications. The next generation of mobile C-arm systems can provide clinicians of minimally-invasive surgery and pain management procedures with both real-time high-resolution fluoroscopy and intra-operative CT imaging modalities. In this study, we research two C-arm CT experimental system configurations and evaluate their imaging capabilities. In a non-destructive evaluation configuration, the X-ray Tube - Detector assembly is stationary while an imaging object is placed on a rotating table. In a medical imaging configuration, the C-arm gantry moves around the patient and the table. In our research setting, we connect the participating devices through a Mobile X-Ray Imaging Environment known as MOXIE. MOXIE is a set of software applications for internal research at GE Healthcare - Surgery and used to examine imaging performance of experimental systems. Anthropomorphic phantom volume renderings and orthogonal slices of reconstructed images are obtained and displayed. The experimental C-arm CT results show CT-like image quality that may be suitable for interventional procedures, real-time data management, and, therefore, have great potential for effective use on the clinical floor.

  13. Low-dose interpolated average CT for attenuation correction in cardiac PET/CT

    NASA Astrophysics Data System (ADS)

    Wu, Tung-Hsin; Zhang, Geoffrey; Wang, Shyh-Jen; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Huang, Tzung-Chi

    2010-07-01

    Because of the advantages in the use of high photon flux and thus the short scan times of CT imaging, the traditional 68Ge scans for positron emission tomography (PET) image attenuation correction have been replaced by CT scans in the modern PET/CT technology. The combination of fast CT scan and slow PET scan often causes image misalignment between the PET and CT images due to respiration motion. Use of the average CT derived from cine CT images is reported to reduce such misalignment. However, the radiation dose to patients is higher with cine CT scans. This study introduces a method that uses breath-hold CT images and their interpolations to generate the average CT for PET image attenuation correction. Breath-hold CT sets are taken at end-inspiration and end-expiration. Deformable image registration is applied to generate a voxel-to-voxel motion matrix between the two CT sets. The motion is equally divided into 5 steps from inspiration to expiration and 5 steps from expiration to inspiration, generating a total of 8 phases of interpolated CT sets. An average CT image is generated from all the 10 phase CT images, including original inhale/exhale CT and 8 interpolated CT sets. Quantitative comparison shows that the reduction of image misalignment artifacts using the average CT from the interpolation technique for PET attenuation correction is at a similar level as that using cine average CT, while the dose to the patient from the CT scans is reduced significantly. The interpolated average CT method hence provides a low dose alternative to cine CT scans for PET attenuation correction.

  14. The effects of mapping CT images to Monte Carlo materials on GEANT4 proton simulation accuracy

    SciTech Connect

    Barnes, Samuel; McAuley, Grant; Slater, James; Wroe, Andrew

    2013-04-15

    Purpose: Monte Carlo simulations of radiation therapy require conversion from Hounsfield units (HU) in CT images to an exact tissue composition and density. The number of discrete densities (or density bins) used in this mapping affects the simulation accuracy, execution time, and memory usage in GEANT4 and other Monte Carlo code. The relationship between the number of density bins and CT noise was examined in general for all simulations that use HU conversion to density. Additionally, the effect of this on simulation accuracy was examined for proton radiation. Methods: Relative uncertainty from CT noise was compared with uncertainty from density binning to determine an upper limit on the number of density bins required in the presence of CT noise. Error propagation analysis was also performed on continuously slowing down approximation range calculations to determine the proton range uncertainty caused by density binning. These results were verified with Monte Carlo simulations. Results: In the presence of even modest CT noise (5 HU or 0.5%) 450 density bins were found to only cause a 5% increase in the density uncertainty (i.e., 95% of density uncertainty from CT noise, 5% from binning). Larger numbers of density bins are not required as CT noise will prevent increased density accuracy; this applies across all types of Monte Carlo simulations. Examining uncertainty in proton range, only 127 density bins are required for a proton range error of <0.1 mm in most tissue and <0.5 mm in low density tissue (e.g., lung). Conclusions: By considering CT noise and actual range uncertainty, the number of required density bins can be restricted to a very modest 127 depending on the application. Reducing the number of density bins provides large memory and execution time savings in GEANT4 and other Monte Carlo packages.

  15. CT effective dose per dose length product using ICRP 103 weighting factors

    SciTech Connect

    Huda, Walter; Magill, Dennise; He Wenjun

    2011-03-15

    Purpose: To generate effective dose per unit dose length product (E/DLP) conversion factors incorporating ICRP Publication 103 tissue weighting factors. Methods: Effective doses for CT examinations were obtained using the IMPACT Dosimetry Calculator using all 23 dose data sets that are offered by this spreadsheet. CT examinations were simulated for scans performed along the patient long axis for each dosimetry data set using a 4 cm beam width ranging from the upper thighs to top of the head. Five basic body regions (head, neck, chest, abdomen, and pelvis), as well as combinations of the regions (head/neck, chest/abdomen, abdomen/pelvis, and chest/abdomen/pelvis) and whole body CT scans were investigated. Correction factors were generated that can be applied to convert E/DLP conversion factors based on ICRP 60 data to conversion factors that are valid for ICRP 103 data (i.e., E{sub 103}/E{sub 60}). Results: Use of ICRP 103 weighting factors increase effective doses for head scans by {approx}11%, for chest scans by {approx}20%, and decrease effective doses for pelvis scans by {approx}25%. Current E/DLP conversion factors are estimated to be 2.4 {mu}Sv/mGy cm for head CT examinations and range between 14 and 20 {mu}Sv/mGy cm for body CT examinations. Conclusions: Factors that enable patient CT doses to be adjusted to account for ICRP 103 tissue weighting factors are provided, which result in E/DLP factors that were increased in head and chest CT, reduced in pelvis CT, and showed no marked change in neck and abdomen CT.

  16. CT angiography - arms and legs

    MedlinePlus

    ... combines a CT scan with the injection of dye. This technique is able to create pictures of ... Some exams require a special dye, called contrast, to be injected into your body before the test. Contrast helps certain areas show up better on the x- ...

  17. Pocket atlas of normal CT anatomy

    SciTech Connect

    Weinstein, J.B.; Lee, J.K.T.; Sagel, S.S.

    1985-01-01

    This book is a quick reference for interpreting CT scans of the extracranial organs. This collection of 41 CT scans covers all the major organs of the body: neck and larynx; chest; abdomen; male pelvis; and female pelvis.

  18. TU-G-BRA-02: Can We Extract Lung Function Directly From 4D-CT Without Deformable Image Registration?

    SciTech Connect

    Kipritidis, J; Woodruff, H; Counter, W; Keall, P; Hofman, M; Siva, S; Callahan, J; Le Roux, P; Hardcastle, N

    2015-06-15

    Purpose: Dynamic CT ventilation imaging (CT-VI) visualizes air volume changes in the lung by evaluating breathing-induced lung motion using deformable image registration (DIR). Dynamic CT-VI could enable functionally adaptive lung cancer radiation therapy, but its sensitivity to DIR parameters poses challenges for validation. We hypothesize that a direct metric using CT parameters derived from Hounsfield units (HU) alone can provide similar ventilation images without DIR. We compare the accuracy of Direct and Dynamic CT-VIs versus positron emission tomography (PET) images of inhaled {sup 68}Ga-labelled nanoparticles (‘Galligas’). Methods: 25 patients with lung cancer underwent Galligas 4D-PET/CT scans prior to radiation therapy. For each patient we produced three CT- VIs. (i) Our novel method, Direct CT-VI, models blood-gas exchange as the product of air and tissue density at each lung voxel based on time-averaged 4D-CT HU values. Dynamic CT-VIs were produced by evaluating: (ii) regional HU changes, and (iii) regional volume changes between the exhale and inhale 4D-CT phase images using a validated B-spline DIR method. We assessed the accuracy of each CT-VI by computing the voxel-wise Spearman correlation with free-breathing Galligas PET, and also performed a visual analysis. Results: Surprisingly, Direct CT-VIs exhibited better global correlation with Galligas PET than either of the dynamic CT-VIs. The (mean ± SD) correlations were (0.55 ± 0.16), (0.41 ± 0.22) and (0.29 ± 0.27) for Direct, Dynamic HU-based and Dynamic volume-based CT-VIs respectively. Visual comparison of Direct CT-VI to PET demonstrated similarity for emphysema defects and ventral-to-dorsal gradients, but inability to identify decreased ventilation distal to tumor-obstruction. Conclusion: Our data supports the hypothesis that Direct CT-VIs are as accurate as Dynamic CT-VIs in terms of global correlation with Galligas PET. Visual analysis, however, demonstrated that different CT

  19. Fast and automatic ultrasound simulation from CT images.

    PubMed

    Cong, Weijian; Yang, Jian; Liu, Yue; Wang, Yongtian

    2013-01-01

    Ultrasound is currently widely used in clinical diagnosis because of its fast and safe imaging principles. As the anatomical structures present in an ultrasound image are not as clear as CT or MRI. Physicians usually need advance clinical knowledge and experience to distinguish diseased tissues. Fast simulation of ultrasound provides a cost-effective way for the training and correlation of ultrasound and the anatomic structures. In this paper, a novel method is proposed for fast simulation of ultrasound from a CT image. A multiscale method is developed to enhance tubular structures so as to simulate the blood flow. The acoustic response of common tissues is generated by weighted integration of adjacent regions on the ultrasound propagation path in the CT image, from which parameters, including attenuation, reflection, scattering, and noise, are estimated simultaneously. The thin-plate spline interpolation method is employed to transform the simulation image between polar and rectangular coordinate systems. The Kaiser window function is utilized to produce integration and radial blurring effects of multiple transducer elements. Experimental results show that the developed method is very fast and effective, allowing realistic ultrasound to be fast generated. Given that the developed method is fully automatic, it can be utilized for ultrasound guided navigation in clinical practice and for training purpose.

  20. A biological phantom for evaluation of CT image reconstruction algorithms

    NASA Astrophysics Data System (ADS)

    Cammin, J.; Fung, G. S. K.; Fishman, E. K.; Siewerdsen, J. H.; Stayman, J. W.; Taguchi, K.

    2014-03-01

    In recent years, iterative algorithms have become popular in diagnostic CT imaging to reduce noise or radiation dose to the patient. The non-linear nature of these algorithms leads to non-linearities in the imaging chain. However, the methods to assess the performance of CT imaging systems were developed assuming the linear process of filtered backprojection (FBP). Those methods may not be suitable any longer when applied to non-linear systems. In order to evaluate the imaging performance, a phantom is typically scanned and the image quality is measured using various indices. For reasons of practicality, cost, and durability, those phantoms often consist of simple water containers with uniform cylinder inserts. However, these phantoms do not represent the rich structure and patterns of real tissue accurately. As a result, the measured image quality or detectability performance for lesions may not reflect the performance on clinical images. The discrepancy between estimated and real performance may be even larger for iterative methods which sometimes produce "plastic-like", patchy images with homogeneous patterns. Consequently, more realistic phantoms should be used to assess the performance of iterative algorithms. We designed and constructed a biological phantom consisting of porcine organs and tissue that models a human abdomen, including liver lesions. We scanned the phantom on a clinical CT scanner and compared basic image quality indices between filtered backprojection and an iterative reconstruction algorithm.

  1. Abdominal CT findings in small bowel perforation.

    PubMed

    Zissin, R; Osadchy, A; Gayer, G

    2009-02-01

    Small bowel perforation is an emergent medical condition for which the diagnosis is usually not made clinically but by CT, a common imaging modality used for the diagnosis of acute abdomen. Direct CT features that suggest perforation include extraluminal air and oral contrast, which are often associated with secondary CT signs of bowel pathology. This pictorial review illustrates the CT findings of small bowel perforation caused by various clinical entities.

  2. CT Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... الأشعة المقطعية الحاسوبية - العربية Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) CT (Computerized Tomography) Scan CT ( ... 扫描 - 简体中文 (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (繁體中文) CT (Computerized Tomography) Scan CT ( ...

  3. Minimizing artifacts resulting from respiratory and cardiac motion by optimization of the transmission scan in cardiac PET/CT

    SciTech Connect

    Nye, Jonathon A.; Esteves, Fabio; Votaw, John R.

    2007-06-15

    The introduction of positron emission/computed tomography (PET/CT) systems coupled with multidetector CT arrays has greatly increased the amount of clinical information in myocardial perfusion studies. The CT acquisition serves the dual role of providing high spatial anatomical detail and attenuation correction for PET. However, the differences between the interaction of respiratory and cardiac cycles in the CT and PET acquisitions presents a challenge when using the CT to determine PET attenuation correction. Three CT attenuation correction protocols were tested for their ability to produce accurate emission images: gated, a step mode acquisition covering the diastolic heart phase; normal, a high-pitch helical CT; and slow, a low-pitch, low-temporal-resolution helical CT. The amount of cardiac tissue in the emission image that overlaid lung tissue in the transmission image was used as the measure of mismatch between acquisitions. Phantom studies simulating misalignment of the heart between the transmission and emission sequences were used to correlate the amount of mismatch with the artificial defect changes in the emission image. Consecutive patients were studied prospectively with either paired gated (diastolic phase, 120 kVp, 280 mA, 2.6 s) and slow CT (0.562:1 pitch, 120 kVp, Auto-mA, 16 s) or paired normal (0.938:1 pitch, 120 kVp, Auto-mA, 4.8 s) and slow CT protocols, prior to a Rb-82 perfusion study. To determine the amount of mismatch, the transmission and emission images were converted to binary representations of attenuating tissue and cardiac tissue and overlaid using their native registration. The number of cardiac tissue pixels from the emission image present in the CT lung field yielded the magnitude of misalignment represented in terms of volume, of where a small volume indicates better registration. Acquiring a slow CT improved registration between the transmission and emission acquisitions compared to the gated and normal CT protocols. The volume

  4. Tissue Classification

    SciTech Connect

    Robinson, David Gerald

    2015-01-01

    The project began as a e ort to support InLight and Lumidigm. With the sale of the companies to a non-New Mexico entity, the project then focused on supporting a new company Medici Technologies. The Small Business (SB) is attempting to quantify glucose in tissue using a series of short interferometer scans of the nger. Each scan is produced from a novel presentation of the nger to the device. The intent of the project is to identify and, if possible, implement improved methods for classi cation, feature selection, and training to improve the performance of predictive algorithms used for tissue classi cation.

  5. Perfusion measurements by micro-CT using prior image constrained compressed sensing (PICCS): initial phantom results.

    PubMed

    Nett, Brian E; Brauweiler, Robert; Kalender, Willi; Rowley, Howard; Chen, Guang-Hong

    2010-04-21

    Micro-CT scanning has become an accepted standard for anatomical imaging in small animal disease and genome mutation models. Concurrently, perfusion imaging via tracking contrast dynamics after injection of an iodinated contrast agent is a well-established tool for clinical CT scanners. However, perfusion imaging is not yet commercially available on the micro-CT platform due to limitations in both radiation dose and temporal resolution. Recent hardware developments in micro-CT scanners enable continuous imaging of a given volume through the use of a slip-ring gantry. Now that dynamic CT imaging is feasible, data may be acquired to measure tissue perfusion using a micro-CT scanner (CT Imaging, Erlangen, Germany). However, rapid imaging using micro-CT scanners leads to high image noise in individual time frames. Using the standard filtered backprojection (FBP) image reconstruction, images are prohibitively noisy for calculation of voxel-by-voxel perfusion maps. In this study, we apply prior image constrained compressed sensing (PICCS) to reconstruct images with significantly lower noise variance. In perfusion phantom experiments performed on a micro-CT scanner, the PICCS reconstruction enabled a reduction to 1/16 of the noise variance of standard FBP reconstruction, without compromising the spatial or temporal resolution. This enables a significant increase in dose efficiency, and thus, significantly less exposure time is needed to acquire images amenable to perfusion processing. This reduction in required irradiation time enables voxel-by-voxel perfusion maps to be generated on micro-CT scanners. Sample perfusion maps using a deconvolution-based perfusion analysis are included to demonstrate the improvement in image quality using the PICCS algorithm.

  6. A Flexible Method for Multi-Material Decomposition of Dual-Energy CT Images.

    PubMed

    Mendonca, Paulo R S; Lamb, Peter; Sahani, Dushyant V

    2014-01-01

    The ability of dual-energy computed-tomographic (CT) systems to determine the concentration of constituent materials in a mixture, known as material decomposition, is the basis for many of dual-energy CT's clinical applications. However, the complex composition of tissues and organs in the human body poses a challenge for many material decomposition methods, which assume the presence of only two, or at most three, materials in the mixture. We developed a flexible, model-based method that extends dual-energy CT's core material decomposition capability to handle more complex situations, in which it is necessary to disambiguate among and quantify the concentration of a larger number of materials. The proposed method, named multi-material decomposition (MMD), was used to develop two image analysis algorithms. The first was virtual unenhancement (VUE), which digitally removes the effect of contrast agents from contrast-enhanced dual-energy CT exams. VUE has the ability to reduce patient dose and improve clinical workflow, and can be used in a number of clinical applications such as CT urography and CT angiography. The second algorithm developed was liver-fat quantification (LFQ), which accurately quantifies the fat concentration in the liver from dual-energy CT exams. LFQ can form the basis of a clinical application targeting the diagnosis and treatment of fatty liver disease. Using image data collected from a cohort consisting of 50 patients and from phantoms, the application of MMD to VUE and LFQ yielded quantitatively accurate results when compared against gold standards. Furthermore, consistent results were obtained across all phases of imaging (contrast-free and contrast-enhanced). This is of particular importance since most clinical protocols for abdominal imaging with CT call for multi-phase imaging. We conclude that MMD can successfully form the basis of a number of dual-energy CT image analysis algorithms, and has the potential to improve the clinical utility

  7. SU-E-I-73: Clinical Evaluation of CT Image Reconstructed Using Interior Tomography

    SciTech Connect

    Zhang, J; Ge, G; Winkler, M; Cong, W; Wang, G

    2014-06-01

    Purpose: Radiation dose reduction has been a long standing challenge in CT imaging of obese patients. Recent advances in interior tomography (reconstruction of an interior region of interest (ROI) from line integrals associated with only paths through the ROI) promise to achieve significant radiation dose reduction without compromising image quality. This study is to investigate the application of this technique in CT imaging through evaluating imaging quality reconstructed from patient data. Methods: Projection data were directly obtained from patients who had CT examinations in a Dual Source CT scanner (DSCT). Two detectors in a DSCT acquired projection data simultaneously. One detector provided projection data for full field of view (FOV, 50 cm) while another detectors provided truncated projection data for a FOV of 26 cm. Full FOV CT images were reconstructed using both filtered back projection and iterative algorithm; while interior tomography algorithm was implemented to reconstruct ROI images. For comparison reason, FBP was also used to reconstruct ROI images. Reconstructed CT images were evaluated by radiologists and compared with images from CT scanner. Results: The results show that the reconstructed ROI image was in excellent agreement with the truth inside the ROI, obtained from images from CT scanner, and the detailed features in the ROI were quantitatively accurate. Radiologists evaluation shows that CT images reconstructed with interior tomography met diagnosis requirements. Radiation dose may be reduced up to 50% using interior tomography, depending on patient size. Conclusion: This study shows that interior tomography can be readily employed in CT imaging for radiation dose reduction. It may be especially useful in imaging obese patients, whose subcutaneous tissue is less clinically relevant but may significantly increase radiation dose.

  8. Micro-CT of rodents: state-of-the-art and future perspectives

    PubMed Central

    Clark, D. P.; Badea, C. T.

    2014-01-01

    Micron-scale computed tomography (micro-CT) is an essential tool for phenotyping and for elucidating diseases and their therapies. This work is focused on preclinical micro-CT imaging, reviewing relevant principles, technologies, and applications. Commonly, micro-CT provides high-resolution anatomic information, either on its own or in conjunction with lower-resolution functional imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). More recently, however, advanced applications of micro-CT produce functional information by translating clinical applications to model systems (e.g. measuring cardiac functional metrics) and by pioneering new ones (e.g. measuring tumor vascular permeability with nanoparticle contrast agents). The primary limitations of micro-CT imaging are the associated radiation dose and relatively poor soft tissue contrast. We review several image reconstruction strategies based on iterative, statistical, and gradient sparsity regularization, demonstrating that high image quality is achievable with low radiation dose given ever more powerful computational resources. We also review two contrast mechanisms under intense development. The first is spectral contrast for quantitative material discrimination in combination with passive or actively targeted nanoparticle contrast agents. The second is phase contrast which measures refraction in biological tissues for improved contrast and potentially reduced radiation dose relative to standard absorption imaging. These technological advancements promise to develop micro-CT into a commonplace, functional and even molecular imaging modality. PMID:24974176

  9. Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study

    SciTech Connect

    Juneja, Prabhjot; Harris, Emma J.; Kirby, Anna M.; Evans, Philip M.

    2012-11-01

    Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue segmentation

  10. Window classification of brain CT images in biomedical articles.

    PubMed

    Xue, Zhiyun; Antani, Sameer; Long, L Rodney; Demner-Fushman, Dina; Thoma, George R

    2012-01-01

    Effective capability to search biomedical articles based on visual properties of article images may significantly augment information retrieval in the future. In this paper, we present a new method to classify the window setting types of brain CT images. Windowing is a technique frequently used in the evaluation of CT scans, and is used to enhance contrast for the particular tissue or abnormality type being evaluated. In particular, it provides radiologists with an enhanced view of certain types of cranial abnormalities, such as the skull lesions and bone dysplasia which are usually examined using the " bone window" setting and illustrated in biomedical articles using "bone window images". Due to the inherent large variations of images among articles, it is important that the proposed method is robust. Our algorithm attained 90% accuracy in classifying images as bone window or non-bone window in a 210 image data set.

  11. 18F-FDG PET-CT Findings Before and After Laparoscopic Cryoablation of Small Renal Mass: An Initial Report

    PubMed Central

    Sivro, Ferida; van der Zee, Johan A.; Baars, Phillippe C.

    2015-01-01

    The aim of this study was to describe the characteristics of positron emission tomography (PET) molecular imaging combined with low-dose computed tomography (CT) in small renal mass (SRM) treated with cryoablation (CA). Currently, treatment success is defined by the absence of contrast enhancement at CT. However, the use of contrast is relatively contraindicated in patients with renal function impairment, mandating alternative follow-up strategies. Several reasons were identified as criteria for performing PET-CT before and/or after SRM-CA in 9 patients, and the results were retrospectively studied. The histology revealed renal cell carcinoma in 7 patients and oncocytoma in 2 patients. In 6 patients, a PET-CT was performed before and after CA. In one patient, the PET-CT was performed only before CA and in 2 patients only after CA. Before CA, clearly there was metabolic uptake of fluorine-18 fluorodeoxyglucose (18F-FDG) in the SRM in all patients. Following CA, the absence of 18F-FDG uptakes in the SRM could clearly be noticed. However, the tracer cannot always be distinguished from focal recurrence or reactive inflammatory tissue. In one patient, asymptomatic metastatic bone lesions were noticed when performing PET-CT at follow-up. This pilot study with 18F-FDG PET-CT for the follow-up of SRM cryosurgery showed that 18F-FDG PET-CT imaging could be used to characterize cryoablative tissue injury at different times after CA. PMID:28326272

  12. Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data

    NASA Astrophysics Data System (ADS)

    van der Bom, M. J.; Pluim, J. P. W.; Gounis, M. J.; van de Kraats, E. B.; Sprinkhuizen, S. M.; Timmer, J.; Homan, R.; Bartels, L. W.

    2011-02-01

    Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data is not a trivial task because of their fundamental difference in tissue contrast. This paper presents a technique that generates pseudo-computed tomography (CT) data from multi-spectral MRI acquisitions which is sufficiently similar to real CT data to enable registration of x-ray to MRI with comparable accuracy as registration of x-ray to CT. The method is based on a k-nearest-neighbors (kNN)-regression strategy which labels voxels of MRI data with CT Hounsfield Units. The regression method uses multi-spectral MRI intensities and intensity gradients as features to discriminate between various tissue types. The efficacy of using pseudo-CT data for registration of x-ray to MRI was tested on ex vivo animal data. 2D-3D registration experiments using CT and pseudo-CT data of multiple subjects were performed with a commonly used 2D-3D registration algorithm. On average, the median target registration error for registration of two x-ray images to MRI data was approximately 1 mm larger than for x-ray to CT registration. The authors have shown that pseudo-CT data generated from multi-spectral MRI facilitate registration of MRI to x-ray images. From the experiments it could be concluded that the accuracy achieved was comparable to that of registering x-ray images to CT data.

  13. Augmenting CT cardiac roadmaps with segmented streaming ultrasound

    NASA Astrophysics Data System (ADS)

    Duan, Qi; Shechter, Guy; Gutiérrez, Luis F.; Stanton, Douglas; Zagorchev, Lyubomir; Laine, Andrew F.; Elgort, Daniel R.

    2007-03-01

    Static X-ray computed tomography (CT) volumes are often used as anatomic roadmaps during catheter-based cardiac interventions performed under X-ray fluoroscopy guidance. These CT volumes provide a high-resolution depiction of soft-tissue structures, but at only a single point within the cardiac and respiratory cycles. Augmenting these static CT roadmaps with segmented myocardial borders extracted from live ultrasound (US) provides intra-operative access to real-time dynamic information about the cardiac anatomy. In this work, using a customized segmentation method based on a 3D active mesh, endocardial borders of the left ventricle were extracted from US image streams (4D data sets) at a frame rate of approximately 5 frames per second. The coordinate systems for CT and US modalities were registered using rigid body registration based on manually selected landmarks, and the segmented endocardial surfaces were overlaid onto the CT volume. The root-mean squared fiducial registration error was 3.80 mm. The accuracy of the segmentation was quantitatively evaluated in phantom and human volunteer studies via comparison with manual tracings on 9 randomly selected frames using a finite-element model (the US image resolutions of the phantom and volunteer data were 1.3 x 1.1 x 1.3 mm and 0.70 x 0.82 x 0.77 mm, respectively). This comparison yielded 3.70+/-2.5 mm (approximately 3 pixels) root-mean squared error (RMSE) in a phantom study and 2.58+/-1.58 mm (approximately 3 pixels) RMSE in a clinical study. The combination of static anatomical roadmap volumes and dynamic intra-operative anatomic information will enable better guidance and feedback for image-guided minimally invasive cardiac interventions.

