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Sample records for carcinoma ct scan

  1. 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 ...

  2. 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. ...

  3. Pelvic CT scan

    MedlinePlus

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... creates detailed pictures of the body, including the pelvis and areas near the pelvis. The test may ...

  4. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... on film. Three-dimensional (3D) models of the leg can be created by adding the slices together. ...

  5. CT-scan prediction of thyroid cartilage invasion for early laryngeal squamous cell carcinoma.

    PubMed

    Hartl, Dana M; Landry, Guillaume; Bidault, François; Hans, Stéphane; Julieron, Morbize; Mamelle, Gérard; Janot, François; Brasnu, Daniel F

    2013-01-01

    Treatment choice for laryngeal cancer may be influenced by the diagnosis of thyroid cartilage invasion on preoperative computed tomography (CT). Our objective was to determine the predictive value of CT for thyroid cartilage invasion in early- to mid-stage laryngeal cancer. Retrospective study (1992-2008) of laryngeal squamous cell carcinoma treated with open partial laryngectomy and resection of at least part of the thyroid cartilage. Previous laser surgery, radiation therapy, chemotherapy and second primaries were excluded. CT prediction of thyroid cartilage invasion was determined by specialized radiologists. Tumor characteristics and pathologic thyroid cartilage invasion were compared to the radiologic assessment. 236 patients were treated by vertical (20 %), supracricoid (67 %) or supraglottic partial laryngectomy (13 %) for tumors staged cT1 (26 %), cT2 (55 %), and cT3 (19 %). The thyroid cartilage was invaded on pathology in 19 cases (8 %). CT's sensitivity was 10.5 %, specificity 94 %, positive predictive value 13 %, and negative predictive value 92 %. CT correctly predicted thyroid cartilage invasion in only two cases for an overall accuracy of 87 %. Among the false-positive CT's, tumors involving the anterior commissure were significantly over-represented (61.5 % vs. 27 %, p = .004). Tumors with decreased vocal fold (VF) mobility were significantly over-represented in the group of false-negatives (41 vs. 13 %, p = .0035). Preoperative CT was not effective in predicting thyroid cartilage invasion in these early- to mid-stage lesions, overestimating cartilage invasion for AC lesions and underestimating invasion for lesions with decreased VF mobility.

  6. Prognostic Value of 18F-FDG PET-CT in Nasopharyngeal Carcinoma: Is Dynamic Scanning Helpful?

    PubMed Central

    Huang, Bingsheng; Wong, Ching-Yee Oliver; Lai, Vincent; Kwong, Dora Lai-Wan; Khong, Pek-Lan

    2015-01-01

    Objectives. To evaluate the differences in prognostic values of static and dynamic PET-CT in nasopharyngeal carcinoma (NPC). Material and Methods. Forty-five patients who had static scan were recruited. Sixteen had dynamic scan. The primary lesions were delineated from standardized uptake value (SUV) maps from static scan and Ki maps from dynamic scan. The average follow-up lasted for 34 months. The patients who died or those with recurrence/residual disease were considered “poor outcome”; otherwise they were considered “good outcome.” Fisher's exact test and ROC analysis were used to evaluate the prognostic value of various factors. Results. Tumor volume thresholded by 40% of maximal SUV (VOLSUV40) significantly predicted treatment outcome (p = 0.024) in the whole cohort. In 16 patients with dynamic scan, all parameters by dynamic scan were insignificant in predicting the outcome. The combination of maximal SUV, maximal Ki, VOLSUV40, and VOLKi37 (the tumor volume thresholded by 37% maximal Ki) achieved the highest predicting accuracy for treatment outcome with sensitivity, specificity, and accuracy of 100% in these 16 patients; however this improvement compared to VOLSUV40 was insignificant. Conclusion. Tumor volume from static scan is useful in NPC prognosis. However, the role of dynamic scanning was not justified in this small cohort. PMID:26064927

  7. Children, CT Scan and Radiation

    PubMed Central

    Bajoghli, Morteza; Bajoghli, Farshad; Tayari, Nazila; Rouzbahani, Reza

    2010-01-01

    Children are more sensitive to radiation than adults. Computerized tomography (CT) consists of 25 % of all medical imaging. It was estimated that more than 2% of all carcinomas in the USA are due to CT scans. There is an ongoing focus on the reduction of CT scan radiation dose. Awareness about risk-benefits of CT has increased. Reduction of radiological exam is an important issue because the accumulation effects of radiation can be hazardous. In addition, proper protocol should be followed for diagnostic procedures of ionization radiation and computerized tomography. Effective radiation dose should range from 0.8 to 10.5 millisievert. The same protocol should be followed in different hospitals as well. Basic principles of radiation protection should be monitored. As much as possible, both technician and radiologist must be present during computerized tomography for children, and MRI and ultrasound should be replaced if possible. PMID:21566776

  8. 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.

  9. Esophageal carcinoma: CT findings

    SciTech Connect

    Quint, L.E.; Glazer, G.M.; Orringer, M.B.; Gross, B.H.

    1985-04-01

    Preoperative CT scans of 33 patients with esophageal cancer were reviewed to assess staging accuracy and define the role of CT in patients being considered for transhiatal blunt esophagectomy. Surgical and pathological verification was obtained in all cases. Only 13 tumors were staged correctly according to the TNM classification. In addition, CT was not useful in assessing resectability because of its low accuracy in evaluating aortic invasion and the fact that few patients had tracheobronchial or aortic invasion or hepatic metastases at presentation.

  10. Distant subcutaneous recurrence of a parathyroid carcinoma: abnormal uptakes in the (99m)Tc-sestamibi scan and (18)F-FDG PET/CT imaging.

    PubMed

    Kim, Sang Soo; Jeon, Yun Kyung; Lee, Soo Hyung; Kim, Bo Hyun; Kim, Seong Jang; Kim, Yong Ki; Kim, In Ju

    2014-05-01

    We report a rare case of distant subcutaneous parathyroid carcinoma recurrence. A 50-year-old woman was referred to our hospital because of sustained hypercalcemia despite surgical removal of a parathyroid carcinoma. A focal uptake in the upper mediastinal area was detected in a (99m)Tc-sestamibi scan, and (18)F-fluorodeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) imaging demonstrated a subcutaneous mass. She underwent tumor resection, and the pathological findings were consistent with a parathyroid carcinoma. The postoperative serum parathyroid hormone (PTH) level remained within normal limits. However, a new palpable solitary mass was identified in the upper portion of the left breast 1 year postoperatively. Both a (99m)Tc-sestamibi scan and (18)F-FDG PET/CT imaging revealed an abnormal lesion in the upper breast, and subsequent pathology reports confirmed parathyroid carcinoma metastasis. Serum PTH and calcium levels fell within normal ranges after tumor resection. Two subcutaneous recurrent lesions appeared likely due to tumor seeding during the previous endoscopic operation at a local hospital.

  11. Technical aspects of CT scanning.

    PubMed

    Maravilla, K R; Pastel, M S

    1978-01-01

    The advent of computed tomography (CT) has initiated a technological revolution which continues to the present time. A brief review of basic principles of CT scanning is presented, and the evolution of modern CT scanner systems is traced. Some early indications of future trends are also presented.

  12. Combined 18F-FDG and 11C-Methionine PET/CT scans in a case of metastatic hepatocellular carcinoma

    PubMed Central

    D’souza, Maria M.; Sharma, Rajnish; Jaimini, Abhinav; Saw, Sanjiv Kumar; Singh, Dinesh; Mondal, Anupam

    2014-01-01

    A 37-year-old male who underwent a central hepatectomy of the liver for hepatocellular carcinoma (HCC) was referred for an 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) study to rule out tumor recurrence or metastases. The scan showed a recurrent hepatic mass at the operative site, along with low-grade uptake in bilateral pulmonary metastases, mediastinal and hilar lymph nodes, and few skeletal sites. A non-FDG avid intracranial extradural mass was visualized in the right frontal lobe. The 11C-methionine PET/CT scan performed subsequently revealed a larger area of involvement at the primary site, along with widespread metastases to the lungs, mediastinal, hilar, and abdominal lymph nodes, and multiple skeletal sites. Further, dural metastasis with high tracer uptake was noted in the frontal region. To the best of our knowledge, this is the first case documented in the literature, wherein 11C-methionine PET/CT played a significant role in delineating the widespread dissemination, including the extremely rare dural involvement in a case of HCC. This report highlights the potential value of 11C-methionine PET/CT in assessing the hepatic and extrahepatic tumor burden in cases of HCC, especially in clinically unexpected locations. PMID:25210286

  13. 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 ( ...

  14. FDG-PET/CT in the evaluation of anal carcinoma

    SciTech Connect

    Cotter, Shane E.; Grigsby, Perry W. . E-mail: pgrigsby@wustl.edu; Siegel, Barry A.

    2006-07-01

    Purpose: Surgical staging and treatment of anal carcinoma has been replaced by noninvasive staging studies and combined modality therapy. In this study, we compare computed tomography (CT) and physical examination to [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the staging of carcinoma of the anal canal, with special emphasis on determination of spread to inguinal lymph nodes. Methods and Materials: Between July 2003 and July 2005, 41 consecutive patients with biopsy-proved anal carcinoma underwent a complete staging evaluation including physical examination, CT, and 2-FDG-PET/CT. Patients ranged in age from 30 to 89 years. Nine men were HIV-positive. Treatment was with standard Nigro regimen. Results: [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) detected 91% of nonexcised primary tumors, whereas CT visualized 59%. FDG-PET/CT detected abnormal uptake in pelvic nodes of 5 patients with normal pelvic CT scans. FDG-PET/CT detected abnormal nodes in 20% of groins that were normal by CT, and in 23% without abnormality on physical examination. Furthermore, 17% of groins negative by both CT and physical examination showed abnormal uptake on FDG-PET/CT. HIV-positive patients had an increased frequency of PET-positive lymph nodes. Conclusion: [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography detects the primary tumor more often than CT. FDG-PET/CT detects substantially more abnormal inguinal lymph nodes than are identified by standard clinical staging with CT and physical examination.

  15. Digital radiographic localization for CT scanning of the larynx

    SciTech Connect

    Silverman, P.M.; Korobkin, M.; Rauch, R.F.

    1983-12-01

    Computed tomography (CT) of the larynx is the preferred method for staging laryngeal carcinoma and assessing the extent of injury from trauma. The standard method of examination consists of 5 mm contiguous scans throughout the larynx in quiet respiration. Scans are performed with the patient supine with the neck slightly extended allowing the long axis of the larynx to be perpendicular to the scanning plane. A complete examination requires scanning from the supraglottic region (level of hyoid bone) to the subglottic region (level of cricoid cartlage). In the authors' experience when this method is used, multiple scans are performed cephalad to the level of interest because no upper limit of the examination is established before transaxial scans are done. We have used the lateral digital radiograph of the neck to identify specific landmarks so that the upper and lower limets of the examination can be established before scanning.

  16. Primary biliary carcinoma: CT evaluation

    SciTech Connect

    Thorsen, M.K.; Quiroz, F.; Lawson, T.L.; Smith, D.F.; Foley, W.D.; Steward, E.T.

    1984-08-01

    Fifty-three patients with documented primary biliary carcinoma were studied with computed tomography. Twenty-six patients had gallbladder carcinoma and 27 patients had carcinoma of the biliary ductal system. Ninety percent of patients with gallbladder cancer had an intraluminal mass. Local invasion into the liver was common. The majority of patients with biliary ductal carcinoma had dilated bile ducts, while only 50% of patients with gallbladder cancer had biliary ductal dilatation. The most common location of tumor involving the extrahepatic biliary ductal system was the distal common bile duct. This occurred in eight patients out of 27, or 30% of the cases.

  17. Localized peribronchial thickening: a CT sign of occult bronchogenic carcinoma

    SciTech Connect

    Foster, W.L. Jr.; Roberts, L. Jr.; McLendon, R.E.; Hill, R.C.

    1985-05-01

    The authors present a case with repeated positive sputum cytologies in which CT proved complementary to nonlocalizing endoscopies by identifying bronchogenic carcinoma as focal specimen provided precise pathologic correlation of the CT findings with a small squamous cell carcinoma.

  18. CT pancreatogram in carcinoma of the pancreas and chronic pancreatitis

    SciTech Connect

    Karasawa, E.; Goldberg, H.I.; Moss, A.A.; Federle, M.P.; London, S.S.

    1983-08-01

    CT has made it possible to determine the contour of the pancreatic duct, to measure its caliber, and to detect dilatation of the duct. CT scans of 75 patients with pancreatic carcinoma and of 45 patients with chronic pancreatitis were obtained. Dilatation of the pancreatic duct was seen in 56% of patients with carcinoma, and in 70% of those with tumors confined to the pancreatic head and body. Smooth dilatation (43%) or beaded dilatation (40%) were most commonly associated with carcinoma. Ductal dilatation was present in 58% of the patients with chronic pancreatitis, and irregular dilatation was seen in 73% of the patients in this group. About half of the patients who had irregular dilatation had calculi within the ducts. Eight cases of dilatation of the duct with no detectible pancreatic mass were seen in a subgroup of 13 patients who had small carcinomas of the pancreas (tumor size of 3 cm or less). Our findings indicate that a dilated pancreatic duct with a smooth contour and a ratio of duct to total gland width of 0.50 or greater suggests carcinoma as the underlying pathology.

  19. CT scan correlates of gesture recognition.

    PubMed Central

    Ferro, J M; Martins, I P; Mariano, G; Caldas, A C

    1983-01-01

    The ability to recognise gestures was studied in 65 left-hemispheric stroke patients whose lesions were located by CT scan. In the acute stage (first month) frontal lobe and basal ganglia were frequently involved in patients showing inability to recognise gestures. In the later (third to fourth month) and chronic stages (greater than 6 months) parietal lobe involvement was important; lesions causing gesture recognition impairment were larger, had more extensive and frequent parietal involvement and produced less temporal lobe damage than those causing aural comprehension defects. These findings are discussed in the light of recent models of cerebral localisation of complex functions. Images PMID:6644319

  20. Intercostal Artery Supplying Hepatocellular Carcinoma: Demonstration of a Tumor Feeder by C-arm CT and Multidetector Row CT

    SciTech Connect

    Kim, Hyo-Cheol Chung, Jin Wook; Lee, In Joon; An, Sangbu; Seong, Nak Jong; Son, Kyu Ri; Jae, Hwan Jun; Park, Jae Hyung

    2011-02-15

    This study was designed to describe tumor feeders from the intercostal artery supplying hepatocellular carcinoma (HCC) on C-arm CT and multidetector row CT. From March 2008 to May 2009, C-arm CT of the intercostal artery was prospectively performed in 24 HCC patients. Two interventional radiologists, who performed C-arm CT, evaluated tumor feeders on C-arm CT and multidetector row CT scans by consensus. In total, 35 intercostal arteries were examined by C-arm CT. All tumor feeders except one showed a sharp upward turn at or near the costochondral junction. On axial C-arm CT images, all tumor feeders were observed as an enhancing dot in the upper intercostal space along the diaphragm. On multidetector CT scans, 17 tumor feeders were observed and 18 were not. Tumor feeders from the intercostal artery are observed as an enhancing dot along the diaphragm on C-arm CT and can be seen on multidetector row CT in approximately half of patients.

  1. Comparison of CT and MRI in Diagnosis of Laryngeal Carcinoma with Anterior Vocal Commissure Involvement

    PubMed Central

    Wu, Jian-hui; Zhao, Jing; Li, Zeng-hong; Yang, Wei-qiang; Liu, Qi-hong; Yang, Zhi-yun; Liao, Bing; Li, Xiao-ling; Wang, Bin; Qin, Hao; Luo, Jie; Lv, Ke-xing; Wen, Wei-ping; Lei, Wen-bin

    2016-01-01

    This study aimed to compare the accuracy of CT and MRI in determining the invasion of thyroid cartilage by and the T staging of laryngeal carcinoma with anterior vocal commissure (AVC) involvement. A total of 26 cases of laryngeal carcinomas with AVC involvement from May 2012 to January 2014 underwent enhanced CT and MRI scan, out of whom 6 patients also underwent diffusion-weighted magnetic resonance imaging(DWI). T staging and thyroid cartilage involvement were evaluated. All the surgical specimens underwent serial section and were reviewed by two senior pathologists independently. When compared with pathologic staging, the accuracy was 88.46% (23/26) of MRI scan (with a 95% confidence interval 37~77%) and 57.69% (15/26) of CT scan (with a 95% confidence interval 70~98%), respectively (P < 0.01). We also reported three cases who were misdiagnosed on CT or MRI about either the thyroid cartilage was involved or not, and one case of preliminary study of DWI. Compared to CT, MRI exhibited a higher accuracy rate on T staging of laryngeal carcinomas with AVC involvement. Combined utility of CT and MRI could help improve the accuracy of assessment of thyroid cartilage involvement and T staging of laryngeal carcinomas with AVC involvement. PMID:27480073

  2. External ultrasonography of the neck does not add diagnostic value to integrated positron emission tomography-computed tomography (PET-CT) scanning in the diagnosis of cervical lymph node metastases in patients with esophageal carcinoma.

    PubMed

    Blom, R L G M; Vliegen, R F A; Schreurs, W M J; Belgers, H J; Stohr, I; Oostenbrug, L E; Sosef, M N

    2012-08-01

    One of the objectives of preoperative imaging in esophageal cancer patients is the detection of cervical lymph node metastases. Traditionally, external ultrasonography of the neck has been combined with computed tomography (CT) in order to improve the detection of cervical metastases. In general, integrated positron emission tomography-computed tomography (PET-CT) has been shown to be superior to CT or PET regarding staging and therefore may limit the role of external ultrasonography of the neck. The objective of this study was to determine the additional value of external ultrasonography of the neck to PET-CT. This study included all patients referred our center for treatment of esophageal carcinoma. Diagnostic staging was performed to determine treatment plan. Cervical lymph nodes were evaluated by external ultrasonography of the neck and PET-CT. In case of suspect lymph nodes on external ultrasonography or PET-CT, fine needle aspiration (FNA) was performed. Between 2008 and 2010, 170 out of 195 referred patients underwent both external ultrasonography of the neck and PET-CT. Of all patients, 84% were diagnosed with a tumor at or below the distal esophagus. In 140 of 170 patients, the cervical region was not suspect; no FNA was performed. Seven out of 170 patients had suspect nodes on both PET-CT and external ultrasonography. Five out of seven patients had cytologically confirmed malignant lymph nodes, one of seven had benign nodes, in one patient FNA was not performed; exclusion from esophagectomy was based on intra-abdominal metastases. In one out of 170 patients, PET-CT showed suspect nodes combined with a negative external ultrasonography; cytology of these nodes was benign. Twenty-two out of 170 patients had a negative PET-CT with suspect nodes on external ultrasonography. In 18 of 22 patients, cervical lymph nodes were cytologically confirmed benign; in four patients, FNA was not possible or inconclusive. At a median postoperative follow-up of 15 months

  3. Initial experience of Fag-PET/CT guided Imr of head-and-neck carcinoma

    SciTech Connect

    Wang Dian . E-mail: dwang@radonc.mcw.edu; Schultz, Christopher J.; Jursinic, Paul A.; Bialkowski, Mirek; Zhu, X. Ronald; Brown, W. Douglas; Rand, Scott D.; Michel, Michelle A.; Campbell, Bruce H.; Wong, Stuart; Li, X. Allen; Wilson, J. Frank

    2006-05-01

    Purpose: The purpose of this study is to evaluate the impact of {sup 18}F-fluorodeoxyglucose positron emission tomography (Fag-PET) fused with planning computed tomography (CT) on tumor localization, which guided intensity-modulated radiotherapy (Imr) of patients with head-and-neck carcinoma. Methods and Materials: From October 2002 through April 2005, we performed Fag-PET/CT guided Imr for 28 patients with head-and-neck carcinoma. Patients were immobilized with face masks that were attached with five fiducial markers. Fag-PET and planning CT scans were performed on the same flattop table in one session and were then fused. Target volumes and critical organs were contoured, and Imr plans were generated based on the fused images. Results: All 28 patients had abnormal increased uptake in Fag-PET/CT scans. PET/CT resulted in CT-based staging changes in 16 of 28 (57%) patients. PET/CT fusions were successfully performed and were found to be accurate with the use of the two commercial planning systems. Volume analysis revealed that the PET/CT-based gross target volumes (GTVs) were significantly different from those contoured from the CT scans alone in 14 of 16 patients. In addition, 16 of 28 patients who were followed for more than 6 months did not have any evidence of locoregional recurrence in the median time of 17 months. Conclusion: Fused images were found to be useful to delineate GTV required in IMRT planning. PET/CT should be considered for both initial staging and treatment planning in patients with head-and-neck carcinoma.

  4. Intracranial extramedullary hematopoiesis. CT and bone marrow scan findings

    SciTech Connect

    Urman, M.; O'Sullivan, R.A.; Nugent, R.A.; Lentle, B.C. )

    1991-06-01

    This case concerns a patient with intracranial extramedullary hematopoiesis (EH) suspected on a CT scan and subsequently confirmed with In-111 chloride and Tc-99m SC bone marrow scans. The bone marrow scans also provided additional information by demonstrating other sites of EH in the paravertebral tissues and bone marrow expansion into the distal extremities.

  5. Doctors Should Bone Up on CT Scan Cancer Risks

    MedlinePlus

    ... Medicine. For the study, the researchers surveyed doctors, radiologists and imaging technologists about radiation exposure from CT scans. They found the vast majority knew that one abdominal-pelvic CT increases patients' risk for cancer. But many didn't know how the dose ...

  6. Distinction between hemangioma of the liver and hepatocellular carcinoma: value of labeled RBC-SPECT scanning

    SciTech Connect

    Kudo, M.; Ikekubo, K.; Yamamoto, K.; Ibuki, Y.; Hino, M.; Tomita, S.; Komori, H.; Orino, A.; Todo, A.

    1989-05-01

    The role of adding single-photon emission CT (SPECT) to /sup 99m/Tc-labeled RBC imaging of the liver was evaluated by specifically focusing on the differentiation between hepatic hemangioma and hepatocellular carcinoma. Planar RBC imaging followed by blood-pool SPECT scanning was performed in 77 patients with a total of 108 hemangiomas and in 29 patients with a total of 46 hepatocellular carcinomas. All lesions were smaller than 5 cm in diameter. Thirty-six (33%) of 108 hemangiomas were detected by planar delayed RBC imaging, whereas 63 (58%) were detected by the delayed RBC-SPECT scan. The smallest hemangioma shown by delayed RBC-SPECT scanning was 1.4 cm in diameter, compared with 1.7 cm by planar RBC scanning. When confined to nodules larger than 1.4 cm in diameter, 42% of hemangiomas (36/85) were detected by planar delayed RBC imaging, whereas 74% (63/85) were detected by delayed RBC-SPECT. Increase in sensitivity was noted in nodules 2.1-4.0 cm in diameter. No hepatocellular carcinomas were shown by delayed RBC planar or SPECT scans. We concluded that with the addition of SPECT, the sensitivity of delayed RBC scans in the detection of small hemangiomas is considerably improved. Delayed RBC-SPECT scanning can be used to distinguish hemangioma from hepatocellular carcinoma.

  7. 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

  8. CT Scan of NASA Booster Nozzle

    SciTech Connect

    Schneberk, D; Perry, R; Thompson, R

    2004-07-27

    We scanned a Booster Nozzle for NASA with our 9 meV LINAC, AmSi panel scanner. Three scans were performed using different filtering schemes and different positions of the nozzle. The results of the scan presented here are taken from the scan which provided the best contrast and lowest noise of the three. Our inspection data shows a number of indications of voids in the outer coating of rubber/carbon. The voids are mostly on the side of the nozzle, but a few small voids are present at the ends of the nozzle. We saw no large voids in the adhesive layer between the Aluminum and the inner layer of carbon. This 3D inspection data did show some variation in the size of the adhesive layer, but none of the indications were larger than 3 pixels in extent (21 mils). We have developed a variety of contour estimation and extraction techniques for inspecting small spaces between layers. These tools might work directly on un-sectioned nozzles since the circular contours will fit with our tools a little better. Consequently, it would be useful to scan a full nozzle to ensure there are no untoward degradations in data quality, and to see if our tools would work to extract the adhesive layer.

  9. Dynamic CT scanning of spinal column trauma

    SciTech Connect

    Brown, B.M.; Brant-Zawadzki, M.; Cann, C.E.

    1982-12-01

    Dynamic sequential computed tomographic scanning with automatic table incrementation uses low milliampere-second technique to eliminate tube cooling delays between scanning slices and, thus, markedly shortens examination times. A total of 25 patients with spinal column trauma involving 28 levels were studied with dynamic scans and retrospectively reviewed. Dynamic studies were considerably faster than conventional spine examinations and yielded reliable diagnosis. Bone disruption and subluxation was accurately evaluated, and the use of intrathecal metrizamide in low doses allowed direct visualization of spinal cord or radicular compromise. Multiplanar image reformation was aided by the dynamic incrementation technique, since motion between slices (and the resulting misregistration artifact on image reformation) was minimized. A phantom was devised to test spatial resolution of computed tomography for objects 1-3 mm in size and disclosed minimal differences for dynamic and conventional computed tomographic techniques in resolving medium-to-high-contrast objects.

  10. CT Scanning Imaging Method Based on a Spherical Trajectory.

    PubMed

    Chen, Ping; Han, Yan; Gui, Zhiguo

    2016-01-01

    In industrial computed tomography (CT), the mismatch between the X-ray energy and the effective thickness makes it difficult to ensure the integrity of projection data using the traditional scanning model, because of the limitations of the object's complex structure. So, we have developed a CT imaging method that is based on a spherical trajectory. Considering an unrestrained trajectory for iterative reconstruction, an iterative algorithm can be used to realise the CT reconstruction of a spherical trajectory for complete projection data only. Also, an inclined circle trajectory is used as an example of a spherical trajectory to illustrate the accuracy and feasibility of this new scanning method. The simulation results indicate that the new method produces superior results for a larger cone-beam angle, a limited angle and tabular objects compared with traditional circle trajectory scanning.

  11. CT Scanning Imaging Method Based on a Spherical Trajectory

    PubMed Central

    2016-01-01

    In industrial computed tomography (CT), the mismatch between the X-ray energy and the effective thickness makes it difficult to ensure the integrity of projection data using the traditional scanning model, because of the limitations of the object’s complex structure. So, we have developed a CT imaging method that is based on a spherical trajectory. Considering an unrestrained trajectory for iterative reconstruction, an iterative algorithm can be used to realise the CT reconstruction of a spherical trajectory for complete projection data only. Also, an inclined circle trajectory is used as an example of a spherical trajectory to illustrate the accuracy and feasibility of this new scanning method. The simulation results indicate that the new method produces superior results for a larger cone-beam angle, a limited angle and tabular objects compared with traditional circle trajectory scanning. PMID:26934744

  12. [Usefulness of CT scan in the diagnosis of pulmonary aspergilloma].

    PubMed

    Gea, J; Arán, X; Sauleda, J; Broquetas, J M; Alegret, X; Bartrina, J

    1991-05-01

    Early diagnosis and precise anatomical localization of aspergillomas are essential for an effective treatment of their complications. We have evaluated the usefulness of thorax CT scan in the fulfillment of these objectives. Nine consecutive patients were studied with a presumable diagnosis of pulmonary aspergilloma. A thorax CT scan was performed in all patients (sections every 5 to 10 mm) in lying position and with lateral mobilizations. This technique allowed to rule out as fibrotic lesions some of the images previously attributed to mycetomas by conventional X-ray. On the other hand it helped to identify small size aspergillomas, to precise their localization and to demonstrate the possible communication between the main cavity and bronchial tree. In three patients who died in the period immediately following the study an excellent correlation between CT scan and underlying pathological lesions was observed. PMID:1891635

  13. Treatment of Alzheimer Disease With CT Scans

    PubMed Central

    Moore, Eugene R.; Hosfeld, Victor D.; Nadolski, David L.

    2016-01-01

    Alzheimer disease (AD) primarily affects older adults. This neurodegenerative disorder is the most common cause of dementia and is a leading source of their morbidity and mortality. Patient care costs in the United States are about 200 billion dollars and will more than double by 2040. This case report describes the remarkable improvement in a patient with advanced AD in hospice who received 5 computed tomography scans of the brain, about 40 mGy each, over a period of 3 months. The mechanism appears to be radiation-induced upregulation of the patient’s adaptive protection systems against AD, which partially restored cognition, memory, speech, movement, and appetite. PMID:27103883

  14. Comparison of full-scan and half-scan for cone beam breast CT imaging

    NASA Astrophysics Data System (ADS)

    Chen, Lingyun; Shaw, Chris C.; Lai, Chao-jen; Altunbas, Mustafa C.; Wang, Tianpeng; Tu, Shu-ju; Liu, Xinming

    2006-03-01

    The half-scan cone beam technique, requiring a scan for 180° plus detector width only, can help achieve both shorter scan time as well as higher exposure in each individual projection image. This purpose of this paper is to investigate whether half-scan cone beam CT technique can provide acceptable images for clinical application. The half-scan cone beam reconstruction algorithm uses modified Parker's weighting function and reconstructs from slightly more than half of the projection views for full-scan, giving out promising results. A rotation phantom, stationary gantry bench top system was built to conduct experiments to evaluate half-scan cone beam breast CT technique. A post-mastectomy breast specimen, a stack of lunch meat slices embedded with various sizes of calcifications and a polycarbonate phantom inserted with glandular and adipose tissue equivalents are imaged and reconstructed for comparison study. A subset of full-scan projection images of a mastectomy specimen were extracted and used as the half-scan projection data for reconstruction. The results show half-scan reconstruction algorithm for cone beam breast CT images does not significantly degrade image quality when compared with the images of same or even half the radiation dose level. Our results are encouraging, emphasizing the potential advantages in the use of half-scan technique for cone beam breast imaging.

  15. Cervix carcinoma and incidental finding of medullary thyroid carcinoma by 18F-FDG PET/CT--clinical case.

    PubMed

    Chaushev, Borislav; Bochev, Pavel; Klisarova, Anelia; Yordanov, Kaloyan; Encheva, Elitsa; Dancheva, Jivka; Yordanova, Cvetelina; Hristozov, Kiril; Krasnaliev, Ivan; Radev, Radoslav; Nenkov, Rumen

    2014-01-01

    Thyroid nodules are encountered in clinical practice during the diagnostic procedures or patients' follow-up due to other diseases quite far from the thyroid gland with prevalence 4-50% in general population, depending on age, diagnostic method and race. The prevalence of thyroid nodules increases with age and their clarification should be done for their adequate treatment. An 18F-FDG PET/CT was done with a PET/CT scanner (Philips Gemini TF), consisting of dedicated lutetium orthosilicate full ring PET scanner and 16 slice CT. The PET/CT scan of the whole-body revealed on the CT portion a hypodense nodular lesion in the left lobe of the thyroid gland with increased uptake of 18F-FDG on the PET with SUVmax 10.3 and demonstrated a complete response to the induction therapy of the main oncological disease of the patient--squamous cell carcinoma. This clinical case demonstrates that whole-body 18F-FDG-PET/CT has an increasingly important role in the early evaluation of thyroid cancer as a second independent malignant localization. Focal thyroid lesion with high risk of thyroid malignancy was incidentally found on 18F-FDG PET/CT. PMID:25088110

  16. 18F FDG PET/CT Evaluation of Patients with Ovarian Carcinoma

    PubMed Central

    Mittra, Erik S.; McDougall, I. Ross; Quon, Andrew; Gambhir, Sanjiv Sam

    2009-01-01

    Purpose The role of 18F FDG PET has been studied in ovarian carcinoma, but its sensitivity and specificity calculations are based on dedicated PET acquisition, not PET/CT in the majority of the published studies. Therefore, we were prompted to review our experience with PET/CT in the management of patients with ovarian carcinoma. Materials and methods This is a retrospective study of 43 women with ovarian carcinoma, 27–80 years old (average: 53.9 ± 7.8), who had whole-body PET/CT at our institution from Jan 1st, 2003 to Aug 31st, 2006. We reviewed the patients’ outcomes from medical records and compared them to the interpretation of the PET/CT scans. Sensitivity and specificity were calculated using a 2 × 2 table with pathology results (79.1% of the patients) or clinical follow-up (20.9% of the cases) as the gold standard. Confidence interval (CI) estimations were performed using the Wilson score method. Results All patients had advanced stage ovarian cancer and the study was requested for re-staging. A total of 60 scans were performed: 30 pts had 1 scan, 9 pts had 2 scans and 4 pts had 3 scans. The administered doses of 18F FDG ranged 381.1 – 769.6 MBq (average: 569.8 ± 73.3). PET/CT had a sensitivity of 88.4% (95% CI: 75.1–95.4) and a specificity of 88.2% (95% CI: 64.4–97.9) for detection of ovarian cancer. The SUV max of the detected lesions ranged 3–27 (average: 9.4±5.9). The CA-125 tumor marker ranged 3–935 kU/ml (average: 265.2) in patients with positive scans and 4–139 kU/ml (average: 17.1) in patients with negative scans. This difference was statistically significant (P value: 0.0242). Conclusion This study confirms the good results of 18F FDG PET/CT for identification of residual/recurrent ovarian cancer, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high risk ovarian cancer or rising values of tumor markers (CA-125), prior to selection of the most appropriate therapy

  17. Artifacts and pitfalls of high-resolution CT scans.

    PubMed

    Hahn, F J; Chu, W K; Anderson, J C; Dobry, C A

    1985-01-01

    Artifacts on CT images have been observed since the introduction of CT scanners. Some artifacts have been corrected with the improvement of technology and better understanding of the image formation and reconstruction algorithms. Some artifacts, however, are still observable in state-of-the-art high-resolution scans. Many investigations on CT artifacts have been reported. Some artifacts are obvious and some are similar to patterns commonly associated with pathological conditions. The present report summarizes some of the causes of artifacts and presents some artifacts that mimic pathology on clinical scans of the head and spine. It is the intention of this report to bring these artifacts and potential pitfalls to the attention of the radiologists so that misinterpretation can be avoided.

  18. [MRI and CT-scan in presumed benign ovarian tumors].

    PubMed

    Thomassin-Naggara, I; Bazot, M

    2013-12-01

    Radiological examinations are required for the assessment of complex or indeterminate ovarian masses, mainly using MRI and CT-scan. MRI provides better tissue characterization than Doppler ultrasound or CT-scan (LE2). Pelvic MRI is recommended in case of an indeterminate or complex ovarian ultrasonographic mass (grade B). The protocol of a pelvic MRI should include morphological T1 and T2 sequences (grade B). In case of solid portion, perfusion and diffusion sequences are recommended (grade C). In case of doubt about the diagnosis of ovarian origin, pelvic MRI is preferred over the CT-scan (grade C). MRI is the technique of choice for the difference between functional and organic ovarian lesion diagnosis (grade C). It can be useful in case of clinical diagnostic uncertainty between polycystic ovary syndrome and ovarian hyperstimulation and multilocular ovarian tumor syndrome (grade C). No MRI classification for ovarian masses is currently validated. The establishment of a presumption of risk of malignancy is required in a MRI report of adnexal mass with if possible a guidance on the histological diagnosis. In the absence of clinical or sonographic diagnosis, pelvic CT-scan is recommended in the context of acute painful pelvic mass in non-pregnant patients (grade C). It specifies the anomalies and allows the differential diagnosis with digestive and urinary diseases (LE4). Given the lack of data in the literature, the precautionary principle must be applied to the realization of a pelvic MRI in a pregnant patient. A risk-benefit balance should be evaluated case by case by the clinician and the radiologist and information should be given to the patient. In an emergency situation during pregnancy, pelvic MRI is an alternative to CT-scan for the exploration of acute pelvic pain in case of uncertain sonographic diagnosis (grade C).

  19. Thromboembolic Complications Following Spine Surgery Assessed with Spiral CT Scans

    PubMed Central

    Kim, Han Jo; Walcott-Sapp, Sarah; Adler, Ronald S.; Pavlov, Helene; Boachie-Adjei, Oheneba

    2010-01-01

    Spine surgery is associated with a significant risk of postoperative pulmonary embolism (PE) and/or deep vein thrombosis (DVT). The goal of this study was to determine which symptoms and risk factors were associated with spiral CT scans positive for PE and/or DVT in the postoperative spine surgery patient. We conducted a retrospective review of all spine patients who underwent a postoperative CT to rule out PE during the period of March 2004–February 2006. The type of surgical procedure, risk factors, symptoms prompting scan ordering, anticoagulation, and treatment were recorded. Logistic regression models were used to determine significant predictors of a positive CT in this patient population. Of the 3,331 patients that had spine surgery during the study period, 130 (3.9%) had a spiral CT scan to rule out PE and/or proximal DVT. Thirty-three of the 130 (25.4%) CT scans were positive for PE only, five (3.8%) for PE and DVT, and three (2.3%) for DVT only. Only 24.5% (32) patients had risk factors for thromboembolic disease, and of these, a history of PE and/or DVT was the only significant risk factor for a positive scan (p = 0.03). No presenting symptoms or demographic variables were noted to have a significant association with PE and/or DVT. The type of surgical procedure (i.e., anterior, posterior, and percutaneous) was not associated with an increased risk for PE and/or DVT. Patients who are undergoing spine surgery with a history of thromboembolic disease should be carefully monitored postoperatively and may benefit from more aggressive prophylaxis. PMID:22294955

  20. CT-detected solitary thyroid calcification: an important imaging feature for papillary carcinoma

    PubMed Central

    Yang, Tian-tian; Huang, Yong; Jing, Xu-quan; Gai, Xiu-juan; Li, Wen-wu

    2016-01-01

    Purpose To evaluate computed tomography (CT) detection of solitary thyroid calcification for identifying thyroid papillary carcinoma and to determine whether the predictive ability changes when the size increases after enhancement. Materials and methods CT scans on all 96 patients with thyroid nodules who underwent both enhanced CT examination of neck and thyroidectomy from 2014 to 2016 in the Shandong Cancer Hospital affiliated to Shandong University were reviewed. The cases without calcification and the cases with peripheral calcification, multiple coarse calcifications, or punctate calcification were excluded. Imaging features, including location and size of the lesions, were reviewed on plain and contrast-enhanced CT. The patients were grouped by histological results. The comparisons were evaluated by using Fisher’s exact test and binary logistic regression. Results The study population consisted of 96 patients (74 females, 22 males; mean age 49.8±11.3 years). Papillary thyroid carcinoma was observed in both solitary calcified thyroid nodules (85.4%) and solely coarse calcifications surrounded by low-density focus (58.2%). The difference was significant (P=0.006). Of 64 patients with an amplification of lesions after contrast enhancement, 58 (90.6%) were diagnosed with a malignant lesion. At the same time, of the 32 patients with no increase in size, 10 (31.2%) were diagnosed with carcinoma and 22 (68.8%) with nodular goiter. This difference was significant (P<0.001), and after binary logistic regression, increasing size was an independent risk factor for cancer. Conclusion Solitary calcified thyroid nodules detected on CT represent a high risk for papillary thyroid carcinoma, especially when the size of the lesions increases after contrast- enhanced CT. PMID:27785075

  1. Interobserver discrepancies in distance measurements from lumbar spine CT scans

    SciTech Connect

    Beers, G.J.; Carter, A.P.; Leiter, B.E.; Tilak, S.P.; Shah, R.R.

    1985-02-01

    Lumbar spine computed tomographic (CT) scans of 10 patients were examined independently at two levels by five experienced radiologists. At each level the minimum midline sagittal diameter was measured, and at each intervertebral space the left foramen was measured for its minimum diameter. Statistically significant differences were found between the measurements of different observers, differences that in a number of cases could have led to disagreement over whether or not stenosis was present. There were reasonably strong correlations between different observers' readings of midline sagittal diameters but generally not of foraminal diameters. Reasons for discrepancies between observers in spine CT measurements are reviewed briefly.

  2. Interactive annotation of textures in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Kockelkorn, Thessa T. J. P.; de Jong, Pim A.; Gietema, Hester A.; Grutters, Jan C.; Prokop, Mathias; van Ginneken, Bram

    2010-03-01

    This study describes a system for interactive annotation of thoracic CT scans. Lung volumes in these scans are segmented and subdivided into roughly spherical volumes of interest (VOIs) with homogeneous texture using a clustering procedure. For each 3D VOI, 72 features are calculated. The observer inspects the scan to determine which textures are present and annotates, with mouse clicks, several VOIs of each texture. Based on these annotations, a k-nearest-neighbor classifier is trained, which classifies all remaining VOIs in the scan. The algorithm then presents a slice with suggested annotations to the user, in which the user can correct mistakes. The classifier is retrained, taking into account these new annotations, and the user is presented another slice for correction. This process continues until at least 50% of all lung voxels in the scan have been classified. The remaining VOIs are classified automatically. In this way, the entire lung volume is annotated. The system has been applied to scans of patients with usual and non-specific interstitial pneumonia. The results of interactive annotation are compared to a setup in which the user annotates all predefined VOIs manually. The interactive system is 3.7 times as fast as complete manual annotation of VOIs and differences between the methods are similar to interobserver variability. This is a first step towards precise volumetric quantitation of texture patterns in thoracic CT in clinical research and in clinical practice.

  3. Pancreas tumor model in rabbit imaged by perfusion CT scans

    NASA Astrophysics Data System (ADS)

    Gunn, Jason; Tichauer, Kenneth; Moodie, Karen; Kane, Susan; Hoopes, Jack; Stewart, Errol E.; Hadway, Jennifer; Lee, Ting-Yim; Pereira, Stephen P.; Pogue, Brian W.

    2013-03-01

    The goal of this work was to develop and validate a pancreas tumor animal model to investigate the relationship between photodynamic therapy (PDT) effectiveness and photosensitizer drug delivery. More specifically, this work lays the foundation for investigating the utility of dynamic contrast enhanced blood perfusion imaging to be used to inform subsequent PDT. A VX2 carcinoma rabbit cell line was grown in the tail of the pancreas of three New Zealand White rabbits and approximately 3-4 weeks after implantation the rabbits were imaged on a CT scanner using a contrast enhanced perfusion protocol, providing parametric maps of blood flow, blood volume, mean transit time, and vascular permeability surface area product.

  4. The autonomic orienting response and CT scan findings in schizophrenia.

    PubMed

    Schnur, D B; Bernstein, A S; Mukherjee, S; Loh, J; Degreef, G; Reidel, J

    1989-01-01

    CT scan measures of prefrontal sulcal prominence, parieto-occipital sulcal prominence, ventricle-brain ratio (VBR), and third ventricle width (TVW) were examined in 24 schizophrenic patients who were grouped on the basis of their autonomic orienting response (OR) status. A two-component definition of the OR was used that required concordance across both electrodermal and finger pulse volume components for response status assignment. The nine OR responders had significantly greater TVW than the 15 OR nonresponders. Although OR responders had higher values also on the other CT scan measures, these differences were not significant. These findings are consistent with the possibility that OR responsiveness and nonresponsiveness are related to different pathological dimensions of schizophrenia. PMID:2487186

  5. Semi-automatic classification of textures in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Kockelkorn, Thessa T. J. P.; de Jong, Pim A.; Schaefer-Prokop, Cornelia M.; Wittenberg, Rianne; Tiehuis, Audrey M.; Gietema, Hester A.; Grutters, Jan C.; Viergever, Max A.; van Ginneken, Bram

    2016-08-01

    The textural patterns in the lung parenchyma, as visible on computed tomography (CT) scans, are essential to make a correct diagnosis in interstitial lung disease. We developed one automatic and two interactive protocols for classification of normal and seven types of abnormal lung textures. Lungs were segmented and subdivided into volumes of interest (VOIs) with homogeneous texture using a clustering approach. In the automatic protocol, VOIs were classified automatically by an extra-trees classifier that was trained using annotations of VOIs from other CT scans. In the interactive protocols, an observer iteratively trained an extra-trees classifier to distinguish the different textures, by correcting mistakes the classifier makes in a slice-by-slice manner. The difference between the two interactive methods was whether or not training data from previously annotated scans was used in classification of the first slice. The protocols were compared in terms of the percentages of VOIs that observers needed to relabel. Validation experiments were carried out using software that simulated observer behavior. In the automatic classification protocol, observers needed to relabel on average 58% of the VOIs. During interactive annotation without the use of previous training data, the average percentage of relabeled VOIs decreased from 64% for the first slice to 13% for the second half of the scan. Overall, 21% of the VOIs were relabeled. When previous training data was available, the average overall percentage of VOIs requiring relabeling was 20%, decreasing from 56% in the first slice to 13% in the second half of the scan.

  6. Colitis detection on abdominal CT scans by rich feature hierarchies

    NASA Astrophysics Data System (ADS)

    Liu, Jiamin; Lay, Nathan; Wei, Zhuoshi; Lu, Le; Kim, Lauren; Turkbey, Evrim; Summers, Ronald M.

    2016-03-01

    Colitis is inflammation of the colon due to neutropenia, inflammatory bowel disease (such as Crohn disease), infection and immune compromise. Colitis is often associated with thickening of the colon wall. The wall of a colon afflicted with colitis is much thicker than normal. For example, the mean wall thickness in Crohn disease is 11-13 mm compared to the wall of the normal colon that should measure less than 3 mm. Colitis can be debilitating or life threatening, and early detection is essential to initiate proper treatment. In this work, we apply high-capacity convolutional neural networks (CNNs) to bottom-up region proposals to detect potential colitis on CT scans. Our method first generates around 3000 category-independent region proposals for each slice of the input CT scan using selective search. Then, a fixed-length feature vector is extracted from each region proposal using a CNN. Finally, each region proposal is classified and assigned a confidence score with linear SVMs. We applied the detection method to 260 images from 26 CT scans of patients with colitis for evaluation. The detection system can achieve 0.85 sensitivity at 1 false positive per image.

  7. Double-low protocol for hepatic dynamic CT scan

    PubMed Central

    Zhang, Xiuli; Li, Shaodong; Liu, Wenlou; Huang, Ning; Li, Jingjing; Cheng, Li; Xu, Kai

    2016-01-01

    Abstract The radiation-induced carcinogenesis from computed tomography (CT) and iodine contrast agent induced nephropathy has attracted international attention. The reduction of the radiation dose and iodine intake in CT scan is always a direction for researchers to strive. The purpose of this study was to evaluate the feasibility of a “double-low” (i.e., low tube voltage and low-dose iodine contrast agent) scanning protocol for dynamic hepatic CT with the adaptive statistical iterative reconstruction (ASIR) in patients with a body mass index (BMI) of 18.5 to 27.9 kg/m2. A total of 128 consecutive patients with a BMI between 18.5 and 27.9 kg/m2 were randomly assigned into 3 groups according to tube voltage, iodine contrast agent, and reconstruction algorithms. Group A (the “double-low” protocol): 100 kVp tube voltage with 40% ASIR, iodixanol at 270 mg I/mL, group B: 120 kVp tube voltage with filtered back projection (FBP), iodixanol at 270 mg I/ mL, and group C: 120 kVp tube voltage with FBP, ioversol at 350 mg I/ mL. The volume CT dose index (CTDIvol) and effective dose (ED) in group A were lower than those in group B and C (all P < 0.01). The iodine intake in group A was decreased by approximately 26.5% than group C, whereas no statistical difference was observed between group A and B (P > 0.05). There was no significant difference of the CT values between group A and C (P > 0.05), which both showed higher CT values than that in group B (P < 0.001). However, no statistic difference was observed in the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), and image-quality scores among the 3 groups (all P > 0.05). Near-perfect consistency of the evaluation for group A, B, and C (Kenall's W = 0.921, 0.874, and 0.949, respectively) was obtained by the 4 readers with respect to the overall image quality. These results suggested that the “double-low” protocol with ASIR algorithm for multi-phase hepatic CT scan

  8. Preoperative CT evaluation of adrenal glands in non-small cell bronchogenic carcinoma

    SciTech Connect

    Nielsen, M.E. Jr.; Heaston, D.K.; Dunnick, N.R.; Korobkin, M.

    1982-08-01

    Preoperative chest computed tomographic (CT) scans in 84 patients with biopsy-proven non-small cell bronchogenic carcinoma were reviewed. At least one adrenal gland was visualized in 70 of these. Evidence of a solid adrenal mass was present in 18 (14.5%) glands in 15 (21.4%) patients. Percutaneous needle aspiration under CT guidance confirmed metastatic malignancy in the four patients who were biopsied. Because the documented presence of adrenal metastases in non-small cell lung cancer makes surgical resection or local irradiation inappropriate, it is recommended that both adrenal glands in their entirety be specifically included whenever a staging chest CT examination is performed in patients with such tumors. Percutaneous needle biopsy for pathologic confirmation of the nature of solid adrenal masses discovered in this process is also useful.

  9. Variation of quantitative emphysema measurements from CT scans

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Henschke, Claudia I.; Barr, R. Graham; Yankelevitz, David F.

    2008-03-01

    Emphysema is a lung disease characterized by destruction of the alveolar air sacs and is associated with long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema, and several measures have been introduced for the quantification of the extent of disease. In this paper we compare these measures for repeatability over time. The measures of interest in this study are emphysema index, mean lung density, histogram percentile, and the fractal dimension. To allow for direct comparisons, the measures were normalized to a 0-100 scale. These measures have been computed for a set of 2,027 scan pairs in which the mean interval between scans was 1.15 years (σ: 93 days). These independent pairs were considered with respect to three different scanning conditions (a) 223 pairs where both were scanned with a 5 mm slice thickness protocol, (b) 695 with the first scanned with the 5 mm protocol and the second with a 1.25 mm protocol, and (c) 1109 pairs scanned both times using a 1.25 mm protocol. We found that average normalized emphysema index and histogram percentiles scores increased by 5.9 and 11 points respectively, while the fractal dimension showed stability with a mean difference of 1.2. We also found, a 7 point bias introduced for emphysema index under condition (b), and that the fractal dimension measure is least affected by scanner parameter changes.

  10. Complications in CT-guided Procedures: Do We Really Need Postinterventional CT Control Scans?

    SciTech Connect

    Nattenmüller, Johanna Filsinger, Matthias Bryant, Mark Stiller, Wolfram Radeleff, Boris Grenacher, Lars Kauczor, Hans-Ullrich Hosch, Waldemar

    2013-06-19

    PurposeThe aim of this study is twofold: to determine the complication rate in computed tomography (CT)-guided biopsies and drainages, and to evaluate the value of postinterventional CT control scans.MethodsRetrospective analysis of 1,067 CT-guided diagnostic biopsies (n = 476) and therapeutic drainages (n = 591) in thoracic (n = 37), abdominal (n = 866), and musculoskeletal (ms) (n = 164) locations. Severity of any complication was categorized as minor or major. To assess the need for postinterventional CT control scans, it was determined whether complications were detected clinically, on peri-procedural scans or on postinterventional scans only.ResultsThe complication rate was 2.5 % in all procedures (n = 27), 4.4 % in diagnostic punctures, and 1.0 % in drainages; 13.5 % in thoracic, 2.0 % in abdominal, and 3.0 % in musculoskeletal procedures. There was only 1 major complication (0.1 %). Pneumothorax (n = 14) was most frequent, followed by bleeding (n = 9), paresthesia (n = 2), material damage (n = 1), and bone fissure (n = 1). Postinterventional control acquisitions were performed in 65.7 % (701 of 1,067). Six complications were solely detectable in postinterventional control acquisitions (3 retroperitoneal bleeds, 3 pneumothoraces); all other complications were clinically detectable (n = 4) and/or visible in peri-interventional controls (n = 21).ConclusionComplications in CT-guided interventions are rare. Of these, thoracic interventions had the highest rate, while pneumothoraces and bleeding were most frequent. Most complications can be detected clinically or peri-interventionally. To reduce the radiation dose, postinterventional CT controls should not be performed routinely and should be restricted to complicated or retroperitoneal interventions only.

  11. Uterine cervical carcinoma after therapy: CT and MR imaging findings.

    PubMed

    Jeong, Yong Yeon; Kang, Heoung Keun; Chung, Tae Woong; Seo, Jeong Jin; Park, Jin Gyoon

    2003-01-01

    Cervical carcinoma is one of the most frequent causes of death in women. Computed tomography (CT) and magnetic resonance (MR) imaging are the primary modalities for follow-up of treated cervical carcinoma. A normal vaginal cuff after hysterectomy appears as a smooth, low-signal-intensity muscular wall on T2-weighted MR images. Early (2-3 months after treatment) and significant decreases in the signal intensity and volume of the tumor at MR imaging indicate a good response to radiation therapy. Sites of recurrence are the pelvis, lymph nodes, and distant sites. Pelvic recurrence appears as a heterogeneously enhancing mass at contrast material-enhanced CT and often appears as a heterogeneous, high-signal-intensity mass at T2-weighted MR imaging. Lymph node recurrence ranges from scattered, minimally enlarged nodes to large, conglomerate nodal masses. Determination of neoplastic infiltration of lymph nodes is based on size; most researchers consider nodes greater than 1 cm in short-axis diameter to be metastatic. Distant metastases are usually due to recurrent disease and occur in the abdomen, thorax, and bone. Knowledge of the normal therapeutic changes and the spectrum of recurrent tumor in patients with cervical carcinoma is important for accurate interpretation of follow-up CT and MR images.

  12. Quantitative analysis of CT scans of ceramic candle filters

    SciTech Connect

    Ferer, M.V.; Smith, D.H.

    1996-12-31

    Candle filters are being developed to remove coal ash and other fine particles (<15{mu}m) from hot (ca. 1000 K) gas streams. In the present work, a color scanner was used to digitize hard-copy CT X-ray images of cylindrical SiC filters, and linear regressions converted the scanned (color) data to a filter density for each pixel. These data, with the aid of the density of SiC, gave a filter porosity for each pixel. Radial averages, density-density correlation functions, and other statistical analyses were performed on the density data. The CT images also detected the presence and depth of cracks that developed during usage of the filters. The quantitative data promise to be a very useful addition to the color images.

  13. The Place of FDG PET/CT in Renal Cell Carcinoma: Value and Limitations

    PubMed Central

    Liu, Yiyan

    2016-01-01

    Unlike for most other malignancies, application of FDG PET/CT is limited for renal cell carcinoma (RCC), mainly due to physiological excretion of 18F-fluoro-2-deoxy-2-d-glucose (FDG) from the kidneys, which decreases contrast between renal lesions and normal tissue, and may obscure or mask the lesions of the kidneys. Published clinical observations were discordant regarding the role of FDG PET/CT in diagnosing and staging RCC, and FDG PET/CT is not recommended for this purpose based on current national and international guidelines. However, quantitative FDG PET/CT imaging may facilitate the prediction of the degree of tumor differentiation and allows for prognosis of the disease. FDG PET/CT has potency as an imaging biomarker to provide useful information about patient’s survival. FDG PET/CT can be effectively used for postoperative surveillance and restaging with high sensitivity, specificity, and accuracy, as early diagnosis of recurrent/metastatic disease can drastically affect therapeutic decision and alter outcome of patients. FDG uptake is helpful for differentiating benign or bland emboli from tumor thrombosis in RCC patients. FDG PET/CT also has higher sensitivity and accuracy when compared with bone scan to detect RCC metastasis to the bone. FDG PET/CT can play a strong clinical role in the management of recurrent and metastatic RCC. In monitoring the efficacy of new target therapy such as tyrosine kinase inhibitors (TKIs) treatment for advanced RCC, FDG PET/CT has been increasingly used to assess the therapeutic efficacy, and change in FDG uptake is a strong indicator of biological response to TKI. PMID:27656421

  14. The Place of FDG PET/CT in Renal Cell Carcinoma: Value and Limitations

    PubMed Central

    Liu, Yiyan

    2016-01-01

    Unlike for most other malignancies, application of FDG PET/CT is limited for renal cell carcinoma (RCC), mainly due to physiological excretion of 18F-fluoro-2-deoxy-2-d-glucose (FDG) from the kidneys, which decreases contrast between renal lesions and normal tissue, and may obscure or mask the lesions of the kidneys. Published clinical observations were discordant regarding the role of FDG PET/CT in diagnosing and staging RCC, and FDG PET/CT is not recommended for this purpose based on current national and international guidelines. However, quantitative FDG PET/CT imaging may facilitate the prediction of the degree of tumor differentiation and allows for prognosis of the disease. FDG PET/CT has potency as an imaging biomarker to provide useful information about patient’s survival. FDG PET/CT can be effectively used for postoperative surveillance and restaging with high sensitivity, specificity, and accuracy, as early diagnosis of recurrent/metastatic disease can drastically affect therapeutic decision and alter outcome of patients. FDG uptake is helpful for differentiating benign or bland emboli from tumor thrombosis in RCC patients. FDG PET/CT also has higher sensitivity and accuracy when compared with bone scan to detect RCC metastasis to the bone. FDG PET/CT can play a strong clinical role in the management of recurrent and metastatic RCC. In monitoring the efficacy of new target therapy such as tyrosine kinase inhibitors (TKIs) treatment for advanced RCC, FDG PET/CT has been increasingly used to assess the therapeutic efficacy, and change in FDG uptake is a strong indicator of biological response to TKI.

  15. The Place of FDG PET/CT in Renal Cell Carcinoma: Value and Limitations.

    PubMed

    Liu, Yiyan

    2016-01-01

    Unlike for most other malignancies, application of FDG PET/CT is limited for renal cell carcinoma (RCC), mainly due to physiological excretion of 18F-fluoro-2-deoxy-2-d-glucose (FDG) from the kidneys, which decreases contrast between renal lesions and normal tissue, and may obscure or mask the lesions of the kidneys. Published clinical observations were discordant regarding the role of FDG PET/CT in diagnosing and staging RCC, and FDG PET/CT is not recommended for this purpose based on current national and international guidelines. However, quantitative FDG PET/CT imaging may facilitate the prediction of the degree of tumor differentiation and allows for prognosis of the disease. FDG PET/CT has potency as an imaging biomarker to provide useful information about patient's survival. FDG PET/CT can be effectively used for postoperative surveillance and restaging with high sensitivity, specificity, and accuracy, as early diagnosis of recurrent/metastatic disease can drastically affect therapeutic decision and alter outcome of patients. FDG uptake is helpful for differentiating benign or bland emboli from tumor thrombosis in RCC patients. FDG PET/CT also has higher sensitivity and accuracy when compared with bone scan to detect RCC metastasis to the bone. FDG PET/CT can play a strong clinical role in the management of recurrent and metastatic RCC. In monitoring the efficacy of new target therapy such as tyrosine kinase inhibitors (TKIs) treatment for advanced RCC, FDG PET/CT has been increasingly used to assess the therapeutic efficacy, and change in FDG uptake is a strong indicator of biological response to TKI. PMID:27656421

  16. Light scattering in optical CT scanning of Presage dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Adamovics, J.; Cheeseborough, J. C.; Chao, K. S.; Wuu, C. S.

    2010-11-01

    The intensity of the scattered light from the Presage dosimeters was measured using a Thorlabs PM100D optical power meter (Thorlabs Inc, Newton, NJ) with an optical sensor of 1 mm diameter sensitive area. Five Presage dosimeters were made as cylinders of 15.2 cm, 10 cm, 4 cm diameters and irradiated with 6 MV photons using a Varian Clinac 2100EX. Each dosimeter was put into the scanning tank of an OCTOPUS" optical CT scanner (MGS Research Inc, Madison, CT) filled with a refractive index matching liquid. A laser diode was positioned at one side of the water tank to generate a stationary laser beam of 0.8 mm width. On the other side of the tank, an in-house manufactured positioning system was used to move the optical sensor in the direction perpendicular to the outgoing laser beam from the dosimeters at an increment of 1 mm. The amount of scattered photons was found to be more than 1% of the primary light signal within 2 mm from the laser beam but decreases sharply with increasing off-axis distance. The intensity of the scattered light increases with increasing light attenuations and/or absorptions in the dosimeters. The scattered light at the same off-axis distance was weaker for dosimeters of larger diameters and for larger detector-to-dosimeter distances. Methods for minimizing the effect of the light scattering in different types of optical CT scanners are discussed.

  17. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. These views depict vertical slices from side to middle of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  18. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from a series of horizontal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  19. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view depict horizontal slices from top to bottom of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  20. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the specimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from three orthogonal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: Los Alamos National Laboratory and the University of Colorado at Boulder).

  1. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required.

  2. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required. PMID:16211320

  3. Comparison of SPECT/CT, MRI and CT in diagnosis of skull base bone invasion in nasopharyngeal carcinoma.

    PubMed

    Zhang, Shu-xu; Han, Peng-hui; Zhang, Guo-qian; Wang, Rui-hao; Ge, Yong-bin; Ren, Zhi-gang; Li, Jian-sheng; Fu, Wen-hai

    2014-01-01

    Early detection of skull base invasion in nasopharyngeal carcinoma (NPC) is crucial for correct staging, assessing treatment response and contouring the tumor target in radiotherapy planning, as well as improving the patient's prognosis. To compare the diagnostic efficacy of single photon emission computed tomography/computed tomography (SPECT/CT) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of skull base invasion in NPC. Sixty untreated patients with histologically proven NPC underwent SPECT/CT imaging, contrast-enhanced MRI and CT. Of the 60 patients, 30 had skull base invasion confirmed by the final results of contrast-enhanced MRI, CT and six-month follow-up imaging (MRI and CT). The diagnostic efficacy of the three imaging modalities in detecting skull base invasion was evaluated. The rates of positive findings of skull base invasion for SPECT/CT, MRI and CT were 53.3%, 48.3% and 33.3%, respectively. The sensitivity, specificity and accuracy were 93.3%, 86.7% and 90.0% for SPECT/CT fusion imaging, 96.7%, 100.0% and 98.3% for contrast-enhanced MRI, and 66.7%, 100.0% and 83.3% for contrast-enhanced CT. MRI showed the best performance for the diagnosis of skull base invasion in nasopharyngeal carcinoma, followed closely by SPECT/CT. SPECT/CT had poorer specificity than that of both MRI and CT, while CT had the lowest sensitivity.

  4. Mid-ventilation CT scan construction from four-dimensional respiration-correlated CT scans for radiotherapy planning of lung cancer patients

    SciTech Connect

    Wolthaus, Jochem; Schneider, Christoph; Sonke, Jan-Jakob; Herk, Marcel van; Belderbos, Jose; Rossi, Maddalena; Lebesque, Joos V.; Damen, Eugene M.F. . E-mail: e.damen@nki.nl

    2006-08-01

    Purpose: Four-dimensional (4D) respiration-correlated imaging techniques can be used to obtain (respiration) artifact-free computed tomography (CT) images of the thorax. Current radiotherapy planning systems, however, do not accommodate 4D-CT data. The purpose of this study was to develop a simple, new concept to incorporate patient-specific motion information, using 4D-CT scans, in the radiotherapy planning process of lung cancer patients to enable smaller error margins. Methods and Materials: A single CT scan was selected from the 4D-CT data set. This scan represented the tumor in its time-averaged position over the respiratory cycle (the mid-ventilation CT scan). To select the appropriate CT scan, two methods were used. First, the three-dimensional tumor motion was analyzed semiautomatically to calculate the mean tumor position and the corresponding respiration phase. An alternative automated method was developed to select the correct CT scan using the diaphragm motion. Results: Owing to hysteresis, mid-ventilation selection using the three-dimensional tumor motion had a tumor position accuracy (with respect to the mean tumor position) better than 1.1 {+-} 1.1 mm for all three directions (inhalation and exhalation). The accuracy in the diaphragm motion method was better than 1.1 {+-} 1.1 mm. Conventional free-breathing CT scanning had an accuracy better than 0 {+-} 3.9 mm. The mid-ventilation concept can result in an average irradiated volume reduction of 20% for tumors with a diameter of 40 mm. Conclusion: Tumor motion and the diaphragm motion method can be used to select the (artifact-free) mid-ventilation CT scan, enabling a significant reduction of the irradiated volume.

  5. To Scan or not to Scan: Consideration of Medical Benefit in the Justification of CT Scanning.

    PubMed

    McCollough, Cynthia H

    2016-03-01

    While there are ongoing debates with regard to the level of risk, if any, associated with medical imaging, the benefits from medical imaging exams are well documented. This forum article looks at outcome-based medical studies and guidance from expert panels in an effort to bring the benefits of medical imaging, specifically CT imaging, into focus. The position is taken that imaging, medical, and safety communities must not continue to discuss small hypothetical risks from ionizing radiation without emphasizing the large well-documented benefits from medical imaging exams that use ionizing radiation. PMID:26808885

  6. Unusual Adrenal and Brain Metastases From Follicular Thyroid Carcinoma Revealed by 131I SPECT/CT.

    PubMed

    Zhao, Zhen; Shen, Guo-hua; Liu, Bin; Kuang, An-ren

    2016-01-01

    The adrenal metastasis from differentiated thyroid carcinoma is uncommon. Metastatic involvement of both adrenal and brain in the same patient from differentiated thyroid carcinoma is rare. Here, we described an unusual case with iodine-avid lung, bone, adrenal, liver, and brain metastases from follicular thyroid carcinoma confirmed by 131I SPECT/CT. The utilization of SPECT/CT in thyroid cancer patients can detect the presence of metastases and also exclude potential false-positive lesions. Our case demonstrates that SPECT/CT is helpful in localizing and confirming metastatic lesions from differentiated thyroid carcinoma in rare and unusual sites.

  7. 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

    2016-01-01

    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

  8. 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.

  9. 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

  10. Adenoid cystic carcinoma of the trachea treated with PET-CT based intensity modulated radiotherapy.

    PubMed

    Haresh, Kunhi Parambath; Prabhakar, Ramachandran; Rath, Goura K; Sharma, Daya Nand; Julka, Pramod K; Subramani, V

    2008-07-01

    Primary tumors of the trachea are rare and are usually malignant in adults and benign in children. Adenoid cystic carcinoma, which is of salivary gland origin, account for about one thirds of adult primary tracheal tumors. A 49-year-old gentleman presented to us after undergoing a pneumonectomy elsewhere. Computed tomography scan of the thorax at our hospital showed a residual disease in the primary site, size of which was same as that in the preoperative scan. Because there was a compromised respiratory reserve due to pneumonectomy we decided to keep the radiation dose to the remaining lung as low as possible. We treated him by positron emission tomography-computed tomography (PET-CT) directed intensity modulated radiation therapy to a dose of 60 Gy in 30 Fractions over 6 weeks on a linear accelerator. PET helped in exact localization of the target on the planning CT. He tolerated the treatment very well. PET-CT done 1 year posttreatment showed no residual disease. Presently he is disease free with good pulmonary reserve. PMID:18594327

  11. Childhood CT scans linked to leukemia and brain cancer later in life

    Cancer.gov

    Children and young adults scanned multiple times by computed tomography (CT), a commonly used diagnostic tool, have a small increased risk of leukemia and brain tumors in the decade following their first scan.

  12. [Mucocele of the frontal sinus simulating metastasis of follicular thyroid carcinoma in an 131I scan].

    PubMed

    Duque Gallo, J J; Miguel Martínez, M B; Castillo López, L; Ruiz Pérez, E; Rubio Sanz, M J; Zamora Pérez, B; Casado Pérez, C; Rodríguez Salazar, A; Claver Criado, M; Calvo Del Castillo, J I

    1999-12-01

    The 131I scan is the preferred test in the follow-up of differentiated thyroid cancer patients although the many unusual circumstances of radioiodine uptake that can provide false positive results must be identified. We present the case of a woman who had undergone a thyroidectomy and was being treated for follicular carcinoma with an ablative dose os radioiodine whose pre- and post-treatment scans only revealed post-surgical residual thyroid tissues. A total body scan with 131I performed at one year demonstrated the success of the ablation. However, a left supra-orbital pathological deposit was observed during a subsequent routine 131I scan. The thyroglobulin serum level was below the sensitivity level for the assay (< 1 ng/ml) and the serum antibodies against thyroglobulin were not detected. A simple x-ray and bone scintigraphy were inconclusive. The CT and MRI revealed the presence of a mucocele in the left frontal sinus which was confirmed through histological examination. The possibility of a false positive results in an 131I scan must always be kept in mind, especially in the presence of atypical uptakes and undetectable thyroglobulin serum levels. As far as we know, only one similar case has been published previously.