  14. Dose calculation using megavoltage cone-beam CT

    SciTech Connect

    Morin, Olivier . E-mail: Morin@radonc17.ucsf.edu; Chen, Josephine; Aubin, Michele; Gillis, Amy; Aubry, Jean-Francois; Bose, Supratik; Chen Hong; Descovich, Martina; Xia Ping; Pouliot, Jean

    2007-03-15

    Purpose: To demonstrate the feasibility of performing dose calculation on megavoltage cone-beam CT (MVCBCT) of head-and-neck patients in order to track the dosimetric errors produced by anatomic changes. Methods and Materials: A simple geometric model was developed using a head-size water cylinder to correct an observed cupping artifact occurring with MVCBCT. The uniformity-corrected MVCBCT was calibrated for physical density. Beam arrangements and weights from the initial treatment plans defined using the conventional CT were applied to the MVCBCT image, and the dose distribution was recalculated. The dosimetric inaccuracies caused by the cupping artifact were evaluated on the water phantom images. An ideal test patient with no observable anatomic changes and a patient imaged with both CT and MVCBCT before and after considerable weight loss were used to clinically validate MVCBCT for dose calculation and to determine the dosimetric impact of large anatomic changes. Results: The nonuniformity of a head-size water phantom ({approx}30%) causes a dosimetric error of less than 5%. The uniformity correction method developed greatly reduces the cupping artifact, resulting in dosimetric inaccuracies of less than 1%. For the clinical cases, the agreement between the dose distributions calculated using MVCBCT and CT was better than 3% and 3 mm where all tissue was encompassed within the MVCBCT. Dose-volume histograms from the dose calculations on CT and MVCBCT were in excellent agreement. Conclusion: MVCBCT can be used to estimate the dosimetric impact of changing anatomy on several structures in the head-and-neck region.

  15. Dedicated Cone-Beam CT System for Extremity Imaging

    PubMed Central

    Al Muhit, Abdullah; Zbijewski, Wojciech; Thawait, Gaurav K.; Stayman, J. Webster; Packard, Nathan; Senn, Robert; Yang, Dong; Foos, David H.; Yorkston, John; Siewerdsen, Jeffrey H.

    2014-01-01

    Purpose To provide initial assessment of image quality and dose for a cone-beam computed tomographic (CT) scanner dedicated to extremity imaging. Materials and Methods A prototype cone-beam CT scanner has been developed for imaging the extremities, including the weight-bearing lower extremities. Initial technical assessment included evaluation of radiation dose measured as a function of kilovolt peak and tube output (in milliampere seconds), contrast resolution assessed in terms of the signal difference–to-noise ratio (SDNR), spatial resolution semiquantitatively assessed by using a line-pair module from a phantom, and qualitative evaluation of cadaver images for potential diagnostic value and image artifacts by an expert CT observer (musculoskeletal radiologist). Results The dose for a nominal scan protocol (80 kVp, 108 mAs) was 9 mGy (absolute dose measured at the center of a CT dose index phantom). SDNR was maximized with the 80-kVp scan technique, and contrast resolution was sufficient for visualization of muscle, fat, ligaments and/or tendons, cartilage joint space, and bone. Spatial resolution in the axial plane exceeded 15 line pairs per centimeter. Streaks associated with x-ray scatter (in thicker regions of the patient—eg, the knee), beam hardening (about cortical bone—eg, the femoral shaft), and cone-beam artifacts (at joint space surfaces oriented along the scanning plane—eg, the interphalangeal joints) presented a slight impediment to visualization. Cadaver images (elbow, hand, knee, and foot) demonstrated excellent visibility of bone detail and good soft-tissue visibility suitable to a broad spectrum of musculoskeletal indications. Conclusion A dedicated extremity cone-beam CT scanner capable of imaging upper and lower extremities (including weight-bearing examinations) provides sufficient image quality and favorable dose characteristics to warrant further evaluation for clinical use. © RSNA, 2013 Online supplemental material is available for

  16. Multi-material decomposition of spectral CT images

    NASA Astrophysics Data System (ADS)

    Mendonça, Paulo R. S.; Bhotika, Rahul; Maddah, Mahnaz; Thomsen, Brian; Dutta, Sandeep; Licato, Paul E.; Joshi, Mukta C.

    2010-04-01

    Spectral Computed Tomography (Spectral CT), and in particular fast kVp switching dual-energy computed tomography, is an imaging modality that extends the capabilities of conventional computed tomography (CT). Spectral CT enables the estimation of the full linear attenuation curve of the imaged subject at each voxel in the CT volume, instead of a scalar image in Hounsfield units. Because the space of linear attenuation curves in the energy ranges of medical applications can be accurately described through a two-dimensional manifold, this decomposition procedure would be, in principle, limited to two materials. This paper describes an algorithm that overcomes this limitation, allowing for the estimation of N-tuples of material-decomposed images. The algorithm works by assuming that the mixing of substances and tissue types in the human body has the physicochemical properties of an ideal solution, which yields a model for the density of the imaged material mix. Under this model the mass attenuation curve of each voxel in the image can be estimated, immediately resulting in a material-decomposed image triplet. Decomposition into an arbitrary number of pre-selected materials can be achieved by automatically selecting adequate triplets from an application-specific material library. The decomposition is expressed in terms of the volume fractions of each constituent material in the mix; this provides for a straightforward, physically meaningful interpretation of the data. One important application of this technique is in the digital removal of contrast agent from a dual-energy exam, producing a virtual nonenhanced image, as well as in the quantification of the concentration of contrast observed in a targeted region, thus providing an accurate measure of tissue perfusion.

  17. Patient-specific biomechanical model as whole-body CT image registration tool.

    PubMed

    Li, Mao; Miller, Karol; Joldes, Grand Roman; Doyle, Barry; Garlapati, Revanth Reddy; Kikinis, Ron; Wittek, Adam

    2015-05-01

    Whole-body computed tomography (CT) image registration is important for cancer diagnosis, therapy planning and treatment. Such registration requires accounting for large differences between source and target images caused by deformations of soft organs/tissues and articulated motion of skeletal structures. The registration algorithms relying solely on image processing methods exhibit deficiencies in accounting for such deformations and motion. We propose to predict the deformations and movements of body organs/tissues and skeletal structures for whole-body CT image registration using patient-specific non-linear biomechanical modelling. Unlike the conventional biomechanical modelling, our approach for building the biomechanical models does not require time-consuming segmentation of CT scans to divide the whole body into non-overlapping constituents with different material properties. Instead, a Fuzzy C-Means (FCM) algorithm is used for tissue classification to assign the constitutive properties automatically at integration points of the computation grid. We use only very simple segmentation of the spine when determining vertebrae displacements to define loading for biomechanical models. We demonstrate the feasibility and accuracy of our approach on CT images of seven patients suffering from cancer and aortic disease. The results confirm that accurate whole-body CT image registration can be achieved using a patient-specific non-linear biomechanical model constructed without time-consuming segmentation of the whole-body images.

  18. Dynamic CT imaging of volumetric changes in pulmonary nodules correlates with physical measurements of stiffness

    PubMed Central

    Lartey, Frederick M.; Rafat, Marjan; Negahdar, Mohammadreza; Malkovskiy, Andrey V.; Dong, Xinzhe; Sun, Xiaoli; Li, Mei; Doyle, Timothy; Rajadas, Jayakumar; Graves, Edward E.; Loo, Billy W.; Maxim, Peter G.

    2017-01-01

    Background and purpose A major challenge in CT screening for lung cancer is limited specificity when distinguishing between malignant and non-malignant pulmonary nodules (PN). Malignant nodules have different mechanical properties and tissue characteristics (‘stiffness’) from non-malignant nodules. This study seeks to improve CT specificity by demonstrating in rats that measurements of volumetric ratios in PNs with varying composition can be determined by respiratory-gated dynamic CT imaging and that these ratios correlate with direct physical measurements of PN stiffness. Methods and materials Respiratory-gated MicroCT images acquired at extreme tidal volumes of 9 rats with PNs from talc, matrigel and A549 human lung carcinoma were analyzed and their volumetric ratios (δ) derived. PN stiffness was determined by measuring the Young’s modulus using atomic force microscopy (AFM) for each nodule excised immediately after MicroCT imaging. Results There was significant correlation (p = 0.0002) between PN volumetric ratios determined by respiratory-gated CT imaging and the physical stiffness of the PNs determined from AFM measurements. Conclusion We demonstrated proof of concept that PN volume changes measured non-invasively correlate with direct physical measurements of stiffness. These results may translate clinically into a means of improving the specificity of CT screening for lung cancer and/or improving individual prognostic assessments based on lung tumor stiffness. PMID:27989402

  19. CT angiography after 20 years: a transformation in cardiovascular disease characterization continues to advance.

    PubMed

    Rubin, Geoffrey D; Leipsic, Jonathon; Joseph Schoepf, U; Fleischmann, Dominik; Napel, Sandy

    2014-06-01

    Through a marriage of spiral computed tomography (CT) and graphical volumetric image processing, CT angiography was born 20 years ago. Fueled by a series of technical innovations in CT and image processing, over the next 5-15 years, CT angiography toppled conventional angiography, the undisputed diagnostic reference standard for vascular disease for the prior 70 years, as the preferred modality for the diagnosis and characterization of most cardiovascular abnormalities. This review recounts the evolution of CT angiography from its development and early challenges to a maturing modality that has provided unique insights into cardiovascular disease characterization and management. Selected clinical challenges, which include acute aortic syndromes, peripheral vascular disease, aortic stent-graft and transcatheter aortic valve assessment, and coronary artery disease, are presented as contrasting examples of how CT angiography is changing our approach to cardiovascular disease diagnosis and management. Finally, the recently introduced capabilities for multispectral imaging, tissue perfusion imaging, and radiation dose reduction through iterative reconstruction are explored with consideration toward the continued refinement and advancement of CT angiography.

  20. Relationship between Hounsfield unit in CT scan and gray scale in CBCT

    NASA Astrophysics Data System (ADS)

    Kamaruddin, Noorshaida; Rajion, Zainul Ahmad; Yusof, Asilah; Aziz, Mohd Ezane

    2016-12-01

    Cone-beam computed tomography (CBCT) is an imaging system which has advantages over computed tomography (CT). Recently, CBCT has become widely used for oral and maxillofacial imaging. In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present (in vitro) study was to investigate the relationship between gray scale in CBCT and HU in CT scan. In this descriptive study, the anthropomorphic head phantom was scanned with CBCT and CT scanner. Gray scales and HUs were detected on images at the crown of the teeth, trabecular and cortical bone of mandible. The images were analyzed to obtain the gray scale value and HU value. The obtained value then used to investigate the relationship between CBCT gray scales and HUs. For the statistical analysis, t-test, Pearson's correlation and regression analysis were used. The differences between the gray scale of CBCT and HU of CT were statistically not significant, whereas the Pearson's correlation coefficients demonstrated a statistically significant correlation between gray scale of CBCT and HU of CT values. Considering the fact that gray scale in CBCT is important in pre assessment evaluation of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  1. Comparison of stroke infarction between CT perfusion and diffusion weighted imaging: preliminary results

    NASA Astrophysics Data System (ADS)

    Abd. Rahni, Ashrani Aizzuddin; Arka, Israna Hossain; Chellappan, Kalaivani; Mukari, Shahizon Azura; Law, Zhe Kang; Sahathevan, Ramesh

    2016-03-01

    In this paper we present preliminary results of comparison of automatic segmentations of the infarct core, between that obtained from CT perfusion (based on time to peak parameter) and diffusion weighted imaging (DWI). For each patient, the two imaging volumes were automatically co-registered to a common frame of reference based on an acquired CT angiography image. The accuracy of image registration is measured by the overlap of the segmented brain from both images (CT perfusion and DWI), measured within their common field of view. Due to the limitations of the study, DWI was acquired as a follow up scan up to a week after initial CT based imaging. However, we found significant overlap of the segmented brain (Jaccard indices of approximately 0.8) and the percentage of infarcted brain tissue from the two modalities were still fairly highly correlated (correlation coefficient of approximately 0.9). The results are promising with more data needed in future for clinical inference.

  2. Response of osteosarcoma to preoperative intravenous high-dose methotrexate chemotherapy: CT evaluation

    SciTech Connect

    Mail, J.T.; Cohen, M.D.; Mirkin, L.D.; Provisor, A.J.

    1985-01-01

    The histologic response of an osteosarcoma to preamputation high-dose methotrexate therapy can be used to determine the optimum maintenance chemotherapy regimen to be administered after amputation. This study evaluates computed tomography (CT) as a method of assessing the response of the tumor to the methotrexate therapy. Nine patients with nonmetastatic osteosarcoma of an extremity had a CT scan of the tumor at initial presentation. This was compared with a second CT scan after four courses of high-dose intravenous methotrexate. Each set of scans was evaluated for changes in bony destruction, soft-tissue mass, pattern of calcification, and extent of tumor involvement of the marrow cavity. These findings were correlated with the histologic response of the tumor as measured by the degree of tumor necrosis. The changes seen on CT correlated well with the degree of the histologic response in seven of the nine patients.

  3. Neck evaluation with barium-enhanced radiographs and CT scans after supraglottic subtotal laryngectomy.

    PubMed

    Niemeyer, J H; Balfe, D M; Hayden, R E

    1987-02-01

    Supraglottic subtotal laryngectomy (SSL) is a radical, yet voice-conserving, surgical procedure commonly performed for carcinoma of the supraglottic larynx. The pharyngograms and computed tomographic (CT) scans of 35 patients obtained after SSL were evaluated retrospectively. These examinations reliably demonstrated the changes in anatomy caused by removal of the epiglottis, aryepiglottic folds, and false vocal cords. Fourteen patients had documented recurrence of cancer; five mucosal, nine extramucosal. Three of five macroscopic mucosal recurrences in the larynx/pharynx were detected on the barium pharyngograms; the two mucosal lesions not seen were in the base of the tongue and tonsillar fossa. CT enabled detection of five of five recurrences and was superior to pharyngography in demonstrating the soft-tissue extent of disease. CT findings mimicking recurrence were seen in two patients: one with diffuse histiocytic lymphoma; the second, with benign hyperkeratosis. Barium and CT examinations are useful adjuncts to the clinical examination in detecting recurrent squamous cell carcinoma in patients following SSL.

  4. WE-G-207-07: Iterative CT Shading Correction Method with No Prior Information

    SciTech Connect

    Wu, P; Mao, T; Niu, T; Xie, S; Sheng, K

    2015-06-15

    Purpose: Shading artifacts are caused by scatter contamination, beam hardening effects and other non-ideal imaging condition. Our Purpose is to propose a novel and general correction framework to eliminate low-frequency shading artifacts in CT imaging (e.g., cone-beam CT, low-kVp CT) without relying on prior information. Methods: Our method applies general knowledge of the relatively uniform CT number distribution in one tissue component. Image segmentation is applied to construct template image where each structure is filled with the same CT number of that specific tissue. By subtracting the ideal template from CT image, the residual from various error sources are generated. Since the forward projection is an integration process, the non-continuous low-frequency shading artifacts in the image become continuous and low-frequency signals in the line integral. Residual image is thus forward projected and its line integral is filtered using Savitzky-Golay filter to estimate the error. A compensation map is reconstructed on the error using standard FDK algorithm and added to the original image to obtain the shading corrected one. Since the segmentation is not accurate on shaded CT image, the proposed scheme is iterated until the variation of residual image is minimized. Results: The proposed method is evaluated on a Catphan600 phantom, a pelvic patient and a CT angiography scan for carotid artery assessment. Compared to the one without correction, our method reduces the overall CT number error from >200 HU to be <35 HU and increases the spatial uniformity by a factor of 1.4. Conclusion: We propose an effective iterative algorithm for shading correction in CT imaging. Being different from existing algorithms, our method is only assisted by general anatomical and physical information in CT imaging without relying on prior knowledge. Our method is thus practical and attractive as a general solution to CT shading correction. This work is supported by the National Science

  5. Cervical tuberculous adenitis: CT manifestations

    SciTech Connect

    Reede, D.L.; Bergeron, R.T.

    1985-03-01

    Cervical tuberculous adenitis is being seen with increasing frequency in the United States; in the appropriate clinical setting it should be included in the differential diagnosis of an asymptomatic neck mass. Patients are typically young adults who are recent arrivals from Southeast Asia. A history of tuberculosis is not always elicited nor is the chest radiograph always abnormal. All of these patients have positive purified protein derivative tests unless they are anergic. The CT findings may lead to the diagnosis. Several CT patterns of nodal disease can be seen in tuberculous adenitis; some may mimic benign and neoplastic disease. The presence of a multiloculated or multichambered (conglomerate nodal) mass with central lucency and thick rims of enhancement and minimally effaced fascial planes is highly suggestive of tuberculous adenitis, especially if the patient has a strongly positive tuberculosis skin test.

  6. Ultra-low dose CT attenuation correction for PET/CT

    NASA Astrophysics Data System (ADS)

    Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

    2012-01-01

    A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging.

  7. Postmortem pulmonary CT in hypothermia.

    PubMed

    Schweitzer, Wolf; Thali, Michael; Giugni, Giannina; Winklhofer, Sebastian

    2014-12-01

    Fatal hypothermia has been associated with pulmonary edema. With postmortem full body computed tomography scanning (PMCT), the lungs can also be examined for CT attenuation. In fatal hypothermia cases low CT attenuation appeared to prevail in the lungs. We compared 14 cases of fatal hypothermia with an age-sex matched control group. Additionally, 4 cases of carbon monoxide (CO) poisoning were examined. Furthermore, 10 test cases were examined to test predictability based on PMCT. Two readers measured CT attenuation on four different axial slices across the lungs (blinded to case group and other reader's results). Hypothermia was associated with statistically significantly lower lung PMCT attenuation and lower lung weights than controls, and there was a dose-effect relationship at an environmental temperature cutoff of 2 °C. CO poisoning yielded low pulmonary attenuation but higher lung weights. General model based prediction yielded a 94% probability for fatal hypothermia deaths and a 21% probability for non-hypothermia deaths in the test group. Increased breathing rate is known to accompany both CO poisoning and hypothermia, so this could partly explain the low PMCT lung attenuation due to an oxygen dissociation curve left shift. A more marked distension in fatal hypothermia, compared to CO poisoning, indicates that further, possibly different mechanisms, are involved in these cases. Increased dead space and increased stiffness to deflation (but not inflation) appear to be effects of inhaling cold air (but not CO) that may explain the difference in low PMCT attenuation seen in hypothermia cases.

  8. CT-assisted agile manufacturing

    NASA Astrophysics Data System (ADS)

    Stanley, James H.; Yancey, Robert N.

    1996-11-01

    The next century will witness at least two great revolutions in the way goods are produced. First, workers will use the medium of virtual reality in all aspects of marketing, research, development, prototyping, manufacturing, sales and service. Second, market forces will drive manufacturing towards small-lot production and just-in-time delivery. Already, we can discern the merging of these megatrends into what some are calling agile manufacturing. Under this new paradigm, parts and processes will be designed and engineered within the mind of a computer, tooled and manufactured by the offspring of today's rapid prototyping equipment, and evaluated for performance and reliability by advanced nondestructive evaluation (NDE) techniques and sophisticated computational models. Computed tomography (CT) is the premier example of an NDE method suitable for future agile manufacturing activities. It is the only modality that provides convenient access to the full suite of engineering data that users will need to avail themselves of computer- aided design, computer-aided manufacturing, and computer- aided engineering capabilities, as well as newly emerging reverse engineering, rapid prototyping and solid freeform fabrication technologies. As such, CT is assured a central, utilitarian role in future industrial operations. An overview of this exciting future for industrial CT is presented.

  9. Lesion area detection using source image correlation coefficient for CT perfusion imaging.

    PubMed

    Fan Zhu; Rodriguez Gonzalez, David; Carpenter, Trevor; Atkinson, Malcolm; Wardlaw, Joanna

    2013-09-01

    Computer tomography (CT) perfusion imaging is widely used to calculate brain hemodynamic quantities such as cerebral blood flow, cerebral blood volume, and mean transit time that aid the diagnosis of acute stroke. Since perfusion source images contain more information than hemodynamic maps, good utilization of the source images can lead to better understanding than the hemodynamic maps alone. Correlation-coefficient tests are used in our approach to measure the similarity between healthy tissue time-concentration curves and unknown curves. This information is then used to differentiate penumbra and dead tissues from healthy tissues. The goal of the segmentation is to fully utilize information in the perfusion source images. Our method directly identifies suspected abnormal areas from perfusion source images and then delivers a suggested segmentation of healthy, penumbra, and dead tissue. This approach is designed to handle CT perfusion images, but it can also be used to detect lesion areas in magnetic resonance perfusion images.

  10. Exploring miniature insect brains using micro-CT scanning techniques

    PubMed Central

    Smith, Dylan B.; Bernhardt, Galina; Raine, Nigel E.; Abel, Richard L.; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J.

    2016-01-01

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures. PMID:26908205

  11. Exploring miniature insect brains using micro-CT scanning techniques.

    PubMed

    Smith, Dylan B; Bernhardt, Galina; Raine, Nigel E; Abel, Richard L; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J

    2016-02-24

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures.

  12. SU-E-J-72: Dosimetric Study of Cone-Beam CT-Based Radiation Treatment Planning Using a Patient-Specific Stepwise CT-Density Table

    SciTech Connect

    Chen, S; Le, Q; Mutaf, Y; Yi, B; D’Souza, W

    2015-06-15

    Purpose: To assess dose calculation accuracy of cone-beam CT (CBCT) based treatment plans using a patient-specific stepwise CT-density conversion table in comparison to conventional CT-based treatment plans. Methods: Unlike CT-based treatment planning which use fixed CT-density table, this study used patient-specific CT-density table to minimize the errors in reconstructed mass densities due to the effects of CBCT Hounsfield unit (HU) uncertainties. The patient-specific CT-density table was a stepwise function which maps HUs to only 6 classes of materials with different mass densities: air (0.00121g/cm3), lung (0.26g/cm3), adipose (0.95g/cm3), tissue (1.05 g/cm3), cartilage/bone (1.6g/cm3), and other (3g/cm3). HU thresholds to define different materials were adjusted for each CBCT via best match with the known tissue types in these images. Dose distributions were compared between CT-based plans and CBCT-based plans (IMRT/VMAT) for four types of treatment sites: head and neck (HN), lung, pancreas, and pelvis. For dosimetric comparison, PTV mean dose in both plans were compared. A gamma analysis was also performed to directly compare dosimetry in the two plans. Results: Compared to CT-based plans, the differences for PTV mean dose were 0.1% for pelvis, 1.1% for pancreas, 1.8% for lung, and −2.5% for HN in CBCT-based plans. The gamma passing rate was 99.8% for pelvis, 99.6% for pancreas, and 99.3% for lung with 3%/3mm criteria, and 80.5% for head and neck with 5%/3mm criteria. Different dosimetry accuracy level was observed: 1% for pelvis, 3% for lung and pancreas, and 5% for head and neck. Conclusion: By converting CBCT data to 6 classes of materials for dose calculation, 3% of dose calculation accuracy can be achieved for anatomical sites studied here, except HN which had a 5% accuracy. CBCT-based treatment planning using a patient-specific stepwise CT-density table can facilitate the evaluation of dosimetry changes resulting from variation in patient anatomy.

  13. Micro-CT vs. Whole Body Multirow Detector CT for Analysing Bone Regeneration in an Animal Model

    PubMed Central

    Bissinger, Oliver; Kirschke, Jan S.; Probst, Florian Andreas; Stauber, Martin; Wolff, Klaus-Dietrich; Haller, Bernhard; Götz, Carolin; Plank, Christian; Kolk, Andreas

    2016-01-01

    Objectives Compared with multirow detector CT (MDCT), specimen (ex vivo) micro-CTCT) has a significantly higher (~ 30 x) spatial resolution and is considered the gold standard for assessing bone above the cellular level. However, it is expensive and time-consuming, and when applied in vivo, the radiation dose accumulates considerably. The aim of this study was to examine whether the lower resolution of the widely used MDCT is sufficient to qualitatively and quantitatively evaluate bone regeneration in rats. Methods Forty critical-size defects (5mm) were placed in the mandibular angle of rats and covered with coated bioactive titanium implants to promote bone healing. Five time points were selected (7, 14, 28, 56 and 112 days). μCT and MDCT were used to evaluate the defect region to determine the bone volume (BV), tissue mineral density (TMD) and bone mineral content (BMC). Results MDCT constantly achieved higher BV values than μCT (10.73±7.84 mm3 vs. 6.62±4.96 mm3, p<0.0001) and consistently lower TMD values (547.68±163.83 mm3 vs. 876.18±121.21 mm3, p<0.0001). No relevant difference was obtained for BMC (6.48±5.71 mm3 vs. 6.15±5.21 mm3, p = 0.40). BV and BMC showed very strong correlations between both methods, whereas TMD was only moderately correlated (r = 0.87, r = 0.90, r = 0.68, p < 0.0001). Conclusions Due to partial volume effects, MDCT overestimated BV and underestimated TMD but accurately determined BMC, even in small volumes, compared with μCT. Therefore, if bone quantity is a sufficient end point, a considerable number of animals and costs can be saved, and compared with in vivo μCT, the required dose of radiation can be reduced. PMID:27880788

  14. Mixed connective tissue disorder and Castleman's disease.

    PubMed

    Chrispal, Anugrah; Vasuki, Zoya; Thomas, Elsa Mary; Boorugu, Hari Kishan

    2010-08-01

    We present a 16-year-old girl who presented with polyarthritis in association with Raynaud's phenomenon, malar rash, oral ulcers, photosensitivity and alopecia of 6 months duration. On evaluation, it emerged that she had a mixed connective tissue disorder with a mesangio-proliferative glomerulonephritis. Her Chest radiograph revealed a well defined left mid and lower zone opacity with evidence of a hilar mass on CT Thorax. Histopathological examination following CT guided biopsy of the mass revealed a hyaline vascular type of Castleman's disease. Mixed Connective Tissue Disorder with Castleman's Disease is a rare association; the patient presenting with varied and interesting manifestations. It is important to understand this association in view of management. The exact etio-pathogenesis of the autoimmune manifestations in patients with Castleman's disease is not clear. Treatment with immunosuppression can suppress both immune manifestations and result in tumour regression as well.

  15. Role of CT Imaging with Volume Reconstruction in Hemi Facial Hypertrophy: A Pediatric Case Report.

    PubMed

    I, Gurubharath; Karanam, Lakshmi Sudha Prasanna; P, Ramesh

    2014-06-01

    Hemifacial hypertrophy is a rare congenital disorder more common in males.It involves the soft tissue, hard bones and teeth of the face.Its etiology is unknown and multiple theories have been postulated. We present a 6-year-old male with hemifacial hypertrophy and describes the importance of CT volume reconstruction in this condition.

  16. CT of 338 active professional boxers.

    PubMed

    Jordan, B D; Jahre, C; Hauser, W A; Zimmerman, R D; Zarrelli, M; Lipsitz, E C; Johnson, V; Warren, R F; Tsairis, P; Folk, F S

    1992-11-01

    Computed tomography (CT) was performed in 338 active professional boxers. CT scans were abnormal in 25 boxers (7%). The most common CT abnormality was brain atrophy (22 cases). Focal lesions of low attenuation consistent with posttraumatic encephalomalacia were noted in only three boxers. Boxers with abnormal CT scans did not differ from those with borderline or normal CT scans in regard to age, win-loss record, number of bouts, or history of an abnormal electroencephalogram. Thirty-seven boxers with borderline CT scans (49%) and 17 with abnormal CT scans (68%) reported a previous technical knockout (TKO) or knockout (KO), compared with only 89 (37%) of the 238 boxers with normal CT scans (P < .01). Brain atrophy was noted more frequently in boxers with a large cavum septum pellucidum (CSP) than in those with a small or no CSP (P < .05). Boxers with abnormal or borderline CT scans who experienced a TKO or KO were slightly older than those with normal CT scans and a history of a TKO or KO (P < .05).

  17. Modern CT applications in veterinary medicine.

    PubMed

    Garland, Melissa R; Lawler, Leo P; Whitaker, Brent R; Walker, Ian D F; Corl, Frank M; Fishman, Elliot K

    2002-01-01

    Although computed tomography (CT) is used primarily for diagnosis in humans, it can also be used to diagnose disease in veterinary patients. CT and associated three-dimensional reconstruction have a role in diagnosis of a range of illnesses in a variety of animals. In a sea turtle with failure to thrive, CT showed a nodal mass in the chest, granulomas in the lungs, and a ball in the stomach. CT of a sea dragon with balance and movement problems showed absence of the swim bladder. In a sloth with failure to thrive, CT allowed diagnosis of a coin in the intestine. CT of a puffin with failure to thrive showed a mass in the chest, which was found to be a hematoma. In a smooth-sided toad whose head was tilted to one side and who was circling in that direction, CT showed partial destruction of the temporal bone. CT of a domestic cat with listlessness showed a mass with focal calcification, which proved to be a leiomyosarcoma. CT of a sea otter showed pectus excavatum, which is caused by the animal smashing oysters against its chest. In a Japanese koi with abdominal swelling, CT allowed diagnosis of a hepatoma.

  18. Qualitative and Quantitative Imaging Evaluation of Renal Cell Carcinoma Subtypes with Grating-based X-ray Phase-contrast CT

    PubMed Central

    Braunagel, Margarita; Birnbacher, Lorenz; Willner, Marian; Marschner, Mathias; De Marco, Fabio; Viermetz, Manuel; Notohamiprodjo, Susan; Hellbach, Katharina; Auweter, Sigrid; Link, Vera; Woischke, Christine; Reiser, Maximilian F.; Pfeiffer, Franz; Notohamiprodjo, Mike; Herzen, Julia

    2017-01-01

    Current clinical imaging methods face limitations in the detection and correct characterization of different subtypes of renal cell carcinoma (RCC), while these are important for therapy and prognosis. The present study evaluates the potential of grating-based X-ray phase-contrast computed tomography (gbPC-CT) for visualization and characterization of human RCC subtypes. The imaging results for 23 ex vivo formalin-fixed human kidney specimens obtained with phase-contrast CT were compared to the results of the absorption-based CT (gbCT), clinical CT and a 3T MRI and validated using histology. Regions of interest were placed on each specimen for quantitative evaluation. Qualitative and quantitative gbPC-CT imaging could significantly discriminate between normal kidney cortex (54 ± 4 HUp) and clear cell (42 ± 10), papillary (43 ± 6) and chromophobe RCCs (39 ± 7), p < 0.05 respectively. The sensitivity for detection of tumor areas was 100%, 50% and 40% for gbPC-CT, gbCT and clinical CT, respectively. RCC architecture like fibrous strands, pseudocapsules, necrosis or hyalinization was depicted clearly in gbPC-CT and was not equally well visualized in gbCT, clinical CT and MRI. The results show that gbPC-CT enables improved discrimination of normal kidney parenchyma and tumorous tissues as well as different soft-tissue components of RCCs without the use of contrast media. PMID:28361951

  19. X-ray Phase Contrast Imaging of Calcified Tissue and Biomaterial Structure in Bioreactor Engineered Tissues

    SciTech Connect

    Appel, Alyssa A.; Larson, Jeffery C.; Garson, III, Alfred B.; Guan, Huifeng; Zhong, Zhong; Nguyen, Bao-Ngoc; Fisher, John P.; Anastasio, Mark A.; Brey, Eric M.

    2014-11-04

    Tissues engineered in bioreactor systems have been used clinically to replace damaged tissues and organs. In addition, these systems are under continued development for many tissue engineering applications. The ability to quantitatively assess material structure and tissue formation is critical for evaluating bioreactor efficacy and for preimplantation assessment of tissue quality. These techniques allow for the nondestructive and longitudinal monitoring of large engineered tissues within the bioreactor systems and will be essential for the translation of these strategies to viable clinical therapies. X-ray Phase Contrast (XPC) imaging techniques have shown tremendous promise for a number of biomedical applications owing to their ability to provide image contrast based on multiple X-ray properties, including absorption, refraction, and scatter. In this research, mesenchymal stem cell-seeded alginate hydrogels were prepared and cultured under osteogenic conditions in a perfusion bioreactor. The constructs were imaged at various time points using XPC microcomputed tomography (µCT). Imaging was performed with systems using both synchrotron- and tube-based X-ray sources. XPC µCT allowed for simultaneous three-dimensional (3D) quantification of hydrogel size and mineralization, as well as spatial information on hydrogel structure and mineralization. Samples were processed for histological evaluation and XPC showed similar features to histology and quantitative analysis consistent with the histomorphometry. Furthermore, these results provide evidence of the significant potential of techniques based on XPC for noninvasive 3D imaging engineered tissues grown in bioreactors.

  20. A case of catastrophic antiphospholipid syndrome, which presented an acute interstitial pneumonia-like image on chest CT scan.

    PubMed

    Kameda, Tomohiro; Dobashi, Hiroaki; Susaki, Kentaro; Danjo, Junichi; Nakashima, Shusaku; Shimada, Hiromi; Izumikawa, Miharu; Takeuchi, Yohei; Mitsunaka, Hiroki; Bandoh, Shuji; Imataki, Osamu; Nose, Masato; Matsunaga, Takuya

    2015-01-01

    We report the case of catastrophic antiphospholipid syndrome (CAPS) complicated with mixed connective tissue disease (MCTD). A female patient was diagnosed with acute interstitial pneumonia (AIP) with MCTD by chest CT scan. Corticosteroid therapy was refractory for lung involvement, and she died due to acute respiratory failure. The autopsy revealed that AIP was compatible with lung involvement of CAPS. We therefore suggest that chest CT might reveal AIP-like findings in CAPS patients whose condition is complicated with pulmonary manifestations.

  1. Tissue irradiator

    DOEpatents

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-12-16

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in- vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood- carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170.

  2. Ultra-filtration measurement using CT imaging technology

    NASA Astrophysics Data System (ADS)

    Lu, Junfeng; Lu, Wenqiang

    2009-02-01

    As a functional unit in the hemodialysis process, dialyzer captured quite a few medical research interests since 1980s. In the design of dialyzer or in the ongoing hemodialysis process, to estimate the ultra-filtration amount of a dialyzer, the sideway loss of the running blood flow through hollow fibers or filtration channels should be measured. This further leads to the measurement of the blood flow inside the dialyzer. For this measurement, a non-invasive method is highly desired because of the high-dense bundled hollow fibers or packed channels inside the dialyzer. As non-invasive measurement tools, CT (Computed Tomography) technologies were widely used for tissue, bone, and cancerous clinical analyses etc …. Thus, in this paper, a CT system is adopted to predict the blood flow inside a hollow fiber dialyzer. In view of symmetric property of the hollow fiber dialyzer, the largest cutting plane that parallels to the cylindrical dialyzer was analyzed by the CT system dynamically. And then, a noninvasive image analysis method used to predict the ultra-filtration amount is proposed.

  3. CT and radiographic appearance of extracranial Onyx(®) embolization.

    PubMed

    Jia, J B; Green, C S; Cohen, A J; Helmy, M

    2015-03-01

    Onyx(®) (ev3, Irvine, CA, USA) is a liquid embolic agent composed of ethylene vinyl alcohol copolymer dissolved in dimethyl sulphoxide used for the treatment of intracranial arteriovenous malformations. Onyx is a preferred embolizing agent due to its unique properties, non-adhesive nature, and durability. In addition to its approved intracranial application, Onyx is also being used successfully in extracranial embolization in areas including extracranial aneurisms and vascular malformations, trauma, gastrointestinal bleeding, and neoplasms. Because of its increasing utilization, it is important for reporting radiologists to be able to recognize its extracranial appearance across different imaging techniques and to be familiar with its uses. The goal of this review is to describe the extracranial uses of Onyx and its appearance in various extracranial locations at radiography and CT, while providing didactic examples. Onyx appears radiodense at CT and plain radiography and has a curvilinear pattern following the expected path of the vessel embolized. At CT, Onyx creates streak artefact that may obstruct the view of surrounding tissues consistent with descriptions of other tantalum devices.

  4. Functional Imaging: CT and MRI

    PubMed Central

    van Beek, Edwin JR; Hoffman, Eric A

    2008-01-01

    Synopsis Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled MDCT allow for quantification of presence and distribution of parenchymal and airway pathology, Xenon gas can be employed to assess regional ventilation of the lungs and rapid bolus injections of iodinated contrast agent can provide quantitative measure of regional parenchymal perfusion. Advances in magnetic resonance imaging (MRI) of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized helium imaging, which can allow imaging of pulmonary ventilation and .measurement of the size of emphysematous spaces. PMID:18267192

  5. Corticosteroid Responsive Sarcoidosis with Multisystemic Involvement Years after Initial Diagnosis: A Lymphoma Mimicker on 18-FDG PET/CT

    PubMed Central

    Acar, Turker; Savas, Recep; Kocacelebi, Kenan; Ucan, Eyup Sabri

    2015-01-01

    Sarcoidosis is a chronic multisystemic inflammatory disease characterized by noncaseating epithelioid cell granulomas. 18-Fluorodeoxyglucose positron-emission tomography/computer tomography (FDG-PET/CT) is increasingly used in routine clinical practice to assess active sarcoidosis because it can detect active inflammatory granulomatous disease. However, active sarcoidosis lesions are observed to be hypermetabolic on FDG-PET/CT much like malignancies, which may lead to misinterpretation on imaging. In this case report, we present a rare case of sarcoidosis with multisystem involvement including lung, lymph nodes, bone, pleura, and soft tissue that mimicked lymphoma on FDG-PET/CT and responded to corticosteroid treatment. PMID:26312138

  6. Cortical Tremor (CT) with coincident orthostatic movements.

    PubMed

    Termsarasab, Pichet; Frucht, Steven J

    2015-01-01

    Cortical tremor (CT) is a form of cortical reflex myoclonus that can mimic essential tremor (ET). Clinical features that are helpful in distinguishing CT from ET are the irregular and jerky appearance of the movements. We report two patients with CT with coexisting orthostatic movements, either orthostatic tremor (OT) or myoclonus, who experienced functional improvement in both cortical myoclonus and orthostatic movements when treated with levetiracetam.

  7. Pediatric CT and radiation: our responsibility

    NASA Astrophysics Data System (ADS)

    Frush, Donald P.

    2009-02-01

    In order to discuss the cost-benefit ratio of CT examinations in children, one must be familiar with the reasons why CT can provide a high collective or individual dose. The reasons include increasing CT use as well as lack of attention to dose reduction strategies. While those have been substantial efforts for dose reduction, additional work is necessary to prevent unnecessary radiation exposure. This responsibility is shared between science and medicine, industry, regulatory agencies, and patients as well.

  8. Radiation dose measurements in coronary CT angiography

    PubMed Central

    Sabarudin, Akmal; Sun, Zhonghua

    2013-01-01

    Coronary computed tomography (CT) angiography is associated with high radiation dose and this has raised serious concerns in the literature. Awareness of various parameters for dose estimates and measurements of coronary CT angiography plays an important role in increasing our understanding of the radiation exposure to patients, thus, contributing to the implementation of dose-saving strategies. This article provides an overview of the radiation dose quantity and its measurement during coronary CT angiography procedures. PMID:24392190

  9. Normal conus medullaris: CT criteria for recognition

    SciTech Connect

    Grogan, J.P.; Daniels, D.L.; Williams, I.L.; Rauschning, W.; Haughton, V.M.

    1984-06-01

    The normal CT configuration and dimension of the conus medullaris and adjacent spinal cord were determined in 30 patients who had no clinical evidence of conus compression. CT studies were also correlated with anatomic sections in cadavers. The normal conus on CT has a distinctive oval configuration, an arterior sulcus, and a posterior promontory. The anteroposterior diameter ranged from 5 to 8 mm; the transverse diameter from 8 to 11 mm. Intramedullary processes altered both the dimensions and configuration of the conus.

  10. A registration-based segmentation method with application to adiposity analysis of mice microCT images

    NASA Astrophysics Data System (ADS)

    Bai, Bing; Joshi, Anand; Brandhorst, Sebastian; Longo, Valter D.; Conti, Peter S.; Leahy, Richard M.

    2014-04-01

    Obesity is a global health problem, particularly in the U.S. where one third of adults are obese. A reliable and accurate method of quantifying obesity is necessary. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) are two measures of obesity that reflect different associated health risks, but accurate measurements in humans or rodent models are difficult. In this paper we present an automatic, registration-based segmentation method for mouse adiposity studies using microCT images. We co-register the subject CT image and a mouse CT atlas. Our method is based on surface matching of the microCT image and an atlas. Surface-based elastic volume warping is used to match the internal anatomy. We acquired a whole body scan of a C57BL6/J mouse injected with contrast agent using microCT and created a whole body mouse atlas by manually delineate the boundaries of the mouse and major organs. For method verification we scanned a C57BL6/J mouse from the base of the skull to the distal tibia. We registered the obtained mouse CT image to our atlas. Preliminary results show that we can warp the atlas image to match the posture and shape of the subject CT image, which has significant differences from the atlas. We plan to use this software tool in longitudinal obesity studies using mouse models.

  11. Temporal subtraction contrast-enhanced dedicated breast CT

    NASA Astrophysics Data System (ADS)

    Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.

    2016-09-01

    The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0-16%), NCC (0-6%), NMI (0-13%) and TRE (0-34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was

  12. Dosimetric impact of image artifact from a wide-bore CT scanner in radiotherapy treatment planning

    SciTech Connect

    Wu, Vincent; Podgorsak, Matthew B.; Tran, Tuan-Anh; Malhotra, Harish K.; Wang, Iris Z.

    2011-07-15

    Purpose: Traditional computed tomography (CT) units provide a maximum scan field-of-view (sFOV) diameter of 50 cm and a limited bore size, which cannot accommodate a large patient habitus or an extended simulation setup in radiation therapy (RT). Wide-bore CT scanners with increased bore size were developed to address these needs. Some scanners have the capacity to reconstruct the CT images at an extended FOV (eFOV), through data interpolation or extrapolation, using projection data acquired with a conventional sFOV. Objects that extend past the sFOV for eFOV reconstruction may generate image artifacts resulting from truncated projection data; this may distort CT numbers and structure contours in the region beyond the sFOV. The purpose of this study was to evaluate the dosimetric impact of image artifacts from eFOV reconstruction with a wide-bore CT scanner in radiotherapy (RT) treatment planning. Methods: Testing phantoms (i.e., a mini CT phantom with equivalent tissue inserts, a set of CT normal phantoms and anthropomorphic phantoms of the thorax and the pelvis) were used to evaluate eFOV artifacts. Reference baseline images of these phantoms were acquired with the phantom centrally positioned within the sFOV. For comparison, the phantoms were then shifted laterally and scanned partially outside the sFOV, but still within the eFOV. Treatment plans were generated for the thoracic and pelvic anthropomorphic phantoms utilizing the Eclipse treatment planning system (TPS) to study the potential effects of eFOV artifacts on dose calculations. All dose calculations of baseline and test treatment plans were carried out using the same MU. Results: Results show that both body contour and CT numbers are altered by image artifacts in eFOV reconstruction. CT number distortions of up to -356 HU for bone tissue and up to 323 HU for lung tissue were observed in the mini CT phantom. Results from the large body normal phantom, which is close to a clinical patient size, show

  13. False-positive FDG PET uptake--the role of PET/CT.

    PubMed

    Rosenbaum, Sandra J; Lind, Thomas; Antoch, Gerald; Bockisch, Andreas

    2006-05-01

    Positron emission tomography (PET) is a powerful molecular imaging technique for the human body-imaging applications currently available. As altered glucose metabolism is characteristic for many malignancies, FDG-PET is mostly used in oncology for staging and therapy control. Although PET is a sensitive tool for detecting malignancy, FDG uptake is not tumor specific. It can also be seen in healthy tissue or in benign disease as inflammation or posttraumatic repair and could be mistaken for cancer. The experienced nuclear medicine physician mostly manages to differentiate malignant from non-malignant FDG uptake, but some findings may remain ambiguous. In these cases, the difficulties in differentiating physiologic variants or benign causes of FDG uptake from tumor tissue can often be overcome by combined PET and CT (PET/CT) as anatomic information is added to the metabolic data. Thus, PET/CT improves the diagnostic accuracy compared to PET alone and helps to avoid unnecessary surgery/therapy. However, PET/CT involves other sources of artifacts that may occur when using CT for attenuation correction of PET or by patient motion caused by respiration or bowel movements.

  14. Intracranial CT angiography obtained from a cerebral CT perfusion examination

    SciTech Connect

    Gratama van Andel, H. A. F.; Venema, H. W.; Majoie, C. B.; Den Heeten, G. J.; Grimbergen, C. A.; Streekstra, G. J.

    2009-04-15

    CT perfusion (CTP) examinations of the brain are performed increasingly for the evaluation of cerebral blood flow in patients with stroke and vasospasm after subarachnoid hemorrhage. Of the same patient often also a CT angiography (CTA) examination is performed. This study investigates the possibility to obtain CTA images from the CTP examination, thereby possibly obviating the CTA examination. This would save the patient exposure to radiation, contrast, and time. Each CTP frame is a CTA image with a varying amount of contrast enhancement and with high noise. To improve the contrast-to-noise ratio (CNR) we combined all 3D images into one 3D image after registration to correct for patient motion between time frames. Image combination consists of weighted averaging in which the weighting factor of each frame is proportional to the arterial contrast. It can be shown that the arterial CNR is maximized in this procedure. An additional advantage of the use of the time series of CTP images is that automatic differentiation between arteries and veins is possible. This feature was used to mask veins in the resulting 3D images to enhance visibility of arteries in maximum intensity projection (MIP) images. With a Philips Brilliance 64 CT scanner (64x0.625 mm) CTP examinations of eight patients were performed on 80 mm of brain using the toggling table technique. The CTP examination consisted of a time series of 15 3D images (2x64x0.625 mm; 80 kV; 150 mAs each) with an interval of 4 s. The authors measured the CNR in images obtained with weighted averaging, images obtained with plain averaging, and images with maximal arterial enhancement. The authors also compared CNR and quality of the images with that of regular CTA examinations and examined the effectiveness of automatic vein masking in MIP images. The CNR of the weighted averaged images is, on the average, 1.73 times the CNR of an image at maximal arterial enhancement in the CTP series, where the use of plain averaging

  15. Reconstruction filters and contrast detail curves in CT

    NASA Astrophysics Data System (ADS)

    Huda, W.; Ogden, K. M.; Samei, E.; Scalzetti, E. M.; Lavallee, R. L.; Roskopf, M. L.; Groat, G. E.

    2008-03-01

    In this study, we investigated the effect of CT reconstruction filters in abdominal CT images of a male anthropomorphic phantom. A GE Light Speed CT 4-slice scanner was used to scan the abdomen of an adult Rando phantom. Cross sectional images of the phantom were reconstructed using four reconstruction filters: (1) soft tissue with the lowest noise; (2) detail (relative noise 1.7); (3) bone (relative noise 4.5); and (4) edge (relative noise 7.7). A two Alternate Forced Choice (AFC) experimental paradigm was used to estimate the intensity needed to achieve 92% correct (i.e., I 92%). Four observers measured detection performance for five lesions with size ranging from 2.5 to 12.5 mm for each of these four reconstruction filters. Contrast detail curves obtained in images of an anthropomorphic phantom were not straight lines, but best fitted to a second order polynomial. Results from four readers show similar trends with modest inter-observer differences with the measured coefficient of variation of the absolute performance levels of ~22%. All reconstruction filters had similar shaped contrast detail curves except for smallest details where the frequency response of filters differed most significantly. Increasing the noise level always reduced detection performance, and a doubling of image noise resulted in an average drop in detection performance of ~20%. The key findings of this study are that (a) the Rose model can provide reasonable predictions as to how changes in lesion size affect observer detection; (b) the shape of CT contrast detail curves is affected only very slightly with reconstruction filter; (c) changes in reconstruction filter noise can predict qualitative changes in observer detection performance, but are poor direct predictors of the quantitative changes of imaging performance.

  16. Temperature Measurements of the Low-Attenuation Radiographic Ice Ball During CT-Guided Renal Cryoablation

    SciTech Connect

    Permpongkosol, Sompol; Link, Richard E.; Kavoussi, Louis R.; Solomon, Stephen B.

    2008-01-15

    During renal cryoablation a low-attenuation area on CT develops around the cryoprobe. Knowledge of the temperature of the growing low-attenuation area can guide therapy and ensure lethal temperatures. Herein, we report thermocouple results and correlating CT images during the development of the low-attenuation 'radiographic ice ball.' Five patients who underwent percutaneous CT-guided renal cryoablation were identified who had thermocouples inserted and serial intraprocedural CT images that included images with thermocouple measurements of 0{sup o} and sub-0{sup o}C. Thermocouples had been percutaneously placed just beyond the edge of the tumors either to ensure adequate cooling or to ensure safety to adjacent critical structures. Renal cryotherapy under CT guidance produced a growing low-attenuation area corresponding to the radiographic ice ball. When the thermocouple measured 0{sup o}C, CT images showed the thermocouple tip at the edge of the low-attenuation ice ball. At lower temperatures the tip was within the low-attenuation ice ball. We conclude that knowledge of the temperature at the ice ball edge during cryoablation can be used to predict the extent of tissue necrosis and thus provide an estimate of cryotherapy effectiveness during the procedure. Further work is necessary to establish a firm relationship between the thermal conditions and the zone of damage.

  17. Temperature measurements of the low-attenuation radiographic ice ball during CT-guided renal cryoablation.

    PubMed

    Permpongkosol, Sompol; Link, Richard E; Kavoussi, Louis R; Solomon, Stephen B

    2008-01-01

    During renal cryoablation a low-attenuation area on CT develops around the cryoprobe. Knowledge of the temperature of the growing low-attenuation area can guide therapy and ensure lethal temperatures. Herein, we report thermocouple results and correlating CT images during the development of the low-attenuation "radiographic ice ball." Five patients who underwent percutaneous CT-guided renal cryoablation were identified who had thermocouples inserted and serial intraprocedural CT images that included images with thermocouple measurements of 0 degrees and sub-0 degrees C. Thermocouples had been percutaneously placed just beyond the edge of the tumors either to ensure adequate cooling or to ensure safety to adjacent critical structures. Renal cryotherapy under CT guidance produced a growing low-attenuation area corresponding to the radiographic ice ball. When the thermocouple measured 0 degrees C, CT images showed the thermocouple tip at the edge of the low-attenuation ice ball. At lower temperatures the tip was within the low-attenuation ice ball. We conclude that knowledge of the temperature at the ice ball edge during cryoablation can be used to predict the extent of tissue necrosis and thus provide an estimate of cryotherapy effectiveness during the procedure. Further work is necessary to establish a firm relationship between the thermal conditions and the zone of damage.