  13. Stages of Adrenocortical Carcinoma

    MedlinePlus

    ... of Childhood Treatment for more information.) Having certain genetic conditions increases the risk of adrenocortical carcinoma. Anything ... can be a sign of disease. CT scan (CAT scan) : A procedure that makes a series of ...

  14. Value of repeat CT scans in low back pain and radiculopathy.

    PubMed

    Schroeder, Josh E; Barzilay, Yair; Kaplan, Leon; Itshayek, Eyal; Hiller, Nurith

    2016-02-01

    We assessed the clinical value of repeat spine CT scan in 108 patients aged 18-60 years who underwent repeat lumbar spine CT scan for low back pain or radiculopathy from January 2008 to December 2010. Patients with a neoplasm or symptoms suggesting underlying disease were excluded from the study. Clinical data was retrospectively reviewed. Index examinations and repeat CT scan performed at a mean of 24.3 ± 11.3 months later were compared by a senior musculoskeletal radiologist. Disc abnormalities (herniation, sequestration, bulge), spinal stenosis, disc space narrowing, and bony changes (osteophytes, fractures, other changes) were documented. Indications for CT scan were low back pain (60 patients, 55%), radiculopathy (46 patients, 43%), or nonspecific back pain (two patients, 2%). A total of 292 spine pathologies were identified in 98 patients (90.7%); in 10 patients (9.3%) no spine pathology was seen on index or repeat CT scan. At repeat CT scan, 269/292 pathologies were unchanged (92.1%); 10/292 improved (3.4%), 8/292 worsened (2.8%, disc herniation or spinal stenosis), and five new pathologies were identified. No substantial therapeutic change was required in patients with worsened or new pathology. Added diagnostic value from repeat CT scan performed within 2-3 years was rare in patients suffering chronic or recurrent low back pain or radiculopathy, suggesting that repeat CT scan should be considered only in patients with progressive neurologic deficits, new neurologic complaints, or signs implying serious underlying conditions.

  15. Knowledge Representation Of CT Scans Of The Head

    NASA Astrophysics Data System (ADS)

    Ackerman, Laurens V.; Burke, M. W.; Rada, Roy

    1984-06-01

    We have been investigating diagnostic knowledge models which assist in the automatic classification of medical images by combining information extracted from each image with knowledge specific to that class of images. In a more general sense we are trying to integrate verbal and pictorial descriptions of disease via representations of knowledge, study automatic hypothesis generation as related to clinical medicine, evolve new mathematical image measures while integrating them into the total diagnostic process, and investigate ways to augment the knowledge of the physician. Specifically, we have constructed an artificial intelligence knowledge model using the technique of a production system blending pictorial and verbal knowledge about the respective CT scan and patient history. It is an attempt to tie together different sources of knowledge representation, picture feature extraction and hypothesis generation. Our knowledge reasoning and representation system (KRRS) works with data at the conscious reasoning level of the practicing physician while at the visual perceptional level we are building another production system, the picture parameter extractor (PPE). This paper describes KRRS and its relationship to PPE.

  16. Study on Neurological Manifestations of Eclampsia & Findings of CT scan of Brain.

    PubMed

    Begum, F; Nahar, K; Ahmed, M U; Ferdousi, R A; Akter, F A; Rahman, M M

    2015-10-01

    This cross sectional study was carried out in the Department of Obstetrics & Gynaecology in Mymensingh Medical College Hospital during the period of January 2011 to December 2012 to evaluate neurological manifestations in eclampsia by CT scan of brain. A total 35 patients with eclampsia were studied, who underwent CT scan of brain in Radiology & Imaging Department of Mymensingh Medical College Hospital. The study patients were divided into two groups, those who had changes in brain on CT scan (Group A) & those who had no changes in brain on CT scan (Group B). Finally the study variables were compared between these two groups. Each selected patient fulfilling the criteria was sent to the department of Radiology & Imaging for CT scanning of brain. In antepartum cases of eclampsia CT scan of brain were done after delivery/ termination of pregnancy. In all cases, CT scan of brain was done within 72 hours of admission. Out of 35 patients total 85.72% had changes in brain on CT scan & 14.28% had no changes in brain on CT scan. Among them 45.72% patients had cerebral oedema, 37.14% had cerebral infarct & 2.86% patients had intracerebral haemorrhage. Comparison of neurological parameters were done & showed that there were statistically significant difference between the two groups regarding headache, visual disturbance, hypereflexia & depression of consciousness. There was no statistically significant difference regarding aphasia & hemiplegia between the two groups. So the CT scan of brain has been useful in demonstrating the lesion of brain in patients with eclampsia & also helpful to evaluate the neurological manifestations in eclampsia.

  17. Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

    SciTech Connect

    Neuwelt, E.A.; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

    1983-10-01

    Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. In eight of the 19 patients who had seizures after barrier disruption and enhanced CT scan, four subsequently had repeat procedures monitored by radionuclide scan alone. In only one of these patients was further seizure activity noted; a single focal motor seizure was observed. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented.

  18. A Simple Low-dose X-ray CT Simulation from High-dose Scan

    PubMed Central

    Zeng, Dong; Huang, Jing; Bian, Zhaoying; Niu, Shanzhou; Zhang, Hua; Feng, Qianjin; Liang, Zhengrong

    2015-01-01

    Low-dose X-ray computed tomography (CT) simulation from high-dose scan is required in optimizing radiation dose to patients. In this study, we propose a simple low-dose CT simulation strategy in sinogram domain using the raw data from high-dose scan. Specially, a relationship between the incident fluxes of low- and high- dose scans is first determined according to the repeated projection measurements and analysis. Second, the incident flux level of the simulated low-dose scan is generated by properly scaling the incident flux level of high-dose scan via the determined relationship in the first step. Third, the low-dose CT transmission data by energy integrating detection is simulated by adding a statistically independent Poisson noise distribution plus a statistically independent Gaussian noise distribution. Finally, a filtered back-projection (FBP) algorithm is implemented to reconstruct the resultant low-dose CT images. The present low-dose simulation strategy is verified on the simulations and real scans by comparing it with the existing low-dose CT simulation tool. Experimental results demonstrated that the present low-dose CT simulation strategy can generate accurate low-dose CT sinogram data from high-dose scan in terms of qualitative and quantitative measurements. PMID:26543245

  19. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  20. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    SciTech Connect

    Alva-Sánchez, Héctor

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  1. Effect of CAD on radiologists' detection of lung nodules on thoracic CT scans: observer performance study

    NASA Astrophysics Data System (ADS)

    Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Shi, Jiazheng; Cascade, Philip N.; Kazerooni, Ella A.; Zhou, Chuan; Wei, Jun; Chughtai, Aamer R.; Poopat, Chad; Song, Thomas; Nojkova, Jadranka S.; Frank, Luba; Attili, Anil

    2007-03-01

    The purpose of this study was to evaluate the effect of computer-aided diagnosis (CAD) on radiologists' performance for the detection of lung nodules on thoracic CT scans. Our computer system was designed using an independent training set of 94 CT scans in our laboratory. The data set for the observer performance study consisted of 48 CT scans. Twenty scans were collected from patient files at the University of Michigan, and 28 scans by the Lung Imaging Database Consortium (LIDC). All scans were read by multiple experienced thoracic radiologists to determine the true nodule locations, defined as any region identified by one or more expert radiologists as containing a nodule larger than 3 mm in diameter. Eighteen CT examinations were nodule-free, while the remaining 30 CT examinations contained a total of 73 nodules having a median size of 5.5 mm (range 3.0-36.4 mm). Four other study radiologists read the CT scans first without and then with CAD, and provided likelihood of nodule ratings for suspicious regions. Two of the study radiologists were fellowship trained in cardiothoracic radiology, and two were cardiothoracic radiology fellows. Freeresponse receiver-operating characteristic (FROC) curves were used to compare the two reading conditions. The computer system had a sensitivity of 79% (58/73) with an average of 4.9 marks per normal scan (88/18). Jackknife alternative FROC (JAFROC) analysis indicated that the improvement with CAD was statistically significant (p=0.03).

  2. An Effort to Develop an Algorithm to Target Abdominal CT Scans for Patients After Gastric Bypass.

    PubMed

    Pernar, Luise I M; Lockridge, Ryan; McCormack, Colleen; Chen, Judy; Shikora, Scott A; Spector, David; Tavakkoli, Ali; Vernon, Ashley H; Robinson, Malcolm K

    2016-10-01

    Abdominal CT (abdCT) scans are frequently ordered for Roux-en-Y gastric bypass (RYGB) patients presenting to the emergency department (ED) with abdominal pain, but often do not reveal intra-abdominal pathology. We aimed to develop an algorithm for rational ordering of abdCTs. We retrospectively reviewed our institution's RYGB patients presenting acutely with abdominal pain, documenting clinical and laboratory data, and scan results. Associations of clinical parameters to abdCT results were examined for outcome predictors. Of 1643 RYGB patients who had surgery between 2005 and 2015, 355 underwent 387 abdCT scans. Based on abdCT, 48 (12 %) patients required surgery and 86 (22 %) another intervention. No clinical or laboratory parameter predicted imaging results. Imaging decisions for RYGB patients do not appear to be amenable to a simple algorithm, and patient work-up should be based on astute clinical judgment.

  3. Full-Body CT Scans - What You Need to Know

    MedlinePlus

    ... FDA Submit search Popular Content Home Food Drugs Medical Devices Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary ... for assuring the safety and effectiveness of such medical devices, and it prohibits manufacturers of CT systems to ...

  4. Acquisition, preprocessing, and reconstruction of ultralow dose volumetric CT scout for organ-based CT scan planning

    SciTech Connect

    Yin, Zhye De Man, Bruno; Yao, Yangyang; Wu, Mingye; Montillo, Albert; Edic, Peter M.; Kalra, Mannudeep

    2015-05-15

    Purpose: Traditionally, 2D radiographic preparatory scan images (scout scans) are used to plan diagnostic CT scans. However, a 3D CT volume with a full 3D organ segmentation map could provide superior information for customized scan planning and other purposes. A practical challenge is to design the volumetric scout acquisition and processing steps to provide good image quality (at least good enough to enable 3D organ segmentation) while delivering a radiation dose similar to that of the conventional 2D scout. Methods: The authors explored various acquisition methods, scan parameters, postprocessing methods, and reconstruction methods through simulation and cadaver data studies to achieve an ultralow dose 3D scout while simultaneously reducing the noise and maintaining the edge strength around the target organ. Results: In a simulation study, the 3D scout with the proposed acquisition, preprocessing, and reconstruction strategy provided a similar level of organ segmentation capability as a traditional 240 mAs diagnostic scan, based on noise and normalized edge strength metrics. At the same time, the proposed approach delivers only 1.25% of the dose of a traditional scan. In a cadaver study, the authors’ pictorial-structures based organ localization algorithm successfully located the major abdominal-thoracic organs from the ultralow dose 3D scout obtained with the proposed strategy. Conclusions: The authors demonstrated that images with a similar degree of segmentation capability (interpretability) as conventional dose CT scans can be achieved with an ultralow dose 3D scout acquisition and suitable postprocessing. Furthermore, the authors applied these techniques to real cadaver CT scans with a CTDI dose level of less than 0.1 mGy and successfully generated a 3D organ localization map.

  5. Concepts and Analyses in the CT Scanning of Root Systems and Leaf Canopies: A Timely Summary.

    PubMed

    Lafond, Jonathan A; Han, Liwen; Dutilleul, Pierre

    2015-01-01

    Non-medical applications of computed tomography (CT) scanning have flourished in recent years, including in Plant Science. This Perspective article on CT scanning of root systems and leaf canopies is intended to be of interest to three categories of readers: those who have not yet tried plant CT scanning, and should find inspiration for new research objectives; readers who are on the learning curve with applications-here is helpful advice for them; and researchers with greater experience-the field is evolving quickly and it is easy to miss aspects. Our conclusion is that CT scanning of roots and canopies is highly demanding in terms of technology, multidisciplinarity and big-data analysis, to name a few areas of expertise, but eventually, the reward for researchers is directly proportional! PMID:26734022

  6. Concepts and Analyses in the CT Scanning of Root Systems and Leaf Canopies: A Timely Summary

    PubMed Central

    Lafond, Jonathan A.; Han, Liwen; Dutilleul, Pierre

    2015-01-01

    Non-medical applications of computed tomography (CT) scanning have flourished in recent years, including in Plant Science. This Perspective article on CT scanning of root systems and leaf canopies is intended to be of interest to three categories of readers: those who have not yet tried plant CT scanning, and should find inspiration for new research objectives; readers who are on the learning curve with applications—here is helpful advice for them; and researchers with greater experience—the field is evolving quickly and it is easy to miss aspects. Our conclusion is that CT scanning of roots and canopies is highly demanding in terms of technology, multidisciplinarity and big-data analysis, to name a few areas of expertise, but eventually, the reward for researchers is directly proportional! PMID:26734022

  7. Concepts and Analyses in the CT Scanning of Root Systems and Leaf Canopies: A Timely Summary.

    PubMed

    Lafond, Jonathan A; Han, Liwen; Dutilleul, Pierre

    2015-01-01

    Non-medical applications of computed tomography (CT) scanning have flourished in recent years, including in Plant Science. This Perspective article on CT scanning of root systems and leaf canopies is intended to be of interest to three categories of readers: those who have not yet tried plant CT scanning, and should find inspiration for new research objectives; readers who are on the learning curve with applications-here is helpful advice for them; and researchers with greater experience-the field is evolving quickly and it is easy to miss aspects. Our conclusion is that CT scanning of roots and canopies is highly demanding in terms of technology, multidisciplinarity and big-data analysis, to name a few areas of expertise, but eventually, the reward for researchers is directly proportional!

  8. Pictorial essay: CT scan of appendicitis and its mimics causing right lower quadrant pain

    PubMed Central

    Sharma, Monika; Agrawal, Anjali

    2008-01-01

    CT scanning is widely used in the diagnostic workup of right lower quadrant pain. While appendicitis remains the most frequent cause, a majority of patients referred for suspected appendicitis turn out to have alternative diagnoses or a normal CT study. The purpose of our pictorial essay is to present an overview of the CT findings of appendicitis and its common mimics and to highlight the features that provide clues to alternative diagnoses.

  9. Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

  10. Dual energy micro CT SkyScan 1173 for the characterization of urinary stone

    NASA Astrophysics Data System (ADS)

    Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

    2016-03-01

    Knowledge of the composition of urinary stones is an essential part to determine suitable treatments for patients. The aim of this research is to characterize the urinary stones by using dual energy micro CT SkyScan 11173. This technique combines high-energy and low- energy scanning during a single acquisition. Six human urinary stones were scanned in vitro using 80 kV and 120 kV micro CT SkyScan 1173. Projected images were produced by micro CT SkyScan 1173 and then reconstructed using NRecon (in-house software from SkyScan) to obtain a complete 3D image. The urinary stone images were analysed using CT analyser to obtain information of internal structure and Hounsfield Unit (HU) values to determine the information regarding the composition of the urinary stones, respectively. HU values obtained from some regions of interest in the same slice are compared to a reference HU. The analysis shows information of the composition of the six scanned stones obtained. The six stones consist of stone number 1 (calcium+cystine), number 2 (calcium+struvite), number 3 (calcium+cystine+struvite), number 4 (calcium), number 5 (calcium+cystine+struvite), and number 6 (calcium+uric acid). This shows that dual energy micro CT SkyScan 1173 was able to characterize the composition of the urinary stone.

  11. Treatment Option Overview (Adrenocortical Carcinoma)

    MedlinePlus

    ... of Childhood Treatment for more information.) Having certain genetic conditions increases the risk of adrenocortical carcinoma. Anything ... can be a sign of disease. CT scan (CAT scan) : A procedure that makes a series of ...

  12. Increase in dicentric chromosome formation after a single CT scan in adults

    PubMed Central

    Abe, Yu; Miura, Tomisato; Yoshida, Mitsuaki A.; Ujiie, Risa; Kurosu, Yumiko; Kato, Nagisa; Katafuchi, Atsushi; Tsuyama, Naohiro; Ohba, Takashi; Inamasu, Tomoko; Shishido, Fumio; Noji, Hideyoshi; Ogawa, Kazuei; Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Muto, Satoshi; Ohsugi, Jun; Suzuki, Hiroyuki; Ishikawa, Tetsuo; Kamiya, Kenji; Sakai, Akira

    2015-01-01

    Excess risk of leukemia and brain tumors after CT scans in children has been reported. We performed dicentric chromosome assay (DCAs) before and after CT scan to assess effects of low-dose ionizing radiation on chromosomes. Peripheral blood (PB) lymphocytes were collected from 10 patients before and after a CT scan. DCA was performed by analyzing either 1,000 or 2,000 metaphases using both Giemsa staining and centromere-fluorescence in situ hybridization (Centromere-FISH). The increment of DIC formation was compared with effective radiation dose calculated using the computational dosimetry system, WAZA-ARI and dose length product (DLP) in a CT scan. Dicentric chromosome (DIC) formation increased significantly after a single CT scan, and increased DIC formation was found in all patients. A good correlation between the increment of DIC formation determined by analysis of 2,000 metaphases using Giemsa staining and those by 2,000 metaphases using Centromere-FISH was observed. However, no correlation was observed between the increment of DIC formation and the effective radiation dose. Therefore, these results suggest that chromosome cleavage may be induced by one CT scan, and we recommend 2,000 or more metaphases be analyzed in Giemsa staining or Centromere-FISH for DCAs in cases of low-dose radiation exposure. PMID:26349546

  13. Increase in dicentric chromosome formation after a single CT scan in adults.

    PubMed

    Abe, Yu; Miura, Tomisato; Yoshida, Mitsuaki A; Ujiie, Risa; Kurosu, Yumiko; Kato, Nagisa; Katafuchi, Atsushi; Tsuyama, Naohiro; Ohba, Takashi; Inamasu, Tomoko; Shishido, Fumio; Noji, Hideyoshi; Ogawa, Kazuei; Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Muto, Satoshi; Ohsugi, Jun; Suzuki, Hiroyuki; Ishikawa, Tetsuo; Kamiya, Kenji; Sakai, Akira

    2015-01-01

    Excess risk of leukemia and brain tumors after CT scans in children has been reported. We performed dicentric chromosome assay (DCAs) before and after CT scan to assess effects of low-dose ionizing radiation on chromosomes. Peripheral blood (PB) lymphocytes were collected from 10 patients before and after a CT scan. DCA was performed by analyzing either 1,000 or 2,000 metaphases using both Giemsa staining and centromere-fluorescence in situ hybridization (Centromere-FISH). The increment of DIC formation was compared with effective radiation dose calculated using the computational dosimetry system, WAZA-ARI and dose length product (DLP) in a CT scan. Dicentric chromosome (DIC) formation increased significantly after a single CT scan, and increased DIC formation was found in all patients. A good correlation between the increment of DIC formation determined by analysis of 2,000 metaphases using Giemsa staining and those by 2,000 metaphases using Centromere-FISH was observed. However, no correlation was observed between the increment of DIC formation and the effective radiation dose. Therefore, these results suggest that chromosome cleavage may be induced by one CT scan, and we recommend 2,000 or more metaphases be analyzed in Giemsa staining or Centromere-FISH for DCAs in cases of low-dose radiation exposure. PMID:26349546

  14. Comparison of CT and PET-CT based planning of radiation therapy in locally advanced pancreatic carcinoma

    PubMed Central

    Topkan, Erkan; Yavuz, Ali A; Aydin, Mehmet; Onal, Cem; Yapar, Fuat; Yavuz, Melek N

    2008-01-01

    Background To compare computed tomography (CT) with co-registered positron emission tomography-computed tomography (PET-CT) as the basis for delineating gross tumor volume (GTV) in unresectable, locally advanced pancreatic carcinoma (LAPC). Methods Fourteen patients with unresectable LAPC had both CT and PET images acquired. For each patient, two three-dimensional conformal plans were made using the CT and PET-CT fusion data sets. We analyzed differences in treatment plans and doses of radiation to primary tumors and critical organs. Results Changes in GTV delineation were necessary in 5 patients based on PET-CT information. In these patients, the average increase in GTV was 29.7%, due to the incorporation of additional lymph node metastases and extension of the primary tumor beyond that defined by CT. For all patients, the GTVCT versus GTVPET-CT was 92.5 ± 32.3 cm3 versus 104.5 ± 32.6 cm3 (p = 0.009). Toxicity analysis revealed no clinically significant differences between two plans with regard to doses to critical organs. Conclusion Co-registration of PET and CT information in unresectable LAPC may improve the delineation of GTV and theoretically reduce the likelihood of geographic misses. PMID:18808725

  15. Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR)

    NASA Astrophysics Data System (ADS)

    Wang, Tonghe; Zhu, Lei

    2016-09-01

    Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an

  16. [Preliminary investigation on dynamic CT scan of intracranial tumors].

    PubMed

    Wu, E H

    1989-04-01

    74 patients with various intracranial tumors were studied by means of dynamic CT, among them 45 cases were confirmed by operation and pathology. In analyzing the time-density curve and the ratio of increase in CT number of the tumoral tissue to that in the arterial lumens (tissue-blood ratio, TBR), we found that: (1) Dynamic CT technique is safe and easy to perform suitable for out-patients; (2) The time-density curves in acoustic neurinoma, meningioma, glioma and metastatic tumors are different from each other because of difference in vascularity and the degree of B.B.B. breakdown. Meningioma curve shows a rapid rise to the peak followed by a subsequent plateau; (3) TBR at the peak time (TBRp) is useful as an index for tumor. Combined analysis of time-density curve and TBRp is helpful for tumor differentiation. PMID:2758930

  17. Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

    SciTech Connect

    Neuwelt, E.A; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

    1983-10-01

    Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented.

  18. Multimodal imaging of the human temporal bone: A comparison of CT and optical scanning techniques

    NASA Astrophysics Data System (ADS)

    Voie, Arne H.; Whiting, Bruce; Skinner, Margaret; Neely, J. Gail; Lee, Kenneth; Holden, Tim; Brunsden, Barry

    2003-10-01

    A collaborative effort between Washington University in St. Louis and Spencer Technologies in Seattle, WA has been undertaken to create a multimodal 3D reconstruction of the human cochlea and vestibular system. The goal of this project is to improve the accuracy of in vivo CT reconstructions of implanted cochleae, and to expand the knowledge of high-resolution anatomical detail provided by orthogonal-plane optical sectioning (OPFOS). At WUSL, computed tomography (CT) images of the cochlea are used to determine the position of cochlear implant electrodes relative to target auditory neurons. The cochlear implant position is determined using pre- and post-operative CT scans. The CT volumes are cross-registered to align the semicircular canals and internal auditory canal, which have a unique configuration in 3-D space. The head of a human body donor was scanned with a clinical CT device, after which the temporal bones were removed, fixed in formalin and trimmed prior to scanning with a laboratory Micro CT scanner. Following CT, the temporal bones were sent to the OPFOS Imaging Lab at Spencer Technologies for a further analysis. 3-D reconstructions of CT and OPFOS imaging modalities were compared, and results are presented. [Work supported by NIDCD Grants R44-03623-5 and R01-00581-13.

  19. The Role of CT Scanning in Multidimensional Phenotyping of COPD

    PubMed Central

    2011-01-01

    Background: COPD is a heterogeneous disease characterized by airflow obstruction and diagnosed by lung function. CT imaging is emerging as an important, noninvasive tool in phenotyping COPD. However, the use of CT imaging in defining the disease heterogeneity above lung function is not fully known. Methods: Seventy-five patients with COPD (58 men, 17 women) were studied with CT imaging and with measures of airway inflammation. Airway physiology and health status were also determined. Results: The presence of emphysema (EM), bronchiectasis (BE), and bronchial wall thickening (BWT) was found in 67%, 27%, and 27% of subjects, respectively. The presence of EM was associated with lower lung function (mean difference % FEV1, −20%; 95% CI, −28 to −11; P < .001). There was no difference in airway inflammation, exacerbation frequency, or bacterial load in patients with EM alone or with BE and/or BWT ± EM. The diffusing capacity of the lung for carbon monoxide/alveolar volume ratio was the most sensitive and specific parameter in identifying EM (area under the receiver operator characteristic curve, 0.87; 95% CI, 0.79-0.96). Physiologic cluster analysis identified three clusters, two of which were EM predominant and the third characterized by a heterogeneous combination of EM and BE. Conclusions: The application of CT imaging can be useful as a tool in the multidimensional approach to phenotyping patients with COPD. PMID:21454400

  20. 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.

  1. Relationship between Hounsfield Unit in CT Scan and Gray Scale in CBCT

    PubMed Central

    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. PMID:25093055

  2. The role of PET/CT scanning in radiotherapy planning.

    PubMed

    Jarritt, P H; Carson, K J; Hounsell, A R; Visvikis, D

    2006-09-01

    The introduction of functional data into the radiotherapy treatment planning process is currently the focus of significant commercial, technical, scientific and clinical development. The potential of such data from positron emission tomography (PET) was recognized at an early stage and was integrated into the radiotherapy treatment planning process through the use of image fusion software. The combination of PET and CT in a single system (PET/CT) to form an inherently fused anatomical and functional dataset has provided an imaging modality which could be used as the prime tool in the delineation of tumour volumes and the preparation of patient treatment plans, especially when integrated with virtual simulation. PET imaging typically using 18F-Fluorodeoxyglucose (18F-FDG) can provide data on metabolically active tumour volumes. These functional data have the potential to modify treatment volumes and to guide treatment delivery to cells with particular metabolic characteristics. This paper reviews the current status of the integration of PET and PET/CT data into the radiotherapy treatment process. Consideration is given to the requirements of PET/CT data acquisition with reference to patient positioning aids and the limitations imposed by the PET/CT system. It also reviews the approaches being taken to the definition of functional/tumour volumes and the mechanisms available to measure and include physiological motion into the imaging process. The use of PET data must be based upon a clear understanding of the interpretation and limitations of the functional signal. Protocols for the implementation of this development remain to be defined, and outcomes data based upon clinical trials are still awaited. PMID:16980683

  3. A review of patient dose and optimisation methods in adult and paediatric CT scanning.

    PubMed

    Dougeni, E; Faulkner, K; Panayiotakis, G

    2012-04-01

    An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along with tools that assist clinicians in the decision-making process. There is the potential to eliminate clinically non-indicated CT scans by replacing them with alternative examinations especially for children or patients receiving multiple CT scans.

  4. Predictors of Positive Head CT Scan and Neurosurgical Procedures After Minor Head Trauma

    PubMed Central

    Kisat, Mehreen; Zafar, Syed Nabeel; Latif, Asad; Villegas, Cassandra V.; Efron, David T.; Stevens, Kent A.; Haut, Elliott R; Schneider, Eric B.; Zafar, Hasnain; Haider, Adil H.

    2012-01-01

    Background There continues to be an ongoing debate regarding the utility of Head CT scans in patients with a normal Glasgow Coma Scale (GCS) after minor head injury. The objective of this study is to determine patient and injury characteristics that predict a positive head CT scan or need for a Neurosurgical Procedure (NSP) among patients with blunt head injury and a normal GCS. Materials and Methods Retrospective analysis of adult patients in the National Trauma Data Bank who presented to the ED with a history of blunt head injury and a normal GCS of 15. The primary outcomes were a positive head CT scan or a NSP. Multivariate logistic regression controlling for patient and injury characteristics was used to determine predictors of each outcome. Results Out of a total of 83,566 patients, 24,414 (29.2%) had a positive head CT scan and 3,476 (4.2%) underwent a NSP. Older patients and patients with a history of fall (as compared to a motor vehicle crash) were more likely to have a positive finding on a head CT scan. Male patients, African-Americans (as compared to Caucasians) and those who presented with a fall were more likely to have a NSP. Conclusions Older age, male gender, ethnicity and mechanism of injury are significant predictors of a positive finding on head CT scans and the need for neurosurgical procedures. This study highlights patient and injury specific characteristics that may help in identifying patients with supposedly minor head injury who will benefit from a head CT scan. PMID:21872271

  5. Expanded applications of CT. Helical scanning in five common acute conditions.

    PubMed

    Nipper, M L; Jacobson, L K

    2001-06-01

    Helical CT has become a valuable imaging tool for detection of pulmonary embolism, deep venous thrombosis, ureteral colic, acute small-bowel obstruction, and acute appendicitis. Generally, helical CT has good sensitivity and specificity values, and scans can be performed more quickly than previous gold standard diagnostic examinations for the conditions mentioned. In some cases, helical CT can also identify other findings that may be responsible for a patient's symptoms. One notable disadvantage of helical CT is the charge for the procedure, which in some circumstances can be considerably more costly than diagnostic examinations preferred previously. However, because helical CT can often obviate the need for other tests--and may consequently reduce hospital stays--this technology may have the ability to reduce overall expenditures. Cost of helical CT is therefore a multifaceted issue and requires further study before conclusions can be drawn.

  6. CT of multiple sclerosis: reassessment of delayed scanning with high doses of contrast material

    SciTech Connect

    Spiegel, S.M.; Vinuela, F.; Fox, A.J.; Pelz, D.M.

    1985-09-01

    A prospective study involving 87 patients was carried out to evaluate the necessity for a high dose of contrast material in addition to delayed computed tomographic (CT) scanning for optimal detection of the lesions of multiple sclerosis in the brain. In patients with either clinically definite multiple sclerosis or laboratory-supported definite multiple sclerosis, CT scans were obtained with a uniform protocol. Lesions consistent with multiple sclerosis were demonstrated on the second scan in 54 patients. In 36 of these 54 patients, the high-dose delayed scan added information. These results are quite similar to those of a previous study from this institution using different patients, in whom the second scan was obtained immediately after the bolus injection of contrast material containing 40 g of organically bound iodine. The lack of real difference in the results of the two studies indicate that the increased dose, not just the delay in scanning, is necessary for a proper study.

  7. Evaluation of geometrical effects of microneedles on skin penetration by CT scan and finite element analysis.

    PubMed

    Loizidou, Eriketi Z; Inoue, Nicholas T; Ashton-Barnett, Johnny; Barrow, David A; Allender, Chris J

    2016-10-01

    Computerized tomography scan (CT scan) imaging and finite element analysis were employed to investigate how the geometric composition of microneedles affects their mechanical strength and penetration characteristics. Simulations of microneedle arrays, comprising triangular, square and hexagonal microneedle base, revealed a linear dependence of the mechanical strength to the number of vertices in the polygon base. A laser-enabled, micromoulding technique was then used to fabricate 3×3 microneedle arrays, each individual microneedle having triangular, square or hexagonal base geometries. Their penetration characteristics into ex-vivo porcine skin, were investigated for the first time by CT scan imaging. This revealed greater penetration depths for the triangular and square-based microneedles, demonstrating CT scan as a powerful and reliable technique for studying microneedle skin penetration. PMID:27373753

  8. Three-Dimensions Segmentation of Pulmonary Vascular Trees for Low Dose CT Scans

    NASA Astrophysics Data System (ADS)

    Lai, Jun; Huang, Ying; Wang, Ying; Wang, Jun

    2016-12-01

    Due to the low contrast and the partial volume effects, providing an accurate and in vivo analysis for pulmonary vascular trees from low dose CT scans is a challenging task. This paper proposes an automatic integration segmentation approach for the vascular trees in low dose CT scans. It consists of the following steps: firstly, lung volumes are acquired by the knowledge based method from the CT scans, and then the data are smoothed by the 3D Gaussian filter; secondly, two or three seeds are gotten by the adaptive 2D segmentation and the maximum area selecting from different position scans; thirdly, each seed as the start voxel is inputted for a quick multi-seeds 3D region growing to get vascular trees; finally, the trees are refined by the smooth filter. Through skeleton analyzing for the vascular trees, the results show that the proposed method can provide much better and lower level vascular branches.

  9. Application of offset-CT scanning to the inspection of high power feeder lines and connections

    NASA Astrophysics Data System (ADS)

    Schneberk, Daniel; Maziuk, Robert; Soyfer, Boris; Shashishekhar, N.; Alreja, Rahul

    2016-02-01

    VJT is developing techniques and scanning methods for the in-situ Radiographic and Computed Tomographic inspection of underground high-power feeder cables. The goals for the inspection are to measure the 3D state of the cables and the cable-connections. Recent in-situ Digital Radiographic inspections performed by VJT have demonstrated the value of NDE inspection information for buried power lines. These NDE data have raised further questions as to the exact state of the cables and connections and pointed to the need for more 3D information of the type provided by volumetric CT scanning. VJT is pursuing a three phased approach to address the many issues involved in this type of inspection: 1) develop a high-power feeder-cable test-bed CT scanner, 2) acquire scans on underground feeder pipes that have been removed from service, and 3) from the work in 1) and 2) develop limited-angle CT scanning methods for extending in-situ Digital Radiography to volumetric CT measurements. To this end, VJT has developed and fielded a high-energy test-bed Gantry-type CT scanner (the source and detector move around the object) with a number of important properties. First, the geometry of the gantry-scans can be configured to match the techniques used in the in-situ radiographic inspection. The same X-ray source is employed as in portable Radiographic inspections, a 7.5 MeV Betatron coupled to a Perkin-Elmer Amorphous Silicon detector. Offset-CT scanning is employed as the high-power feeder line assembly is larger than the detector. A description of this scanner and the scan geometry will be presented showing the connection to in-situ radiography. Results from the CT scans of high-power feeder-cable specimens removed from service will be presented with a focus on the inspection potential of volumetric CT data on these assemblies. An evaluation of the scan performance properties of these data compared to the spectrum of life-cycle inspection issues will be presented. Continuing and

  10. Scan-rescan reproducibility of CT densitometric measures of emphysema

    NASA Astrophysics Data System (ADS)

    Chong, D.; van Rikxoort, E. M.; Kim, H. J.; Goldin, J. G.; Brown, M. S.

    2011-03-01

    This study investigated the reproducibility of HRCT densitometric measures of emphysema in patients scanned twice one week apart. 24 emphysema patients from a multicenter study were scanned at full inspiration (TLC) and expiration (RV), then again a week later for four scans total. Scans for each patient used the same scanner and protocol, except for tube current in three patients. Lung segmentation with gross airway removal was performed on the scans. Volume, weight, mean lung density (MLD), relative area under -950HU (RA-950), and 15th percentile (PD-15) were calculated for TLC, and volume and an airtrapping mask (RA-air) between -950 and -850HU for RV. For each measure, absolute differences were computed for each scan pair, and linear regression was performed against volume difference in a subgroup with volume difference <500mL. Two TLC scan pairs were excluded due to segmentation failure. The mean lung volumes were 5802 +/- 1420mL for TLC, 3878 +/- 1077mL for RV. The mean absolute differences were 169mL for TLC volume, 316mL for RV volume, 14.5g for weight, 5.0HU for MLD, 0.66p.p. for RA-950, 2.4HU for PD-15, and 3.1p.p. for RA-air. The <500mL subgroup had 20 scan pairs for TLC and RV. The R2 values were 0.8 for weight, 0.60 for MLD, 0.29 for RA-950, 0.31 for PD-15, and 0.64 for RA-air. Our results indicate that considerable variability exists in densitometric measures over one week that cannot be attributed to breathhold or physiology. This has implications for clinical trials relying on these measures to assess emphysema treatment efficacy.

  11. Preoperative CT-based nomogram for predicting overall survival in women with non-endometrioid carcinomas of the uterine corpus

    PubMed Central

    Lakhman, Yulia; Yakar, Derya; Goldman, Debra A.; Katz, Seth S.; Vargas, Hebert A.; Miccò, Maura; Zheng, Junting; Moskowitz, Chaya S.; Soslow, Robert A.; Hricak, Hedvig; Abu-Rustum, Nadeem R.; Sala, Evis

    2016-01-01

    Purpose To develop a preoperative CT-based nomogram for predicting overall survival (OS) in patients with non-endometrioid carcinomas of the uterine corpus. Methods Waiving informed consent, the institutional review board approved this HIPAA-compliant, retrospective study of 193 women with histopathologically proven uterine papillary serous carcinomas (UPSC), uterine clear cell carcinomas (UCCC), and uterine carcinosarcomas (UCS) who underwent primary surgical resection between May 1998 and December 2011, and had a preoperative CT ≤ 6 weeks before surgery. All CT scans were reviewed for local or/and regional tumor extent, presence of pelvic or/and paraaortic adenopathy, and presence of distant metastases. Univariate survival analysis was performed using log-rank test and Cox regression. Variables shown significant by the univariate analysis were evaluated with the multivariable Cox regression analysis and the results were used to create a nomogram for predicting OS. The predictive accuracy of the nomogram was assessed with the concordance probability index (c-index) and a 3-year calibration plot. Results Mean patient age was 67.2 years (range: 49.0–85.9); histology included UPSC (n=116), UCCC (n=27), and UCS (n=50). Median follow-up was 38.1 months (0.9–168.5 months). At multivariate analysis, patient age, ascites, and omental implants on CT were significant adverse predictors of OS and were used to build the nomogram. Concordance index for the nomogram was 0.640±0.028. Conclusion We developed a nomogram with a good concordance probability at predicting OS based on readily available pretreatment clinical and imaging characteristics. This preoperative nomogram has the potential to improve initial treatment planning and patient counseling. PMID:25549782

  12. Answers to Common Questions About the Use and Safety of CT Scans.

    PubMed

    McCollough, Cynthia H; Bushberg, Jerrold T; Fletcher, Joel G; Eckel, Laurence J

    2015-10-01

    Articles in the scientific literature and lay press over the past several years have implied that computed tomography (CT) may cause cancer and that physicians and patients must exercise caution in its use. Although there is broad agreement on the latter point--unnecessary medical tests of any type should always be avoided--there is considerable controversy surrounding the question of whether, or to what extent, CT scans can lead to future cancers. Although the doses used in CT are higher than those used in conventional radiographic examinations, they are still 10 to 100 times lower than the dose levels that have been reported to increase the risk of cancer. Despite the fact that at the low doses associated with a CT scan the risk either is too low to be convincingly demonstrated or does not exist, the magnitude of the concern among patients and some medical professionals that CT scans increase cancer risk remains unreasonably high. In this article, common questions about CT scanning and radiation are answered to provide physicians with accurate information on which to base their medical decisions and respond to patient questions. PMID:26434964

  13. Profile of CT scan output dose in axial and helical modes using convolution

    NASA Astrophysics Data System (ADS)

    Anam, C.; Haryanto, F.; Widita, R.; Arif, I.; Dougherty, G.

    2016-03-01

    The profile of the CT scan output dose is crucial for establishing the patient dose profile. The purpose of this study is to investigate the profile of the CT scan output dose in both axial and helical modes using convolution. A single scan output dose profile (SSDP) in the center of a head phantom was measured using a solid-state detector. The multiple scan output dose profile (MSDP) in the axial mode was calculated using convolution between SSDP and delta function, whereas for the helical mode MSDP was calculated using convolution between SSDP and the rectangular function. MSDPs were calculated for a number of scans (5, 10, 15, 20 and 25). The multiple scan average dose (MSAD) for differing numbers of scans was compared to the value of CT dose index (CTDI). Finally, the edge values of MSDP for every scan number were compared to the corresponding MSAD values. MSDPs were successfully generated by using convolution between a SSDP and the appropriate function. We found that CTDI only accurately estimates MSAD when the number of scans was more than 10. We also found that the edge values of the profiles were 42% to 93% lower than that the corresponding MSADs.

  14. Paired inspiratory-expiratory chest CT scans to assess for small airways disease in COPD

    PubMed Central

    2013-01-01

    Background Gas trapping quantified on chest CT scans has been proposed as a surrogate for small airway disease in COPD. We sought to determine if measurements using paired inspiratory and expiratory CT scans may be better able to separate gas trapping due to emphysema from gas trapping due to small airway disease. Methods Smokers with and without COPD from the COPDGene Study underwent inspiratory and expiratory chest CT scans. Emphysema was quantified by the percent of lung with attenuation < −950HU on inspiratory CT. Four gas trapping measures were defined: (1) Exp−856, the percent of lung < −856HU on expiratory imaging; (2) E/I MLA, the ratio of expiratory to inspiratory mean lung attenuation; (3) RVC856-950, the difference between expiratory and inspiratory lung volumes with attenuation between −856 and −950 HU; and (4) Residuals from the regression of Exp−856 on percent emphysema. Results In 8517 subjects with complete data, Exp−856 was highly correlated with emphysema. The measures based on paired inspiratory and expiratory CT scans were less strongly correlated with emphysema. Exp−856, E/I MLA and RVC856-950 were predictive of spirometry, exercise capacity and quality of life in all subjects and in subjects without emphysema. In subjects with severe emphysema, E/I MLA and RVC856-950 showed the highest correlations with clinical variables. Conclusions Quantitative measures based on paired inspiratory and expiratory chest CT scans can be used as markers of small airway disease in smokers with and without COPD, but this will require that future studies acquire both inspiratory and expiratory CT scans. PMID:23566024

  15. Single energy micro CT SkyScan 1173 for the characterization of urinary stone

    NASA Astrophysics Data System (ADS)

    Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

    2016-08-01

    A urinary stone is a solid piece of material produced from crystallization of excreted substances in the urine. Knowledge of the composition of urinary stones is essential to determine the suitable treatment for the patient. The aim of this research was to characterize urinary stones using single energy micro CT SkyScan 1173. Six human urinary stones were scanned in vitro using 80 kV in micro CT SkyScan 1173. The produced projection, images, were reconstructed using NRecon (in-house software from SkyScan). The images of urinary stones were analyzed using CT Analyser (CT An) to obtain information of the internal structure and the Hounsfield Unit (HU) value to determine the information regarding the composition of the urinary stones, respectively. The average HU values from certain region of interests in the same slice were compared with spectral curves of known materials from National Institute of Standards and Technology (NIST). From the analysis, the composition of the six scanned stones were obtained. Two stones are composed of cystine, two are composed of struvite, two other stones are composed of struvite+cystine. In conclusion, the single energy micro CT with 80 kV can be used identifying cystine and struvite urinary stone.

  16. Feasibility of iodine contrast enhanced CT-scan during a 18F-fluorodeoxyglucose Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Houzard, C.; Tychyj, C.; Morelec, I.; Ricard, F.; Got, P.; Cotton, F.; Giammarile, F.; Maintas, D.

    2009-06-01

    OBJECTIVE: this prospective study evaluates the feasibility in current clinical practice of contrast enhanced CT-scan for diagnosis purpose, performed during 18FDG PET-CT study with a PET/CT tomography. METHOD: 25 patients underwent FDG imaging for lymphoma staging. The PET scan was done immediately after the usual low dose CT (lCT). A second CT scan was consequently acquired, by using classical diagnosis CT parameters (dCT) and iodinated contrast. For each patient, all CT attenuation correction (CTAC) PET images were visually compared. Density in Hounsfield units (HU) and maximum Standardized Uptake Value (SUVmax) were then measured on different organs and up to 5 specific lymphoma localizations (total of 294 measurements). RESULTS: Visual analysis was similar for the 2 modalities, without discordant interpretation for the pathologic sites. SUVmax means and standard deviation of each organ for lCTAC and dCTAC were comparable. The equation of the fitted multiple linear regression model was: dCT=0.0748191 + 1.17024*lCT (98.71%; p < 0.01). CONCLUSION: These first results allow the use of injected CT scan, before the PET scan acquisition for lymphoma staging with this PET-CT scan, not affected by the height atomic number and elevated density. A great benefit is therefore obtained on diagnostic, logistic and radioprotection purposes.

  17. CT Scans of Cores Metadata, Barrow, Alaska 2015

    DOE Data Explorer

    Katie McKnight; Tim Kneafsey; Craig Ulrich

    2015-03-11

    Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

  18. CT Hounsfield Numbers of Soft Tissues on Unenhanced Abdominal CT Scans: Variability Between Two Different Manufacturers’ MDCT Scanners

    PubMed Central

    Lamba, Ramit; McGahan, John P.; Corwin, Michael T.; Li, Chin-Shang; Tran, Tien; Seibert, J. Anthony; Boone, John M.

    2016-01-01

    OBJECTIVE The purpose of this study is to determine whether Hounsfield numbers of soft tissues on unenhanced abdominal CT of the same patient vary on repeat scans done on two different manufacturers’ MDCT scanners. MATERIALS AND METHODS A database search was performed to identify patients older than 18 years who underwent unenhanced CT of the abdomen and pelvis performed both on a Volume CT (GE Healthcare) and a Definition AS Plus (Siemens Healthcare) 64-MDCT scanner within 12 months of each other. After excluding those patients for whom Hounsfield unit measurements would be affected by mitigating factors, 48 patients (mean age, 58.8 years) were identified. Hounsfield unit measurements were obtained in nine different soft-tissue anatomic locations on each scan, and the location of these sites was kept identical on each scan pair. Data were analyzed to evaluate Hounsfield unit differences between these scanners. RESULTS In general, there was a low consistency in the Hounsfield unit measurements for each of these sites on scans obtained by the two scanners, with the subcutaneous fat in the left posterolateral flank showing the lowest correlation (intraclass correlation coefficient, 0.198). There were differences in the Hounsfield unit measurements obtained in all anatomic sites on scans obtained by both scanners. Mean Hounsfield unit measurements obtained on the Definition AS Plus scanner were lower than those obtained on the Volume CT scanner, with the intriguing exception of the anterior midline subcutaneous fat Hounsfield unit measurements, which were higher on the Definition AS Plus scanner. All differences were statistically significant (p < 0.05). CONCLUSION Hounsfield unit measurements for unenhanced abdominal soft tissues of the same patient vary between scanners of two common MDCT manufacturers. PMID:25341139

  19. Radionuclide liver and bone scanning in the evaluation of patients with endometrial carcinoma

    SciTech Connect

    Mettler, F.A. Jr.; Christie, J.H.; Garcia, J.F.; Baldwin, M.H.; Wicks, J.D.; Bartow, S.A.

    1981-12-01

    Staging bone scans or skeletal surveys were obtained of 97 patients with endometrial carcinoma. Of the 77 patients with Stage I or II disease, no metastases were identified at staging. Three patients in the entire series demonstrated bony metastases; all of these metastases were detectable by radionuclide bone scan and radiographic bone survey. Eighty-nine patients were examined with radionuclide liver/spleen scanning at the time of staging. Four of the 89 initial scans were interpreted as demonstrating hepatocellular disease, and all four patients had abnormal liver function studies. Only one patient demonstrated a possible hepatic metastasis at initial diagnosis. This patient also had abnormal liver function studies. Based on these results, bone surveys and radionuclide bone scans are not indicated as screening procedures in endometrial carcinoma. It is suggested that screening for liver metastases in patients with endometrial carcinoma is not warranted in patients with normal liver function studies.

  20. Normal adrenal glands in small cell lung carcinoma: CT-guided biopsy

    SciTech Connect

    Pagani, J.J.

    1983-05-01

    Twenty-four small cell lung carcinoma patients with morphologically normal adrenal glands by computed tomographic (CT) criteria underwent percutaneous thin-needle biopsy of their adrenal glands. Of 43 glands biopsied, 29 had adequate cellular material for interpretation. Five (17%) of the 29 glands were positive for metastases; the rest had negative biopsies. This series indicates an approximate 17% false-negative diagnosis rate by CT when staging the adrenal glands in patients with small cell lung carcinoma. It also demonstrates the utility of percutaneous needle biopsy as an investigational tool to further evaluate normal-sized adrenal glands in the oncologic patient.

  1. Surveillance of HCC Patients after Liver RFA: Role of MRI with Hepatospecific Contrast versus Three-Phase CT Scan-Experience of High Volume Oncologic Institute.

    PubMed

    Granata, Vincenza; Petrillo, Mario; Fusco, Roberta; Setola, Sergio Venanzio; de Lutio di Castelguidone, Elisabetta; Catalano, Orlando; Piccirillo, Mauro; Albino, Vittorio; Izzo, Francesco; Petrillo, Antonella

    2013-01-01

    Purpose. To compare the diagnostic accuracy of hepatospecific contrast-enhanced MRI versus triple-phase CT scan after radiofrequency ablation (RFA) in hepatocellular carcinoma (HCC) patients. Methods. Thirty-four consecutive HCC patients (42 hepatic nodules) were treated with percutaneous RFA and underwent MR and CT scans. All patients were enrolled in a research protocol that included CT with iodized contrast medium injection and MR with hepatospecific contrast medium injection. All patients were restaged within four weeks and at 3 months from ablation. The images were reviewed by four different radiologists to evaluate tumor necrosis, residual or recurrence disease, and evidence of new foci. Results. Thirty-two nodules were necrotic after treatment; 10 showed residual disease. Six new HCCs were identified. At first month followup CT has identified 34 necrotic lesions and 8 residual diseases; no new foci were recognized. At MRI instead, 32 complete necrotic lesions were identified, 10 lesions showed residual disease, and 2 new HCCs were found. At three months, CT demonstrated 33 completely necrotic lesions, 9 residual diseases, and 2 new HCCs. MR showed 31 complete necrotic lesions, 11 cases of residual disease, and 6 new HCCs. Conclusions. Hepatospecific contrast-enhanced MRI is more effective than multiphase CT in assessment of HCC treated with RFA. PMID:24324487

  2. SU-E-J-260: Quantitative Image Feature Analysis of Multiphase Liver CT for Hepatocellular Carcinoma (HCC) in Radiation Therapy

    SciTech Connect

    Choi, W; Wang, J; Lu, W; Kang, M

    2015-06-15

    Purpose: To identify the effective quantitative image features (radiomics features) for prediction of response, survival, recurrence and metastasis of hepatocellular carcinoma (HCC) in radiotherapy. Methods: Multiphase contrast enhanced liver CT images were acquired in 16 patients with HCC on pre and post radiation therapy (RT). In this study, arterial phase CT images were selected to analyze the effectiveness of image features for the prediction of treatment outcome of HCC to RT. Response evaluated by RECIST criteria, survival, local recurrence (LR), distant metastasis (DM) and liver metastasis (LM) were examined. A radiation oncologist manually delineated the tumor and normal liver on pre and post CT scans, respectively. Quantitative image features were extracted to characterize the intensity distribution (n=8), spatial patterns (texture, n=36), and shape (n=16) of the tumor and liver, respectively. Moreover, differences between pre and post image features were calculated (n=120). A total of 360 features were extracted and then analyzed by unpaired student’s t-test to rank the effectiveness of features for the prediction of response. Results: The five most effective features were selected for prediction of each outcome. Significant predictors for tumor response and survival are changes in tumor shape (Second Major Axes Length, p= 0.002; Eccentricity, p=0.0002), for LR, liver texture (Standard Deviation (SD) of High Grey Level Run Emphasis and SD of Entropy, both p=0.005) on pre and post CT images, for DM, tumor texture (SD of Entropy, p=0.01) on pre CT image and for LM, liver (Mean of Cluster Shade, p=0.004) and tumor texture (SD of Entropy, p=0.006) on pre CT image. Intensity distribution features were not significant (p>0.09). Conclusion: Quantitative CT image features were found to be potential predictors of the five endpoints of HCC in RT. This work was supported in part by the National Cancer Institute Grant R01CA172638.

  3. What to do when a smoker's CT scan is "normal"?: Implications for lung cancer screening.

    PubMed

    Zurawska, Joanna H; Jen, Rachel; Lam, Stephen; Coxson, Harvey O; Leipsic, Jonathon; Sin, Don D

    2012-05-01

    Lung cancer is the leading cause of cancer-related mortality in the United States and around the world. There are > 90 million current and ex-smokers in the United States who are at increased risk of lung cancer. The published data from the National Lung Screening Trial (NLST) suggest that yearly screening with low-dose thoracic CT scan in heavy smokers can reduce lung cancer mortality by 20% and all-cause mortality by 7%. However, to implement this program nationwide using the NLST inclusion and exclusion criteria would be extremely expensive, with CT scan costs alone > $2 billion per annum. In this article, we offer a possible low-cost strategy to risk-stratify smokers on the basis of spirometry measurements and emphysema scoring by radiologists on CT scans. PMID:22553261

  4. Renal angiomyolipoma: diagnosis with B-ultrasonography, CT scanning, DSA and its interventional treatment.

    PubMed

    Zheng, C; Feng, G; Yang, J; Liang, H; Tian, Z

    1996-01-01

    From 1989, 15 cases of renal angiomyolipoma (AML) have been diagnosed by ultrasonography. CT scanning and digital subtraction angiography (DSA) at our hospital. In 8 patients with uneven hyperechoes on B-mode ultrasonography (B-US) (8/15) and 7 with low density of fat on CT scanning (7/12) accurate diagnosis was established preoperatively. DSA revealed the "berry-like" pseudoaneurysms in the arterial phase (14 cases), the defined lucent area in the nephrogram phase (10 cases) and the "onion-peel appearances" during venous phases (8 cases), correct diagnosis was achieved in all patients. 8 cases were surgically treated and 7 treated by subselective embolization of renal artery. Effects in all cases were good. The diagnostic value of B-US, CT scanning, DSA and interventional treatment of AML was discussed. It was believed that the diagnosis with DSA was a technique with high specificity, and embolization therapy was simple and effective for AML. PMID:9389091

  5. 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

  6. NCICT: a computational solution to estimate organ doses for pediatric and adult patients undergoing CT scans.

    PubMed

    Lee, Choonsik; Kim, Kwang Pyo; Bolch, Wesley E; Moroz, Brian E; Folio, Les

    2015-12-01

    We developed computational methods and tools to assess organ doses for pediatric and adult patients undergoing computed tomography (CT) examinations. We used the International Commission on Radiological Protection (ICRP) reference pediatric and adult phantoms combined with the Monte Carlo simulation of a reference CT scanner to establish comprehensive organ dose coefficients (DC), organ absorbed dose per unit volumetric CT Dose Index (CTDIvol) (mGy/mGy). We also developed methods to estimate organ doses with tube current modulation techniques and size specific dose estimates. A graphical user interface was designed to obtain user input of patient- and scan-specific parameters, and to calculate and display organ doses. A batch calculation routine was also integrated into the program to automatically calculate organ doses for a large number of patients. We entitled the computer program, National Cancer Institute dosimetry system for CT(NCICT). We compared our dose coefficients with those from CT-Expo, and evaluated the performance of our program using CT patient data. Our pediatric DCs show good agreements of organ dose estimation with those from CT-Expo except for thyroid. Our results support that the adult phantom in CT-Expo seems to represent a pediatric individual between 10 and 15 years rather than an adult. The comparison of CTDIvol values between NCICT and dose pages from 10 selected CT scans shows good agreements less than 12% except for two cases (up to 20%). The organ dose comparison between mean and modulated mAs shows that mean mAs-based calculation significantly overestimates dose (up to 2.4-fold) to the organs in close proximity to lungs in chest and chest-abdomen-pelvis scans. Our program provides more realistic anatomy based on the ICRP reference phantoms, higher age resolution, the most up-to-date bone marrow dosimetry, and several convenient features compared to previous tools. The NCICT will be available for research purpose in the near future.

  7. CCD-based optical CT scanning of highly attenuating phantoms

    NASA Astrophysics Data System (ADS)

    Al-Nowais, Shamsa; Doran, Simon J.

    2009-05-01

    The introduction of optical computed tomography (optical-CT) offers economic and easy to use 3-D optical readout for gel dosimeters. However, previous authors have noted some challenges regarding the accuracy of such imaging techniques at high values of optical density. In this paper, we take a closer look at the 'cupping' artefact evident in both light-scattering polymer systems and highly light absorbing phantoms using our CCD-based optical scanner. In addition, a technique is implemented whereby the maximum measurable optical absorbance is extended to correct for any errors that may have occurred in the estimated value of the dark current or ambient light reaching the detector. The results indicate that for absorbance values up to 2.0, the optical scanner results have good accuracy, whereas this is not the case at high absorbance values for reasons yet to be explained.

  8. Radiation dose calculations for CT scans with tube current modulation using the approach to equilibrium function

    SciTech Connect

    Li, Xinhua; Zhang, Da; Liu, Bob

    2014-11-01

    Purpose: The approach to equilibrium function has been used previously to calculate the radiation dose to a shift-invariant medium undergoing CT scans with constant tube current [Li, Zhang, and Liu, Med. Phys. 39, 5347–5352 (2012)]. The authors have adapted this method to CT scans with tube current modulation (TCM). Methods: For a scan with variable tube current, the scan range was divided into multiple subscan ranges, each with a nearly constant tube current. Then the dose calculation algorithm presented previously was applied. For a clinical CT scan series that presented tube current per slice, the authors adopted an efficient approach that computed the longitudinal dose distribution for one scan length equal to the slice thickness, which center was at z = 0. The cumulative dose at a specific point was a summation of the contributions from all slices and the overscan. Results: The dose calculations performed for a total of four constant and variable tube current distributions agreed with the published results of Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)]. For an abdomen/pelvis scan of an anthropomorphic phantom (model ATOM 701-B, CIRS, Inc., VA) on a GE Lightspeed Pro 16 scanner with 120 kV, N × T = 20 mm, pitch = 1.375, z axis current modulation (auto mA), and angular current modulation (smart mA), dose measurements were performed using two lines of optically stimulated luminescence dosimeters, one of which was placed near the phantom center and the other on the surface. Dose calculations were performed on the central and peripheral axes of a cylinder containing water, whose cross-sectional mass was about equal to that of the ATOM phantom in its abdominal region, and the results agreed with the measurements within 28.4%. Conclusions: The described method provides an effective approach that takes into account subject size, scan length, and constant or variable tube current to evaluate CT dose to a shift-invariant medium. For a clinical CT scan

  9. Estimating Radiation Dose Metrics for Patients Undergoing Tube Current Modulation CT Scans

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle Lorin

    Computed tomography (CT) has long been a powerful tool in the diagnosis of disease, identification of tumors and guidance of interventional procedures. With CT examinations comes the concern of radiation exposure and the associated risks. In order to properly understand those risks on a patient-specific level, organ dose must be quantified for each CT scan. Some of the most widely used organ dose estimates are derived from fixed tube current (FTC) scans of a standard sized idealized patient model. However, in current clinical practice, patient size varies from neonates weighing just a few kg to morbidly obese patients weighing over 200 kg, and nearly all CT exams are performed with tube current modulation (TCM), a scanning technique that adjusts scanner output according to changes in patient attenuation. Methods to account for TCM in CT organ dose estimates have been previously demonstrated, but these methods are limited in scope and/or restricted to idealized TCM profiles that are not based on physical observations and not scanner specific (e.g. don't account for tube limits, scanner-specific effects, etc.). The goal of this work was to develop methods to estimate organ doses to patients undergoing CT scans that take into account both the patient size as well as the effects of TCM. This work started with the development and validation of methods to estimate scanner-specific TCM schemes for any voxelized patient model. An approach was developed to generate estimated TCM schemes that match actual TCM schemes that would have been acquired on the scanner for any patient model. Using this approach, TCM schemes were then generated for a variety of body CT protocols for a set of reference voxelized phantoms for which TCM information does not currently exist. These are whole body patient models representing a variety of sizes, ages and genders that have all radiosensitive organs identified. TCM schemes for these models facilitated Monte Carlo-based estimates of fully

  10. Reproducibility of 18F-FDG PET uptake measurements in head and neck squamous cell carcinoma on both PET/CT and PET/MR

    PubMed Central

    Fischer, B M; Aznar, M C; Hansen, A E; Vogelius, I R; Löfgren, J; Andersen, F L; Loft, A; Kjaer, A; Højgaard, L; Specht, L

    2015-01-01

    Objective: To investigate reproducibility of fluorine-18 fludeoxyglucose (18F-FDG) uptake on 18F-FDG positron emission tomography (PET)/CT and 18F-FDG PET/MR scans in patients with head and neck squamous cell carcinoma (HNSCC). Methods: 30 patients with HNSCC were included in this prospective study. The patients were scanned twice before radiotherapy treatment with both PET/CT and PET/MR. Patients were scanned on the same scanners, 3 days apart and according to the same protocol. Metabolic tumour activity was measured by the maximum and peak standardized uptake value (SUVmax and SUVpeak, respectively), and total lesion glycolysis from the metabolic tumour volume defined from ≥50% SUVmax. Bland–Altman analysis with limits of agreement, coefficient of variation (CV) from the two modalities were performed in order to test the reproducibility. Furthermore, CVs from SUVmax and SUVpeak were compared. The area under the curve from cumulative SUV–volume histograms were measured and tested for reproducibility of the distribution of 18F-FDG uptake. Results: 24 patients had two pre-treatment PET/CT scans and 21 patients had two pre-treatment PET/MR scans available for further analyses. Mean difference for SUVmax, peak and mean was approximately 4% for PET/CT and 3% for PET/MR, with 95% limits of agreement less than ±20%. CV was small (5–7%) for both modalities. There was no significant difference in CVs between PET/CT and PET/MR (p = 0.31). SUVmax was not more reproducible than SUVpeak (p = 0.09). Conclusion: 18F-FDG uptake in PET/CT and PET/MR is highly reproducible and we found no difference in reproducibility between PET/CT and PET/MR. Advances in knowledge: This is the first report to test reproducibility of PET/CT and PET/MR. PMID:25634069

  11. Overbeaming and overlapping of volume-scan CT with tube current modulation in a 320-detector row CT scanner

    NASA Astrophysics Data System (ADS)

    Liao, Ying-Lan; Chen, Yan-Shi; Lai, Nan-Ku; Chuang, Keh-Shih; Tsai, Hui-Yu

    2014-11-01

    The purpose of this study was to evaluate the performance of volume scan tube current modulation (VS-ATCM) with adaptive iterative dose reduction 3D (AIDR3D) technique in abdomen CT examinations. We scanned an elliptical cone-shaped phantom utilizing AIDR3D technique combined with VS-ATCM mode in a 320-detector row CT scanner. The image noise distributions with conventional filtered back-projction (FBP) technique and those with AIDR3D technique were compared. The radiation dose profile and tube current time product (mAs) in three noise levels of VS-ATCM modes were compared. The radiation beam profiles of five preset scan lengths were measured using Gafchromic film strips to assess the effects of overbeaming and everlapping. The results indicated that the image noises with AIDR3D technique was 13-74% lower than those in FBP technique. The mAs distributions can be a prediction for various abdominal sizes when undergoing a VS-ATCM mode scan. Patients can receive the radiation dose of overbeaming and overlapping during the VS-ATCM mode scans.

  12. Lung function in silica-exposed workers. A relationship to disease severity assessed by CT scan.

    PubMed

    Bégin, R; Ostiguy, G; Cantin, A; Bergeron, D

    1988-09-01

    To investigate the relationship of lung function, airflow limitation, and lung injury in silica-exposed workers, we analyzed the clinical, functional, and radiologic data of 94 long-term workers exposed in the granite industry or in foundries. The subjects were divided into four subsets based on chest roentgenogram and CT scan of the thorax: group 1 consisted of 21 subjects with category 0 chest roentgenogram and category 0 CT scan; group 2, 28 subjects with category E 1 on both chest roentgenogram and CT scan; group 3, 18 subjects with category E 1 on chest roentgenogram but with coalescence or conglomeration or both seen only on CT scan; and group 4, 27 subjects with category E 1 and coalescence or conglomeration or both on roentgenogram and CT scan. The groups did not differ in terms of age, height, cigarette smoking, or years of exposure. Lung volumes were significantly reduced only in group 4 (p less than 0.05). Lung compliance, diffusion capacity, and the rest-exercise P(A-a)O2 gradient were reduced in groups 3 and 4 (p less than 0.05). Expiratory flow rates were significantly reduced in groups 2, 3, and 4, with the lowest values in group 4. The expiratory flow rates in group 3 were significantly lower in group 3 than in group 2. These results support the concept that airflow in silica-exposed workers is significantly reduced when the disease is detectable on simple chest roentgenogram; coalescence or conglomeration or both on chest roentgenogram or CT scan is associated with significant loss of lung volumes, gas exchange function, and increased airflow obstruction.

  13. Clinical evaluation of semi-automatic landmark-based lesion tracking software for CT-scans

    PubMed Central

    2014-01-01

    Background To evaluate a semi-automatic landmark-based lesion tracking software enabling navigation between RECIST lesions in baseline and follow-up CT-scans. Methods The software automatically detects 44 stable anatomical landmarks in each thoraco/abdominal/pelvic CT-scan, sets up a patient specific coordinate-system and cross-links the coordinate-systems of consecutive CT-scans. Accuracy of the software was evaluated on 96 RECIST lesions (target- and non-target lesions) in baseline and follow-up CT-scans of 32 oncologic patients (64 CT-scans). Patients had to present at least one thoracic, one abdominal and one pelvic RECIST lesion. Three radiologists determined the deviation between lesions’ centre and the software’s navigation result in consensus. Results The initial mean runtime of the system to synchronize baseline and follow-up examinations was 19.4 ± 1.2 seconds, with subsequent navigation to corresponding RECIST lesions facilitating in real-time. Mean vector length of the deviations between lesions’ centre and the semi-automatic navigation result was 10.2 ± 5.1 mm without a substantial systematic error in any direction. Mean deviation in the cranio-caudal dimension was 5.4 ± 4.0 mm, in the lateral dimension 5.2 ± 3.9 mm and in the ventro-dorsal dimension 5.3 ± 4.0 mm. Conclusion The investigated software accurately and reliably navigates between lesions in consecutive CT-scans in real-time, potentially accelerating and facilitating cancer staging. PMID:25609496

  14. Extraction of the Brain from CT Head Scans Based on Domain Knowledge

    SciTech Connect

    Qian Guoyu; Luo Suhuai; Jin, Jesse; Park, Mira; Nowinski, Wieslaw L.

    2007-11-02

    We present an automatic approach for an efficient brain extraction from CT head scans. Regions of interest are first set in each slice by applying thresholding and region growing. Next, the brain candidates are extracted by using three-dimensional region growing with a variable, anatomy-dependent structuring element. Domain knowledge, including Hounsfield unit ranges, anatomy, and image acquisition parameters, is applied. The proposed method has been applied automatically to 27 CT normal and pathological scans and has shown promising results. The average sensitivity, specificity and Dice's index for 5 cases are 99.6%, 99.4% and 98.7%, respectively.

  15. 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.

  16. Simulation of four-dimensional CT images from deformable registration between inhale and exhale breath-hold CT scans

    SciTech Connect

    Sarrut, David; Boldea, Vlad; Miguet, Serge; Ginestet, Chantal

    2006-03-15

    Purpose: We propose to simulate an artificial four-dimensional (4-D) CT image of the thorax during breathing. It is performed by deformable registration of two CT scans acquired at inhale and exhale breath-hold. Materials and methods: Breath-hold images were acquired with the ABC (Active Breathing Coordinator) system. Dense deformable registrations were performed. The method was a minimization of the sum of squared differences (SSD) using an approximated second-order gradient. Gaussian and linear-elastic vector field regularizations were compared. A new preprocessing step, called a priori lung density modification (APLDM), was proposed to take into account lung density changes due to inspiration. It consisted of modulating the lung densities in one image according to the densities in the other, in order to make them comparable. Simulated 4-D images were then built by vector field interpolation and image resampling of the two initial CT images. A variation in the lung density was taken into account to generate intermediate artificial CT images. The Jacobian of the deformation was used to compute voxel values in Hounsfield units. The accuracy of the deformable registration was assessed by the spatial correspondence of anatomic landmarks located by experts. Results: APLDM produced statistically significantly better results than the reference method (registration without APLDM preprocessing). The mean (and standard deviation) of distances between automatically found landmark positions and landmarks set by experts were 2.7(1.1) mm with APLDM, and 6.3(3.8) mm without. Interexpert variability was 2.3(1.2) mm. The differences between Gaussian and linear elastic regularizations were not statistically significant. In the second experiment using 4-D images, the mean difference between automatic and manual landmark positions for intermediate CT images was 2.6(2.0) mm. Conclusion: The generation of 4-D CT images by deformable registration of inhale and exhale CT images is

  17. Normalization of CT scans reconstructed with different kernels to reduce variability in emphysema measurements

    NASA Astrophysics Data System (ADS)

    Gallardo Estrella, L.; van Ginneken, B.; van Rikxoort, E. M.

    2013-03-01

    Chronic Obstructive Pulmonary Disease (COPD) is a lung disease characterized by progressive air flow limitation caused by emphysema and chronic bronchitis. Emphysema is quantified from chest computed tomography (CT) scans as the percentage of attentuation values below a fixed threshold. The emphysema quantification varies substantially between scans reconstructed with different kernels, limiting the possibilities to compare emphysema quantifications obtained from scans with different reconstruction parameters. In this paper we propose a method to normalize scans reconstructed with different kernels to have the same characteristics as scans reconstructed with a reference kernel and investigate if this normalization reduces the variability in emphysema quantification. The proposed normalization splits a CT scan into different frequency bands based on hierarchical unsharp masking. Normalization is performed by changing the energy in each frequency band to the average energy in each band in the reference kernel. A database of 15 subjects with COPD was constructed for this study. All subjects were scanned at total lung capacity and the scans were reconstructed with four different reconstruction kernels. The normalization was applied to all scans. Emphysema quantification was performed before and after normalization. It is shown that the emphysema score varies substantially before normalization but the variation diminishes after normalization.

  18. Interactive lung segmentation in abnormal human and animal chest CT scans

    SciTech Connect

    Kockelkorn, Thessa T. J. P. Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

    2014-08-15

    Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

  19. Metabolic super scan in F-FDG PET/CT imaging.

    PubMed

    Kim, Dae-Weung; Kim, Chang Guhn; Park, Soon-Ah; Jung, Sang-Ah; Yang, Sei-Hoon

    2010-08-01

    A 50-yr-old man presented with intermittent hemoptysis and was diagnosed small cell lung cancer. (18)F-FDG PET/CT for staging demonstrated extensive hypermetabolic lesions throughout the skeleton and liver. Interestingly, skeletal muscles of limbs, mediastinum, bowel, and especially brain showed very low FDG uptake. Because of some characteristics in common with super scan on skeletal scintigraphy, this case could be considered as 'metabolic super scan'.

  20. Treatment Options by Stage (Adrenocortical Carcinoma)

    MedlinePlus

    ... of Childhood Treatment for more information.) Having certain genetic conditions increases the risk of adrenocortical carcinoma. Anything ... can be a sign of disease. CT scan (CAT scan) : A procedure that makes a series of ...

  1. CT120A Acts as an Oncogene in Head and Neck Squamous Cell Carcinoma

    PubMed Central

    Baltaci, Elif; Ekizoglu, Seda; Sari, Elif; Karaman, Emin; Ulutin, Turgut; Buyru, Nur

    2015-01-01

    Squamous cell carcinoma of the head and neck (HNSCC) is among the most frequent cancers worldwide. The etiology and pathogenesis of HNSCC are influenced by multiple genetic factors in addition to environmental and lifestyle-related factors. However, the mechanism underlying the HNSCC is still far from clear. The membrane associated gene CT120 was previously identified from chromosome 17p13.3 as a lung cancer-associated gene. Its function as an activator of the Erk and Akt signaling pathways in human lung cancer cell lines suggested that CT120 has an oncogenic function. However, there is no data in the literature on the role of CT120 in any other cancer type. Therefore, the aim of this study was to determine the expression rate and probable function of CT120 in HNSCC. Tumor tissues from 50 patients were analyzed by real-time quantitative RT-PCR to investigate the expression rate and by direct sequencing to differentiate the CT120A and CT120B variants. CT120 overexpression was observed in 58% of tumors compared to non-cancerous tissue samples and this up-regulation was directly associated with the upregulation of the CT120A variant and with the stage of the disease (p=0.001). Our results indicate that the CT120 gene may function in the development of HNSCC. PMID:26535067

  2. Dual-resolution image reconstruction for region-of-interest CT scan

    NASA Astrophysics Data System (ADS)

    Jin, S. O.; Shin, K. Y.; Yoo, S. K.; Kim, J. G.; Kim, K. H.; Huh, Y.; Lee, S. Y.; Kwon, O.-K.

    2014-07-01

    In ordinary CT scan, so called full field-of-view (FFOV) scan, in which the x-ray beam span covers the whole section of the body, a large number of projections are necessary to reconstruct high resolution images. However, excessive x-ray dose is a great concern in FFOV scan. Region-of-interest (ROI) scan is a method to visualize the ROI in high resolution while reducing the x-ray dose. But, ROI scan suffers from bright-band artifacts which may hamper CT-number accuracy. In this study, we propose an image reconstruction method to eliminate the band artifacts in the ROI scan. In addition to the ROI scan with high sampling rate in the view direction, we get FFOV projection data with much lower sampling rate. Then, we reconstruct images in the compressed sensing (CS) framework with dual resolutions, that is, high resolution in the ROI and low resolution outside the ROI. For the dual-resolution image reconstruction, we implemented the dual-CS reconstruction algorithm in which data fidelity and total variation (TV) terms were enforced twice in the framework of adaptive steepest descent projection onto convex sets (ASD-POCS). The proposed method has remarkably reduced the bright-band artifacts at around the ROI boundary, and it has also effectively suppressed the streak artifacts over the entire image. We expect the proposed method can be greatly used for dual-resolution imaging with reducing the radiation dose, artifacts and scan time.

  3. Investigation of the potential causes of partial scan artifacts in dynamic CT myocardial perfusion imaging

    NASA Astrophysics Data System (ADS)

    Tao, Yinghua; Speidel, Michael; Szczykutowicz, Timothy; Chen, Guang-Hong

    2014-03-01

    In recent years, there have been several findings regarding CT number variations (partial scan artifact or PSA) across time in dynamic myocardial perfusion studies with short scan gated reconstruction. These variations are correlated with the view angle range corresponding to the short scan acquisition for a given cardiac phase, which can vary from one cardiac cycle to another due to the asynchrony between heart rate and gantry rotation speed. In this study, we investigate several potential causes of PSA, including noise, beam hardening and scatter, using numerical simulations. In addition, we investigate partial scan artifact in a single source 64-slice diagnostic CT scanner in vivo data sets, and report its effect on perfusion analysis. Results indicated that among all three factors investigated, scatter can cause obvious partial scan artifact in dynamic myocardial perfusion imaging. Further, scatter is a low frequency phenomenon and is not heavily dependent on the changing contrasts, as both the frequency method and the virtual scan method are effective in reducing partial scan artifact. However, PSA does not necessarily lead to different blood volume maps compared to the full scan, because these maps are usually generated with a curve fitting procedure.

  4. NOTE: An anatomically shaped lower body model for CT scanning of cadaver femurs

    NASA Astrophysics Data System (ADS)

    Tanck, Esther; Deenen, J. C. W.; Huisman, Henk Jan; Kooloos, Jan G.; Huizenga, Henk; Verdonschot, Nico

    2010-01-01

    Bone specific, CT-based finite element (FE) analyses have great potential to accurately predict the fracture risk of deteriorated bones. However, it has been shown that differences exist between FE-models of femora scanned in a water basin or scanned in situ within the human body, as caused by differences in measured bone mineral densities (BMD). In this study we hypothesized that these differences can be reduced by re-creating the patient CT-conditions by using an anatomically shaped physical model of the lower body. BMD distributions were obtained from four different femora that were scanned under three conditions: (1) in situ within the cadaver body, (2) in a water basin and (3) in the body model. The BMD of the three scanning protocols were compared at two locations: proximally, in the trabecular bone of the femoral head, and in the cortical bone of the femoral shaft. Proximally, no significant differences in BMD were found between the in situ scans and the scans in the body model, whereas the densities from the water basin scans were on average 10.8% lower than in situ. In the femoral shaft the differences between the three scanning protocols were insignificant. In conclusion, the body model better approached the in situ situation than a water basin. Future studies can use this body model to mimic patient situations and to develop protocols to improve the performance of the FE-models in actual patients.

  5. Study Finds Small Increase in Cancer Risk after Childhood CT Scans

    Cancer.gov

    A study published in the June 6, 2012, issue of The Lancet shows that radiation exposure from computed tomography (CT) scans in childhood results in very small but increased risks of leukemia and brain tumors in the first decade after exposure.

  6. The use of isodose curves on radiographs and on CT scans in interstitial brachytherapy.

    PubMed

    Warszawski, N; Bleher, M; Bratengeier, K; Bohndorf, W

    1992-07-01

    In brachytherapy an accurate dose distribution is usually not definable, and therefore not required. If flexible catheters are implanted, such as in head and neck cancer, resulting isodose curves only rarely fit exactly to radiographic films, and the target volume is not easily reconstructed. Usually no clear relationship exists between the three-dimensional (3D) dose distribution and target volume on the one hand and the two-dimensional (2D) radiographic films on the other. Dose distributions on radiographs are not sufficient to define the target absorbed dose and doses that critical areas will receive. A 3D imaging system, like computed tomographic (CT) scans, is needed in order to visualize underdosage inside the target volume and non-tolerable hot spots outside the tumour. Large-scale and expensive techniques exist to tackle these problems. Our inexpensive and verifiable approach to solve these problems combines localization radiographs with CT scans. Whereas tumour and critical areas are displayed on CT scans, flexible catheters loaded with dummy sources are best seen on radiographic films. With the help of a self-developed computer program, dose distributions are superimposed on CT scans. Doses to the target and critical organs are easily read and verified by external and internal detectors.

  7. Alignment of full and partial CT thoracic scans using bony structures

    NASA Astrophysics Data System (ADS)

    Gavrielides, Marios A.; Petrick, Nicholas; Myers, Kyle J.

    2006-03-01

    Diagnostic thoracic procedures using computed tomography (CT) often include comparisons of scans acquired with different slice thicknesses. In this manuscript, we investigated the potential for alignment of different CT scans from the same patient using skeletal knowledge of the thoracic region. Skeletal matching was selected because it is expected to be less susceptible to differences associated with patient breath hold, positioning and cardiac motion. Our method utilized the positioning of the ribs relative to the vertebra for matching. It also included matching the scapula when visible in the scans. Rib positioning was described by the angles formed between the vertebra centroid and combinations of pairs of rib centroids visible on each CT slice; this was used as the primary matching mechanism. Scapula morphology was described using a feature based on the local maxima of the distance transform. Since the scapula is not visible in all slices of a full scan, its description was limited to only defining the potential range of slices. A cost function incorporating the difference of features from rib positioning and scapula morphology between two slices was derived and used to match slices. The method was evaluated on an independent set of 10 pairs of full and partial CT scans. Assessment was based on whether or not slices containing known nodules between each pair of scans were overlapping after the alignment procedure. Results showed that the proposed metric correctly aligned 9 out of 10 scans. The preliminary results are encouraging for using this method as a first step towards temporal analysis of lung nodules.

  8. Pancreatic Cancer Tumor Size on CT Scan Versus Pathologic Specimen: Implications for Radiation Treatment Planning

    SciTech Connect

    Arvold, Nils D.; Niemierko, Andrzej; Mamon, Harvey J.; Hong, Theodore S.

    2011-08-01

    Purpose: Pancreatic cancer primary tumor size measurements are often discordant between computed tomography (CT) and pathologic specimen after resection. Dimensions of the primary tumor are increasingly relevant in an era of highly conformal radiotherapy. Methods and Materials: We retrospectively evaluated 97 consecutive patients with resected pancreatic cancer at two Boston hospitals. All patients had CT scans before surgical resection. Primary endpoints were maximum dimension (in millimeters) of the primary tumor in any direction as reported by the radiologist on CT and by the pathologist for the resected gross fresh specimen. Endoscopic ultrasound (EUS) findings were analyzed if available. Results: Of the patients, 87 (90%) had preoperative CT scans available for review and 46 (47%) had EUS. Among proximal tumors (n = 69), 40 (58%) had pathologic duodenal invasion, which was seen on CT in only 3 cases. The pathologic tumor size was a median of 7 mm larger compared with CT size for the same patient (range, -15 to 43 mm; p < 0.0001), with 73 patients (84%) having a primary tumor larger on pathology than CT. Endoscopic ultrasound was somewhat more accurate, with pathologic tumor size being a median of only 5 mm larger compared with EUS size (range, -15 to 35 mm; p = 0.0003). Conclusions: Computed tomography scans significantly under-represent pancreatic cancer tumor size compared with pathologic specimens in resectable cases. We propose a clinical target volume expansion formula for the primary tumor based on our data. The high rate of pathologic duodenal invasion suggests a risk of duodenal undercoverage with highly conformal radiotherapy.

  9. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    PubMed

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans. PMID:26832374

  10. Self-guided clinical cases for medical students based on postmortem CT scans of cadavers.

    PubMed

    Bohl, Michael; Francois, Webster; Gest, Thomas

    2011-07-01

    In the summer of 2009, we began full body computed tomography (CT) scanning of the pre-embalmed cadavers in the University of Michigan Medical School (UMMS) dissection lab. We theorized that implementing web-based, self-guided clinical cases based on postmortem CT (PMCT) scans would result in increased student appreciation for the clinical relevance of anatomy, increased knowledge of cross-sectional anatomy, and increased ability to identify common pathologies on CT scans. The PMCT scan of each cadaver was produced as a DICOM dataset, and then converted into a Quicktime movie file using Osirix software. Clinical cases were researched and written by the authors, and consist of at least one Quicktime movie of a PMCT scan surrounded by a novel navigation interface. To assess the value of these clinical cases we surveyed medical students at UMMS who are currently using the clinical cases in their coursework. Students felt the clinical cases increased the clinical relevance of anatomy (mean response 7.77/10), increased their confidence finding anatomical structures on CT (7.00/10), and increased their confidence recognizing common pathologies on CT (6.17/10). Students also felt these clinical cases helped them synthesize material from numerous courses into an overall picture of a given disease process (7.01/10). These results support the conclusion that our clinical cases help to show students why the anatomy they are learning is foundational to their other coursework. We would recommend the use of similar clinical cases to any medical school utilizing cadaver dissection as a primary teaching method in anatomy education.

  11. Analysis of chromosome translocation frequency after a single CT scan in adults

    PubMed Central

    Abe, Yu; Miura, Tomisato; Yoshida, Mitsuaki A.; Ujiie, Risa; Kurosu, Yumiko; Kato, Nagisa; Katafuchi, Atsushi; Tsuyama, Naohiro; Kawamura, Fumihiko; Ohba, Takashi; Inamasu, Tomoko; Shishido, Fumio; Noji, Hideyoshi; Ogawa, Kazuei; Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Muto, Satoshi; Ohsugi, Jun; Suzuki, Hiroyuki; Ishikawa, Tetsuo; Kamiya, Kenji; Sakai, Akira

    2016-01-01

    We recently reported an increase in dicentric chromosome (DIC) formation after a single computed tomography (CT) scan (5.78–60.27 mSv: mean 24.24 mSv) and we recommended analysis of 2000 metaphase cells stained with Giemsa and centromere-FISH for dicentric chromosome assay (DCA) in cases of low-dose radiation exposure. In the present study, we analyzed the frequency of chromosome translocations using stored Carnoy's-fixed lymphocyte specimens from the previous study; these specimens were from 12 patients who were subject to chromosome painting of Chromosomes 1, 2 and 4. Chromosomes 1, 2 and 4 were analyzed in ∼5000 cells, which is equivalent to the whole-genome analysis of almost 2000 cells. The frequency of chromosome translocation was higher than the number of DICs formed, both before and after CT scanning. The frequency of chromosome translocations tended to be higher, but not significantly higher, in patients with a treatment history compared with patients without such a history. However, in contrast to the results for DIC formation, the frequency of translocations detected before and after the CT scan did not differ significantly. Therefore, analysis of chromosome translocation may not be a suitable assay for detecting chromosome aberrations in cases of low-dose radiation exposure from a CT scan. A significant increase in the frequency of chromosome translocations was not likely to be detected due to the high baseline before the CT scan; the high and variable frequency of translocations was probably due to multiple confounding factors in adults. PMID:26874116

  12. Soluble OX40L favors tumor rejection in CT26 colon carcinoma model.

    PubMed

    Serebrovskaya, Ekaterina O; Yuzhakova, Diana V; Ryumina, Alina P; Druzhkova, Irina N; Sharonov, George V; Kotlobay, Alexey A; Zagaynova, Elena V; Lukyanov, Sergey A; Shirmanova, Marina V

    2016-08-01

    OX40 receptor-expressing regulatory T cells (Tregs) populate tumors and suppress a variety of immune cells, posing a major obstacle for cancer immunotherapy. Different ways to functionally inactivate Tregs by triggering OX40 receptor have been suggested, including anti-OX40 antibodies and Fc:OX40L fusion proteins. To investigate whether the soluble extracellular domain of OX40L (OX40Lexo) is sufficient to enhance antitumor immune response, we generated an OX40Lexo-expressing CT26 colon carcinoma cell line and studied its tumorigenicity in immunocompetent BALB/c and T cell deficient nu/nu mice. We found that soluble OX40L expressed in CT26 colon carcinoma favors the induction of an antitumor response which is not limited just to cells co-expressing EGFP as an antigenic determinant, but also eliminates CT26 cells expressing another fluorescent protein, KillerRed. Tumor rejection required the presence of T lymphocytes, as indicated by the unhampered tumor growth in nu/nu mice. Subsequent re-challenge of tumor-free BALB/c mice with CT26 EGFP cells resulted in no tumor growth, which is indicative of the formation of immunological memory. Adoptive transfer of splenocytes from mice that successfully rejected CT26 OX40Lexo EGFP tumors to naïve mice conferred 100% resistance to subsequent challenge with the CT26 EGFP tumor. PMID:27203665

  13. Variation compensation and analysis on diaphragm curvature analysis for emphysema quantification on whole lung CT scans

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Barr, R. Graham; Yankelevitz, David F.; Henschke, Claudia I.

    2010-03-01

    CT scans allow for the quantitative evaluation of the anatomical bases of emphysema. Recently, a non-density based geometric measurement of lung diagphragm curvature has been proposed as a method for the quantification of emphysema from CT. This work analyzes variability of diaphragm curvature and evaluates the effectiveness of a compensation methodology for the reduction of this variability as compared to emphysema index. Using a dataset of 43 scan-pairs with less than a 100 day time-interval between scans, we find that the diaphragm curvature had a trend towards lower overall variability over emphysema index (95% CI:-9.7 to + 14.7 vs. -15.8 to +12.0), and that the variation of both measures was reduced after compensation. We conclude that the variation of the new measure can be considered comparable to the established measure and the compensation can reduce the apparent variation of quantitative measures successfully.

  14. [Examination of motion artifacts for helical and non-helical scanning modes in head CT].

    PubMed

    Fujimura, Ichiro; Ichikawa, Katsuhiro; Terakawa, Shoichi; Hara, Takanori; Miura, Yohei

    2011-01-01

    For head computed tomography (CT), non-helical scanning has been recommended even in the widely used multi-slice CT (MSCT). Also, an acute stroke imaging standardization group has recommended the non-helical mode in Japan. However, no detailed comparison has been reported for current MSCT with more than 16 slices. In this study, we compared the non-helical and helical modes for head CT, focusing on temporal resolution and motion artifacts. The temporal resolution was evaluated by using temporal sensitivity profiles (TSPs) measured using a temporal impulse method. In both modes, the TSPs and temporal modulation transfer factors (MTFs) were measured for various pitch factors using 64-slice CT (Aquilion 64, Toshiba). Two motion phantoms were scanned to evaluate motion artifacts, and then quantitative analyses for motion artifacts and helical artifacts were performed by measuring multiple regions of interest (ROIs) in the phantom images. In addition, the rates of artifact occurrence for retrospective clinical cases were compared. The temporal resolution increased as the pitch factor was increased. Remarkable streak artifacts appeared in the non-helical images of the motion phantom, in spite of the equivalent effective temporal resolution. In clinical analysis, results consistent with the phantom studies were shown. These results indicated that the low pitch helical mode would be effective for emergency head CT with patient movement.

  15. 18F-Fluorodeoxyglucose Positron Emission Tomography/CT Scanning in Diagnosing Vascular Prosthetic Graft Infection

    PubMed Central

    Saleem, Ben R.; Pol, Robert A.; Slart, Riemer H. J. A.; Reijnen, Michel M. P. J.; Zeebregts, Clark J.

    2014-01-01

    Vascular prosthetic graft infection (VPGI) is a severe complication after vascular surgery. CT-scan is considered the diagnostic tool of choice in advanced VPGI. The incidence of a false-negative result using CT is relatively high, especially in the presence of low-grade infections. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) scanning has been suggested as an alternative for the diagnosis and assessment of infectious processes. Hybrid 18F-FDG PET/CT has established the role of 18F-FDG PET for the assessment of suspected VPGI, providing accurate anatomic localization of the site of infection. However, there are no clear guidelines for the interpretation of the uptake patterns of 18F-FDG as clinical tool for VPGI. Based on the available literature it is suggested that a linear, diffuse, and homogeneous uptake should not be regarded as an infection whereas focal or heterogeneous uptake with a projection over the vessel on CT is highly suggestive of infection. Nevertheless, 18F-FDG PET and 18F-FDG PET/CT can play an important role in the detection of VPGI and monitoring response to treatment. However an accurate uptake and pattern recognition is warranted and cut-off uptake values and patterns need to be standardized before considering the technique to be the new standard. PMID:25210712

  16. Automatic detection of axillary lymphadenopathy on CT scans of untreated chronic lymphocytic leukemia patients

    NASA Astrophysics Data System (ADS)

    Liu, Jiamin; Hua, Jeremy; Chellappa, Vivek; Petrick, Nicholas; Sahiner, Berkman; Farooqui, Mohammed; Marti, Gerald; Wiestner, Adrian; Summers, Ronald M.

    2012-03-01

    Patients with chronic lymphocytic leukemia (CLL) have an increased frequency of axillary lymphadenopathy. Pretreatment CT scans can be used to upstage patients at the time of presentation and post-treatment CT scans can reduce the number of complete responses. In the current clinical workflow, the detection and diagnosis of lymph nodes is usually performed manually by examining all slices of CT images, which can be time consuming and highly dependent on the observer's experience. A system for automatic lymph node detection and measurement is desired. We propose a computer aided detection (CAD) system for axillary lymph nodes on CT scans in CLL patients. The lung is first automatically segmented and the patient's body in lung region is extracted to set the search region for lymph nodes. Multi-scale Hessian based blob detection is then applied to detect potential lymph nodes within the search region. Next, the detected potential candidates are segmented by fast level set method. Finally, features are calculated from the segmented candidates and support vector machine (SVM) classification is utilized for false positive reduction. Two blobness features, Frangi's and Li's, are tested and their free-response receiver operating characteristic (FROC) curves are generated to assess system performance. We applied our detection system to 12 patients with 168 axillary lymph nodes measuring greater than 10 mm. All lymph nodes are manually labeled as ground truth. The system achieved sensitivities of 81% and 85% at 2 false positives per patient for Frangi's and Li's blobness, respectively.

  17. Computed Tomography (CT) Scanning Facilitates Early Identification of Neonatal Cystic Fibrosis Piglets

    PubMed Central

    Guillon, Antoine; Chevaleyre, Claire; Barc, Celine; Berri, Mustapha; Adriaensen, Hans; Lecompte, François; Villemagne, Thierry; Pezant, Jérémy; Delaunay, Rémi; Moënne-Loccoz, Joseph; Berthon, Patricia; Bähr, Andrea; Wolf, Eckhard; Klymiuk, Nikolai; Attucci, Sylvie; Ramphal, Reuben; Sarradin, Pierre; Buzoni-Gatel, Dominique; Si-Tahar, Mustapha; Caballero, Ignacio

    2015-01-01

    Background Cystic Fibrosis (CF) is the most prevalent autosomal recessive disease in the Caucasian population. A cystic fibrosis transmembrane conductance regulator knockout (CFTR-/-) pig that displays most of the features of the human CF disease has been recently developed. However, CFTR-/- pigs presents a 100% prevalence of meconium ileus that leads to death in the first hours after birth, requiring a rapid diagnosis and surgical intervention to relieve intestinal obstruction. Identification of CFTR-/- piglets is usually performed by PCR genotyping, a procedure that lasts between 4 to 6 h. Here, we aimed to develop a procedure for rapid identification of CFTR-/- piglets that will allow placing them under intensive care soon after birth and immediately proceeding with the surgical correction. Methods and Principal Findings Male and female CFTR+/- pigs were crossed and the progeny was examined by computed tomography (CT) scan to detect the presence of meconium ileus and facilitate a rapid post-natal surgical intervention. Genotype was confirmed by PCR. CT scan presented a 94.4% sensitivity to diagnose CFTR-/- piglets. Diagnosis by CT scan reduced the birth-to-surgery time from a minimum of 10 h down to a minimum of 2.5 h and increased the survival of CFTR-/- piglets to a maximum of 13 days post-surgery as opposed to just 66 h after later surgery. Conclusion CT scan imaging of meconium ileus is an accurate method for rapid identification of CFTR-/- piglets. Early CT detection of meconium ileus may help to extend the lifespan of CFTR-/- piglets and, thus, improve experimental research on CF, still an incurable disease. PMID:26600426

  18. Precision of cortical bone reconstruction based on 3D CT scans.

    PubMed

    Wang, Jianping; Ye, Ming; Liu, Zhongtang; Wang, Chengtao

    2009-04-01

    The precision and accuracy of human cortical bone reconstruction using 3D CT scans was evaluated using machined bone segments. Both linear and angular errors were measured. Cadaver adult femoral and tibial cortical bone segments were obtained and machined in six orthogonal planes with a precision milling machine. CT scans were then obtained and the bone segments were reconstructed as digital replicas. Dimensional and angular measurements errors were evaluated for the machined bone segments and the results were compared with known dimensions based on milling machine settings to calculate errors due to scanning and model reconstruction. The model dimensional error in the coronal, sagittal and axial directions had a mean of 0.21 mm, with standard a deviation of 0.12 mm and a maximum error of 0.47 mm. The mean percent error was 0.74% and the maximum percent error was 1.9%. The angular error of models in the coronal, sagittal and axial directions was calculated, yielding a mean of 0.47 degrees with a standard deviation of 0.37 degrees and a maximum of 1.33 degrees. The error in the cross-sectional axial direction had a mean of 0.54 mm with a maximum error of 0.83 mm, depending on the slice interval. The main error source was of the image processing, which was about 70% of the total error. We found that machining cortical bone segments prior to CT scanning is an effective method for accuracy evaluation of CT-based bone reconstruction. This method can provide a reference for assessing the sensitivity, reliability and accuracy of CT-based applications in the study of movement, finite element modeling, and prosthesis construction.

  19. Comparison of demons deformable registration-based methods for texture analysis of serial thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Cunliffe, Alexandra R.; Al-Hallaq, Hania A.; Fei, Xianhan M.; Tuohy, Rachel E.; Armato, Samuel G.

    2013-02-01

    To determine how 19 image texture features may be altered by three image registration methods, "normal" baseline and follow-up computed tomography (CT) scans from 27 patients were analyzed. Nineteen texture feature values were calculated in over 1,000 32x32-pixel regions of interest (ROIs) randomly placed in each baseline scan. All three methods used demons registration to map baseline scan ROIs to anatomically matched locations in the corresponding transformed follow-up scan. For the first method, the follow-up scan transformation was subsampled to achieve a voxel size identical to that of the baseline scan. For the second method, the follow-up scan was transformed through affine registration to achieve global alignment with the baseline scan. For the third method, the follow-up scan was directly deformed to the baseline scan using demons deformable registration. Feature values in matched ROIs were compared using Bland- Altman 95% limits of agreement. For each feature, the range spanned by the 95% limits was normalized to the mean feature value to obtain the normalized range of agreement, nRoA. Wilcoxon signed-rank tests were used to compare nRoA values across features for the three methods. Significance for individual tests was adjusted using the Bonferroni method. nRoA was significantly smaller for affine-registered scans than for the resampled scans (p=0.003), indicating lower feature value variability between baseline and follow-up scan ROIs using this method. For both of these methods, however, nRoA was significantly higher than when feature values were calculated directly on demons-deformed followup scans (p<0.001). Across features and methods, nRoA values remained below 26%.

  20. Evaluating the Influence of Wall-Roughness on Fracture Transmissivity with CT Scanning and Flow Simulations

    SciTech Connect

    Crandall, Dustin; Bromhal, Grant; McIntyre, Dustin

    2010-01-01

    Combining CT imaging of geomaterials with computational fluid dynamics provides substantial benefits to researchers. With simulations, geometric parameters can be varied in systematic ways that are not possible in the lab. This paper details the conversion of micro-CT images of a physical fracture in Berea sandstone to several tractable finite volume meshes. By computationally varying the level of detail captured from the scans we produced several realistic fracture geometries with different degrees of wall-roughness and various geometric properties. Simulations were performed and it was noted that increasing roughness increased the resistance to fluid flow. Also, as the distance between walls was increased the mean aperture approached the effective aperture.

  1. Raman and CT scan mapping of chalcogenide glass diffusion generated gradient index profiles

    NASA Astrophysics Data System (ADS)

    Lindberg, G. P.; Berg, R. H.; Deegan, J.; Benson, R.; Salvaggio, P. S.; Gross, N.; Weinstein, B. A.; Gibson, D.; Bayya, S.; Sanghera, J.; Nguyen, V.; Kotov, M.

    2016-05-01

    Metrology of a gradient index (GRIN) material is non-trivial, especially in the realm of infrared and large refractive index. Traditional methods rely on index matching fluids which are not available for indexes as high as those found in the chalcogenide glasses (2.4-3.2). By diffusing chalcogenide glasses of similar composition one can blend the properties in a continuous way. In an effort to measure this we will present data from both x-ray computed tomography scans (CT scans) and Raman mapping scans of the diffusion profiles. Proof of concept measurements on undiffused bonded sheets of chalcogenide glasses were presented previously. The profiles measured will be of axially stacked sheets of chalcogenide glasses diffused to create a linear GRIN profile and nested tubes of chalcogenide glasses diffused to create a radial parabolic GRIN profile. We will show that the x-ray absorption in the CT scan and the intensity of select Raman peaks spatially measured through the material are indicators of the concentration of the diffusion ions and correlate to the spatial change in refractive index. We will also present finite element modeling (FEM) results and compare them to post precision glass molded (PGM) elements that have undergone CT and Raman mapping.

  2. Efficient correction for CT image artifacts caused by objects extending outside the scan field of view.

    PubMed

    Ohnesorge, B; Flohr, T; Schwarz, K; Heiken, J P; Bae, K T

    2000-01-01

    The purpose of this paper is to develop a method of eliminating CT image artifacts generated by objects extending outside the scan field of view, such as obese or inadequately positioned patients. CT projection data are measured only within the scan field of view and thus are abruptly discontinuous at the projection boundaries if the scanned object extends outside the scan field of view. This data discontinuity causes an artifact that consists of a bright peripheral band that obscures objects near the boundary of the scan field of view. An adaptive mathematical extrapolation scheme with low computational expense was applied to reduce the data discontinuity prior to convolution in a filtered backprojection reconstruction. Despite extended projection length, the convolution length was not increased and thus the reconstruction time was not affected. Raw projection data from ten patients whose bodies extended beyond the scan field of view were reconstructed using a conventional method and our extended reconstruction method. Limitations of the algorithm are investigated and extensions for further improvement are discussed. The images reconstructed by conventional filtered backprojection demonstrated peripheral bright-band artifacts near the boundary of the scan field of view. Images reconstructed with our technique were free of such artifacts and clearly showed the anatomy at the periphery of the scan field of view with correct attenuation values. We conclude that bright-band artifacts generated by obese patients whose bodies extend beyond the scan field of view were eliminated with our reconstruction method, which reduces boundary data discontinuity. The algorithm can be generalized to objects with inhomogeneous peripheral density and to true "Region of Interest Reconstruction" from truncated projections.

  3. Three-dimensional volumetric display of CT data: effect of scan parameters upon image quality.

    PubMed

    Ney, D R; Fishman, E K; Magid, D; Robertson, D D; Kawashima, A

    1991-01-01

    Of the many steps involved in producing high quality three-dimensional (3D) images of CT data, the data acquisition step is of greatest consequence. The principle of "garbage in, garbage out" applies to 3D imaging--bad scanning technique produces equally bad 3D images. We present a formal study of the effect of two basic scanning parameters, slice thickness and slice spacing, on image quality. Three standard test objects were studied using variable CT scanning parameters. The objects chosen were a bone phantom, a cadaver femur with a simulated 5 mm fracture gap, and a cadaver femur with a simulated 1 mm fracture gap. Each object was scanned at three collimations: 8, 4, and 2 mm. For each collimation, four sets of scans were performed using four slice intervals: 8, 4, 3, and 2 mm. The bone phantom was scanned in two positions: oriented perpendicular to the scanning plane and oriented 45 degrees from the scanning plane. Three-dimensional images of the resulting 48 sets of data were produced using volumetric rendering. Blind review of the resultant 48 data sets was performed by three reviewers rating five factors for each image. The images resulting from scans with thin collimation and small table increments proved to rate the highest in all areas. The data obtained using 2 mm slice intervals proved to rate the highest in perceived image quality. Three millimeter slice spacing with 4 mm collimation, which clinically provides a good compromise between image quality and acquisition time and dose, also produced good perceived image quality. The studies with 8 mm slice intervals provided the least detail and introduced the worst inaccuracies and artifacts and were not suitable for clinical use. Statistical analysis demonstrated that slice interval (i.e., table incrementation) was of primary importance and slice collimation was of secondary, although significant, importance in determining perceived 3D image quality.

  4. Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration

    SciTech Connect

    Wolthaus, J. W. H.; Sonke, J.-J.; Herk, M. van; Damen, E. M. F.

    2008-09-15

    Purpose: lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. Methods and Materials: 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Results: Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods <0.5 mm for all directions) for the tumor region. From visual assessment, the registration was good

  5. CT scan

    MedlinePlus

    ... type of contrast given into a vein contains iodine. If you have an iodine allergy, a type of contrast may cause nausea ... steroids before the test. Your kidneys help remove iodine from the body. You may need to receive ...

  6. TU-F-18A-06: Dual Energy CT Using One Full Scan and a Second Scan with Very Few Projections

    SciTech Connect

    Wang, T; Zhu, L

    2014-06-15

    Purpose: The conventional dual energy CT (DECT) requires two full CT scans at different energy levels, resulting in dose increase as well as imaging errors from patient motion between the two scans. To shorten the scan time of DECT and thus overcome these drawbacks, we propose a new DECT algorithm using one full scan and a second scan with very few projections by preserving structural information. Methods: We first reconstruct a CT image on the full scan using a standard filtered-backprojection (FBP) algorithm. We then use a compressed sensing (CS) based iterative algorithm on the second scan for reconstruction from very few projections. The edges extracted from the first scan are used as weights in the Objectives: function of the CS-based reconstruction to substantially improve the image quality of CT reconstruction. The basis material images are then obtained by an iterative image-domain decomposition method and an electron density map is finally calculated. The proposed method is evaluated on phantoms. Results: On the Catphan 600 phantom, the CT reconstruction mean error using the proposed method on 20 and 5 projections are 4.76% and 5.02%, respectively. Compared with conventional iterative reconstruction, the proposed edge weighting preserves object structures and achieves a better spatial resolution. With basis materials of Iodine and Teflon, our method on 20 projections obtains similar quality of decomposed material images compared with FBP on a full scan and the mean error of electron density in the selected regions of interest is 0.29%. Conclusion: We propose an effective method for reducing projections and therefore scan time in DECT. We show that a full scan plus a 20-projection scan are sufficient to provide DECT images and electron density with similar quality compared with two full scans. Our future work includes more phantom studies to validate the performance of our method.

  7. Evolving Bioprosthetic Tissue Calcification Can Be Quantified Using Serial Multislice CT Scanning

    PubMed Central

    Meuris, B.; De Praetere, H.; Coudyzer, W.; Flameng, W.

    2013-01-01

    Background. We investigated the value of serial multislice CT scanning for in vivo determination of evolving tissue calcification in three separate experimental settings. Materials and Methods. Bioprosthetic valve tissue was implanted in three different conditions: (1) glutaraldehyde-fixed porcine stentless conduits in pulmonary position (n = 6); (2) glutaraldehyde-fixed stented pericardial valves in mitral position (n = 3); and (3) glutaraldehyde-fixed pericardial tissue as patch in the jugular vein and carotid artery (n = 16). Multislice CT scanning was performed at various time intervals. Results. In stentless conduits, the distribution of wall calcification can be reliably quantified with CT. After 20 weeks, the CT-determined mean calcium volume was 1831 ± 581 mm³, with a mean wall calcium content of 89.8 ± 44.4 μg/mg (r2 = 0.68). In stented pericardial valves implanted in mitral position, reliable determination of tissue mineralization is disturbed by scattering caused by the (continuously moving) alloy of the stent material. Pericardial patches in the neck vessels revealed progressive mineralization, with a significant increase in mean HU and calcium volume at 8 weeks after implantation, rising up to a level of 131.1 ± 39.6 mm³ (mean calcium volume score) and a mean calcium content of 19.1 ± 12.3 μg/mg. Conclusion. The process of bioprosthetic tissue mineralization can be visualized and quantified in vivo using multislice CT scanning. This allows determination of the kinetics of tissue mineralization with intermediate in vivo evaluations. PMID:24089616

  8. Intracranial myeloid metaplasia: diagnosis by CT and Fe52 scans and treatment by cranial irradiation

    SciTech Connect

    Cornfield, D.B.; Shipkin, P.; Alavi, A.; Becker, J.; Peyster, R.

    1983-11-01

    A patient with longstanding agnogenic myeloid metaplasia developed a progressive dementia. CT scanning demonstrated multiple intracranial masses, and a Fe/sub 52/ bone marrow scan demonstrated erythroid activity within the masses and confirmed the suspicion of extra-medullary hematopoiesis. A potentially hazardous biopsy was avoided, and a course of cranial irradiation was administered, resulting in regression of the masses and clearing of the patient's dementia. Fe/sub 52/ scintigraphy provides a specific and useful diagnostic approach which may eliminate the need for invasive procedures.

  9. Noise filtering in thin-slice 4D cerebral CT perfusion scans

    NASA Astrophysics Data System (ADS)

    Mendrik, Adri"nne; Vonken, Evert-jan; Dankbaar, Jan-Willem; Prokop, Mathias; van Ginneken, Bram

    2010-03-01

    Patients suffering from cerebral ischemia or subarachnoid hemorrhage, undergo a 4D (3D+time) CT Perfusion (CTP) scan to assess the cerebral perfusion and a CT Angiography (CTA) scan to assess the vasculature. The aim of our research is to extract the vascular information from the CTP scan. This requires thin-slice CTP scans that suffer from a substantial amount of noise. Therefore noise reduction is an important prerequisite for further analysis. So far, the few noise filtering methods for 4D datasets proposed in literature deal with the temporal dimension as a 4th dimension similar to the 3 spatial dimensions, mixing temporal and spatial intensity information. We propose a bilateral noise reduction method based on time-intensity profile similarity (TIPS), which reduces noise while preserving temporal intensity information. TIPS was compared to 4D bilateral filtering on 10 patient CTP scans and, even though TIPS bilateral filtering is much faster, it results in better vessel visibility and higher image quality ranking (observer study) than 4D bilateral filtering.

  10. Scanning electron microscope and micro-CT evaluation of cranial sutures in health and disease.

    PubMed

    Anderson, Peter J; Netherway, David J; David, David J; Self, Peter

    2006-09-01

    Current knowledge of suture biology has been ascertained as a result of morphological studies of normal cranial sutures (and rarely those undergoing craniosynostosis). These were initially undertaken often using histological investigations, or more recently using CT scans, as investigative tools, but have often used animal models. However, recent technological advances have provided the potential to refine our understanding of the ultrastructure by the use of new advanced scanning technology, which offers the possibility of more detailed resolution. Our aim was to undertake detailed scans of normal, fusing and fused sutures from patients with craniosynosotosis affecting different sutures, to study the detailed structure at different stages of the fusion process using a modern micro-CT scanner and a microanalytical scanning electron microscope. We wished to include in our study all the human sutures because previous studies have mostly been undertaken using the sagittal suture. Ten sutures from seven patients have revealed a complex ultra-structural arrangement. The different patterns of bone ridging seen on the ectocranial and endocranial surfaces of the fused sagittal suture were not repeated on closer inspection of either fused coronal or lambdoid sutures. Elemental analysis confirmed that the amount of calcium increased and the amount of carbon decreased as sampled areas moved away from the suture margin. We conclude that scanning allowed detailed assessment and revealed the complex arrangement of the structure of the human cranial sutures and those undergoing the process of craniosynostosis, with some differences in final structure depending on the affected suture.

  11. Association Between a Quantitative CT Scan Measure of Brain Edema and Outcome After Cardiac Arrest

    PubMed Central

    Metter, Robert B.; Rittenberger, Jon C.; Guyette, Francis X.; Callaway, Clifton W.

    2011-01-01

    Background Cerebral edema is one physical change associated with brain injury and decreased survival after cardiac arrest. Edema appears on computed tomography (CT) scan of the brain as decreased x-ray attenuation by gray matter. This study tested whether the gray matter attenuation to white matter attenuation ratio (GWR) was associated with survival and functional recovery. Methods Subjects were patients hospitalized after cardiac arrest at a single institution between 1/1/2005 and 7/30/2010. Subjects were included if they had non-traumatic cardiac arrest and a non-contrast CT scan within 24 hours after cardiac arrest. Attenuation (Hounsfield Units) was measured in gray matter (caudate nucleus, putamen, thalamus, and cortex) and in white matter (internal capsule, corpus callosum and centrum semiovale). The GWR was calculated for basal ganglia and cerebrum. Outcomes included survival and functional status at hospital discharge. Results For 680 patients, 258 CT scans were available, but 18 were excluded because of hemorrhage (10), intravenous contrast (3) or technical artifact (5), leaving 240 CT scans for analysis. Lower GWR values were associated with lower initial Glasgow Coma Scale motor score. Overall survival was 36%, but decreased with decreasing GWR. The average of basal ganglia and cerebrum GWR provided the best discrimination. Only 2/58 subjects with average GWR<1.20 survived and both were treated with hypothermia. The association of GWR with functional outcome was completely explained by mortality when GWR<1.20. Conclusions Subjects with severe cerebral edema, defined by GWR<1.20, have very low survival with conventional care, including hypothermia. GWR estimates pre-treatment likelihood of survival after cardiac arrest. PMID:21592642

  12. Small cell carcinoma of the brain without extracranial involvement by serial CT, MRI and PET.

    PubMed

    Terada, Tadashi

    2010-01-28

    The author reports herein a case of small cell carcinoma of the brain without extracranial tumors by serial imaging modalities. A 75-year-old man presented with headache. Brain CT and MRI revealed a solitary cystic tumor (5 x 6 x 7 cm) in the left occipital lobe. Blood laboratory test revealed no significant findings. Preoperative diagnosis was a primary or metastatic brain tumor. Preoperative systemic examinations including CT, MRI and PET revealed no extracranial tumors. Tumorectomy was performed. Pathologically, the tumor was small cell carcinoma positive for four types of pancytokeratins, cytokeratin (CK) 7, CK 18, thyroid transcriptional factor-1 (TTF-1), CD56, chromogranin, synaptophysin, neuron-specific enolase, p53 protein, KIT, PDGFRA, and Ki-67 antigen (labeling = 100%). It was negative for high molecular weight CK, CK5/6, CK14, CK19, CK20, PE10, epithelial membrane antigen, vimentin, CEA, desmin, S100 protein, CA19-9, alpha-smooth muscle actin, CD34, p63, and CD68. The pathologic examination strongly suggested primary small cell lung carcinoma. However, repeated serial imaging modalities including systemic CT, MRI and PET revealed no extracranial tumors. The serial sputum cytology was always negative. The patient was treated with radiation and cisplatin-based chemotherapy, and no tumors were found seven months after the operation. The present case suggests that there are small cell carcinomas with a solitary brain metastasis without a radiologically detected primary site. In the present case, primary small cell brain carcinoma cannot be excluded completely, although such a case has not been reported in the literature.

  13. Classification of pulmonary emphysema from chest CT scans using integral geometry descriptors

    NASA Astrophysics Data System (ADS)

    van Rikxoort, E. M.; Goldin, J. G.; Galperin-Aizenberg, M.; Brown, M. S.

    2011-03-01

    To gain insight into the underlying pathways of emphysema and monitor the effect of treatment, methods to quantify and phenotype the different types of emphysema from chest CT scans are of crucial importance. Current standard measures rely on density thresholds for individual voxels, which is influenced by inspiration level and does not take into account the spatial relationship between voxels. Measures based on texture analysis do take the interrelation between voxels into account and therefore might be useful for distinguishing different types of emphysema. In this study, we propose to use Minkowski functionals combined with rotation invariant Gaussian features to distinguish between healthy and emphysematous tissue and classify three different types of emphysema. Minkowski functionals characterize binary images in terms of geometry and topology. In 3D, four Minkowski functionals are defined. By varying the threshold and size of neighborhood around a voxel, a set of Minkowski functionals can be defined for each voxel. Ten chest CT scans with 1810 annotated regions were used to train the method. A set of 108 features was calculated for each training sample from which 10 features were selected to be most informative. A linear discriminant classifier was trained to classify each voxel in the lungs into a subtype of emphysema or normal lung. The method was applied to an independent test set of 30 chest CT scans with varying amounts and types of emphysema with 4347 annotated regions of interest. The method is shown to perform well, with an overall accuracy of 95%.

  14. Intermediate follow-up after endovascular aneurysm repair: can we forgo CT scanning in certain patients?

    PubMed

    Tomlinson, Jared; McNamara, Joanne; Matloubieh, Jubin; Hart, Joseph; Singh, Michael J; Davies, Mark G; Rhodes, Jeffrey M; Illig, Karl A

    2007-11-01

    Current recommendations for follow-up after endovascular repair of abdominal aortic aneurysms (EVAR) include yearly computed tomographic (CT) scans after the first year. We hypothesize that this is unnecessary for patients who have aneurysm sacs that are stable or shrinking at 1 year and no evidence of endoleak. To explore this hypothesis, we reviewed the records of all patients undergoing EVAR at our institution who were implanted with grafts that are currently commercially available and had a minimum of 18 months' follow-up. Of 415 patients who underwent EVAR over an 8-year period, 93 met the entry criteria. At a mean follow-up of approximately 3 years, secondary interventions were required in 13%, 39%, and 25% of patients undergoing EVAR with Zenith, AneuRx, and Excluder devices, respectively, and secondary interventions after the first year were required in 3%, 22%, and 8% of such grafts, respectively. Seventy-one patients (76%) had aneurysm sacs that were stable or shrinking at 1 year and no endoleak. Only two of these patients subsequently required reintervention. Both patients had AneuRx grafts, and both problems could have easily been identified without CT scanning. Our data support the hypothesis that patients who meet these criteria at 1 year are unlikely to have problems that cannot be identified by ultrasound and/or clinical evaluation alone and, thus, that CT scans are not necessary after this point, especially in patients with Zenith or reengineered Excluder devices. PMID:17980790

  15. Edge guided image reconstruction in linear scan CT by weighted alternating direction TV minimization.

    PubMed

    Cai, Ailong; Wang, Linyuan; Zhang, Hanming; Yan, Bin; Li, Lei; Xi, Xiaoqi; Li, Jianxin

    2014-01-01

    Linear scan computed tomography (CT) is a promising imaging configuration with high scanning efficiency while the data set is under-sampled and angularly limited for which high quality image reconstruction is challenging. In this work, an edge guided total variation minimization reconstruction (EGTVM) algorithm is developed in dealing with this problem. The proposed method is modeled on the combination of total variation (TV) regularization and iterative edge detection strategy. In the proposed method, the edge weights of intermediate reconstructions are incorporated into the TV objective function. The optimization is efficiently solved by applying alternating direction method of multipliers. A prudential and conservative edge detection strategy proposed in this paper can obtain the true edges while restricting the errors within an acceptable degree. Based on the comparison on both simulation studies and real CT data set reconstructions, EGTVM provides comparable or even better quality compared to the non-edge guided reconstruction and adaptive steepest descent-projection onto convex sets method. With the utilization of weighted alternating direction TV minimization and edge detection, EGTVM achieves fast and robust convergence and reconstructs high quality image when applied in linear scan CT with under-sampled data set.

  16. Assessment of outcomes with delayed 18F-FDG PET-CT response assessment in head and neck squamous cell carcinoma

    PubMed Central

    Slevin, F; Subesinghe, M; Ramasamy, S; Sen, M; Scarsbrook, A F

    2015-01-01

    Objective: To assess the accuracy of a 4-month post-(chemo)radiotherapy 18-fludeoxyglucose (18F-FDG) positron emission tomography (PET)-CT for head and neck squamous cell carcinoma (HNSCC). Methods: 105 patients who underwent a baseline and response assessment 18F-FDG PET-CT scan between 2008 and April 2013 were identified. 18F-FDG PET-CT outcomes were analysed with reference to clinicopathological outcomes. Results: 79 of 105 (75%) 18F-FDG PET-CT scans demonstrated a complete metabolic response; 19 of 101 (19%) for assessable primary tumours were positive; and 19 of 93 (20%) for patients with nodal disease were equivocal (n = 10) or positive (n = 9). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for primary and nodal disease were 90%, 89%, 47%, 99% and 91%, 89%, 53% and 99%, respectively. Eight of nine patients with a positive nodal response scan had clinicopathological evidence of residual nodal disease (PPV, 89%). 2 of 10 patients with equivocal nodal responses had clinicopathological evidence of residual nodal disease (PPV, 20%). Conclusion: 18F-FDG PET-CT 4 months post treatment has a very high NPV. A positive 18F-FDG PET-CT has a high PPV for residual nodal disease. By contrast, patients who have an equivocal nodal response have a low PPV. Advances in knowledge: Response assessment 18F-FDG PET-CT is a valuable tool in guiding the selective use of neck dissection following (chemo)radiotherapy for HNSCC. An equivocal lymph node response has a limited predictive value for persistent disease, and optimal management remains a clinical challenge. PMID:26081447

  17. Carotid plaque characterization using CT and MRI scans for synergistic image analysis

    NASA Astrophysics Data System (ADS)

    Getzin, Matthew; Xu, Yiqin; Rao, Arhant; Madi, Saaussan; Bahadur, Ali; Lennartz, Michelle R.; Wang, Ge

    2014-09-01

    Noninvasive determination of plaque vulnerability has been a holy grail of medical imaging. Despite advances in tomographic technologies , there is currently no effective way to identify vulnerable atherosclerotic plaques with high sensitivity and specificity. Computed tomography (CT) and magnetic resonance imaging (MRI) are widely used, but neither provides sufficient information of plaque properties. Thus, we are motivated to combine CT and MRI imaging to determine if the composite information can better reflect the histological determination of plaque vulnerability. Two human endarterectomy specimens (1 symptomatic carotid and 1 stable femoral) were imaged using Scanco Medical Viva CT40 and Bruker Pharmascan 16cm 7T Horizontal MRI / MRS systems. μCT scans were done at 55 kVp and tube current of 70 mA. Samples underwent RARE-VTR and MSME pulse sequences to measure T1, T2 values, and proton density. The specimens were processed for histology and scored for vulnerability using the American Heart Association criteria. Single modality-based analyses were performed through segmentation of key imaging biomarkers (i.e. calcification and lumen), image registration, measurement of fibrous capsule, and multi-component T1 and T2 decay modeling. Feature differences were analyzed between the unstable and stable controls, symptomatic carotid and femoral plaque, respectively. By building on the techniques used in this study, synergistic CT+MRI analysis may provide a promising solution for plaque characterization in vivo.

  18. Energy deposition in the breast during CT scanning: quantification and implications for dose reduction

    NASA Astrophysics Data System (ADS)

    Rupcich, Franco; Kyprianou, Iacovos; Badal, Andreu; Schmidt, Taly G.

    2011-03-01

    Studies suggest that dose to the breast leads to a higher lifetime attributable cancer incidence risk from a chest CT scan for women compared to men. Numerous methods have been proposed for reducing dose to the breast during CT scanning, including bismuth shielding, tube current modulation, partial-angular scanning, and reduced kVp. These methods differ in how they alter the spectrum and fluence across projection angle. This study used Monte Carlo CT simulations of a voxelized female phantom to investigate the energy (dose) deposition in the breast as a function of both photon energy and projection angle. The resulting dose deposition matrix was then used to investigate several questions regarding dose reduction to the breast: (1) Which photon energies deposit the most dose in the breast, (2) How does increased filtration compare to tube current reduction in reducing breast dose, and (3) Do reduced kVp scans reduce dose to breast, and if so, by what mechanism? The results demonstrate that while high-energy photons deposit more dose per emitted photon, the low-energy photons deposit more dose to the breast for a 120 kVp acquisition. The results also demonstrate that decreasing the tube current for the AP views to match the fluence exiting a shield deposits nearly the same dose to the breast as when using a shield (within ~1%). Finally, results suggest that the dose reduction observed during lower kVp scans is caused by reduced photon fluence rather than the elimination of high-energy photons from the beam. Overall, understanding the mechanisms of dose deposition in the breast as a function of photon energy and projection angle enables comparisons of dose reduction methods and facilitates further development of optimized dose reduction schemes.

  19. A CT scan protocol for the detection of radiographic loosening of the glenoid component after total shoulder arthroplasty

    PubMed Central

    2014-01-01

    Background and purpose It is difficult to evaluate glenoid component periprosthetic radiolucencies in total shoulder arthroplasties (TSAs) using plain radiographs. This study was performed to evaluate whether computed tomography (CT) using a specific patient position in the CT scanner provides a better method for assessing radiolucencies in TSA. Methods Following TSA, 11 patients were CT scanned in a lateral decubitus position with maximum forward flexion, which aligns the glenoid orientation with the axis of the CT scanner. Follow-up CT scanning is part of our routine patient care. Glenoid component periprosthetic lucency was assessed according to the Molé score and it was compared to routine plain radiographs by 5 observers. Results The protocol almost completely eliminated metal artifacts in the CT images and allowed accurate assessment of periprosthetic lucency of the glenoid fixation. Positioning of the patient within the CT scanner as described was possible for all 11 patients. A radiolucent line was identified in 54 of the 55 observed CT scans and osteolysis was identified in 25 observations. The average radiolucent line Molé score was 3.4 (SD 2.7) points with plain radiographs and 9.5 (SD 0.8) points with CT scans (p = 0.001). The mean intra-observer variance was lower in the CT scan group than in the plain radiograph group (p = 0.001). Interpretation The CT scan protocol we used is of clinical value in routine assessment of glenoid periprosthetic lucency after TSA. The technique improves the ability to detect and monitor radiolucent lines and, therefore, possibly implant loosening also. PMID:24286563

  20. Potential for Adult-Based Epidemiological Studies to Characterize Overall Cancer Risks Associated with a Lifetime of CT Scans

    PubMed Central

    Shuryak, Igor; Lubin, Jay H.; Brenner, David J.

    2014-01-01

    Recent epidemiological studies have suggested that radiation exposure from pediatric CT scanning is associated with small excess cancer risks. However, the majority of CT scans are performed on adults, and most radiation-induced cancers appear during middle or old age, in the same age range as background cancers. Consequently, a logical next step is to investigate the effects of CT scanning in adulthood on lifetime cancer risks by conducting adult-based, appropriately designed epidemiological studies. Here we estimate the sample size required for such studies to detect CT-associated risks. This was achieved by incorporating different age-, sex-, time- and cancer type-dependent models of radiation carcinogenesis into an in silico simulation of a population-based cohort study. This approach simulated individual histories of chest and abdominal CT exposures, deaths and cancer diagnoses. The resultant sample sizes suggest that epidemiological studies of realistically sized cohorts can detect excess lifetime cancer risks from adult CT exposures. For example, retrospective analysis of CT exposure and cancer incidence data from a population-based cohort of 0.4 to 1.3 million (depending on the carcinogenic model) CT-exposed UK adults, aged 25–65 in 1980 and followed until 2015, provides 80% power for detecting cancer risks from chest and abdominal CT scans. PMID:24828111

  1. [What are the tools for post-occupational follow-up, how should they be performed and what are their performance, limits and benefit/risk ratio? Chest X-Ray and CT scan].

    PubMed

    Ferretti, G

    2011-06-01

    Chest radiography and computed tomography (CT) are the two radiological techniques used for the follow-up of people exposed to asbestos. Since the last conference of consensus (1999), the scientific literature has primarily covered high-resolution CT and high-resolution volume CT (HR-VCT). We consider in turn the contribution of digital thoracic radiography, recommendations for the performance of HR-VCT to ensure the quality of examination while controlling the delivered radiation dose, and the need to refer to the "CT atlas of benign diseases related to asbestos exposure", published by a group of French experts in 2007, for interpretation. The results of the published studies concerning radiography or CT are then reviewed. We note the great interobserver variability in the recognition of pleural plaques and asbestosis, indicating the need for adequate training of radiologists, and the importance of defining standardized, quantified criteria for CT abnormalities. The very low agreement between thoracic and general radiologists must be taken into account. The reading of CT scans in cases of occupational exposure to asbestos should be entrusted to thoracic radiologists or to general radiologists having validated specific training. A double interpretation of CT could be considered in medicosocial requests. CT is more sensitive than chest radiography in the detection of bronchial carcinoma but generates a great number of false positive results (96 to 99%). No scientific data are available to assess the role of imaging by either CT or chest radiography in the early detection of mesothelioma.

  2. National Survey of Radiation Dose and Image Quality in Adult CT Head Scans in Taiwan

    PubMed Central

    Lin, Chung-Jung; Mok, Greta S. P.; Tsai, Mang-Fen; Tsai, Wei-Ta; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin

    2015-01-01

    Introduction The purpose of the present study was to evaluate the influence of different variables on radiation dose and image quality based on a national database. Materials and Methods Taiwan’s Ministry of Health and Welfare requested all radiology departments to complete a questionnaire for each of their CT scanners. Information gathered included all scanning parameters for CT head scans. For the present analysis, CT machines were divided into three subgroups: single slice CT (Group A); multi-detector CT (MDCT) with 2-64 slices (Group B); and MDCT with more than 64 slices (Group C). Correlations between computed tomography dose index (CTDI) and signal-to-noise ratio (SNR) with cumulated tube rotation number (CTW(n)) and cumulated tube rotation time (CTW(s)), and sub group analyses of CTDI and SNR across the three groups were performed. Results CTDI values demonstrated a weak correlation (r = 0.33) with CTW(n) in Group A. SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C. MDCT with higher slice numbers used more tube potential resulting in higher effective doses. There were both significantly lower CTDI and SNR values in helical mode than in axial mode in Group B, but not Group C. Conclusion CTW(n) and CTW(s) did not influence radiation output. Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices. PMID:26125549

  3. Diagnostic applications of simultaneously acquired dual-isotope single-photon emission CT scans

    SciTech Connect

    Mathews, D.; Walker, B.S.; Allen, B.C.; Batjer, H.; Purdy, P.D. )

    1994-01-01

    To report the development and validation of a technique of dual tracer single-photon emission CT brain imaging using technetium-99m hexamethyl-propyleneamine oxime and iodine-123 iodoamphetamine agents and the application of this technique in patients with a variety of diagnoses. Contamination between the two isotopes' energy windows was calculated by opening both energy windows while scanning a group of patients using a single isotope. To compare uniformity of I-123 down-scatter. Tc-99m studies were performed both before and after the administration of I-123 in five of 24 dual studies. The 24 patients studied with the dual-isotope technique were evaluated during acetazolamide testing, trial balloon occlusion, or embolization of an arteriovenous malformation. In a dual acquisition, average count contamination of an I-123 study by Tc-99m was less than 1% of the total I-123 counts, and contamination of a Tc-99m study by I-123 was approximately 12% of the total Tc-99m counts. Tc-99m studies performed both before and after the administration of I-123 demonstrated that contaminating counts do not adversely affect scan interpretation. Dual-tracer scans were completed in all 24 patients, 10 of whom showed changes after intervention. Dual-tracer single-photon emission CT brain scans of adequate diagnostic quality are possible using Tc-99m and I-123. 18 refs., 5 figs., 3 tabs.

  4. A new CT collimator for producing two simultaneous overlapping slices from one scan. [for biomedical applications

    NASA Technical Reports Server (NTRS)

    Kwoh, Y. S.; Glenn, W. V., Jr.; Reed, I. S.; Truong, T. K.

    1981-01-01

    A new CT collimator is developed which is capable of producing two simultaneous successive overlapping images from a single scan. The collimator represents a modification of the standard EMI 5005 collimator achieved by alternately masking one end or portions of both ends of the X-ray detectors at a 13-mm beamwidth so that a set of 540 filtered projections is obtained for each scan which can be separated into two sets of interleaved projections corresponding to views 3 mm apart. Tests have demonstrated that the quality of the images produced from these two projections almost equals the quality of those produced by the standard collimator from two separate scans. The new collimator may thus be used to achieve a speed improvement in the generation of overlapping sections as well as a reduction in X-ray dosage.

  5. The impact of CT scan energy on range calculation in proton therapy planning.

    PubMed

    Grantham, Kevin K; Li, Hua; Zhao, Tianyu; Klein, Eric E

    2015-01-01

    The purpose of this study was to investigate the impact of tube potential (kVp) on the CT number (HU) to proton stopping power ratio (PSPR) conversion. The range and dosimetric change introduced by a mismatch in kVp used for the CT scan and the HU to PSPR table, based on a specific kVp, used to calculate dose are analyzed. Three HU to PSPR curves, corresponding to three kVp settings on the CT scanner, were created. A treatment plan was created for a single beam in a water phantom passing through a wedge-shaped bone heterogeneity. The dose was recalculated by changing only the HU to PSPR table used in the dose calculation. The change in the position of the distal 90% isodose line was recorded as a function of heterogeneity thickness along the beam path. The dosimetric impact of a mismatch in kVp between the CT and the HU to PSPR table was investigated by repeating this procedure for five clinical plans comparing DVH data and dose difference distributions. The HU to PSPR tables diverge for CT numbers greater than 200 HU. In the phantom plan, the divergence of the tables resulted in a difference in range of 1.6 mm per cm of bone in the beam path, for the HU used. For the clinical plans, the dosimetric effect of a kVp mismatch depends on the amount of bone in the beam path and the proximity of OARs to the distal range of the planned beams. A mismatch in kVp between the CT and the HU to PSPR table can introduce inaccuracy in the proton beam range. For dense bone, the measured range difference was approximately 1.6 mm per cm of bone along the beam path. However, the clinical cases analyzed showed a range change of 1 mm or less. Caution is merited when such a mismatch may occur. PMID:26699561

  6. A Survey of Pediatric CT Protocols and Radiation Doses in South Korean Hospitals to Optimize the Radiation Dose for Pediatric CT Scanning

    PubMed Central

    Hwang, Jae-Yeon; Do, Kyung-Hyun; Yang, Dong Hyun; Cho, Young Ah; Yoon, Hye-Kyung; Lee, Jin Seong; Koo, Hyun Jung

    2015-01-01

    Abstract Children are at greater risk of radiation exposure than adults because the rapidly dividing cells of children tend to be more radiosensitive and they have a longer expected life time in which to develop potential radiation injury. Some studies have surveyed computed tomography (CT) radiation doses and several studies have established diagnostic reference levels according to patient age or body size; however, no survey of CT radiation doses with a large number of patients has yet been carried out in South Korea. The aim of the present study was to investigate the radiation dose in pediatric CT examinations performed throughout South Korea. From 512 CT (222 brain CT, 105 chest CT, and 185 abdominopelvic CT) scans that were referred to our tertiary hospital, a dose report sheet was available for retrospective analysis of CT scan protocols and dose, including the volumetric CT dose index (CTDIvol), dose-length product (DLP), effective dose, and size-specific dose estimates (SSDE). At 55.2%, multiphase CT was the most frequently performed protocol for abdominopelvic CT. Tube current modulation was applied most often in abdominopelvic CT and chest CT, accounting for 70.1% and 62.7%, respectively. Regarding the CT dose, the interquartile ranges of the CTDIvol were 11.1 to 22.5 (newborns), 16.6 to 39.1 (≤1 year), 14.6 to 41.7 (2–5 years), 23.5 to 44.1 (6–10 years), and 31.4 to 55.3 (≤15 years) for brain CT; 1.3 to 5.7 (≤1 year), 3.9 to 6.8 (2–5 years), 3.9 to 9.3 (6–10 years), and 7.7 to 13.8 (≤15 years) for chest CT; and 4.0 to 7.5 (≤1 year), 4.2 to 8.9 (2–5 years), 5.7 to 12.4 (6–10 years), and 7.6 to 16.6 (≤15 years) for abdominopelvic CT. The SSDE and CTDIvol were well correlated for patients <5 years old, whereas the CTDIvol was lower in patients ≥6 years old. Our study describes the various parameters and dosimetry metrics of pediatric CT in South Korea. The CTDIvol, DLP, and effective dose were generally lower than in German and UK

  7. Automatic classication of pulmonary function in COPD patients using trachea analysis in chest CT scans

    NASA Astrophysics Data System (ADS)

    van Rikxoort, E. M.; de Jong, P. A.; Mets, O. M.; van Ginneken, B.

    2012-03-01

    Chronic Obstructive Pulmonary Disease (COPD) is a chronic lung disease that is characterized by airflow limitation. COPD is clinically diagnosed and monitored using pulmonary function testing (PFT), which measures global inspiration and expiration capabilities of patients and is time-consuming and labor-intensive. It is becoming standard practice to obtain paired inspiration-expiration CT scans of COPD patients. Predicting the PFT results from the CT scans would alleviate the need for PFT testing. It is hypothesized that the change of the trachea during breathing might be an indicator of tracheomalacia in COPD patients and correlate with COPD severity. In this paper, we propose to automatically measure morphological changes in the trachea from paired inspiration and expiration CT scans and investigate the influence on COPD GOLD stage classification. The trachea is automatically segmented and the trachea shape is encoded using the lengths of rays cast from the center of gravity of the trachea. These features are used in a classifier, combined with emphysema scoring, to attempt to classify subjects into their COPD stage. A database of 187 subjects, well distributed over the COPD GOLD stages 0 through 4 was used for this study. The data was randomly divided into training and test set. Using the training scans, a nearest mean classifier was trained to classify the subjects into their correct GOLD stage using either emphysema score, tracheal shape features, or a combination. Combining the proposed trachea shape features with emphysema score, the classification performance into GOLD stages improved with 11% to 51%. In addition, an 80% accuracy was achieved in distinguishing healthy subjects from COPD patients.

  8. Analysis of calibration materials to improve dual-energy CT scanning for petrophysical applications

    SciTech Connect

    Ayyalasomavaiula, K.; McIntyre, D.; Jain, J.; Singh, J.; Yueh, F.

    2011-01-01

    Dual energy CT-scanning is a rapidly emerging imaging technique employed in non-destructive evaluation of various materials. Although CT (Computerized Tomography) has been used for characterizing rocks and visualizing and quantifying multiphase flow through rocks for over 25 years, most of the scanning is done at a voltage setting above 100 kV for taking advantage of the Compton scattering (CS) effect, which responds to density changes. Below 100 kV the photoelectric effect (PE) is dominant which responds to the effective atomic numbers (Zeff), which is directly related to the photo electric factor. Using the combination of the two effects helps in better characterization of reservoir rocks. The most common technique for dual energy CT-scanning relies on homogeneous calibration standards to produce the most accurate decoupled data. However, the use of calibration standards with impurities increases the probability of error in the reconstructed data and results in poor rock characterization. This work combines ICP-OES (inductively coupled plasma optical emission spectroscopy) and LIBS (laser induced breakdown spectroscopy) analytical techniques to quantify the type and level of impurities in a set of commercially purchased calibration standards used in dual-energy scanning. The Zeff data on the calibration standards with and without impurity data were calculated using the weighted linear combination of the various elements present and used in calculating Zeff using the dual energy technique. Results show 2 to 5% difference in predicted Zeff values which may affect the corresponding log calibrations. The effect that these techniques have on improving material identification data is discussed and analyzed. The workflow developed in this paper will translate to a more accurate material identification estimates for unknown samples and improve calibration of well logging tools.

  9. Male and Female Human Body Tissue Radiation Shielding Models Based upon CT-scan Data for Organ Dose Prediction

    NASA Astrophysics Data System (ADS)

    Qualls, G.; Nealy, J.; Wilson, J.; Cucinotta, F.