  18. Relationship between Hounsfield Unit in CT Scan and Gray Scale in CBCT.

    PubMed

    Razi, Tahmineh; Niknami, Mahdi; Alavi Ghazani, Fakhri

    2014-01-01

    Background and aims. Cone-beam computed tomography (CBCT) is an imaging system which has many advantages over computed tomography (CT). In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present study was to investigate the relationship between gray scale in CBCT) and Hounsfield Unit (HU) in CT scan. Materials and methods. In this descriptive study, the head of a sheep was scanned with 3 CBCT and one medical CT scanner. Gray scales and HUs were detected on images. Reconstructed data were analyzed to investigate relationship between CBCT gray scales and HUs. Results. A strong correlation between gray scales of CBCT and HUs of CT scan was determined. Conclusion. Considering the fact that gray scale in CBCT is the criteria in measurement of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  19. Texture-preserving Bayesian image reconstruction for low-dose CT

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Han, Hao; Hu, Yifan; Liu, Yan; Ma, Jianhua; Li, Lihong; Moore, William; Liang, Zhengrong

    2016-03-01

    Markov random field (MRF) model has been widely used in Bayesian image reconstruction to reconstruct piecewise smooth images in the presence of noise, such as in low-dose X-ray computed tomography (LdCT). While it can preserve edge sharpness via edge-preserving potential function, its regional smoothing may sacrifice tissue image textures, which have been recognized as useful imaging biomarkers, and thus it compromises clinical tasks such as differentiating malignant vs. benign lesions, e.g., lung nodule or colon polyp. This study aims to shift the edge preserving regional noise smoothing paradigm to texture-preserving framework for LdCT image reconstruction while retaining the advantage of MRF's neighborhood system on edge preservation. Specifically, we adapted the MRF model to incorporate the image textures of lung, bone, fat, muscle, etc. from previous full-dose CT scan as a priori knowledge for texture-preserving Bayesian reconstruction of current LdCT images. To show the feasibility of proposed reconstruction framework, experiments using clinical patient scans (with lung nodule or colon polyp) were conducted. The experimental outcomes showed noticeable gain by the a priori knowledge for LdCT image reconstruction with the well-known Haralick texture measures. Thus, it is conjectured that texture-preserving LdCT reconstruction has advantages over edge-preserving regional smoothing paradigm for texture-specific clinical applications.

  20. Postmortem CT angiography: capabilities and limitations in traumatic and natural causes of death.

    PubMed

    Ross, Steffen G; Bolliger, Stephan A; Ampanozi, Garyfalia; Oesterhelweg, Lars; Thali, Michael J; Flach, Patricia M

    2014-01-01

    Whole-body postmortem computed tomographic (CT) angiography is a promising new development in forensic radiology that has the potential to improve vascular and soft-tissue imaging beyond levels currently achievable with unenhanced postmortem CT. Postmortem access to the vascular system and injection of contrast medium are different from those steps in clinical (antemortem) radiology. Because there is no circulation in a corpse that could transport or dilute a contrast medium, the injection must be performed by using a roller pump to fill the vasculature (arterial and venous) with a mixture of a water-soluble iodized contrast medium and polyethylene glycol. In contrast to a classic autopsy, postmortem CT angiography is a minimally invasive procedure. It allows the diagnosis of vascular lesions without the disruption or destruction of anatomic structures, which could result in a loss of evidence in a criminal investigation. Furthermore, postmortem CT angiography facilitates the display of vascular pathologic conditions in areas that are not typically covered with autopsy alone, such as the craniocervical junction and the small pelvis. Therefore, postmortem CT angiography adds substantial value to the classic forensic autopsy; cross-sectional data can be reevaluated objectively at any time and are fully reproducible as counterexpertise, which is as useful in the fields of forensic medicine and pathology as in clinical research. Familiarity with the capabilities of postmortem CT angiography may help radiologists working with forensic cases improve their diagnostic performance.

  1. An update on the role of PET/CT and PET/MRI in ovarian cancer.

    PubMed

    Khiewvan, Benjapa; Torigian, Drew A; Emamzadehfard, Sahra; Paydary, Koosha; Salavati, Ali; Houshmand, Sina; Werner, Thomas J; Alavi, Abass

    2017-02-08

    This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as (18)F-fluorothymidine (FLT) or (11)C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer.

  2. Multirigid registration of MR and CT images of the cervical spine

    NASA Astrophysics Data System (ADS)

    Hu, Yangqiu; Haynor, David R.

    2004-05-01

    We present our work on fusion of MR and CT images of the cervical spine. To achieve the required registration accuracy of approximately 1mm, the spine is treated as a collection of rigid vertebrae, and a separate rigid body transformation applied to each (Hawkes). This in turn requires segmentation of the CT datasets into separate vertebral images, which is difficult because the narrow planes separating adjacent vertebrae are parallel to the axial plane of the CT scans. We solve this problem by evolving all the vertebral contours simultaneously using a level set method, and use contour competition to estimate the position of the vertebral edges when a clean separation between adjacent vertebrae is not seen. Contour competition is based in turn on the vertical scan principle: no part of a given vertebra is vertically below any part of an inferior vertebra. Once segmentation is complete, the individual rigid body transforms are then estimated using mutual information maximization, and the CT images of the vertebrae superimposed on the MR scans. The resultant fused images contain the bony detail of CT and the soft tissue discrimination of MR and appear to be diagnostically equivalent, or superior, to CT myelograms. A formal test of these conclusions is planned for the next phase of our work.

  3. MRI to CT prostate registration for improved targeting in cancer external beam radiotherapy.

    PubMed

    Commandeur, Frederic; Simon, Antoine; Mathieu, Romain; Nassef, Mohamed; Ospina, Juan David; Rolland, Yan; Haigron, Pascal; De Crevoisier, Renaud; Acosta, Oscar

    2016-06-16

    External radiotherapy is a major clinical treatment for localized prostate cancer. Currently, computed tomography (CT) is used to delineate the prostate and to plan the radiotherapy treatment. However, CT images suffer from a poor soft tissue contrast and do not allow an accurate organ delineation. On the contrary, Magnetic resonance imaging (MRI) provides rich details and high soft tissue contrast, allowing tumor detection. Thus, the intra-individual propagation of MRI delineations towards the planning CT may improve tumor targeting. In this paper we introduce a new method to propagate MRI prostate delineations to the planning CT. In a first step, a random forest (RF) classification is performed to coarsely detect the prostate in the CT images, yielding a prostate probability membership for each voxel and a prostate hard segmentation. Then the registration is performed using a new similarity metric which maximizes the probability and the collinearity between the normals of the MR existing contour and the contour resulting from the CT classification. A first study on synthetic data was performed to analyze the influence of the metric parameters with different levels of noise. Then, the method was also evaluated on real MR-CT data using manual alignments and intraprostatic fiducial markers and compared to a classically used mutual information (MI) approach. The proposed metric outperformed MI by 7% in terms of Dice score coefficient (DSC), by 3.14 mm the Hausdorff Distance (HD) and 2.13 mm the markers position errors (MPE). Finally, the impact of registration uncertainties on the treatment planning was evaluated, demonstrating the potential advantage of the proposed approach in a clinical setup to define a precise target.

  4. Photochemical tissue bonding

    DOEpatents

    Redmond, Robert W [Brookline, MA; Kochevar, Irene E [Charlestown, MA

    2012-01-10

    Photochemical tissue bonding methods include the application of a photosensitizer to a tissue and/or tissue graft, followed by irradiation with electromagnetic energy to produce a tissue seal. The methods are useful for tissue adhesion, such as in wound closure, tissue grafting, skin grafting, musculoskeletal tissue repair, ligament or tendon repair and corneal repair.

  5. CT of hepatic schistosomiasis mansoni

    SciTech Connect

    Fataar, S.; Bassiony, H.; Satyanath, S.; Rudwan, M.A.; Khaffaji, S.; El Magdy, W.; Al-Ansari, A.G.; Hanna, R.

    1985-07-01

    Schistosomal periportal fibrosis produced a typical pattern on computed tomography in five patients. Low-density periportal tissue, present throughout the liver, enhanced strongly after the administration of contrast medium. While rounded in cross section, the thickened periportal tissue produced linear and branching patterns when imaged in longitudinal section. In all cases, the sonographic features were typical of schistosomal periportal fibrosis. A lack of awareness of the distinctive features of periportal fibrosis may result in a mistaken diagnosis of hepatic metastases.

  6. Fast pseudo-CT synthesis from MRI T1-weighted images using a patch-based approach

    NASA Astrophysics Data System (ADS)

    Torrado-Carvajal, A.; Alcain, E.; Montemayor, A. S.; Herraiz, J. L.; Rozenholc, Y.; Hernandez-Tamames, J. A.; Adalsteinsson, E.; Wald, L. L.; Malpica, N.

    2015-12-01

    MRI-based bone segmentation is a challenging task because bone tissue and air both present low signal intensity on MR images, making it difficult to accurately delimit the bone boundaries. However, estimating bone from MRI images may allow decreasing patient ionization by removing the need of patient-specific CT acquisition in several applications. In this work, we propose a fast GPU-based pseudo-CT generation from a patient-specific MRI T1-weighted image using a group-wise patch-based approach and a limited MRI and CT atlas dictionary. For every voxel in the input MR image, we compute the similarity of the patch containing that voxel with the patches of all MR images in the database, which lie in a certain anatomical neighborhood. The pseudo-CT is obtained as a local weighted linear combination of the CT values of the corresponding patches. The algorithm was implemented in a GPU. The use of patch-based techniques allows a fast and accurate estimation of the pseudo-CT from MR T1-weighted images, with a similar accuracy as the patient-specific CT. The experimental normalized cross correlation reaches 0.9324±0.0048 for an atlas with 10 datasets. The high NCC values indicate how our method can accurately approximate the patient-specific CT. The GPU implementation led to a substantial decrease in computational time making the approach suitable for real applications.

  7. Micro-CT of Carotid Arteries: A Tool for Experimental Studies

    SciTech Connect

    Mohr, Andreas; Wenke, Ruediger; Roemer, Frank W.; Lynch, John A.; Gatzka, Christian; Priebe, Markus; Guermazi, Ali; Grigorian, Mikayel; Heller, Martin; Mueller-Huelsbeck, Stefan

    2004-11-15

    Micro-computed tomography (micro-CT) is a high-resolution, nondestructive tool for two- and three-dimensional imaging and quantification. The ability of this technique to assess atherosclerosis of the carotid artery was evaluated in three human cadaver samples based on the original axial acquisitions, multiplanar reconstructions and volume rendering techniques. Quantitative analysis included the calculation of: (1) the original lumen perimeter, original lumen area, plaque area, residual lumen area, calcified area and gross sectional area reduction of the vascular lumen from two-dimensional slices; (2) the total tissue volume, soft tissue volume and calcified tissue volume from the three-dimensional data set. This preliminary study demonstrates the potential of micro-CT as a supplementary method for the two- and three-dimensional ex vivo evaluation of carotid atherosclerosis.

  8. Design of anthropomorphic textured phantoms for CT performance evaluation

    NASA Astrophysics Data System (ADS)

    Solomon, Justin; Bochud, François; Samei, Ehsan

    2014-03-01

    Commercially available computed tomography (CT) technologies such as iterative reconstruction (IR) have the potential to enable reduced patient doses while maintaining diagnostic image quality. However, systematically determining safe dose reduction levels for IR algorithms is a challenging task due to their nonlinear nature. Most attempts to evaluate IR algorithms rely on measurements made in uniform phantoms. Such measurements may overstate the dose reduction potential of IR because they don't account for the complex relationship between anatomical variability and image quality. The purpose of this study was to design anatomically informed textured phantoms for CT performance evaluation. Two phantoms were designed to represent lung and soft-tissue textures. The lung phantom includes intricate vessel-like structures along with embedded nodules (spherical, lobulated, and spiculated). The soft tissue phantom was designed based on a three-dimensional clustered lumpy background with included low-contrast lesions (spherical and anthropomorphic). The phantoms were built using rapid prototyping (3D printing) technology and imaged on a modern multi-slice clinical CT scanner to assess the noise performance of a commercial IR algorithm in the context of uniform and textured backgrounds. Fifty repeated acquisitions were acquired for each background type and noise was assessed by measuring pixel standard deviation, across the ensemble of repeated acquisitions. For pixels in uniform areas, the IR algorithm reduced noise magnitude (STD) by 60% (compared to FBP). However, for edge pixels, the noise magnitude in the IR images ranged from 20% higher to 40% lower compared to FBP. In all FBP images and in IR images of the uniform phantom, noise appeared to be globally non-stationary (i.e., spatially dependent) but locally stationary (within a reasonably small region of interest). In the IR images of the textured phantoms, the noise was globally and locally non-stationary.

  9. Lung imaging in rodents using dual energy micro-CT

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C.; Piantadosi, C.

    2012-03-01

    Dual energy CT imaging is expected to play a major role in the diagnostic arena as it provides material decomposition on an elemental basis. The purpose of this work is to investigate the use of dual energy micro-CT for the estimation of vascular, tissue, and air fractions in rodent lungs using a post-reconstruction three-material decomposition method. We have tested our method using both simulations and experimental work. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact lungs were carefully removed from the thorax, were injected with an iodine-based contrast agent and inflated with air at different volume levels. Finally, we performed in vivo imaging studies in (n=5) C57BL/6 mice using fast prospective respiratory gating in endinspiration and end-expiration for three different levels of positive end-expiratory pressure (PEEP). Prior to imaging, mice were injected with a liposomal blood pool contrast agent. The mean accuracy values were for Air (95.5%), Blood (96%), and Tissue (92.4%). The absolute accuracy in determining all fraction materials was 94.6%. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end-expiration, but no significant changes in end-inspiration. Our method has applicability in preclinical pulmonary studies where various physiological changes can occur as a result of genetic changes, lung disease, or drug effects.

  10. Functional imaging of interstitial brachytherapy in pancreatic carcinoma xenografts using spectral CT: how does iodine concentration correlate with standardized uptake value of 18FDG-PET-CT?

    PubMed Central

    Hu, Shudong; Shi, Xiaofeng; Chen, Yerong; Huang, Wei; Song, Qi; Lin, Xiaozhu; Liu, Yu; Chen, Kemin

    2016-01-01

    Objective: This study aimed to investigate the correlation between iodine concentration (IC) for the quantitative analysis of spectral CT and maximum standardized uptake value (SUVmax) of 18 fludeoxyglucose positron emission tomography–CT (18FDG PET–CT) as an indicator of therapeutic response to interstitial brachytherapy in transplanted human pancreatic carcinomas in BALB/c-nu mice. Methods: Xenograft models were created by subcutaneous injection of SW1990 human pancreatic cancer cell suspensions into immunodeficient BALB/c-nu mice. 30 mice bearing SW1990 human pancreatic cancer cell xenografts were randomly separated into two groups: experimental (n = 15; 1.0 mCi) and control (n = 15, 0 mCi). After 2 weeks of treatment, spectral CT and 18FDG micro-PET–CT scan were performed. IC values and SUVmax in the lesions were measured. IC normalized to the muscle tissue is indicated as nIC. The relationships between the nIC and SUVmax of the transplantation tumours were analysed. Results: 2 weeks after treatment, the nIC in three-phase scans and SUVmax of the experimental group were significantly lower than those of the control group. The nIC values of the three-phase scans have certain positive correlation with the SUVmax values (r = 0.69, p < 0.05; r = 0.73 and p < 0.05; r = 0.80, p < 0.05 in the 10-, 25- and 60-s phase, respectively). Conclusion: Spectral CT could serve as a valuable imaging modality, as our results suggest that nIC correlates with SUVmax of 18FDG PET–CT for evaluating the therapeutic effect of 125I interstitial brachytherapy in a pancreatic carcinoma xenograft. Advances in knowledge: Spectral CT offers opportunities to assess the therapeutic response of pancreatic cancer. This study supports the conclusion that nIC values in spectral CT could also serve as a valuable functional imaging parameter for early monitoring and evaluation of the therapeutic response of 125I interstitial brachytherapy mouse models

  11. Recent technologic advances in multi-detector row cardiac CT.

    PubMed

    Halliburton, Sandra Simon

    2009-11-01

    Recent technical advances in multi-detector row CT have resulted in lower radiation dose, improved temporal and spatial resolution, decreased scan time, and improved tissue differentiation. Lower radiation doses have resulted from the use of pre-patient z collimators, the availability of thin-slice axial data acquisition, the increased efficiency of ECG-based tube current modulation, and the implementation of iterative reconstruction algorithms. Faster gantry rotation and the simultaneous use of two x-ray sources have led to improvements in temporal resolution, and gains in spatial resolution have been achieved through application of the flying x-ray focal-spot technique in the z-direction. Shorter scan times have resulted from the design of detector arrays with increasing numbers of detector rows and through the simultaneous use of two x-ray sources to allow higher helical pitch. Some improvement in tissue differentiation has been achieved with dual energy CT. This article discusses these recent technical advances in detail.

  12. Tissue Photolithography

    NASA Technical Reports Server (NTRS)

    Wade, Lawrence A.; Kartalov, Emil; Shibata, Darryl; Taylor, Clive

    2011-01-01

    Tissue lithography will enable physicians and researchers to obtain macromolecules with high purity (greater than 90 percent) from desired cells in conventionally processed, clinical tissues by simply annotating the desired cells on a computer screen. After identifying the desired cells, a suitable lithography mask will be generated to protect the contents of the desired cells while allowing destruction of all undesired cells by irradiation with ultraviolet light. The DNA from the protected cells can be used in a number of downstream applications including DNA sequencing. The purity (i.e., macromolecules isolated form specific cell types) of such specimens will greatly enhance the value and information of downstream applications. In this method, the specific cells are isolated on a microscope slide using photolithography, which will be faster, more specific, and less expensive than current methods. It relies on the fact that many biological molecules such as DNA are photosensitive and can be destroyed by ultraviolet irradiation. Therefore, it is possible to protect the contents of desired cells, yet destroy undesired cells. This approach leverages the technologies of the microelectronics industry, which can make features smaller than 1 micrometer with photolithography. A variety of ways has been created to achieve identification of the desired cell, and also to designate the other cells for destruction. This can be accomplished through chrome masks, direct laser writing, and also active masking using dynamic arrays. Image recognition is envisioned as one method for identifying cell nuclei and cell membranes. The pathologist can identify the cells of interest using a microscopic computerized image of the slide, and appropriate custom software. In one of the approaches described in this work, the software converts the selection into a digital mask that can be fed into a direct laser writer, e.g. the Heidelberg DWL66. Such a machine uses a metalized glass plate (with

  13. 64CuCl2 PET/CT imaging of mouse muscular injury induced by electroporation

    PubMed Central

    Xie, Fang; Cai, Huawei; Peng, Fangyu

    2017-01-01

    Skeletal muscle injury is common in body injuries suffered in sports and car accidents. Development of new tracers is significant for assessing muscular injury with positron emission tomography/computed tomography (PET/CT) and monitoring repair of muscle injury in response to treatment. Copper is required for wound healing and increased copper ions were detected in the soft tissue of wound in rodents and human. Based on the recent finding of increased 64Cu uptake in the traumatic brain injury, this study aimed to explore use of 64CuCl2 as a radiotracer for molecular imaging of muscular injury using PET/CT. Focally increased 64Cu uptake by the injured muscular tissue (5.4 ± 1.2% ID/g) was detected in the C57BL/6 mice with electroporation-induced skeletal muscle injury by PET/CT after intravenous injection of 64CuCl2 as a tracer, compared to low 64Cu uptake associated with muscular inflammation induced by intramuscular injection of lipopolysaccharides (0.82 ± 0.26% ID/g, P < 0.01) or physiological 64Cu uptake of the non-injured muscular tissues (0.78 ± 0.20% ID/g, P < 0.01). The findings support further investigation of 64CuCl2 as a new radiotracer for molecular imaging of skeletal muscle injury using PET/CT. PMID:28123866

  14. Early Cerebral Circulation Disturbance in Patients Suffering from Severe Traumatic Brain Injury (TBI): A Xenon CT and Perfusion CT Study.

    PubMed

    Honda, Mitsuru; Ichibayashi, Ryo; Yokomuro, Hiroki; Yoshihara, Katsunori; Masuda, Hiroyuki; Haga, Daisuke; Seiki, Yoshikatsu; Kudoh, Chiaki; Kishi, Taichi

    2016-08-15

    Traumatic brain injury (TBI) is widely known to cause dynamic changes in cerebral blood flow (CBF). Ischemia is a common and deleterious secondary injury following TBI. Detecting early ischemia in TBI patients is important to prevent further advancement and deterioration of the brain tissue. The purpose of this study was to clarify the cerebral circulatory disturbance during the early phase and whether it can be used to predict patient outcome. A total of 90 patients with TBI underwent a xenon-computed tomography (Xe-CT) and subsequently perfusion CT to evaluate the cerebral circulation on days 1-3. We measured CBF using Xe-CT and mean transit time (MTT: the width between two inflection points [maximum upward slope and maximum downward slope from inflow to outflow of the contrast agent]) using perfusion CT and calculated the cerebral blood volume (CBV) using the AZ-7000W98 computer system. The relationships of the hemodynamic parameters CBF, MTT, and CBV to the Glasgow Coma Scale (GCS) score and the Glasgow Outcome Scale (GOS) score were examined. There were no significant differences in CBF, MTT, and CBV among GCS3-4, GCS5-6, and GCS7-8 groups. The patients with a favorable outcome (GR and MD) had significantly higher CBF and lower MTT than those with an unfavorable one (SD, VS, or D). The discriminant analysis of these parameters could predict patient outcome with a probability of 70.6%. During the early phase, CBF reduction and MTT prolongation might influence the clinical outcome of TBI. These parameters are helpful for evaluating the severity of cerebral circulatory disturbance and predicting the outcome of TBI patients.

  15. Early Cerebral Circulation Disturbance in Patients Suffering from Severe Traumatic Brain Injury (TBI): A Xenon CT and Perfusion CT Study

    PubMed Central

    HONDA, Mitsuru; ICHIBAYASHI, Ryo; YOKOMURO, Hiroki; YOSHIHARA, Katsunori; MASUDA, Hiroyuki; HAGA, Daisuke; SEIKI, Yoshikatsu; KUDOH, Chiaki; KISHI, Taichi

    2016-01-01

    Traumatic brain injury (TBI) is widely known to cause dynamic changes in cerebral blood flow (CBF). Ischemia is a common and deleterious secondary injury following TBI. Detecting early ischemia in TBI patients is important to prevent further advancement and deterioration of the brain tissue. The purpose of this study was to clarify the cerebral circulatory disturbance during the early phase and whether it can be used to predict patient outcome. A total of 90 patients with TBI underwent a xenon-computed tomography (Xe-CT) and subsequently perfusion CT to evaluate the cerebral circulation on days 1–3. We measured CBF using Xe-CT and mean transit time (MTT: the width between two inflection points [maximum upward slope and maximum downward slope from inflow to outflow of the contrast agent]) using perfusion CT and calculated the cerebral blood volume (CBV) using the AZ-7000W98 computer system. The relationships of the hemodynamic parameters CBF, MTT, and CBV to the Glasgow Coma Scale (GCS) score and the Glasgow Outcome Scale (GOS) score were examined. There were no significant differences in CBF, MTT, and CBV among GCS3–4, GCS5–6, and GCS7–8 groups. The patients with a favorable outcome (GR and MD) had significantly higher CBF and lower MTT than those with an unfavorable one (SD, VS, or D). The discriminant analysis of these parameters could predict patient outcome with a probability of 70.6%. During the early phase, CBF reduction and MTT prolongation might influence the clinical outcome of TBI. These parameters are helpful for evaluating the severity of cerebral circulatory disturbance and predicting the outcome of TBI patients. PMID:27356957

  16. CT enterography with polyethylene glycol solution vs CT enteroclysis in small bowel disease

    PubMed Central

    Minordi, L M; Vecchioli, A; Mirk, P; Bonomo, L

    2011-01-01

    Objective The aim of the study is to compare CT enterography with polyethylene glycol solution (PEG-CT) with CT enteroclysis (CT-E) in patients with suspected small bowel disease. Methods 145 patients underwent abdominal contrast-enhanced 16-row multidetector CT after administration of 2000 ml of PEG by mouth (n = 75) or after administration of 2000 ml of methylcellulose by nasojejunal tube (n = 70). Small bowel distension, luminal and extraluminal findings were evaluated and compared with small bowel follow-through examination in 60 patients, double contrast enema in 50, surgery in 25 and endoscopy in 35. Statistical evaluation was carried out by χ2 testing. For both techniques we have also calculated the effective dose and the equivalent dose in a standard patient. Results Crohn's disease was diagnosed in 64 patients, neoplasms in 16, adhesions in 6. Distension of the jejunum was better with CT-E than PEG-CT (p<0.05: statistically significant difference). No significant difference was present for others sites (p>0.05). Evaluation of pathological ileal loops was good with both techniques. The values of sensitivity, specificity and diagnostic accuracy were respectively 94%, 100% and 96% with CT-E, and 93%, 94% and 93% with PEG-CT. The effective dose for PEG-CT was less than the dose for the CT-E (34.7 mSv vs 39.91 mSv). Conclusion PEG-CT shows findings of Crohn's disease as well as CT-E does, although CT-E gives better bowel distension, especially in the jejunum, and has higher specificity than PEG-CT. PMID:20959377

  17. Automatic detection and segmentation of liver metastatic lesions on serial CT examinations

    NASA Astrophysics Data System (ADS)

    Ben Cohen, Avi; Diamant, Idit; Klang, Eyal; Amitai, Michal; Greenspan, Hayit

    2014-03-01

    In this paper we present a fully automated method for detection and segmentation of liver metastases on serial CT examinations (portal phase) given a 2D baseline segmentation mask. Our database contains 27 CT scans, baselines and follow-ups, of 12 patients and includes 22 test cases. Our method is based on the information given in the baseline CT scan which contains the lesion's segmentation mask marked manually by a radiologist. We use the 2D baseline segmentation mask to identify the lesion location in the follow-up CT scan using non-rigid image registration. The baseline CT scan is also used to locate regions of tissues surrounding the lesion and to map them onto the follow-up CT scan, in order to reduce the search area on the follow-up CT scan. Adaptive region-growing and mean-shift segmentation are used to obtain the final lesion segmentation. The segmentation results are compared to those obtained by a human radiologist. Compared to the reference standard our method made a correct RECIST 1.1 assessment for 21 out of 22 test cases. The average Dice index was 0.83 +/- 0.07, average Hausdorff distance was 7.85+/- 4.84 mm, average sensitivity was 0.87 +/- 0.11 and positive predictive value was 0.81 +/- 0.10. The segmentation performance and the RECIST assessment results look promising. We are pursuing the methodology further with expansion to 3D segmentation while increasing the dataset we are collecting from the CT abdomen unit at Sheba medical center.

  18. SU-E-J-135: Feasibility of Using Quantitative Cone Beam CT for Proton Adaptive Planning

    SciTech Connect

    Jingqian, W; Wang, Q; Zhang, X; Wen, Z; Zhu, X; Frank, S; Li, H; Tsui, T; Zhu, L; Wei, J

    2015-06-15

    Purpose: To investigate the feasibility of using scatter corrected cone beam CT (CBCT) for proton adaptive planning. Methods: Phantom study was used to evaluate the CT number difference between the planning CT (pCT), quantitative CBCT (qCBCT) with scatter correction and calibrated Hounsfield units using adaptive scatter kernel superposition (ASKS) technique, and raw CBCT (rCBCT). After confirming the CT number accuracy, prostate patients, each with a pCT and several sets of weekly CBCT, were investigated for this study. Spot scanning proton treatment plans were independently generated on pCT, qCBCT and rCBCT. The treatment plans were then recalculated on all images. Dose-volume-histogram (DVH) parameters and gamma analysis were used to compare between dose distributions. Results: Phantom study suggested that Hounsfield unit accuracy for different materials are within 20 HU for qCBCT and over 250 HU for rCBCT. For prostate patients, proton dose could be calculated accurately on qCBCT but not on rCBCT. When the original plan was recalculated on qCBCT, tumor coverage was maintained when anatomy was consistent with pCT. However, large dose variance was observed when patient anatomy change. Adaptive plan using qCBCT was able to recover tumor coverage and reduce dose to normal tissue. Conclusion: It is feasible to use qu antitative CBCT (qCBCT) with scatter correction and calibrated Hounsfield units for proton dose calculation and adaptive planning in proton therapy. Partly supported by Varian Medical Systems.

  19. CT image artifacts from brachytherapy seed implants: A postprocessing 3D adaptive median filter

    SciTech Connect

    Basran, Parminder S.; Robertson, Andrew; Wells, Derek

    2011-02-15

    Purpose: To design a postprocessing 3D adaptive median filter that minimizes streak artifacts and improves soft-tissue contrast in postoperative CT images of brachytherapy seed implantations. Methods: The filter works by identifying voxels that are likely streaks and estimating more reflective voxel intensity by using voxel intensities in adjacent CT slices and applying a median filter over voxels not identified as seeds. Median values are computed over a 5x5x5 mm region of interest (ROI) within the CT volume. An acrylic phantom simulating a clinical seed implant arrangement and containing nonradioactive seeds was created. Low contrast subvolumes of tissuelike material were also embedded in the phantom. Pre- and postprocessed image quality metrics were compared using the standard deviation of ROIs between the seeds, the CT numbers of low contrast ROIs embedded within the phantom, the signal to noise ratio (SNR), and the contrast to noise ratio (CNR) of the low contrast ROIs. The method was demonstrated with a clinical postimplant CT dataset. Results: After the filter was applied, the standard deviation of CT values in streak artifact regions was significantly reduced from 76.5 to 7.2 HU. Within the observable low contrast plugs, the mean of all ROI standard deviations was significantly reduced from 60.5 to 3.9 HU, SNR significantly increased from 2.3 to 22.4, and CNR significantly increased from 0.2 to 4.1 (all P<0.01). The mean CT in the low contrast plugs remained within 5 HU of the original values. Conclusion: An efficient postprocessing filter that does not require access to projection data, which can be applied irrespective of CT scan parameters has been developed, provided the slice thickness and spacing is 3 mm or less.

  20. Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT

    NASA Astrophysics Data System (ADS)

    Jansen, Jan T. M.; Shrimpton, Paul C.

    2016-07-01

    The ImPACT (imaging performance assessment of CT scanners) CT patient dosimetry calculator is still used world-wide to estimate organ and effective doses (E) for computed tomography (CT) examinations, although the tool is based on Monte Carlo calculations reflecting practice in the early 1990’s. Subsequent developments in CT scanners, definitions of E, anthropomorphic phantoms, computers and radiation transport codes, have all fuelled an urgent need for updated organ dose conversion factors for contemporary CT. A new system for such simulations has been developed and satisfactorily tested. Benchmark comparisons of normalised organ doses presently derived for three old scanners (General Electric 9800, Philips Tomoscan LX and Siemens Somatom DRH) are within 5% of published values. Moreover, calculated normalised values of CT Dose Index for these scanners are in reasonable agreement (within measurement and computational uncertainties of  ±6% and  ±1%, respectively) with reported standard measurements. Organ dose coefficients calculated for a contemporary CT scanner (Siemens Somatom Sensation 16) demonstrate potential deviations by up to around 30% from the surrogate values presently assumed (through a scanner matching process) when using the ImPACT CT Dosimetry tool for newer scanners. Also, illustrative estimates of E for some typical examinations and a range of anthropomorphic phantoms demonstrate the significant differences (by some 10’s of percent) that can arise when changing from the previously adopted stylised mathematical phantom to the voxel phantoms presently recommended by the International Commission on Radiological Protection (ICRP), and when following the 2007 ICRP recommendations (updated from 1990) concerning tissue weighting factors. Further simulations with the validated dosimetry system will provide updated series of dose coefficients for a wide range of contemporary scanners.

  1. Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT.

    PubMed

    Jansen, Jan T M; Shrimpton, Paul C

    2016-07-21

    The ImPACT (imaging performance assessment of CT scanners) CT patient dosimetry calculator is still used world-wide to estimate organ and effective doses (E) for computed tomography (CT) examinations, although the tool is based on Monte Carlo calculations reflecting practice in the early 1990's. Subsequent developments in CT scanners, definitions of E, anthropomorphic phantoms, computers and radiation transport codes, have all fuelled an urgent need for updated organ dose conversion factors for contemporary CT. A new system for such simulations has been developed and satisfactorily tested. Benchmark comparisons of normalised organ doses presently derived for three old scanners (General Electric 9800, Philips Tomoscan LX and Siemens Somatom DRH) are within 5% of published values. Moreover, calculated normalised values of CT Dose Index for these scanners are in reasonable agreement (within measurement and computational uncertainties of  ±6% and  ±1%, respectively) with reported standard measurements. Organ dose coefficients calculated for a contemporary CT scanner (Siemens Somatom Sensation 16) demonstrate potential deviations by up to around 30% from the surrogate values presently assumed (through a scanner matching process) when using the ImPACT CT Dosimetry tool for newer scanners. Also, illustrative estimates of E for some typical examinations and a range of anthropomorphic phantoms demonstrate the significant differences (by some 10's of percent) that can arise when changing from the previously adopted stylised mathematical phantom to the voxel phantoms presently recommended by the International Commission on Radiological Protection (ICRP), and when following the 2007 ICRP recommendations (updated from 1990) concerning tissue weighting factors. Further simulations with the validated dosimetry system will provide updated series of dose coefficients for a wide range of contemporary scanners.

  2. Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware.

    PubMed

    Vande Berg, Bruno; Malghem, Jacques; Maldague, Baudouin; Lecouvet, Frederic

    2006-12-01

    Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.

  3. CT detection of intraabdominal disease in patients with lower extremity signs and symptoms.

    PubMed

    Meshkov, S L; Seltzer, S E; Finberg, H J

    1982-06-01

    The initial clinical presentation of intraabdominal disease can be in an extraabdominal location. This phenomenon most commonly occurs in the setting of bowel perforation secondary to diverticulitis, appendicitis, or carcinoma, with resultant spread of infection caudal to the abdomen. Hematomas and pancreatic fluid collections may also dissect out of the abdomen. The spread of these disease processes is likely to occur in a predictable fashion along anatomic tissue planes. Computed tomography (CT) is well suited to demonstrate the extraabdominal site of disease, the pathway of spread from the abdomen, and the occult intraabdominal process. We describe four such cases in which CT was useful and discuss the anatomic pathways involved.

  4. In vivo tissue engineering of musculoskeletal tissues.

    PubMed

    McCullen, Seth D; Chow, Andre G Y; Stevens, Molly M

    2011-10-01

    Tissue engineering of musculoskeletal tissues often involves the in vitro manipulation and culture of progenitor cells, growth factors and biomaterial scaffolds. Though in vitro tissue engineering has greatly increased our understanding of cellular behavior and cell-material interactions, this methodology is often unable to recreate tissue with the hierarchical organization and vascularization found within native tissues. Accordingly, investigators have focused on alternative in vivo tissue engineering strategies, whereby the traditional triad (cells, growth factors, scaffolds) or a combination thereof are directly implanted at the damaged tissue site or within ectopic sites capable of supporting neo-tissue formation. In vivo tissue engineering may offer a preferential route for regeneration of musculoskeletal and other tissues with distinct advantages over in vitro methods based on the specific location of endogenous cultivation, recruitment of autologous cells, and patient-specific regenerated tissues.

  5. Evaluation of the potential utility of flat panel CT for quantifying relative contrast enhancement

    SciTech Connect

    Jones, A. Kyle; Mahvash, Armeen

    2012-07-15

    Purpose: Certain directed oncologic therapies seek to take advantage of the fact that tumors are typically more susceptible to directed therapeutic agents than normal tissue owing to their extensive networks of poorly formed, leaky vasculature. If differences between the vascularity of normal and tumor tissues could be quantified, patients could be selected for or excluded from directed treatments on the basis of this difference. However, angiographic imaging techniques such as digital subtraction angiography (DSA) yield two-dimensional data that may be inadequate for this task. As a first step, the authors evaluated the feasibility of using a commercial implementation of flat panel computed tomography (FPCT) to quantify differences in enhancement of a simulated tumor compared with normal tissue based on differences in CT number measured in precontrast and postcontrast scans. Methods: To evaluate the FPCT scanner studied, the authors scanned several phantoms containing simulated normal and tumor tissues. In the first experiment, the authors used an anthropomorphic phantom containing inclusions representing normal, tumor, and bone tissue to evaluate the constancy of CT numbers in scans repeated at clinically relevant intervals of 1 and 3 min. The authors then scanned gelatin phantoms containing dilutions of iodinated contrast to evaluate the accuracy of relative contrast enhancement measurements for a clinical FPCT system. Data were analyzed using widely available software. Results: CT numbers measured in identical locations were constant over both scan intervals evaluated. Measured relative contrast enhancement values were accurate compared with known relative contrast enhancement values. Care must be taken to avoid artifacts in reconstructed images when placing regions of interest. Conclusions: Despite its limitations, FPCT in the interventional laboratory can be used to quantify relative contrast enhancement in phantoms. This is accomplished by measuring CT

  6. CT demonstration of bilateral adrenal hemorrhage

    SciTech Connect

    Ling, D.; Korobkin, M.; Silverman, P.M.; Dunnick, N.R.

    1983-08-01

    Bilateral adrenal hemorrhage with subsequent adrenal insufficiency is a recognized complication of anticoagulant therapy. Because the clinical manifestations are often nonspecific, the antemortem diagnosis of adrenal hemorrhage has been a difficult clinical problem. Computed tomography (CT) provides detailed images of the adrenal glands that are not possible with conventional imaging methods. The CT findings of bilateral adrenal hemorrhage in an anticoagulated patient are reported.

  7. Reconstructing misaligned x-ray CT data

    SciTech Connect

    Divin, C. J.

    2016-10-24

    Misalignment errors for x-ray computed tomography (CT) systems can manifest as artifacts and a loss of spatial and contrast resolution. To mitigate artifacts, significant effort is taken to determine the system geometry and minimizing any residual error in the system alignment. This project improved our ability to post-correct data which was acquired on a misaligned CT system.

  8. CT of schistosomal calcification of the intestine

    SciTech Connect

    Fataar, S.; Bassiony, H.; Satyanath, S.; Rudwan, M.; Hebbar, G.; Khalifa, A.; Cherian, M.J.

    1985-01-01

    The spectrum of schistosomal colonic calcification on abdominal radiographs has been described. The appearance on computed tomography (CT) is equally distinctive and occurs with varying degrees of genitourinary calcification. The authors have experience in three cases with the appearance on CT of intestinal calcification due to schistosomiasis.

  9. State-of-the-art in CT hardware and scan modes for cardiovascular CT

    PubMed Central

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J.; Gentry, Ralph; George, Richard T.; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm. Guy

    2013-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and the coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography (SCCT) Basic and Emerging Sciences and Technology (BEST) Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging. PMID:22551595

  10. State-of-the-art in CT hardware and scan modes for cardiovascular CT.

    PubMed

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J; Gentry, Ralph; George, Richard T; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm Guy

    2012-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography Basic and Emerging Sciences and Technology Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging.

  11. Female pelvic synthetic CT generation based on joint intensity and shape analysis

    NASA Astrophysics Data System (ADS)

    Liu, Lianli; Jolly, Shruti; Cao, Yue; Vineberg, Karen; Fessler, Jeffrey A.; Balter, James M.

    2017-04-01

    Using MRI for radiotherapy treatment planning and image guidance is appealing as it provides superior soft tissue information over CT scans and avoids possible systematic errors introduced by aligning MR to CT images. This study presents a method that generates Synthetic CT (MRCT) volumes by performing probabilistic tissue classification of voxels from MRI data using a single imaging sequence (T1 Dixon). The intensity overlap between different tissues on MR images, a major challenge for voxel-based MRCT generation methods, is addressed by adding bone shape information to an intensity-based classification scheme. A simple pelvic bone shape model, built from principal component analysis of pelvis shape from 30 CT image volumes, is fitted to the MR volumes. The shape model generates a rough bone mask that excludes air and covers bone along with some surrounding soft tissues. Air regions are identified and masked out from the tissue classification process by intensity thresholding outside the bone mask. A regularization term is added to the fuzzy c-means classification scheme that constrains voxels outside the bone mask from being assigned memberships in the bone class. MRCT image volumes are generated by multiplying the probability of each voxel being represented in each class with assigned attenuation values of the corresponding class and summing the result across all classes. The MRCT images presented intensity distributions similar to CT images with a mean absolute error of 13.7 HU for muscle, 15.9 HU for fat, 49.1 HU for intra-pelvic soft tissues, 129.1 HU for marrow and 274.4 HU for bony tissues across 9 patients. Volumetric modulated arc therapy (VMAT) plans were optimized using MRCT-derived electron densities, and doses were recalculated using corresponding CT-derived density grids. Dose differences to planning target volumes were small with mean/standard deviation of 0.21/0.42 Gy for D0.5cc and 0.29/0.33 Gy for D99%. The results demonstrate the accuracy of the

  12. Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT)

    SciTech Connect

    Pai, Vinay M.; Kozlowski, Megan; Donahue, Danielle; Miller, Elishiah; Xiao, Xianghui; Chen, Marcus Y.; Yu, Zu-Xi; Connelly, Patricia; Jeffries, Kenneth; Wen, Han

    2012-05-10

    The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO{sub 4}) solution. As a tissue-staining contrast agent, OsO{sub 4} is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO{sub 4} preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE{sup -/-}) mice at 10 {mu}m resolution. The results show that walls of coronary arteries as small as 45 {mu}m in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO{sub 4} and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.

  13. Opportunities for new CT contrast agents to maximize the diagnostic potential of emerging spectral CT technologies.

    PubMed

    Yeh, Benjamin M; FitzGerald, Paul F; Edic, Peter M; Lambert, Jack W; Colborn, Robert E; Marino, Michael E; Evans, Paul M; Roberts, Jeannette C; Wang, Zhen J; Wong, Margaret J; Bonitatibus, Peter J

    2016-09-09

    The introduction of spectral CT imaging in the form of fast clinical dual-energy CT enabled contrast material to be differentiated from other radiodense materials, improved lesion detection in contrast-enhanced scans, and changed the way that existing iodine and barium contrast materials are used in clinical practice. More profoundly, spectral CT can differentiate between individual contrast materials that have different reporter elements such that high-resolution CT imaging of multiple contrast agents can be obtained in a single pass of the CT scanner. These spectral CT capabilities would be even more impactful with the development of contrast materials designed to complement the existing clinical iodine- and barium-based agents. New biocompatible high-atomic number contrast materials with different biodistribution and X-ray attenuation properties than existing agents will expand the diagnostic power of spectral CT imaging without penalties in radiation dose or scan time.

  14. Dual source CT (DSCT) imaging of obese patients: evaluation of CT number accuracy, uniformity, and noise

    NASA Astrophysics Data System (ADS)

    Walz-Flannigan, A.; Schmidt, B.,; Apel, A.; Eusemann, C.; Yu, L.; McCollough, C. H.

    2009-02-01

    Obese patients present challenges in obtaining sufficient x-ray exposure over reasonable time periods for acceptable CT image quality. To overcome this limitation, the exposure can be divided between two x-ray sources using a dualsource (DS) CT system. However, cross-scatter issues in DS CT may also compromise image quality. We evaluated a DS CT system optimized for imaging obese patients, comparing the CT number accuracy and uniformity to the same images obtained with a single-source (SS) acquisition. The imaging modes were compared using both solid cylindrical PMMA phantoms and a semi-anthropomorphic thorax phantom fitted with extension rings to simulate different size patients. Clinical protocols were used and CTDIvol and kVp were held constant between SS and DS modes. Results demonstrated good agreement in CT number between SS and DS modes in CT number, with the DS mode showing better axial uniformity for the largest phantoms.

  15. 18F-FDG PET/CT demonstrating primary bone lymphoma of the extremities mimicking an inflammatory peripheral arthropathy.

    PubMed

    Tachibana, Ayano; Robinson, Richard J; Patel, Chirag N

    2015-02-01

    A 66-year-old woman presents with progressive bilateral swelling of her fingers, elbows, and toes. Initially thought to represent an inflammatory peripheral arthropathy, the patient underwent rheumatology review, but subsequent tissue biopsy confirmed diffuse large B-cell lymphoma. Results of bone marrow biopsy and staging CT were negative. F-FDG PET/CT demonstrates FDG-avid bony and adjacent soft tissue disease limited to the extremities with an excellent metabolic response to primary chemotherapy. This is a rare case of primary bone lymphoma limited to the extremities mimicking an inflammatory peripheral arthropathy.

  16. Beam hardening correction for computed tomography images using a postreconstruction method and equivalent tissue concept.

    PubMed

    Chen, C Y; Chuang, K S; Wu, J; Lin, H R; Li, M J

    2001-06-01

    A postreconstruction method for correcting the beam-hardening artifacts in computed tomography (CT) images is proposed. This method does not require x-ray spectrum measurement. The authors assumed that a pixel in a CT image can be decomposed into equivalent tissue percentages, depending on its CT number. A scout view of the step wedges made of these equivalent tissues was performed to obtain a beam-hardening correction curve for each tissue. Projecting through the CT image from various angles generated simulated projection data and the total thickness of each tissue along the ray. The correction term was estimated using the tissue thickness traveled by the ray, and this term was then added to its corresponding projection data. A second reconstruction using the corrected projection data yielded a beam-hardening corrected image. The preliminary results show that this method reduces beam hardening artifacts by 14% for aluminum and increased the object contrast by 18% near the aluminum-water boundary. The variation in CT numbers at different locations were reduced, and the aluminum CT number also was restored.

  17. Computed tomography diffraction-enhanced imaging for in situ visualization of tissue scaffolds implanted in cartilage.

    PubMed

    Izadifar, Zohreh; Chapman, Leroy Dean; Chen, Xiongbiao

    2014-02-01

    Long-term in vivo studies on animal models and advances from animal to human studies should rely on noninvasive monitoring methods. Synchrotron radiation (SR)-diffraction enhanced imaging (DEI) has shown great promise as a noninvasive method for visualizing native and/or engineered tissues and bio-microstructures with appreciable details in situ. The objective of this study was to investigate SR-DEI for in situ visualization and characterization of tissue-engineered scaffolds implanted in cartilage. A piglet stifle joint implanted with an engineered scaffold made from poly-ɛ-caprolactone was imaged using SR computed tomography (CT)-DEI at an X-ray energy of 40 keV. For comparison, in situ visualization was also conducted with commonly used SR CT-phase contrast imaging and clinical magnetic resonance imaging techniques. The reconstructed CT-DE images show the implanted scaffold with the structural properties much clearer than those in the CT-PC and MR images. Furthermore, CT-DEI was able to visualize microstructures within the cartilage as well as different soft tissues surrounding the joint. These microstructural details were not recognizable using other imaging techniques. Taken together, the results of this study suggest that CT-DEI can be used for noninvasive visualization and characterization of scaffolds in cartilage, representing an advance in tissue engineering to track the success of tissue scaffolds for cartilage repair.

  18. Differentiating tissue by fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Woessner, Stefan; Huen, Julien; Malthan, Dirk

    2004-03-01

    A common problem in several surgical applications is the lack of navigational information. Most often, the only source of information about the location of crucial structures, in relation to the surgical instrument, is the visible and tactile sensory input of the surgeon. In some cases, this leads to time-consuming procedures and a high risk for the patient. Therefore, we developed a spectroscopic sensor system for automatic differentiation between several tissue types. For example in milling processes, a sensor that is able to detect bone in contrast to nerve or vein tissue can be used to control the milling process. We showed exemplarily for the cochlea implant, a typical ENT-surgery, that with the help of our sensor system, the milling of bone can be accelerated without increasing the risk for the patient. It is also possible to use this type of sensor system in the area of medical robotics in soft-tissue applications. With real-time information, a continuous registration can take place, in contrast to a registration that is done using static preoperatively acquired images. We showed that our sensor system can be used to dynamically update the location of the patient in relation to CT or MR-images. In conclusion, we have been able to show that well-known spectroscopy sensors can be used to open new possibilities in medical treatment with and without the use of robotics.

  19. In-patient to isocenter KERMA ratios in CT

    SciTech Connect

    Huda, Walter; Ogden, Kent M.; Lavallee, Robert L.; Roskopf, Marsha L.; Scalzetti, Ernest M.

    2011-10-15

    Purpose: To estimate in-patient KERMA for specific organs in computed tomography (CT) scanning using ratios to isocenter free-in-air KERMA obtained using a Rando phantom.Method: A CT scan of an anthropomorphic phantom results in an air KERMA K at a selected phantom location and air kerma K{sub CT} at the CT scanner isocenter when the scan is repeated in the absence of the phantom. The authors define the KERMA ratio (R{sub K}) as K/ K{sub CT}, which were experimentally determined in a Male Rando Phantom using lithium fluoride chips (TLD-100). R{sub K} values were obtained for a total of 400 individual point locations, as well as for 25 individual organs of interest in CT dosimetry. CT examinations of Rando were performed on a GE LightSpeed Ultra scanner operated at 80 kV, 120 kV, and 140 kV, as well as a Siemens Sensation 16 operated at 120 kV. Results: At 120 kV, median R{sub K} values for the GE and Siemens scanners were 0.60 and 0.64, respectively. The 10th percentile R{sub K} values ranged from 0.34 at 80 kV to 0.54 at 140 kV, and the 90th percentile R{sub K} values ranged from 0.64 at 80 kV to 0.78 at 140 kV. The average R{sub K} for the 25 Rando organs at 120 kV was 0.61 {+-} 0.08. Average R{sub K} values in the head, chest, and abdomen showed little variation. Relative to R{sub K} values in the head, chest, and abdomen obtained at 120 kV, R{sub K} values were about 12% lower in the pelvis and about 58% higher in the cervical spine region. Average R{sub K} values were about 6% higher on the Siemens Sensation 16 scanner than the GE LightSpeed Ultra. Reducing the x-ray tube voltage from 120 kV to 80 kV resulted in an average reduction in R{sub K} value of 34%, whereas increasing the x-ray tube voltage to 140 kV increased the average R{sub K} value by 9%. Conclusions: In-patient to isocenter relative KERMA values in Rando phantom can be used to estimate organ doses in similar sized adults undergoing CT examinations from easily measured air KERMA values at the

  20. 68Ga-PSMA PET/CT Uptake in Intramuscular Myxoma Imitates Prostate Cancer Metastasis.

    PubMed

    Zacho, Helle D; Nielsen, Julie B; Dettmann, Katja; Hjulskov, Sonja H; Petersen, Lars J

    2017-03-31

    Ga-PSMA PET/CT is becoming the most promising imaging modality for detecting recurrent prostate cancer. The modality has the advantage of being able to detect recurrent disease, even at very low prostate-specific antigen levels. However, several studies report Ga-PSMA uptake in tissue unrelated to prostate cancer. We present a 74-year-old man who underwent Ga-PSMA PET/CT for recurrent prostate cancer 5 years after radical prostatectomy. The Ga-PSMA PET/CT showed an intramuscular lesion with increased PSMA uptake in the left vastus medialis muscle. The lesion was surgically removed, and histopathology found it to be an intramuscular myxoma that showed immunohistochemical PSMA expression.

  1. Intraorbital Encephalocele Presenting with Exophthalmos and Orbital Dystopia : CT and MRI Findings

    PubMed Central

    Gunduz, Yasemin; Yaldiz, Can; Aksoy, Yakup Ersel

    2015-01-01

    A 15-year-old female patient with progressive pulsatile exophthalmos caused by intraorbital encephalocele was evaluated with computed tomography (CT) and magnetic resonance imaging (MRI) in our clinic. She had no history of trauma or reconstructive surgery. When she was a little girl, she had undergone surgery for congenital glaucoma on the right eye. On the three-dimensional image of CT, a hypoplasic bone defect was observed in the greater wing of the right sphenoid bone. MRI and CT scan showed herniation through this defect of the arachnoid membrane and protruded cerebral tissue into the right orbita. Intraorbital encephalocele is an important entity that can cause pulsatile exophthalmos and blindness. PMID:25674346

  2. CT brain findings in a patient with elevated brain cesium levels.

    PubMed

    Khangure, Simon R; Williams, Eric S; Welman, Christopher J

    2013-12-01

    We describe the CT findings in the brain of a woman with pathologically proven elevated levels of blood and tissue cesium. The 42-year-old woman had been receiving cesium chloride as a non-mainstream treatment for metastatic breast carcinoma. She presented to hospital following a seizure, and died 48 hours after admission. A brain CT performed on hospital admission showed a diffuse increase in attenuation of brain parenchyma. Autopsy revealed elevated levels of cesium in blood and solid organs including the brain. We hypothesize that the imaging findings are attributable to the abnormally elevated level of brain cesium at the time of the CT scan. To our knowledge, this is the first reported case of this imaging finding.