    As present and future human space mission lengths are extended, it becomes increasingly important and valuable to have accurate analytic predictions of radiation doses to specific tissues within the body. New computational models are being developed to help predict the effective radiation shielding to points inside the human body provided by the surrounding body tissue. A female body tissue model, based upon a full-body CT-scan from the Visible Human Project, is presented along with a male body tissue model based upon a full-body CT-scan data set obtained from Johns Hopkins University. The advantages of using CT-scan based models are presented along with initial results and comparisons to previous models. Details of the data processing required to transform a raw CT-scan into a tissue shielding model are also presented.

  10. In vitro dose measurements in a human cadaver with abdomen/pelvis CT scans

    PubMed Central

    Zhang, Da; Padole, Atul; Li, Xinhua; Singh, Sarabjeet; Khawaja, Ranish Deedar Ali; Lira, Diego; Liu, Tianyu; Shi, Jim Q.; Otrakji, Alexi; Kalra, Mannudeep K.; Xu, X. George; Liu, Bob

    2014-01-01

    Purpose: To present a study of radiation dose measurements with a human cadaver scanned on a clinical CT scanner. Methods: Multiple point dose measurements were obtained with high-accuracy Thimble ionization chambers placed inside the stomach, liver, paravertebral gutter, ascending colon, left kidney, and urinary bladder of a human cadaver (183 cm in height and 67.5 kg in weight) whose abdomen/pelvis region was scanned repeatedly with a multidetector row CT. The flat energy response and precision of the dosimeters were verified, and the slight differences in each dosimeter's response were evaluated and corrected to attain high accuracy. In addition, skin doses were measured for radiosensitive organs outside the scanned region with OSL dosimeters: the right eye, thyroid, both nipples, and the right testicle. Three scan protocols were used, which shared most scan parameters but had different kVp and mA settings: 120-kVp automA, 120-kVp 300 mA, and 100-kVp 300 mA. For each protocol three repeated scans were performed. Results: The tube starting angle (TSA) was found to randomly vary around two major conditions, which caused large fluctuations in the repeated point dose measurements: for the 120-kVp 300 mA protocol this angle changed from approximately 110° to 290°, and caused 8% − 25% difference in the point dose measured at the stomach, liver, colon, and urinary bladder. When the fluctuations of the TSA were small (within 5°), the maximum coefficient of variance was approximately 3.3%. The soft tissue absorbed doses averaged from four locations near the center of the scanned region were 27.2 ± 3.3 and 16.5 ± 2.7 mGy for the 120 and 100-kVp fixed-mA scans, respectively. These values were consistent with the corresponding size specific dose estimates within 4%. The comparison of the per-100-mAs tissue doses from the three protocols revealed that: (1) dose levels at nonsuperficial locations in the TCM scans could not be accurately deduced by simply scaling the

  11. In vitro dose measurements in a human cadaver with abdomen/pelvis CT scans

    SciTech Connect

    Zhang, Da; Padole, Atul; Li, Xinhua; Singh, Sarabjeet; Khawaja, Ranish Deedar Ali; Lira, Diego; Shi, Jim Q.; Otrakji, Alexi; Kalra, Mannudeep K.; Liu, Bob; Liu, Tianyu; Xu, X. George

    2014-09-15

    Purpose: To present a study of radiation dose measurements with a human cadaver scanned on a clinical CT scanner. Methods: Multiple point dose measurements were obtained with high-accuracy Thimble ionization chambers placed inside the stomach, liver, paravertebral gutter, ascending colon, left kidney, and urinary bladder of a human cadaver (183 cm in height and 67.5 kg in weight) whose abdomen/pelvis region was scanned repeatedly with a multidetector row CT. The flat energy response and precision of the dosimeters were verified, and the slight differences in each dosimeter's response were evaluated and corrected to attain high accuracy. In addition, skin doses were measured for radiosensitive organs outside the scanned region with OSL dosimeters: the right eye, thyroid, both nipples, and the right testicle. Three scan protocols were used, which shared most scan parameters but had different kVp and mA settings: 120-kVp automA, 120-kVp 300 mA, and 100-kVp 300 mA. For each protocol three repeated scans were performed. Results: The tube starting angle (TSA) was found to randomly vary around two major conditions, which caused large fluctuations in the repeated point dose measurements: for the 120-kVp 300 mA protocol this angle changed from approximately 110° to 290°, and caused 8% − 25% difference in the point dose measured at the stomach, liver, colon, and urinary bladder. When the fluctuations of the TSA were small (within 5°), the maximum coefficient of variance was approximately 3.3%. The soft tissue absorbed doses averaged from four locations near the center of the scanned region were 27.2 ± 3.3 and 16.5 ± 2.7 mGy for the 120 and 100-kVp fixed-mA scans, respectively. These values were consistent with the corresponding size specific dose estimates within 4%. The comparison of the per-100-mAs tissue doses from the three protocols revealed that: (1) dose levels at nonsuperficial locations in the TCM scans could not be accurately deduced by simply scaling the

  12. Cervical CT scan-guided epidural blood patches for spontaneous intracranial hypotension.

    PubMed

    Maingard, Julian; Giles, Lauren; Marriott, Mark; Phal, Pramit M

    2015-12-01

    We describe two patients with spontaneous intracranial hypotension (SIH), presenting with postural headache due to C1-C2 cerebrospinal fluid (CSF) leak. Both patients were refractory to lumbar epidural blood patching (EBP), and subsequently underwent successful CT scan-guided cervical EBP. SIH affects approximately 1 in 50,000 patients, with females more frequently affected. Its associated features are variable, and as such, misdiagnosis is common. Therefore, imaging plays an important role in the diagnostic workup of SIH and can include MRI of the brain and spine, CT myelogram, and radionuclide cisternography. In patients with an established diagnosis and confirmed CSF leak, symptoms will usually resolve with conservative management. However, in a select subgroup of patients, the symptoms are refractory to medical management and require more invasive therapies. In patients with cervical leaks, EBP in the cervical region is an effective management approach, either in close proximity to, or directly targeting a dural defect. CT scan-guided cervical EBP is an effective treatment approach in refractory SIH, and should be considered in those patients who are refractory to conservative management. PMID:26209918

  13. Cervical CT scan-guided epidural blood patches for spontaneous intracranial hypotension.

    PubMed

    Maingard, Julian; Giles, Lauren; Marriott, Mark; Phal, Pramit M

    2015-12-01

    We describe two patients with spontaneous intracranial hypotension (SIH), presenting with postural headache due to C1-C2 cerebrospinal fluid (CSF) leak. Both patients were refractory to lumbar epidural blood patching (EBP), and subsequently underwent successful CT scan-guided cervical EBP. SIH affects approximately 1 in 50,000 patients, with females more frequently affected. Its associated features are variable, and as such, misdiagnosis is common. Therefore, imaging plays an important role in the diagnostic workup of SIH and can include MRI of the brain and spine, CT myelogram, and radionuclide cisternography. In patients with an established diagnosis and confirmed CSF leak, symptoms will usually resolve with conservative management. However, in a select subgroup of patients, the symptoms are refractory to medical management and require more invasive therapies. In patients with cervical leaks, EBP in the cervical region is an effective management approach, either in close proximity to, or directly targeting a dural defect. CT scan-guided cervical EBP is an effective treatment approach in refractory SIH, and should be considered in those patients who are refractory to conservative management.

  14. Regarding the Credibility of Data Showing an Alleged Association of Cancer with Radiation from CT Scans.

    PubMed

    Socol, Yehoshua; Welsh, James S

    2016-02-01

    Computed tomography (CT) scans are of high clinical value as a diagnostic technique, and new applications continue to be identified. However, their application is challenged by emerging concerns regarding carcinogenesis from their radiation. Recent articles made a significant contribution to the above-mentioned concerns by reporting evidence for direct association of the radiation from CT scans with cancer. Such interpretation of the data has already been criticized; there is the possibility of reverse causation due to confounding factors. Nevertheless, such work has had a high impact, with one article being cited more than 300 times from the Web of Science Core Collection within 2 years. However, the data points on cancer relative risk versus CT dose in that article fit straight lines corresponding to the linear no-threshold hypothesis suspiciously well. Here, by applying rigorous statistical analysis, it is shown that the probability of the fit truly being that good or better is only 2%. The results of such studies therefore appear "too good to be true" and the credibility of their conclusions must be questioned.

  15. A Prospective Evaluation of Staging and Target Volume Definition of Lymph Nodes by {sup 18}FDG PET/CT in Patients With Squamous Cell Carcinoma of Thoracic Esophagus

    SciTech Connect

    Yu Wen; Fu Xiaolong; Zhang Yingjian; Xiang Jiaqing; Shen Lei; Chang, Joe Y.

    2011-12-01

    Purpose: To determine an optimal standardized uptake value (SUV) threshold for detecting lymph node (LN) metastases in esophageal cancer using {sup 18}F-Fluorodeoxyglucose positron emission tomography/computer tomography ({sup 18}FDG PET/CT) and to define the resulting nodal target volume, using histopathology as a 'gold standard.' Methods: Sixteen patients with esophageal squamous cell carcinoma who underwent radical esophagectomy and three-field LN dissection after {sup 18}FDG PET/CT and CT scans were enrolled into this study. Locations of LN groups were recorded according to a uniform LN map. Diagnostic performance of different SUV thresholds was assessed by receiver operating characteristic analysis. The optimal cutoff SUV was determined by plotting the false-negative rate (FNR) and false-positive rate (FPR), the sum of both error rates (FNR+FPR), and accuracy against a hypothetical SUV threshold. For each patient, nodal gross tumor volumes (GTVNs) were generated with CT alone (GTVNCT), PET/CT (GTVNPET), and pathologic data (GTVNpath). GTVNCT or GTVNPET was compared with GTVNpath by means of a conformity index (CI), which is the intersection of the two GTVNs divided by the sum of them minus the intersection, e.g., CI{sub CT} and {sub path} = GTVN{sub CT} and {sub path}/(GTVN{sub CT}+ GTVN{sub path} - GTVN{sub CT} and {sub path}). Results: LN metastases occurred in 21 LN groups among the 144 specimens taken from the 16 patients. The area under the receiver operating characteristic curve was 0.9017 {+-} 0.0410. The plot of error rates showed a minimum of FNR+FPR for an SUV of 2.36, at which the sensitivity, specificity, and accuracy were 76.19%, 95.93%, and 93.06%, respectively, whereas those of CT were 33.33%, 94.31%, and 85.42% (p values: 0.0117, 0.7539, and 0.0266). Mean GTVN{sub CT}, GTVN{sub PET}, and GTVN{sub path} were 1.52 {+-} 2.38, 2.82 {+-} 4.51, and 2.68 {+-} 4.16cm{sup 3}, respectively. Mean CI{sub CT} and {sub path} and CI{sub PET} and {sub path

  16. Change of SUVmax Slope in Dynamic Triphasic FDG-PET/CT Distinguishes Malignancy from Post-Radiation Inflammation in Head and Neck Squamous Cell Carcinoma - a Prospective Trial

    PubMed Central

    Anderson, Carryn M; Chang, Tangel; Graham, Michael; Marquardt, Michael D; Button, Anna; Smith, Brian J; Menda, Yusuf; Sun, Wenqing; Pagedar, Nitin A; Buatti, John

    2014-01-01

    Purpose/Objectives(s) The positive predictive value (PPV) of post-radiation (RT) 3-month FDG-PET/CT imaging in head and neck squamous cell carcinoma (HNSCC) is limited. Dynamic data acquisition and analysis was evaluated for PPV improvement, utilizing a triphasic PET/CT technique. Methods and Materials We prospectively enrolled HNSCC patients who completed RT, with scheduled 3-month post-RT FDG-PET/CT. Patients underwent our standard whole-body PET/CT scan at 90 minutes, with the addition of head and neck PET/CTs at 60 and 120 minutes. Maximum standardized uptake values (SUVmax) of regions of interest (ROI) were measured at 60, 90, and 120 minutes. SUVmax slope between 60 and 120 minutes, and change of SUVmax slope before and after 90 minutes were calculated. Data were analyzed by primary site and nodal site disease status using the Cox regression model and Wilcoxon Rank Sum Test. Outcomes were based on pathologic and clinical follow-up. Results 84 patients enrolled, with 79 primary and 43 nodal evaluable sites. Twenty-eight sites were interpreted positive or equivocal (18 primary, 8 nodal, 2 distant) on 3-month 90-minute FDG-PET/CT. Median follow-up was 13.3 months. All measured SUV endpoints predicted recurrence. Change of SUVmax slope after 90 minutes more accurately identified non-recurrence in positive or equivocal sites than our current standard of SUVmax ≥ 2.5 (p=0.02). Conclusions The PPV of post-RT FDG-PET/CT may significantly improve using novel second derivative analysis of dynamic triphasic FDG-PET/CT SUVmax slope, accurately distinguishing tumor from inflammation on positive and equivocal scans. PMID:25680593

  17. xCT expression modulates cisplatin resistance in Tca8113 tongue carcinoma cells

    PubMed Central

    ZHANG, PENG; WANG, WEI; WEI, ZHENHUI; XU, LI; YANG, XUANNING; DU, YUANHONG

    2016-01-01

    Tongue squamous cell carcinoma (TSCC), which is a subtype of head and neck cancer, is the most common type of oral cancer. Due to its high recurrence rate and chemoresistance, the average survival rate for patients with TSCC remains unsatisfactory. At present, cisplatin (CDDP) is utilized as the first-line treatment for numerous solid neoplasms, including TSCC. CDDP resistance develops in the majority of patients; however, the mechanism of such resistance remains unknown. Therefore, the present study aimed to clarify the mechanism of CDDP resistance and attempted to reduce chemoresistance. The results indicated that CDDP significantly increased expression of xCT, which is the light chain and functional subunit of the glutamate/cysteine transporter system xc−, and a subsequent increase in glutathione (GSH) levels was observed. The present study demonstrated that the upregulation of xCT expression and intercellular GSH levels contributed to CDDP resistance in TSCC cells. Furthermore, xCT suppression, induced by small interfering RNA or pharmacological inhibitors, sensitized TSCC cells to CDDP treatment. In conclusion, the present study revealed that CDDP-induced xCT expression promotes CDDP chemoresistance, and xCT inhibition sensitizes TSCC cells to CDDP treatment. These results provide a novel insight into the molecular mechanisms involved in TSCC cell chemoresistance. PMID:27347143

  18. Recent Advances in CT and MR Imaging for Evaluation of Hepatocellular Carcinoma

    PubMed Central

    Lee, Jeong Min; Yoon, Jeong-Hee; Joo, Ijin; Woo, Hyun Sik

    2012-01-01

    Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Accurate diagnosis and assessment of disease extent are crucial for proper management of patients with HCC. Imaging plays a crucial role in early detection, accurate staging, and the planning of management strategies. A variety of imaging modalities are currently used in evaluating patients with suspected HCC; these include ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and angiography. Among these modalities, dynamic MRI and CT are regarded as the best imaging techniques available for the noninvasive diagnosis of HCC. Recent improvements in CT and MRI technology have made noninvasive and reliable diagnostic assessment of hepatocellular nodules possible in the cirrhotic liver, and biopsy is frequently not required prior to treatment. Until now, the major challenge for radiologists in imaging cirrhosis has been the characterization of small cirrhotic nodules smaller than 2 cm in diameter. Further technological advancement will undoubtedly have a major impact on liver tumor imaging. The increased speed of data acquisition in CT and MRI has allowed improvements in both spatial and temporal resolution, which have made possible a more precise evaluation of the hemodynamics of liver nodules. Furthermore, the development of new, tissue-specific contrast agents such as gadoxetic acid has improved HCC detection on MRI. In this review, we discuss the role of CT and MRI in the diagnosis and staging of HCC, recent technological advances, and the strengths and limitations of these imaging modalities. PMID:24159569

  19. Cerebral blood flow and brain atrophy correlated by xenon contrast CT scanning

    SciTech Connect

    Kitagawa, Y.; Meyer, J.S.; Tanahashi, N.; Rogers, R.L.; Tachibana, H.; Kandula, P.; Dowell, R.E.; Mortel, K.F.

    1985-11-01

    Correlations between cerebral blood flow (CBF) measured during stable xenon contrast CT scanning and standard CT indices of brain atrophy were investigated in the patients with senile dementia of Alzheimer type, multi-infarct dementia and idiopathic Parkinson's disease. Compared to age-matched normal volunteers, significant correlations were found in patients with idiopathic Parkinson's disease between cortical and subcortical gray matter blood flow and brain atrophy estimated by the ventricular body ratio, and mild to moderate brain atrophy were correlated with stepwise CBF reductions. However, in patients with senile dementia of Alzheimer type and multi-infarct dementia, brain atrophy was not associated with stepwise CBF reductions. Overall correlations between brain atrophy and reduced CBF were weak. Mild degrees of brain atrophy are not always associated with reduced CBF.

  20. Scanning multiple samples simultaneously in tube-based microCT systems

    NASA Astrophysics Data System (ADS)

    Stock, S. R.; Rajamannan, N. M.; Spelsberg, T. C.; Malayannan, S.; Riaz, R.; Polavarapu, M.; Hsu, E. L.; Hsu, W., K.; Chen, Yan; Zhang, Ming

    2010-09-01

    The world-wide explosion of commercial microComputed Tomography (microCT) system emplacement has led to dayin, day-out access to laboratory scanners. Most biologically-oriented microCT facilities must characterize large numbers of samples rapidly at moderate spatial resolution (e.g., 10-20 μm isotropic volume elements, voxels). Scanning multiple specimens simultaneously is one efficient solution. Sample positioning is critical if the region of interest of each specimen is to be imaged without increasing the number of slices recorded (i.e., data acquisition and reconstruction times). Three very different, multiple sample data acquisitions are reported: mouse heart tissue calcification, rat spinal fusion and mouse tibial bone cancer models

  1. Semi-automated method to measure pneumonia severity in mice through computed tomography (CT) scan analysis

    NASA Astrophysics Data System (ADS)

    Johri, Ansh; Schimel, Daniel; Noguchi, Audrey; Hsu, Lewis L.

    2010-03-01

    Imaging is a crucial clinical tool for diagnosis and assessment of pneumonia, but quantitative methods are lacking. Micro-computed tomography (micro CT), designed for lab animals, provides opportunities for non-invasive radiographic endpoints for pneumonia studies. HYPOTHESIS: In vivo micro CT scans of mice with early bacterial pneumonia can be scored quantitatively by semiautomated imaging methods, with good reproducibility and correlation with bacterial dose inoculated, pneumonia survival outcome, and radiologists' scores. METHODS: Healthy mice had intratracheal inoculation of E. coli bacteria (n=24) or saline control (n=11). In vivo micro CT scans were performed 24 hours later with microCAT II (Siemens). Two independent radiologists scored the extent of airspace abnormality, on a scale of 0 (normal) to 24 (completely abnormal). Using the Amira 5.2 software (Mercury Computer Systems), a histogram distribution of voxel counts between the Hounsfield range of -510 to 0 was created and analyzed, and a segmentation procedure was devised. RESULTS: A t-test was performed to determine whether there was a significant difference in the mean voxel value of each mouse in the three experimental groups: Saline Survivors, Pneumonia Survivors, and Pneumonia Non-survivors. It was found that the voxel count method was able to statistically tell apart the Saline Survivors from the Pneumonia Survivors, the Saline Survivors from the Pneumonia Non-survivors, but not the Pneumonia Survivors vs. Pneumonia Non-survivors. The segmentation method, however, was successfully able to distinguish the two Pneumonia groups. CONCLUSION: We have pilot-tested an evaluation of early pneumonia in mice using micro CT and a semi-automated method for lung segmentation and scoring system. Statistical analysis indicates that the system is reliable and merits further evaluation.

  2. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-01

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  3. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.

    PubMed

    Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

    2014-09-21

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

  4. Clinical Utility of 4D FDG-PET/CT Scans in Radiation Treatment Planning

    SciTech Connect

    Aristophanous, Michalis; Sher, David J.; Allen, Aaron M.; Larson, Elysia; Chen, Aileen B.

    2012-01-01

    Purpose: The potential role of four-dimensional (4D) positron emission tomography (PET)/computed tomography (CT) in radiation treatment planning, relative to standard three-dimensional (3D) PET/CT, was examined. Methods and Materials: Ten patients with non-small-cell lung cancer had sequential 3D and 4D [{sup 18}F]fluorodeoxyglucose PET/CT scans in the treatment position prior to radiation therapy. The gross tumor volume and involved lymph nodes were contoured on the PET scan by use of three different techniques: manual contouring by an experienced radiation oncologist using a predetermined protocol; a technique with a constant threshold of standardized uptake value (SUV) greater than 2.5; and an automatic segmentation technique. For each technique, the tumor volume was defined on the 3D scan (VOL3D) and on the 4D scan (VOL4D) by combining the volume defined on each of the five breathing phases individually. The range of tumor motion and the location of each lesion were also recorded, and their influence on the differences observed between VOL3D and VOL4D was investigated. Results: We identified and analyzed 22 distinct lesions, including 9 primary tumors and 13 mediastinal lymph nodes. Mean VOL4D was larger than mean VOL3D with all three techniques, and the difference was statistically significant (p < 0.01). The range of tumor motion and the location of the tumor affected the magnitude of the difference. For one case, all three tumor definition techniques identified volume of moderate uptake of approximately 1 mL in the hilar region on the 4D scan (SUV maximum, 3.3) but not on the 3D scan (SUV maximum, 2.3). Conclusions: In comparison to 3D PET, 4D PET may better define the full physiologic extent of moving tumors and improve radiation treatment planning for lung tumors. In addition, reduction of blurring from free-breathing images may reveal additional information regarding regional disease.

  5. Advantages of Combined PET-CT in Mediastinal Staging in Patients with Non-small Cell Lung Carcinoma

    PubMed Central

    Beslic, Nermina; Sadija, Amera; Milardovic, Renata; Ceric, Timur; Ceric, Sejla; Beganovic, Adnan; Kristic, Spomenka; Cavaljuga, Semra

    2016-01-01

    Introduction: Precise mediastinal lymph node staging in patients with non-small cell lung carcinoma (NSCLC) provides important prognostic information and it is obligatory in treatment strategy planning. 18Fluoro-deoxy-glucose (18F-FDG) positron emission tomography - computerized tomography (PET-CT) based on detection of metabolic activity showed superiority in preoperative staging of lung carcinoma. Materials and Methods: Total number of 26 patients diagnosed with NSCLC were included in this retrospective, cross-sectional study. Status of mediastinal lymph nodes was assessed in all patients comparing contrast enhanced CT and 18F-FDG PET-CT findings. Discussion: We found in our study that 50% of patients had different N stage on contrast enhanced CT comparing to 18F-FDG PET-CT findings. Among the total number of patients which had different nodal status on PET-CT comparing to CT alone, we found in our study that 54% of patients had change in further therapy protocol after PET-CT change of nodal stage. Conclusion: Combined PET-CT which offers advantages of both modalities is excellent method for nodal (N) staging, so it is recommended in initial staging in patients with NSCLC. PET-CT used preopratively for mediastinal nodal staging has significant impact on further therapy planning and also has an consequential impact on health system savings. PMID:27147799

  6. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  7. The pros and cons of intraoperative CT scan in evaluation of deep brain stimulation lead implantation: A retrospective study

    PubMed Central

    Servello, Domenico; Zekaj, Edvin; Saleh, Christian; Pacchetti, Claudio; Porta, Mauro

    2016-01-01

    Background: Deep brain stimulation (DBS) is an established therapy for movement disorders, such as Parkinson's disease (PD), dystonia, and tremor. The efficacy of DBS depends on the correct lead positioning. The commonly adopted postoperative radiological evaluation is performed with computed tomography (CT) scan and/or magnetic resonance imaging (MRI). Methods: We conducted a retrospective study on 202 patients who underwent DBS from January 2009 to October 2013. DBS indications were PD, progressive supranuclear palsy, tremor, dystonia, Tourette syndrome, obsessive compulsive disorder, depression, and Huntington's disease. Preoperatively, all patients underwent brain MRI and brain CT scan with the stereotactic frame positioned. The lead location was confirmed intraoperatively with CT. The CT images were subsequently transferred to the Stealth Station Medtronic and merged with the preoperative planning. On the first or second day after, implantation we performed a brain MRI to confirm the correct position of the lead. Results: In 14 patients, leads were in suboptimal position after intraoperative CT scan positioning. The cases with alteration in the Z-axis were corrected immediately under fluoroscopic guidance. In all the 14 patients, an immediate repositioning was done. Conclusions: Based on our data, intraoperative CT scan is fast, safe, and a useful tool in the evaluation of the position of the implanted lead. It also reduces the patient's discomfort derived from the transfer of the patient from the operating room to the radiological department. However, intraoperative CT should not be considered as a substitute for postoperative MRI. PMID:27583182

  8. A novel reconstruction algorithm to extend the CT scan field-of-view.

    PubMed

    Hsieh, J; Chao, E; Thibault, J; Grekowicz, B; Horst, A; McOlash, S; Myers, T J

    2004-09-01

    For various reasons, a projection dataset acquired on a computed tomography (CT) scanner can be truncated. That is, a portion of the scanned object is positioned outside the scan field-of-view (SFOV) and the line integrals corresponding to those regions are not measured. A projection truncation problem causes imaging artifacts that lead to suboptimal image quality. In this paper, we propose a reconstruction algorithm that enables an adequate estimation of the projection outside the SFOV. We make use of the fact that the total attenuation of each ideal projection in a parallel sampling geometry remains constant over views. We use the magnitudes and slopes of the projection samples at the location of truncation to estimate water cylinders that can best fit to the projection data outside the SFOV. To improve the robustness of the algorithm, continuity constraints are placed on the fitting parameters. Extensive phantom and patient experiments were conducted to test the robustness and accuracy of the proposed algorithm.

  9. Extracting Information From Previous Full-Dose CT Scan for Knowledge-Based Bayesian Reconstruction of Current Low-Dose CT Images.

    PubMed

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

    2016-03-01

    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.

  10. Sensitivity calibration procedures in optical-CT scanning of BANG 3 polymer gel dosimeters

    SciTech Connect

    Xu, Y.; Wuu, Cheng-Shie; Maryanski, Marek J.

    2010-02-15

    The dose response of the BANG 3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurements on the 18 glass vials irradiated with graded doses from 0 to 4 Gy using 6 or 10 MV large field irradiations; (b) optical-CT scanning of Barex cylinders irradiated with graded doses (0.5, 1, 1.5, and 2 Gy) from four adjacent 4x4 cm{sup 2} photon fields or 6x6 cm{sup 2} electron fields; and (c) percent depth dose (PDD) comparison of optical-CT scans with ion chamber measurements for 6x6 cm{sup 2}, 12 and 16 MeV electron fields. The dose response of the BANG 3 gel was found to be linear and energy independent within the uncertainties of the experimental methods (about 3%). The slopes of the linearly fitted dose response curves (dose sensitivities) from the four field irradiations (0.0752{+-}3%, 0.0756{+-}3%, 0.0767{+-}3%, and 0.0759{+-}3% cm{sup -1} Gy{sup -1}) and the PDD matching methods (0.0768{+-}3% and 0.0761{+-}3% cm{sup -1} Gy{sup -1}) agree within 2.2%, indicating a good reproducibility of the gel dose response within phantoms of the same geometry. The dose sensitivities from the glass vial approach are different from those of the cylindrical Barex phantoms by more than 30%, owing probably to the difference in temperature inside the two types of phantoms during gel formation and irradiation, and possible oxygen contamination of the glass vial walls. The dose response curve obtained from the PDD matching approach with 16 MeV electron field was used to calibrate the gel phantom irradiated with the 12 MeV, 6x6 cm{sup 2} electron field. Three-dimensional dose distributions

  11. Sensitivity calibration procedures in optical-CT scanning of BANG®3 polymer gel dosimeters

    PubMed Central

    Xu, Y.; Wuu, Cheng-Shie; Maryanski, Marek J.

    2010-01-01

    The dose response of the BANG®3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS™ laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurements on the 18 glass vials irradiated with graded doses from 0 to 4 Gy using 6 or 10 MV large field irradiations; (b) optical-CT scanning of Barex cylinders irradiated with graded doses (0.5, 1, 1.5, and 2 Gy) from four adjacent 4×4 cm2 photon fields or 6×6 cm2 electron fields; and (c) percent depth dose (PDD) comparison of optical-CT scans with ion chamber measurements for 6×6 cm2, 12 and 16 MeV electron fields. The dose response of the BANG®3 gel was found to be linear and energy independent within the uncertainties of the experimental methods (about 3%). The slopes of the linearly fitted dose response curves (dose sensitivities) from the four field irradiations (0.0752±3%, 0.0756±3%, 0.0767±3%, and 0.0759±3% cm−1 Gy−1) and the PDD matching methods (0.0768±3% and 0.0761±3% cm−1 Gy−1) agree within 2.2%, indicating a good reproducibility of the gel dose response within phantoms of the same geometry. The dose sensitivities from the glass vial approach are different from those of the cylindrical Barex phantoms by more than 30%, owing probably to the difference in temperature inside the two types of phantoms during gel formation and irradiation, and possible oxygen contamination of the glass vial walls. The dose response curve obtained from the PDD matching approach with 16 MeV electron field was used to calibrate the gel phantom irradiated with the 12 MeV, 6×6 cm2 electron field. Three-dimensional dose distributions from the gel measurement and the Eclipse

  12. The relationship of pineal calcification to cerebral atrophy on CT scan in multiple sclerosis.

    PubMed

    Sandyk, R; Awerbuch, G I

    1994-05-01

    Calcification is a known morphological feature of the pineal gland. The mechanisms underlying the development of pineal calcification (PC) are elusive although there is experimental evidence that calcification may be a marker of the past secretory activity of the gland and/or of degeneration. The increased incidence of PC with aging suggests that it may reflect cerebral degenerative changes as well. In a recent Editorial in this Journal it was proposed that the pineal gland is implicated in the pathogenesis of multiple sclerosis (MS). Cerebral atrophy, which can be demonstrated on CT scan, is a common feature of MS resulting from demyelination and gliosis. If PC is a marker of a cerebral degenerative process, then one would expect a higher incidence of calcification of the gland in patients with cerebral atrophy compared to those without cerebral atrophy. To test this hypothesis, we studied the incidence of PC on CT scan in a cohort of 48 MS patients, 21 of whom had cerebral atrophy. For the purpose of comparison, we also assessed the incidence of choroid plexus calcification (CPC) in relation to cerebral atrophy. PC was found in 42 patients (87.5%) and its incidence in patients with cerebral atrophy was significantly higher compared to the incidence in patients without cerebral atrophy (100% vs. 77.7%; p < .025). In contrast, CPC was unrelated to cerebral atrophy or to PC thus supporting the notion of a specific association between the pineal gland and the pathogenesis of MS.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7960471

  13. Use of CT scanning to optimise the localisation procedure for breast radiotherapy.

    PubMed

    Rattray, G

    1989-07-01

    The continually improving technology in breast screening is now allowing diagnosis of patients with early stage breast cancer who would otherwise not have presented for many years. Surgical techniques are directed to achieving the best possible cosmetic result following the surgery. Radiotherapy treatment machines are becoming more complex and sophisticated in design and capability. Why, therefore, should we not employ today's technology for the localisation process? This is a report of our experience in using CT scanning to localise the treatment volumes for breast patients over a period of one year. A comparison between marking patients by palpation and the use of CT scanning has prevented a number of patients being under-treated and has enabled the reduction of lung volume included in the treatment volume for other patients. It has also proved a valuable aid in the decision to use electron fields for mastectomy patients. Other means of localising the treatment volumes are considered in the light of our experiences. PMID:2590443

  14. Evaluating 3D registration of CT-scan images using crest lines

    NASA Astrophysics Data System (ADS)

    Ayache, Nicholas; Gueziec, Andre P.; Thirion, Jean-Philippe; Gourdon, A.; Knoplioch, Jerome

    1993-06-01

    We consider the issue of matching 3D objects extracted from medical images. We show that crest lines computed on the object surfaces correspond to meaningful anatomical features, and that they are stable with respect to rigid transformations. We present the current chain of algorithmic modules which automatically extract the major crest lines in 3D CT-Scan images, and then use differential invariants on these lines to register together the 3D images with a high precision. The extraction of the crest lines is done by computing up to third order derivatives of the image intensity function with appropriate 3D filtering of the volumetric images, and by the 'marching lines' algorithm. The recovered lines are then approximated by splines curves, to compute at each point a number of differential invariants. Matching is finally performed by a new geometric hashing method. The whole chain is now completely automatic, and provides extremely robust and accurate results, even in the presence of severe occlusions. In this paper, we briefly describe the whole chain of processes, already presented to evaluate the accuracy of the approach on a couple of CT-scan images of a skull containing external markers.

  15. Angiogenesis in tissue-engineered nerves evaluated objectively using MICROFIL perfusion and micro-CT scanning

    PubMed Central

    Wang, Hong-kui; Wang, Ya-xian; Xue, Cheng-bin; Li, Zhen-mei-yu; Huang, Jing; Zhao, Ya-hong; Yang, Yu-min; Gu, Xiao-song

    2016-01-01

    Angiogenesis is a key process in regenerative medicine generally, as well as in the specific field of nerve regeneration. However, no convenient and objective method for evaluating the angiogenesis of tissue-engineered nerves has been reported. In this study, tissue-engineered nerves were constructed in vitro using Schwann cells differentiated from rat skin-derived precursors as supporting cells and chitosan nerve conduits combined with silk fibroin fibers as scaffolds to bridge 10-mm sciatic nerve defects in rats. Four weeks after surgery, three-dimensional blood vessel reconstructions were made through MICROFIL perfusion and micro-CT scanning, and parameter analysis of the tissue-engineered nerves was performed. New blood vessels grew into the tissue-engineered nerves from three main directions: the proximal end, the distal end, and the middle. The parameter analysis of the three-dimensional blood vessel images yielded several parameters, including the number, diameter, connection, and spatial distribution of blood vessels. The new blood vessels were mainly capillaries and microvessels, with diameters ranging from 9 to 301 μm. The blood vessels with diameters from 27 to 155 μm accounted for 82.84% of the new vessels. The microvessels in the tissue-engineered nerves implanted in vivo were relatively well-identified using the MICROFIL perfusion and micro-CT scanning method, which allows the evaluation and comparison of differences and changes of angiogenesis in tissue-engineered nerves implanted in vivo. PMID:26981108

  16. Accuracy of cancellous bone volume fraction measured by micro-CT scanning.

    PubMed

    Ding, M; Odgaard, A; Hvid, I

    1999-03-01

    Volume fraction, the single most important parameter in describing trabecular microstructure, can easily be calculated from three-dimensional reconstructions of micro-CT images. This study sought to quantify the accuracy of this measurement. One hundred and sixty human cancellous bone specimens which covered a large range of volume fraction (9.8-39.8%) were produced. The specimens were micro-CT scanned, and the volume fraction based on Archimedes' principle was determined as a reference. After scanning, all micro-CT data were segmented using individual thresholds determined by the scanner supplied algorithm (method I). A significant deviation of volume fraction from method I was found: both the y-intercept and the slope of the regression line were significantly different from those of the Archimedes-based volume fraction (p < 0.001). New individual thresholds were determined based on a calibration of volume fraction to the Archimedes-based volume fractions (method II). The mean thresholds of the two methods were applied to segment 20 randomly selected specimens. The results showed that volume fraction using the mean threshold of method I was underestimated by 4% (p = 0.001), whereas the mean threshold of method II yielded accurate values. The precision of the measurement was excellent. Our data show that care must be taken when applying thresholds in generating 3-D data, and that a fixed threshold may be used to obtain reliable volume fraction data. This fixed threshold may be determined from the Archimedes-based volume fraction of a subgroup of specimens. The threshold may vary between different materials, and so it should be determined whenever a study series is performed. PMID:10093033

  17. CT scanning carcases has no detrimental effect on the colour stability of M. longissimus dorsi from beef and sheep.

    PubMed

    Jose, C G; Pethick, D W; Jacob, R H; Gardner, G E

    2009-01-01

    This study investigated the effect of computerised tomography imaging (CT scan), for carcase composition determination, on the oxy/metmyoglobin ratio, hue and L(∗), a(∗) and b(∗) scores of M. longissimus dorsi from both beef and lamb. Beef and lamb M. longissimus dorsi were divided into four proportions and randomly allocated to one of the following treatments; CT 30 day aged; CT fresh; control 30 day aged; control fresh. Colour measurements were made over a 96h retail display period. CT scan had little effect on the colour of both lamb and beef across all colour parameters. There was a small negative affect observed in CT aged samples (P<0.05) for ratio, hue, a(∗) and b(∗) values, however these differences were so small that they are unlikely to impact upon the commercial shelf-life of the product. Other factors such as aging, species and vitamin E concentration play a much greater role in colour stability than CT. Aged M. longissimus dorsi clearly had a worse colour stability than the fresh packaged samples, while beef was a lot more colour stable than lamb. It appears that CT scan for the purpose of body composition determination will not have any commercially relevant impact on colour stability of both beef and lamb.

  18. [Exposure to CT scans in childhood and long-term cancer risk: A review of epidemiological studies].

    PubMed

    Baysson, Hélène; Journy, Neige; Roué, Tristan; Ducou-Lepointe, Hubert; Etard, Cécile; Bernier, Marie-Odile

    2016-02-01

    Amongst medical exams requiring ionizing radiation, computed tomography (CT) scans are used more frequently, including in children. These CT examinations are associated with absorbed doses that are much higher than those associated with conventional radiology. In comparison to adults, children have a greater sensitivity to radiation and a longer life span with more years at cancer risks. Five epidemiological studies on cancer risks after CT scan exposure during childhood were published between 2012 and 2015. The results of these studies are consistent and show an increase of cancer risks in children who have been exposed to several CT scans. However, methodological limits due to indication bias, retrospective assessment of radiation exposure from CT scans and lack of statistical power are to be taken into consideration. International projects such as EPI-CT (Epidemiological study to quantify risks for pediatric computerized tomography and to optimize dose), with a focus on dosimetric reconstruction and minimization of bias will provide more precise results. In the meantime, available results reinforce the necessity of justification and optimization of doses.

  19. [Exposure to CT scans in childhood and long-term cancer risk: A review of epidemiological studies].

    PubMed

    Baysson, Hélène; Journy, Neige; Roué, Tristan; Ducou-Lepointe, Hubert; Etard, Cécile; Bernier, Marie-Odile

    2016-02-01

    Amongst medical exams requiring ionizing radiation, computed tomography (CT) scans are used more frequently, including in children. These CT examinations are associated with absorbed doses that are much higher than those associated with conventional radiology. In comparison to adults, children have a greater sensitivity to radiation and a longer life span with more years at cancer risks. Five epidemiological studies on cancer risks after CT scan exposure during childhood were published between 2012 and 2015. The results of these studies are consistent and show an increase of cancer risks in children who have been exposed to several CT scans. However, methodological limits due to indication bias, retrospective assessment of radiation exposure from CT scans and lack of statistical power are to be taken into consideration. International projects such as EPI-CT (Epidemiological study to quantify risks for pediatric computerized tomography and to optimize dose), with a focus on dosimetric reconstruction and minimization of bias will provide more precise results. In the meantime, available results reinforce the necessity of justification and optimization of doses. PMID:26782078

  20. [Peripheral lung adenocarcinoma versus squamous cell carcinoma: evaluation with first-pass perfusion imaging using 64-detector row CT].

    PubMed

    Li, Yuan; Yang, Zhigang; Chen, Tianwu; Yu, Jianqun; Deng, Yuping; Li, Zhenlin

    2009-04-01

    The aim of this study was to elucidate the characteristics of time attenuation curve and CT perfusion parameters for pulmonary adenocarcinomas and squamous cell carcinomas. 58 cases of pulmonary adenocarcinomas and 27 cases of squamous cell carcinomas underwent first pass CT perfusion imaging with 64-row MDCT. Data were analyzed using commercial software to generate time attenuation curve (TAC) and CT perfusion parameters, including perfusion, peak enhanced (PE), time to peak (TTP), and blood volume (BV). For TAC, there were 36.2% of type I and 63.8% of type II in adenocarcinomas, while there were 22.2% of type I and 77.8% of type II in squamous cell carcinomas. There was not significant difference (P>0.05). Perfusion, PE, TTP and BV of adenocarcinomas were 63.2 +/- 45.4 ml x min(-1) x ml(-1), 60.2 +/- 46.6 Hu, 34.8 +/- 10.2 s and 34.3 +/- 23.6 ml x 100 g(-1), respectively, while 54.3 +/- 50.2 ml x min(-1) x ml(-1), 48.5 +/- 34.9 Hu, 36.1 +/- 11.2 s and 27.6 +/- 21.7 ml x 100 g(-1), for squamous cell carcinoma, respectively. No significant differences were found between groups (P>0.05). No significant differences in TAC and CT perfusion parameters were found between adenocarcinomas and squamous cell carcinomas.

  1. A prospective trial comparing FDG-PET/CT and CT to assess tumor response to cetuximab in patients with incurable squamous cell carcinoma of the head and neck

    PubMed Central

    Adkins, Douglas; Ley, Jessica; Dehdashti, Farrokh; Siegel, Marilyn J; Wildes, Tanya M; Michel, Loren; Trinkaus, Kathryn; Siegel, Barry A

    2014-01-01

    Computed tomography (CT), the standard method to assess tumor response to cetuximab in incurable squamous cell carcinoma of the head and neck (SCCHN), performs poorly as judged by the disparity between high disease control rate (46%) and short time to progression (TTP) (70 days). F-18 fluorodeoxyglucose positron emission tomography (FDG-PET)/CT is an alternative method to assess tumor response. The primary objective of this prospective trial was to evaluate the metabolic response of target lesions, assessed as the change in maximum standardized uptake value (SUVmax) on FDG-PET/CT before and after 8 weeks (cycle 1) of cetuximab. Secondary objectives were to compare tumor response by CT (RECIST 1.0) and FDG-PET/CT (EORTC criteria) following cycle 1, and determine TTP with continued cetuximab administration in patients with disease control by CT after cycle 1 but stratified for disease control or progression by FDG-PET/CT. Among 27 patients, the mean percent change of SUVmax of target lesions after cycle 1 was −21% (range: +72% to −81%); by FDG-PET/CT, partial response (PR)/stable disease (SD) occurred in 15 patients (56%) and progression in 12 (44%), whereas by CT, PR/SD occurred in 20 (74%) and progression in 7 (26%). FDG-PET/CT and CT assessments were discordant in 14 patients (P = 0.0029) and had low agreement (κ = 0.30; 95% confidence interval [CI]: 0.12, 0.48). With disease control by CT after cycle 1, median TTP was 166 days (CI: 86, 217) if the FDG-PET/CT showed disease control and 105 days (CI: 66, 159) if the FDG-PET/CT showed progression (P < 0.0001). Median TTP of the seven patients whose post cycle 1 CT showed progression compared to the 12 whose FDG-PET/CT showed progression were similar (53 [CI: 49, 56] vs. 61 [CI: 50, 105] days, respectively). FDG-PET/CT may be better than CT in assessing benefit of cetuximab in incurable SCCHN. PMID:25081631

  2. Moving metal artifact reduction in cone-beam CT scans with implanted cylindrical gold markers

    SciTech Connect

    Toftegaard, Jakob Fledelius, Walther; Worm, Esben S.; Poulsen, Per R.; Seghers, Dieter; Huber, Michael; Brehm, Marcus; Elstrøm, Ulrik V.

    2014-12-15

    Purpose: Implanted gold markers for image-guided radiotherapy lead to streaking artifacts in cone-beam CT (CBCT) scans. Several methods for metal artifact reduction (MAR) have been published, but they all fail in scans with large motion. Here the authors propose and investigate a method for automatic moving metal artifact reduction (MMAR) in CBCT scans with cylindrical gold markers. Methods: The MMAR CBCT reconstruction method has six steps. (1) Automatic segmentation of the cylindrical markers in the CBCT projections. (2) Removal of each marker in the projections by replacing the pixels within a masked area with interpolated values. (3) Reconstruction of a marker-free CBCT volume from the manipulated CBCT projections. (4) Reconstruction of a standard CBCT volume with metal artifacts from the original CBCT projections. (5) Estimation of the three-dimensional (3D) trajectory during CBCT acquisition for each marker based on the segmentation in Step 1, and identification of the smallest ellipsoidal volume that encompasses 95% of the visited 3D positions. (6) Generation of the final MMAR CBCT reconstruction from the marker-free CBCT volume of Step 3 by replacing the voxels in the 95% ellipsoid with the corresponding voxels of the standard CBCT volume of Step 4. The MMAR reconstruction was performed retrospectively using a half-fan CBCT scan for 29 consecutive stereotactic body radiation therapy patients with 2–3 gold markers implanted in the liver. The metal artifacts of the MMAR reconstructions were scored and compared with a standard MAR reconstruction by counting the streaks and by calculating the standard deviation of the Hounsfield units in a region around each marker. Results: The markers were found with the same autosegmentation settings in 27 CBCT scans, while two scans needed slightly changed settings to find all markers automatically in Step 1 of the MMAR method. MMAR resulted in 15 scans with no streaking artifacts, 11 scans with 1–4 streaks, and 3 scans

  3. TU-F-BRF-03: Effect of Radiation Therapy Planning Scan Registration On the Dose in Lung Cancer Patient CT Scans

    SciTech Connect

    Cunliffe, A; Contee, C; White, B; Justusson, J; Armato, S; Malik, R; Al-Hallaq, H

    2014-06-15

    Purpose: To characterize the effect of deformable registration of serial computed tomography (CT) scans on the radiation dose calculated from a treatment planning scan. Methods: Eighteen patients who received curative doses (≥60Gy, 2Gy/fraction) of photon radiation therapy for lung cancer treatment were retrospectively identified. For each patient, a diagnostic-quality pre-therapy (4–75 days) CT scan and a treatment planning scan with an associated dose map calculated in Pinnacle were collected. To establish baseline correspondence between scan pairs, a researcher manually identified anatomically corresponding landmark point pairs between the two scans. Pre-therapy scans were co-registered with planning scans (and associated dose maps) using the Plastimatch demons and Fraunhofer MEVIS deformable registration algorithms. Landmark points in each pretherapy scan were automatically mapped to the planning scan using the displacement vector field output from both registration algorithms. The absolute difference in planned dose (|ΔD|) between manually and automatically mapped landmark points was calculated. Using regression modeling, |ΔD| was modeled as a function of the distance between manually and automatically matched points (registration error, E), the dose standard deviation (SD-dose) in the eight-pixel neighborhood, and the registration algorithm used. Results: 52–92 landmark point pairs (median: 82) were identified in each patient's scans. Average |ΔD| across patients was 3.66Gy (range: 1.2–7.2Gy). |ΔD| was significantly reduced by 0.53Gy using Plastimatch demons compared with Fraunhofer MEVIS. |ΔD| increased significantly as a function of E (0.39Gy/mm) and SD-dose (2.23Gy/Gy). Conclusion: An average error of <4Gy in radiation dose was introduced when points were mapped between CT scan pairs using deformable registration. Dose differences following registration were significantly increased when the Fraunhofer MEVIS registration algorithm was used

  4. Computed tomography of the larynx: correlation with anatomic and pathologic studies in cases of laryngeal carcinoma

    SciTech Connect

    Mafee, M.F.; Schild, J.A.; Valvassori, G.E.; Capek, V.

    1983-04-01

    Seven patients with known carcinoma of the larynx underwent computed tomography (CT) of the larynx prior to surgery. Whole-mount sections of the extirpated larynx cut in the horizontal plane were compared with the corresponding level of the preoperaive CT sections to demonstrate the validity of CT scanning in the evaluation of tumors of the larynx. The results indicate that CT scanning accurately demonstrates the anatomic location and gross size of laryngeal tumor, although early invasion of the laryngeal cartilages may be difficult to diagnose with CT. It is concluded that preoperative CT scanning of the larynx is the radiologic procedure of choice for evaluating carcinoma of the larynx.

  5. Three-dimensional image of hepatocellular carcinoma under confocal laser scanning microscope

    PubMed Central

    Zhang, Wang-Hai; Zhu, Shi-Neng; Lu, Shi-Lun; Huang, Ya-Lin; Zhao, Peng

    2000-01-01

    AIM: To investigate the application of confocal laser scanning microscopy (CLSM) in tumor pathology and three-dimensional (3-D) reconstruction by CLSM in pathologic specimens of hepatocellular carcinoma (HCC). METHODS: The 30 μm thick sections were cut from the paraffin-embedded tissues of HCC, hyperplasia and normal liver, stained with DNA fluorescent probe YOYO-1 iodide and examined by CLSM to collect optical sections of nuclei and 3-D images reconstructed. RESULTS: HCC displayed chaotic arrangement of carcinoma cell nuclei, marked pleomorphism, indented and irregular nuclear surface, and irregular and coarse chromatin texture. CONCLUSION: The serial optical tomograms of CLSM can be used to create 3-D reconstruction of cancer cell nuclei. Such 3-D impressions might be helpful or even essential in making an accurate diagnosis. PMID:11819594

  6. Clinical Outcomes of Patients Receiving Integrated PET/CT-Guided Radiotherapy for Head and Neck Carcinoma

    SciTech Connect

    Vernon, Matthew R.; Maheshwari, Mohit; Schultz, Christopher J.; Michel, Michelle A.; Wong, Stuart J.; Campbell, Bruce H.; Massey, Becky L.; Wilson, J. Frank; Wang Dian

    2008-03-01

    Purpose: We previously reported the advantages of {sup 18}F-fluorodeoxyglucose-positron emission tomography (PET) fused with CT for radiotherapy planning over CT alone in head and neck carcinoma (HNC). The purpose of this study was to evaluate clinical outcomes and the predictive value of PET for patients receiving PET/CT-guided definitive radiotherapy with or without chemotherapy. Methods and Materials: From December 2002 to August 2006, 42 patients received PET/CT imaging as part of staging and radiotherapy planning. Clinical outcomes including locoregional recurrence, distant metastasis, death, and treatment-related toxicities were collected retrospectively and analyzed for disease-free and overall survival and cumulative incidence of recurrence. Results: Median follow-up from initiation of treatment was 32 months. Overall survival and disease-free survival were 82.8% and 71.0%, respectively, at 2 years, and 74.1% and 66.9% at 3 years. Of the 42 patients, seven recurrences were identified (three LR, one DM, three both LR and DM). Mean time to recurrence was 9.4 months. Cumulative risk of recurrence was 18.7%. The maximum standard uptake volume (SUV) of primary tumor, adenopathy, or both on PET did not correlate with recurrence, with mean values of 12.0 for treatment failures vs. 11.7 for all patients. Toxicities identified in those patients receiving intensity modulated radiation therapy were also evaluated. Conclusions: A high level of disease control combined with favorable toxicity profiles was achieved in a cohort of HNC patients receiving PET/CT fusion guided radiotherapy plus/minus chemotherapy. Maximum SUV of primary tumor and/or adenopathy was not predictive of risk of disease recurrence.

  7. Metastatic superscan in prostate carcinoma on gallium-68-prostate-specific membrane antigen positron emission tomography/computed tomography scan

    PubMed Central

    Agarwal, Krishan Kant; Tripathi, Madhavi; Kumar, Rajeev; Bal, Chandrasekhar

    2016-01-01

    We describe the imaging features of a metastatic superscan on gallium-68 Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as gallium-68-prostate-specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) imaging. 68Ga-PSMA is novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. This patient had a superscan of metastases on conventional bone scintigraphy and was referred for 68Ga-PSMA PET/CT to evaluate the feasibility of 177Lu-PSMA therapy. PMID:27095868

  8. 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.

  9. A study of the short- to long-phantom dose ratios for CT scanning without table translation

    SciTech Connect

    Li, Xinhua; Zhang, Da; Liu, Bob; Yang, Jie

    2014-09-15

    Purpose: For CT scanning in the stationary-table modes, AAPM Task Group 111 proposed to measure the midpoint dose on the central and peripheral axes of sufficiently long phantoms. Currently, a long cylindrical phantom is usually not available in many clinical facilities. The use of a long phantom is also challenging because of the heavy weight. In order to shed light on assessing the midpoint dose in CT scanning without table movement, the authors present a study of the short- to long-phantom dose ratios, and perform a cross-comparison of CT dose ratios on different scanner models. Methods: The authors performed Geant4-based Monte Carlo simulations with a clinical CT scanner (Somatom Definition dual source CT, Siemens Healthcare), and modeled dosimetry measurements using a 0.6 cm{sup 3} Farmer type chamber and a 10-cm long pencil ion chamber. The short (15 cm) to long (90 cm) phantom dose ratios were computed for two PMMA diameters (16 and 32 cm), two phantom axes (the center and the periphery), and a range of beam apertures (3–25 cm). The results were compared with the published data of previous studies with other multiple detector CT (MDCT) scanners and cone beam CT (CBCT) scanners. Results: The short- to long-phantom dose ratios changed with beam apertures but were insensitive to beam qualities (80–140 kV, the head and body bowtie filters) and MDCT and CBCT scanner models. Conclusions: The short- to long-phantom dose ratios enable medical physicists to make dosimetry measurements using the standard CT dosimetry phantoms and a Farmer chamber or a 10 cm long pencil chamber, and to assess the midpoint dose in long phantoms. This method provides an effective approach for the dosimetry of CBCT scanning in the stationary-table modes, and is useful for perfusion and interventional CT.

  10. Evaluation of radiation dose and image quality of CT scan for whole-body pediatric PET/CT: A phantom study

    SciTech Connect

    Yang, Ching-Ching; Liu, Shu-Hsin; Mok, Greta S. P.; Wu, Tung-Hsin

    2014-09-15

    Purpose: This study aimed to tailor the CT imaging protocols for pediatric patients undergoing whole-body PET/CT examinations with appropriate attention to radiation exposure while maintaining adequate image quality for anatomic delineation of PET findings and attenuation correction of PET emission data. Methods: The measurements were made by using three anthropomorphic phantoms representative of 1-, 5-, and 10-year-old children with tube voltages of 80, 100, and 120 kVp, tube currents of 10, 40, 80, and 120 mA, and exposure time of 0.5 s at 1.75:1 pitch. Radiation dose estimates were derived from the dose-length product and were used to calculate risk estimates for radiation-induced cancer. The influence of image noise on image contrast and attenuation map for CT scans were evaluated based on Pearson's correlation coefficient and covariance, respectively. Multiple linear regression methods were used to investigate the effects of patient age, tube voltage, and tube current on radiation-induced cancer risk and image noise for CT scans. Results: The effective dose obtained using three anthropomorphic phantoms and 12 combinations of kVp and mA ranged from 0.09 to 4.08 mSv. Based on our results, CT scans acquired with 80 kVp/60 mA, 80 kVp/80 mA, and 100 kVp/60 mA could be performed on 1-, 5-, and 10-year-old children, respectively, to minimize cancer risk due to CT scans while maintaining the accuracy of attenuation map and CT image contrast. The effective doses of the proposed protocols for 1-, 5- and 10-year-old children were 0.65, 0.86, and 1.065 mSv, respectively. Conclusions: Low-dose pediatric CT protocols were proposed to balance the tradeoff between radiation-induced cancer risk and image quality for patients ranging in age from 1 to 10 years old undergoing whole-body PET/CT examinations.

  11. Topographical investigations of human ovarian-carcinoma polymorphic epithelial mucin by scanning tunnelling microscopy.

    PubMed Central

    Roberts, C J; Sekowski, M; Davies, M C; Jackson, D E; Price, M R; Tendler, S J

    1992-01-01

    Human polymorphic epithelial mucin is a high-molecular-mass glycoprotein that associates to provide protection to the epithelial-cell surface and may afford the malignant cell a selective advantage for growth. The scanning-tunnelling-microscopy micrographs obtained in the present study identify the purified human ovarian-carcinoma polymorphic epithelial mucin glycoproteins as rod-shaped molecules of mixed length. The dimensions of the individual molecules range from 25 to 45 nm in length and are 3-4 nm in width. The images further suggest that lateral association of the rods occurs. Images Fig. 1. Fig. 2. PMID:1567366

  12. [Cerebral neuroblastoma in the adult. Clinical and C.T. scan aspects (author's transl)].

    PubMed

    Boudouresques, G; Boudouresques, J; Grisoli, F; Hassoun, J; Delpuech, F; Vincentelli, F; Khalil, R

    1980-01-01

    The case of a thirty two years old patient with a frontal syndrome developing over the last three years is reported. CT scan showed a large calcified lesion, situated on the median line enhanced by iodine. The patient was operated. Ultrastructural and histologie studies concluded that it the tumor was a neuroblastoma. After operation an unquestionable amelioration of the frontal disorders appeared. Facial paralysis with a inverse automatic-voluntary dissociation and an underuse of motricity, both left-sided, after cortectomy of the right-sided premotor area were observed. We therefore suggest that the lesion of the external premotor cortex was responsible of the facial paralysis with an inverse automatic voluntary dissociation and of the underuse the left side.

  13. Cerebral embolism: local CFBF and edema measured by CT scanning and Xe inhalation. [Baboons

    SciTech Connect

    Meyer, J.S.; Yamamoto, M.; Hayman, L.A.; Sakai, F.; Nakajima, S.; Armstrong, D.

    1980-01-01

    Serial CT scans were made in baboons after cerebral embolization during stable Xe inhalation for measuring local values for CBF and lambda (brain-blood partition or solubility coefficients), followed by iodine infusion for detecting blood-brain barrier (BBB) damage. Persistent zones of zero flow surrounded by reduced flow were measured predominantly in subcortical regions, which showed gross and microscopic evidence of infarction at necropsy. Overlying cortex was relatively spared. Reduced lambda values attributed to edema appeared within 3 to 5 minutes and progressed up to 60 minutes. Damage to BBB with visible transvascular seepage of iodine began to appear 1 to 1 1/2 hours after embolism. In chronic animals, lambda values were persistently reduced in areas showing histologic infarction. Contralateral hemispheric CBF increased for the first 15 minutes after embolism, followed by progressive reduction after 30 minutes (diaschisis).

  14. Fourier-based reconstruction via alternating direction total variation minimization in linear scan CT

    NASA Astrophysics Data System (ADS)

    Cai, Ailong; Wang, Linyuan; Yan, Bin; Zhang, Hanming; Li, Lei; Xi, Xiaoqi; Li, Jianxin

    2015-03-01

    In this study, we consider a novel form of computed tomography (CT), that is, linear scan CT (LCT), which applies a straight line trajectory. Furthermore, an iterative algorithm is proposed for pseudo-polar Fourier reconstruction through total variation minimization (PPF-TVM). Considering that the sampled Fourier data are distributed in pseudo-polar coordinates, the reconstruction model minimizes the TV of the image subject to the constraint that the estimated 2D Fourier data for the image are consistent with the 1D Fourier transform of the projection data. PPF-TVM employs the alternating direction method (ADM) to develop a robust and efficient iteration scheme, which ensures stable convergence provided that appropriate parameter values are given. In the ADM scheme, PPF-TVM applies the pseudo-polar fast Fourier transform and its adjoint to iterate back and forth between the image and frequency domains. Thus, there is no interpolation in the Fourier domain, which makes the algorithm both fast and accurate. PPF-TVM is particularly useful for limited angle reconstruction in LCT and it appears to be robust against artifacts. The PPF-TVM algorithm was tested with the FORBILD head phantom and real data in comparisons with state-of-the-art algorithms. Simulation studies and real data verification suggest that PPF-TVM can reconstruct higher accuracy images with lower time consumption.

  15. Scale-invariant registration of monocular endoscopic images to CT-scans for sinus surgery.

    PubMed

    Burschka, Darius; Li, Ming; Ishii, Masaru; Taylor, Russell H; Hager, Gregory D

    2005-10-01

    In this paper, we present a novel method for intra-operative registration directly from monocular endoscopic images. This technique has the potential to provide a more accurate surface registration at the surgical site than existing methods. It can operate autonomously from as few as two images and can be particularly useful in revision cases where surgical landmarks may be absent. A by-product of video registration is an estimate of the local surface structure of the anatomy, thus providing the opportunity to dynamically update anatomical models as the surgery progresses. Our approach is based on a previously presented method [Burschka, D., Hager, G.D., 2004. V-GPS (SLAM):--Vision-based inertial system for mobile robots. In: Proceedings of ICRA, 409-415] for reconstruction of a scaled 3D model of the environment from unknown camera motion. We use this scaled reconstruction as input to a PCA-based algorithm that registers the reconstructed data to the CT data and recovers the scale and pose parameters of the camera in the coordinate frame of the CT scan. The result is used in an ICP registration step to refine the registration estimates. The details of our approach and the experimental results with a phantom of a human skull and a head of a pig cadaver are presented in this paper.

  16. Postoperative follow-up of juvenile nasopharyngeal angiofibromas: assessment by CT scan and MR imaging.

    PubMed

    Chagnaud, C; Petit, P; Bartoli, J; Champsaur, P; Gaubert, J; Dessi, P; Zanaret, M; Cannoni, M; Moulin, G

    1998-01-01

    The purpose of this study was to assess the radiological findings after surgical removal of juvenile nasopharyngeal angiofibromas (JNA). The postoperative CT and MRI scans of ten patients were reviewed. The cured group included six patients. The non-controlled group included six patients with eight recurrences. Two patients belonged to both groups as they were also followed and cured after surgery for relapse. Four recurrences were asymptomatic and diagnosed by imaging. The imaging patterns were matched to the patients clinical status and endoscopic findings. In the cured group, non-enhanced residual soft tissue masses were seen in all cases. In the non-controlled group, recurrence was always demonstrated on early postoperative CT or MR as a dramatically enhanced mass. The recurrence was located in the lateral or superior aspect of the nasopharynx (n = 3), deep to the fossa of Rosenmuller (n = 4) or out of the nasopharynx (n = 1). In two cases a remaining enhanced mass disappeared spontaneously on iterated examinations. Because of numerous asymptomatic relapses, a radiological workup is recommended four months after surgery, even in patients with normal endoscopy, to rule out posterolateral or extranasopharyngeal recurrences. Spontaneous evolution of residual masses must be appreciated on iterated imaging examinations.

  17. Automatic three-dimensional rib centerline extraction from CT scans for enhanced visualization and anatomical context

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Sowmya; Alvino, Christopher; Grady, Leo; Kiraly, Atilla

    2011-03-01

    We present a complete automatic system to extract 3D centerlines of ribs from thoracic CT scans. Our rib centerline system determines the positional information for the rib cage consisting of extracted rib centerlines, spinal canal centerline, pairing and labeling of ribs. We show an application of this output to produce an enhanced visualization of the rib cage by the method of Kiraly et al., in which the ribs are digitally unfolded along their centerlines. The centerline extraction consists of three stages: (a) pre-trace processing for rib localization, (b) rib centerline tracing, and (c) post-trace processing to merge the rib traces. Then we classify ribs from non-ribs and determine anatomical rib labeling. Our novel centerline tracing technique uses the Random Walker algorithm to segment the structural boundary of the rib in successive 2D cross sections orthogonal to the longitudinal direction of the ribs. Then the rib centerline is progressively traced along the rib using a 3D Kalman filter. The rib centerline extraction framework was evaluated on 149 CT datasets with varying slice spacing, dose, and under a variety of reconstruction kernels. The results of the evaluation are presented. The extraction takes approximately 20 seconds on a modern radiology workstation and performs robustly even in the presence of partial volume effects or rib pathologies such as bone metastases or fractures, making the system suitable for assisting clinicians in expediting routine rib reading for oncology and trauma applications.

  18. Surgical navigation display system using volume rendering of intraoperatively scanned CT images.

    PubMed

    Hayashibe, Mitsuhiro; Suzuki, Naoki; Hattori, Asaki; Otake, Yoshito; Suzuki, Shigeyuki; Nakata, Norio

    2006-09-01

    As operative procedures become more complicated, simply increasing the number of devices will not facilitate such operations. It is necessary to consider the ergonomics of the operating environment, especially with regard to the provision of navigation data, the prevention of technical difficulties, and the comfort of the operating room staff. We have designed and created a data-fusion interface that enables volumetric Maximum Intensity Projection (MIP) image navigation using intra-operative mobile 3D-CT data in the OR. The 3D volumetric data reflecting a patient's inner structure is directly displayed on the monitor through video images of the surgical field using a 3D optical tracking system, a ceiling-mounted articulating monitor, and a small-size video camera mounted at the back of the monitor. The system performance and accuracy was validated experimentally. This system provides a novel interface for a surgeon with volume rendering of intra-operatively scanned CT images, as opposed to preoperative images.

  19. Fully automated shape model positioning for bone segmentation in whole-body CT scans

    NASA Astrophysics Data System (ADS)

    Fränzle, A.; Sumkauskaite, M.; Hillengass, J.; Bäuerle, T.; Bendl, R.

    2014-03-01

    Analysing osteolytic and osteoblastic bone lesions in systematically affected skeletons, e.g. in multiple myeloma or bone metastasis, is a complex task. Quantification of the degree of bone destruction needs segmentation of all lesions but cannot be managed manually. Automatic bone lesion detection is necessary. Our future objective is comparing modified bones with healthy shape models. For applying model based strategies successfully, identification and position information of single bones is necessary. A solution to these requirements based on bone medullary cavities is presented in this paper. Medullary cavities are useful for shape model positioning since they have similar position and orientation as the bone itself but can be separated more easily. Skeleton segmentation is done by simple thresholding. Inside the skeleton medullary cavities are segmented by a flood filling algorithm. The filled regions are considered as medullary cavity objects. To provide automatic shape model selection, medullary cavity objects are assigned to bone structures with pattern recognition. To get a good starting position for shape models, principal component analysis of medullary cavities is performed. Bone identification was tested on 14 whole-body low-dose CT scans of multiple myeloma patients. Random forest classification assigns medullary cavities of long bones to the corresponding bone (overall accuracy 90%). Centroid and first principal component of medullary cavity are sufficiently similar to those of bone (mean centroid difference 21.7 mm, mean difference angle 1.54° for all long bones of one example patient) and therefore suitable for shape model initialization. This method enables locating long bone structures in whole-body CT scans and provides useful information for a reasonable shape model initialization.

  20. Characterizing Functional Lung Heterogeneity in COPD Using Reference Equations for CT Scan-Measured Lobar Volumes

    PubMed Central

    Diaz, Alejandro A.; Curran-Everett, Douglas; Muralidhar, Nivedita; Hersh, Craig P.; Zach, Jordan A.; Schroeder, Joyce; Lynch, David A.; Celli, Bartolome; Washko, George R.

    2013-01-01

    Background: CT scanning is increasingly used to characterize COPD. Although it is possible to obtain CT scan-measured lung lobe volumes, normal ranges remain unknown. Using COPDGene data, we developed reference equations for lobar volumes at maximal inflation (total lung capacity [TLC]) and relaxed exhalation (approximating functional residual capacity [FRC]). Methods: Linear regression was used to develop race-specific (non-Hispanic white [NHW], African American) reference equations for lobar volumes. Covariates included height and sex. Models were developed in a derivation cohort of 469 subjects with normal pulmonary function and validated in 546 similar subjects. These cohorts were combined to produce final prediction equations, which were applied to 2,191 subjects with old GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II to IV COPD. Results: In the derivation cohort, women had smaller lobar volumes than men. Height positively correlated with lobar volumes. Adjusting for height, NHWs had larger total lung and lobar volumes at TLC than African Americans; at FRC, NHWs only had larger lower lobes. Age and weight had no effect on lobar volumes at TLC but had small effects at FRC. In subjects with COPD at TLC, upper lobes exceeded 100% of predicted values in GOLD II disease; lower lobes were only inflated to this degree in subjects with GOLD IV disease. At FRC, gas trapping was severe irrespective of disease severity and appeared uniform across the lobes. Conclusions: Reference equations for lobar volumes may be useful in assessing regional lung dysfunction and how it changes in response to pharmacologic therapies and surgical or endoscopic lung volume reduction. PMID:23699785

  1. Methodologies for Development of Patient Specific Bone Models from Human Body CT Scans

    NASA Astrophysics Data System (ADS)

    Chougule, Vikas Narayan; Mulay, Arati Vinayak; Ahuja, Bharatkumar Bhagatraj

    2016-06-01

    This work deals with development of algorithm for physical replication of patient specific human bone and construction of corresponding implants/inserts RP models by using Reverse Engineering approach from non-invasive medical images for surgical purpose. In medical field, the volumetric data i.e. voxel and triangular facet based models are primarily used for bio-modelling and visualization, which requires huge memory space. On the other side, recent advances in Computer Aided Design (CAD) technology provides additional facilities/functions for design, prototyping and manufacturing of any object having freeform surfaces based on boundary representation techniques. This work presents a process to physical replication of 3D rapid prototyping (RP) physical models of human bone from various CAD modeling techniques developed by using 3D point cloud data which is obtained from non-invasive CT/MRI scans in DICOM 3.0 format. This point cloud data is used for construction of 3D CAD model by fitting B-spline curves through these points and then fitting surface between these curve networks by using swept blend techniques. This process also can be achieved by generating the triangular mesh directly from 3D point cloud data without developing any surface model using any commercial CAD software. The generated STL file from 3D point cloud data is used as a basic input for RP process. The Delaunay tetrahedralization approach is used to process the 3D point cloud data to obtain STL file. CT scan data of Metacarpus (human bone) is used as the case study for the generation of the 3D RP model. A 3D physical model of the human bone is generated on rapid prototyping machine and its virtual reality model is presented for visualization. The generated CAD model by different techniques is compared for the accuracy and reliability. The results of this research work are assessed for clinical reliability in replication of human bone in medical field.

  2. Heart region segmentation from low-dose CT scans: an anatomy based approach

    NASA Astrophysics Data System (ADS)

    Reeves, Anthony P.; Biancardi, Alberto M.; Yankelevitz, David F.; Cham, Matthew D.; Henschke, Claudia I.

    2012-02-01

    Cardiovascular disease is a leading cause of death in developed countries. The concurrent detection of heart diseases during low-dose whole-lung CT scans (LDCT), typically performed as part of a screening protocol, hinges on the accurate quantification of coronary calcification. The creation of fully automated methods is ideal as complete manual evaluation is imprecise, operator dependent, time consuming and thus costly. The technical challenges posed by LDCT scans in this context are mainly twofold. First, there is a high level image noise arising from the low radiation dose technique. Additionally, there is a variable amount of cardiac motion blurring due to the lack of electrocardiographic gating and the fact that heart rates differ between human subjects. As a consequence, the reliable segmentation of the heart, the first stage toward the implementation of morphologic heart abnormality detection, is also quite challenging. An automated computer method based on a sequential labeling of major organs and determination of anatomical landmarks has been evaluated on a public database of LDCT images. The novel algorithm builds from a robust segmentation of the bones and airways and embodies a stepwise refinement starting at the top of the lungs where image noise is at its lowest and where the carina provides a good calibration landmark. The segmentation is completed at the inferior wall of the heart where extensive image noise is accommodated. This method is based on the geometry of human anatomy and does not involve training through manual markings. Using visual inspection by an expert reader as a gold standard, the algorithm achieved successful heart and major vessel segmentation in 42 of 45 low-dose CT images. In the 3 remaining cases, the cardiac base was over segmented due to incorrect hemidiaphragm localization.

  3. Longitudinal dose distribution and energy absorption in PMMA and water cylinders undergoing CT scans

    SciTech Connect

    Li, Xinhua; Zhang, Da; Liu, Bob

    2014-10-15

    Purpose: The knowledge of longitudinal dose distribution provides the most direct view of the accumulated dose in computed tomography (CT) scanning. The purpose of this work was to perform a comprehensive study of dose distribution width and energy absorption with a wide range of subject sizes and beam irradiated lengths. Methods: Cumulative dose distribution along the z-axis was calculated based on the previously published CT dose equilibration data by Li, Zhang, and Liu [Med. Phys. 40, 031903 (10pp.) (2013)] and a mechanism for computing dose on axial lines by Li, Zhang, and Liu [Med. Phys. 39, 5347–5352 (2012)]. Full width at half maximum (FWHM), full width at tenth maximum (FWTM), the total energy (E) absorbed in a small cylinder of unit mass per centimeter square about the central or peripheral axis, and the energy (E{sub in}) absorbed inside irradiated length (L) were subsequently extracted from the dose distribution. Results: Extensive results of FWHM, FWTM, and E{sub in}/E were presented on the central and peripheral axes of infinitely long PMMA (diameters 6–50 cm) and water (diameters 6–55 cm) cylinders with L < 100 cm. FWHM was greater than the primary beam width only on the central axes of large phantoms and also with L ranging from a few centimeter to about 33 cm. FWTM generally increased with phantom diameter, and could be up to 32 cm longer than irradiated length, depending on L, phantom diameter and axis, but was insensitive to phantom material (PMMA or water). E{sub in}/E increased with L and asymptotically approached unity for large L. As phantom diameter increased, E{sub in}/E generally decreased, but asymptotically approached constant levels on the peripheral axes of large phantoms. A heuristic explanation of dose distribution width results was presented. Conclusions: This study enables the reader to gain a comprehensive view of dose distribution width and energy absorption and provides useful data for estimating doses to organs inside or

  4. Early prediction of response of sorafenib on hepatocellular carcinoma by CT perfusion imaging: an animal study

    PubMed Central

    Shi, G; Wang, L; Liu, X; Wu, R

    2014-01-01

    Objective: This study evaluated the feasibility of CT perfusion parameters for the early efficacy prediction of sorafenib in the treatment of hepatocellular carcinoma (HCC) in rats. Methods: CT hepatic perfusion measurements were performed in the livers of 40 rats implanted with rat HCC. The rats in the experimental group (n = 28) were treated by oral gavage with sorafenib (20 mg per day), whereas the rats in the control group (n = 12) were treated by normal saline. Rats were classified into the responder group if the maximum diameter of their tumour had decreased 21 days after treatment, whereas the other rats were classified into the non-responder group. Data were analysed using the Pearson correlation analysis or analysis of variance. Results: CT perfusion was used to depict haemodynamic changes before and after treatment. The arterial liver perfusion was significantly decreased in the responder group on Day 11 after treatment with sorafenib (from 71.5 to 53.4 ml min−1 100 ml−1), whereas no significant changes were observed in the non-responder group (p = 0.87). The maximum diameter of the tumour was also significantly decreased in the responder group on Day 21 after treatment (p = 0.042), whereas the maximum tumour diameter was significantly increased in the control group (p = 0.001). Conclusion and advances in knowledge: CT perfusion could be used to quantitatively analyse the haemodynamic changes in the treatment of HCC with sorafenib, which indicates that this approach may be developed for the early prediction of treatment efficacy for sorafenib. PMID:24452058

  5. Metastatic poorly differentiated prostatic carcinoma with neuroendocrine differentiation: negative on 68Ga-PSMA PET/CT.

    PubMed

    Chakraborty, Partha Sarathi; Tripathi, Madhavi; Agarwal, Krishan Kant; Kumar, Rajeev; Vijay, Maneesh Kumar; Bal, Chandrasekhar

    2015-02-01

    Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as Ga-PSMA, is a novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. Its major advantage is the sensitive detection of lesions even at low prostate-specific antigen level and high target-to-background ratios obtained in metastatic lesions, which is better than that obtained with F-fluoromethylcholine. We present the case of a 28-year-old man with poorly differentiated prostate carcinoma with neuroendocrine differentiation, whose lesions did not show significant Ga-PSMA localization. As literature on utility of Ga-PSMA PET/CT for imaging prostate carcinoma grows, it is important to be aware of potential false negatives that could influence study results.

  6. Detection accuracy of condylar defects in cone beam CT images scanned with different resolutions and units

    PubMed Central

    Zhang, Z-l; Shi, X-q; Ma, X-c

    2014-01-01

    Objectives: To assess the impact of spatial resolution and cone beam CT (CBCT) unit on CBCT images for the detection accuracy of condylar defects. Methods: 42 temporomandibular joints were scanned, respectively, with the CBCT units ProMax® 3D (Planmeca Oy, Helsinki, Finland) and DCT PRO (Vatech, Co., Ltd., Yongin-Si, Republic of Korea) at normal and high resolutions. Seven dentists evaluated all the test images with respect to the presence or the absence of condylar defects. Receiver operating characteristic curve analysis was employed to define the detection accuracy. Two-way analysis of variance was used to analyse the values under the receiver operating characteristic curves for the differences among imaging groups and observers. Intraobserver variation was analysed using the Wilcoxon test. Results: Macroscopic anatomy examination revealed that, of the 42 temporomandibular joint condylar surfaces, 18 were normal and 24 had defects on the surface of condyles. No significant differences were found between the images scanned with normal and high resolutions for both CBCT units ProMax 3D (p = 0.119) and DCT PRO (p = 0.740). Significant differences exist between image groups of DCT PRO and ProMax 3D (p < 0.05). Neither the inter- nor the intraobserver variability were significant. Conclusions: The spatial resolution per se did not have an impact on the detection accuracy of condylar defects. The detection accuracy of condylar defects highly depends on the CBCT unit used for examination. PMID:24408818

  7. Planned FDG PET-CT Scan in Follow-Up Detects Disease Progression in Patients With Locally Advanced NSCLC Receiving Curative Chemoradiotherapy Earlier Than Standard CT

    PubMed Central

    Pan, Yi; Brink, Carsten; Schytte, Tine; Petersen, Henrik; Wu, Yi-long; Hansen, Olfred

    2015-01-01

    Abstract The role of positron emission tomography-computed tomography (PET-CT) in surveillance of patients with nonsmall cell lung cancer (NSCLC) treated with curatively intended chemoradiotherapy remains controversial. However, conventional chest X-ray and computed tomography (CT) are of limited value in discriminating postradiotherapy changes from tumor relapse. The aim of this study was to evaluate the clinical value of PET-CT scan in the follow-up for patients with locally advanced (LA) NSCLC receiving concomitant chemoradiotherapy (CCRT). Between 2009 and 2013, eligible patients with stages IIB–IIIB NSCLC were enrolled in the clinical trial NARLAL and treated in Odense University Hospital (OUH). All patients had a PET-CT scan scheduled 9 months (PET-CT9) after the start of the radiation treatment in addition to standard follow-up (group A). Patients who presented with same clinical stage of NSCLC and received similar treatment, but outside protocol in OUH during this period were selected as control group (group B). Patients in group B were followed in a conventional way without PET-CT9. All patients were treated with induction chemotherapy followed by CCRT. Group A included 37 and group B 55 patients. The median follow-up was 16 months. Sixty-six (72%) patients were diagnosed with progression after treatment. At the time of tumor progression, patients in group A had better performance status (PS) than those in group B (P = 0.02). Because of death (2 patients), poor PS (3) or retreatment of relapse (9), only 23 patients had PET-CT9 in group A. Eleven (48%) patients were firstly diagnosed with progression by PET-CT9 without any clinical symptoms of progression. The median progression-free survival (PFS) was 8.8 months in group A and 12.5 months in group B (P = 0.04). Hazard function PFS showed that patients in group A had higher risk of relapse than in group B. Additional FDG PET-CT scan at 9 months in surveillance increases probability of early

  8. Conversion of a Micro-CT Scanned Rock Fracture Into a Useful Model

    SciTech Connect

    Crandall, Dustin; Bromhal, Grant; Smith, Duane

    2009-01-01

    Within geologic reservoirs the flow of fluids through fractures is often orders of magnitude greater than through the surrounding, low-permeability rock. Because of the number and size of fractures in geological fields, reservoir-scale discrete-fracture simulators often model fluid motion through fractures as flow through narrow, parallel plates. In reality fractures within rock are narrow openings between two rough rock surfaces. In order to model the geometry of an actual fracture in rock, a ~9 cm by 2.5 cm fracture within Berea sandstone was created and the aperture distribution was obtained with micro-Computed Tomography (CT) scans by Karpyn et al. [1]. The original scans had a volume-pixel (voxel) resolution of 27 by 27 by 32 microns. This data was up-scaled to voxels with 120 microns to a side to facilitate data transfer and for practicality of use. Using three separate reconstruction techniques, six different fracture meshes were created from this up-scaled data set, each with slightly different final geometries. Flow through each of these fracture meshes was evaluated using the finite-volume simulator FLUENT. While certain features of the fracture meshes, such as the shape of the fracture aperture distributions and overall volume of the void, remained similar between the different geometric reconstructions, the flow in different models was observed to vary dramatically. Rough fracture walls induced more tortuous flow paths and a higher resistance to flow. Natural fractures do vary in-situ, due to sidewall dissolution and mineral precipitation, smoothing and coarsening fracture walls respectively. Thus for our study the range of fracture properties was actually beneficial, allowing us to describe the flow through a range of fracture types. A compromise between capturing the geometric details within a domain of interest and a tractable computational mesh must always be addressed when flow through a physical geometry is modeled. The fine level of detail that

  9. Are routine preoperative CT scans necessary in adult cochlear implantation? Implications for the allocation of resources in cochlear implant programs.

    PubMed

    Kenway, Bruno; Vlastarakos, Petros V; Kasbekar, Anand V; Axon, Patrick R; Donnelly, Neil

    2016-08-01

    Our aim was to critically assess the influence of preoperative computed tomography (CT) scans on implantation decisions for adult cochlear implant candidates. The working hypothesis was that these routine scans might not provide critical additional information in most adult cochlear implant candidates. The charts of 175 adults with unilateral cochlear implantation were reviewed. Preoperative CT scan reports were audited, and scans with reported pathology were examined by an Otologist/ENT Surgeon. Clinic notes and multidisciplinary team meeting summaries were also analyzed to assess whether the results of the radiology report had influenced the decision to implant or the laterality of implantation. Twenty-five of the 175 scans (14.3%) showed an abnormality. Five of those 25 scans showed evidence of previous surgeries already known to the clinicians. Of the remaining 20 scans, 17 showed abnormalities, including wide vestibular aqueducts, Mondini deformities, and varying degrees of otospongiosis, the identification of which can be considered preoperatively helpful. Of the 175 scans, 3 (1.7%) demonstrated abnormalities that influenced the side of implantation or the decision to implant and, therefore, had an impact on treatment. We conclude that a preoperative CT scan seems to have an impact on treatment in only a small percentage of adult cochlear implantees. Hence, it may only need to be performed in patients with a history or clinical suspicion of meningitis or otosclerosis, if the individual was born deaf or became deaf before the age of 16, or if there are other clinical reasons to scan (e.g., otoscopic appearance). The related resources can be allocated to other facets of cochlear implant programs. PMID:27551842

  10. Incorporating Radiology into Medical Gross Anatomy: Does the Use of Cadaver CT Scans Improve Students' Academic Performance in Anatomy?

    ERIC Educational Resources Information Center

    Lufler, Rebecca S.; Zumwalt, Ann C.; Romney, Carla A.; Hoagland, Todd M.

    2010-01-01

    Radiological images show anatomical structures in multiple planes and may be effective for teaching anatomical spatial relationships, something that students often find difficult to master. This study tests the hypotheses that (1) the use of cadaveric computed tomography (CT) scans in the anatomy laboratory is positively associated with…

  11. Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study

    PubMed Central

    Pearce, Mark S; Salotti, Jane A; Little, Mark P; McHugh, Kieran; Lee, Choonsik; Kim, Kwang Pyo; Howe, Nicola L; Ronckers, Cecile M; Rajaraman, Preetha; Craft, Alan W; Parker, Louise; de González, Amy Berrington

    2012-01-01

    Summary Background Although CT scans are very useful clinically, potential cancer risks exist from associated ionising radiation, in particular for children who are more radiosensitive than adults. We aimed to assess the excess risk of leukaemia and brain tumours after CT scans in a cohort of children and young adults. Methods In our retrospective cohort study, we included patients without previous cancer diagnoses who were first examined with CT in National Health Service (NHS) centres in England, Wales, or Scotland (Great Britain) between 1985 and 2002, when they were younger than 22 years of age. We obtained data for cancer incidence, mortality, and loss to follow-up from the NHS Central Registry from Jan 1, 1985, to Dec 31, 2008. We estimated absorbed brain and red bone marrow doses per CT scan in mGy and assessed excess incidence of leukaemia and brain tumours cancer with Poisson relative risk models. To avoid inclusion of CT scans related to cancer diagnosis, follow-up for leukaemia began 2 years after the first CT and for brain tumours 5 years after the first CT. Findings During follow-up, 74 of 178 604 patients were diagnosed with leukaemia and 135 of 176 587 patients were diagnosed with brain tumours. We noted a positive association between radiation dose from CT scans and leukaemia (excess relative risk [ERR] per mGy 0·036, 95% CI 0·005–0·120; p=0·0097) and brain tumours (0·023, 0·010–0·049; p<0·0001). Compared with patients who received a dose of less than 5 mGy, the relative risk of leukaemia for patients who received a cumulative dose of at least 30 mGy (mean dose 51·13 mGy) was 3·18 (95% CI 1·46–6·94) and the relative risk of brain cancer for patients who received a cumulative dose of 50–74 mGy (mean dose 60·42 mGy) was 2·82 (1·33–6·03). Interpretation Use of CT scans in children to deliver cumulative doses of about 50 mGy might almost triple the risk of leukaemia and doses of about 60 mGy might triple the risk of brain

  12. FDG PET with contrast-enhanced CT: a critical imaging tool for laryngeal carcinoma.

    PubMed

    Chu, Mae Mae A Y; Kositwattanarerk, Arpakorn; Lee, David J; Makkar, Jasnit S; Genden, Eric M; Kao, Johnny; Packer, Stuart H; Som, Peter M; Kostakoglu, Lale

    2010-09-01

    Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has evolved to be an essential imaging modality in the evaluation of laryngeal carcinoma. Although the modality has limited utility in assessing the extent of the primary tumor, FDG PET has proved to be superior to anatomic modalities in the detection of lymph node and distant metastases. The role of FDG PET in the evaluation of patients with laryngeal tumors that are clinically classified as N0 has not shown consistent usefulness because of the innate resolution limitations of the camera. In the posttherapy setting, however, FDG PET has consistently demonstrated a high negative predictive value in the identification of recurrent disease, both during the course of therapy and during long-term follow-up. In addition, contrast material-enhanced computed tomography (CT) in conjunction with FDG PET has demonstrated a complementary role by allowing for superior anatomic coregistration and therefore more definitive diagnosis. There is sufficient evidence that with further advances in PET technology, this modality will likely become more useful in the detection of small lesions and occult nodal disease, as well as in guiding the management of laryngeal carcinoma. PMID:20833855

  13. CT scan evaluation of glenoid bone and pectoralis major tendon: interest in shoulder prosthesis

    PubMed Central

    Obert, Laurent; Peyron, Christelle; Boyer, Etienne; Menu, Gauthier; Loisel, François; Aubry, Sébastien

    2016-01-01

    Introduction: The shoulder arthroplasty brings satisfaction to patients in terms of quality of life and indolence. However whether anatomic implant or reverse, it does not escape from the loosening of the glenoid component. Moreover, optimal implantation is required to ensure the functional outcome without shortening of the arm. The purpose of this study is obtain CT scan evaluation of the glenoid bone stock in order to optimize glenoid component implantation and obtain a reference to determine optimal humeral component placement in case of humeral proximal fracture. Materials and methods: Between 2010 and 2011 we have analyzed 200 intact shoulder’s CT. We measured maximal and minimal width in the transverse plane of the glenoid, the distance from the pectoralis major (PM) tendon to the humeral head, the greater tubercle, change of curvature and the anatomical neck. Results: Mean maximum width was 27.4 ± 3.4 mm and mean minimum width was 15.5 ± 2.8 mm. Distances between upper edge of PM tendon to: humeral head, greater tubercle, change of curvature and anatomical neck were respectively: 67.6 ± 9.98 mm, 57.8 ± 10.3 mm, 28.7 ± 9 mm, and 34.2 ± 9.7 mm. Conclusion: Our study has produced an assessment of glenoid bone stock for optimal positioning of the glenoid implant but also to obtain a reference to determine the ideal location of the humeral component in the case of proximal humerus fracture. PMID:27716461

  14. The relationship between organ dose and patient size in tube current modulated adult thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Khatonabadi, Maryam; Zhang, Di; Yang, Jeffrey; DeMarco, John J.; Cagnon, Chris C.; McNitt-Gray, Michael F.

    2012-03-01

    Recently published AAPM Task Group 204 developed conversion coefficients that use scanner reported CTDIvol to estimate dose to the center of patient undergoing fixed tube current body exam. However, most performed CT exams use TCM to reduce dose to patients. Therefore, the purpose of this study was to investigate the correlation between organ dose and a variety of patient size metrics in adult chest CT scans that use tube current modulation (TCM). Monte Carlo simulations were performed for 32 voxelized models with contoured lungs and glandular breasts tissue, consisting of females and males. These simulations made use of patient's actual TCM data to estimate organ dose. Using image data, different size metrics were calculated, these measurements were all performed on one slice, at the level of patient's nipple. Estimated doses were normalized by scanner-reported CTDIvol and plotted versus different metrics. CTDIvol values were plotted versus different metrics to look at scanner's output versus size. The metrics performed similarly in terms of correlating with organ dose. Looking at each gender separately, for male models normalized lung dose showed a better linear correlation (r2=0.91) with effective diameter, while female models showed higher correlation (r2=0.59) with the anterior-posterior measurement. There was essentially no correlation observed between size and CTDIvol-normalized breast dose. However, a linear relationship was observed between absolute breast dose and size. Dose to lungs and breasts were consistently higher in females with similar size as males which could be due to shape and composition differences between genders in the thoracic region.

  15. The evaluation and comparison of kidney length obtained from axial cuts in spiral CT scan with its true length

    PubMed Central

    Karami, Mehdi; Rahimi, Farshad; Tajadini, Mohammadhasan

    2015-01-01

    Background: Increased size of kidney is the main symptom of pyelonephritis and renal ischemia in children. Ultrasound and computed tomography (CT) scan methods are the imaging methods for evaluating the urogenital system. The aim of this study is to compare the kidney length obtained from spiral CT scan with the true length obtained from multi-slice CT. Materials and Methods: From 100 patients 200 kidneys were examined in Alzahra Hospital in 2012. Multi-slice CT was used to obtain coronal and sagittal cuts to find the length of kidneys. Results: The mean values of true size of axial sections of the right and left kidneys were 108.37 ± 12.3 mm and 109.74 ± 13.6 mm, respectively. The mean difference of axial sections’ lengths in the right and left kidneys was 1.37 ± 1.22 mm. The mean values of length in the spiral CT scan of the right and left kidneys were 98.61 ± 15.8 mm and 103.11 ± 15.9 mm, respectively. The difference in the estimated size by multi-slice CT scan in oblique and axial images was significant (9.77 ± 1.19 mm and 6.63 ± 0.8 mm for the right and left kidneys, respectively (P < 0.001). Conclusion: The average size of both kidneys determined in axial images was smaller than the actual size. The estimation of kidney size in axial images is not reliable, and to obtain the actual size, it is required to have the coronal and sagittal cuts with proper quality, which could be achieved by multi-slice method. PMID:25709984

  16. SU-E-J-111: The Contouring Error of the Parotids Based On the CT and MRI Images in Radiotherapy Planning for Nasopharyngeal Carcinoma

    SciTech Connect

    Gong, G; Liu, C

    2014-06-01

    Purpose: To analyze the variation of sketching the parotid for patients with nasopharyngeal carcinoma who underwent radiotherapy based on computed tomography (CT) and magnetic resonance(MR) images. Methods: 41 nasopharyngeal cancer patients were randomly selected. Each patient underwent MR and CT scanning. The Gross Tumor Volume and Organs at risk were contoured on both contrasted CT and T1-MR images. For each patient, one radiotherapist sketched the parotid on CT and MR images for 10 times, and 10 different radiotherapists were asked to sketching the parotid on CT and MR images only one time. The inter- and intra-observers volumes and outline variations were compared. Results: The volumes of parotid contoured by inter-observer on CT and MR images were 34.6±12.1cm{sup 3}(left),34.3±9.0cm{sup 3}(right) and 24.6±7.6cm{sup 3}(L),23.2±8.1cm{sup 3}(R); In the same way, for intra-observer on CT and MR images the volumes were 28.2±7.6cm{sup 3}(L),29.4±9.4cm{sup 3}(R) and 24.4±7.6cm{sup 3}(L),22.5±7.4cm{sup 3}(R), respectively. The variable ratios of volume on MR images were 4.7±0.7%(L),5.0±0.6%(R) for inter-observer and 2.3±0.4%(L),2.1±0.7%(R) for intra-observer. Similarly, The inter- and intra-observer ratios for contouring on CT images reached 18.0±4.8%(L),17.4±4.6%(R) and 6.3±1.5%(L),6.8±1.5%(R), respectively. Conclusion: Contouring the parotids on MR images was more accurate and reproducible than that on CT images.

  17. 4D CT amplitude binning for the generation of a time-averaged 3D mid-position CT scan.

    PubMed

    Kruis, Matthijs F; van de Kamer, Jeroen B; Belderbos, José S A; Sonke, Jan-Jakob; van Herk, Marcel

    2014-09-21

    The purpose of this study was to develop a method to use amplitude binned 4D-CT (A-4D-CT) data for the construction of mid-position CT data and to compare the results with data created from phase-binned 4D-CT (P-4D-CT) data. For the latter purpose we have developed two measures which describe the regularity of the 4D data and we have tried to correlate these measures with the regularity of the external respiration signal. 4D-CT data was acquired for 27 patients on a combined PET-CT scanner. The 4D data were reconstructed twice, using phase and amplitude binning. The 4D frames of each dataset were registered using a quadrature-based optical flow method. After registration the deformation vector field was repositioned to the mid-position. Since amplitude-binned 4D data does not provide temporal information, we corrected the mid-position for the occupancy of the bins. We quantified the differences between the two mid-position datasets in terms of tumour offset and amplitude differences. Furthermore, we measured the standard deviation of the image intensity over the respiration after registration (σregistration) and the regularity of the deformation vector field (Delta J) to quantify the quality of the 4D-CT data. These measures were correlated to the regularity of the external respiration signal (σsignal).The two irregularity measures, Delta J and σregistration, were dependent on each other (p<0.0001, R2=0.80 for P-4D-CT, R2=0.74 for A-4D-CT). For all datasets amplitude binning resulted in lower Delta J and σregistration and large decreases led to visible quality improvements in the mid-position data. The quantity of artefact decrease was correlated to the irregularity of the external respiratory signal.The average tumour offset between the phase and amplitude binned mid-position without occupancy correction was 0.42 mm in the caudal direction (10.6% of the amplitude). After correction this was reduced to 0.16 mm in caudal direction (4.1% of the amplitude

  18. Computer-aided detection (CAD) of hepatocellular carcinoma on multiphase CT images

    NASA Astrophysics Data System (ADS)

    Tajima, Tetsuji; Zhang, Xuejun; Kitagawa, Teruhiko; Kanematsu, Masayuki; Zhou, Xiangrong; Hara, Takeshi; Fujita, Hiroshi; Yokoyama, Ryujiro; Kondo, Hiroshi; Hoshi, Hiroaki; Nawano, Shigeru; Shinozaki, Kenji

    2007-03-01

    Primary malignant liver tumor, including hepatocellular carcinoma (HCC), caused 1.25 million deaths per year worldwide. Multiphase CT images offer clinicians important information about hepatic cancer. The presence of HCC is indicated by high-intensity regions in arterial phase images and low-intensity regions in equilibrium phase images following enhancement with contrast material. We propose an automatic method for detecting HCC based on edge detection and subtraction processing. Within a liver area segmented according to our scheme, black regions are selected by subtracting the equilibrium phase images to the corresponding registrated arterial phase images. From these black regions, the HCC candidates are extracted as the areas without edges by using Sobel and LoG edge detection filters. The false-positive (FP) candidates are eliminated by using six features extracted from the cancer and liver regions. Other FPs are further eliminated by opening processing. Finally, an expansion process is applied to acquire the 3D shape of the HCC. The cases used in this experiment were from the CT images of 44 patients, which included 44 HCCs. We extracted 97.7% (43/44) HCCs successfully by our proposed method, with an average number of 2.1 FPs per case. The result demonstrates that our edge-detection-based method is effective in locating the cancer region by using the information obtained from different phase images.

  19. Automatic segmentation and identification of solitary pulmonary nodules on follow-up CT scans based on local intensity structure analysis and non-rigid image registration

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Naito, Hideto; Nakamura, Yoshihiko; Kitasaka, Takayuki; Rueckert, Daniel; Honma, Hirotoshi; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Mori, Kensaku

    2011-03-01

    This paper presents a novel method that can automatically segment solitary pulmonary nodule (SPN) and match such segmented SPNs on follow-up thoracic CT scans. Due to the clinical importance, a physician needs to find SPNs on chest CT and observe its progress over time in order to diagnose whether it is benign or malignant, or to observe the effect of chemotherapy for malignant ones using follow-up data. However, the enormous amount of CT images makes large burden tasks to a physician. In order to lighten this burden, we developed a method for automatic segmentation and assisting observation of SPNs in follow-up CT scans. The SPNs on input 3D thoracic CT scan are segmented based on local intensity structure analysis and the information of pulmonary blood vessels. To compensate lung deformation, we co-register follow-up CT scans based on an affine and a non-rigid registration. Finally, the matches of detected nodules are found from registered CT scans based on a similarity measurement calculation. We applied these methods to three patients including 14 thoracic CT scans. Our segmentation method detected 96.7% of SPNs from the whole images, and the nodule matching method found 83.3% correspondences from segmented SPNs. The results also show our matching method is robust to the growth of SPN, including integration/separation and appearance/disappearance. These confirmed our method is feasible for segmenting and identifying SPNs on follow-up CT scans.

  20. Comparing the brain CT scan interpretation of emergency medicine team with radiologists' report and its impact on patients' outcome.

    PubMed

    Talebian, Mohammad-Taghi; Kavandi, Elahe; Farahmand, Shervin; Shahlafar, Neda; Arbab, Mona; Seyedhosseini-Davarani, Seyedhossein; Nejati, Amir; Bagheri-Hariri, Shahram

    2015-06-01

    Requesting non-enhanced brain CT scans for trauma and non-trauma patients in ER is very common. In this study, the impact of incorrect brain CT scan interpretations by emergency medicine team on patients' primary and secondary outcome was evaluated in the setting where neuroradiologist reports are not always available. During a 3-month period, 450 patients were enrolled and followed for 28 days. All CT scans were interpreted by the emergency medicine team, and the patients were managed accordingly. Neuroradiologists' reports were considered as gold standard, and the patients were then grouped into the agreement or disagreement group. A panel of experts further evaluated the disagreement group and placed them in clinically significant and insignificant. The agreement rate between emergency medicine team and neuroradiologists was 86.4 %. The inter-rater reliability between emergency team and neuroradiologists was substantial (kappa = 0.68) and statistically significant (p < 0.0001). Only five patients did not receive the necessary management, and among them, only one patient died, and 12 patients received unnecessary management including repeated CT scan, brain MRI, and lumbar puncture. Forty-one patients were managed clinically appropriate in spite of misinterpretation. A 28-day follow-up showed a mortality rate of 0.2 %; however, expert panel believed the death of this patient was not related to the CT scan misinterpretation. We conclude that although the disagreement rate in this study was 13.6 %, primary and secondary outcomes were not clinically jeopardized according to the expert panel idea and 28-day follow-up results.

  1. Effect of deformable registration on the dose calculated in radiation therapy planning CT scans of lung cancer patients

    SciTech Connect

    Cunliffe, Alexandra R.; Armato, Samuel G.; White, Bradley; Justusson, Julia; Contee, Clay; Malik, Renuka; Al-Hallaq, Hania A.

    2015-01-15

    Purpose: To characterize the effects of deformable image registration of serial computed tomography (CT) scans on the radiation dose calculated from a treatment planning scan. Methods: Eighteen patients who received curative doses (≥60 Gy, 2 Gy/fraction) of photon radiation therapy for lung cancer treatment were retrospectively identified. For each patient, a diagnostic-quality pretherapy (4–75 days) CT scan and a treatment planning scan with an associated dose map were collected. To establish correspondence between scan pairs, a researcher manually identified anatomically corresponding landmark point pairs between the two scans. Pretherapy scans then were coregistered with planning scans (and associated dose maps) using the demons deformable registration algorithm and two variants of the Fraunhofer MEVIS algorithm (“Fast” and “EMPIRE10”). Landmark points in each pretherapy scan were automatically mapped to the planning scan using the displacement vector field output from each of the three algorithms. The Euclidean distance between manually and automatically mapped landmark points (d{sub E}) and the absolute difference in planned dose (|ΔD|) were calculated. Using regression modeling, |ΔD| was modeled as a function of d{sub E}, dose (D), dose standard deviation (SD{sub dose}) in an eight-pixel neighborhood, and the registration algorithm used. Results: Over 1400 landmark point pairs were identified, with 58–93 (median: 84) points identified per patient. Average |ΔD| across patients was 3.5 Gy (range: 0.9–10.6 Gy). Registration accuracy was highest using the Fraunhofer MEVIS EMPIRE10 algorithm, with an average d{sub E} across patients of 5.2 mm (compared with >7 mm for the other two algorithms). Consequently, average |ΔD| was also lowest using the Fraunhofer MEVIS EMPIRE10 algorithm. |ΔD| increased significantly as a function of d{sub E} (0.42 Gy/mm), D (0.05 Gy/Gy), SD{sub dose} (1.4 Gy/Gy), and the algorithm used (≤1 Gy). Conclusions: An

  2. Response Assessment and Prediction in Esophageal Cancer Patients via F-18 FDG PET/CT Scans

    NASA Astrophysics Data System (ADS)

    Higgins, Kyle J.

    Purpose: The purpose of this study is to utilize F-18 FDG PET/CT scans to determine an indicator for the response of esophageal cancer patients during radiation therapy. There is a need for such an indicator since local failures are quite common in esophageal cancer patients despite modern treatment techniques. If an indicator is found, a patient's treatment strategy may be altered to possibly improve the outcome. This is investigated with various standard uptake volume (SUV) metrics along with image texture features. The metrics and features showing the most promise and indicating response are used in logistic regression analysis to find an equation for the prediction of response. Materials and Methods: 28 patients underwent F-18 FDG PET/CT scans prior to the start of radiation therapy (RT). A second PET/CT scan was administered following the delivery of ~32 Gray (Gy) of dose. A physician contoured gross tumor volume (GTV) was used to delineate a PET based GTV (GTV-pre-PET) based on a threshold of >40% and >20% of the maximum SUV value in the GTV. Deformable registration was used in VelocityAI software to register the pre-treatment and intra-treatment CT scans so that the GTV-pre-PET contours could be transferred from the pre to intra scans (GTV-intra-PET). The fractional decrease in the maximum, mean, volume to the highest intensity 10%-90%, and combination SUV metrics of the significant previous SUV metrics were compared to post-treatment pathologic response for an indication of response. Next for the >40% threshold, texture features based on a neighborhood gray-tone dimension matrix (NGTDM) were analyzed. The fractional decrease in coarseness, contrast, busyness, complexity, and texture strength were compared to the pathologic response of the patients. From these previous two types of analysis, SUV and texture features, the two most significant results were used in logistic regression analysis to find an equation to predict the probability of a non

  3. Photodynamic therapy light dose analysis of a patient based upon arterial and venous contrast CT scan information

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Davis, Scott C.; Dehghani, Hamid; Huggett, Matthew; Hasan, Tayyaba; Pereira, Stephen P.; Pogue, Brian W.

    2013-03-01

    The goal of this work was to determine the light dose required to induce necrosis in verteporfin-based photodynamic therapy, in the VERTPAC-1 trial. Patient CT scans were obtained of the abdomen, including the entire treatment zone of pancreas and surrounding tissues, before and after treatment, as well as fast scans during needle placement. These scans were used to estimate arterial and venous blood content, and provide structural information of the pancreas and nearby blood vessels. Using NIRFAST, a finite-element based package for modeling diffuse near-infrared light transport in tissue, simulations were run to create maps of light fluence within the pancreas. These maps provided visualizations of light dose overlaid on the original CT scans, and were used to estimate light dose at the boundary of the zone of necrosis, as observed in follow up treatment outcome CT scans. The aim of these simulation studies was to assist pre-treatment planning by informing the light treatment parameters. This paper presents a case study of the process used on a single patient.

  4. Teng-Long-Bu-Zhong-Tang, a Chinese herbal formula, enhances anticancer effects of 5 - Fluorouracil in CT26 colon carcinoma

    PubMed Central

    2013-01-01

    Background Colorectal cancer remains one of the leading causes of cancer death worldwide. Traditional Chinese Medicine (TCM) has played a positive role in colorectal cancer treatment. There is a great need to establish effective herbal formula for colorectal cancer treatment. Based on TCM principles and clinical practices, we have established an eight herbs composed formula for colorectal cancer treatment, which is Teng-Long-Bu-Zhong-Tang (TLBZT). We have demonstrated the anticancer effects of TLBZT against colorectal carcinoma in vitro. In present study, we evaluated the anticancer potential of TLBZT, used alone or in combination with low dose of 5-Fluorouracil (5-Fu), in CT26 colon carcinoma in vivo. Methods CT26 colon carcinoma was established in BALB/c mice and treated with TLBZT, 5-Fu, or TLBZT plus 5-Fu. The tumor volumes were observed. Apoptosis was detected by TUNEL assay. Caspases activities were detected by colorimetric assay. Cell senescence was indentified by senescence β-galactosidase staining. Gene expression and angiogenesis was observed by immunohistochemistry or western blot. Results TLBZT significantly inhibited CT26 colon carcinoma growth. TLBZT elicited apoptosis in CT26 colon carcinoma, accompanied by Caspase-3, 8, and 9 activation and PARP cleavage, and downregulation of XIAP and Survivin. TLBZT also induced cell senescence in CT26 colon carcinoma, with concomitant upregulation of p16 and p21 and downregulation of RB phosphorylation. In addition, angiogenesis and VEGF expression in CT26 colon carcinoma was significantly inhibited by TLBZT treatment. Furthermore, TLBZT significantly enhanced anticancer effects of 5-Fu in CT26 colon carcinoma. Conclusions TLBZT exhibited significantly anticancer effect, and enhanced the effects of 5-Fu in CT26 colon carcinoma, which may correlate with induction of apoptosis and cell senescence, and angiogenesis inhibition. The present study provides new insight into TCM approaches for colon cancer treatment

  5. Impact of number of repeated scans on model observer performance for a low-contrast detection task in CT

    NASA Astrophysics Data System (ADS)

    Ma, Chi; Yu, Lifeng; Chen, Baiyu; Vrieze, Thomas; Favazza, Christopher; Leng, Shuai; McCollough, Cynthia

    2015-03-01

    In previous investigations on CT image quality, channelized Hotelling observer (CHO) models have been shown to well represent human observer performance in several phantom-based detection/discrimination tasks. In these studies, a large number of independent images was necessary to estimate the expectation images and covariance matrices for each test condition. The purpose of this study is to investigate how the number of repeated scans affects the precision and accuracy of the CHO's performance in a signal-known-exactly detection task. A phantom containing 21 low-contrast objects (3 contrast levels and 7 sizes) was scanned with a 128-slice CT scanner at three dose levels. For each dose level, 100 independent images were acquired for each test condition. All images were reconstructed using filtered-backprojection (FBP) and a commercial iterative reconstruction algorithm. For each combination of dose level and reconstruction method, the low-contrast detectability, quantified with the area under receiver operating characteristic curve (Az), was calculated using a previously validated CHO model. To determine the dependency of CHO performance on the number of repeated scans, the Az value was calculated for different number of channel filters, for each object size and contrast, and for different dose/reconstruction settings using all 100 repeated scans. The Az values were also calculated using randomly selected subsets of the scans (from 10 to 90 scans with an increment of 10 scans). Using the Az from the 100 scans as the reference, the accuracy of Az values calculated from a fewer number of scans was determined and the minimal number of scans was subsequently derived. For the studied signal-known-exactly detection task, results demonstrated that, the minimal number of scans depends on dose level, object size and contrast level, and channel filters.

  6. A study on the change in image quality before and after an attenuation correction with the use of a CT image in a SPECT/CT scan

    NASA Astrophysics Data System (ADS)

    Park, Yong-Soon; Kim, Woo-Hyun; Shim, Dong-Oh; Kim, Ho-Sung; Chung, Woon-Kwan; Cho, Jae-Hwan

    2012-12-01

    This study compared the SPECT (single-photon emission computed tomography) images before and after applying an attenuation correction by using the CT (computed tomography) image in a SPECT/CT scan and examined depending of the change in image quality on the CT dose. A flangeless Esser PET (positron emission tomography) Phantom was used to evaluate the image quality for the Precedence 16 SPECT/CT system manufactured by Philips. The experimental method was to obtain a SPECT image and a CT image of a flangeless Esser PET Phantom to acquire an attenuation-corrected SPECT image. A ROI (region of interest) was then set up at a hot spot of the acquired image to measure the SNR (signal to noise ratio) and the FWHM (full width at half maximum) and to compare the image quality with that of an unattenuation-corrected SPECT image. To evaluate the quality of a SPECT image, we set the ROI as a cylinder diameter (25, 16, 12, and 8 mm) and the BKG (background) radioactivity of the phantom images was obtained when each CT condition was changed. Subsequently, the counts were compared to measure the SNR. The FWHM of the smallest cylinder (8 mm) was measured to compare the image quality. A comparison of the SPECT images with and without attenuation correction revealed 5.01-fold, 4.77 fold, 4.43-fold, 4.38-fold, and 5.13-fold differences in SNR for the 25-mm cylinder, 16-mm cylinder, 12-mm cylinder, 8-mm cylinder, and BKG, respectively. In the phantom image obtained when the CT dose was changed, the FWHM of the 8-mm cylinder showed almost no difference under each condition regardless of the changes in kVp and mAs.

  7. Percutaneous Bone Biopsies: Comparison between Flat-Panel Cone-Beam CT and CT-Scan Guidance

    SciTech Connect

    Tselikas, Lambros Joskin, Julien; Roquet, Florian; Farouil, Geoffroy; Dreuil, Serge; Hakimé, Antoine Teriitehau, Christophe; Auperin, Anne; Baere, Thierry de Deschamps, Frederic

    2015-02-15

    PurposeThis study was designed to compare the accuracy of targeting and the radiation dose of bone biopsies performed either under fluoroscopic guidance using a cone-beam CT with real-time 3D image fusion software (FP-CBCT-guidance) or under conventional computed tomography guidance (CT-guidance).MethodsSixty-eight consecutive patients with a bone lesion were prospectively included. The bone biopsies were scheduled under FP-CBCT-guidance or under CT-guidance according to operating room availability. Thirty-four patients underwent a bone biopsy under FP-CBCT and 34 under CT-guidance. We prospectively compared the two guidance modalities for their technical success, accuracy, puncture time, and pathological success rate. Patient and physician radiation doses also were compared.ResultsAll biopsies were technically successful, with both guidance modalities. Accuracy was significantly better using FP-CBCT-guidance (3 and 5 mm respectively: p = 0.003). There was no significant difference in puncture time (32 and 31 min respectively, p = 0.51) nor in pathological results (88 and 88 % of pathological success respectively, p = 1). Patient radiation doses were significantly lower with FP-CBCT (45 vs. 136 mSv, p < 0.0001). The percentage of operators who received a dose higher than 0.001 mSv (dosimeter detection dose threshold) was lower with FP-CBCT than CT-guidance (27 vs. 59 %, p = 0.01).ConclusionsFP-CBCT-guidance for bone biopsy is accurate and reduces patient and operator radiation doses compared with CT-guidance.

  8. Sliding slice: A novel approach for high accuracy and automatic 3D localization of seeds from CT scans

    SciTech Connect

    Tubic, Dragan; Beaulieu, Luc

    2005-01-01

    We present a conceptually novel principle for 3D reconstruction of prostate seed implants. Unlike existing methods for implant reconstruction, the proposed algorithm uses raw CT data (sinograms) instead of reconstructed CT slices. Using raw CT data solves several inevitable problems related to the reconstruction from CT slices. First, the sinograms are not affected by reconstruction artifacts in the presence of metallic objects and seeds in the patient body. Second, the scanning axis is not undersampled as in the case of CT slices; as a matter of fact the scanning axis is the most densely sampled and each seed is typically represented by several hundred samples. Moreover, the shape of a single seed in a sinogram can be modeled exactly, thus facilitating the detection. All this allows very accurate 3D reconstruction of both position and the orientation of the seeds. Preliminary results indicate that the seed position can be estimated with 0.15 mm accuracy (average), while the orientation estimate accuracy is within 3 deg. on average. Although the main contribution of the paper is to present a new principle of reconstruction, a preliminary implementation is also presented as a proof of concept. The implemented algorithm has been tested on a phantom and the obtained results are presented to validate the proposed approach.

  9. Sex determination from scapular length measurements by CT scans images in a Caucasian population.

    PubMed

    Giurazza, F; Schena, E; Del Vescovo, R; Cazzato, R L; Mortato, L; Saccomandi, P; Paternostro, F; Onofri, L; Zobel, B Beomonte

    2013-01-01

    Together with race, stature and age, sex is a main component of the biological identity. Thanks to its proportional correlation with parts of the human body, sex can be evaluated form the skeleton. The most accurate approach to determine sex by bone size is based on os coxae or skull. After natural disaster their presence can never be guaranteed, therefore the development of methods of sex determination using other skeletal elements can result crucial. Herein, sexual dimorphism in the human scapula is used to develop a two-variable discriminant function for sex estimation. We have enrolled 100 males and 100 females who underwent thoracic CT scan evaluation and we have estimated two scapular diameters. The estimation has been carried out by analyzing images of the scapulae of each patient after three dimensional post-processing reconstructions. The two-variable function allows to obtain an overall accuracy of 88% on the calibration sample. Furthermore, we have employed the mentioned function on a collection of 10 individual test sample from the collection of the "Museo di Anatomia Umana di Firenze" of the Università degli Studi di Firenze; sex has been correctly predicted on 9 skeletons.

  10. 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. PMID:26028278

  11. Scatter correction method for cone-beam CT based on interlacing-slit scan

    NASA Astrophysics Data System (ADS)

    Huang, Kui-Dong; Zhang, Hua; Shi, Yi-Kai; Zhang, Liang; Xu, Zhe

    2014-09-01

    Cone-beam computed tomography (CBCT) has the notable features of high efficiency and high precision, and is widely used in areas such as medical imaging and industrial non-destructive testing. However, the presence of the ray scatter reduces the quality of CT images. By referencing the slit collimation approach, a scatter correction method for CBCT based on the interlacing-slit scan is proposed. Firstly, according to the characteristics of CBCT imaging, a scatter suppression plate with interlacing slits is designed and fabricated. Then the imaging of the scatter suppression plate is analyzed, and a scatter correction calculation method for CBCT based on the image fusion is proposed, which can splice out a complete set of scatter suppression projection images according to the interlacing-slit projection images of the left and the right imaging regions in the scatter suppression plate, and simultaneously complete the scatter correction within the flat panel detector (FPD). Finally, the overall process of scatter suppression and correction is provided. The experimental results show that this method can significantly improve the clarity of the slice images and achieve a good scatter correction.

  12. The First Ant-Termite Syninclusion in Amber with CT-Scan Analysis of Taphonomy

    PubMed Central

    Coty, David; Aria, Cédric; Garrouste, Romain; Wils, Patricia; Legendre, Frédéric; Nel, André

    2014-01-01

    We describe here a co-occurrence (i.e. a syninclusion) of ants and termites in a piece of Mexican amber (Totolapa deposit, Chiapas), whose importance is two-fold. First, this finding suggests at least a middle Miocene antiquity for the modern, though poorly documented, relationship between Azteca ants and Nasutitermes termites. Second, the presence of a Neivamyrmex army ant documents an in situ raiding behaviour of the same age and within the same community, confirmed by the fact that the army ant is holding one of the termite worker between its mandibles and by the presence of a termite with bitten abdomen. In addition, we present how CT-scan imaging can be an efficient tool to describe the topology of resin flows within amber pieces, and to point out the different states of preservation of the embedded insects. This can help achieving a better understanding of taphonomical processes, and tests ethological and ecological hypotheses in such complex syninclusions. PMID:25140873

  13. Pleural plaque profiles on the chest radiographs and CT scans of asbestos-exposed Japanese construction workers.

    PubMed

    Elshazley, Momen; Shibata, Eiji; Hisanaga, Naomi; Ichihara, Gaku; Ewis, Ashraf A; Kamijima, Michihiro; Ichihara, Sahoko; Sakai, Kiyoshi; Sato, Mitsuo; Kondo, Masashi; Hasegawa, Yoshinori

    2011-01-01

    Pleural plaques are asymptomatic focal thickenings of the pleura and considered the hallmark of asbestos exposure. However, it is often difficult to detect pleural plaques on chest x-rays (CXR). In a retrospective study, using chest CT scans of 140 Japanese asbestos-exposed construction workers who have probable or definite findings of pleural plaque on CXR; firstly, we proposed plaque morphology-based classification for CXR findings, and then we examined if those classified findings could be confirmed as pleural plaques on CT scans. Our morphology-based classification of pleural plaque findings included nine types. The percentages of confirmed pleural plaques on CT scans by type (number of confirmed pleural plaque on CT/number of observed on CXR) were 93% (40/43) for straight, 89% (56/63) for diamond, 88% (7/8) for double, 83% (19/23) for tapered medially, 80% (20/25) for parallel, 77% (23/30) for crescent, 79% (11/14) for tenting, 72% (18/25) for tapered-laterally (long type), and 0% (0/9) for tapered-laterally (short type). When added to the ILO classification, morphology-based classification of CXR pleural plaque findings makes its detection easier and hence chest radiograph continues to be a suitable tool for screening asbestos-related pleural plaques based on its simplicity, low radiation exposure, wide availability and cost-effectiveness. PMID:21828957

  14. Automatic identification of IASLC-defined mediastinal lymph node stations on CT scans using multi-atlas organ segmentation

    NASA Astrophysics Data System (ADS)

    Hoffman, Joanne; Liu, Jiamin; Turkbey, Evrim; Kim, Lauren; Summers, Ronald M.

    2015-03-01

    Station-labeling of mediastinal lymph nodes is typically performed to identify the location of enlarged nodes for cancer staging. Stations are usually assigned in clinical radiology practice manually by qualitative visual assessment on CT scans, which is time consuming and highly variable. In this paper, we developed a method that automatically recognizes the lymph node stations in thoracic CT scans based on the anatomical organs in the mediastinum. First, the trachea, lungs, and spines are automatically segmented to locate the mediastinum region. Then, eight more anatomical organs are simultaneously identified by multi-atlas segmentation. Finally, with the segmentation of those anatomical organs, we convert the text definitions of the International Association for the Study of Lung Cancer (IASLC) lymph node map into patient-specific color-coded CT image maps. Thus, a lymph node station is automatically assigned to each lymph node. We applied this system to CT scans of 86 patients with 336 mediastinal lymph nodes measuring equal or greater than 10 mm. 84.8% of mediastinal lymph nodes were correctly mapped to their stations.

  15. Multiparametric Evaluation of Head and Neck Squamous Cell Carcinoma Using a Single-Source Dual-Energy CT with Fast kVp Switching: State of the Art

    PubMed Central

    Lam, Stephanie; Gupta, Rajiv; Kelly, Hillary; Curtin, Hugh D.; Forghani, Reza

    2015-01-01

    There is an increasing body of evidence establishing the advantages of dual-energy CT (DECT) for evaluation of head and neck squamous cell carcinoma (HNSCC). Focusing on a single-source DECT system with fast kVp switching, we will review the principles behind DECT and associated post-processing steps that make this technology especially suitable for HNSCC evaluation and staging. The article will review current applications of DECT for evaluation of HNSCC including use of different reconstructions to improve tumor conspicuity, tumor-normal soft tissue interface, accuracy of invasion of critical structures such as thyroid cartilage, and reduce dental artifact. We will provide a practical approach for DECT implementation into routine clinical use and a multi-parametric approach for scan interpretation based on the experience at our institution. The article will conclude with a brief overview of potential future applications of the technique. PMID:26561835

  16. An Indirect Method to Measure Abutment Screw Preload: A Pilot Study Based on Micro-CT Scanning.

    PubMed

    Rezende, Carlos Eduardo E; Griggs, Jason Alan; Duan, Yuanyuan; Mushashe, Amanda M; Nolasco, Gisele Maria Correr; Borges, Ana Flávia Sanches; Rubo, José Henrique

    2015-01-01

    This study aimed to measure the preload in different implant platform geometries based on micro-CT images. External hexagon (EH) implants and Morse Tapered (MT) implants (n=5) were used for the preload measurement. The abutment screws were scanned in micro-CT to obtain their virtual models, which were used to record their initial length. The abutments were screwed on the implant with a 20 Ncm torque and the set composed by implant, abutment screw and abutment were taken to the micro-CT scanner to obtain virtual slices of the specimens. These slices allowed the measurement of screw lengths after torque application and based on the screw elongation. Preload values were calculated using the Hooke's Law. The preloads of both groups were compared by independent t-test. Removal torque of each specimen was recorded. To evaluate the accuracy of the micro-CT technique, three rods with known lengths were scanned and the length of their virtual model was measured and compared with the original length. One rod was scanned four times to evaluate the measuring method variation. There was no difference between groups for preload (EH = 461.6 N and MT = 477.4 N), but the EH group showed higher removal torque values (13.8 ± 4.7 against 8.2 ± 3.6 N cm for MT group). The micro-CT technique showed a variability of 0.053% and repeatability showed an error of 0.23 to 0.28%. Within the limitations of this study, there was no difference between external hexagon and Morse taper for preload. The method using micro-CT may be considered for preload calculation.

  17. The Value of Restaging With Chest and Abdominal CT/MRI Scan After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

    PubMed Central

    Liu, Guo-Chen; Zhang, Xu; Xie, E.; An, Xin; Cai, Pei-Qiang; Zhu, Ying; Tang, Jing-Hua; Kong, Ling-Heng; Lin, Jun-Zhong; Pan, Zhi-Zhong; Ding, Pei-Rong

    2015-01-01

    Abstract Little was known with regard to the value of preoperative systemic restaging for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). This study was designed to evaluate the role of chest and abdominal computed tomography (CT) scan or magnetic resonance imaging (MRI) on preoperative restaging in LARC after neoadjuvant CRT and to assess the impact on treatment strategy. Between January 2007 and April 2013, 386 newly diagnosed consecutive patients with LARC who underwent neoadjuvant CRT and received restaging with chest and abdominal CT/MRI scan were included. Imaging results before and after CRT were analyzed. Twelve patients (3.1%) (6 liver lesions, 2 peritoneal lesions, 2 distant lymph node lesions, 1 lung lesions, 1 liver and lung lesions) were diagnosed as suspicious metastases on the restaging scan after radiotherapy. Seven patients (1.8%) were confirmed as metastases by pathology or long-term follow-up. The treatment strategy was changed in 5 of the 12 patients as a result of restaging CT/MRI findings. Another 10 patients (2.6%) who present with normal restaging imaging findings were diagnosed as metastases intra-operatively. The sensitivity, specificity accuracy, negative predictive value, and positive predictive values of restaging CT/MRI was 41.4%, 98.6%, 58.3%, and 97.3%, respectively. The low incidence of metastases and minimal consequences for the treatment plan question the clinical value of routine restaging of chest and abdomen after neoadjuvant CRT. Based on this study, a routine restaging CT/MRI of chest and abdomen in patients with rectal cancer after neoadjuvant CRT is not advocated, carcino-embryonic antigen (CEA) -guided CT/MRI restaging might be an alternative. PMID:26632714

  18. Comparison of Two Deformable Registration Algorithms in the Presence of Radiologic Change Between Serial Lung CT Scans.

    PubMed

    Cunliffe, Alexandra R; White, Bradley; Justusson, Julia; Straus, Christopher; Malik, Renuka; Al-Hallaq, Hania A; Armato, Samuel G

    2015-12-01

    We evaluated the image registration accuracy achieved using two deformable registration algorithms when radiation-induced normal tissue changes were present between serial computed tomography (CT) scans. Two thoracic CT scans were collected for each of 24 patients who underwent radiation therapy (RT) treatment for lung cancer, eight of whom experienced radiologically evident normal tissue damage between pre- and post-RT scan acquisition. For each patient, 100 landmark point pairs were manually placed in anatomically corresponding locations between each pre- and post-RT scan. Each post-RT scan was then registered to the pre-RT scan using (1) the Plastimatch demons algorithm and (2) the Fraunhofer MEVIS algorithm. The registration accuracy for each scan pair was evaluated by comparing the distance between landmark points that were manually placed in the post-RT scans and points that were automatically mapped from pre- to post-RT scans using the displacement vector fields output by the two registration algorithms. For both algorithms, the registration accuracy was significantly decreased when normal tissue damage was present in the post-RT scan. Using the Plastimatch algorithm, registration accuracy was 2.4 mm, on average, in the absence of radiation-induced damage and 4.6 mm, on average, in the presence of damage. When the Fraunhofer MEVIS algorithm was instead used, registration errors decreased to 1.3 mm, on average, in the absence of damage and 2.5 mm, on average, when damage was present. This work demonstrated that the presence of lung tissue changes introduced following RT treatment for lung cancer can significantly decrease the registration accuracy achieved using deformable registration.

  19. Comparison of Two Deformable Registration Algorithms in the Presence of Radiologic Change Between Serial Lung CT Scans.

    PubMed

    Cunliffe, Alexandra R; White, Bradley; Justusson, Julia; Straus, Christopher; Malik, Renuka; Al-Hallaq, Hania A; Armato, Samuel G

    2015-12-01

    We evaluated the image registration accuracy achieved using two deformable registration algorithms when radiation-induced normal tissue changes were present between serial computed tomography (CT) scans. Two thoracic CT scans were collected for each of 24 patients who underwent radiation therapy (RT) treatment for lung cancer, eight of whom experienced radiologically evident normal tissue damage between pre- and post-RT scan acquisition. For each patient, 100 landmark point pairs were manually placed in anatomically corresponding locations between each pre- and post-RT scan. Each post-RT scan was then registered to the pre-RT scan using (1) the Plastimatch demons algorithm and (2) the Fraunhofer MEVIS algorithm. The registration accuracy for each scan pair was evaluated by comparing the distance between landmark points that were manually placed in the post-RT scans and points that were automatically mapped from pre- to post-RT scans using the displacement vector fields output by the two registration algorithms. For both algorithms, the registration accuracy was significantly decreased when normal tissue damage was present in the post-RT scan. Using the Plastimatch algorithm, registration accuracy was 2.4 mm, on average, in the absence of radiation-induced damage and 4.6 mm, on average, in the presence of damage. When the Fraunhofer MEVIS algorithm was instead used, registration errors decreased to 1.3 mm, on average, in the absence of damage and 2.5 mm, on average, when damage was present. This work demonstrated that the presence of lung tissue changes introduced following RT treatment for lung cancer can significantly decrease the registration accuracy achieved using deformable registration. PMID:25822396

  20. Is it practical and cost effective to detect differentiated thyroid carcinoma metastases by (18)F-FDG PET/CT, by (18)F-FDG SPET/CT or by (131)I SPET/CT?

    PubMed

    He, Xinjia; Wang, Xucai; Yu, Jinming; Ma, Chao

    2015-01-01

    Fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose positron emission tomography/computerized tomography ((18)F-FDG PET/CT) plays an important role in detecting differentiated thyroid carcinoma (DTC) metastases with elevated thyroglobulin (Tg) and negative radioiodine ((131)I) uptake. In conclusion, (18)F-FDG PET/CT may fail to detect all DTC metastases, while (131)I WBS combined with (131)I SPET/CT may be a better cheaper and diagnostic tool as suggested by the case we presented here. Positive metastases in both (131)I and (18)F-FDG SPET/CT may indicate worse prognosis. Future research may add more evidence as to which is the best diagnostic imaging modality and relate it to the molecular mechanism of the uptake of the radionuclide used.

  1. Assessment of the increased calcification of the jaw bone with CT-Scan after dental implant placement

    PubMed Central

    2011-01-01

    Purpose This study was performed to evaluate the changes of jaw bone density around the dental implant after placement using computed tomography scan (CT-Scan). Materials and Methods This retrospective study consisted of 30 patients who had lost 1 posterior tooth in maxilla or mandible and installed dental implant. The patients took CT-Scan before and after implant placement. Hounsfield Unit (HU) was measured around the implants and evaluated the difference of HU before and after implant installation. Results The mean HU of jaw bone was 542.436 HU and 764.9 HU before and after implant placement, respectively (p<0.05). The means HUs for male were 632.3 HU and 932.2 HU and those for female 478.2 HU and 645.5 HU before and after implant placement, respectively (p<0.05). Also, the jaw bone with lower density needed longer period for implant procedure and the increased change of HU of jaw bone was less in the cases which needed longer period for osseointegration. Conclusion CT-Scan could be used to assess the change of bone density around dental implants. Bone density around dental implant was increased after placement. The increased rate of bone density could be determined by the quality of jaw bone before implant placement. PMID:21977476

  2. Automatic intrinsic cardiac and respiratory gating from cone-beam CT scans of the thorax region

    NASA Astrophysics Data System (ADS)

    Hahn, Andreas; Sauppe, Sebastian; Lell, Michael; Kachelrieß, Marc

    2016-03-01

    We present a new algorithm that allows for raw data-based automated cardiac and respiratory intrinsic gating in cone-beam CT scans. It can be summarized in three steps: First, a median filter is applied to an initially reconstructed volume. The forward projection of this volume contains less motion information and is subtracted from the original projections. This results in new raw data that contain only moving and not static anatomy like bones, that would otherwise impede the cardiac or respiratory signal acquisition. All further steps are applied to these modified raw data. Second, the raw data are cropped to a region of interest (ROI). The ROI in the raw data is determined by the forward projection of a binary volume of interest (VOI) that includes the diaphragm for respiratory gating and most of the edge of the heart for cardiac gating. Third, the mean gray value in this ROI is calculated for every projection and the respiratory/cardiac signal is acquired using a bandpass filter. Steps two and three are carried out simultaneously for 64 or 1440 overlapping VOI inside the body for the respiratory or cardiac signal respectively. The signals acquired from each ROI are compared and the most consistent one is chosen as the desired cardiac or respiratory motion signal. Consistency is assessed by the standard deviation of the time between two maxima. The robustness and efficiency of the method is evaluated using simulated and measured patient data by computing the standard deviation of the mean signal difference between the ground truth and the intrinsic signal.

  3. SU-E-I-37: Eye Lens Dose Reduction From CT Scan Using Organ Based Tube Current Modulation

    SciTech Connect

    Liu, H; Liu, T; Xu, X; Wu, J; Zhuo, W

    2015-06-15

    Purpose: To investigate the eye lens dose reduction by CT scan with organ based tube current modulation (OBTCM) using GPU Monte Carlo code ARCHER-CT. Methods: 36 X-ray sources and bowtie filters were placed around the patient head with the projection angle interval of 10° for one rotation of CT scan, each projection was simulated respectively. The voxel eye models with high resolution(0.1mm*0.1mm*0.1mm) were used in the simulation and different tube voltage including 80kVp, 100kVp, 120kVp and 140kVp were taken into consideration. Results: The radiation doses to the eye lens increased with the tube voltage raised from 80kVp to 140kVp, and the dose results from 0° (AP) direction are much higher than those from 180° (PA) direction for all the 4 different tube voltage investigated. This 360° projection dose characteristic enables organ based TCM, which can reduce the eye lens dose by more than 55%. Conclusion: As the eye lens belongs to superficial tissues, its radiation dose to external exposure like CT is direction sensitive, and this characteristic feature makes organ based TCM to be an effective way to reduce the eye lens dose, so more clinical use of this technique were recommended. National Nature Science Foundation of China(No.11475047)

  4. Complementary role of CT and In-111 leukocyte scans in the diagnosis of infected hematoma and thrombosis

    SciTech Connect

    Kim, E.E.; Pjura, G.A.; Floyd, W.; Raval, B.; Sandler, C.; Gobuty, A.H.

    1984-01-01

    Patients with traumatic hematomas or those with indwelling catheters who subsequently develop fever and sepsis without clinical localizing signs to indicate an inflammatory focus can present a diagnostic dilemma. Early diagnosis of an infected hematoma or thrombus is important to optimal management. CT can provide, exquisite delineation of anatomy identifying and localizing a post-traumatic fluid collection but cannot reliably distinguish hematoma from abscess in all cases. A thrombus at a catheter tip may be too small to be resolved; when identified, the question of infection again remains. In-111 leukocyte scanning provides a method for identifying or ruling out infection in these situations. The authors performed In-111 leukocyte scans on 15 patients with indwelling catheters. Five of these patients were febrile with positive blood cultures. In-111 leukocyte scans showed positive findings in 8 patients: 5 showed surgically confirmed infected hematomas in the abdomen (3 in the pelvis, 1 in a kidney, 1 in the splenic bed), and 3 showed infected thrombosis in catheter tips. The authors conclude that CT scanning and In-111 leukocyte scanning play complementary roles in the evaluation of traumatic hematomas and thrombosis, the former providing precise anatomic delineation and the latter providing evidence of inflammation.

  5. Top-level design and pilot analysis of low-end CT scanners based on linear scanning for developing countries.

    PubMed

    Liu, Fenglin; Yu, Hengyong; Cong, Wenxiang; Wang, Ge

    2014-01-01

    The goal is to develop new architectures for computed tomography (CT) which are at an ultra-low-cost for developing countries, especially in rural areas. The proposed general scheme is inspired by the recently developed compressive sensing and interior tomography techniques, where the data acquisition system targets a region of interest (ROI) to acquire limited and truncated data. Similar to linear tomosynthesis, the source and detector are translated in opposite directions but in contrast to conventional tomosynthesis, our proposal is for either ROI reconstruction with one or more localized linear scans or global reconstruction by combining multiple ROI reconstructions. In other words, the popular slip ring is replaced by a translation based setup, and the instrumentation cost is reduced by a relaxation of the imaging speed requirement. The various translational scanning modes are theoretically analyzed, and the scanning parameters are optimized. The numerical simulation results from different numbers of linear scans confirm the feasibility of the proposed scheme, and suggest two preferred low-end systems for horizontal and vertical patient positions respectively. Ultra-low-cost x-ray CT is feasible with our proposed combination of linear scanning, compressive sensing, and interior tomography. The proposed architecture can be tailored into permanent, movable, or reconfigurable systems as desirable. Advanced image registration and spectral imaging features can be included as well.

  6. [A case of head injury accompanied by minute hemorrhage-like artifacts created by multislice CT scans].

    PubMed

    Yanagawa, Youichi; Sakamoto, Toshihisa; Okada, Yoshiaki

    2004-11-01

    We demonstrated a head injury case accompanied by multiple small high-density artifacts in the middle of the brain created by multislice CT scanning, due to the malfunction of a detector involved in reconstruction of the mid images. We named these objects high-density spot artifacts. The high-density spot artifacts resemble minute hemorrhages which appear as diffuse axonal injuries. Radiologists and neurosurgeons should be familiar with this the existence of artifact.

  7. Do physical examination and CT-scan measures of femoral neck anteversion and tibial torsion relate to each other?

    PubMed

    Sangeux, Morgan; Mahy, Jessica; Graham, H Kerr

    2014-01-01

    Informed clinical decision making for femoral and/or tibial de-rotation osteotomies requires accurate measurement of patient function through gait analysis and anatomy through physical examination of bony torsions. Validity of gait analysis has been extensively studied; however, controversy remains regarding the accuracy of physical examination measurements of femoral and tibial torsion. Comparison between CT-scans and physical examination measurements of femoral neck anteversion (FNA) and external tibial torsion (ETT) were retrospectively obtained for 98 (FNA) and 64 (ETT) patients who attended a tertiary hospital for instrumented gait analysis between 2007 and 2010. The physical examination methods studied for femoral neck anteversion were the trochanteric prominence angle test (TPAT) and the maximum hip rotation arc midpoint (Arc midpoint) and for external tibial torsion the transmalleolar axis (TMA). Results showed that all physical examination measurements statistically differed to the CT-scans (bias(standard deviation): -2(14) for TPAT, -10(12) for Arc midpoint and -16(9) for TMA). Bland and Altman plots showed that method disagreements increased with increasing bony torsions in all cases but notably for TPAT. Regression analysis showed that only TMA and CT-scan measurement of external tibial torsion demonstrated good (R(2)=57%) correlation. Correlations for both TPAT (R(2)=14%) and Arc midpoint (R(2)=39%) with CT-scan measurements of FNA were limited. We conclude that physical examination should be considered as screening techniques rather than definitive measurement methods for FNA and ETT. Further research is required to develop more accurate measurement methods to accompany instrumented gait analysis.