  3. Cytomegalovirus pneumonia in transplant patients: CT findings

    SciTech Connect

    Eun-Young Kang; Patz, E.F. Jr.; Mueller, N.L.

    1996-03-01

    Our goal was to assess the CT findings of cytomegalovirus (CMV) pneumonia in transplant patients. The study included 10 transplant patients who had chest CT scan and pathologically proven isolated pulmonary CMV infection. Five patients had bone marrow transplant and five had solid organ transplant. The CT scans were retrospectively reviewed for pattern and distribution of disease and the CT findings compared with the findings on open lung biopsy (n = 9) and autopsy (n = 1). Nine of 10 patients had parenchymal abnormalities apparent at CT and I had normal CT scans. The findings in the nine patients included small nodules (n = 6), consolidation (n = 4), ground-glass attenuation (n = 4), and irregular lines (n = 1). The nodules had a bilateral and symmetric distribution and involved all lung zones. The consolidation was most marked in the lower lung zones. The CT findings of CMV pneumonia in transplant patients are heterogeneous. The most common patterns include small nodules and areas of consolidation. 13 refs., 4 figs., 1 tab.

  4. CT-Based Attenuation Correction in Brain SPECT/CT Can Improve the Lesion Detectability of Voxel-Based Statistical Analyses

    PubMed Central

    Kato, Hiroki; Shimosegawa, Eku; Fujino, Koichi; Hatazawa, Jun

    2016-01-01

    Background Integrated SPECT/CT enables non-uniform attenuation correction (AC) using built-in CT instead of the conventional uniform AC. The effect of CT-based AC on voxel-based statistical analyses of brain SPECT findings has not yet been clarified. Here, we assessed differences in the detectability of regional cerebral blood flow (CBF) reduction using SPECT voxel-based statistical analyses based on the two types of AC methods. Subjects and Methods N-isopropyl-p-[123I]iodoamphetamine (IMP) CBF SPECT images were acquired for all the subjects and were reconstructed using 3D-OSEM with two different AC methods: Chang’s method (Chang’s AC) and the CT-based AC method. A normal database was constructed for the analysis using SPECT findings obtained for 25 healthy normal volunteers. Voxel-based Z-statistics were also calculated for SPECT findings obtained for 15 patients with chronic cerebral infarctions and 10 normal subjects. We assumed that an analysis with a higher specificity would likely produce a lower mean absolute Z-score for normal brain tissue, and a more sensitive voxel-based statistical analysis would likely produce a higher absolute Z-score for in old infarct lesions, where the CBF was severely decreased. Results The inter-subject variation in the voxel values in the normal database was lower using CT-based AC, compared with Chang’s AC, for most of the brain regions. The absolute Z-score indicating a SPECT count reduction in infarct lesions was also significantly higher in the images reconstructed using CT-based AC, compared with Chang’s AC (P = 0.003). The mean absolute value of the Z-score in the 10 intact brains was significantly lower in the images reconstructed using CT-based AC than in those reconstructed using Chang’s AC (P = 0.005). Conclusions Non-uniform CT-based AC by integrated SPECT/CT significantly improved sensitivity and the specificity of the voxel-based statistical analyses for regional SPECT count reductions, compared with

  5. Automatic anatomy recognition in whole-body PET/CT images

    SciTech Connect

    Wang, Huiqian; Udupa, Jayaram K. Odhner, Dewey; Tong, Yubing; Torigian, Drew A.; Zhao, Liming

    2016-01-15

    , to bring performance to the level achieved on diagnostic CT and MR images in body-region-wise approaches. The intermodality approach fosters the use of already existing fuzzy models, previously created from diagnostic CT images, on PET/CT and other derived images, thus truly separating the modality-independent object assembly anatomy from modality-specific tissue property portrayal in the image. Results: Key ways of combining the above three basic ideas lead them to 15 different strategies for recognizing objects in PET/CT images. Utilizing 50 diagnostic CT image data sets from the thoracic and abdominal body regions and 16 whole-body PET/CT image data sets, the authors compare the recognition performance among these 15 strategies on 18 objects from the thorax, abdomen, and pelvis in object localization error and size estimation error. Particularly on texture membership images, object localization is within three voxels on whole-body low-dose CT images and 2 voxels on body-region-wise low-dose images of known true locations. Surprisingly, even on direct body-region-wise PET images, localization error within 3 voxels seems possible. Conclusions: The previous body-region-wise approach can be extended to whole-body torso with similar object localization performance. Combined use of image texture and intensity property yields the best object localization accuracy. In both body-region-wise and whole-body approaches, recognition performance on low-dose CT images reaches levels previously achieved on diagnostic CT images. The best object recognition strategy varies among objects; the proposed framework however allows employing a strategy that is optimal for each object.

  6. Repeat CT imaging and replanning during the course of IMRT for head-and-neck cancer

    SciTech Connect

    Hansen, Eric K.; Bucci, M. Kara; Quivey, Jeanne M.; Weinberg, Vivian; Xia Ping . E-mail: xia@radonc17.ucsf.edu

    2006-02-01

    Purpose: Many patients with head-and-neck (H and N) cancer have tumor shrinkage and/or weight loss during the course of radiotherapy. We conducted this retrospective study to determine the dosimetric effects of repeat computed tomography (CT) imaging and replanning during the course of intensity-modulated radiotherapy (IMRT) on both normal tissues and target volumes. Methods and Materials: A retrospective chart review identified 13 patients with H and N cancer treated with IMRT who had repeat CT imaging and replanning during the course of radiotherapy. The first IMRT plan for each patient was generated based on the original planning CT scan acquired before the start of treatment. Because of tumor shrinkage or weight loss during radiotherapy, a second CT scan was acquired, and a new plan was generated and used to complete the course of IMRT. CT-CT fusion was used to correct patient positioning differences between the scans. By using a commercial inverse IMRT planning system, a hybrid IMRT plan was generated for each patient by applying the beam configurations of the first IMRT plan (including the intensity profile of each beam) to the anatomy of the second CT scan. The dose-volume histograms of the actual and hybrid IMRT plans were compared using analysis of variance methods for repeated measures. Results: All patients had locally advanced, nonmetastatic Stage III or IV disease, including 6 nasopharynx, 6 oropharynx, and 1 unknown primary site. All patients were treated with concurrent platinum-based chemotherapy. When replanning vs. not replanning was compared, the hybrid IMRT plans (without replanning) demonstrated reduced doses to target volumes and increased doses to critical structures. The doses to 95% (D{sub 95}) of the planning target volumes of the gross tumor volume (PTV{sub GTV}) and the clinical target volume (PTV{sub CTV}) were reduced in 92% of patients, by 0.8-6.3 Gy (p = 0.02) and 0.2-7.4 Gy (p = 0.003), respectively. The maximum dose (D{sub max}) to

  7. Doses metrics and patient age in CT.

    PubMed

    Huda, Walter; Tipnis, Sameer V

    2016-03-01

    The aim of this study was to investigate how effective dose and size-specific dose estimate (SSDE) change with patient age (size) for routine head and abdominal/pelvic CT examinations. Heads and abdomens of patients were modelled as a mass-equivalent cylinder of water corresponding to the patient 'effective diameter'. Head CT scans were performed at CTDIvol(S) of 40 mGy, and abdominal CT scans were performed at CTDIvol(L) of 10 mGy. Values of SSDE were obtained using conversion factors in AAPM Task Group Report 204. Age-specific scan lengths for head and abdominal CT scans obtained from the authors' clinical practice were used to estimate the dose-length product for each CT examination. Effective doses were calculated from previously published age- and sex-specific E/DLP conversion factors, based on ICRP 103 organ-weighting factors. For head CT examinations, the scan length increased from 15 cm in a newborn to 20 cm in adults, and for an abdominal/pelvic CT, the scan length increased from 20 cm in a newborn to 45 cm in adults. For head CT scans, SSDE ranged from 37.2 mGy in adults to 48.8 mGy in a newborn, an increase of 31 %. The corresponding head CT effective doses range from 1.4 mSv in adults to 5.2 mSv in a newborn, an increase of 270 %. For abdomen CT scans, SSDE ranged from 13.7 mGy in adults to 23.0 mGy in a newborn, an increase of 68 %. The corresponding abdominal CT effective doses ranged from 6.3 mSv in adults to 15.4 mSv in a newborn, an increase of 140 %. SSDE increases much less than effective dose in paediatric patients compared with adults because it does not account for scan length or scattered radiation. Size- and age-specific effective doses better quantify the total radiation received by patients in CT by explicitly accounting for all organ doses, as well as their relative radio sensitivity.

  8. [The use of CT in meniscopathy].

    PubMed

    Tellkamp, H; Klein, W; Rosenkranz, G; Köhler, K

    1988-12-01

    The results of CT examination of meniscopathies in 54 patients, most of them competitive athletes, are presented. CT has an overall accuracy of about 90 per cent and can hence be used for diagnosing a lesion of the meniscus with a reasonable amount of safety, while being rapid and avoiding unnecessary exposure to stress. This method, therefore, should be a focal point of the imaging methods and thus be placed between the specialist doctor's findings and possible surgery. The pros and cons of CT compared with other imaging methods are discussed.

  9. Cine CT technique for dynamic airway studies

    SciTech Connect

    Ell, S.R.; Jolles, H.; Keyes, W.D.; Galvin, J.R.

    1985-07-01

    The advent of cine CT scanning with its 50-msec data acquisition time promises a much wider range of dynamic CT studies. The authors describe a method for dynamic evaluation of the extrathoracic airway, which they believe has considerable potential application in nonfixed upper-airway disease, such as sleep apnea and stridor of unknown cause. Conventional CT is limited in such studies by long data acquisition time and can be used to study only prolonged maneuvers such as phonation. Fluoroscopy and digital subtraction studies are limited by relatively high radiation dose and inability to image all wall motions simultaneously.

  10. Informatics in radiology: dual-energy electronic cleansing for fecal-tagging CT colonography.

    PubMed

    Cai, Wenli; Kim, Se Hyung; Lee, June-Goo; Yoshida, Hiroyuki

    2013-05-01

    Electronic cleansing (EC) is an emerging technique for the removal of tagged fecal materials at fecal-tagging computed tomographic (CT) colonography. However, existing EC methods may generate various types of artifacts that severely impair the quality of the cleansed CT colonographic images. Dual-energy fecal-tagging CT colonography is regarded as a next-generation imaging modality. EC that makes use of dual-energy fecal-tagging CT colonographic images promises to be effective in reducing cleansing artifacts by means of applying the material decomposition capability of dual-energy CT. The dual-energy index (DEI), which is calculated from the relative change in the attenuation values of a material at two different photon energies, is a reliable and effective indicator for differentiating tagged fecal materials from various types of tissues on fecal-tagging CT colonographic images. A DEI-based dual-energy EC scheme uses the DEI to help differentiate the colonic lumen-including the luminal air, tagged fecal materials, and air-tagging mixture-from the colonic soft-tissue structures, and then segments the entire colonic lumen for cleansing of the tagged fecal materials. As a result, dual-energy EC can help identify partial-volume effects in the air-tagging mixture and inhomogeneous tagging in residual fecal materials, the major causes of EC artifacts. This technique has the potential to significantly improve the quality of EC and promises to provide images of a cleansed colon that are free of the artifacts commonly observed with conventional single-energy EC methods.

  11. Microstructure analysis of the secondary pulmonary lobules by 3D synchrotron radiation CT

    NASA Astrophysics Data System (ADS)

    Fukuoka, Y.; Kawata, Y.; Niki, N.; Umetani, K.; Nakano, Y.; Ohmatsu, H.; Moriyama, N.; Itoh, H.

    2014-03-01

    Recognition of abnormalities related to the lobular anatomy has become increasingly important in the diagnosis and differential diagnosis of lung abnormalities at clinical routines of CT examinations. This paper aims a 3-D microstructural analysis of the pulmonary acinus with isotropic spatial resolution in the range of several micrometers by using micro CT. Previously, we demonstrated the ability of synchrotron radiation micro CT (SRμCT) using offset scan mode in microstructural analysis of the whole part of the secondary pulmonary lobule. In this paper, we present a semiautomatic method to segment the acinar and subacinar airspaces from the secondary pulmonary lobule and to track small vessels running inside alveolar walls in human acinus imaged by the SRμCT. The method beains with and segmentation of the tissues such as pleural surface, interlobular septa, alveola wall, or vessel using a threshold technique and 3-D connected component analysis. 3-D air space are then conustructed separated by tissues and represented branching patterns of airways and airspaces distal to the terminal bronchiole. A graph-partitioning approach isolated acini whose stems are interactively defined as the terminal bronchiole in the secondary pulmonary lobule. Finally, we performed vessel tracking using a non-linear sate space which captures both smoothness of the trajectories and intensity coherence along vessel orientations. Results demonstrate that the proposed method can extract several acinar airspaces from the 3-D SRμCT image of secondary pulmonary lobule and that the extracted acinar airspace enable an accurate quantitative description of the anatomy of the human acinus for interpretation of the basic unit of pulmonary structure and function.

  12. Informatics in Radiology: Dual-Energy Electronic Cleansing for Fecal-Tagging CT Colonography

    PubMed Central

    Kim, Se Hyung; Lee, June-Goo; Yoshida, Hiroyuki

    2013-01-01

    Electronic cleansing (EC) is an emerging technique for the removal of tagged fecal materials at fecal-tagging computed tomographic (CT) colonography. However, existing EC methods may generate various types of artifacts that severely impair the quality of the cleansed CT colonographic images. Dual-energy fecal-tagging CT colonography is regarded as a next-generation imaging modality. EC that makes use of dual-energy fecal-tagging CT colonographic images promises to be effective in reducing cleansing artifacts by means of applying the material decomposition capability of dual-energy CT. The dual-energy index (DEI), which is calculated from the relative change in the attenuation values of a material at two different photon energies, is a reliable and effective indicator for differentiating tagged fecal materials from various types of tissues on fecal-tagging CT colonographic images. A DEI-based dual-energy EC scheme uses the DEI to help differentiate the colonic lumen—including the luminal air, tagged fecal materials, and air-tagging mixture—from the colonic soft-tissue structures, and then segments the entire colonic lumen for cleansing of the tagged fecal materials. As a result, dual-energy EC can help identify partial-volume effects in the air-tagging mixture and inhomogeneous tagging in residual fecal materials, the major causes of EC artifacts. This technique has the potential to significantly improve the quality of EC and promises to provide images of a cleansed colon that are free of the artifacts commonly observed with conventional single-energy EC methods. © RSNA, 2013 PMID:23479680

  13. MicroPET/CT Colonoscopy in long-lived Min mouse using NM404

    NASA Astrophysics Data System (ADS)

    Christensen, Matthew B.; Halberg, Richard B.; Schutten, Melissa M.; Weichert, Jamey P.

    2009-02-01

    Colon cancer is a leading cause of death in the US, even though many cases are preventable if tumors are detected early. One technique to promote screening is Computed Tomography Colonography (CTC). NM404 is a second generation phospholipid ether analogue which has demonstrated selective uptake and prolonged retention in 43/43 types of malignant tumors but not inflammatory sites or premalignant lesions. The purpose of this experiment was to evaluate (SWR x B6 )F1.Min mice as a preclinical model to test MicroPET/CT dual modality virtual colonoscopy. Each animal was given an IV injection of 124I-NM404 (100 uCi) 24, 48 and 96 hours prior to scanning on a dedicated microPET/CT system. Forty million counts were histogrammed in 3D and reconstructed using an OSEM 2D algorithm. Immediately after PET acquisition, a 93 m volumetric CT was acquired at 80 kVp, 800 uA and 350 ms exposures. Following CT, the mouse was sacrificed. The entire intestinal tract was excised, washed, insufflated, and scanned ex vivo A total of eight tissue samples from the small intestine were harvested: 5 were benign adenomas, 2 were malignant adenocarcinomas, and 1 was a Peyer's patch (lymph tissue) . The sites of these samples were positioned on CT and PET images based on morphological cues and the distance from the anus. Only 1/8 samples showed tracer uptake. several hot spots in the microPET image were not chosen for histology. (SWR x B6)F1.Min mice develop benign and malignant tumors, making this animal model a strong candidate for future dual modality microPET/CT virtual colonography studies.

  14. Patient-specific radiation dose and cancer risk estimation in CT: Part II. Application to patients

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P.

    2011-01-15

    patients. However, the overall risk of cancer incidence attributable to the CT examination was much higher for the newborn (2.4 in 1000) than for the teenager (0.7 in 1000). For the two pediatric-aged patients in our study, CTDI{sub vol} underestimated dose to large organs in the scan coverage by 30%-48%. The effective dose derived from DLP using published conversion coefficients differed from that calculated using patient-specific organ dose values by -57% to 13%, when the tissue weighting factors of ICRP 60 were used, and by -63% to 28%, when the tissue weighting factors of ICRP 103 were used. Conclusions: It is possible to estimate patient-specific radiation dose and cancer risk from CT examinations by combining a validated Monte Carlo program with patient-specific anatomical models that are derived from the patients' clinical CT data and supplemented by transformed models of reference adults. With the construction of a large library of patient-specific computer models encompassing patients of all ages and weight percentiles, dose and risk can be estimated for any patient prior to or after a CT examination. Such information may aid in decisions for image utilization and can further guide the design and optimization of CT technologies and scan protocols.

  15. Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography

    PubMed Central

    Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

    2016-01-01

    Objectives: Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Materials and Methods: Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). Results: There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. Conclusions: CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations. PMID:27928239

  16. Suppression of high-density artifacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

    NASA Astrophysics Data System (ADS)

    Baissalov, Roustem; Sandison, George A.; Donnelly, Bryan J.; Saliken, John C.; Muldrew, Ken; Rewcastle, John C.

    2000-06-01

    Image guidance of cryotherapy is usually performed using ultrasound or x-ray CT. Despite the ability of CT to display the full 3D structure of the iceball, including frozen and unfrozen regions, the quality of the images is compromised by the presence of high density streak artifacts. To suppress these artifacts we applied Temporal Digital Subtraction (TDS). This TDS method has the added advantage of improving the gray scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high density artifacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced content of the artifacts. This TDS can be used in x-ray CT assisted cryotherapy to significantly suppress or eliminate high density x-ray CT streak artifacts by digitally processing x-ray CT images. Applying TDS in cryotherapy will facilitate estimation of the amount and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent.

  17. Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: A digital phantom study

    SciTech Connect

    Bernatowicz, K. Knopf, A.; Lomax, A.; Keall, P.; Kipritidis, J.; Mishra, P.

    2015-01-15

    Purpose: Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CT can significantly reduce lung imaging artifacts. Methods: Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) “conventional” 4D CT that uses a constant imaging and couch-shift frequency, (ii) “beam paused” 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) “respiratory-gated” 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm{sup 3} spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Results

  18. Dynamic FDG PET/CT imaging with diuresis demonstrates an enterovesical fistula in a lymphoma patient with repeated colon diverticulitis.

    PubMed

    Kao, Pan-Fu; Ting, Wen-Chien; Hsiao, Pei-Ching; Kao, Yu-Lin; Chang, Pai-Jung; Lee, Jong-Kang

    2013-04-01

    A 43-year-old male patient with follicular B-cell lymphoma was referred for a FDG PET/CT scan due to severe left lower abdominal pain to rule out recurrent cancer. These FDG PET/CT images and previous FDG PET/CT images 5 months ago both revealed an air bubble in the urinary bladder on the CT images. He had a recurrent urinary tract infection history for 6 months. A list-mode dynamic data acquisition with diuresis intravenous injection revealed linear FDG activity extending from the upper-left portion of the bladder to a soft tissue mass in the lower-left pelvic region. An enterovesical fistula was confirmed by surgery.

  19. Characterization of a prototype tabletop x-ray CT breast imaging system

    NASA Astrophysics Data System (ADS)

    O'Connor, J. Michael; Glick, Stephen J.; Gong, Xing; Didier, Clay; Mah'd, Mufeed

    2007-03-01

    Planar X-ray mammography is the standard medical imaging modality for the early detection of breast cancer. Based on advancements in digital flat-panel detector technology, dedicated x-ray computed tomography (CT) mammography is a modality under investigation that offers the potential for improved breast tumor imaging. We have implemented a prototype half cone-beam CT breast imaging system that utilizes an indirect flat-panel detector. This prototype can be used to explore and evaluate the effect of varying acquisition and reconstruction parameters on image quality. This report describes our system and characterizes the performance of the system through the analysis of Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS). All CT reconstructions were made using Feldkamp's filtered backprojection algorithm. The 3D MTF was determined by the analysis of the plane spread function (PlSF) derived from the surface spread function (SSF) of reconstructed 6.3mm spheres. 3D NPS characterization was performed through the analysis of a 3D volume extracted from zero-mean CT noise of air reconstructions. The effect of varying locations on MTF and the effect of different Butterworth filter cutoff frequencies on NPS are reported. Finally, we present CT images of mastectomy excised breast tissue. Breast specimen images were acquired on our CTMS using an x-ray technique similar to the one used during performance characterization. Specimen images demonstrate the inherent CT capability to reduce the masking effect of anatomical noise. Both the quantitative system characterization and the breast specimen images continue to reinforce the hope that dedicated flat-panel detector, x-ray cone-beam CT will eventually provide enhanced breast cancer detection capability.

  20. Lymph node detection in IASLC-defined zones on PET/CT images

    NASA Astrophysics Data System (ADS)

    Song, Yihua; Udupa, Jayaram K.; Odhner, Dewey; Tong, Yubing; Torigian, Drew A.

    2016-03-01

    Lymph node detection is challenging due to the low contrast between lymph nodes as well as surrounding soft tissues and the variation in nodal size and shape. In this paper, we propose several novel ideas which are combined into a system to operate on positron emission tomography/ computed tomography (PET/CT) images to detect abnormal thoracic nodes. First, our previous Automatic Anatomy Recognition (AAR) approach is modified where lymph node zones predominantly following International Association for the Study of Lung Cancer (IASLC) specifications are modeled as objects arranged in a hierarchy along with key anatomic anchor objects. This fuzzy anatomy model built from diagnostic CT images is then deployed on PET/CT images for automatically recognizing the zones. A novel globular filter (g-filter) to detect blob-like objects over a specified range of sizes is designed to detect the most likely locations and sizes of diseased nodes. Abnormal nodes within each automatically localized zone are subsequently detected via combined use of different items of information at various scales: lymph node zone model poses found at recognition indicating the geographic layout at the global level of node clusters, g-filter response which hones in on and carefully selects node-like globular objects at the node level, and CT and PET gray value but within only the most plausible nodal regions for node presence at the voxel level. The models are built from 25 diagnostic CT scans and refined for an object hierarchy based on a separate set of 20 diagnostic CT scans. Node detection is tested on an additional set of 20 PET/CT scans. Our preliminary results indicate node detection sensitivity and specificity at around 90% and 85%, respectively.

  1. Performance analysis of model based iterative reconstruction with dictionary learning in transportation security CT

    NASA Astrophysics Data System (ADS)

    Haneda, Eri; Luo, Jiajia; Can, Ali; Ramani, Sathish; Fu, Lin; De Man, Bruno

    2016-05-01

    In this study, we implement and compare model based iterative reconstruction (MBIR) with dictionary learning (DL) over MBIR with pairwise pixel-difference regularization, in the context of transportation security. DL is a technique of sparse signal representation using an over complete dictionary which has provided promising results in image processing applications including denoising,1 as well as medical CT reconstruction.2 It has been previously reported that DL produces promising results in terms of noise reduction and preservation of structural details, especially for low dose and few-view CT acquisitions.2 A distinguishing feature of transportation security CT is that scanned baggage may contain items with a wide range of material densities. While medical CT typically scans soft tissues, blood with and without contrast agents, and bones, luggage typically contains more high density materials (i.e. metals and glass), which can produce severe distortions such as metal streaking artifacts. Important factors of security CT are the emphasis on image quality such as resolution, contrast, noise level, and CT number accuracy for target detection. While MBIR has shown exemplary performance in the trade-off of noise reduction and resolution preservation, we demonstrate that DL may further improve this trade-off. In this study, we used the KSVD-based DL3 combined with the MBIR cost-minimization framework and compared results to Filtered Back Projection (FBP) and MBIR with pairwise pixel-difference regularization. We performed a parameter analysis to show the image quality impact of each parameter. We also investigated few-view CT acquisitions where DL can show an additional advantage relative to pairwise pixel difference regularization.