  8. Adrenal metastasis from differentiated thyroid carcinoma documented on post-therapy 131I scan: A case based discussion

    PubMed Central

    Ranade, Rohit; Thapa, Pradeep; Basu, Sandip

    2014-01-01

    Adrenal metastasis is an unusual site of disease involvement in the natural course of differentiated thyroid carcinoma (DTC). This paper discusses the clinical and imaging features of DTC with adrenal metastasis. An unusual case of unilateral solitary asymptomatic adrenal metastasis in the setting of DTC is described in this report with the imaging features including 131I scintigraphy and Fluorodeoxyglucose- Positron emission tomography/computed tomography. The adrenal metastasis was associated with other sites of metastatic disease involvement and was unidentified on initial pre-treatment evaluation studies. All such suspicious lesions should be further evaluated with clinicoradiological correlation by other imaging modalities. A post-radioiodine therapy scan revealed radioiodine uptake in the thyroid bed, sternum and a focus of intense radioiodine concentration in the left suprarenal region. Spot oblique images and single photon emission computed tomography of the upper abdomen was undertaken to ascertain the position and better characterization of the lesion. A subsequent whole body PET-CT (non-contrast) was done which revealed a well defined 6.5 cm × 5.0 cm left adrenal lesion with a SUVmax (standardized uptake value-maximum) of 9.5 in addition to a fluorodeoxyglucose avid osteolytic sternal lesion. The serum thyroglobulin level was significantly raised (more than 250 ng/mL) with thyroid stimulating hormone being 4.9 μΙU/mL (even following an adequate period of levothyroxine withdrawal), indicating the functioning nature of the metastases. In addition to demonstrating an atypical site of metastatic disease in DTC patients, this case emphasizes the importance of carefully interpreting and correlating a post radio-iodine therapy scan, particularly those with focal abdominal radio-iodine uptake which could aid in detecting metastatic lesions that are not characterized or identified on initial evaluation. The other important feature that can be deciphered from

  9. Evaluation of radiation dose of triple rule-out coronary angiography protocols with different scan length using 256-slice CT

    NASA Astrophysics Data System (ADS)

    Tsai, Chia-Jung; Lee, Jason J. S.; Chen, Liang-Kuang; Mok, Greta S. P.; Hsu, Shih-Ming; Wu, Tung-Hsin

    2011-10-01

    Triple rule-out coronary CT angiography (TRO-CTA) is a new approach for providing noninvasive visualization of coronary arteries with simultaneous evaluation of pulmonary arteries, thoracic aorta and other intrathoracic structures. The increasing use of TRO-CTA examination with longer scan length is associated with the concerns about radiation dose and their corresponding cancer risk. The purpose of this study is to evaluate organ dose and effective dose for the TRO-CTA examination with 2 scan lengths: TRO std and TRO ext, using 256-slice CT. TRO-CTA examinations were performed on a 256-slice CT scanner without ECG-based tube current modulation. Absorbed organ doses were measured using an anthropomorphic phantom and thermal-luminance dosimeters (TLDs). Effective dose was determined by taking a sum of the measured absorbed organ doses multiplied with the tissue weighting factor based on ICRP-103, and compared to that calculated using the dose-length product (DLP) method. We obtained high organ doses in the thyroid, esophagus, breast, heart and lung in both TRO-CTA protocols. Effective doses of the TRO std and TRO ext protocols with the phantom method were 26.37 and 42.49 mSv, while those with the DLP method were 19.68 and 38.96 mSv, respectively. Our quantitative dose information establishes a relationship between radiation dose and scanning length, and can provide a practical guidance to best clinical practice.

  10. CT Appearance of Hepatocellular Carcinoma after Locoregional Treatments: A Comprehensive Review

    PubMed Central

    Marin, Daniel; Cappabianca, Salvatore; Serra, Nicola; Sica, Assunta; D'Angelo, Roberto; La Porta, Michelearcangelo; Fiore, Francesco; Somma, Francesco

    2015-01-01

    Hepatocellular carcinoma (HCC) is a major health problem worldwide, affecting more than 600,000 new patients per year. Curative treatments are available in a small percentage of patients, while most of them present in stages requiring locoregional treatments such as thermoablation, transarterial chemoembolization, and/or radioembolization. These therapies result in specific imaging features that the general radiologist has to be aware of in order to assess the response to treatment and to correctly manage the follow-up of treated patients. Multiphasic helical computed tomography has become a popular imaging modality for detecting hypervascular tumors and characterizing liver lesions. On this basis, many staging and diagnostic systems have been proposed for evaluating response to all different existing strategies. Radiofrequencies and microwaves generate thermoablation of tumors, and transarterial chemoembolization exploits the double effect of the locoregional administration of drugs and embolizing particles. Eventually radioembolization uses a beta-emitting isotope to induce necrosis. Therefore, the aim of this comprehensive review is to analyze and compare CT imaging appearance of HCC after various locoregional treatments, with regard to specific indications for all possible procedures. PMID:26798332

  11. CT Appearance of Hepatocellular Carcinoma after Locoregional Treatments: A Comprehensive Review.

    PubMed

    Marin, Daniel; Cappabianca, Salvatore; Serra, Nicola; Sica, Assunta; Lassandro, Francesco; D'Angelo, Roberto; La Porta, Michelearcangelo; Fiore, Francesco; Somma, Francesco

    2015-01-01

    Hepatocellular carcinoma (HCC) is a major health problem worldwide, affecting more than 600,000 new patients per year. Curative treatments are available in a small percentage of patients, while most of them present in stages requiring locoregional treatments such as thermoablation, transarterial chemoembolization, and/or radioembolization. These therapies result in specific imaging features that the general radiologist has to be aware of in order to assess the response to treatment and to correctly manage the follow-up of treated patients. Multiphasic helical computed tomography has become a popular imaging modality for detecting hypervascular tumors and characterizing liver lesions. On this basis, many staging and diagnostic systems have been proposed for evaluating response to all different existing strategies. Radiofrequencies and microwaves generate thermoablation of tumors, and transarterial chemoembolization exploits the double effect of the locoregional administration of drugs and embolizing particles. Eventually radioembolization uses a beta-emitting isotope to induce necrosis. Therefore, the aim of this comprehensive review is to analyze and compare CT imaging appearance of HCC after various locoregional treatments, with regard to specific indications for all possible procedures. PMID:26798332

  12. A “loop” shape descriptor and its application to automated segmentation of airways from CT scans

    SciTech Connect

    Pu, Jiantao; Jin, Chenwang Yu, Nan; Qian, Yongqiang; Guo, Youmin; Wang, Xiaohua; Meng, Xin

    2015-06-15

    Purpose: A novel shape descriptor is presented to aid an automated identification of the airways depicted on computed tomography (CT) images. Methods: Instead of simplifying the tubular characteristic of the airways as an ideal mathematical cylindrical or circular shape, the proposed “loop” shape descriptor exploits the fact that the cross sections of any tubular structure (regardless of its regularity) always appear as a loop. In implementation, the authors first reconstruct the anatomical structures in volumetric CT as a three-dimensional surface model using the classical marching cubes algorithm. Then, the loop descriptor is applied to locate the airways with a concave loop cross section. To deal with the variation of the airway walls in density as depicted on CT images, a multiple threshold strategy is proposed. A publicly available chest CT database consisting of 20 CT scans, which was designed specifically for evaluating an airway segmentation algorithm, was used for quantitative performance assessment. Measures, including length, branch count, and generations, were computed under the aid of a skeletonization operation. Results: For the test dataset, the airway length ranged from 64.6 to 429.8 cm, the generation ranged from 7 to 11, and the branch number ranged from 48 to 312. These results were comparable to the performance of the state-of-the-art algorithms validated on the same dataset. Conclusions: The authors’ quantitative experiment demonstrated the feasibility and reliability of the developed shape descriptor in identifying lung airways.

  13. Interfractional Prostate Shifts: Review of 1870 Computed Tomography (CT) Scans Obtained During Image-Guided Radiotherapy Using CT-on-Rails for the Treatment of Prostate Cancer

    SciTech Connect

    Wong, James R. Gao Zhanrong; Uematsu, Minoru; Merrick, Scott; Machernis, Nolan P.; Chen, Timothy; Cheng, C.W.

    2008-12-01

    Purpose: To review 1870 CT scans of interfractional prostate shift obtained during image-guided radiotherapy. Methods and Materials: A total of 1870 pretreatment CT scans were acquired with CT-on-rails, and the corresponding shift data for 329 patients with prostate cancer were analyzed. Results: Of the 1870 scans reviewed, 44% required no setup adjustments in the anterior-posterior (AP) direction, 14% had shifts of 3-5 mm, 29% had shifts of 6-10 mm, and 13% had shifts of >10 mm. In the superior-inferior direction, 81% had no adjustments, 2% had shifts of 3-5 mm, 15% had shifts of 6-10 mm, and 2% had shifts of >10 mm. In the left-right direction, 65% had no adjustment, 13% had shifts of 3-5 mm, 17% had shifts of 6-10 mm, and 5% had shifts of >10 mm. Further analysis of the first 66 consecutive patients divided into three groups according to body mass index indicates that the shift in the AP direction for the overweight subgroup was statistically larger than those for the control and obese subgroups (p < 0.05). The interfractional shift in the lateral direction for the obese group (1 SD, 5.5 mm) was significantly larger than those for the overweight and control groups (4.1 and 2.9 mm, respectively) (p < 0.001). Conclusions: These data demonstrate that there is a significantly greater shift in the AP direction than in the lateral and superior-inferior directions for the entire patient group. Overweight and obese patient groups show a significant difference from the control group in terms of prostate shift.

  14. Role of CT Perfusion in Monitoring and Prediction of Response to Therapy of Head and Neck Squamous Cell Carcinoma

    PubMed Central

    Preda, Lorenzo; Moscatelli, Marco Elvio Manlio; Cossu Rocca, Maria

    2014-01-01

    This review aims to summarize the technique and clinical applications of CT perfusion (CTp) of head and neck cancer. The most common pathologic type (90%) of head and neck cancer is squamous cell carcinoma (HNSCC): its diagnostic workup relies on CT and MRI, as they provide an accurate staging for the disease by determining tumour volume, assessing its extension, and detecting of lymph node metastases. Compared with conventional CT and MRI, CTp allows for obtaining measures of tumour vascular physiology and functional behaviour, and it has been demonstrated to be a feasible and useful tool in predicting local outcomes in patients undergoing radiation therapy and chemotherapy and may help monitor both treatments. PMID:25140324

  15. SCAN+

    SciTech Connect

    Kenneth Krebs, John Svoboda

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.

  16. Automatic segmentation of phase-correlated CT scans through nonrigid image registration using geometrically regularized free-form deformation

    SciTech Connect

    Shekhar, Raj; Lei, Peng; Castro-Pareja, Carlos R.; Plishker, William L.; D'Souza, Warren D.

    2007-07-15

    Conventional radiotherapy is planned using free-breathing computed tomography (CT), ignoring the motion and deformation of the anatomy from respiration. New breath-hold-synchronized, gated, and four-dimensional (4D) CT acquisition strategies are enabling radiotherapy planning utilizing a set of CT scans belonging to different phases of the breathing cycle. Such 4D treatment planning relies on the availability of tumor and organ contours in all phases. The current practice of manual segmentation is impractical for 4D CT, because it is time consuming and tedious. A viable solution is registration-based segmentation, through which contours provided by an expert for a particular phase are propagated to all other phases while accounting for phase-to-phase motion and anatomical deformation. Deformable image registration is central to this task, and a free-form deformation-based nonrigid image registration algorithm will be presented. Compared with the original algorithm, this version uses novel, computationally simpler geometric constraints to preserve the topology of the dense control-point grid used to represent free-form deformation and prevent tissue fold-over. Using mean squared difference as an image similarity criterion, the inhale phase is registered to the exhale phase of lung CT scans of five patients and of characteristically low-contrast abdominal CT scans of four patients. In addition, using expert contours for the inhale phase, the corresponding contours were automatically generated for the exhale phase. The accuracy of the segmentation (and hence deformable image registration) was judged by comparing automatically segmented contours with expert contours traced directly in the exhale phase scan using three metrics: volume overlap index, root mean square distance, and Hausdorff distance. The accuracy of the segmentation (in terms of radial distance mismatch) was approximately 2 mm in the thorax and 3 mm in the abdomen, which compares favorably to the

  17. Lung texture in serial thoracic CT scans: correlation with radiologist-defined severity of acute changes following radiation therapy

    NASA Astrophysics Data System (ADS)

    Cunliffe, Alexandra R.; Armato, Samuel G., III; Straus, Christopher; Malik, Renuka; Al-Hallaq, Hania A.

    2014-09-01

    This study examines the correlation between the radiologist-defined severity of normal tissue damage following radiation therapy (RT) for lung cancer treatment and a set of mathematical descriptors of computed tomography (CT) scan texture (‘texture features’). A pre-therapy CT scan and a post-therapy CT scan were retrospectively collected under IRB approval for each of the 25 patients who underwent definitive RT (median dose: 66 Gy). Sixty regions of interest (ROIs) were automatically identified in the non-cancerous lung tissue of each post-therapy scan. A radiologist compared post-therapy scan ROIs with pre-therapy scans and categorized each as containing no abnormality, mild abnormality, moderate abnormality, or severe abnormality. Twenty texture features that characterize gray-level intensity, region morphology, and gray-level distribution were calculated in post-therapy scan ROIs and compared with anatomically matched ROIs in the pre-therapy scan. Linear regression and receiver operating characteristic (ROC) analysis were used to compare the percent feature value change (ΔFV) between ROIs at each category of visible radiation damage. Most ROIs contained no (65%) or mild abnormality (30%). ROIs with moderate (3%) or severe (2%) abnormalities were observed in 9 patients. For 19 of 20 features, ΔFV was significantly different among severity levels. For 12 features, significant differences were observed at every level. Compared with regions with no abnormalities, ΔFV for these 12 features increased, on average, by 1.5%, 12%, and 30%, respectively, for mild, moderate, and severe abnormalitites. Area under the ROC curve was largest when comparing ΔFV in the highest severity level with the remaining three categories (mean AUC across features: 0.84). In conclusion, 19 features that characterized the severity of radiologic changes from pre-therapy scans were identified. These features may be used in future studies to quantify acute normal lung tissue damage

  18. Estimation of radiation dose to patients from 18FDG whole body PET/CT investigations using dynamic PET scan protocol

    PubMed Central

    Kaushik, Aruna; Jaimini, Abhinav; Tripathi, Madhavi; D’Souza, Maria; Sharma, Rajnish; Mondal, Anupam; Mishra, Anil K.; Dwarakanath, Bilikere S.

    2015-01-01

    Background & objectives: There is a growing concern over the radiation exposure of patients from undergoing 18FDG PET/CT (18F-fluorodeoxyglucose positron emission tomography/computed tomography) whole body investigations. The aim of the present study was to study the kinetics of 18FDG distributions and estimate the radiation dose received by patients undergoing 18FDG whole body PET/CT investigations. Methods: Dynamic PET scans in different regions of the body were performed in 49 patients so as to measure percentage uptake of 18FDG in brain, liver, spleen, adrenals, kidneys and stomach. The residence time in these organs was calculated and radiation dose was estimated using OLINDA software. The radiation dose from the CT component was computed using the software CT-Expo and measured using computed tomography dose index (CTDI) phantom and ionization chamber. As per the clinical protocol, the patients were refrained from eating and drinking for a minimum period of 4 h prior to the study. Results: The estimated residence time in males was 0.196 h (brain), 0.09 h (liver), 0.007 h (spleen), 0.0006 h (adrenals), 0.013 h (kidneys) and 0.005 h (stomach) whereas it was 0.189 h (brain), 0.11 h (liver), 0.01 h (spleen), 0.0007 h (adrenals), 0.02 h (kidneys) and 0.004 h (stomach) in females. The effective dose was found to be 0.020 mSv/MBq in males and 0.025 mSv/MBq in females from internally administered 18FDG and 6.8 mSv in males and 7.9 mSv in females from the CT component. For an administered activity of 370 MBq of 18FDG, the effective dose from PET/CT investigations was estimated to be 14.2 mSv in males and 17.2 mSv in females. Interpretation & conclusions: The present results did not demonstrate significant difference in the kinetics of 18FDG distribution in male and female patients. The estimated PET/CT doses were found to be higher than many other conventional diagnostic radiology examinations suggesting that all efforts should be made to clinically justify and

  19. Combined Use of Automatic Tube Voltage Selection and Current Modulation with Iterative Reconstruction for CT Evaluation of Small Hypervascular Hepatocellular Carcinomas: Effect on Lesion Conspicuity and Image Quality

    PubMed Central

    Lv, Peijie; Liu, Jie; Zhang, Rui; Jia, Yan

    2015-01-01

    Objective To assess the lesion conspicuity and image quality in CT evaluation of small (≤ 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction. Materials and Methods One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups. Results Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022). Conclusion CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction. PMID:25995682

  20. Semiautomated three-dimensional segmentation software to quantify carpal bone volume changes on wrist CT scans for arthritis assessment.

    PubMed

    Duryea, J; Magalnick, M; Alli, S; Yao, L; Wilson, M; Goldbach-Mansky, R

    2008-06-01

    Rapid progression of joint destruction is an indication of poor prognosis in patients with rheumatoid arthritis. Computed tomography (CT) has the potential to serve as a gold standard for joint imaging since it provides high resolution three-dimensional (3D) images of bone structure. The authors have developed a method to quantify erosion volume changes on wrist CT scans. In this article they present a description and validation of the methodology using multiple scans of a hand phantom and five human subjects. An anthropomorphic hand phantom was imaged with a clinical CT scanner at three different orientations separated by a 30-deg angle. A reader used the semiautomated software tool to segment the individual carpal bones of each CT scan. Reproducibility was measured as the root-mean-square standard deviation (RMMSD) and coefficient of variation (CoV) between multiple measurements of the carpal volumes. Longitudinal erosion progression was studied by inserting simulated erosions in a paired second scan. The change in simulated erosion size was calculated by performing 3D image registration and measuring the volume difference between scans in a region adjacent to the simulated erosion. The RMSSD for the total carpal volumes was 21.0 mm3 (CoV = 1.3%) for the phantom, and 44.1 mm3 (CoV = 3.0%) for the in vivo subjects. Using 3D registration and local volume difference calculations, the RMMSD was 1.0-3.0 mm3 The reader time was approximately 5 min per carpal bone. There was excellent agreement between the measured and simulated erosion volumes. The effect of a poorly measured volume for a single erosion is mitigated by the large number of subjects that would comprise a clinical study and that there will be many erosions measured per patient. CT promises to be a quantifiable tool to measure erosion volumes and may serve as a gold standard that can be used in the validation of other modalities such as magnetic resonance imaging.

  1. Fludeoxyglucose F 18 PET Scan, CT Scan, and Ferumoxtran-10 MRI Scan Before Chemotherapy and Radiation Therapy in Finding Lymph Node Metastasis in Patients With Locally Advanced Cervical Cancer or High-Risk Endometrial Cancer

    ClinicalTrials.gov

    2016-09-19

    Cervical Adenocarcinoma; Cervical Adenosquamous Cell Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Endometrial Clear Cell Carcinoma; Endometrial Papillary Serous Carcinoma; Stage I Endometrial Carcinoma; Stage IB Cervical Cancer; Stage II Endometrial Carcinoma; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage III Endometrial Carcinoma; Stage IVA Cervical Cancer

  2. SU-E-CAMPUS-J-06: The Impact of CT-Scan Energy On Range Uncertainty in Proton Therapy Planning

    SciTech Connect

    Grantham, K; Li, H; Zhao, T; Klein, E

    2014-06-15

    Purpose: To investigate the impact of tube potential (kVp) on the CTnumber (HU) to proton stopping power ratio (PSPR) conversion table; the range uncertainty and the dosimetric change introduced by a mismatch in kVp between the CT and the HU to PSPR table used to calculate dose are analyzed. Methods: A CIRS CT-ED phantom was scanned with a Philips Brilliance 64-slice scanner under 90kVp and 120kVp tube potentials. Two HU to PSPR curves were then created. Using Eclipse (Varian) a treatment plan was created for a single beam in a water phantom (HU=0) passing through a wedge-shaped heterogeneity (HU=1488). The dose was recalculated by changing only the HU to PSPR table used in the dose calculation. The change in range (the distal 90% isodose line) relative to a distal structure was recorded as a function of heterogeneity thickness in the beam. To show the dosimetric impact of a mismatch in kVp between the CT and the HU to PSPR table, we repeated this procedure using a clinical plan comparing DVH data. Results: The HU to PSPR tables diverge for low-density bone and higher density structures. In the phantom plan, the divergence of the tables results in a change in range of ~1mm per cm of bone in the beam path for the HU used. For the clinical plan, a mismatch in kVp showed a 28% increase in mean dose to the brainstem along with a 10% increase in maximum dose to the brainstem center. Conclusion: A mismatch in kVp between the CT and the HU to PSPR table can introduce significant uncertainty in the proton beam range. For dense bone, the measured range uncertainty is about 1mm per cm of bone in the beam. CT-scan energy verification should be employed, particularly when high-density media is in the proton beam path.

  3. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    PubMed Central

    2011-01-01

    Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast) and preoperative (radiographic template) models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology. PMID:21338504

  4. Experimental Investigation into Hydraulic Fracture Network Propagation in Gas Shales Using CT Scanning Technology

    NASA Astrophysics Data System (ADS)

    Yushi, Zou; Shicheng, Zhang; Tong, Zhou; Xiang, Zhou; Tiankui, Guo

    2016-01-01

    Multistage fracturing of the horizontal well is recognized as the main stimulation technology for shale gas development. The hydraulic fracture geometry and stimulated reservoir volume (SRV) is interpreted by using the microseismic mapping technology. In this paper, we used a computerized tomography (CT) scanning technique to reveal the fracture geometry created in natural bedding-developed shale (cubic block of 30 cm × 30 cm × 30 cm) by laboratory fracturing. Experimental results show that partially opened bedding planes are helpful in increasing fracture complexity in shale. However, they tend to dominate fracture patterns for vertical stress difference Δ σ v ≤ 6 MPa, which decreases the vertical fracture number, resulting in the minimum SRV. A uniformly distributed complex fracture network requires the induced hydraulic fractures that can connect the pre-existing fractures as well as pulverize the continuum rock mass. In typical shale with a narrow (<0.05 mm) and closed natural fracture system, it is likely to create complex fracture for horizontal stress difference Δ σ h ≤ 6 MPa and simple transverse fracture for Δ σ h ≥ 9 MPa. However, high naturally fractured shale with a wide open natural fracture system (>0.1 mm) does not agree with the rule that low Δ σ h is favorable for uniformly creating a complex fracture network in zone. In such case, a moderate Δ σ h from 3 to 6 MPa is favorable for both the growth of new hydraulic fractures and the activation of a natural fracture system. Shale bedding, natural fracture, and geostress are objective formation conditions that we cannot change; we can only maximize the fracture complexity by controlling the engineering design for fluid viscosity, flow rate, and well completion type. Variable flow rate fracturing with low-viscosity slickwater fluid of 2.5 mPa s was proved to be an effective treatment to improve the connectivity of induced hydraulic fracture with pre-existing fractures. Moreover, the

  5. CT head-scan dosimetry in an anthropomorphic phantom and associated measurement of ACR accreditation-phantom imaging metrics under clinically representative scan conditions

    SciTech Connect

    Brunner, Claudia C.; Stern, Stanley H.; Chakrabarti, Kish; Minniti, Ronaldo; Parry, Marie I.; Skopec, Marlene

    2013-08-15

    Purpose: To measure radiation absorbed dose and its distribution in an anthropomorphic head phantom under clinically representative scan conditions in three widely used computed tomography (CT) scanners, and to relate those dose values to metrics such as high-contrast resolution, noise, and contrast-to-noise ratio (CNR) in the American College of Radiology CT accreditation phantom.Methods: By inserting optically stimulated luminescence dosimeters (OSLDs) in the head of an anthropomorphic phantom specially developed for CT dosimetry (University of Florida, Gainesville), we measured dose with three commonly used scanners (GE Discovery CT750 HD, Siemens Definition, Philips Brilliance 64) at two different clinical sites (Walter Reed National Military Medical Center, National Institutes of Health). The scanners were set to operate with the same data-acquisition and image-reconstruction protocols as used clinically for typical head scans, respective of the practices of each facility for each scanner. We also analyzed images of the ACR CT accreditation phantom with the corresponding protocols. While the Siemens Definition and the Philips Brilliance protocols utilized only conventional, filtered back-projection (FBP) image-reconstruction methods, the GE Discovery also employed its particular version of an adaptive statistical iterative reconstruction (ASIR) algorithm that can be blended in desired proportions with the FBP algorithm. We did an objective image-metrics analysis evaluating the modulation transfer function (MTF), noise power spectrum (NPS), and CNR for images reconstructed with FBP. For images reconstructed with ASIR, we only analyzed the CNR, since MTF and NPS results are expected to depend on the object for iterative reconstruction algorithms.Results: The OSLD measurements showed that the Siemens Definition and the Philips Brilliance scanners (located at two different clinical facilities) yield average absorbed doses in tissue of 42.6 and 43.1 m

  6. Multi-modal CT scanning in the evaluation of cerebrovascular disease patients

    PubMed Central

    Anzidei, Michele; Piga, Mario; Ciolina, Federica; Mannelli, Lorenzo; Catalano, Carlo; Suri, Jasjit S.; Raz, Eytan

    2014-01-01

    Ischemic stroke currently represents one of the leading causes of severe disability and mortality in the Western World. Until now, angiography was the most used imaging technique for the detection of the extra-cranial and intracranial vessel pathology. Currently, however, non-invasive imaging tool like ultrasound (US), magnetic resonance (MR) and computed tomography (CT) have proven capable of offering a detailed analysis of the vascular system. CT in particular represents an advanced system to explore the pathology of carotid arteries and intracranial vessels and also offers tools like CT perfusion (CTP) that provides valuable information of the brain’s vascular physiology by increasing the stroke diagnostic. In this review, our purpose is to discuss stroke risk prediction and detection using CT. PMID:25009794

  7. Optical CT scanning of PRESAGETM polyurethane samples with a CCD-based readout system

    NASA Astrophysics Data System (ADS)

    Doran, S. J.; Krstajic, N.; Adamovics, J.; Jenneson, P. M.

    2004-01-01

    This article demonstrates the resolution capabilities of the CCD scanner under ideal circumstances and describes the first CCD-based optical CT experiments on a new class of dosimeter, known as PRESAGETM (Heuris Pharma, Skillman, NJ).

  8. SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

    SciTech Connect

    Ranallo, F; Szczykutowicz, T

    2014-06-01

    Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare.

  9. A computerized scheme for localization of vertebral bodies on body CT scans

    NASA Astrophysics Data System (ADS)

    Hayashi, Tatsuro; Chen, Huayue; Miyamoto, Kei; Zhou, Xiangrong; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2011-03-01

    The multidetector row computed tomography (MDCT) method has the potential to be used for quantitative analysis of osteoporosis with higher accuracy and precision than that provided by conventional two-dimensional methods. It is desirable to develop a computer-assisted scheme for analyzing vertebral geometry using body CT images. The aim of this study was to design a computerized scheme for the localization of vertebral bodies on body CT images. Our new scheme involves the following steps: (i) Re-formation of CT images on the basis of the center line of the spinal canal to visually remove the spinal curvature, (ii) use of information on the position of the ribs relative to the vertebral bodies, (iii) the construction of a simple model on the basis of the contour of the vertebral bodies on CT sections, and (iv) the localization of individual vertebral bodies by using a template matching technique. The proposed scheme was applied to 104 CT cases, and its performance was assessed using the Hausdorff distance. The average Hausdorff distance of T2-L5 was 4.3 mm when learning models with 100 samples were used. On the other hand, the average Hausdorff distance with 10 samples was 5.1 mm. The results of our assessments confirmed that the proposed scheme could provide the location of individual vertebral bodies. Therefore, the proposed scheme may be useful in designing a computer-based application that analyzes vertebral geometry on body CT images.

  10. Variation of patient imaging doses with scanning parameters for linac-integrated kilovoltage cone beam CT.

    PubMed

    Liao, Xiongfei; Wang, Yunlai; Lang, Jinyi; Wang, Pei; Li, Jie; Ge, Ruigang; Yang, Jack

    2015-01-01

    To evaluate the Elekta kilovoltage CBCT doses and the associated technical protocols with patient dosimetry estimation. Image guidance technique with cone-beam CT (CBCT) in radiation oncology on a daily basis can deliver a significant dose to the patient. To evaluate the patient dose from LINAC-integrated kV cone beam CT imaging in image-guided radiotherapy. CT dose index (CTDI) were measured with PTW TM30009 CT ion chamber in air, in head phantom and body phantom, respectively; with different combinations of tube voltage, current, exposure time per frame, collimator and gantry rotation range. Dose length products (DLP) were subsequently calculated to account for volume integration effects. The CTDI and DLP were also compared to AcQSim™ simulator CT for routine clinical protocols. Both CTDIair and CTDIw depended quadratically on the voltage, while linearly on milliampere x seconds (mAs) settings. It was shown that CTDIw and DLP had very close relationship with the collimator settings and the gantry rotation ranges. Normalized CTDIw for Elekta XVI™ CBCT was lower than that of ACQSim simulator CT owing to its pulsed radiation output characteristics. CTDIw can be used to assess the patient dose in CBCT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA & QC program. Optimal image parameters should be chosen to reduce patient dose during CBCT. PMID:26405932

  11. Computer tomographic imaging and anatomic correlation of the human brain: A comparative atlas of thin CT-scan sections and correlated neuro-anatomic preparations

    SciTech Connect

    Plets, C.; Baert, A.L.; Nijs, G.L.; Wilms, G.

    1986-01-01

    It is of the greatest importance to the radiologist, the neurologist and the neurosurgeon to be able to localize topographically a pathological brain process on the CT scan as precisely as possible. For that purpose, the identification of as many anatomical structures as possible on the CT scan image are necessary and indispensable. In this atlas a great number of detailed anatomical data on frontal horizontal CT scan sections, each being only 2 mm thick, are indicated, e.g. the cortical gyri, the basal ganglia, details of the white matter, extracranial muscles and blood vessels, parts of the base and the vault of the skull, etc. The very precise topographical description of the numerous CT scan images was realized by the author by confrontation of these images with the corresponding anatomical sections of the same brain specimen, performed by an original technique.

  12. SCAN+

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determinemore » the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.« less

  13. Prediction of Pathologic Grade and Prognosis in Mucoepidermoid Carcinoma of the Lung Using 18F-FDG PET/CT

    PubMed Central

    Park, Byungjoon; Kim, Hong Kwan; Choi, Yong Soo; Kim, Jhingook; Zo, Jae Il; Choi, Joon Young

    2015-01-01

    Objective The maximum standardized uptake value (SUVmax) of pulmonary mucoepidermoid carcinoma (PMEC) in fluorine-18fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) was evaluated as a preoperative predictor of pathologic grade and survival rate. Materials and Methods Twenty-three patients who underwent preoperative PET/CT and complete resection for PMEC were enrolled. The optimal cut-off SUVmax for tumor grade was calculated as 6.5 by receiver operating characteristic curve. The patients were divided into a high SUV group (n = 7) and a low SUV group (n = 16). Clinicopathologic features were compared between the groups by χ2 test and overall survival was determined by Kaplan-Meier analysis. Results The mean SUVmax was 15.4 ± 11.5 in the high SUV group and 3.9 ± 1.3 in the low SUV group. All patients except one from the low SUV group had low grade tumors and all had no nodal metastasis. The sensitivity and specificity of SUVmax from PET/CT for predicting tumor grade was 85.7% and 93.8%, respectively. During the follow-up period (mean, 48.6 ± 38.7 months), four patients from the high SUV group experienced cancer recurrence, and one died of cancer. In contrast, none of the low SUV group had recurrence or mortality. Five-year overall survival rate was significantly higher in the low SUV group (100% vs. 71.4%, p = 0.031). Conclusion Pulmonary mucoepidermoid carcinoma patients with high SUVmax in PET/CT had higher tumor grade, more frequent lymph node metastasis and worse long-term outcome. Therefore, PMEC patients with high uptake on PET/CT imaging might require aggressive mediastinal lymph node dissection and adjuvant therapies. PMID:26175595

  14. Contrast Enhancement of MicroCT Scans to Aid 3D Modelling of Carbon Fibre Fabric Composites

    NASA Astrophysics Data System (ADS)

    Djukic, Luke P.; Pearce, Garth M.; Herszberg, Israel; Bannister, Michael K.; Mollenhauer, David H.

    2013-12-01

    This paper presents a methodology for volume capture and rendering of plain weave and multi-layer fabric meso-architectures within a consolidated, cured laminate. Micro X-ray Computed Tomography (MicroCT) is an excellent tool for the non-destructive visualisation of material microstructures however the contrast between tows and resin is poor for carbon fibre composites. Firstly, this paper demonstrates techniques to improve the contrast of the microCT images by introducing higher density materials such as gold, iodine and glass into the fabric. Two approaches were demonstrated to be effective for enhancing the differentiation between the tows in the reconstructed microCT visualisations. Secondly, a method of generating three-dimensional volume models of woven composites using microCT scan data is discussed. The process of generating a model is explained from initial manufacture with the aid of an example plain weave fabric. These methods are to be used in the finite element modelling of three-dimensional fabric preforms in future work.

  15. Do 18F-FDG PET/CT parameters in oropharyngeal and oral cavity squamous cell carcinomas indicate HPV status?

    PubMed Central

    Kendi, AT; Magliocca, K; Corey, A; Nickleach, DC; Galt, J; Higgins, K; Beitler, JJ; El-Deiry, MW; Wadsworth, JT; Hudgins, PA; Saba, NF; Schuster, DM

    2014-01-01

    Objective To explore the relationship of PET/CT parameters with HPV status of oropharyngeal (OP) and oral cavity (OC) squamous cell carcinomas (SCC). Material and Methods We retrospectively reviewed 39 patients with OC and OP SCC who underwent staging 18F-FDG PET/CT. PET/CT parameters were measured for the primary tumor and the hottest involved node, including maximum, mean, peak standardized uptake values (SUV max, SUV mean, SUV peak), metabolic tumor volume (MTV), total lesion glycolysis (TLG), standardized added metabolic activity (SAM), normalized standardized added metabolic activity (N SAM). Patient characteristics compared between HPV positive (HPV+) and negative (HPV−) groups. ROC analysis was used to dichotomize PET/CT parameters into high and low. Logistic regression models predicting HPV status were fit for each PET/CT parameter. Results The HPV+ group was comprised of 18 patients all with OP SCC; the HPV− group consisted of 21 patients, 4 OP cancer patients and 17 OC cancer patients. The HPV+ group had a higher proportion of N2 stage (94% vs 43%; p<0.001). Nodal PET/CT parameters were higher in the HPV+ group (p<0.01), this difference was not present for the primary lesion. After adjusting for sex and age, the association of higher nodal SUV max (OR 9.67), SUV mean (OR 10.48), SUV peak (OR 9.67), MTV (OR 14.52), TLG (OR 11.84) and SAM, N SAM (OR 16.21) with HPV+ status remained statistically significant (p<0.05). Conclusion Nodal PET/CT parameters predict HPV status. High nodal FDG uptake should raise suspicion for positive HPV status in the evaluation of the primary lesion. PMID:25608156

  16. Application of the Semi-Empirical Force-Limiting Approach for the CoNNeCT SCAN Testbed

    NASA Technical Reports Server (NTRS)

    Staab, Lucas D.; McNelis, Mark E.; Akers, James C.; Suarez, Vicente J.; Jones, Trevor M.

    2012-01-01

    The semi-empirical force-limiting vibration method was developed and implemented for payload testing to limit the structural impedance mismatch (high force) that occurs during shaker vibration testing. The method has since been extended for use in analytical models. The Space Communications and Navigation Testbed (SCAN Testbed), known at NASA as, the Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT), project utilized force-limiting testing and analysis following the semi-empirical approach. This paper presents the steps in performing a force-limiting analysis and then compares the results to test data recovered during the CoNNeCT force-limiting random vibration qualification test that took place at NASA Glenn Research Center (GRC) in the Structural Dynamics Laboratory (SDL) December 19, 2010 to January 7, 2011. A compilation of lessons learned and considerations for future force-limiting tests is also included.

  17. Fuzzy Clustering Applied to ROI Detection in Helical Thoracic CT Scans with a New Proposal and Variants.

    PubMed

    Castro, Alfonso; Rey, Alberto; Boveda, Carmen; Arcay, Bernardino; Sanjurjo, Pedro

    2016-01-01

    The detection of pulmonary nodules is one of the most studied problems in the field of medical image analysis due to the great difficulty in the early detection of such nodules and their social impact. The traditional approach involves the development of a multistage CAD system capable of informing the radiologist of the presence or absence of nodules. One stage in such systems is the detection of ROI (regions of interest) that may be nodules in order to reduce the space of the problem. This paper evaluates fuzzy clustering algorithms that employ different classification strategies to achieve this goal. After characterising these algorithms, the authors propose a new algorithm and different variations to improve the results obtained initially. Finally it is shown as the most recent developments in fuzzy clustering are able to detect regions that may be nodules in CT studies. The algorithms were evaluated using helical thoracic CT scans obtained from the database of the LIDC (Lung Image Database Consortium).

  18. Application of the Semi-Empirical Force-Limiting Approach for the CoNNeCT SCAN Testbed

    NASA Technical Reports Server (NTRS)

    Staab, Lucas; McNelis, Mark; Jones, Trevor; Suarez, Vicente; Akers, James

    2011-01-01

    The semi-empirical force-limited vibration method was developed and implemented for payload testing to limit the structural impedance mismatch (high force) that occurs during shaker vibration testing. The method has since been extended for use in analytical models. The Space Communications and Navigation Testbed (SCAN Testbed), known at NASA Glenn Research Center (GRC) as, the Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT) project utilized force-limited testing and analysis following the semi-empirical approach. This presentation presents the steps in performing a force-limited analysis and then compares the results to test data recovered during the CoNNeCT force-limited random vibration qualification test that took place at NASA Glenn Research Center (GRC) in the Structural Dynamics Laboratory (SDL) December 19, 2010 - January 7, 2011. A compilation of lessons learned and considerations for future force-limited tests is also included.

  19. A new role of PET/CT for target delineation for radiotherapy treatment planning for head and neck carcinomas.

    PubMed

    Zygogianni, Anna; Kyrgias, George; Kouvaris, John; Pistevou-Gompaki, Kyriaki; Kouloulias, Vassilis

    2012-01-01

    Fluorine-18-fluorodeoxyglucose- positron emission tomography ((18)F-FDG PET) in head and neck cancer patients is useful for staging, identification of macroscopic disease, detection of invaded lymph nodes and distant metastases, delineation of radiotherapy target volume and assessment of treatment response. This brief review addresses the potential role of PET in radiotherapy planning as compared to MRI and CT scan. Positron emission tomography is considered by radiation oncologists a useful test for the identification of the specific target volume for treatment. In addition, a number of hypoxia-related PET radiopharmaceuticals such as the fluorine-18-fluoromisonidazole ((18)F-FMISO) and the fluorine-18-fluoroazomycin arabinoside ((18)F-FAZA) are now available in order to identify hypoxic tumor subvolumes helping to implement new radiotherapy techniques. Magnetic resonance imaging (MRI) has the advantage to discriminate the soft tissue contrast from the tumor, against computerized tomography (CT), but PET/CT scans have the additional advantage to incorporate the metabolic imaging for improving the delineation of variable and hypoxic tumor tissue in the head and neck region. Regardless of the method used for determining the gross tumor volume, clinical examination remains irreplaceable. In conclusion, PET/CT offers complementary information for the delineation of the primary tumor and the corresponding lymph nodes compared to the use of MRI and CT and can support the use of modern radiotherapy techniques, having fewer toxicities.

  20. Construction of Abdominal Probabilistic Atlases and Their Value in Segmentation of Normal Organs in Abdominal CT Scans

    NASA Astrophysics Data System (ADS)

    Park, Hyunjin; Hero, Alfred; Bland, Peyton; Kessler, Marc; Seo, Jongbum; Meyer, Charles

    A good abdominal probabilistic atlas can provide important information to guide segmentation and registration applications in the abdomen. Here we build and test probabilistic atlases using 24 abdominal CT scans with available expert manual segmentations. Atlases are built by picking a target and mapping other training scans onto that target and then summing the results into one probabilistic atlas. We improve our previous abdominal atlas by 1) choosing a least biased target as determined by a statistical tool, i.e. multidimensional scaling operating on bending energy, 2) using a better set of control points to model the deformation, and 3) using higher information content CT scans with visible internal liver structures. One atlas is built in the least biased target space and two atlases are built in other target spaces for performance comparisons. The value of an atlas is assessed based on the resulting segmentations; whichever atlas yields the best segmentation performance is considered the better atlas. We consider two segmentation methods of abdominal volumes after registration with the probabilistic atlas: 1) simple segmentation by atlas thresholding and 2) application of a Bayesian maximum a posteriori method. Using jackknifing we measure the atlas-augmented segmentation performance with respect to manual expert segmentation and show that the atlas built in the least biased target space yields better segmentation performance than atlases built in other target spaces.

  1. Evaluation of exposure dose reduction in multislice CT coronary angiography (MS-CTA) with prospective ECG-gated helical scan

    NASA Astrophysics Data System (ADS)

    Ota, Takamasa; Tsuyuki, Masaharu; Okumura, Miwa; Sano, Tomonari; Kondo, Takeshi; Takase, Shinichi

    2008-03-01

    A novel low-dose ECG-gated helical scan method to investigate coronary artery diseases was developed. This method uses a high pitch for scanning (based on the patient's heart rate) and X-rays are generated only during the optimal cardiac phases. The dose reduction was obtained using a two-level approach: 1) To use a 64-slice CT scanner (Aquilion, Toshiba, Otawara, Tochigi, Japan) with a scan speed of 0.35 s/rot. to helically scan the heart at a high pitch based on the patient's heart rate. By changing the pitch from the conventional 0.175 to 0.271 for a heart rate of 60 bpm, the exposure dose was reduced to 65%. 2) To employ tube current gating that predicts the timing of optimal cardiac phases from the previous cardiac cycle and generates X-rays only during the required cardiac phases. The combination of high speed scanning with a high pitch and appropriate X-ray generation only in the cardiac phases from 60% to 90% allows the exposure dose to be reduced to 5.6 mSv for patients with a heart rate lower than 65 bpm. This is a dose reduction of approximately 70% compared to the conventional scanning method recommended by the manufacturer when segmental reconstruction is considered. This low-dose protocol seamlessly allows for wide scan ranges (e.g., aortic dissection) with the benefits of ECG-gated helical scanning: smooth continuity for longitudinal direction and utilization of data from all cardiac cycles.

  2. Intracranial lesions shown by CT scans in 259 cases of first alcohol-related seizures.

    PubMed

    Earnest, M P; Feldman, H; Marx, J A; Harris, J A; Biletch, M; Sullivan, L P

    1988-10-01

    We obtained CTs in 259 patients with a first alcohol-related convulsion. Each subject had generalized convulsions, recent abstinence from alcohol abuse, and no obvious etiology for seizures other than alcohol withdrawal. Patients with only focal seizures, major head injury, coma, or a severe toxic-metabolic disorder were excluded. We recorded history and signs of minor head injury, presence of headache, level of consciousness, neurologic signs, routine medical examination findings, and subsequent clinical course. Sixteen patients (6.2%) had intracranial lesions on CT. Eight had subdural hematomas or hygromas, two had vascular malformations, two had neurocysticercosis, and one each showed a Berry aneurysm, possible tumor, skull fracture with subarachnoid hemorrhage, and probable cerebral infarction. In ten cases (3.9%), clinical management was altered because of the CT result. History or signs of minor head trauma, headache, level of consciousness, or focal neurologic signs did not significantly correlate with CT abnormality.

  3. Unraveling the hydrodynamics of split root water uptake experiments using CT scanned root architectures and three dimensional flow simulations

    PubMed Central

    Koebernick, Nicolai; Huber, Katrin; Kerkhofs, Elien; Vanderborght, Jan; Javaux, Mathieu; Vereecken, Harry; Vetterlein, Doris

    2015-01-01

    Split root experiments have the potential to disentangle water transport in roots and soil, enabling the investigation of the water uptake pattern of a root system. Interpretation of the experimental data assumes that water flow between the split soil compartments does not occur. Another approach to investigate root water uptake is by numerical simulations combining soil and root water flow depending on the parameterization and description of the root system. Our aim is to demonstrate the synergisms that emerge from combining split root experiments with simulations. We show how growing root architectures derived from temporally repeated X-ray CT scanning can be implemented in numerical soil-plant models. Faba beans were grown with and without split layers and exposed to a single drought period during which plant and soil water status were measured. Root architectures were reconstructed from CT scans and used in the model R-SWMS (root-soil water movement and solute transport) to simulate water potentials in soil and roots in 3D as well as water uptake by growing roots in different depths. CT scans revealed that root development was considerably lower with split layers compared to without. This coincided with a reduction of transpiration, stomatal conductance and shoot growth. Simulated predawn water potentials were lower in the presence of split layers. Simulations showed that this was related to an increased resistance to vertical water flow in the soil by the split layers. Comparison between measured and simulated soil water potentials proved that the split layers were not perfectly isolating and that redistribution of water from the lower, wetter compartments to the drier upper compartments took place, thus water losses were not equal to the root water uptake from those compartments. Still, the layers increased the resistance to vertical flow which resulted in lower simulated collar water potentials that led to reduced stomatal conductance and growth. PMID

  4. Skeletal idiopathic osteosclerosis helps to perform personal identification of unknown decedents: A novel contribution from anatomical variants through CT scan.

    PubMed

    De Angelis, D; Gibelli, D; Palazzo, E; Sconfienza, L; Obertova, Z; Cattaneo, C

    2016-07-01

    Personal identification consists of the comparison of ante-mortem information from a missing person with post-mortem data obtained from an unidentified corpse. Such procedure is based on the assessment of individualizing features which may help in providing a conclusive identification between ante-mortem and post-mortem material. Anatomical variants may provide important clues to correctly identify human remains. Areas of idiopathic osteosclerosis (IO), or dense bone islands (DBIs) characterized by radiopaque areas of dense, trabeculated, non-inflamed vital bone represent one of these, potentially individualizing, anatomical features. This study presents a case where the finding of DBI was crucial for a positive identification through CT-scan. A decomposed body was found in an apartment in June 2014 in advanced decomposition and no dental records were available to perform a comparison for positive identification. Genetic tests were not applicable because of the lack of relatives in a direct line. The analysis of the only ante-mortem documentation, a CT-scan to the deceased dating back to August 2009, showed the presence of three DBIs within the trabecular bone of the proximal portion of the right femur. The same bony district was removed from the corpse during the autopsy and analysed by CT-scan, which verified the presence of the same features. Forensic practitioners should therefore be aware of the great importance of anatomical bone variants, such as dense bone islands for identification purposes, and the importance of advanced radiological technique for addressing the individualizing potential of such variants. We propose that anatomical variants of the human skeleton should be considered as being "primary identification characteristics" similar to dental status, fingerprints and DNA. PMID:27320398

  5. Skeletal idiopathic osteosclerosis helps to perform personal identification of unknown decedents: A novel contribution from anatomical variants through CT scan.

    PubMed

    De Angelis, D; Gibelli, D; Palazzo, E; Sconfienza, L; Obertova, Z; Cattaneo, C

    2016-07-01

    Personal identification consists of the comparison of ante-mortem information from a missing person with post-mortem data obtained from an unidentified corpse. Such procedure is based on the assessment of individualizing features which may help in providing a conclusive identification between ante-mortem and post-mortem material. Anatomical variants may provide important clues to correctly identify human remains. Areas of idiopathic osteosclerosis (IO), or dense bone islands (DBIs) characterized by radiopaque areas of dense, trabeculated, non-inflamed vital bone represent one of these, potentially individualizing, anatomical features. This study presents a case where the finding of DBI was crucial for a positive identification through CT-scan. A decomposed body was found in an apartment in June 2014 in advanced decomposition and no dental records were available to perform a comparison for positive identification. Genetic tests were not applicable because of the lack of relatives in a direct line. The analysis of the only ante-mortem documentation, a CT-scan to the deceased dating back to August 2009, showed the presence of three DBIs within the trabecular bone of the proximal portion of the right femur. The same bony district was removed from the corpse during the autopsy and analysed by CT-scan, which verified the presence of the same features. Forensic practitioners should therefore be aware of the great importance of anatomical bone variants, such as dense bone islands for identification purposes, and the importance of advanced radiological technique for addressing the individualizing potential of such variants. We propose that anatomical variants of the human skeleton should be considered as being "primary identification characteristics" similar to dental status, fingerprints and DNA.

  6. Radiation-induced osteosarcoma might mimic metastatic bone lesions: a case with bone scan and FDG PET/CT imaging.

    PubMed

    Koyama, Masamichi; Koizumi, Mitsuru; Umayahara, Kenji; Takeshima, Nobuhiro; Takahashi, Shunji

    2015-05-01

    We report on a 53-year-old woman with osteosarcoma of the skull who underwent radiation therapy for metastatic brain tumor. She had a history of uterine endometrial cancer treated with chemotherapy and surgery 9 years previously. FDG PET/CT for surveillance showed nodular accumulation at the right suprainguinal region and very avid accumulation at the left side of the occipital bone. Bone scan showed increased accumulation at the same portion of the occipital bone. The occipital tumor was surgically removed and diagnosed as radiation-induced osteosarcoma.

  7. Chemical imaging of single catalyst particles with scanning μ-XANES-CT and μ-XRF-CT.

    PubMed

    Price, S W T; Ignatyev, K; Geraki, K; Basham, M; Filik, J; Vo, N T; Witte, P T; Beale, A M; Mosselmans, J F W

    2015-01-01

    The physicochemical state of a catalyst is a key factor in determining both activity and selectivity; however these materials are often not structurally or compositionally homogeneous. Here we report on the 3-dimensional imaging of an industrial catalyst, Mo-promoted colloidal Pt supported on carbon. The distribution of both the active Pt species and Mo promoter have been mapped over a single particle of catalyst using microfocus X-ray fluorescence computed tomography. X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure revealed a mixed local coordination environment, including the presence of both metallic Pt clusters and Pt chloride species, but also no direct interaction between the catalyst and Mo promoter. We also report on the benefits of scanning μ-XANES computed tomography for chemical imaging, allowing for 2- and 3-dimensional mapping of the local electronic and geometric environment, in this instance for both the Pt catalyst and Mo promoter throughout the catalyst particle.

  8. 1975 Memorial Award Paper. Image generation and display techniques for CT scan data. Thin transverse and reconstructed coronal and sagittal planes.

    PubMed

    Glenn, W V; Johnston, R J; Morton, P E; Dwyer, S J

    1975-01-01

    The various limitations to computerized axial tomographic (CT) interpretation are due in part to the 8-13 mm standard tissue plane thickness and in part to the absence of alternative planes of view, such as coronal or sagittal images. This paper describes a method for gathering multiple overlapped 8 mm transverse sections, subjecting these data to a deconvolution process, and then displaying thin (1 mm) transverse as well as reconstructed coronal and sagittal CT images. Verification of the deconvolution technique with phantom experiments is described. Application of the phantom results to human post mortem CT scan data illustrates this method's faithful reconstruction of coronal and sagittal tissue densities when correlated with actual specimen photographs of a sectioned brain. A special CT procedure, limited basal overlap scanning, is proposed for use on current first generation CT scanners without hardware modification.

  9. Motion artifacts occurring at the lung/diaphragm interface using 4D CT attenuation correction of 4D PET scans.

    PubMed

    Killoran, Joseph H; Gerbaudo, Victor H; Mamede, Marcelo; Ionascu, Dan; Park, Sang-June; Berbeco, Ross

    2011-11-15

    For PET/CT, fast CT acquisition time can lead to errors in attenuation correction, particularly at the lung/diaphragm interface. Gated 4D PET can reduce motion artifacts, though residual artifacts may persist depending on the CT dataset used for attenuation correction. We performed phantom studies to evaluate 4D PET images of targets near a density interface using three different methods for attenuation correction: a single 3D CT (3D CTAC), an averaged 4D CT (CINE CTAC), and a fully phase matched 4D CT (4D CTAC). A phantom was designed with two density regions corresponding to diaphragm and lung. An 8 mL sphere phantom loaded with 18F-FDG was used to represent a lung tumor and background FDG included at an 8:1 ratio. Motion patterns of sin(x) and sin4(x) were used for dynamic studies. Image data was acquired using a GE Discovery DVCT-PET/CT scanner. Attenuation correction methods were compared based on normalized recovery coefficient (NRC), as well as a novel quantity "fixed activity volume" (FAV) introduced in our report. Image metrics were compared to those determined from a 3D PET scan with no motion present (3D STATIC). Values of FAV and NRC showed significant variation over the motion cycle when corrected by 3D CTAC images. 4D CTAC- and CINE CTAC-corrected PET images reduced these motion artifacts. The amount of artifact reduction is greater when the target is surrounded by lower density material and when motion was based on sin4(x). 4D CTAC reduced artifacts more than CINE CTAC for most scenarios. For a target surrounded by water equivalent material, there was no advantage to 4D CTAC over CINE CTAC when using the sin(x) motion pattern. Attenuation correction using both 4D CTAC or CINE CTAC can reduce motion artifacts in regions that include a tissue interface such as the lung/diaphragm border. 4D CTAC is more effective than CINE CTAC at reducing artifacts in some, but not all, scenarios.

  10. Impact of FDG-PET/CT Imaging on Nodal Staging for Head-And-Neck Squamous Cell Carcinoma

    SciTech Connect

    Murakami, Ryuji . E-mail: murakami@kaiju.medic.kumamoto-u.ac.jp; Uozumi, Hideaki; Hirai, Toshinori; Nishimura, Ryuichi; Shiraishi, Shinya; Ota, Kazutoshi D.D.S.; Murakami, Daizo; Tomiguchi, Seiji; Oya, Natsuo; Katsuragawa, Shigehiko; Yamashita, Yasuyuki

    2007-06-01

    Purpose: To evaluate the impact of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) imaging on nodal staging for head-and-neck squamous cell carcinoma (SCC). Methods and Materials: The study population consisted of 23 patients with head-and-neck SCC who were evaluated with FDG-PET/CT and went on to neck dissection. Two observers consensually determined the lesion size and maximum standardized uptake value (SUV{sub max}) and compared the results with pathologic findings on nodal-level involvement. Two different observers (A and B) independently performed three protocols for clinical nodal staging. Methods 1, 2, and 3 were based on conventional modalities, additional visual information from FDG-PET/CT images, and FDG-PET/CT imaging alone with SUV data, respectively. Results: All primary tumors were visualized with FDG-PET/CT. Pathologically, 19 positive and 93 negative nodal levels were identified. The SUV{sub max} overlapped in negative and positive nodes <15 mm in diameter. According to receiver operating characteristics analysis, the size-based SUV{sub max} cutoff values were 1.9, 2.5, and 3.0 for lymph nodes <10 mm, 10-15 mm, and >15 mm, respectively. These cutoff values yielded 79% sensitivity and 99% specificity for nodal-level staging. For Observer A, the sensitivity and specificity in Methods 1, 2, and 3 were 68% and 94%, 68% and 99%, and 84% and 99%, respectively, and Method 3 yielded significantly higher accuracy than Method 1 (p = 0.0269). For Observer B, Method 3 yielded the highest sensitivity (84%) and specificity (99%); however, the difference among the three protocols was not statistically significant. Conclusion: Imaging with FDG-PET/CT with size-based SUV{sub max} cutoff values is an important modality for radiation therapy planning.

  11. Radiofrequency Ablation Assisted by Real-Time Virtual Sonography and CT for Hepatocellular Carcinoma Undetectable by Conventional Sonography

    SciTech Connect

    Nakai, Motoki Sato, Morio; Sahara, Shinya; Takasaka, Isao; Kawai, Nobuyuki; Minamiguchi, Hiroki; Tanihata, Hirohiko; Kimura, Masashi; Takeuchi, Nozomu

    2009-01-15

    Real-time virtual sonography (RVS) is a diagnostic imaging support system, which provides the same cross-sectional multiplanar reconstruction images as ultrasound images on the same monitor screen in real time. The purpose of this study was to evaluate radiofrequency ablation (RFA) assisted by RVS and CT for hepatocellular carcinoma (HCC) undetectable with conventional sonography. Subjects were 20 patients with 20 HCC nodules not detected by conventional sonography but detectable by CT or MRI. All patients had hepatitis C-induced liver cirrhosis; there were 13 males and 7 females aged 55-81 years (mean, 69.3 years). RFA was performed in the CT room, and the tumor was punctured with the assistance of RVS. CT was performed immediately after puncture, and ablation was performed after confirming that the needle had been inserted into the tumor precisely. The mean number of punctures and success rates of the first puncture were evaluated. Treatment effects were evaluated with dynamic CT every 3 months after RFA. RFA was technically feasible and local tumor control was achieved in all patients. The mean number of punctures was 1.1, and the success rate of the first puncture was 90.0%. This method enabled safe ablation without complications. The mean follow-up period was 13.5 month (range, 9-18 months). No local recurrence was observed at the follow-up points. In conclusion, RFA assisted by RVS and CT is a safe and efficacious method of treatment for HCC undetectable by conventional sonography.

  12. Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France

    PubMed Central

    Journy, N; Rehel, J-L; Ducou Le Pointe, H; Lee, C; Brisse, H; Chateil, J-F; Caer-Lorho, S; Laurier, D; Bernier, M-O

    2015-01-01

    Background: Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk. Methods: The cohort included 67 274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses. Results: During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures. Conclusions: This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans. PMID:25314057

  13. Chondroitin sulfate iron colloid-enhanced MR imaging in patients with hepatocellular carcinoma. Comparison with CT during arterial portography.

    PubMed

    Kamba, M; Suto, Y; Kato, T

    1994-11-01

    Chondroitin sulfate iron colloid (CSIC) was used as an MR contrast agent for the detection of hepatocellular carcinoma (HCC). The findings of 25 surgically confirmed HCCs in 19 patients were retrospectively analyzed. T1-, T2- and proton density-weighted spin echo MR images were obtained before and after i.v. injection of 23.6 microM Fe/kg of CSIC. Unenhanced and CSIC-enhanced MR images and images obtained by CT during arterial portography (CT-AP) were correlated with surgical pathology findings. The sensitivities of CSIC-enhanced and unenhanced MR imaging, and CT-AP were 92%, 80%, and 88%, respectively. No significant differences were noted. Portal flow abnormalities demonstrated by CT-AP did not affect the detection of HCC by CSIC-enhanced MR imaging. CSIC-enhancement at MR imaging was a disadvantage in the detection of lesions less than 1 cm in diameter. CSIC-enhanced MR imaging is a supplemental method for the detection of HCC.

  14. [Bone scanning with sodium 18F-fluoride PET and PET/CT. German guideline Version 1.0.].

    PubMed

    Hellwig, D; Krause, B-J; Schirrmeister, H; Freesmeyer, M

    2010-01-01

    In nuclear medicine, bone scanning is based on the principle of scintigraphy using bone-seeking radiopharmaceuticals which accumulate in sites of increased bone formation. From a historical point of view, (18)F-fluoride was one of the first osteotropic tracers which was replaced by (99m)Tc-labelled polyphosphonates. With the development of modern PET equipment the superior diagnostic performance of (18)F-fluoride PET for the detection and characterization of osseous lesions was proven in comparison to conventional bone scanning. Recently, its importance as a substitute of conventional skeletal scintigraphy increased in a time with limited availability of (99)Mo/(99m)Tc. To ensure health care during this period, (18)F-fluoride PET currently became part of common outpatient care. This guideline comprehends recommendations on indications, protocols, interpretation and reporting of (18)F-fluoride PET and PET/CT. PMID:20838734

  15. Segmentation of pulmonary nodules in three-dimensional CT images by use of a spiral-scanning technique

    SciTech Connect

    Wang Jiahui; Engelmann, Roger; Li Qiang

    2007-12-15

    Accurate segmentation of pulmonary nodules in computed tomography (CT) is an important and difficult task for computer-aided diagnosis of lung cancer. Therefore, the authors developed a novel automated method for accurate segmentation of nodules in three-dimensional (3D) CT. First, a volume of interest (VOI) was determined at the location of a nodule. To simplify nodule segmentation, the 3D VOI was transformed into a two-dimensional (2D) image by use of a key 'spiral-scanning' technique, in which a number of radial lines originating from the center of the VOI spirally scanned the VOI from the 'north pole' to the 'south pole'. The voxels scanned by the radial lines provided a transformed 2D image. Because the surface of a nodule in the 3D image became a curve in the transformed 2D image, the spiral-scanning technique considerably simplified the segmentation method and enabled reliable segmentation results to be obtained. A dynamic programming technique was employed to delineate the 'optimal' outline of a nodule in the 2D image, which corresponded to the surface of the nodule in the 3D image. The optimal outline was then transformed back into 3D image space to provide the surface of the nodule. An overlap between nodule regions provided by computer and by the radiologists was employed as a performance metric for evaluating the segmentation method. The database included two Lung Imaging Database Consortium (LIDC) data sets that contained 23 and 86 CT scans, respectively, with 23 and 73 nodules that were 3 mm or larger in diameter. For the two data sets, six and four radiologists manually delineated the outlines of the nodules as reference standards in a performance evaluation for nodule segmentation. The segmentation method was trained on the first and was tested on the second LIDC data sets. The mean overlap values were 66% and 64% for the nodules in the first and second LIDC data sets, respectively, which represented a higher performance level than those of two

  16. Automated bone removal in CT angiography: Comparison of methods based on single energy and dual energy scans

    SciTech Connect

    Straten, Marcel van; Schaap, Michiel; Dijkshoorn, Marcel L.; Greuter, Marcel J.; Lugt, Aad van der; Krestin, Gabriel P.; Niessen, Wiro J.

    2011-11-15

    Purpose: To evaluate dual energy based methods for bone removal in computed tomography angiography (CTA) images and compare these with single energy based methods that use an additional, nonenhanced, CT scan. Methods: Four different bone removal methods were applied to CT scans of an anthropomorphic thorax phantom, acquired with a second generation dual source CT scanner. The methods differed by the way information on the presence of bone was obtained (either by using an additional, nonenhanced scan or by scanning with two tube voltages at the same time) and by the way the bone was removed from the CTA images (either by masking or subtracting the bone). The phantom contained parts which mimic vessels of various diameters in direct contact with bone. Both a quantitative and qualitative analysis of image quality after bone removal was performed. Image quality was quantified by the contrast-to-noise ratio (CNR) normalized to the square root of the dose (CNRD). At locations where vessels touch bone, the quality of the bone removal and the vessel preservation were visually assessed. The dual energy based methods were assessed with and without the addition of a 0.4 mm tin filter to the high voltage x-ray tube filtration. For each bone removal method, the dose required to obtain a certain CNR after bone removal was compared with the dose of a reference scan with the same CNR but without automated bone removal. The CNRD value of the reference scan was maximized by choosing the lowest tube voltage available. Results: All methods removed the bone completely. CNRD values were higher for the masking based methods than for the subtraction based methods. Single energy based methods had a higher CNRD value than the corresponding dual energy based methods. For the subtraction based dual energy method, tin filtration improved the CNRD value with approximately 50%. For the masking based dual energy method, it was easier to differentiate between iodine and bone when tin filtration

  17. Analytic image reconstruction from partial data for a single-scan cone-beam CT with scatter correction

    SciTech Connect

    Min, Jonghwan; Pua, Rizza; Cho, Seungryong; Kim, Insoo; Han, Bumsoo

    2015-11-15

    Purpose: A beam-blocker composed of multiple strips is a useful gadget for scatter correction and/or for dose reduction in cone-beam CT (CBCT). However, the use of such a beam-blocker would yield cone-beam data that can be challenging for accurate image reconstruction from a single scan in the filtered-backprojection framework. The focus of the work was to develop an analytic image reconstruction method for CBCT that can be directly applied to partially blocked cone-beam data in conjunction with the scatter correction. Methods: The authors developed a rebinned backprojection-filteration (BPF) algorithm for reconstructing images from the partially blocked cone-beam data in a circular scan. The authors also proposed a beam-blocking geometry considering data redundancy such that an efficient scatter estimate can be acquired and sufficient data for BPF image reconstruction can be secured at the same time from a single scan without using any blocker motion. Additionally, scatter correction method and noise reduction scheme have been developed. The authors have performed both simulation and experimental studies to validate the rebinned BPF algorithm for image reconstruction from partially blocked cone-beam data. Quantitative evaluations of the reconstructed image quality were performed in the experimental studies. Results: The simulation study revealed that the developed reconstruction algorithm successfully reconstructs the images from the partial cone-beam data. In the experimental study, the proposed method effectively corrected for the scatter in each projection and reconstructed scatter-corrected images from a single scan. Reduction of cupping artifacts and an enhancement of the image contrast have been demonstrated. The image contrast has increased by a factor of about 2, and the image accuracy in terms of root-mean-square-error with respect to the fan-beam CT image has increased by more than 30%. Conclusions: The authors have successfully demonstrated that the

  18. Micro-CT scan reveals an unexpected high-volume and interconnected pore network in a Cretaceous Sanagasta dinosaur eggshell.

    PubMed

    Hechenleitner, E Martín; Grellet-Tinner, Gerald; Foley, Matthew; Fiorelli, Lucas E; Thompson, Michael B

    2016-03-01

    The Cretaceous Sanagasta neosauropod nesting site (La Rioja, Argentina) was the first confirmed instance of extinct dinosaurs using geothermal-generated heat to incubate their eggs. The nesting strategy and hydrothermal activities at this site led to the conclusion that the surprisingly 7 mm thick-shelled eggs were adapted to harsh hydrothermal microenvironments. We used micro-CT scans in this study to obtain the first three-dimensional microcharacterization of these eggshells. Micro-CT-based analyses provide a robust assessment of gas conductance in fossil dinosaur eggshells with complex pore canal systems, allowing calculation, for the first time, of the shell conductance through its thickness. This novel approach suggests that the shell conductance could have risen during incubation to seven times more than previously estimated as the eggshell erodes. In addition, micro-CT observations reveal that the constant widening and branching of pore canals form a complex funnel-like pore canal system. Furthermore, the high density of pore canals and the presence of a lateral canal network in the shell reduce the risks of pore obstruction during the extended incubation of these eggs in a relatively highly humid and muddy nesting environment. PMID:27009182

  19. A pulmonary chondromatous hamartoma resembling multiple metastases in the (18)F-FDG PET/CT scan.

    PubMed

    Li, Li; Jiang, Chong; Tian, Rong

    2016-01-01

    Multiple pulmonary hamartomas (PH) occur rarely, are mostly seen in females, and are usually leiomyomatous hamartomas. Here, we report an extremely rare case of a 30 years old male patient diagnosed as multiple pulmonary chondromatous hamartomas. He was admitted on May 2015 to our hospital for a 3 months history of cough. Multiple nodules in the right lung were detected on chest X-rays during a routine checkup 9 months ago and in a subsequent chest computed tomography (CT). However, he abandoned medical follow-up because he was asymptomatic. Nine months later, rare and atypical CT findings with progression were observed during this visit so that pulmonary metastases from an unknown primary tumor was suspected. Positron emission tomography/computed tomography (PET/CT) scan showed mild fluorine-18 fluorodeoxyglucose ((18)F-FDG) uptake in the lesions and no abnormal foci in any other part of his body. A posterolateral thoracotomy was performed. Pathologic features were consistent with those of pulmonary chondromatous hamartomas. PMID:27331216

  20. A novel spherical shell filter for reducing false positives in automatic detection of pulmonary nodules in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    van de Leemput, Sil; Dorssers, Frank; Ehteshami Bejnordi, Babak

    2015-03-01

    Early detection of pulmonary nodules is crucial for improving prognosis of patients with lung cancer. Computer-aided detection of lung nodules in thoracic computed tomography (CT) scans has a great potential to enhance the performance of the radiologist in detecting nodules. In this paper we present a computer-aided lung nodule detection system for computed tomography (CT) scans that works in three steps. The system first segments the lung using thresholding and hole filling. From this segmentation the system extracts candidate nodules using Laplacian of Gaussian. To reject false positives among the detected candidate nodules, multiple established features are calculated. We propose a novel feature based on a spherical shell filter, which is specifically designed to distinguish between vascular structures and nodular structures. The performance of the proposed CAD system was evaluated by partaking in the ANODE09 challenge, which presents a platform for comparing automatic nodule detection programs. The results from the challenge show that our CAD system ranks third among the submitted works, demonstrating the efficacy of our proposed CAD system. The results also show that our proposed spherical shell filter in combination with conventional features can significantly reduce the number of false positives from the detected candidate nodules.