  2. Reproducibility and variability of very low dose hepatic perfusion CT in metastatic liver disease

    PubMed Central

    Topcuoğlu, Osman Melih; Karçaaltıncaba, Muşturay; Akata, Deniz; Özmen, Mustafa Nasuh

    2016-01-01

    PURPOSE We aimed to determine the intra- and interobserver agreement on the software analysis of very low dose hepatic perfusion CT (pCT). METHODS A total of 53 pCT examinations were obtained from 21 patients (16 men, 5 women; mean age, 60.4 years) with proven liver metastasis from various primary cancers. The pCT examinations were analyzed by two readers independently and perfusion parameters were noted for whole liver, whole metastasis, metastasis wall, and normal-looking liver (liver tissue without metastasis) in regions of interest (ROIs). Readers repeated the analysis after an interval of one month. Intra- and interobserver agreements were assessed with intraclass correlation coefficients (ICC) and Bland-Altman statistics. RESULTS The mean ICCs of all ROIs between readers were 0.91, 0.93, 0.86, 0.45, 0.53, and 0.66 for blood flow (BF), blood volume (BV), permeability, arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI), respectively. The mean ICCs of all ROIs between readings were 0.86, 0.91, 0.81, 0.53, 0.56, and 0.71 for BF, BV, permeability, ALP, PVP, and HPI, respectively. There was greater agreement on the parameters measured for the whole metastasis than on the parameters measured for the metastasis wall. The effective dose of all perfusion CT studies was 2.9 mSv. CONCLUSION There is greater intra- and interobserver agreement for BF and BV than for permeability, ALP, PVP, and HPI at very low dose hepatic pCT. Permeability, ALP, PVP, and HPI parameters cannot be used in clinical practice for hepatic pCT with an effective dose of 2.9 mSv. PMID:27759566

  3. Segmentation-free empirical beam hardening correction for CT

    SciTech Connect

    Schüller, Sören; Sawall, Stefan; Stannigel, Kai; Hülsbusch, Markus; Ulrici, Johannes; Hell, Erich; Kachelrieß, Marc

    2015-02-15

    Purpose: The polychromatic nature of the x-ray beams and their effects on the reconstructed image are often disregarded during standard image reconstruction. This leads to cupping and beam hardening artifacts inside the reconstructed volume. To correct for a general cupping, methods like water precorrection exist. They correct the hardening of the spectrum during the penetration of the measured object only for the major tissue class. In contrast, more complex artifacts like streaks between dense objects need other techniques of correction. If using only the information of one single energy scan, there are two types of corrections. The first one is a physical approach. Thereby, artifacts can be reproduced and corrected within the original reconstruction by using assumptions in a polychromatic forward projector. These assumptions could be the used spectrum, the detector response, the physical attenuation and scatter properties of the intersected materials. A second method is an empirical approach, which does not rely on much prior knowledge. This so-called empirical beam hardening correction (EBHC) and the previously mentioned physical-based technique are both relying on a segmentation of the present tissues inside the patient. The difficulty thereby is that beam hardening by itself, scatter, and other effects, which diminish the image quality also disturb the correct tissue classification and thereby reduce the accuracy of the two known classes of correction techniques. The herein proposed method works similar to the empirical beam hardening correction but does not require a tissue segmentation and therefore shows improvements on image data, which are highly degraded by noise and artifacts. Furthermore, the new algorithm is designed in a way that no additional calibration or parameter fitting is needed. Methods: To overcome the segmentation of tissues, the authors propose a histogram deformation of their primary reconstructed CT image. This step is essential for the

  4. CT thermometry for cone-beam CT guided ablation

    NASA Astrophysics Data System (ADS)

    DeStefano, Zachary; Abi-Jaoudeh, Nadine; Li, Ming; Wood, Bradford J.; Summers, Ronald M.; Yao, Jianhua

    2016-03-01

    Monitoring temperature during a cone-beam CT (CBCT) guided ablation procedure is important for prevention of over-treatment and under-treatment. In order to accomplish ideal temperature monitoring, a thermometry map must be generated. Previously, this was attempted using CBCT scans of a pig shoulder undergoing ablation.1 We are extending this work by using CBCT scans of real patients and incorporating more processing steps. We register the scans before comparing them due to the movement and deformation of organs. We then automatically locate the needle tip and the ablation zone. We employ a robust change metric due to image noise and artifacts. This change metric takes windows around each pixel and uses an equation inspired by Time Delay Analysis to calculate the error between windows with the assumption that there is an ideal spatial offset. Once the change map is generated, we correlate change data with measured temperature data at the key points in the region. This allows us to transform our change map into a thermal map. This thermal map is then able to provide an estimate as to the size and temperature of the ablation zone. We evaluated our procedure on a data set of 12 patients who had a total of 24 ablation procedures performed. We were able to generate reasonable thermal maps with varying degrees of accuracy. The average error ranged from 2.7 to 16.2 degrees Celsius. In addition to providing estimates of the size of the ablation zone for surgical guidance, 3D visualizations of the ablation zone and needle are also produced.

  5. Automatic lung tumor segmentation on PET/CT images using fuzzy Markov random field model.

    PubMed

    Guo, Yu; Feng, Yuanming; Sun, Jian; Zhang, Ning; Lin, Wang; Sa, Yu; Wang, Ping

    2014-01-01

    The combination of positron emission tomography (PET) and CT images provides complementary functional and anatomical information of human tissues and it has been used for better tumor volume definition of lung cancer. This paper proposed a robust method for automatic lung tumor segmentation on PET/CT images. The new method is based on fuzzy Markov random field (MRF) model. The combination of PET and CT image information is achieved by using a proper joint posterior probability distribution of observed features in the fuzzy MRF model which performs better than the commonly used Gaussian joint distribution. In this study, the PET and CT simulation images of 7 non-small cell lung cancer (NSCLC) patients were used to evaluate the proposed method. Tumor segmentations with the proposed method and manual method by an experienced radiation oncologist on the fused images were performed, respectively. Segmentation results obtained with the two methods were similar and Dice's similarity coefficient (DSC) was 0.85 ± 0.013. It has been shown that effective and automatic segmentations can be achieved with this method for lung tumors which locate near other organs with similar intensities in PET and CT images, such as when the tumors extend into chest wall or mediastinum.

  6. Simulation of mammograms and tomosynthesis imaging with cone beam breast CT images

    NASA Astrophysics Data System (ADS)

    Han, Tao; Shaw, Chris C.; Chen, Lingyun; Lai, Chao-jen; Liu, Xinming; Wang, Tianpeng

    2008-03-01

    The use of mammography techniques for the screening and diagnosis of breast cancers has been limited by the overlapping of cancer symptoms with normal tissue structures. To overcome this problem, two methods have been developed and actively investigated recently: digital tomosynthesis mammography and cone beam breast CT. Comparison study with these three techniques will be helpful to understand their difference and further might be supervise the direction of breast imaging. This paper describes and discusses about a technique using a general-purpose PC cluster to develop a parallel computer simulation model to simulate mammograms and tomosynthesis imaging with cone beam CT images of a mastectomy breast specimen. The breast model used in simulating mammography and tomosynthesis was developed by re-scaling the CT numbers of cone beam CT images from 80kVp to 20 kev. The compression of breast was simulated by deformation of the breast model. Re-projection software with parallel computation was developed and used to compute projection images of this simulated compressed breast for a stationary detector and a linearly shifted x-ray source. The resulting images were then used to reconstruct tomosynthesis mammograms using shift-and-add algorithms. It was found that MCs in cone beam CT images were not visible in regular mammograms but faintly visible in tomosynthesis images. The scatter signal and noise property needs to be simulated and incorporated in the future.

  7. Geometry-constraint-scan imaging for in-line phase contrast micro-CT.

    PubMed

    Fu, Jian; Yu, Guangyuan; Fan, Dekai

    2014-01-01

    X-ray phase contrast computed tomography (CT) uses the phase shift that x-rays undergo when passing through matter, rather than their attenuation, as the imaging signal and may provide better image quality in soft-tissue and biomedical materials with low atomic number. Here a geometry-constraint-scan imaging technique for in-line phase contrast micro-CT is reported. It consists of two circular-trajectory scans with x-ray detector at different positions, the phase projection extraction method with the Fresnel free-propagation theory and the filter back-projection reconstruction algorithm. This method removes the contact-detector scan and the pure phase object assumption in classical in-line phase contrast Micro-CT. Consequently it relaxes the experimental conditions and improves the image contrast. This work comprises a numerical study of this technique and its experimental verification using a biomedical composite dataset measured at an x-ray tube source Micro-CT setup. The numerical and experimental results demonstrate the validity of the presented method. It will be of interest for a wide range of in-line phase contrast Micro-CT applications in biology and medicine.

  8. Automatic Lung Tumor Segmentation on PET/CT Images Using Fuzzy Markov Random Field Model

    PubMed Central

    Guo, Yu; Feng, Yuanming; Sun, Jian; Lin, Wang; Sa, Yu; Wang, Ping

    2014-01-01

    The combination of positron emission tomography (PET) and CT images provides complementary functional and anatomical information of human tissues and it has been used for better tumor volume definition of lung cancer. This paper proposed a robust method for automatic lung tumor segmentation on PET/CT images. The new method is based on fuzzy Markov random field (MRF) model. The combination of PET and CT image information is achieved by using a proper joint posterior probability distribution of observed features in the fuzzy MRF model which performs better than the commonly used Gaussian joint distribution. In this study, the PET and CT simulation images of 7 non-small cell lung cancer (NSCLC) patients were used to evaluate the proposed method. Tumor segmentations with the proposed method and manual method by an experienced radiation oncologist on the fused images were performed, respectively. Segmentation results obtained with the two methods were similar and Dice's similarity coefficient (DSC) was 0.85 ± 0.013. It has been shown that effective and automatic segmentations can be achieved with this method for lung tumors which locate near other organs with similar intensities in PET and CT images, such as when the tumors extend into chest wall or mediastinum. PMID:24987451

  9. FDG PET/CT of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease.

    PubMed

    Paes, Fabio M; Kalkanis, Dimitrios G; Sideras, Panagiotis A; Serafini, Aldo N

    2010-01-01

    The term extranodal disease refers to lymphomatous infiltration of anatomic sites other than the lymph nodes. Almost any organ can be affected by lymphoma, with the most common extranodal sites of involvement being the stomach, spleen, Waldeyer ring, central nervous system, lung, bone, and skin. The prevalence of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease has increased in the past decade. The imaging characteristics of extranodal involvement can be subtle or absent at conventional computed tomography (CT). Imaging of tumor metabolism with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) has facilitated the identification of affected extranodal sites, even when CT has demonstrated no lesions. More recently, hybrid PET/CT has become the standard imaging modality for initial staging, follow-up, and treatment response assessment in patients with lymphoma and has proved superior to CT in these settings. Certain PET/CT patterns are suggestive of extranodal disease and can help differentiate tumor from normal physiologic FDG activity, particularly in the mucosal tissues, bone marrow, and organs of the gastrointestinal tract. Familiarity with the different extranodal manifestations in various locations is critical for correct image interpretation. In addition, a knowledge of the differences in FDG avidity among the histologic subtypes of lymphoma, appropriate timing of scanning after therapeutic interventions, and use of techniques to prevent brown fat uptake are essential for providing the oncologist with accurate information.

  10. Intraparenchymal hemorrhage segmentation from clinical head CT of patients with traumatic brain injury

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; Wilkes, Sean; Diaz-Arrastia, Ramon; Butman, John A.; Pham, Dzung L.

    2015-03-01

    Quantification of hemorrhages in head computed tomography (CT) images from patients with traumatic brain injury (TBI) has potential applications in monitoring disease progression and better understanding of the patho-physiology of TBI. Although manual segmentations can provide accurate measures of hemorrhages, the processing time and inter-rater variability make it infeasible for large studies. In this paper, we propose a fully automatic novel pipeline for segmenting intraparenchymal hemorrhages (IPH) from clinical head CT images. Unlike previous methods of model based segmentation or active contour techniques, we rely on relevant and matching examples from already segmented images by trained raters. The CT images are first skull-stripped. Then example patches from an "atlas" CT and its manual segmentation are used to learn a two-class sparse dictionary for hemorrhage and normal tissue. Next, for a given "subject" CT, a subject patch is modeled as a sparse convex combination of a few atlas patches from the dictionary. The same convex combination is applied to the atlas segmentation patches to generate a membership for the hemorrhages at each voxel. Hemorrhages are segmented from 25 subjects with various degrees of TBI. Results are compared with segmentations obtained from an expert rater. A median Dice coefficient of 0.85 between automated and manual segmentations is achieved. A linear fit between automated and manual volumes show a slope of 1.0047, indicating a negligible bias in volume estimation.

  11. Second Generation Gold Nanobeacons for Robust K-Edge Imaging with Multi-Energy CT

    PubMed Central

    Schirra, Carsten O.; Senpan, Angana; Roessl, Ewald; Thran, Axel; Stacy, Allen J.; Wu, Lina; Proska, Roland; Pan, Dipanjan

    2012-01-01

    Spectral CT is the newest advancement in CT imaging technology, which enhances traditional CT images with the capability to image and quantify certain elements based on their distinctive K-edge energies. K-edge imaging feature recognizes high accumulations of targeted elements and presents them as colorized voxels against the normal grayscale X-ray background offering promise to overcome the relatively low inherent contrast within soft tissue and distinguish the high attenuation of calcium from contrast enhanced targets. Towards this aim, second generation gold nanobeacons (GNB2), which incorporate at least five times more metal than the previous generation was developed. The particles were synthesized as lipid-encapsulated, vascularly constrained (>120 nm) nanoparticle incorporating tiny gold nanoparticles (2–4 nm) within a polysorbate core. The choice of core material dictated to achieve a higher metal loading. The particles were thoroughly characterized by physicochemical techniques. This study reports one of the earlier examples of spectral CT imaging with gold nanoparticles demonstrating the potential for targeted in vitro and in vivo imaging and eliminates calcium interference with CT. The use of statistical image reconstruction shows high SNR may allow dose reduction and/or faster scan times. PMID:23185109

  12. The impact of spectral filtration on image quality in micro-CT system.

    PubMed

    Ren, Liqiang; Ghani, Muhammad U; Wu, Di; Zheng, Bin; Chen, Yong; Yang, Kai; Wu, Xizeng; Liu, Hong

    2016-01-01

    This paper aims to evaluate the impact of spectral filtration on image quality in a microcomputed tomography (micro-CT) system. A mouse phantom comprising 11 rods for modeling lung, muscle, adipose, and bones was scanned with 17 s and 2 min, respectively. The current (μA) for each scan was adjusted to achieve identical entrance exposure to the phantom, providing a baseline for image quality evaluation. For each region of interest (ROI) within specific composition, CT number variations, noise levels, and contrast-to-noise ratios (CNRs) were evaluated from the reconstructed images. CT number variations and CNRs for bone with high density, muscle, and adipose were compared with theoretical predictions. The results show that the impact of spectral filtration on image quality indicators, such as CNR in a micro-CT system, is significantly associated with tissue characteristics. The findings may provide useful references for optimizing the scanning parameters of general micro-CT systems in future imaging applications. PACS numbers: 87.57.C-, 87.57.Q-, 87.64.kd.

  13. Diagnostic Ability of FDG-PET/CT in the Detection of Malignant Pleural Effusion

    PubMed Central

    Nakajima, Reiko; Abe, Koichiro; Sakai, Shuji

    2015-01-01

    Abstract We investigated the role of F-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for the differential diagnosis of malignant and benign pleural effusion. We studied 36 consecutive patients with histologically proven cancer (excluding malignant mesothelioma) who underwent FDG-PET/CT for suspected malignant pleural effusion. Fourteen patients had cytologically proven malignant pleural effusion and the other 22 patients had either negative cytology or clinical follow-up, which confirmed the benign etiology. We examined the maximum standardized uptake values (SUVmax) of pleural effusion and the target-to-normal tissue ratio (TNR), calculated as the ratio of the pleural effusion SUVmax to the SUVmean of the normal tissues (liver, spleen, 12th thoracic vertebrae [Th12], thoracic aorta, and spinalis muscle). We also examined the size and density (in Hounsfield units) of the pleural effusion and pleural abnormalities on CT images. TNR (Th12) and increased pleural FDG uptake compared to background blood pool were significantly more frequent in cases with malignant pleural effusion (P < 0.05 for both). The cutoff TNR (Th12) value of >0.95 was the most accurate; the sensitivity, specificity, and accuracy for this value were 93%, 68%, and 75%, respectively. FDG-PET/CT can be a useful method for the differential diagnosis of malignant and benign pleural effusion. PMID:26200610

  14. NOTE: X-ray CT high-density artefact suppression in cryosurgery

    NASA Astrophysics Data System (ADS)

    Wei, Jikun; Sandison, George A.; Chen, Laigao; Liang, Yun; Xu, Lisa X.

    2002-12-01

    Advantages of x-ray CT for imaging guidance of cryosurgery include 3D visualization of frozen and unfrozen tissue and calibration of temperature in the tissue water-ice interface (0-10 °C) to Hounsfield units. However, use of x-ray CT images and their thermal calibration can be compromised by the cryoprobes generating high-density streak artefacts. A new subtraction technique for artefact suppression is proposed and tested in prostate cryosurgery simulations. By subtracting the measured CT x-ray projection profile without cryoprobes from the profile with cryoprobes plus iceballs, one obtains the combined profile of the cryoprobes and a low value background. Polynomial interpolation to obtain the background profile allows its addition to the original profile without probes. The result may then be fed to a conventional filtered back-projection routine to reconstruct the probe-free image. Finally the cryoprobe pixels in the originally constructed image with probes and iceballs are added back to the probe-free image to get the final artefact-suppressed image. The major advantage of this subtraction technique is that it can successfully suppress the high-density artefacts in bone-abundant body regions such as the pelvis. X-ray CT images of cryoprobe arrays in a homogeneous gelatin phantom and the pelvic region of an anthropomorphic Rando phantom containing a human skeleton were generated. After suppression, cryoprobe metal artefact streaks are reduced and visualization of the positions and dimensions of the cryoprobes are well preserved.

  15. Model-based pancreas segmentation in portal venous phase contrast-enhanced CT images.

    PubMed

    Hammon, Matthias; Cavallaro, Alexander; Erdt, Marius; Dankerl, Peter; Kirschner, Matthias; Drechsler, Klaus; Wesarg, Stefan; Uder, Michael; Janka, Rolf

    2013-12-01

    This study aims to automatically detect and segment the pancreas in portal venous phase contrast-enhanced computed tomography (CT) images. The institutional review board of the University of Erlangen-Nuremberg approved this study and waived the need for informed consent. Discriminative learning is used to build a pancreas tissue classifier incorporating spatial relationships between the pancreas and surrounding organs and vessels. Furthermore, discrete cosine and wavelet transforms are used to build texture features to describe local tissue appearance. Classification is used to guide a constrained statistical shape model to fit the data. The algorithm to detect and segment the pancreas was evaluated on 40 consecutive CT data that were acquired in the portal venous contrast agent phase. Manual segmentation of the pancreas was carried out by experienced radiologists and served as reference standard. Threefold cross validation was performed. The algorithm-based detection and segmentation yielded an average surface distance of 1.7 mm and an average overlap of 61.2 % compared with the reference standard. The overall runtime of the system was 20.4 min. The presented novel approach enables automatic pancreas segmentation in portal venous phase contrast-enhanced CT images which are included in almost every clinical routine abdominal CT examination. Reliable pancreatic segmentation is crucial for computer-aided detection systems and an organ-specific decision support.

  16. A Novel Mouse Segmentation Method Based on Dynamic Contrast Enhanced Micro-CT Images

    PubMed Central

    Yan, Dongmei; Zhang, Zhihong; Luo, Qingming; Yang, Xiaoquan

    2017-01-01

    With the development of hybrid imaging scanners, micro-CT is widely used in locating abnormalities, studying drug metabolism, and providing structural priors to aid image reconstruction in functional imaging. Due to the low contrast of soft tissues, segmentation of soft tissue organs from mouse micro-CT images is a challenging problem. In this paper, we propose a mouse segmentation scheme based on dynamic contrast enhanced micro-CT images. With a homemade fast scanning micro-CT scanner, dynamic contrast enhanced images were acquired before and after injection of non-ionic iodinated contrast agents (iohexol). Then the feature vector of each voxel was extracted from the signal intensities at different time points. Based on these features, the heart, liver, spleen, lung, and kidney could be classified into different categories and extracted from separate categories by morphological processing. The bone structure was segmented using a thresholding method. Our method was validated on seven BALB/c mice using two different classifiers: a support vector machine classifier with a radial basis function kernel and a random forest classifier. The results were compared to manual segmentation, and the performance was assessed using the Dice similarity coefficient, false positive ratio, and false negative ratio. The results showed high accuracy with the Dice similarity coefficient ranging from 0.709 ± 0.078 for the spleen to 0.929 ± 0.006 for the kidney. PMID:28060917

  17. SU-E-J-219: A Dixon Based Pseudo-CT Generation Method for MR-Only Radiotherapy Treatment Planning of the Pelvis and Head and Neck

    SciTech Connect

    Maspero, M.; Meijer, G.J.; Lagendijk, J.J.W.; Berg, C.A.T. van den; Seevinck, P.R.; Viergever, M.A.

    2015-06-15

    Purpose: To develop an image processing method for MRI-based generation of electron density maps, known as pseudo-CT (pCT), without usage of model- or atlas-based segmentation, and to evaluate the method in the pelvic and head-neck region against CT. Methods: CT and MRI scans were obtained from the pelvic region of four patients in supine position using a flat table top only for CT. Stratified CT maps were generated by classifying each voxel based on HU ranges into one of four classes: air, adipose tissue, soft tissue or bone.A hierarchical region-selective algorithm, based on automatic thresholding and clustering, was used to classify tissues from MR Dixon reconstructed fat, In-Phase (IP) and Opposed-Phase (OP) images. First, a body mask was obtained by thresholding the IP image. Subsequently, an automatic threshold on the Dixon fat image differentiated soft and adipose tissue. K-means clustering on IP and OP images resulted in a mask that, via a connected neighborhood analysis, allowing the user to select the components corresponding to bone structures.The pCT was estimated through assignment of bulk HU to the tissue classes. Bone-only Digital Reconstructed Radiographs (DRR) were generated as well. The pCT images were rigidly registered to the stratified CT to allow a volumetric and voxelwise comparison. Moreover, pCTs were also calculated within the head-neck region in two volunteers using the same pipeline. Results: The volumetric comparison resulted in differences <1% for each tissue class. A voxelwise comparison showed a good classification, ranging from 64% to 98%. The primary misclassified classes were adipose/soft tissue and bone/soft tissue. As the patients have been imaged on different table tops, part of the misclassification error can be explained by misregistration. Conclusion: The proposed approach does not rely on an anatomy model providing the flexibility to successfully generate the pCT in two different body sites. This research is founded by Zon

  18. Micro-CT in the Assessment of Pediatric Renal Osteodystrophy by Bone Histomorphometry

    PubMed Central

    Pereira, Renata C.; Bischoff, David S.; Yamaguchi, Dean; Salusky, Isidro B.

    2016-01-01

    Background and objectives Computed tomography (CT) measurements can distinguish between cortical and trabecular bone density in vivo. High-resolution CTs assess both bone volume and density in the same compartment, thus potentially yielding information regarding bone mineralization as well. The relationship between bone histomorphometric parameters of skeletal mineralization and bone density from microcomputed tomography (μCT) measurements of bone cores from patients on dialysis has not been assessed. Design, setting, participants, & measurements Bone cores from 68 patients with ESRD (age =13.9±0.5 years old; 50% men) and 14 controls (age =15.3±3.8 years old; 50% men) obtained as part of research protocols between 1983 and 2006 were analyzed by bone histomorphometry and μCT. Results Bone histomorphometric diagnoses in the patients were normal to high bone turnover in 76%, adynamic bone in 13%, and osteomalacia in 11%. Bone formation rate did not correlate with any μCT determinations. Bone volume measurements were highly correlated between bone histomorphometry and μCT (bone volume/tissue volume between the two techniques: r=0.70; P<0.001, trabecular thickness and trabecular separation: r=0.71; P<0.001, and r=0.56; P<0.001, respectively). Osteoid accumulation as determined by bone histomorphometry correlated inversely with bone mineral density as assessed by μCT (osteoid thickness: r=−0.32; P=0.01 and osteoid volume: r=−0.28; P=0.05). By multivariable analysis, the combination of bone mineral density and bone volume (as assessed by μCT) along with parathyroid hormone and calcium levels accounted for 38% of the variability in osteoid volume (by histomorphometry). Conclusions Measures of bone volume can be accurately assessed with μCT. Bone mineral density is lower in patients with excessive osteoid accumulation and higher in patients with adynamic, well mineralized bone. Thus, bone mineralization may be accurately assessed by μCT of bone biopsy cores

  19. Comparison of thoracic radiographs and single breath-hold helical CT for detection of pulmonary nodules in dogs with metastatic neoplasia.

    PubMed

    Nemanic, Sarah; London, Cheryl A; Wisner, Erik R

    2006-01-01

    Imaging studies in people indicate that x-ray computed tomography (CT) is a more sensitive technique than thoracic radiography for the detection of pulmonary metastasic neoplasia. Systematic studies comparing CT and thoracic radiographic techniques in veterinary patients have not been performed. The present retrospective study was designed to directly compare the efficacy of these 2 techniques in detecting pulmonary nodules in dogs. Eighteen dogs with histologically confirmed pulmonary metastatic neoplasia had contemporaneous thoracic radiographs and pulmonary CT scans compared. Quantitative analyses included estimation of pulmonary nodule size, number, and lobar distribution on thoracic radiographs and CT images. Only 9% of CT-detected pulmonary nodules were identified on thoracic radiographs (P < .003). The lower size threshold was approximately 1 mm to detect pulmonary nodules on CT images and 7-9 mm to reliably detect nodules on radiographs (P < .0001). Additionally, pulmonary nodules were detected in a significantly greater number of lung lobes using CT as compared with thoracic radiographs (P < .0001). These data indicate that CT is significantly more sensitive than thoracic radiography for detecting soft-tissue nodules in dogs. As such, thoracic CT should be considered in any patient with neoplasia that has potential for pulmonary metastasis to more reliably stage the disease, particularly when accurate characterization of the extent and distribution of pulmonary metastatic disease affects therapeutic planning.

  20. Radiation exposure in whole body CT screening.

    PubMed

    Suresh, Pamidighantam; Ratnam, S V; Rao, K V J

    2011-04-01

    Using a technology that "takes a look" at people's insides and promises early warnings of cancer, cardiac disease, and other abnormalities, clinics and medical imaging facilities nationwide are touting a new service for health conscious people: "Whole body CT screening" this typically involves scanning the body from the chin to below the hips with a form of x-ray imaging that produces cross-sectional images. In USA direct-to-consumer marketing of whole body CT is occurring today in many metropolitan areas. Free standing CT screening centres are being sited in shopping malls and other high density public areas, and these centres are being advertised in the electronic and print media. In this context the present article discussed the pros and cons of having such centres in India with the advent of multislice CT leading to fast scan times.

  1. CT appearance of thickened nerves in neurofibromatosis

    SciTech Connect

    Daneman, A.; Mancer, K.; Sonley, M.

    1983-11-01

    In neutrofibromatosis (von Recklinghausen disease), peripheral nerves may develop enlarged diameters or focal fusiform enlargement due to neurofibromatous involvement. Their appearance on computed tomography (CT) forms the basis of this report.

  2. Use of CT in stapedial otosclerosis

    SciTech Connect

    Mafee, M.F.; Henrikson, G.C.; Deitch, R.L.; Norouzi, P.; Kumar, A.; Kriz, R.; Valvassori, G.E.

    1985-09-01

    Otosclerosis (otospongiosis) is a primary focal disease of the labyrinthine capsule. The stapes footplate is fixed when the spongiotic focus expands and invades the oval window. Persons with stapedial otosclerosis experience a progressive conductive hearing loss. In many cases, cochlear degeneration is observed, in which a mixed hearing loss occurs. Using computed tomography (CT), the authors studied the ears of 45 selected patients with conductive or mixed hearing loss. CT proved valuable in determining otosclerotic changes of the oval window and otic capsule. Spongiotic changes of the otic capsule are better appreciated by CT than complex motion tomography. The usefulness of CT in diagnosing other causes of conductive or mixed hearing loss is also described.

  3. CT in the diagnosis of enterovesical fistulae

    SciTech Connect

    Goldman, S.M.; Fishman, E.K.; Gatewood, O.M.B.; Jones, B.; Siegelman, S.S.

    1985-06-01

    Enterovesical fistulae are difficult to demonstrate by conventional radiographic methods. Computed tomography (CT), a sensitive, noninvasive method of documenting the presence of such fistulae, is unique in its ability to outline the extravesical component of the primary disease process. Twenty enterovesical fistulae identified by CT were caused by diverticulitis (nine), carcinoma of the rectosigmoid (two), Crohn disease (three), gynecologic tumors (two), bladder cancer (one), cecal carcinoma (one), prostatic neoplasia (one), and appendiceal abscess (one). The CT findings included intravesical air (90%), passage of orally or rectally administered contrast medium into the bladder (20%), focal bladder-wall thickening (90%), thickening of adjacent bowel wall (85%), and an extraluminal mass that often contained air (75%). CT proved to be an important new method in the diagnosis of enterovesical fistulae.

  4. MR and CT appearance of cardiac hemangioma

    SciTech Connect

    Kemp, J.L.; Kessler, R.M.; Raizada, V.; Williamson, M.R.

    1996-05-01

    We present a case of cardiac hemangioma in a symptomatic patient. MR and CT each have specific characteristics that should make one consider including or excluding this in the differential diagnosis of a cardiac tumor. 7 refs., 3 figs.

  5. Measuring CT scanner variability of radiomics features

    PubMed Central

    Mackin, Dennis; Fave, Xenia; Zhang, Lifei; Fried, David; Yang, Jinzhong; Taylor, Brian; Rodriguez-Rivera, Edgardo; Dodge, Cristina; Jones, A. Kyle; Court, Laurence

    2015-01-01

    Objectives The purpose of this study was to determine the significance of inter-scanner variability in CT image radiomics studies. Materials and Methods We compared the radiomics features calculated for non-small cell lung cancer (NSCLC) tumors from 20 patients with those calculated for 17 scans of a specially designed radiomics phantom. The phantom comprised 10 cartridges, each filled with different materials to produce a wide range of radiomics feature values. The scans were acquired using General Electric, Philips, Siemens, and Toshiba scanners from four medical centers using their routine thoracic imaging protocol. The radiomics feature studied included the mean and standard deviations of the CT numbers as well as textures derived from the neighborhood gray-tone difference matrix. To quantify the significance of the inter-scanner variability, we introduced the metric feature noise. To look for patterns in the scans, we performed hierarchical clustering for each cartridge. Results The mean CT numbers for the 17 CT scans of the phantom cartridges spanned from -864 to 652 Hounsfield units compared with a span of -186 to 35 Hounsfield units for the CT scans of the NSCLC tumors, showing that the phantom’s dynamic range includes that of the tumors. The inter-scanner variability of the feature values depended on both the cartridge material and the feature, and the variability was large relative to the inter-patient variability in the NSCLC tumors for some features. The feature inter-scanner noise was greatest for busyness and least for texture strength. Hierarchical clustering produced different clusters of the phantom scans for each cartridge, although there was some consistent clustering by scanner manufacturer. Conclusions The variability in the values of radiomics features calculated on CT images from different CT scanners can be comparable to the variability in these features found in CT images of NSCLC tumors. These inter-scanner differences should be

  6. CT of trauma to the abnormal kidney

    SciTech Connect

    Rhyner, P.; Federle, M.P.; Jeffrey, R.B.

    1984-04-01

    Traumatic injuries to already abnormal kidneys are difficult to assess by excretory urography and clinical evaluation. Bleeding and urinary extravasation may accompany minor trauma; conversely, underlying tumors, perirenal hemorrhage, and extravasation may be missed on urography. Computed tomography (CT) was performed in eight cases including three neoplasms, one adult polycystic disease, one simple renal cyst, two hydronephrotic kidneys, and one horseshoe kidney. CT provided specific and clinically useful information in each case that was not apparent on excretory urography.

  7. Bronchogenic cysts with high CT numbers

    SciTech Connect

    Mendelson, D.S.; Rose, J.S.; Efremidis, S.C.; Kirschner, P.A.; Cohen, B.A.

    1983-03-01

    Four patients with mediastinal masses are described. CT examinations demonstrated masses of high attenuation, and solid masses were suspected. At thoracotomy each patient had a cystic mass containing a brownish, turbid, mucoid material. The pathologic diagnosis in each case was a bronchogenic cyst. The possibility of such a cyst should not be excluded because of a high CT number, which reflects the turbid contents of the cyst.

  8. ADAPTIVE SMALL-ANIMAL SPECT/CT

    PubMed Central

    Furenlid, L.R.; Moore, J.W.; Freed, M.; Kupinski, M.A.; Clarkson, E.; Liu, Z.; Wilson, D.W.; Woolfenden, J.M.; Barrett, H.H.

    2015-01-01

    We are exploring the concept of adaptive multimodality imaging, a form of non-linear optimization where the imaging configuration is automatically adjusted in response to the object. Preliminary studies suggest that substantial improvement in objective, task-based measures of image quality can result. We describe here our work to add motorized adjustment capabilities and a matching CT to our existing FastSPECT II system to form an adaptive small-animal SPECT/CT. PMID:26617457

  9. Joint regularization for spectro-temporal CT reconstruction

    NASA Astrophysics Data System (ADS)

    Clark, D. P.; Badea, C. T.

    2016-03-01

    X-ray CT is widely used, both clinically and preclinically, for fast, high-resolution, anatomic imaging; however, compelling opportunities exist to expand its use in functional imaging applications. For instance, spectral information combined with nanoparticle contrast agents enables quantification of tissue perfusion levels, while temporal information details cardiac and respiratory dynamics. In previous work, we proposed and demonstrated a projection acquisition and reconstruction strategy for 5D CT (3D + dual-energy + time) which recovered spectral and temporal information without substantially increasing radiation dose or sampling time relative to anatomic imaging protocols. The approach relied on the approximate separability of the temporal and spectral reconstruction sub-problems, which enabled substantial projection undersampling and effective regularization. Here, we extend this previous work to more general, nonseparable 5D CT reconstruction cases (3D + muti-energy + time) with applicability to K-edge imaging of exogenous contrast agents. We apply the newly proposed algorithm in phantom simulations using a realistic system and noise model for a photon counting x-ray detector with six energy thresholds. The MOBY mouse phantom used contains realistic concentrations of iodine, gold, and calcium in water. Relative to weighted least-squares reconstruction, the proposed 5D reconstruction algorithm improved reconstruction and material decomposition accuracy by 3-18 times. Furthermore, by exploiting joint, low rank image structure between time points and energies, ~80 HU of contrast associated with the Kedge of gold and ~35 HU of contrast associated with the blood pool and myocardium were recovered from more than 400 HU of noise.

  10. Application of the optically stimulated luminescence (OSL) technique for mouse dosimetry in micro-CT imaging

    SciTech Connect

    Vrigneaud, Jean-Marc; Courteau, Alan; Oudot, Alexandra; Collin, Bertrand; Ranouil, Julien; Morgand, Loïc; Raguin, Olivier; Walker, Paul; Brunotte, François

    2013-12-15

    Purpose: Micro-CT is considered to be a powerful tool to investigate various models of disease on anesthetized animals. In longitudinal studies, the radiation dose delivered by the micro-CT to the same animal is a major concern as it could potentially induce spurious effects in experimental results. Optically stimulated luminescence dosimeters (OSLDs) are a relatively new kind of detector used in radiation dosimetry for medical applications. The aim of this work was to assess the dose delivered by the CT component of a micro-SPECT (single-photon emission computed tomography)/CT camera during a typical whole-body mouse study, using commercially available OSLDs based on Al{sub 2}O{sub 3}:C crystals.Methods: CTDI (computed tomography dose index) was measured in micro-CT with a properly calibrated pencil ionization chamber using a rat-like phantom (60 mm in diameter) and a mouse-like phantom (30 mm in diameter). OSLDs were checked for reproducibility and linearity in the range of doses delivered by the micro-CT. Dose measurements obtained with OSLDs were compared to those of the ionization chamber to correct for the radiation quality dependence of OSLDs in the low-kV range. Doses to tissue were then investigated in phantoms and cadavers. A 30 mm diameter phantom, specifically designed to insert OSLDs, was used to assess radiation dose over a typical whole-body mouse imaging study. Eighteen healthy female BALB/c mice weighing 27.1 ± 0.8 g (1 SD) were euthanized for small animal measurements. OLSDs were placed externally or implanted internally in nine different locations by an experienced animal technician. Five commonly used micro-CT protocols were investigated.Results: CTDI measurements were between 78.0 ± 2.1 and 110.7 ± 3.0 mGy for the rat-like phantom and between 169.3 ± 4.6 and 203.6 ± 5.5 mGy for the mouse-like phantom. On average, the displayed CTDI at the operator console was underestimated by 1.19 for the rat-like phantom and 2.36 for the mouse

  11. Correlation of X-ray computed tomography with quantitative nuclear magnetic resonance methods for pre-clinical measurement of adipose and lean tissues in living mice.

    PubMed

    Metzinger, Matthew N; Miramontes, Bernadette; Zhou, Peng; Liu, Yueying; Chapman, Sarah; Sun, Lucy; Sasser, Todd A; Duffield, Giles E; Stack, M Sharon; Leevy, W Matthew

    2014-10-08

    Numerous obesity studies have coupled murine models with non-invasive methods to quantify body composition in longitudinal experiments, including X-ray computed tomography (CT) or quantitative nuclear magnetic resonance (QMR). Both microCT and QMR have been separately validated with invasive techniques of adipose tissue quantification, like post-mortem fat extraction and measurement. Here we report a head-to-head study of both protocols using oil phantoms and mouse populations to determine the parameters that best align CT data with that from QMR. First, an in vitro analysis of oil/water mixtures was used to calibrate and assess the overall accuracy of microCT vs. QMR data. Next, experiments were conducted with two cohorts of living mice (either homogenous or heterogeneous by sex, age and genetic backgrounds) to assess the microCT imaging technique for adipose tissue segmentation and quantification relative to QMR. Adipose mass values were obtained from microCT data with three different resolutions, after which the data were analyzed with different filter and segmentation settings. Strong linearity was noted between the adipose mass values obtained with microCT and QMR, with optimal parameters and scan conditions reported herein. Lean tissue (muscle, internal organs) was also segmented and quantified using the microCT method relative to the analogous QMR values. Overall, the rigorous calibration and validation of the microCT method for murine body composition, relative to QMR, ensures its validity for segmentation, quantification and visualization of both adipose and lean tissues.

  12. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a good'' surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  13. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a ``good`` surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  14. CT evaluation of the colon: inflammatory disease.

    PubMed

    Horton, K M; Corl, F M; Fishman, E K

    2000-01-01

    Computed tomography (CT) is valuable for detection and characterization of many inflammatory conditions of the colon. At CT, a dilated, thickened appendix is suggestive of appendicitis. A 1-4-cm, oval, fatty pericolic lesion with surrounding mesenteric inflammation is diagnostic of epiploic appendagitis. The key to distinguishing diverticulitis from other inflammatory conditions of the colon is the presence of diverticula in the involved segment. In typhlitis, CT demonstrates cecal distention and circumferential thickening of the cecal wall, which may have low attenuation secondary to edema. In radiation colitis, the clinical history is the key to suggesting the diagnosis because the CT findings can be nonspecific. The location of the involved segment and the extent and appearance of wall thickening may help distinguish Crohn disease and ulcerative colitis. In ischemic colitis, CT typically demonstrates circumferential, symmetric wall thickening with fold enlargement. CT findings of graft-versus-host disease include small bowel and colonic wall thickening, which may result in luminal narrowing and separation of bowel loops. In infectious colitis, the site and thickness of colon affected may suggest a specific organism. The amount of wall thickening in pseudomembranous colitis is typically greater than in any other inflammatory disease of the colon except Crohn disease.

  15. Negative appendectomy rate: influence of CT scans.

    PubMed

    McGory, Marcia L; Zingmond, David S; Nanayakkara, Darshani; Maggard, Melinda A; Ko, Clifford Y

    2005-10-01

    Negative appendectomy rate varies significantly depending on patient age and sex. However, the impact of computed tomography (CT) scans on the diagnosis of appendicitis is unknown. The goal of this study was to examine the negative appendectomy rate using a statewide database and analyze the association of receipt of CT scan. Using the California Inpatient File, all patients undergoing appendectomy in 1999-2000 were identified (n = 75,452). Demographic and clinical data were analyzed, including procedure approach (open vs laparoscopic) and appendicitis type (negative, simple, abscess, peritonitis). Patients with CT scans performed were identified to compare the negative appendectomy rate. For the entire cohort, appendicitis type was 59 per cent simple, 10 per cent with abscess, 18.7 per cent with peritonitis, and 9.3 per cent negative. Males had a lower rate of negative appendicitis than females (6.0% vs 13.4%, P < 0.0001). The use of CT scans was associated with an overall lower negative appendectomy rate for females, especially in the < 5 years and > 45 years age categories. Use of CT scans in males does not appear to be efficacious, as the negative appendectomy rates were similar across all age categories. In conclusion, use of CT was associated with lower rate of negative appendectomy, depending on patient age and sex.

  16. Validating and improving CT ventilation imaging by correlating with ventilation 4D-PET/CT using {sup 68}Ga-labeled nanoparticles

    SciTech Connect

    Kipritidis, John Keall, Paul J.; Siva, Shankar; Hofman, Michael S.; Callahan, Jason; Hicks, Rodney J.

    2014-01-15

    Purpose: CT ventilation imaging is a novel functional lung imaging modality based on deformable image registration. The authors present the first validation study of CT ventilation using positron emission tomography with{sup 68}Ga-labeled nanoparticles (PET-Galligas). The authors quantify this agreement for different CT ventilation metrics and PET reconstruction parameters. Methods: PET-Galligas ventilation scans were acquired for 12 lung cancer patients using a four-dimensional (4D) PET/CT scanner. CT ventilation images were then produced by applying B-spline deformable image registration between the respiratory correlated phases of the 4D-CT. The authors test four ventilation metrics, two existing and two modified. The two existing metrics model mechanical ventilation (alveolar air-flow) based on Hounsfield unit (HU) change (V{sub HU}) or Jacobian determinant of deformation (V{sub Jac}). The two modified metrics incorporate a voxel-wise tissue-density scaling (ρV{sub HU} and ρV{sub Jac}) and were hypothesized to better model the physiological ventilation. In order to assess the impact of PET image quality, comparisons were performed using both standard and respiratory-gated PET images with the former exhibiting better signal. Different median filtering kernels (σ{sub m} = 0 or 3 mm) were also applied to all images. As in previous studies, similarity metrics included the Spearman correlation coefficient r within the segmented lung volumes, and Dice coefficient d{sub 20} for the (0 − 20)th functional percentile volumes. Results: The best agreement between CT and PET ventilation was obtained comparing standard PET images to the density-scaled HU metric (ρV{sub HU}) with σ{sub m} = 3 mm. This leads to correlation values in the ranges 0.22 ⩽ r ⩽ 0.76 and 0.38 ⩽ d{sub 20} ⩽ 0.68, with r{sup ¯}=0.42±0.16 and d{sup ¯}{sub 20}=0.52±0.09 averaged over the 12 patients. Compared to Jacobian-based metrics, HU-based metrics lead to statistically significant

  17. Liver segmentation for CT images using GVF snake

    SciTech Connect

    Liu Fan; Zhao Binsheng; Kijewski, Peter K.; Wang Liang; Schwartz, Lawrence H.

    2005-12-15

    Accurate liver segmentation on computed tomography (CT) images is a challenging task especially at sites where surrounding tissues (e.g., stomach, kidney) have densities similar to that of the liver and lesions reside at the liver edges. We have developed a method for semiautomatic delineation of the liver contours on contrast-enhanced CT images. The method utilizes a snake algorithm with a gradient vector flow (GVF) field as its external force. To improve the performance of the GVF snake in the segmentation of the liver contour, an edge map was obtained with a Canny edge detector, followed by modifications using a liver template and a concavity removal algorithm. With the modified edge map, for which unwanted edges inside the liver were eliminated, the GVF field was computed and an initial liver contour was formed. The snake algorithm was then applied to obtain the actual liver contour. This algorithm was extended to segment the liver volume in a slice-by-slice fashion, where the result of the preceding slice constrained the segmentation of the adjacent slice. 551 two-dimensional liver images from 20 volumetric images with colorectal metastases spreading throughout the livers were delineated using this method, and also manually by a radiologist for evaluation. The difference ratio, which is defined as the percentage ratio of mismatching volume between the computer and the radiologist's results, ranged from 2.9% to 7.6% with a median value of 5.3%.

  18. Spectral CT data acquisition with Medipix3.1

    NASA Astrophysics Data System (ADS)

    Walsh, M. F.; Nik, S. J.; Procz, S.; Pichotka, M.; Bell, S. T.; Bateman, C. J.; Doesburg, R. M. N.; De Ruiter, N.; Chernoglazov, A. I.; Panta, R. K.; Butler, A. P. H.; Butler, P. H.

    2013-10-01

    This paper describes the acquisition of spectral CT images using the Medipix3.1 in spectroscopic mode, in which the chip combines 2 × 2 pixel clusters to increase the number of energy thresholds and counters from 2 to 8. During preliminary measurements, it was observed that the temperature, DAC and equalisation stability of the Medipix3.1 outperformed the Medipix3.0, while maintaining similar imaging quality. In this paper, the Medipix3.1 chips were assembled in a quad (2 × 2) layout, with the four ASICs bump-bonded to a silicon semiconductor doped as an np-junction diode. To demonstrate the biological imaging quality that is possible with the Medipix3.1, an image of a mouse injected with gold nano-particle contrast agent was obtained. CT acquisition in spectroscopic mode was enabled and examined by imaging a customised phantom containing multiple contrast agents and biological materials. These acquisitions showed a limitation of imaging performance depending on the counter used. Despite this, identification of multiple materials in the phantom was demonstrated using an in-house material decomposition algorithm. Furthermore, gold nano-particles were separated from biological tissues and bones within the mouse by means of image rendering.

  19. A material decomposition method for dual energy micro-CT

    NASA Astrophysics Data System (ADS)

    Johnston, S. M.; Johnson, G. A.; Badea, C. T.

    2009-02-01

    The attenuation of x-rays in matter is dependent on the energy of the x-rays and the atomic composition of the matter. Attenuation measurements at multiple x-ray energies can be used to improve the identification of materials. We present a method to estimate the fractional composition of three materials in an object from x-ray CT measurements at two different energies. The energies can be collected from measurements from a single source-detector system at two points in time, or from a dual source-detector system at one point in time. This method sets up a linear system of equations from the measurements and finds the solution through a geometric construction of the inverse matrix equation. This method enables the estimation of the blood fraction within a region of living tissue in which blood containing an iodinated contrast agent is mixed with two other materials. We verified this method using x-ray CT simulations implemented in MATLAB, investigated the parameters needed to optimize the estimation, and then applied the method to a mouse model of lung cancer. A direct application of this method is the estimation of blood fraction in lung tumors in preclinical studies. This work was performed at the Duke Center for In Vivo Microscopy, an NCRR/NCI National Resource (P41 RR005959/U24 CA092656), and also supported by NCI R21 CA124584.

  20. T1-weighted MRI as a substitute to CT for refocusing planning in MR-guided focused ultrasound.

    PubMed

    Wintermark, Max; Tustison, Nicholas J; Elias, William J; Patrie, James T; Xin, Wenjun; Demartini, Nicholas; Eames, Matt; Sumer, Suna; Lau, Benison; Cupino, Alan; Snell, John; Hananel, Arik; Kassell, Neal; Aubry, Jean-Francois

    2014-07-07

    Precise focusing is essential for transcranial MRI-guided focused ultrasound (TcMRgFUS) to minimize collateral damage to non-diseased tissues and to achieve temperatures capable of inducing coagulative necrosis at acceptable power deposition levels. CT is usually used for this refocusing but requires a separate study (CT) ahead of the TcMRgFUS procedure. The goal of this study was to determine whether MRI using an appropriate sequence would be a viable alternative to CT for planning ultrasound refocusing in TcMRgFUS. We tested three MRI pulse sequences (3D T1 weighted 3D volume interpolated breath hold examination (VIBE), proton density weighted 3D sampling perfection with applications optimized contrasts using different flip angle evolution and 3D true fast imaging with steady state precision T2-weighted imaging) on patients who have already had a CT scan performed. We made detailed measurements of the calvarial structure based on the MRI data and compared those so-called 'virtual CT' to detailed measurements of the calvarial structure based on the CT data, used as a reference standard. We then loaded both standard and virtual CT in a TcMRgFUS device and compared the calculated phase correction values, as well as the temperature elevation in a phantom. A series of Bland-Altman measurement agreement analyses showed T1 3D VIBE as the optimal MRI sequence, with respect to minimizing the measurement discrepancy between the MRI derived total skull thickness measurement and the CT derived total skull thickness measurement (mean measurement discrepancy: 0.025; 95% CL (-0.22-0.27); p = 0.825). The T1-weighted sequence was also optimal in estimating skull CT density and skull layer thickness. The mean difference between the phase shifts calculated with the standard CT and the virtual CT reconstructed from the T1 dataset was 0.08 ± 1.2 rad on patients and 0.1 ± 0.9 rad on phantom. Compared to the real CT, the MR-based correction showed a 1 °C drop on the maximum

  1. Necrotizing soft tissue infection

    MedlinePlus

    Necrotizing fasciitis; Fasciitis - necrotizing; Flesh-eating bacteria; Soft tissue gangrene; Gangrene - soft tissue ... Many different types of bacteria can cause this infection. A very severe and usually deadly form of necrotizing soft tissue infection is due to the ...

  2. Undifferentiated Connective Tissue Disease

    MedlinePlus

    ... Home Conditions Undifferentiated Connective Tissue Disease (UCTD) Undifferentiated Connective Tissue Disease (UCTD) Make an Appointment Find a Doctor ... L. Goldstein, MD, MMSc (February 01, 2016) Undifferentiated connective tissue disease (UCTD) is a systemic autoimmune disease. This ...

  3. Impact of CT attenuation correction method on quantitative respiratory-correlated (4D) PET/CT imaging

    SciTech Connect

    Nyflot, Matthew J.; Lee, Tzu-Cheng; Alessio, Adam M.; Kinahan, Paul E.; Wollenweber, Scott D.; Stearns, Charles W.; Bowen, Stephen R.

    2015-01-15

    Purpose: Respiratory-correlated positron emission tomography (PET/CT) 4D PET/CT is used to mitigate errors from respiratory motion; however, the optimal CT attenuation correction (CTAC) method for 4D PET/CT is unknown. The authors performed a phantom study to evaluate the quantitative performance of CTAC methods for 4D PET/CT in the ground truth setting. Methods: A programmable respiratory motion phantom with a custom movable insert designed to emulate a lung lesion and lung tissue was used for this study. The insert was driven by one of five waveforms: two sinusoidal waveforms or three patient-specific respiratory waveforms. 3DPET and 4DPET images of the phantom under motion were acquired and reconstructed with six CTAC methods: helical breath-hold (3DHEL), helical free-breathing (3DMOT), 4D phase-averaged (4DAVG), 4D maximum intensity projection (4DMIP), 4D phase-matched (4DMATCH), and 4D end-exhale (4DEXH) CTAC. Recovery of SUV{sub max}, SUV{sub mean}, SUV{sub peak}, and segmented tumor volume was evaluated as RC{sub max}, RC{sub mean}, RC{sub peak}, and RC{sub vol}, representing percent difference relative to the static ground truth case. Paired Wilcoxon tests and Kruskal–Wallis ANOVA were used to test for significant differences. Results: For 4DPET imaging, the maximum intensity projection CTAC produced significantly more accurate recovery coefficients than all other CTAC methods (p < 0.0001 over all metrics). Over all motion waveforms, ratios of 4DMIP CTAC recovery were 0.2 ± 5.4, −1.8 ± 6.5, −3.2 ± 5.0, and 3.0 ± 5.9 for RC{sub max}, RC{sub peak}, RC{sub mean}, and RC{sub vol}. In comparison, recovery coefficients for phase-matched CTAC were −8.4 ± 5.3, −10.5 ± 6.2, −7.6 ± 5.0, and −13.0 ± 7.7 for RC{sub max}, RC{sub peak}, RC{sub mean}, and RC{sub vol}. When testing differences between phases over all CTAC method