  1. Automated segmentation of the thyroid gland on thoracic CT scans by multiatlas label fusion and random forest classification.

    PubMed

    Narayanan, Divya; Liu, Jiamin; Kim, Lauren; Chang, Kevin W; Lu, Le; Yao, Jianhua; Turkbey, Evrim B; Summers, Ronald M

    2015-10-01

    The thyroid is an endocrine gland that regulates metabolism. Thyroid image analysis plays an important role in both diagnostic radiology and radiation oncology treatment planning. Low tissue contrast of the thyroid relative to surrounding anatomic structures makes manual segmentation of this organ challenging. This work proposes a fully automated system for thyroid segmentation on CT imaging. Following initial thyroid segmentation with multiatlas joint label fusion, a random forest (RF) algorithm was applied. Multiatlas label fusion transfers labels from labeled atlases and warps them to target images using deformable registration. A consensus atlas solution was formed based on optimal weighting of atlases and similarity to a given target image. Following the initial segmentation, a trained RF classifier employed voxel scanning to assign class-conditional probabilities to the voxels in the target image. Thyroid voxels were categorized with positive labels and nonthyroid voxels were categorized with negative labels. Our method was evaluated on CT scans from 66 patients, 6 of which served as atlases for multiatlas label fusion. The system with independent multiatlas label fusion method and RF classifier achieved average dice similarity coefficients of [Formula: see text] and [Formula: see text], respectively. The system with sequential multiatlas label fusion followed by RF correction increased the dice similarity coefficient to [Formula: see text] and improved the segmentation accuracy.

  2. [Epidemiological aspects of stroke in CT-scan department of the Point-G Hospital in Bamako, Mali].

    PubMed

    Keita, A D; Toure, M; Diawara, A; Coulibaly, Y; Doumbia, S; Kane, M; Doumbia, D; Sidibe, S; Traore, I

    2005-11-01

    The purpose of this prospective study conducted between January 2000 and December 2001 was to identify tomodensitometric aspects of stroke. The relationship between lesion type (hemorrhagic, ischemic, and transient ischemic) and prognosis was assessed. Axial sections were made through the posterior fossa (5 mm at 5mm intervals) and subtentorial region (10 mm at 10 mm intervals). The Virchow plan was used as the reference for sections. The chi square test was used to evaluate the correlation between lesion type and prognosis. A total of 159 stroke patients with a mean age of 44.5 years were enrolled during the study period. There were 90 men (56.6%) and 69 women (43.3%). In 118 patients (74.2%), CT scans showed cerebral abnormalities including ischemic lesions in 71 (44.6%) and hemorrhagic lesions in 47 (29.6%). Overall mortality was 45.7% (54/118). Hemorrhagic lesions were fatal in 51.1% (24/47) of cases and ischemic lesions in 35.2% (25/71). Transitory ischemic accidents were fatal in 0.12% of cases (5/41). This study demonstrates that CT scan is an important tool for stroke management by identifying the type and location of lesions.

  3. CT scanning analysis of Megantereon whitei (Carnivora, Machairodontinae) from Monte Argentario (Early Pleistocene, central Italy): evidence of atavistic teeth

    NASA Astrophysics Data System (ADS)

    Iurino, Dawid Adam; Sardella, Raffaele

    2014-12-01

    CT scanning analysis applied to vertebrate palaeontology is providing an increasing number of data of great interest. This method can be used in many branches of palaeontology such as the investigation of all the fossilized elements in a hard matrix and the hidden structures in the bones. A large number of pathologies are "hidden", completely or partially invisible on the external surface of the bones because their development took place within the bones. However, the study of these diseases and abnormalities plays a crucial role in our understanding of evolutionary and adaptive processes of extinct taxa. The analysis of a partial skeleton of the sabre-toothed felid Megantereon whitei from the Early Pleistocene karst filling deposits of Monte Argentario (Tuscany, Italy) has been carried out. The CT scanning analysis put in evidence the presence of supernumerary teeth (P2) and the absence of P3 in the mandible. The occurrence of P2 can be considered as an evidence of atavism. Such an archaic feature is recorded for the first time in Megantereon.

  4. CT scans and 3D reconstructions of Florida manatee (Trichechus manatus latirostris) heads and ear bones.

    PubMed

    Chapla, Marie E; Nowacek, Douglas P; Rommel, Sentiel A; Sadler, Valerie M

    2007-06-01

    The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee's fatty tissue was significantly less dense than the other soft tissues within the head (p<0.05). The squamosal bone was significantly less dense than the other bones of the head (p<0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex.

  5. CT scans and 3D reconstructions of Florida manatee (Trichechus manatus latirostris) heads and ear bones.

    PubMed

    Chapla, Marie E; Nowacek, Douglas P; Rommel, Sentiel A; Sadler, Valerie M

    2007-06-01

    The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee's fatty tissue was significantly less dense than the other soft tissues within the head (p<0.05). The squamosal bone was significantly less dense than the other bones of the head (p<0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex. PMID:17420106

  6. Anatomical database generation for radiation transport modeling from computed tomography (CT) scan data

    SciTech Connect

    Margle, S.M.; Tinnel, E.P.; Till, L.E.; Eckerman, K.F.; Durfee, R.C.

    1989-01-01

    Geometric models of the anatomy are used routinely in calculations of the radiation dose in organs and tissues of the body. Development of such models has been hampered by lack of detailed anatomical information on children, and models themselves have been limited to quadratic conic sections. This summary reviews the development of an image processing workstation used to extract anatomical information from routine diagnostic CT procedure. A standard IBM PC/AT microcomputer has been augmented with an automatically loading 9-track magnetic tape drive, an 8-bit 1024 {times} 1024 pixel graphics adapter/monitor/film recording package, a mouse/trackball assembly, dual 20 MB removable cartridge media, a 72 MB disk drive, and a printer. Software utilized by the workstation includes a Geographic Information System (modified for manipulation of CT images), CAD software, imaging software, and various modules to ease data transfer among the software packages. 5 refs., 3 figs.

  7. Reproducibility and Reliability of Anti-3-[18F] FACBC Uptake Measurements in Background Structures and Malignant Lesions on Follow-Up PET-CT in Prostate Carcinoma: an Exploratory Analysis

    PubMed Central

    Odewole, Oluwaseun A.; Oyenuga, Oyeladun A.; Tade, Funmilayo; Savir-Baruch, Bital; Nieh, Peter T.; Master, Viraj; Chen, Zhengjia; Wang, Xiaojing; Jani, Ashesh B.; Bellamy, Leah M.; Halkar, Raghuveer K.; Goodman, Mark M.; Schuster, David M.

    2016-01-01

    Purpose The aim of this study is to examine the reproducibility of anti-1-amino-3-[18F]fluorocyclobutane-1-carboxylic acid (anti-3-[18F]FACBC) quantitative measurements in key background structures and untreated malignant lesions. Procedures Retrospective review of 14 patients who underwent follow-up anti-3-[18F]FACBC positron emission tomography-X-ray computed tomography (PET-CT) for prostate carcinoma recurrence. Standard uptake values (SUV) were measured in both original and follow-up scans in key background structures and untreated malignant lesions. Absolute and percent mean difference in SUV between scans and interclass correlation coefficients (ICC) were also computed. Results Mean (±SD, range) scan interval was 17.4 months (±7.1, 4–29). %Mean difference in SUVmean was <20 % in background structures with low absolute differences. ICCs were >0.6 except for early-phase blood pool (ICC=0.4). SUVmax in malignant lesions without interim therapy increased or remained stable over time. Conclusions Despite variable time interval between scans, FACBC PET-CT demonstrates acceptable reproducibility in key background structures. Untreated malignant lesions showed stable or increased uptake over time. A formal test-retest study is planned. PMID:25281411

  8. Detection of Recurrent Prostate Carcinoma with anti-1-Amino-3-18F-Fluorocyclobutane-1-Carboxylic Acid PET/CT and 111In–Capromab Pendetide SPECT/CT

    PubMed Central

    Savir-Baruch, Bital; Nieh, Peter T.; Master, Viraj A.; Halkar, Raghuveer K.; Rossi, Peter J.; Lewis, Melinda M.; Nye, Jonathon A.; Yu, Weiping; Bowman, F. DuBois; Goodman, Mark M.

    2011-01-01

    Purpose: To compare the diagnostic performance of the synthetic amino acid analog radiotracer anti-1-amino-3-fluorine 18-fluorocyclobutane-1-carboxylic acid (anti-3-18F-FACBC) with that of indium 111 (111In)–capromab pendetide in the detection of recurrent prostate carcinoma. Materials and Methods: This prospective study was approved by the institutional review board and complied with HIPAA guidelines. Written informed consent was obtained. Fifty patients (mean age, 68.3 years ± 8.1 [standard deviation]; age range, 50–90 years) were included in the study on the basis of the following criteria: (a) Recurrence of prostate carcinoma was suspected after definitive therapy for localized disease, (b) bone scans were negative, and (c) anti-3-18F-FACBC positron emission tomography (PET)/computed tomography (CT) and 111In–capromab pendetide single photon emission computed tomography (SPECT)/CT were performed within 6 weeks of each other. Studies were evaluated by two experienced interpreters for abnormal uptake suspicious for recurrent disease in the prostate bed and extraprostatic locations. The reference standard was a combination of tissue correlation, imaging, laboratory, and clinical data. Diagnostic performance measures were calculated and tests of the statistical significance of differences determined by using the McNemar χ2 test as well as approximate tests based on the difference between two proportions. Results: For disease detection in the prostate bed, anti-3-18F-FACBC had a sensitivity of 89% (32 of 36 patients; 95% confidence interval [CI]: 74%, 97%), specificity of 67% (eight of 12 patients; 95% CI: 35%, 90%), and accuracy of 83% (40 of 48 patients; 95% CI: 70%, 93%). 111In–capromab pendetide had a sensitivity of 69% (25 of 36 patients; 95% CI: 52%, 84%), specificity of 58% (seven of 12 patients; 95% CI: 28%, 85%), and accuracy of 67% (32 of 48 patients; 95% CI: 52%, 80%). In the detection of extraprostatic recurrence, anti-3-18F-FACBC had a

  9. Panel Reviews Benefits and Harms of CT Scans for Lung Cancer Screening | Division of Cancer Prevention

    Cancer.gov

    A panel of experts has reviewed the evidence regarding the benefits and harms of screening for lung cancer with low-dose computed tomography (CT) and concluded that the technology may benefit some individuals at high risk for lung cancer. But the panel cautioned that many questions remain about the potential harms of screening and how to translate screening into clinical practice. |

  10. Renal Sympathetic Denervation by CT-scan-Guided Periarterial Ethanol Injection in Sheep

    SciTech Connect

    Firouznia, Kavous Hosseininasab, Sayed jaber; Amanpour, Saeid; Haj-Mirzaian, Arya; Miri, Roza; Muhammadnejad, Ahad; Muhammadnejad, Samad; Jalali, Amir H.; Ahmadi, Farrokhlagha; Rokni-Yazdi, Hadi

    2015-08-15

    BackgroundRenal nerves are a recent target in the treatment of hypertension. Renal sympathetic denervation (RSD) is currently performed using catheter-based radiofrequency ablation (RFA) and because this method has limitations, percutaneous magnetic resonance (MR)-guided periarterial ethanol injection is a suggested alternative. However, few studies have been conducted on the effectiveness of percutaneous ethanol injection for RSD.AimTo evaluate the feasibility, efficacy, and complications of computed tomography (CT)-guided periarterial ethanol injection.MethodsEthanol (10 ml, 99.6 %) was injected around the right renal artery in six sheep under CT guidance with the left kidney serving as a control. Before and after the intervention, the sheep underwent MR imaging studies and the serum creatinine level was measured. One month after the intervention, the sheep were euthanized and norepinephrine (NE) concentration in the renal parenchyma was measured to evaluate the efficacy of the procedure. The treated tissues were also examined histopathologically to evaluate vascular, parenchymal, and neural injury.ResultsThe right kidney parenchymal NE concentration decreased significantly compared with the left kidney after intervention (average reduction: 40 %, P = 0.0016). Histologic examination revealed apparent denervation with no other vascular or parenchymal injuries observed in the histological and imaging studies.ConclusionEffective and feasible RSD was achieved using CT-guided periarterial ethanol injection. This technique may be a potential alternative to catheter-based RFA in the treatment of hypertension.

  11. MO-C-18C-01: Radiation Risks at Level of Few CT Scans: How Real?- Science to Practice

    SciTech Connect

    Rehani, M; Samei, E; Morgan, W; Goske, M; Shore, R

    2014-06-15

    There are controversies surrounding radiation effects in human population in the range of radiation doses encountered by patients resulting from one to several CT scans. While it is understandable why the effects from low levels of diagnostic radiation are controversial, the situation is complicated by the media which may distort the known facts. There is need to understand the state of science regarding low-level radiation effects and also to understand how to communicate the potential risk with patients, the public and media. This session will seek to come to a consensus in order to speak with one voice to the media and the public. This session will review radiation effects known so far from a variety of exposed groups since the nuclear holocaust, provide clarification where effects are certain and where they are not, at what level extrapolation is the only way and at what level there is weak but agreeable acceptance. We will depict where and why there is agreement among organizations responsible for studying radiation effects, and how to deal with situations where effects are uncertain. Specific focus on radiation effects in children will be provided.Finally, the session will attempt to bridge the communication gap from the science to how to be an effective communicator with patients, parents, and media about ionizing radiation. Learning Objectives: To have a clear understanding about certainties and uncertainties of radiation effects at the level of a few CT scans To understand the results and limitations from 3 major pediatric CT scientific studies on childhood exposures published recently. To understand successful strategies used in risk communication.

  12. 3D stereophotogrammetric image superimposition onto 3D CT scan images: the future of orthognathic surgery. A pilot study.

    PubMed

    Khambay, Balvinder; Nebel, Jean-Christophe; Bowman, Janet; Walker, Fraser; Hadley, Donald M; Ayoub, Ashraf

    2002-01-01

    The aim of this study was to register and assess the accuracy of the superimposition method of a 3-dimensional (3D) soft tissue stereophotogrammetric image (C3D image) and a 3D image of the underlying skeletal tissue acquired by 3D spiral computerized tomography (CT). The study was conducted on a model head, in which an intact human skull was embedded with an overlying latex mask that reproduced anatomic features of a human face. Ten artificial radiopaque landmarks were secured to the surface of the latex mask. A stereophotogrammetric image of the mask and a 3D spiral CT image of the model head were captured. The C3D image and the CT images were registered for superimposition by 3 different methods: Procrustes superimposition using artificial landmarks, Procrustes analysis using anatomic landmarks, and partial Procrustes analysis using anatomic landmarks and then registration completion by HICP (a modified Iterative Closest Point algorithm) using a specified region of both images. The results showed that Procrustes superimposition using the artificial landmarks produced an error of superimposition on the order of 10 mm. Procrustes analysis using anatomic landmarks produced an error in the order of 2 mm. Partial Procrustes analysis using anatomic landmarks followed by HICP produced a superimposition accuracy of between 1.25 and 1.5 mm. It was concluded that a stereophotogrammetric and a 3D spiral CT scan image can be superimposed with an accuracy of between 1.25 and 1.5 mm using partial Procrustes analysis based on anatomic landmarks and then registration completion by HICP.

  13. [Evaluation of resolving power property to the position and direction of in-plane in CT-scan system].

    PubMed

    Hara, Takanori; Ichikawa, Katsuhiro; Niwa, Shinji

    2008-01-20

    Analysis of the detailed physical property in CT system is important in an understanding of a clinical image. In this study, we evaluated resolution power property about the positions and direction for in-plane in CT system. The indexes of the resolving power property of CT images were measured by MTFs using the thin metal wire (diameter of 0.2 mm). We measured the positions of the iso-center and the off-center (32 mm, 64 mm, 96 mm, 128 mm) in in-plane. One-dimensional MTFs for the X-direction and Y-direction were calculated by the numerical slit scanning method. Then, MTF was calculated from the corresponding direction. As a result, when a filter kernel of high resolutions (B70) is used in the position of 128 mm, the resolution of X-direction was inferior to the Y-direction about 30% (at the MTF-value of 0.5 cycles/mm). Moreover, the resolution of X-direction at the position of 128 mm was inferior to the center about 33% (at the MTF-value of 0.5 cycles/mm). The resolving power property of in-plane in CT system was decreased in the calculation from the numerical slit that becomes perpendicular to the direction of centrifugal and, decreased proportionately with the distance from the center. Also, the resolutions along the centrifugal direction fell off remarkably at the peripheral area. And also, it turned out that the declining trend becomes larger, when the filter function for high-resolving power that is adapted for lungs is used.

  14. An accurate scatter measurement and correction technique for cone beam breast CT imaging using scanning sampled measurement (SSM)technique

    NASA Astrophysics Data System (ADS)

    Liu, Xinming; Shaw, Chris C.; Wang, Tianpeng; Chen, Lingyun; Altunbas, Mustafa C.; Kappadath, S. Cheenu

    2006-03-01

    We developed and investigated a scanning sampled measurement (SSM) technique for scatter measurement and correction in cone beam breast CT imaging. A cylindrical polypropylene phantom (water equivalent) was mounted on a rotating table in a stationary gantry experimental cone beam breast CT imaging system. A 2-D array of lead beads, with the beads set apart about ~1 cm from each other and slightly tilted vertically, was placed between the object and x-ray source. A series of projection images were acquired as the phantom is rotated 1 degree per projection view and the lead beads array shifted vertically from one projection view to the next. A series of lead bars were also placed at the phantom edge to produce better scatter estimation across the phantom edges. Image signals in the lead beads/bars shadow were used to obtain sampled scatter measurements which were then interpolated to form an estimated scatter distribution across the projection images. The image data behind the lead bead/bar shadows were restored by interpolating image data from two adjacent projection views to form beam-block free projection images. The estimated scatter distribution was then subtracted from the corresponding restored projection image to obtain the scatter removed projection images. Our preliminary experiment has demonstrated that it is feasible to implement SSM technique for scatter estimation and correction for cone beam breast CT imaging. Scatter correction was successfully performed on all projection images using scatter distribution interpolated from SSM and restored projection image data. The resultant scatter corrected projection image data resulted in elevated CT number and largely reduced the cupping effects.

  15. Radiofrequency Ablation of Non-Small-Cell Carcinoma of the Lung Under Real-Time FDG PET CT Guidance

    SciTech Connect

    Schoellnast, Helmut; Larson, Steven M.; Nehmeh, Sadek A.; Carrasquillo, Jorge A.; Thornton, Raymond H.; Solomon, Stephen B.

    2011-02-15

    Radiofrequency ablation (RFA) is a well-established method in treatment of patients with lung carcinomas who are not candidates for surgical resection. Usually computed tomographic (CT) guidance is used for the procedure, thus enabling needle placement and permitting evaluation of complications such as pneumothorax and bleeding. {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is generally used for tumor activity assessment and is therefore useful in follow-up after tumor treatment. A method that provides real-time image-based monitoring of RFA to ensure complete tumor ablation would be a valuable tool. In this report, we describe the behavior of preinjected FDG during PET CT-guided RFA of a non-small-cell lung carcinoma and discuss the value of FDG as a tool to provide intraprocedure monitor ablation. The size and the form of the activity changed during ablation. Ablation led to increase of the size and blurring and irregularity of the contour compared to pretreatment imaging. The maximal standardized uptake value decreased only slightly during the procedure. Therefore, before RFA, FDG PET can guide initial needle placement, but it does not serve as a monitoring tool to evaluate residual viable tissue during the procedure.

  16. A comparison of the psychological burden of PET/MRI and PET/CT scans and association to initial state anxiety and previous imaging experiences

    PubMed Central

    Neriman, D; Hoath, J; Millner, L; Endozo, R; Azzopardi, G; O'Meara, C; Bomanji, J; Groves, A M

    2015-01-01

    Objective: To investigate the level of psychological burden experienced by patients undergoing positron emission tomography (PET)/MRI scanning compared with PET/CT. Methods: 100 adult patients referred for PET/CT and underwent PET/MRI scanning were eligible. Initial state, psychological burden of PET/CT and PET/MRI, scan satisfaction and preference were assessed using a purpose-designed questionnaire, comprising 61 five-point Likert scale questions and a three-point tick box question indicating preference between PET/CT and PET/MRI. State anxiety was assessed using the state portion of the State Trait Anxiety Inventory. Wilcoxon signed-rank tests compared psychological burden experienced by participants following PET/CT and PET/MRI scan. Results: A greater level of psychological burden was experienced by patients during PET/MRI than PET/CT p ≤ 0.001, consistent with patients' preference for PET/CT over PET/MRI (p = 0.013). There was a significant relationship between PET/CT psychological burden and initial state (r = 0.386, p ≤ 0.001). No significant relationship was identified between Initial state and psychological burden of PET MRI (r = −0.089; p = 217). There was a significant relationship between psychological burden of PET/CT and PET/MRI (r = 0.354; p = 0.001). Conclusion: Patients' experience increased psychological burden during PET/MRI compared with PET/CT. Previous scanning experiences and patients' interactions prior to and during PET/MRI improved patient satisfaction. Interventions could be implemented to improve imaging outcome. Advances in knowledge: This study provides evidence for the increased psychological burden of PET/MRI compared with PET/CT, and that people prefer the PET/CT procedure. We have shown that the patients who expressed a preference for PET/MRI demonstrated significantly lower psychological burden for that procedure than those that preferred PET/CT, which indicates that the benefit of reduced

  17. Value of fourth and subsequent post-therapy follow-up 18F-FDG PET/CT scans in patients with breast cancer

    PubMed Central

    Taghipour, Mehdi; Sheikhbahaei, Sara; Trahan, Tyler J.; Subramaniam, Rathan M.

    2016-01-01

    Objective To evaluate the accuracy and value of the fourth and subsequent post-therapy follow-up fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) scans in the clinical assessment of breast cancer patients. Materials and methods Ninety-two female patients, with a total of 426 fourth and subsequent follow-up PET/CT scans, were retrospectively included. Patients were followed for a median of 23.7 months (range, 0.7–124.4) from the fourth follow-up PET/CT. The diagnostic accuracy of PET/CT, its impact on clinical assessment, patients’ management, and survival outcome were established. Result Of the 426 follow-up PET/CT scans, 264 (62%) were interpreted as positive and 162 (38%) were interpreted as negative. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the fourth and subsequent follow-up PET/CT scans were 97.7, 98.1, 98.8, 96.3, and 97.9%, respectively. Fourth and subsequent follow-up PET/CT were useful in excluding a tumor in 13.4% (39/292) of patients with a clinical suspicion of recurrence and identifying suspected recurrence in 10.5% (14/134) of patients without previous clinical suspicion. A change in management was noted in 6.7% (9/134) of scan times when the scans were performed without previous clinical suspicion of recurrence or therapy response and was 27.7% (81/292) when the scans were performed with clinical suspicion. Overall survival differed significantly between patients with all negative follow-up scans (n = 23) and those who had at least one positive follow-up scan (n = 69) (hazard ratio of 4.65, P < 0.001). Conclusion The fourth and subsequent PET/CT scans performed after the completion of primary treatment led to a change in management in 27.7% of patients when the scans were performed with clinical suspicion and only in 6.7% of patients when performed without clinical suspicion or context. PMID:27110955

  18. Pediatric minor head trauma: do cranial CT scans change the therapeutic approach?

    PubMed Central

    Andrade, Felipe P; Montoro, Roberto; Oliveira, Renan; Loures, Gabriela; Flessak, Luana; Gross, Roberta; Donnabella, Camille; Puchnick, Andrea; Suzuki, Lisa; Regacini, Rodrigo

    2016-01-01

    OBJECTIVES: 1) To verify clinical signs correlated with appropriate cranial computed tomography scan indications and changes in the therapeutic approach in pediatric minor head trauma scenarios. 2) To estimate the radiation exposure of computed tomography scans with low dose protocols in the context of trauma and the additional associated risk. METHODS: Investigators reviewed the medical records of all children with minor head trauma, which was defined as a Glasgow coma scale ≥13 at the time of admission to the emergency room, who underwent computed tomography scans during the years of 2013 and 2014. A change in the therapeutic approach was defined as a neurosurgical intervention performed within 30 days, hospitalization, >12 hours of observation, or neuro-specialist evaluation. RESULTS: Of the 1006 children evaluated, 101 showed some abnormality on head computed tomography scans, including 49 who were hospitalized, 16 who remained under observation and 36 who were dismissed. No patient underwent neurosurgery. No statistically significant relationship was observed between patient age, time between trauma and admission, or signs/symptoms related to trauma and abnormal imaging results. A statistically significant relationship between abnormal image results and a fall higher than 1.0 meter was observed (p=0.044). The mean effective dose was 2.0 mSv (0.1 to 6.8 mSv), corresponding to an estimated additional cancer risk of 0.05%. CONCLUSION: A computed tomography scan after minor head injury in pediatric patients did not show clinically relevant abnormalities that could lead to neurosurgical indications. Patients who fell more than 1.0 m were more likely to have changes in imaging tests, although these changes did not require neurosurgical intervention; therefore, the use of computed tomography scans may be questioned in this group. The results support the trend of more careful indications for cranial computed tomography scans for children with minor head trauma. PMID

  19. Limited value of CT brain scans in the staging of small cell lung cancer

    SciTech Connect

    Johnson, D.H.; Windham, W.W.; Allen, J.H.; Greco, F.A.

    1983-01-01

    Computed tomography of the brain was performed as part of the initial staging evaluation of 84 patients with small cell lung cancer. Brain scans indicative of metastatic disease were obtained in 12 (14%) patients, two of whom had no neurologic signs or symptoms. One of these had no other extrathoracic disease. Brainscans without evidence of metastatic disease were obtained in 72 patients, 58 (80.5%) of whom had no signs or symptoms suggestive of metastatic intracranial disease. In the 14 patients with neurologic symptoms but negative computed tomographic scans, other explanations than brain metastases were found. It was concluded that head scanning is a sensitive and accurate method of detecting central nervous system metastases in patients with small cell lung cancer. However, head computed tomography should not be included as part of the initial staging evaluation of the neurologically asymptomatic patients. In only one of 60 such patients did the brain scan change the initial clinical staging, which included chest films, liver and bone scans, and bone marrow biopsy.

  20. CT -- Body

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses special x-ray ... Body? What is CT Scanning of the Body? Computed tomography, more commonly known as a CT or CAT ...

  1. AB021. Validation of real-world, non-research thoracic CT scans for quantitative analysis of COPD

    PubMed Central

    Dandurand, Ronald J.; Dandurand, Myriam; San José Estépar, Raúl; Bourbeau, Jean; Eidelman, David H.

    2016-01-01

    Background Quantitative CT (QCT) imaging plays an important role in phenotyping COPD and uses the voxel density histogram to measure total lung volume (TLV) and emphysema surrogates: low attenuation area (LAA) and lung density (LD). LD is often volume corrected using the predicted total lung capacity (TLC) to compensate for submaximal inspiration prior to image acquisition. QCT is carried out with careful attention to quality control including scanner make/model, calibration frequency, lung volume, acquisition protocol, and the use of contrast, and bears a financial and radiation cost. We wished to determine if: (I) thoracic CT scans acquired for clinical indications on a variety of scanners from different centres with varying calibration frequency, acquisition protocols and only simple breath holding instructions could yield reproducible data; (II) volume correcting LAA and LD using the pulmonary function test (PFT) measured TLC would compensate for submaximal inspiration better than using the predicted TLC; and (III) contrast infusion causes predictable changes in the QCT metrics TLV, LAA and LD. Methods A total of 82 subjects (67 COPD, 15 non-COPD) from a community respirology practice had at least 2 CT scans judged free of significant infiltrates, performed on 10 different models of scanner in 7 different community hospitals or radiology centres for clinical indications within a 13-month period and had pulmonary function tests performed respecting ATS criteria within 14 months of at least 1 CT scan. Images were analysed with Airway Inspector in ITALIC FONT (airwayinspector.acil-bwh.org) for LAA [<-950 Hounsfield Unit (HU)], LD (at 15th percentile + 1,000 HU) and TLV. 46 paired non-contrast scans (NC/NC) and 42 paired contrast/non-contrast scans (C/NC, 23 CT angio with early infusion, 19 routine contrast with late infusion) were used to construct identity plots for TLV, LAA, LD, and LAA and LD corrected for both predicted TLC and PFT measured TLC. LAA was volume

  2. Apoptosis inducing capacity of Holothuria arenicola in CT26 colon carcinoma cells in vitro and in vivo

    PubMed Central

    Baharara, Javad; Amini, Elaheh; Afzali, Mahbubeh; Nikdel, Najme; Mostafapour, Asma; Kerachian, Mohammad Amin

    2016-01-01

    Objective(s): Sea cucumber is one of the classes of echinoderms, which is considered as a health marine product and possess various biological characteristics with therapeutic application. The present investigation attempted to evaluate the potential of anti-cancer Persian Gulf sea cucumber species Holothuria arenicola (H. arenicola) aqueous extract on mice colon carcinoma cells in vitro and in vivo. Materials and Methods: The CT26 carcinoma cells were treated with various concentrations of extract in 24 and 48 hr, and then its anti-proliferative effect was measured by MTT assay and morphological observations. The apoptotic effect was examined by fluorescence microscopy (DNA fragmentation assay), Flow cytometry, caspase-3 and -9 colorimetric assays. The in vivo anti-tumor efficacy of sea cucumber extract on CT26 tumor cells transplanted in BALB/c mice was also investigated. Results: The results showed that the water extract of sea cucumber revealed remarkable anti-proliferative effect on CT26 tumor cells with IC50= 31 µg/ml with recruitment of intrinsic apoptotic pathway in vitro. In addition, the colon tumor volume in treated groups remarkably reduced in homozygous mice. Histopathological examination elucidated that sea cucumber extract attenuated tumor size and volume along with apoptosis characteristics. Moreover, RT-PCR analysis revealed that sea cucumber extract induced intrinsic apoptosis in vivo through suppression of Bcl-2 expression. Conclusion: Our data confirmed this notion that sea cucumber administrates anti-cancer effect that can be used as complementary in preclinical experiments, so further characterization are recommended for detection sea cucumber metabolites and clinical application. PMID:27279978

  3. Data-fusion display system with volume rendering of intraoperatively scanned CT images.

    PubMed

    Hayashibe, Mitsuhiro; Suzuki, Naoki; Hattori, Asaki; Otake, Yoshito; Suzuki, Shigeyuki; Nakata, Norio

    2005-01-01

    In this study we have designed and created a data-fusion display that has enabled volumetric MIP image navigation using intraoperative C-arm CT data in the operating room. The 3D volumetric data reflecting a patient's inner structure is directly displayed on the monitor through video images of the surgical field using a 3D optical tracking system, a ceiling-mounted articulating monitor, and a small size video camera mounted at the back of the monitor. The system performance was validated in an experiment carried out in the operating room.

  4. Template-based automatic extraction of the joint space of foot bones from CT scan

    NASA Astrophysics Data System (ADS)

    Park, Eunbi; Kim, Taeho; Park, Jinah

    2016-03-01

    Clean bone segmentation is critical in studying the joint anatomy for measuring the spacing between the bones. However, separation of the coupled bones in CT images is sometimes difficult due to ambiguous gray values coming from the noise and the heterogeneity of bone materials as well as narrowing of the joint space. For fine reconstruction of the individual local boundaries, manual operation is a common practice where the segmentation remains to be a bottleneck. In this paper, we present an automatic method for extracting the joint space by applying graph cut on Markov random field model to the region of interest (ROI) which is identified by a template of 3D bone structures. The template includes encoded articular surface which identifies the tight region of the high-intensity bone boundaries together with the fuzzy joint area of interest. The localized shape information from the template model within the ROI effectively separates the bones nearby. By narrowing the ROI down to the region including two types of tissue, the object extraction problem was reduced to binary segmentation and solved via graph cut. Based on the shape of a joint space marked by the template, the hard constraint was set by the initial seeds which were automatically generated from thresholding and morphological operations. The performance and the robustness of the proposed method are evaluated on 12 volumes of ankle CT data, where each volume includes a set of 4 tarsal bones (calcaneus, talus, navicular and cuboid).

  5. A decision support scheme for vertebral geometry on body CT scans

    NASA Astrophysics Data System (ADS)

    Hayashi, Tatsuro; Chen, Huayue; Miyamoto, Kei; Zhou, Xiangrong; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2011-03-01

    For gaining a better understanding of bone quality, a great deal of attention has been paid to vertebral geometry in anatomy. The aim of this study was to design a decision support scheme for vertebral geometries. The proposed scheme consists of four parts: (1) automated extraction of bone, (2) generation of median plane image of spine, (3) detection of vertebrae, (4) quantification of vertebral body width, depth, cross-sectional area (CSA), and trabecular bone mineral density (BMD). The proposed scheme was applied to 10 CT cases and compared with manual tracking performed by an anatomy expert. Mean differences in the width, depth, CSA, and trabecular BMD were 3.1 mm, 1.4 mm, 88.7 mm2, and 7.3 mg/cm3, respectively. We found moderate or high correlations in vertebral geometry between our scheme and manual tracking (r > 0.72). In contrast, measurements obtained by using our scheme were slightly smaller than those acquired from manual tracking. However, the outputs of the proposed scheme in most CT cases were regarded to be appropriate on the basis of the subjective assessment of an anatomy expert. Therefore, if the appropriate outputs from the proposed scheme are selected in advance by an anatomy expert, the results can potentially be used for an analysis of vertebral body geometries.

  6. A Multiatlas Segmentation Using Graph Cuts with Applications to Liver Segmentation in CT Scans

    PubMed Central

    2014-01-01

    An atlas-based segmentation approach is presented that combines low-level operations, an affine probabilistic atlas, and a multiatlas-based segmentation. The proposed combination provides highly accurate segmentation due to registrations and atlas selections based on the regions of interest (ROIs) and coarse segmentations. Our approach shares the following common elements between the probabilistic atlas and multiatlas segmentation: (a) the spatial normalisation and (b) the segmentation method, which is based on minimising a discrete energy function using graph cuts. The method is evaluated for the segmentation of the liver in computed tomography (CT) images. Low-level operations define a ROI around the liver from an abdominal CT. We generate a probabilistic atlas using an affine registration based on geometry moments from manually labelled data. Next, a coarse segmentation of the liver is obtained from the probabilistic atlas with low computational effort. Then, a multiatlas segmentation approach improves the accuracy of the segmentation. Both the atlas selections and the nonrigid registrations of the multiatlas approach use a binary mask defined by coarse segmentation. We experimentally demonstrate that this approach performs better than atlas selections and nonrigid registrations in the entire ROI. The segmentation results are comparable to those obtained by human experts and to other recently published results. PMID:25276219

  7. The application of metal artifact reduction (MAR) in CT scans for radiation oncology by monoenergetic extrapolation with a DECT scanner.

    PubMed

    Schwahofer, Andrea; Bär, Esther; Kuchenbecker, Stefan; Grossmann, J Günter; Kachelrieß, Marc; Sterzing, Florian

    2015-12-01

    Metal artifacts in computed tomography CT images are one of the main problems in radiation oncology as they introduce uncertainties to target and organ at risk delineation as well as dose calculation. This study is devoted to metal artifact reduction (MAR) based on the monoenergetic extrapolation of a dual energy CT (DECT) dataset. In a phantom study the CT artifacts caused by metals with different densities: aluminum (ρ Al=2.7 g/cm(3)), titanium (ρ Ti=4.5 g/cm(3)), steel (ρ steel=7.9 g/cm(3)) and tungsten (ρ W=19.3g/cm(3)) have been investigated. Data were collected using a clinical dual source dual energy CT (DECT) scanner (Siemens Sector Healthcare, Forchheim, Germany) with tube voltages of 100 kV and 140 kV(Sn). For each tube voltage the data set in a given volume was reconstructed. Based on these two data sets a voxel by voxel linear combination was performed to obtain the monoenergetic data sets. The results were evaluated regarding the optical properties of the images as well as the CT values (HU) and the dosimetric consequences in computed treatment plans. A data set without metal substitute served as the reference. Also, a head and neck patient with dental fillings (amalgam ρ=10 g/cm(3)) was scanned with a single energy CT (SECT) protocol and a DECT protocol. The monoenergetic extrapolation was performed as described above and evaluated in the same way. Visual assessment of all data shows minor reductions of artifacts in the images with aluminum and titanium at a monoenergy of 105 keV. As expected, the higher the densities the more distinctive are the artifacts. For metals with higher densities such as steel or tungsten, no artifact reduction has been achieved. Likewise in the CT values, no improvement by use of the monoenergetic extrapolation can be detected. The dose was evaluated at a point 7 cm behind the isocenter of a static field. Small improvements (around 1%) can be seen with 105 keV. However, the dose uncertainty remains of the order of 10

  8. The application of metal artifact reduction (MAR) in CT scans for radiation oncology by monoenergetic extrapolation with a DECT scanner.

    PubMed

    Schwahofer, Andrea; Bär, Esther; Kuchenbecker, Stefan; Grossmann, J Günter; Kachelrieß, Marc; Sterzing, Florian

    2015-12-01

    Metal artifacts in computed tomography CT images are one of the main problems in radiation oncology as they introduce uncertainties to target and organ at risk delineation as well as dose calculation. This study is devoted to metal artifact reduction (MAR) based on the monoenergetic extrapolation of a dual energy CT (DECT) dataset. In a phantom study the CT artifacts caused by metals with different densities: aluminum (ρ Al=2.7 g/cm(3)), titanium (ρ Ti=4.5 g/cm(3)), steel (ρ steel=7.9 g/cm(3)) and tungsten (ρ W=19.3g/cm(3)) have been investigated. Data were collected using a clinical dual source dual energy CT (DECT) scanner (Siemens Sector Healthcare, Forchheim, Germany) with tube voltages of 100 kV and 140 kV(Sn). For each tube voltage the data set in a given volume was reconstructed. Based on these two data sets a voxel by voxel linear combination was performed to obtain the monoenergetic data sets. The results were evaluated regarding the optical properties of the images as well as the CT values (HU) and the dosimetric consequences in computed treatment plans. A data set without metal substitute served as the reference. Also, a head and neck patient with dental fillings (amalgam ρ=10 g/cm(3)) was scanned with a single energy CT (SECT) protocol and a DECT protocol. The monoenergetic extrapolation was performed as described above and evaluated in the same way. Visual assessment of all data shows minor reductions of artifacts in the images with aluminum and titanium at a monoenergy of 105 keV. As expected, the higher the densities the more distinctive are the artifacts. For metals with higher densities such as steel or tungsten, no artifact reduction has been achieved. Likewise in the CT values, no improvement by use of the monoenergetic extrapolation can be detected. The dose was evaluated at a point 7 cm behind the isocenter of a static field. Small improvements (around 1%) can be seen with 105 keV. However, the dose uncertainty remains of the order of 10

  9. [CT scans in children with head/brain injury: five years after the revision of the guideline on "mild traumatic head/brain injury"].

    PubMed

    Hageman, G Gerard

    2015-01-01

    In 2010 the guideline on mild traumatic head/ brain injury for both adults and children was revised under the supervision of the Dutch Neurology Society. The revised guideline endorsed rules for decisions on whether to carry out diagnostic imaging investigations (brain CT scanning) and formulates indications for admission. Unfortunately, 5 years after its introduction, it is clear that the guideline rules result in excessive brain CT scanning, in which no more serious head injury is diagnosed. Brain injury may be present in (small) children even if symptoms are absent at first presentation. Also, clinical signs do not predict intracranial complications. This was nicely demonstrated in a study by Tilma, Bekhof and Brand of 410 children with mTBI: no clinical symptom or sign reliably predicted the risk of intracranial bleeding. They advise hospitalisation for observation instead of brain CT scanning. It may be necessary to review part of the Dutch guideline on mTBI. PMID:25690074

  10. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    NASA Astrophysics Data System (ADS)

    Mendrik, Adriënne M.; Vonken, Evert-jan; van Ginneken, Bram; de Jong, Hugo W.; Riordan, Alan; van Seeters, Tom; Smit, Ewoud J.; Viergever, Max A.; Prokop, Mathias

    2011-07-01

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray radiation that can be used per sequential scan is limited, which results in a high level of noise. To detect areas of abnormal perfusion, perfusion parameters are derived from the CTP data, such as the cerebral blood flow (CBF). Algorithms to determine perfusion parameters, especially singular value decomposition, are very sensitive to noise. Therefore, noise reduction is an important preprocessing step for CTP analysis. In this paper, we propose a time-intensity profile similarity (TIPS) bilateral filter to reduce noise in 4D CTP scans, while preserving the time-intensity profiles (fourth dimension) that are essential for determining the perfusion parameters. The proposed TIPS bilateral filter is compared to standard Gaussian filtering, and 4D and 3D (applied separately to each sequential scan) bilateral filtering on both phantom and patient data. Results on the phantom data show that the TIPS bilateral filter is best able to approach the ground truth (noise-free phantom), compared to the other filtering methods (lowest root mean square error). An observer study is performed using CBF maps derived from fifteen CTP scans of acute stroke patients filtered with standard Gaussian, 3D, 4D and TIPS bilateral filtering. These CBF maps were blindly presented to two observers that indicated which map they preferred for (1) gray/white matter differentiation, (2) detectability of infarcted area and (3) overall image quality. Based on these results, the TIPS bilateral filter ranked best and its CBF maps were scored to have the best overall image quality in 100% of the cases by both observers. Furthermore, quantitative CBF and cerebral blood volume values in both the phantom and the

  11. Bone scanning in patients with early breast carcinoma: should it be a routine staging procedure

    SciTech Connect

    Lee, Y.T.

    1981-02-01

    Bone scanning is a sensitive test for the detection of metastatic breast cancer, but not all abnormal findings on bone scan are diagnostic of skeletal metastasis. Recent studies have found a relatively low rate (less than or equal to 5%) of abnormal scans in patients with Stage I and II breast cancers, and only half of those with positive scans subsequently had documented bony metastasis. The overwhelming clinical experiences summarized here question the value of including bone scanning as part of the routine work-up of patients with early breast cancers.

  12. Flexydos3D: A new deformable anthropomorphic 3D dosimeter readout with optical CT scanning

    NASA Astrophysics Data System (ADS)

    De Deene, Yves; Hill, Robin; Skyt, Peter S.; Booth, Jeremy

    2015-01-01

    A new deformable polydimethylsiloxane (PDMS) based dosimeter is proposed that can be cast in an anthropomorphic shape and that can be used for 3D radiation dosimetry of deformable targets. The new material has additional favorable characteristics as it is tissue equivalent for high-energy photons, easy to make and is non-toxic. In combination with dual wavelength optical scanning, it is a powerful dosimeter for dose verification of image gated or organ tracked radiotherapy with moving and deforming targets.

  13. Registration of prone and supine CT colonography scans using correlation optimized warping and canonical correlation analysis

    SciTech Connect

    Wang Shijun; Yao Jianhua; Liu Jiamin; Petrick, Nicholas; Van Uitert, Robert L.; Periaswamy, Senthil; Summers, Ronald M.

    2009-12-15

    Purpose: In computed tomographic colonography (CTC), a patient will be scanned twice--Once supine and once prone--to improve the sensitivity for polyp detection. To assist radiologists in CTC reading, in this paper we propose an automated method for colon registration from supine and prone CTC scans. Methods: We propose a new colon centerline registration method for prone and supine CTC scans using correlation optimized warping (COW) and canonical correlation analysis (CCA) based on the anatomical structure of the colon. Four anatomical salient points on the colon are first automatically distinguished. Then correlation optimized warping is applied to the segments defined by the anatomical landmarks to improve the global registration based on local correlation of segments. The COW method was modified by embedding canonical correlation analysis to allow multiple features along the colon centerline to be used in our implementation. Results: We tested the COW algorithm on a CTC data set of 39 patients with 39 polyps (19 training and 20 test cases) to verify the effectiveness of the proposed COW registration method. Experimental results on the test set show that the COW method significantly reduces the average estimation error in a polyp location between supine and prone scans by 67.6%, from 46.27{+-}52.97 to 14.98 mm{+-}11.41 mm, compared to the normalized distance along the colon centerline algorithm (p<0.01). Conclusions: The proposed COW algorithm is more accurate for the colon centerline registration compared to the normalized distance along the colon centerline method and the dynamic time warping method. Comparison results showed that the feature combination of z-coordinate and curvature achieved lowest registration error compared to the other feature combinations used by COW. The proposed method is tolerant to centerline errors because anatomical landmarks help prevent the propagation of errors across the entire colon centerline.

  14. Visible changes in lesion borders on CT scan after five years poststroke, and long-term recovery in aphasia.

    PubMed

    Naeser, M A; Palumbo, C L; Prete, M N; Fitzpatrick, P M; Mimura, M; Samaraweera, R; Albert, M L

    1998-03-01

    This study examined 12 aphasia patients at approximately 1 year poststroke (Time 1) and again at 5-12 years poststroke (Time 2) with language testing and CT scan. Significant increases in naming scores, and phrase length in nonfluent speech were observed after 5 years poststroke. Significant expansion in visible lesion borders (lesion size) was observed after 5 years poststroke; an increase in lesion size of > 1% was present in 9/12 cases (75%). Not one case had a second stroke. Thus, it appears that even though lesion expansion may occur after 5 years poststroke, as long as this expansion is unilateral and gradual, it has no adverse effect on language, and in fact, continued recovery in naming and nonfluent speech may also occur. Long-term recovery patterns in aphasia which may be associated with brain reorganization deserve further study, especially with functional brain imaging techniques.

  15. Kinematic constituents of the extreme head turn of Strix aluco estimated by means of CT-scanning.

    PubMed

    Grytsyshina, E E; Kuznetsov, A N; Panyutina, A A

    2016-01-01

    To analyze extreme sideways turn of the head in owls, a total fresh specimen of Strix aluco was frozen in respective posture and CT-scanned. The maximum turn to one side was found to be 360°, provided that the head is drawn into the shoulders. 160° of this full turn are ensured by the neck axial rotation (this includes ~90° twist of the head relative to epistropheus and, posterior to it, less than 15° per every cervical joint), and the rest 200° are ensured by combination of dorsal and lateral flexion. The 15° limit is overcome in five joints in respect of dorsiflexion, and in six joints in respect of lateral flexion. So large a degree of lateral mobility is unusual among birds, and is appreciated as a crucial adaptation to extreme head turning. PMID:27021365

  16. Solitary pulmonary amyloidoma mimicking lung cancer on 18F-FDG PET-CT scan in systemic lupus erythematosus patient.

    PubMed

    Barešić, M; Sreter, K B; Brčić, L; Hećimović, A; Janevski, Z; Anić, B

    2015-12-01

    Localized amyloid deposits (tumoral amyloidosis or amyloidoma) are uncommon form of amyloidosis and nodular pulmonary amyloidomas are rarely found. This incidental finding can mimic a bronchopulmonary neoplasm and may occur secondarily to an infectious, inflammatory or lymphoproliferative disease. We report a case of a 62-year-old female with long-standing systemic lupus erythematosus (SLE) with low compliance who presented with radiologically-verified solitary pulmonary nodule. Work-up included positron emission tomography-computed tomography (PET-CT) scan, which revealed hypermetabolic uptake of (18)F-fluorodeoxyglucose, and lobectomy was performed. Staining of the tissue was positive for Congo red and was green birefringent under polarized light. Immunohistochemical methods excluded lymphoproliferative disease and confirmed amyloidoma. SLE was controlled with antimalarials and glucocorticoids. Pulmonary amyloidoma should be considered in the differential diagnosis of solitary lung nodules.

  17. The prevalence of chondrocalcinosis of the symphysis pubis on CT scan and correlation with calcium pyrophosphate dihydrate crystal deposition disease.

    PubMed

    Patel, Trusha; Ryan, Lawrence; Dubois, Melissa; Carrera, Guillermo; Baynes, Keith; Mannem, Rajeev; Mulkerin, Jennifer; Visotcky, Alexis

    2016-03-01

    Calcium pyrophosphate dihydrate (CPP) crystal deposition in the articular cartilage can often be seen radiographically as chondrocalcinosis (CC). CPP crystals preferentially deposit in fibrocartilages such as the knee menisci and symphysis pubis (SP). We sought to determine the prevalence of CC in the SP on computed tomography (CT) of the abdomen and pelvis. This retrospective study involved readings on 1070 consecutive CTs of the abdomen and pelvis performed over 3 months in patients over 65 years of age. Medical records of 226 patients found to have CC were reviewed to determine age, gender, documentation of CPPD on problem lists or in medical histories, and whether radiology readings of the CTs mentioned CC. SP CC was identified in 21.1 % (226/1070) of consecutive CT scans with the mean age of CT+ patients being 78.6. Of the 226 patients with SP CC, the observation of CC was documented in only 5.3 % (12/226) of the radiology reports. Of the 12 instances in which the radiology reports mentioned CC, this observation was never (0/12) transmitted to the medical history or problem list. The prevalence of SP CC in patients older than 65 was 21.1 %. Since the majority of CTs of the abdomen and pelvis are not ordered for evaluation of musculoskeletal conditions, this is likely a true prevalence without selection bias. When CC of the SP was present on images, radiologists routinely overlooked or chose not to report CC. Even in the rare instances when it was reported, that information was not added to the medical history or problem list. There are several clinical situations (e.g., acute monoarthritis or atypical osteoarthritis) in which recognizing that a patient has CPP deposition would be useful. Taking the time to review images may yield clinically important findings that are not mentioned anywhere on the patient chart.

  18. Anatomy-based registration of CT-scan and intraoperative X-ray images for guiding a surgical robot.

    PubMed

    Guéziec, A; Kazanzides, P; Williamson, B; Taylor, R H

    1998-10-01

    We describe new methods for rigid registration of a preoperative computed tomography (CT)-scan image to a set of intraoperative X-ray fluoroscopic images, for guiding a surgical robot to its trajectory planned from CT. Our goal is to perform the registration, i.e., compute a rotation and translation of one data set with respect to the other to within a prescribed accuracy, based upon bony anatomy only, without external fiducial markers. With respect to previous approaches, the following aspects are new: 1) we correct the geometric distortion in fluoroscopic images and calibrate them directly with respect to the robot by affixing to it a new calibration device designed as a radiolucent rod with embedded metallic markers, and by moving the device along two planes, while radiographs are being acquired at regular intervals; 2) the registration uses an algorithm for computing the best transformation between a set of lines in three space, the (intraoperative) X-ray paths, and a set of points on the surface of the bone (imaged preoperatively), in a statistically robust fashion, using the Cayley parameterization of a rotation; and 3) to find corresponding sets of points to the X-ray paths on the surfaces, our new approach consists of extracting the surface apparent contours for a given viewpoint, as a set of closed three-dimensional nonplanar curves, before registering the apparent contours to X-ray paths. Aside from algorithms, there are a number of major technical difficulties associated with engineering a clinically viable system using anatomy and image-based registration. To detect and solve them, we have so far conducted two experiments with the surgical robot in an operating room (OR), using CT and fluoroscopic image data of a cadaver bone, and attempting to faithfully simulate clinical conditions. Such experiments indicate that intraoperative X-ray-based registration is a promising alternative to marker-based registration for clinical use with our proposed method.

  19. Recurrent surgical site infection of the spine diagnosed by dual (18)F-NaF-bone PET/CT with early-phase scan.

    PubMed

    Shim, Jai-Joon; Lee, Jeong Won; Jeon, Min Hyok; Lee, Sang Mi

    2016-09-01

    We report a case of a 31-year-old man who showed recurrently elevated level of the serum inflammatory marker C-reactive protein (CRP) after spinal operation. He underwent (18)F-flurodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) and dual (18)F-sodium-fluoride ((18)F-NaF) PET/CT with an additional early-phase scan to find a hidden inflammation focus. Only mildly increased (18)F-FDG was found at the surgical site of T11 spine on (18)F-FDG PET/CT. In contrast, dual (18)F-NaF bone PET/CT with early-phase scan demonstrated focal active inflammation at the surgical site of T11 spine. After a revision operation of the T11 spine, serum CRP level decreased to the normal range without any symptom or sign of inflammation. Inflammatory focus in the surgical site of the spine can be detected with using dual (18)F-NaF bone PET/CT scan with early-phase scan.

  20. Fuzzy Clustering Applied to ROI Detection in Helical Thoracic CT Scans with a New Proposal and Variants.

    PubMed

    Castro, Alfonso; Rey, Alberto; Boveda, Carmen; Arcay, Bernardino; Sanjurjo, Pedro

    2016-01-01

    The detection of pulmonary nodules is one of the most studied problems in the field of medical image analysis due to the great difficulty in the early detection of such nodules and their social impact. The traditional approach involves the development of a multistage CAD system capable of informing the radiologist of the presence or absence of nodules. One stage in such systems is the detection of ROI (regions of interest) that may be nodules in order to reduce the space of the problem. This paper evaluates fuzzy clustering algorithms that employ different classification strategies to achieve this goal. After characterising these algorithms, the authors propose a new algorithm and different variations to improve the results obtained initially. Finally it is shown as the most recent developments in fuzzy clustering are able to detect regions that may be nodules in CT studies. The algorithms were evaluated using helical thoracic CT scans obtained from the database of the LIDC (Lung Image Database Consortium). PMID:27517049

  1. CIDI-lung-seg: a single-click annotation tool for automatic delineation of lungs from CT scans.

    PubMed

    Mansoor, Awais; Bagci, Ulas; Foster, Brent; Xu, Ziyue; Douglas, Deborah; Solomon, Jeffrey M; Udupa, Jayaram K; Mollura, Daniel J

    2014-01-01

    Accurate and fast extraction of lung volumes from computed tomography (CT) scans remains in a great demand in the clinical environment because the available methods fail to provide a generic solution due to wide anatomical variations of lungs and existence of pathologies. Manual annotation, current gold standard, is time consuming and often subject to human bias. On the other hand, current state-of-the-art fully automated lung segmentation methods fail to make their way into the clinical practice due to their inability to efficiently incorporate human input for handling misclassifications and praxis. This paper presents a lung annotation tool for CT images that is interactive, efficient, and robust. The proposed annotation tool produces an "as accurate as possible" initial annotation based on the fuzzy-connectedness image segmentation, followed by efficient manual fixation of the initial extraction if deemed necessary by the practitioner. To provide maximum flexibility to the users, our annotation tool is supported in three major operating systems (Windows, Linux, and the Mac OS X). The quantitative results comparing our free software with commercially available lung segmentation tools show higher degree of consistency and precision of our software with a considerable potential to enhance the performance of routine clinical tasks. PMID:25570151

  2. Fuzzy Clustering Applied to ROI Detection in Helical Thoracic CT Scans with a New Proposal and Variants

    PubMed Central

    Castro, Alfonso; Boveda, Carmen; Arcay, Bernardino; Sanjurjo, Pedro

    2016-01-01

    The detection of pulmonary nodules is one of the most studied problems in the field of medical image analysis due to the great difficulty in the early detection of such nodules and their social impact. The traditional approach involves the development of a multistage CAD system capable of informing the radiologist of the presence or absence of nodules. One stage in such systems is the detection of ROI (regions of interest) that may be nodules in order to reduce the space of the problem. This paper evaluates fuzzy clustering algorithms that employ different classification strategies to achieve this goal. After characterising these algorithms, the authors propose a new algorithm and different variations to improve the results obtained initially. Finally it is shown as the most recent developments in fuzzy clustering are able to detect regions that may be nodules in CT studies. The algorithms were evaluated using helical thoracic CT scans obtained from the database of the LIDC (Lung Image Database Consortium). PMID:27517049

  3. Comparisons of Derived Metrics from Computed Tomography (CT) Scanned Images of Fluvial Sediment from Gravel-Bed Flume Experiments

    NASA Astrophysics Data System (ADS)

    Voepel, Hal; Ahmed, Sharif; Hodge, Rebecca; Leyland, Julian; Sear, David

    2016-04-01

    Uncertainty in bedload estimates for gravel bed rivers is largely driven by our inability to characterize arrangement, orientation and resultant forces of fluvial sediment in river beds. Water working of grains leads to structural differences between areas of the bed through particle sorting, packing, imbrication, mortaring and degree of bed armoring. In this study, non-destructive, micro-focus X-ray computed tomography (CT) imaging in 3D is used to visualize, quantify and assess the internal geometry of sections of a flume bed that have been extracted keeping their fabric intact. Flume experiments were conducted at 1:1 scaling of our prototype river. From the volume, center of mass, points of contact, and protrusion of individual grains derived from 3D scan data we estimate 3D static force properties at the grain-scale such as pivoting angles, buoyancy and gravity forces, and local grain exposure. Here metrics are derived for images from two flume experiments: one with a bed of coarse grains (>4mm) and the other where sand and clay were incorporated into the coarse flume bed. In addition to deriving force networks, comparison of metrics such as critical shear stress, pivot angles, grain distributions, principle axis orientation, and pore space over depth are made. This is the first time bed stability has been studied in 3D using CT scanned images of sediment from the bed surface to depths well into the subsurface. The derived metrics, inter-granular relationships and characterization of bed structures will lead to improved bedload estimates with reduced uncertainty, as well as improved understanding of relationships between sediment structure, grain size distribution and channel topography.

  4. Benefit of cerebrospinal fluid spectrophotometry in the assessment of CT scan negative suspected subarachnoid haemorrhage: a diagnostic accuracy study.

    PubMed

    Hann, Angus; Chu, Kevin; Greenslade, Jaimi; Williams, Julian; Brown, Anthony

    2015-01-01

    This study aimed to determine if performing cerebrospinal fluid spectrophotometry in addition to visual inspection detects more ruptured cerebral aneurysms than performing cerebrospinal fluid visual inspection alone in patients with a normal head CT scan but suspected of suffering an aneurysmal subarachnoid haemorrhage (SAH). We performed a single-centre retrospective study of patients presenting to the emergency department of a tertiary hospital who underwent both head CT scan and lumbar puncture to exclude SAH. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of an approach utilising both spectrophotometry and visual inspection (combined approach) was compared to visual inspection alone. A total of 409 patients (mean age 37.8 years, 56.2% female) were recruited and six (1.5%) had a cerebral aneurysm on angiography. The sensitivity of visual inspection was 50% (95% confidence interval [CI]: 12.4-82.6%), specificity was 99% (95% CI: 97.5-99.7%), PPV was 42.9% (95% CI: 10.4-81.3%) and NPV was 99.2% (95% CI: 97.8-99.8%). The combined approach had a sensitivity of 100% (95% CI: 54.1-100%), specificity of 79.7% (95% CI: 75.4-83.5%), PPV of 6.8% (95% CI: 2.6-14.3%) and a NPV of 100% (95% CI: 98.8-100%). The sensitivity of the combined approach was not significantly different to that of visual inspection alone (p=0.25). Visual inspection had a significantly higher specificity than the combined approach (p<0.01). The combined approach detected more cases of aneurysmal SAH than visual inspection alone, however the difference in sensitivity was not statistically significant. Visual xanthochromia should prompt angiography because of a superior specificity and PPV. Due to its reduced sensitivity, caution should be applied when using only visual inspection of the supernatant.

  5. Neonatal Death Dwarfism in a Girl with Distinctive Bone Dysplasia Compatible with Grebe Chondrodysplasia: Analysis by CT Scan-based Phenotype

    PubMed Central

    Al Kaissi, Ali; Chehida, Farid Ben; Ganger, Rudolf; Grill, Franz

    2014-01-01

    We report on a female fetus noted to have severe malformative type of skeletal dysplasia on ultrasonography done at 35 weeks gestation. The girl died shortly after birth. Clinical examination showed a fetus with severe dwarfism, extensive long and short bones, and bone deficiencies associated with multiple dislocations. Computed tomography (CT) scan-based phenotype showed a complex constellation of malformations consistent with the diagnosis of Grebe syndrome. Parents being first cousins (consanguineous marriage) strongly suggests autosomal recessive pattern of inheritance. To our knowledge, this is the first report of neonatal death dwarfism of Grebe syndrome analyzed by CT scan-based phenotype. PMID:25337439

  6. Incidental Detection of Follicular Thyroid Carcinoma in 68Ga-PSMA PET/CT Imaging.

    PubMed

    Sager, Sait; Vatankulu, Betül; Uslu, Lebriz; Sönmezoglu, Kerim

    2016-09-01

    Prostate-specific membrane antigen (PSMA) is a type II transmembrane protein. It has been shown to be expressed in various solid malignant neoplasms. We report a case of a prostate cancer patient who underwent (68)Ga-PSMA PET/CT imaging. There is a large thyroid nodule in the right thyroid gland, which had intense PSMA accumulation. Follicular thyroid lesions can be seen on (68)Ga-PSMA PET/CT imaging. PMID:26966127

  7. Comparative study on measured variables and sensitivity to bone microstructural changes induced by weightlessness between in vivo and ex vivo micro-CT scans.

    PubMed

    Sun, Lian Wen; Wang, Chao; Pu, Fang; Li, De Yu; Niu, Hai Jun; Fan, Yu Bo

    2011-01-01

    Depending on the experimental design, micro-CT can be used to examine bones either in vivo or ex vivo (excised fresh or formalin-fixed). In this study we investigated if differences exist in the variables measured by micro-CT between in vivo and ex vivo scans and which kind of scan is more sensitive to the changes of bone microstructure induced by simulated weightlessness. Rat tail suspension was used to simulate the weightless condition. The same bone from either normal or tail-suspended rats was scanned by micro-CT both in vivo and ex vivo (fresh and fixed by formalin). Then, bone mineral density (BMD) and microstructural characteristics were analyzed. The results showed that no significant differences existed in the microstructural parameters of trabecular bone among in vivo, fresh, and formalin-fixed bone scans from both femurs and tibias, although BMD exhibited differences. On the other hand, most parameters of the tail-suspended rats measured by micro-CT deteriorated compared with controls. Ex vivo scanning appeared to be more sensitive to bone microstructural changes induced by tail suspension than in vivo scanning. In general, the results indicate that values obtained in vivo and ex vivo (fresh and fixed) are comparable, thus allowing for meaningful comparison of experimental results from different studies irrespective of the type of scans. In addition, this study suggests that it is better to use ex vivo scanning when evaluating bone microstructure under weightlessness. However, researchers can select any type of scan depending upon the objective and the demands of the experiment.

  8. Low electric field enhanced chemotherapy can cure mice with CT-26 colon carcinoma and induce anti-tumour immunity

    PubMed Central

    PLOTNIKOV, A; FISHMAN, D; TICHLER, T; KORENSTEIN, R; KEISARI, Y

    2004-01-01

    Low electric field cancer treatment − enhanced chemotherapy (LEFCT-EC) is a new anticancer treatment which utilizes a combination of chemotherapeutic agents and a low electric field. We investigated the antitumour effectiveness of this technique in a model of murine colon carcinoma (CT-26). The low electric field was applied to ∼65 mm3 intracutaneous tumours after intratumoral injection of 5FU, bleomycin or BCNU. We observed significant tumour size reduction and a prolongation of survival time. The complete cure of a significant fraction of animals treated by LEFCT-EC with 5FU (33%), bleomycin (51%) or BCNU (83%) was observed. Mice cured by LEFCT-EC developed resistance to a tumour challenge and their splenocytes had antitumour activity in vivo. Our results suggest that LEFCT-EC is an effective method for treatment of solid tumours. PMID:15544616

  9. Low electric field enhanced chemotherapy can cure mice with CT-26 colon carcinoma and induce anti-tumour immunity.

    PubMed

    Plotnikov, A; Fishman, D; Tichler, T; Korenstein, R; Keisari, Y

    2004-12-01

    Low electric field cancer treatment-enhanced chemotherapy (LEFCT-EC) is a new anticancer treatment which utilizes a combination of chemotherapeutic agents and a low electric field. We investigated the antitumour effectiveness of this technique in a model of murine colon carcinoma (CT-26). The low electric field was applied to approximately 65 mm3 intracutaneous tumours after intratumoral injection of 5FU, bleomycin or BCNU. We observed significant tumour size reduction and a prolongation of survival time. The complete cure of a significant fraction of animals treated by LEFCT-EC with 5FU (33%), bleomycin (51%) or BCNU (83%) was observed. Mice cured by LEFCT-EC developed resistance to a tumour challenge and their splenocytes had antitumour activity in vivo. Our results suggest that LEFCT-EC is an effective method for treatment of solid tumours.

  10. Consecutive Short-Scan CT for Geological Structure Analog Models with Large Size on In-Situ Stage.

    PubMed

    Yang, Min; Zhang, Wen; Wu, Xiaojun; Wei, Dongtao; Zhao, Yixin; Zhao, Gang; Han, Xu; Zhang, Shunli

    2016-01-01

    For the analysis of interior geometry and property changes of a large-sized analog model during a loading or other medium (water or oil) injection process with a non-destructive way, a consecutive X-ray computed tomography (XCT) short-scan method is developed to realize an in-situ tomography imaging. With this method, the X-ray tube and detector rotate 270° around the center of the guide rail synchronously by switching positive and negative directions alternately on the way of translation until all the needed cross-sectional slices are obtained. Compared with traditional industrial XCTs, this method well solves the winding problems of high voltage cables and oil cooling service pipes during the course of rotation, also promotes the convenience of the installation of high voltage generator and cooling system. Furthermore, hardware costs are also significantly decreased. This kind of scanner has higher spatial resolution and penetrating ability than medical XCTs. To obtain an effective sinogram which matches rotation angles accurately, a structural similarity based method is applied to elimination of invalid projection data which do not contribute to the image reconstruction. Finally, on the basis of geometrical symmetry property of fan-beam CT scanning, a whole sinogram filling a full 360° range is produced and a standard filtered back-projection (FBP) algorithm is performed to reconstruct artifacts-free images. PMID:27537104

  11. Consecutive Short-Scan CT for Geological Structure Analog Models with Large Size on In-Situ Stage.

    PubMed

    Yang, Min; Zhang, Wen; Wu, Xiaojun; Wei, Dongtao; Zhao, Yixin; Zhao, Gang; Han, Xu; Zhang, Shunli

    2016-01-01

    For the analysis of interior geometry and property changes of a large-sized analog model during a loading or other medium (water or oil) injection process with a non-destructive way, a consecutive X-ray computed tomography (XCT) short-scan method is developed to realize an in-situ tomography imaging. With this method, the X-ray tube and detector rotate 270° around the center of the guide rail synchronously by switching positive and negative directions alternately on the way of translation until all the needed cross-sectional slices are obtained. Compared with traditional industrial XCTs, this method well solves the winding problems of high voltage cables and oil cooling service pipes during the course of rotation, also promotes the convenience of the installation of high voltage generator and cooling system. Furthermore, hardware costs are also significantly decreased. This kind of scanner has higher spatial resolution and penetrating ability than medical XCTs. To obtain an effective sinogram which matches rotation angles accurately, a structural similarity based method is applied to elimination of invalid projection data which do not contribute to the image reconstruction. Finally, on the basis of geometrical symmetry property of fan-beam CT scanning, a whole sinogram filling a full 360° range is produced and a standard filtered back-projection (FBP) algorithm is performed to reconstruct artifacts-free images.

  12. Consecutive Short-Scan CT for Geological Structure Analog Models with Large Size on In-Situ Stage

    PubMed Central

    Yang, Min; Zhang, Wen; Wu, Xiaojun; Wei, Dongtao; Zhao, Yixin; Zhao, Gang; Han, Xu; Zhang, Shunli

    2016-01-01

    For the analysis of interior geometry and property changes of a large-sized analog model during a loading or other medium (water or oil) injection process with a non-destructive way, a consecutive X-ray computed tomography (XCT) short-scan method is developed to realize an in-situ tomography imaging. With this method, the X-ray tube and detector rotate 270° around the center of the guide rail synchronously by switching positive and negative directions alternately on the way of translation until all the needed cross-sectional slices are obtained. Compared with traditional industrial XCTs, this method well solves the winding problems of high voltage cables and oil cooling service pipes during the course of rotation, also promotes the convenience of the installation of high voltage generator and cooling system. Furthermore, hardware costs are also significantly decreased. This kind of scanner has higher spatial resolution and penetrating ability than medical XCTs. To obtain an effective sinogram which matches rotation angles accurately, a structural similarity based method is applied to elimination of invalid projection data which do not contribute to the image reconstruction. Finally, on the basis of geometrical symmetry property of fan-beam CT scanning, a whole sinogram filling a full 360° range is produced and a standard filtered back-projection (FBP) algorithm is performed to reconstruct artifacts-free images. PMID:27537104

  13. Naeglaeria infection of the central nervous system, CT scan findings: a case series.

    PubMed

    Naqi, Rohana; Azeemuddin, Muhammad

    2013-03-01

    The imaging findings in four cases of a rare infection of the central nervous system caused by amoebae, Naeglaeria fowleri are presented. Naeglaeria fowleri are pathogenic free-living amoebae. They cause primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system. The computed tomography brain findings in 3 (75%) of our cases of pan amoebic meningoencephalitis showed non-specific brain oedema; 2 (66%) of these cases also had moderate hydrocephalus and among that 1 (50%) case showed an old lacunar infarction in peri-ventricular region. In the remaining 1 (25%) case the scan was normal with no evidence of oedema or abnormal lesion. Out of three cases with diffuse brain oedema, postcontrast images showed abnormal meningeal enhancement throughout the brain parenchyma in 1 (33%) case. However, no definite focal enhancing lesion was noted. In the rest of the cases, no abnormal parenchymal or meningeal enhancement was seen on post-contrast images. PMID:23914650

  14. Automatic Detection and Quantification of Tree-in-Bud (TIB) Opacities From CT Scans

    PubMed Central

    Yao, Jianhua; Wu, Albert; Caban, Jesus; Palmore, Tara N.; Suffredini, Anthony F.; Aras, Omer; Mollura, Daniel J.

    2012-01-01

    This study presents a novel computer-assisted detection (CAD) system for automatically detecting and precisely quantifying abnormal nodular branching opacities in chest computed tomography (CT), termed tree-in-bud (TIB) opacities by radiology literature. The developed CAD system in this study is based on 1) fast localization of candidate imaging patterns using local scale information of the images, and 2) Möobius invariant feature extraction method based on learned local shape and texture properties of TIB patterns. For fast localization of candidate imaging patterns, we use ball-scale filtering and, based on the observation of the pattern of interest, a suitable scale selection is used to retain only small size patterns. Once candidate abnormality patterns are identified, we extract proposed shape features from regions where at least one candidate pattern occupies. The comparative evaluation of the proposed method with commonly used CAD methods is presented with a dataset of 60 chest CTs (laboratory confirmed 39 viral bronchiolitis human parainfluenza CTs and 21 normal chest CTs). The quantitative results are presented as the area under the receiver operator characteristics curves and a computer score (volume affected by TIB) provided as an output of the CAD system. In addition, a visual grading scheme is applied to the patient data by three well-trained radiologists. Inter-observer and observer–computer agreements are obtained by the relevant statistical methods over different lung zones. Experimental results demonstrate that the proposed CAD system can achieve high detection rates with an overall accuracy of 90.96%.Moreover, correlations of observer–observer (R2 = 0.8848,p <0.01) and observer–CAD agreements (R2 = 0.824,p <0.01) validate the feasibility of the use of the proposed CAD system in detecting and quantifying TIB patterns. PMID:22434795

  15. Pore space connectivity and porosity using CT scans of tropical soils

    NASA Astrophysics Data System (ADS)

    Previatello da Silva, Livia; de Jong Van Lier, Quirijn

    2015-04-01

    Microtomography has been used in soil physics for characterization and allows non-destructive analysis with high-resolution, yielding a three-dimensional representation of pore space and fluid distribution. It also allows quantitative characterization of pore space, including pore size distribution, shape, connectivity, porosity, tortuosity, orientation, preferential pathways and is also possible predict the saturated hydraulic conductivity using Darcy's equation and a modified Poiseuille's equation. Connectivity of pore space is an important topological property of soil. Together with porosity and pore-size distribution, it governs transport of water, solutes and gases. In order to quantify and analyze pore space (quantifying connectivity of pores and porosity) of four tropical soils from Brazil with different texture and land use, undisturbed samples were collected in São Paulo State, Brazil, with PVC ring with 7.5 cm in height and diameter of 7.5 cm, depth of 10 - 30 cm from soil surface. Image acquisition was performed with a CT system Nikon XT H 225, with technical specifications of dual reflection-transmission target system including a 225 kV, 225 W high performance Xray source equipped with a reflection target with pot size of 3 μm combined with a nano-focus transmission module with a spot size of 1 μm. The images were acquired at specific energy level for each soil type, according to soil texture, and external copper filters were used in order to allow the attenuation of low frequency X-ray photons and passage of one monoenergetic beam. This step was performed aiming minimize artifacts such as beam hardening that may occur during the attenuation in the material interface with different densities within the same sample. Images were processed and analyzed using ImageJ/Fiji software. Retention curve (tension table and the pressure chamber methods), saturated hydraulic conductivity (constant head permeameter), granulometry, soil density and particle density

  16. Brain metastases detectability of routine whole body (18)F-FDG PET and low dose CT scanning in 2502 asymptomatic patients with solid extracranial tumors.

    PubMed

    Bochev, Pavel; Klisarova, Aneliya; Kaprelyan, Ara; Chaushev, Borislav; Dancheva, Zhivka

    2012-01-01

    As fluorine-18-fluorodesoxyglucose positron emission tomography/computed tomography ( (18)F-FDG PET/CT) is gaining wider availability, more and more patients with malignancies undergo whole body PET/CT, mostly to assess tumor spread in the rest of the body, but not in the brain. Brain is a common site of metastatic spread in patients with solid extracranial tumors. Gold standard in the diagnosis of brain metastases remains magnetic resonance imaging (MRI). However MRI is not routinely indicated and is not available for all cancer patients. Fluorine-18-FDG PET is considered as having poor sensitivity in detecting brain metastases, but this may not be true for PET/CT. The aim of our study was to assess the value of (18)F-FDG PET/CT in the detection of brain metastases found by whole body scan including the brain, in patients with solid extracranial neoplasms. A total of 2502 patients with solid extracranial neoplasms were studied. All patients underwent a routine whole body (18)F-FDG PET/CT scan with the whole brain included in the scanned field. Patients with known or suspected brain metastases were preliminary excluded from the study. Hypermetabolic and ring-like brain lesions on the PET scan were considered as metastases. Lesions with CT characteristics of brain metastases were regarded as such irrespective of their metabolic pattern. Lesions in doubt were verified by MRI during first testing or on follow-up or by operation. Our results showed that brain lesions, indicative of and verified to be metastases were detected in 25 out of the 2502 patients (1%), with lung cancer being the most common primary. Twenty three out of these 25 patients had no neurological symptoms by the time of the scan. The detection rate of brain metastases was relatively low, but information was obtained with a minimum increase of radiation burden. In conclusion, whole body (18)F-FDG PET/CT detected brain metastases in 1% of the patients if brain was included in the scanned field. Brain

  17. Schwannoma Showing Avid Uptake on 68Ga-PSMA-HBED-CC PET/CT.

    PubMed

    Kanthan, Gowri L; Izard, Michael A; Emmett, Louise; Hsiao, Edward; Schembri, Geoffrey Paul

    2016-09-01

    Ga prostate-specific membrane antigen (PSMA) PET/CT is a relatively new and highly sensitive imaging modality used in staging metastatic prostate cancer. We report a case of a 65-year-old man with newly diagnosed prostate carcinoma who had a PSMA PET/CT scan for staging of his disease. A PSMA-avid right pelvic mass was identified anterior to the sacrum. Surgical removal and histopathological examination of this lesion revealed the diagnosis of schwannoma. It is important to be aware that schwannoma may also show avid uptake on PSMA PET/CT scan and may potentially lead to an incorrect diagnosis of metastatic prostate carcinoma. PMID:27405039

  18. Over-exposure correction in knee cone-beam CT imaging with automatic exposure control using a partial low dose scan

    NASA Astrophysics Data System (ADS)

    Choi, Jang-Hwan; Muller, Kerstin; Hsieh, Scott; Maier, Andreas; Gold, Garry; Levenston, Marc; Fahrig, Rebecca

    2016-03-01

    C-arm-based cone-beam CT (CBCT) systems with flat-panel detectors are suitable for diagnostic knee imaging due to their potentially flexible selection of CT trajectories and wide volumetric beam coverage. In knee CT imaging, over-exposure artifacts can occur because of limitations in the dynamic range of the flat panel detectors present on most CBCT systems. We developed a straightforward but effective method for correction and detection of over-exposure for an Automatic Exposure Control (AEC)-enabled standard knee scan incorporating a prior low dose scan. The radiation dose associated with the low dose scan was negligible (0.0042mSv, 2.8% increase) which was enabled by partially sampling the projection images considering the geometry of the knees and lowering the dose further to be able to just see the skin-air interface. We combined the line integrals from the AEC and low dose scans after detecting over-exposed regions by comparing the line profiles of the two scans detector row-wise. The combined line integrals were reconstructed into a volumetric image using filtered back projection. We evaluated our method using in vivo human subject knee data. The proposed method effectively corrected and detected over-exposure, and thus recovered the visibility of exterior tissues (e.g., the shape and density of the patella, and the patellar tendon), incorporating a prior low dose scan with a negligible increase in radiation exposure.

  19. Diagnostic capability of gadoxetate disodium-enhanced liver MRI for diagnosis of hepatocellular carcinoma: comparison with multi-detector CT.

    PubMed

    Toyota, Naoyuki; Nakamura, Yuko; Hieda, Masashi; Akiyama, Naoko; Terada, Hiroaki; Matsuura, Noriaki; Nishiki, Masayo; Kono, Hirotaka; Kohno, Hiroshi; Irei, Toshimitsu; Yoshikawa, Yukinobu; Kuraoka, Kazuya; Taniyama, Kiyomi; Awai, Kazuo

    2013-09-01

    The purpose of this study was to evaluate the diagnostic capability of gadoxetate disodium (Gd-EOB)-MRI for the detection of hepatocellular carcinoma (HCC) compared with multidetector CT (MDCT). Fifty patients with 57 surgically proven HCCs who underwent Gd-EOB-MRI and MDCT from March 2008 to June 2011 were evaluated. Two observers evaluated MR and CT on a lesion-by-lesion basis. We analyzed sensitivity by grading on a 5-point scale, the degree of arterial enhancement and the differences in histological grades in the diffusion-weighted images (DWI). The results showed that the sensitivity of Gd-EOB-MRI was higher than that of MDCT especially for HCCs that were 1 cm in diameter or smaller. The hepatobiliary phase was useful for the detecting of small HCC. We had few cases in which it was difficult to judge HCC in the arterial enhancement between MRI and MDCT. In the diffusion-weighted image, well differentiated HCC tended to show a low signal intensity, and poorly differentiated HCC tended to show a high signal intensity. In moderately differentiated HCC's, the mean diameter of the high signal intensity group was larger than that of the low signal intensity group (24.5 mm vs. 15.8 mm). In conclusion, Gd-EOB-MRI tended to show higher sensitivity compared to MDCT in the detection of HCC.

  20. Cone beam CT dosimetry: A unified and self-consistent approach including all scan modalities—With or without phantom motion

    PubMed Central

    Dixon, Robert L.; Boone, John M.

    2010-01-01

    Purpose: This article describes a common methodology and measurement technique, encompassing both conventional (helical and axial) CT scanning using phantom translation and cone beam (or narrow fan beam) CT scans about a stationary phantom. Cone beam CT systems having beam widths along the z-axis wide enough to cover a significant anatomical length (50–160 mm) in a single axial rotation (e.g., in cardiac CT) are rapidly proliferating in the clinic, referred to herein as stationary cone beam CT (SCBCT). The integral format of the CTDI paradigm is not appropriate for a stationary phantom, and is not useful for predicting the dose in SCBCT, nor for perfusion studies or CT fluoroscopy. Likewise, the pencil chamber has limited utility in this domain (even one of extended length). Methods: By demonstrating, both experimentally and theoretically, the match between the dose distribution f(z) for a wide cone beam and that due to an axial scan series D˜(z), it is shown that the dose on the central ray of the cone beam f(0) is both spatially colocated and numerically equal to the dose predicted by CTDI for the axial series; and thus f(0) is the logical (and unique) choice for a SCBCT dose-descriptor consistent with the CTDI-based dose of conventional CT. This dose f(0) can be readily measured using a conventional (short) ionization chamber. Additionally, Monte Carlo simulations of Boone [J. M. Boone, “Dose spread functions in computed tomography: A Monte Carlo study,” Med. Phys. 36, 4547–4554 (2009)], expressed as a scatter LSF (or DSF), allow the application of a convolution-based model [R. L. Dixon, M. T. Munley, and E. Bayram, “An improved analytical model for CT dose simulation with a new look at the theory of CT dose,” Med. Phys. 32, 3712–3728 (2005)] of the axial dose profile f(z) for any primary beam width a (anyn×T), fan beam and cone beam alike, from a single LSF kernel; its simple form allows the results to be expressed as simple analytical equations

  1. Prognostic value of pretreatment 18F-FDG PET-CT in radiotherapy for patients with hepatocellular carcinoma

    PubMed Central

    Jo, In Young; Son, Seok-Hyun; Kim, Myungsoo; Sung, Soo Yoon; Won, Yong Kyun; Kang, Hye Jin; Lee, So Jung; Chung, Yong-An; Oh, Jin Kyoung

    2015-01-01

    Purpose The purpose of this study was to investigate the predictable value of pretreatment 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) in radiotherapy (RT) for patients with hepatocellular carcinoma (HCC) or portal vein tumor thrombosis (PVTT). Materials and Methods We conducted a retrospective analysis of 36 stage I-IV HCC patients treated with RT. 18F-FDG PET-CT was performed before RT. Treatment target was determined HCC or PVTT lesions by treatment aim. They were irradiated at a median prescription dose of 50 Gy. The response was evaluated within 3 months after completion of RT using the Response Evaluation Criteria in Solid Tumors (RECIST). Response rate, overall survival (OS), and the pattern of failure (POF) were analyzed. Results The response rate was 61.1%. The statistically significant prognostic factor affecting response in RT field was maximal standardized uptake value (maxSUV) only. The high SUV group (maxSUV ≥ 5.1) showed the better radiologic response than the low SUV group (maxSUV < 5.1). The median OS were 996.0 days in definitive group and 144.0 days in palliative group. Factors affecting OS were the %reduction of alpha-fetoprotein (AFP) level in the definitive group and Child-Pugh class in the palliative group. To predict the POF, maxSUV based on the cutoff value of 5.1 was the only significant factor in distant metastasis group. Conclusion The results of this study suggest that the maxSUV of 18F-FDG PET-CT may be a prognostic factor for treatment outcome and the POF after RT. A %reduction of AFP level and Child-Pugh class could be used to predict OS in HCC. PMID:26484301

  2. What is currently the best radiopharmaceutical for the hybrid PET/CT detection of recurrent medullary thyroid carcinoma?

    PubMed

    Slavikova, K; Montravers, F; Treglia, G; Kunikowska, J; Kaliska, L; Vereb, M; Talbot, J N; Balogova, S

    2013-06-01

    Among thyroid malignancies, medullary thyroid carcinoma (MTC) has some very specific features. Production and secretion of large amounts of peptides occur in malignant transformed C cells with few exceptions, leading to high serum levels of calcitonin (Ctn) and carcinoembryonic antigen (CEA), that act after thyroidectomy as tumour markers warning for the presence of persistent or metastatic MTC. The availability of those serum biomarkers with an excellent sensitivity challenges medical imaging to localise the recurrent cancer tissue, since surgery is a major therapeutic option. The aims of this article are (i) to review literature evidence about the efficacy and tolerance of radiopharmaceuticals for 3 targets of PET/CT imaging (glucose metabolism, bioamines metabolism and somatostatin receptors) and also bone scintigraphy which is recommended in the Guidelines of European Society for Medical Oncology (ESMO; (ii) to compare the availability and the costs in relation with those radiopharmaceuticals, (iii) and to discuss a possible sequence of those examinations, in order to optimise spending and to minimise the overall radiation dose. In this context of recurrent MTC suspected on rising tumour markers levels after thyroidectomy, this survey of literature confirms that FDOPA is the best radiopharmaceutical for PET/CT with significant diagnostic performance if Ctn>150 pg/mL; an early image acquisition starting during the first 15 min is advised. In negative cases, FDG should be the next PET radiopharmaceutical, in particular if Ctn and CEA levels are rapidly rising, and PET with a somatostatin analogue labelled with gallium-68 when neither FDOPA nor FDG PET are conclusive. Bone scintigraphy could complement FDG-PET/CT if FDOPA is not available.

  3. Color intensity projections: A rapid approach for evaluating four-dimensional CT scans in treatment planning

    SciTech Connect

    Cover, Keith S.; Lagerwaard, Frank J.; Senan, Suresh . E-mail: s.senan@vumc.nl

    2006-03-01

    Purpose: Four-dimensional computerized tomography scans (4DCT) enable intrafractional motion to be determined. Because more than 1500 images can be generated with each 4DCT study, tools for efficient data visualization and evaluation are needed. We describe the use of color intensity projections (CIP) for visualizing mobility. Methods: Four-dimensional computerized tomography images of each patient slice were combined into a CIP composite image. Pixels largely unchanged over the component images appear unchanged in the CIP image. However, pixels whose intensity changes over the phases of the 4DCT appear in the CIP image as colored pixels, and the hue encodes the percentage of time the tissue was in each location. CIPs of 18 patients were used to study tumor and surrogate markers, namely the diaphragm and an abdominal marker block. Results: Color intensity projections permitted mobility of high-contrast features to be quickly visualized and measured. In three selected expiratory phases ('gating phases') that were reviewed in the sagittal plane, gating would have reduced mean tumor mobility from 6.3 {+-} 2.0 mm to 1.4 {+-} 0.5 mm. Residual tumor mobility in gating phases better correlated with residual mobility of the marker block than that of the diaphragm. Conclusion: CIPs permit immediate visualization of mobility in 4DCT images and simplify the selection of appropriate surrogates for gated radiotherapy.

  4. How parrots talk: insights based on CT scans, image processing, and mathematical models

    NASA Astrophysics Data System (ADS)

    Patterson, Dianne K.; Pepperberg, Irene M.; Story, Brad H.; Hoffman, Eric A.

    1997-05-01

    Little is known about mechanisms of speech production in parrots. Recently, however, techniques for correlating vocal tract shape with vowel production in humans have become more sophisticated and we have adapted these techniques for use with parrots. We scanned two grey parrot heads with intact vocal tracts. One specimen, 'Oldbird' was fixed with its beak propped open; the second 'Youngbird' was fixed with its beak closed. Using VIDA software, we (1) established that differences in tongue and larynx positioning resulted from opening or closing the beak; and (2) obtained lengths and area functions for the trachea, glottis, pharynx, mouth, and choana for both specimens and esophageal length and area functions for the first specimen. We entered lengths and area functions into a 1D wave propagation model to determine the natural formant frequencies associated with an open versus closed beak. We also determined how manipulating lengths and area functions could affect formant frequency and relative intensity. Finally, by comparing observed grey parrot vowel formant, we predict how the parrot uses its vocal tract to produce speech.

  5. Improved image quality of cone beam CT scans for radiotherapy image guidance using fiber-interspaced antiscatter grid

    SciTech Connect

    Stankovic, Uros; Herk, Marcel van; Ploeger, Lennert S.; Sonke, Jan-Jakob

    2014-06-15

    Purpose: Medical linear accelerator mounted cone beam CT (CBCT) scanner provides useful soft tissue contrast for purposes of image guidance in radiotherapy. The presence of extensive scattered radiation has a negative effect on soft tissue visibility and uniformity of CBCT scans. Antiscatter grids (ASG) are used in the field of diagnostic radiography to mitigate the scatter. They usually do increase the contrast of the scan, but simultaneously increase the noise. Therefore, and considering other scatter mitigation mechanisms present in a CBCT scanner, the applicability of ASGs with aluminum interspacing for a wide range of imaging conditions has been inconclusive in previous studies. In recent years, grids using fiber interspacers have appeared, providing grids with higher scatter rejection while maintaining reasonable transmission of primary radiation. The purpose of this study was to evaluate the impact of one such grid on CBCT image quality. Methods: The grid used (Philips Medical Systems) had ratio of 21:1, frequency 36 lp/cm, and nominal selectivity of 11.9. It was mounted on the kV flat panel detector of an Elekta Synergy linear accelerator and tested in a phantom and a clinical study. Due to the flex of the linac and presence of gridline artifacts an angle dependent gain correction algorithm was devised to mitigate resulting artifacts. Scan reconstruction was performed using XVI4.5 augmented with inhouse developed image lag correction and Hounsfield unit calibration. To determine the necessary parameters for Hounsfield unit calibration and software scatter correction parameters, the Catphan 600 (The Phantom Laboratory) phantom was used. Image quality parameters were evaluated using CIRS CBCT Image Quality and Electron Density Phantom (CIRS) in two different geometries: one modeling head and neck and other pelvic region. Phantoms were acquired with and without the grid and reconstructed with and without software correction which was adapted for the different

  6. Influence of 320-detector-row volume scanning and AAPM report 111 CT dosimetry metrics on size-specific dose estimate: a Monte Carlo study.

    PubMed

    Haba, Tomonobu; Koyama, Shuji; Kinomura, Yutaka; Ida, Yoshihiro; Kobayashi, Masanao

    2016-09-01

    The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDIvol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations. Simulations were performed modelling a Toshiba Aquilion ONE CT scanner, in order to compute dose values in water for cylindrical phantoms with 8-40-cm diameters at 2-cm intervals for each scanning parameter (tube voltage, bow-tie filter, longitudinal beam width). Then, the conversion factors were obtained by applying exponential regression analysis between the dose values for a given phantom diameter and the phantom diameter combined with various scanning parameters. The conversion factors for each scanning method (helical, axial, or volume scanning) and CT dosimetry method (i.e., the CTDI100 method or the AAPM task group 111 method) were in agreement with those reported by AAPM task group 204, within a percentage error of 14.2 % for phantom diameters ≥11.2 cm. The results obtained in this study indicate that the conversion factors previously presented by AAPM task group 204 can be used to provide appropriate SSDE values for 320-detector-row volume CT examinations and the CT dosimetry metrics proposed by the AAPM task group 111.

  7. Influence of 320-detector-row volume scanning and AAPM report 111 CT dosimetry metrics on size-specific dose estimate: a Monte Carlo study.

    PubMed

    Haba, Tomonobu; Koyama, Shuji; Kinomura, Yutaka; Ida, Yoshihiro; Kobayashi, Masanao

    2016-09-01

    The American Association of Physicists in Medicine (AAPM) task group 204 has recommended the use of size-dependent conversion factors to calculate size-specific dose estimate (SSDE) values from volume computed tomography dose index (CTDIvol) values. However, these conversion factors do not consider the effects of 320-detector-row volume computed tomography (CT) examinations or the new CT dosimetry metrics proposed by AAPM task group 111. This study aims to investigate the influence of these examinations and metrics on the conversion factors reported by AAPM task group 204, using Monte Carlo simulations. Simulations were performed modelling a Toshiba Aquilion ONE CT scanner, in order to compute dose values in water for cylindrical phantoms with 8-40-cm diameters at 2-cm intervals for each scanning parameter (tube voltage, bow-tie filter, longitudinal beam width). Then, the conversion factors were obtained by applying exponential regression analysis between the dose values for a given phantom diameter and the phantom diameter combined with various scanning parameters. The conversion factors for each scanning method (helical, axial, or volume scanning) and CT dosimetry method (i.e., the CTDI100 method or the AAPM task group 111 method) were in agreement with those reported by AAPM task group 204, within a percentage error of 14.2 % for phantom diameters ≥11.2 cm. The results obtained in this study indicate that the conversion factors previously presented by AAPM task group 204 can be used to provide appropriate SSDE values for 320-detector-row volume CT examinations and the CT dosimetry metrics proposed by the AAPM task group 111. PMID:27444155

  8. The Use of PET-CT in the Assessment of Patients with Colorectal Carcinoma

    PubMed Central

    O'Connor, Owen J.; McDermott, Shanaugh; Slattery, James; Sahani, Dushyant; Blake, Michael A.

    2011-01-01

    Colorectal cancer is the third most commonly diagnosed cancer, accounting for 53,219 deaths in 2007 and an estimated 146,970 new cases in the USA during 2009. The combination of FDG PET and CT has proven to be of great benefit for the assessment of colorectal cancer. This is most evident in the detection of occult metastases, particularly intra- or extrahepatic sites of disease, that would preclude a curative procedure or in the detection of local recurrence. FDG PET is generally not used for the diagnosis of colorectal cancer although there are circumstances where PET-CT may make the initial diagnosis, particularly with its more widespread use. In addition, precancerous adenomatous polyps can also be detected incidentally on whole-body images performed for other indications; sensitivity increases with increasing polyp size. False-negative FDG PET findings have been reported with mucinous adenocarcinoma, and false-positive findings have been reported due to inflammatory conditions such as diverticulitis, colitis, and postoperative scarring. Therefore, detailed evaluation of the CT component of a PET/CT exam, including assessment of the entire colon, is essential. PMID:22312527

  9. Virtual bite registration using intraoral digital scanning, CT and CBCT: In vitro evaluation of a new method and its implication for orthognathic surgery.

    PubMed

    Nilsson, Johanna; Richards, Robert Geoff; Thor, Andreas; Kamer, Lukas

    2016-09-01

    Three-dimensional (3D) computer-assisted planning requires detailed visualisation of the craniomaxillofacial region and interocclusal relationship. The aim of this study was to establish and evaluate a method to create a 3D model of the craniomaxillofacial region and to adopt intraoral digital scanning to place the lower jaw into a centric relation (CR) without the need of additional plaster casts and model surgery. A standard plastic skull modified by metallic dental wires and brackets was subjected to computed tomography (CT), cone beam computed tomography (CBCT), and intraoral digital scanning. We evaluated two different virtual bite registrations, a digital scan of the buccal dental surfaces and scanning of the wax bites to position the lower jaw into a CR, and assessed the accuracy of the integration of intraoral scanning to the CT/CBCT scans. The mean registration error of corresponding mesh points for the CT and intraoral scanned images was 0.15 ± 0.12 mm, while this error was 0.18 ± 0.13 mm for the CBCT and intraoral scanned images. The mean accuracy of the two virtual bite registrations ranged from 0.41 to 0.49 mm (buccal scan technique) and from 0.65 to 1.3 mm (virtualised wax bite technique). A method for virtual bite registration was developed. It has the potential to eliminate plaster casts and model surgery and may facilitate 3D computer-assisted planning of orthognathic surgery cases.

  10. Virtual bite registration using intraoral digital scanning, CT and CBCT: In vitro evaluation of a new method and its implication for orthognathic surgery.

    PubMed

    Nilsson, Johanna; Richards, Robert Geoff; Thor, Andreas; Kamer, Lukas

    2016-09-01

    Three-dimensional (3D) computer-assisted planning requires detailed visualisation of the craniomaxillofacial region and interocclusal relationship. The aim of this study was to establish and evaluate a method to create a 3D model of the craniomaxillofacial region and to adopt intraoral digital scanning to place the lower jaw into a centric relation (CR) without the need of additional plaster casts and model surgery. A standard plastic skull modified by metallic dental wires and brackets was subjected to computed tomography (CT), cone beam computed tomography (CBCT), and intraoral digital scanning. We evaluated two different virtual bite registrations, a digital scan of the buccal dental surfaces and scanning of the wax bites to position the lower jaw into a CR, and assessed the accuracy of the integration of intraoral scanning to the CT/CBCT scans. The mean registration error of corresponding mesh points for the CT and intraoral scanned images was 0.15 ± 0.12 mm, while this error was 0.18 ± 0.13 mm for the CBCT and intraoral scanned images. The mean accuracy of the two virtual bite registrations ranged from 0.41 to 0.49 mm (buccal scan technique) and from 0.65 to 1.3 mm (virtualised wax bite technique). A method for virtual bite registration was developed. It has the potential to eliminate plaster casts and model surgery and may facilitate 3D computer-assisted planning of orthognathic surgery cases. PMID:27423538

  11. Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans

    SciTech Connect

    Okada, Kazunori; Rysavy, Steven; Flores, Arturo; Linguraru, Marius George

    2015-04-15

    Purpose: This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. Methods: The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. Results: A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon’s state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Conclusions: Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon’s conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.

  12. Differentiation of complicated cholecystitis from gallbladder carcinoma by computed tomography

    SciTech Connect

    Smathers, R.L.; Lee, J.K.T.; Heiken, J.P.

    1984-08-01

    Differentiation between complicated cholecystitis and advanced gallbladder carcinoma can be difficult when clinical findings are confusing. Computed tomographic (CT) scans were reviewed from 22 patients with a surgical diagnosis of complicated cholecystitis (11 cases) or advanced gallbladder carcinoma (11 cases). The presence of a curvilinear low-attenuation halo around the gallbladder wall was specific for complicated cholecystitis. Findings indicative of gallbladder carcinoma included a focal soft-invasion or metastases. Knowledge of these differential CT findings may result in a more accurate preoperative diagnosis.

  13. Feasibility of CT-based 3D anatomic mapping with a scanning-beam digital x-ray (SBDX) system

    NASA Astrophysics Data System (ADS)

    Slagowski, Jordan M.; Tomkowiak, Michael T.; Dunkerley, David A. P.; Speidel, Michael A.

    2015-03-01

    This study investigates the feasibility of obtaining CT-derived 3D surfaces from data provided by the scanning-beam digital x-ray (SBDX) system. Simulated SBDX short-scan acquisitions of a Shepp-Logan and a thorax phantom containing a high contrast spherical volume were generated. 3D reconstructions were performed using a penalized weighted least squares method with total variation regularization (PWLS-TV), as well as a more efficient variant employing gridding of projection data to parallel rays (gPWLS-TV). Voxel noise, edge blurring, and surface accuracy were compared to gridded filtered back projection (gFBP). PWLS reconstruction of a noise-free reduced-size Shepp-Logan phantom had 1.4% rRMSE. In noisy gPWLS-TV reconstructions of a reduced-size thorax phantom, 99% of points on the segmented sphere perimeter were within 0.33, 0.47, and 0.70 mm of the ground truth, respectively, for fluences comparable to imaging through 18.0, 27.2, and 34.6 cm acrylic. Surface accuracies of gFBP and gPWLS-TV were similar at high fluences, while gPWLS-TV offered improvement at the lowest fluence. The gPWLS-TV voxel noise was reduced by 60% relative to gFBP, on average. High-contrast linespread functions measured 1.25 mm and 0.96 mm (FWHM) for gPWLS-TV and gFBP. In a simulation of gated and truncated projection data from a full-sized thorax, gPWLS-TV reconstruction yielded segmented surface points which were within 1.41 mm of ground truth. Results support the feasibility of 3D surface segmentation with SBDX. Further investigation of artifacts caused by data truncation and patient motion is warranted.

  14. SU-E-I-48: The Behavior of AEC in Scan Regions Outside the Localizer Radiograph FOV: An In Phantom Study of CT Systems From Four Vendors

    SciTech Connect

    Supanich, M; Bevins, N

    2014-06-01

    Purpose: This review of scanners from 4 major manufacturers examines the clinical impact of performing CT scans that extend into areas of the body that were not acquired in the CT localizer radiograph. Methods: Anthropomorphic chest and abdomen phantoms were positioned together on the tables of CT scanners from 4 different vendors. All of the scanners offered an Automatic Exposure Control (AEC) option with both lateral and axial tube current modulation. A localizer radiograph was taken covering the entire extent of both phantoms and then the scanner's Chest-Abdomen-Pelvis (CAP) study was performed with the clinical AEC settings employed and the scan and reconstruction range extending from the superior portion of the chest phantom through the inferior portion of the abdomen phantom. A new study was then initiated with a localizer radiograph extending the length of the chest phantom (not covering the abdomen phantom). The same CAP protocol and AEC settings were then used to scan and reconstruct the entire length of both phantoms. Scan parameters at specific locations in the abdomen phantom from both studies were investigated using the information contained in the DICOM metadata of the reconstructed images. Results: The AEC systems on all scanners utilized different tube current settings in the abdomen phantom for the scan completed without the full localizer radiograph. The AEC system behavior was also scanner dependent with the default manual tube current, the maximum tube current and the tube current at the last known position observed as outcomes. Conclusion: The behavior of the AEC systems of CT scanners in regions not covered by the localizer radiograph is vendor dependent. To ensure optimal image quality and radiation exposure it is important to include the entire planned scan region in the localizer radiograph.

  15. Multimodality Fusion with MRI, CT, and Ultrasound Contrast for Ablation of Renal Cell Carcinoma.

    PubMed

    Amalou, Hayet; Wood, Bradford J

    2012-01-01

    Fusion technology with electromagnetic (EM) tracking enables navigation with multimodality feedback that lets the operator use different modalities during different parts of the image-guided procedure. This may be particularly helpful in patients with renal insufficiency undergoing kidney tumor ablation, in whom there is a desire to minimize or avoid nephrotoxic iodinated contrast exposure. EM tracking software merges and fuses different imaging modalities such as MRI, CT, and ultrasound and can also display the position of needles in real time in relation to preprocedure imaging, which may better define tumor targets than available intraoperative imaging. EM tracking was successfully used to ablate a poorly visualized renal tumor, through the combined use of CT, gadolinium-enhanced MR, and contrast-enhanced US imaging to localize the tumor. PMID:23304625

  16. Whole body diffusion for metastatic disease assessment in neuroendocrine carcinomas: comparison with OctreoScan® in two cases

    PubMed Central

    2012-01-01

    Neuroendocrine tumor (NET) patients must be adequately staged in order to improve a multidisciplinary approach and optimal management for metastatic disease. Currently available imaging studies include somatostatin receptor scintigraphy, like OctreoScan®, computed tomography (CT), scans and magnetic resonance imaging (MRI), which analyze vascular concentration and intravenous contrast enhancement for anatomic tumor localization. However, these techniques require high degree of expertise for interpretation and are limited by their availability, cost, reproducibility, and follow-up imaging comparisons. NETs significantly reduce water diffusion as compared to normal tissue. Diffusion-weighted imaging (DWI) in MRI has an advantageous contrast difference: the tumor is represented with high signal over a black normal surrounding background. The whole-body diffusion (WBD) technique has been suggested to be a useful test for detecting metastasis from various anatomic sites. In this article we report the use of DWI in MRI and WBD in two cases of metastatic pulmonary NET staging in comparison with OctreoScan® in order to illustrate the potential advantage of DWI and WBD in staging NETs. PMID:22591909

  17. Multimodality Imaging in Pediatric Osteosarcoma in the Era of Image Gently and Image Wisely Campaign With a Close Look at the CT Scan Radiation Dose.

    PubMed

    Vijayakumar, Vani; Collier, Anderson B; Ruan, Chun; Zhang, Xu; Lowery, Rachel; Barr, Jennifer; Hicks, Chindo; Megason, Gail; Vijayakumar, Srinivasan

    2016-04-01

    The increasing use of serial multimodality imaging in the management of pediatric osteosarcoma raises concern of over exposure to ionizing radiation in children, especially from repeated computed tomographic (CT) scans. This study reviews the utilization of multimodality imaging in patients with osteosarcoma at our institution and analyzes any potential radiation-related complications. Twenty-eight patients were identified. Three patients developed late complications-acute myeloid leukemia, myelodysplastic syndrome, and early menopause. Using the patient's age and body part imaged, CT dose length product and effective dose was estimated with the use of a conversion factor for 19 patients. The effective doses were higher in the 3 patients with late complications than the other patients in the cohort (P=0.018). These results suggest an increased risk for adverse effects with higher CT exposures and effective doses. On the basis of our data and published data, methods to decrease the doses of radiation from medical imaging need to be explored. The number of CT scans may be limited. Implementing the Image Gently concept to decrease radiation exposure can be beneficial in modification of CT acquisition parameters. PMID:26583624

  18. An optimal set of landmarks for metopic craniosynostosis diagnosis from shape analysis of pediatric CT scans of the head

    NASA Astrophysics Data System (ADS)

    Mendoza, Carlos S.; Safdar, Nabile; Myers, Emmarie; Kittisarapong, Tanakorn; Rogers, Gary F.; Linguraru, Marius George

    2013-02-01

    Craniosynostosis (premature fusion of skull sutures) is a severe condition present in one of every 2000 newborns. Metopic craniosynostosis, accounting for 20-27% of cases, is diagnosed qualitatively in terms of skull shape abnormality, a subjective call of the surgeon. In this paper we introduce a new quantitative diagnostic feature for metopic craniosynostosis derived optimally from shape analysis of CT scans of the skull. We built a robust shape analysis pipeline that is capable of obtaining local shape differences in comparison to normal anatomy. Spatial normalization using 7-degree-of-freedom registration of the base of the skull is followed by a novel bone labeling strategy based on graph-cuts according to labeling priors. The statistical shape model built from 94 normal subjects allows matching a patient's anatomy to its most similar normal subject. Subsequently, the computation of local malformations from a normal subject allows characterization of the points of maximum malformation on each of the frontal bones adjacent to the metopic suture, and on the suture itself. Our results show that the malformations at these locations vary significantly (p<0.001) between abnormal/normal subjects and that an accurate diagnosis can be achieved using linear regression from these automatic measurements with an area under the curve for the receiver operating characteristic of 0.97.

  19. Mediastinal lymph node detection on thoracic CT scans using spatial prior from multi-atlas label fusion

    NASA Astrophysics Data System (ADS)

    Liu, Jiamin; Zhao, Jocelyn; Hoffman, Joanne; Yao, Jianhua; Zhang, Weidong; Turkbey, Evrim B.; Wang, Shijun; Kim, Christine; Summers, Ronald M.

    2014-03-01

    Lymph nodes play an important role in clinical practice but detection is challenging due to low contrast surrounding structures and variable size and shape. We propose a fully automatic method for mediastinal lymph node detection on thoracic CT scans. First, lungs are automatically segmented to locate the mediastinum region. Shape features by Hessian analysis, local scale, and circular transformation are computed at each voxel. Spatial prior distribution is determined based on the identification of multiple anatomical structures (esophagus, aortic arch, heart, etc.) by using multi-atlas label fusion. Shape features and spatial prior are then integrated for lymph node detection. The detected candidates are segmented by curve evolution. Characteristic features are calculated on the segmented lymph nodes and support vector machine is utilized for classification and false positive reduction. We applied our method to 20 patients with 62 enlarged mediastinal lymph nodes. The system achieved a significant improvement with 80% sensitivity at 8 false positives per patient with spatial prior compared to 45% sensitivity at 8 false positives per patient without a spatial prior.

  20. Emphysema quantification from CT scans using novel application of diaphragm curvature estimation: comparison with standard quantification methods and pulmonary function data

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Yankelevitz, David F.; Henschke, Claudia I.; Barr, R. Graham

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for the imaging of the anatomical basis of emphysema and quantification of the underlying disease state. Several measures have been introduced for the quantification emphysema directly from CT data; most,however, are based on the analysis of density information provided by the CT scans, which vary by scanner and can be hard to standardize across sites and time. Given that one of the anatomical variations associated with the progression of emphysema is the flatting of the diaphragm due to the loss of elasticity in the lung parenchyma, curvature analysis of the diaphragm would provide information about emphysema from CT. Therefore, we propose a new, non-density based measure of the curvature of the diaphragm that would allow for further quantification methods in a robust manner. To evaluate the new method, 24 whole-lung scans were analyzed using the ratios of the lung height and diaphragm width to diaphragm height as curvature estimates as well as using the emphysema index as comparison. Pearson correlation coefficients showed a strong trend of several of the proposed diaphragm curvature measures to have higher correlations, of up to r=0.57, with DLCO% and VA than did the emphysema index. Furthermore, we found emphysema index to have only a 0.27 correlation to the proposed measures, indicating that the proposed measures evaluate different aspects of the disease.

  1. US-CT 3D dual imaging by mutual display of the same sections for depicting minor changes in hepatocellular carcinoma.

    PubMed

    Fukuda, Hiroyuki; Ito, Ryu; Ohto, Masao; Sakamoto, Akio; Otsuka, Masayuki; Togawa, Akira; Miyazaki, Masaru; Yamagata, Hitoshi

    2012-09-01

    The purpose of this study was to evaluate the usefulness of ultrasound-computed tomography (US-CT) 3D dual imaging for the detection of small extranodular growths of hepatocellular carcinoma (HCC). The clinical and pathological profiles of 10 patients with single nodular type HCC with extranodular growth (extranodular growth) who underwent a hepatectomy were evaluated using two-dimensional (2D) ultrasonography (US), three-dimensional (3D) US, 3D computed tomography (CT) and 3D US-CT dual images. Raw 3D data was converted to DICOM (Digital Imaging and Communication in Medicine) data using Echo to CT (Toshiba Medical Systems Corp., Tokyo, Japan), and the 3D DICOM data was directly transferred to the image analysis system (ZioM900, ZIOSOFT Inc., Tokyo, Japan). By inputting the angle number (x, y, z) of the 3D CT volume data into the ZioM900, multiplanar reconstruction (MPR) images of the 3D CT data were displayed in a manner such that they resembled the conventional US images. Eleven extranodular growths were detected pathologically in 10 cases. 2D US was capable of depicting only 2 of the 11 extranodular growths. 3D CT was capable of depicting 4 of the 11 extranodular growths. On the other hand, 3D US was capable of depicting 10 of the 11 extranodular growths, and 3D US-CT dual images, which enable the dual analysis of the CT and US planes, revealed all 11 extranodular growths. In conclusion, US-CT 3D dual imaging may be useful for the detection of small extranodular growths.

  2. Feasibility of quantitative lung perfusion by 4D CT imaging by a new dynamic-scanning protocol in an animal model

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Goldin, Jonathan G.; Abtin, Fereidoun G.; Brown, Matt; McNitt-Gray, Mike

    2008-03-01

    The purpose of this study is to test a new dynamic Perfusion-CT imaging protocol in an animal model and investigate the feasibility of quantifying perfusion of lung parenchyma to perform functional analysis from 4D CT image data. A novel perfusion-CT protocol was designed with 25 scanning time points: the first at baseline and 24 scans after a bolus injection of contrast material. Post-contrast CT scanning images were acquired with a high sampling rate before the first blood recirculation and then a relatively low sampling rate until 10 minutes after administrating contrast agent. Lower radiation techniques were used to keep the radiation dose to an acceptable level. 2 Yorkshire swine with pulmonary emboli underwent this perfusion- CT protocol at suspended end inspiration. The software tools were designed to measure the quantitative perfusion parameters (perfusion, permeability, relative blood volume, blood flow, wash-in & wash-out enhancement) of voxel or interesting area of lung. The perfusion values were calculated for further lung functional analysis and presented visually as contrast enhancement maps for the volume being examined. The results show increased CT temporal sampling rate provides the feasibility of quantifying lung function and evaluating the pulmonary emboli. Differences between areas with known perfusion defects and those without perfusion defects were observed. In conclusion, the techniques to calculate the lung perfusion on animal model have potential application in human lung functional analysis such as evaluation of functional effects of pulmonary embolism. With further study, these techniques might be applicable in human lung parenchyma characterization and possibly for lung nodule characterization.

  3. College of Radiology, Academy of Medicine of Malaysia position on whole body screening CT scans in healthy asymptomatic individuals (2008)

    PubMed Central

    Ho, ELM; Abdullah, BJJ; Tang, AAL; Nordin, AJ; Nair, AR; Lim, GCC; Samad-Cheung, H; Ng, KH; Ponnusamy, S; Abbas, SF; Bux, SI; Arasaratnam, S; Abdul Aziz, YF; Venugopal, S; Musa, Z; Abdul Manaf, Z

    2008-01-01

    To date, the College of Radiology (CoR) does not see any clear benefit in performing whole body screening computed tomography (CT) examinations in healthy asymptomatic individuals. There are radiation risk issues in CT and principles of screening should be adhered to. There may be a role for targeted cardiac screening CT that derives calcium score, especially for asymptomatic medium-risk individuals and CT colonography when used as part of a strategic programme for colorectal cancer screening in those 50 years and older. However, population based screening CT examinations may become appropriate when evidence emerges regarding a clear benefit for the patient outweighing the associated radiation risks. PMID:21611021

  4. Metastatic Neuroendocrine Carcinoma of the Breast Identified by Tc-99m-HYNIC-TOC SPECT/CT: A Rare Case Report.

    PubMed

    Claimon, Apichaya; Chuthapisith, Suebwong; Samarnthai, Norasate; Pusuwan, Pawana

    2015-08-01

    The authors reported an uncommon presentation of metastatic neuroendocrine carcinoma to the breast detected by Tc-99m-HYNIC-TOC SPECT/CT in a 49 years old woman who, previously, had carcinoid tumor of left main bronchus and invasive ductal carcinoma of the right breast. Later, the patient developed left breast mass. Core needle biopsy of the mass revealed poorly differentiated invasive ductal carcinoma. The disease remained stable for 12 years without any treatment on that left breast (due to patient's rejection). On the later investigation using Tc-99m-HYNIC-TOC scintigraphy examination, rather than invasive ductal carcinoma, metastatic neuroendocrine cancer was suggested. The final diagnosis was confirmed by pathological examination after surgical excision. Multiple metastatic lesions of neuroendocrine carcinoma at lung, liver, ovaries, and bones were also depicted. Due to the good behavior of the disease, patient had been doing well for eight months, without specific treatment. This report confirmed the advantage and the accuracy of Tc-99m-HYNIC-TOC scintigraphy in detection of neuroendocrine carcinoma. Furthermore, metastatic neuroendocrine tumor should be in differential diagnosis for patient with breast mass together with history of neuroendocrine tumor

  5. Attenuation-based estimation of patient size for the purpose of size specific dose estimation in CT. Part II. Implementation on abdomen and thorax phantoms using cross sectional CT images and scanned projection radiograph images

    SciTech Connect

    Wang Jia; Christner, Jodie A.; Duan Xinhui; Leng Shuai; Yu Lifeng; McCollough, Cynthia H.

    2012-11-15

    Purpose: To estimate attenuation using cross sectional CT images and scanned projection radiograph (SPR) images in a series of thorax and abdomen phantoms. Methods: Attenuation was quantified in terms of a water cylinder with cross sectional area of A{sub w} from both the CT and SPR images of abdomen and thorax phantoms, where A{sub w} is the area of a water cylinder that would absorb the same dose as the specified phantom. SPR and axial CT images were acquired using a dual-source CT scanner operated at 120 kV in single-source mode. To use the SPR image for estimating A{sub w}, the pixel values of a SPR image were calibrated to physical water attenuation using a series of water phantoms. A{sub w} and the corresponding diameter D{sub w} were calculated using the derived attenuation-based methods (from either CT or SPR image). A{sub w} was also calculated using only geometrical dimensions of the phantoms (anterior-posterior and lateral dimensions or cross sectional area). Results: For abdomen phantoms, the geometry-based and attenuation-based methods gave similar results for D{sub w}. Using only geometric parameters, an overestimation of D{sub w} ranging from 4.3% to 21.5% was found for thorax phantoms. Results for D{sub w} using the CT image and SPR based methods agreed with each other within 4% on average in both thorax and abdomen phantoms. Conclusions: Either the cross sectional CT or SPR images can be used to estimate patient attenuation in CT. Both are more accurate than use of only geometrical information for the task of quantifying patient attenuation. The SPR based method requires calibration of SPR pixel values to physical water attenuation and this calibration would be best performed by the scanner manufacturer.

  6. Ultra-low-dose dual-source CT coronary angiography with high pitch: diagnostic yield of a volumetric planning scan and effects on dose reduction and imaging strategy

    PubMed Central

    Hamm, B; Huppertz, A; Lembcke, A

    2015-01-01

    Objective: To evaluate the role of an ultra-low-dose dual-source CT coronary angiography (CTCA) scan with high pitch for delimiting the range of the subsequent standard CTCA scan. Methods: 30 patients with an indication for CTCA were prospectively examined using a two-scan dual-source CTCA protocol (2.0 × 64.0 × 0.6 mm; pitch, 3.4; rotation time of 280 ms; 100 kV): Scan 1 was acquired with one-fifth of the tube current suggested by the automatic exposure control software [CareDose 4D™ (Siemens Healthcare, Erlangen, Germany) using 100 kV and 370 mAs as a reference] with the scan length from the tracheal bifurcation to the diaphragmatic border. Scan 2 was acquired with standard tube current extending with reduced scan length based on Scan 1. Nine central coronary artery segments were analysed qualitatively on both scans. Results: Scan 2 (105.1 ± 10.1 mm) was significantly shorter than Scan 1 (127.0 ± 8.7 mm). Image quality scores were significantly better for Scan 2. However, in 5 of 6 (83%) patients with stenotic coronary artery disease, a stenosis was already detected in Scan 1 and in 13 of 24 (54%) patients with non-stenotic coronary arteries, a stenosis was already excluded by Scan 1. Using Scan 2 as reference, the positive- and negative-predictive value of Scan 1 was 83% (5 of 6 patients) and 100% (13 of 13 patients), respectively. Conclusion: An ultra-low-dose CTCA planning scan enables a reliable scan length reduction of the following standard CTCA scan and allows for correct diagnosis in a substantial proportion of patients. Advances in knowledge: Further dose reductions are possible owing to a change in the individual patient's imaging strategy as a prior ultra-low-dose CTCA scan may already rule out the presence of a stenosis or may lead to a direct transferal to an invasive catheter procedure. PMID:25710210

  7. TU-C-12A-12: Differentiating Bone Lesions and Degenerative Joint Disease in NaF PET/CT Scans Using Machine Learning

    SciTech Connect

    Perk, T; Bradshaw, T; Muzahir, S; Jeraj, R; Meyer, E

    2014-06-15

    Purpose: [F-18]NaF PET can be used to image bone metastases; however, tracer uptake in degenerative joint disease (DJD) often appears similar to metastases. This study aims to develop and compare different machine learning algorithms to automatically identify regions of [F-18]NaF scans that correspond to DJD. Methods: 10 metastatic prostate cancer patients received whole body [F-18]NaF PET/CT scans prior to treatment. Image segmentation resulted in 852 ROIs, 69 of which were identified by a nuclear medicine physician as DJD. For all ROIs, various PET and CT textural features were computed. ROIs were divided into training and testing sets used to train eight different machine learning classifiers. Classifiers were evaluated based on receiver operating characteristics area under the curve (AUC), sensitivity, specificity, and positive predictive value (PPV). We also assessed the added value of including CT features in addition to PET features for training classifiers. Results: The training set consisted of 37 DJD ROIs with 475 non-DJD ROIs, and the testing set consisted of 32 DJD ROIs with 308 non-DJD ROIs. Of all classifiers, generalized linear models (GLM), decision forests (DF), and support vector machines (SVM) had the best performance. AUCs of GLM (0.929), DF (0.921), and SVM (0.889) were significantly higher than the other models (p<0.001). GLM and DF, overall, had the best sensitivity, specificity, and PPV, and gave a significantly better performance (p<0.01) than all other models. PET/CT GLM classifiers had higher AUC than just PET or just CT. GLMs built using PET/CT information had superior or comparable sensitivities, specificities and PPVs to just PET or just CT. Conclusion: Machine learning algorithms trained with PET/CT features were able to identify some cases of DJD. GLM outperformed the other classification algorithms. Using PET and CT information together was shown to be superior to using PET or CT features alone. Research supported by the Prostate

  8. Beam-specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors.

    PubMed

    Lin, Liyong; Kang, Minglei; Huang, Sheng; Mayer, Rulon; Thomas, Andrew; Solberg, Timothy D; McDonough, James E; Simone, Charles B

    2015-11-08

    The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using ± 3% uncertainty in stopping power and ± 3 mm uncertainty in patient setup in each direction, were used to create 8 × 12 × 10 = 960 PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p-values <0.05, with the exception of the heart V45 (p = 0.146). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion-related uncertainties is essential.

  9. Beam-specific planning target volumes incorporating 4D CT for pencil beam scanning proton therapy of thoracic tumors.

    PubMed

    Lin, Liyong; Kang, Minglei; Huang, Sheng; Mayer, Rulon; Thomas, Andrew; Solberg, Timothy D; McDonough, James E; Simone, Charles B

    2015-01-01

    The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties, and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4D CT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4D CT phases, using ± 3% uncertainty in stopping power and ± 3 mm uncertainty in patient setup in each direction, were used to create 8 × 12 × 10 = 960 PBS plans for the evaluation of 10 patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and V45 were reduced from 10.4% and 7.5% in DS to 8.1% and 5.4% for PBS, respectively. Furthermore, the maximum spinal cord, esophagus, and heart doses were decreased from 37.1 Gy, 71.7 Gy, and 69.2 Gy with DS to 31.3 Gy, 67.9 Gy, and 64.6 Gy with PBS. The conformity index (CI), homogeneity index (HI), and global maximal dose were improved from 3.2, 0.08, 77.4 Gy with DS to 2.8, 0.04, and 72.1 Gy with PBS. All differences are statistically significant, with p-values <0.05, with the exception of the heart V45 (p = 0.146). PBS with BSPTV achieves better organ sparing and improves target coverage using a repainting method for the treatment of thoracic tumors. Incorporating motion-related uncertainties is essential. PMID:26699580

  10. Diagnostic performance of gadoxetic acid (Primovist)-enhanced MR imaging versus CT during hepatic arteriography and portography for small hypervascular hepatocellular carcinoma.

    PubMed

    Yim, Sun Young; Park, Beom Jin; Um, Soon Ho; Han, Na Yeon; Sung, Deuk Jae; Cho, Sung Bum; Lee, Seung Hwa; Kim, Min Ju; Jung, Jin Yong; Kim, Jin Dong; Seo, Yeon Seok; Kim, Dong Sik; An, Hyonggin; Kim, Yun Hwan

    2016-09-01

    To compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with that of computed tomography (CT) during hepatic arteriography and arterial portography (CT HA/AP) for detecting hepatocellular carcinoma (HCC) from small hypervascular nodules.This retrospective study included 38 patients with 131 hypervascular nodules (≤2 cm) who had underwent MRI and CT HA/AP within a 2-week interval. Two observers analyzed MRI while other 2 observers analyzed CT HA/AP. Thereafter, MRI observers reviewed the CT HA/AP and magnetic resonance (MR) images again using both modalities. HCC was diagnosed by pathologic or imaging studies according to American Association for the Study of Liver Diseases (AASLD) criteria. Alternative free-response receiver operating characteristic (ROC) analysis was performed on a lesion-by-lesion basis. Diagnostic accuracy (area under the ROC curve [Az]), sensitivity, specificity, and positive and negative predictive values were calculated.The pooled Az was significantly higher for the combined modalities (0.946) than for MRI alone (0.9, P = 0.004), and for MRI than for CT HA/AP alone (0.827, P = 0.0154). Subgroup analysis for HCC ≤1 cm showed the sensitivity of the combined modalities (79.4%) was significantly higher than for MRI (52.9%) and CT HA/AP alone (50%) (both, P < 0.005). The specificity of the combined modalities was not different from MRI alone (98.8% vs. 97.3%, P = 0.5), but was significantly higher than for CT HA/AP alone (98.8% vs. 92.5%, P = 0.022).Hypervascular HCCs >1 to 2 cm can be diagnosed sufficiently by MRI. The combined modalities increased the diagnostic accuracy of HCCs ≤1 cm, compared with MRI or CT HA/AP alone. PMID:27684824

  11. Role of C-Arm Cone-Beam CT in Chemoembolization for Hepatocellular Carcinoma

    PubMed Central

    2015-01-01

    With the advent of C-arm cone-beam computed tomography (CBCT), minimally-invasive procedures in the angiography suite made a new leap beyond the limitations of 2-dimensional (D) angiography alone. C-arm CBCT can help interventional radiologists in several ways with the treatment of hepatocellular carcinoma (HCC); visualization of small tumors and tumor-feeding arteries, identification of occult lesion and 3D configuration of tortuous hepatic arteries, assurance of completeness of chemoembolization, suggestion of presence of extrahepatic collateral arteries supplying HCCs, and prevention of nontarget embolization. With more improvements in the technology, C-arm CBCT may be essential in all kinds of interventional procedures in the near future. PMID:25598679

  12. Role of C-arm cone-beam CT in chemoembolization for hepatocellular carcinoma.

    PubMed

    Kim, Hyo-Cheol

    2015-01-01

    With the advent of C-arm cone-beam computed tomography (CBCT), minimally-invasive procedures in the angiography suite made a new leap beyond the limitations of 2-dimensional (D) angiography alone. C-arm CBCT can help interventional radiologists in several ways with the treatment of hepatocellular carcinoma (HCC); visualization of small tumors and tumor-feeding arteries, identification of occult lesion and 3D configuration of tortuous hepatic arteries, assurance of completeness of chemoembolization, suggestion of presence of extrahepatic collateral arteries supplying HCCs, and prevention of nontarget embolization. With more improvements in the technology, C-arm CBCT may be essential in all kinds of interventional procedures in the near future.

  13. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    SciTech Connect

    Sommer, C. M.; Lemm, G.; Hohenstein, E.; Bellemann, N.; Stampfl, U.; Goezen, A. S.; Rassweiler, J.; Kauczor, H. U.; Radeleff, B. A.; Pereira, P. L.

    2013-06-15

    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  14. Application of 18F-FDG PET/CT combined with carbohydrate antigen 19-9 for differentiating pancreatic carcinoma from chronic mass-forming pancreatitis in Chinese elderly

    PubMed Central

    Gu, Xinjin; Liu, Rong

    2016-01-01

    Objective The current study was designed to analyze the value of 18F-FDG positron emission tomography/computed tomography (PET/CT) combined with carbohydrate antigen 19-9 (CA19-9) in differentiating pancreatic carcinoma (PC) from chronic mass-forming pancreatitis (CMFP) in Chinese elderly. Methods As it is impossible to differentially diagnose PC from CMFP, 60 participants older than 65 years with focal pancreatic lesions were scanned by 18F-FDG PET/CT and their CA19-9 levels were tested. Diagnoses of all participants were confirmed by comprehensive methods including aspiration biopsy, surgical pathology, and clinical follow-up of 12 months. Twenty participants with CMFP were included in CMFP group and 40 participants with PC in PC group. Results In CMFP and PC groups, 46 participants showed increased 18F-FDG uptake, 43 had elevated CA19-9 levels, and 38 participants had both increased 18F-FDG uptake and elevated CA19-9 levels. Standardized uptake value maximum of PC group (5.98±2.27) was significantly different from CMFP group (2.58±1.81, P<0.05). Sensitivity, specificity, and accuracy of 18F-FDG PET/CT in differentiating PC from CMFP were 95%, 60%, and 83.3%, respectively. CA19-9 levels of PC group (917.44±1,088.24) were significantly different from CMFP group (19.09±19.54, P<0.05). Sensitivity, specificity, and accuracy of CA19-9 levels in differentiating PC from CMFP were 87.5%, 60%, and 78.3%, respectively. Sensitivity, specificity, and accuracy of 18F-FDG PET/CT combined with CA19-9 levels in differentiating PC from CMFP were 90%, 90%, and 90%, respectively. Conclusion 18F-FDG PET/CT had reliable sensitivity, specificity, and accuracy in differentiating PC from CMFP, and CA19-9 levels could be helpful in 18F-FDG PET/CT for differentiating PC from CMFP in Chinese elderly. Moreover, 18F-FDG PET/CT combined with CA19-9 levels was found to be an effective method to differentially diagnose PC from CMFP and has paved the way for the timely and safe treatment of

  15. Thoracic spine CT scan

    MedlinePlus

    ... helps certain areas show up better on the x-rays. Contrast can be given in several ways. It may be given as an injection through: A vein (IV) in your hand or forearm. Your back into the space surrounding the spinal cord. If contrast is used, ...

  16. Lumbar spine CT scan

    MedlinePlus

    ... helps certain areas show up better on the x-rays. Contrast can be given in different ways. It may be given through a vein (IV) in your hand or forearm. It may be given as an injection into the space around the spinal cord. If contrast is used, ...

  17. Shoulder CT scan

    MedlinePlus

    ... type of contrast given into a vein contains iodine. If a person with an iodine allergy is given this type of contrast, nausea ... steroids before the test. The kidneys help remove iodine out of the body. Those with kidney disease ...

  18. Heart CT scan

    MedlinePlus

    ... type of contrast given into a vein contains iodine. If a person with an iodine allergy is given this type of contrast, nausea ... steroids before the test. The kidneys help remove iodine out of the body. Those with kidney disease ...

  19. Cervical spine CT scan

    MedlinePlus

    ... type of contrast given into a vein contains iodine. If a person with an iodine allergy is given this type of contrast, nausea ... steroids before the test. The kidneys help remove iodine out of the body. People with kidney disease ...

  20. Sinus CT scan

    MedlinePlus

    ... of Medical Imaging . 6th ed. New York, NY: Churchill Livingstone; 2014:chap 67. Shaw AS, Dixon AK. ... of Medical Imaging . 5th ed. New York, NY: Churchill Livingstone; 2008:chap 4. Thomsen HS, Reimer P. ...

  1. Knee CT scan

    MedlinePlus

    ... are inside the scanner, the machine's x-ray beam rotates around you. (Modern "spiral" scanners can perform ... Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. ...

  2. Arm CT scan

    MedlinePlus

    ... are inside the scanner, the machine's x-ray beam rotates around you. (Modern "spiral" scanners can perform ... Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. ...

  3. Orbit CT scan

    MedlinePlus

    ... your provider if you take the diabetes medicine metformin (Glucophage) because you may need to take extra ... your provider if you take the diabetes medicine metformin (Glucophage) because you may need to take extra ...

  4. SU-E-I-91: Reproducibility in Prescribed Dose in AEC CT Scans Due to Table Height, Patient Size, and Localizer Acquisition Order

    SciTech Connect

    Winslow, J; Hurwitz, L; Christianson, O; Samei, E

    2014-06-01

    Purpose: In CT scanners, the automatic exposure control (AEC) tube current prescription depends on the acquired prescan localizer image(s). The purpose of this study was to quantify the effect that table height, patient size, and localizer acquisition order may have on the reproducibility in prescribed dose. Methods: Three phantoms were used for this study: the Mercury Phantom (comprises three tapered and four uniform regions of polyethylene 16, 23, 30, and 37 cm in diameter), acrylic sheets, and an adult anthropomorphic phantom. Phantoms were positioned per clinical protocol by our chief CT technologist or broader symmetry. Using a GE Discovery CT750HD scanner, a lateral (LAT) and posterior-anterior (PA) localizer was acquired for each phantom at different table heights. AEC scan acquisitions were prescribed for each combination of phantom, localizer orientation, and table height; the displayed volume CTDI was recorded for each. Results were analyzed versus table height. Results: For the two largest Mercury Phantom section scans based on the PA localizer, the percent change in volume CTDI from ideal were at least 20% lower and 35% greater for table heights 4 cm above and 4 cm below proper centering, respectively. For scans based on the LAT localizer, the percent change in volume CTDI from ideal were no greater than 12% different for 4 cm differences in table height. The properly centered PA and LAT localizer-based volume CTDI values were within 13% of each other. Conclusion: Since uncertainty in vertical patient positioning is inherently greater than lateral positioning and because the variability in dose exceeds any dose penalties incurred, the LAT localizer should be used to precisely and reproducibly deliver the intended amount of radiation prescribed by CT protocols. CT protocols can be adjusted to minimize the expected change in average patient dose.

  5. Comparative diagnostic values of grey-scale USS versus CT scan in the primary management of gynaecological pelvic mass with emphasis on ovarian cancer detection and staging.

    PubMed

    Onyeka, B A; Atalla, A; Deemer, H

    2001-09-01

    Thirty-one consecutive patients with clinical pelvic masses suspected to be gynaecological in origin were initially investigated by transabdominal grey-scale ultrasound (TAUS) and then by computed tomography (CT) prior to surgery and or chemotherapy. Retrospective comparative review of the reports of the two imaging methods was carried out on each patient and then correlated with surgical findings and histopathology report. The diagnostic potentials of the two imaging methods with respect to ovarian cancer detection and staging were particularly emphasised. The results were analysed and compared with published results of similar studies in the literature. Compared with TAUS we found CT scan more sensitive in making an overall presumptive diagnosis of pelvic mass (15/31, 48% vs. 9/31, 29%). The sensitivity of CT scan for all ovarian cancer detection was greater than that of TAUS (5/6, 83% vs. 4/6, 67%) but TAUS was more specific. The false negative and false positive values for cancer detection were comparable. Both methods were equally efficacious in detecting and staging advanced ovarian cancer cases (4/4, 100%). Visualisation of the ovaries occurred more readily with TAUS, which in addition offered a more precise assessment of ovarian tumour size. There were no significant differences in the two methods regarding tumour localisation (organ of origin), characterisation and the details of descriptive report when no presumptive diagnosis is offered. Overall CT did not offer significant additional features and did not result in changes in management plan in any of the patients reviewed. The marginal benefit of CT scan over TAUS will not warrant its routine usage in the diagnosis of gynaecological pelvic mass. Our findings largely reflected the conclusions of published reports in the literature. PMID:12521811

  6. Kilovoltage cone-beam CT: Comparative dose and image quality evaluations in partial and full-angle scan protocols

    SciTech Connect

    Kim, Sangroh; Yoo, Sua; Yin Fangfang; Samei, Ehsan; Yoshizumi, Terry

    2010-07-15

    Purpose: To assess imaging dose of partial and full-angle kilovoltage CBCT scan protocols and to evaluate image quality for each protocol. Methods: The authors obtained the CT dose index (CTDI) of the kilovoltage CBCT protocols in an on-board imager by ion chamber (IC) measurements and Monte Carlo (MC) simulations. A total of six new CBCT scan protocols were evaluated: Standard-dose head (100 kVp, 151 mA s, partial-angle), low-dose head (100 kVp, 75 mA s, partial-angle), high-quality head (100 kVp, 754 mA s, partial-angle), pelvis (125 kVp, 706 mA s, full-angle), pelvis spotlight (125 kVp, 752 mA s, partial-angle), and low-dose thorax (110 kVp, 271 mA s, full-angle). Using the point dose method, various CTDI values were calculated by (1) the conventional weighted CTDI (CTDI{sub w}) calculation and (2) Bakalyar's method (CTDI{sub wb}). The MC simulations were performed to obtain the CTDI{sub w} and CTDI{sub wb}, as well as from (3) central slice averaging (CTDI{sub 2D}) and (4) volume averaging (CTDI{sub 3D}) techniques. The CTDI values of the new protocols were compared to those of the old protocols (full-angle CBCT protocols). Image quality of the new protocols was evaluated following the CBCT image quality assurance (QA) protocol [S. Yoo et al., ''A quality assurance program for the on-board imager registered ,'' Med. Phys. 33(11), 4431-4447 (2006)] testing Hounsfield unit (HU) linearity, spatial linearity/resolution, contrast resolution, and HU uniformity. Results: The CTDI{sub w} were found as 6.0, 3.2, 29.0, 25.4, 23.8, and 7.7 mGy for the new protocols, respectively. The CTDI{sub w} and CTDI{sub wb} differed within +3% between IC measurements and MC simulations. Method (2) results were within {+-}12% of method (1). In MC simulations, the CTDI{sub w} and CTDI{sub wb} were comparable to the CTDI{sub 2D} and CTDI{sub 3D} with the differences ranging from -4.3% to 20.6%. The CTDI{sub 3D} were smallest among all the CTDI values. CTDI{sub w} of the new protocols

  7. The lingual lymph node identified as a sentinel node on CT lymphography in a patient with cN0 squamous cell carcinoma of the tongue

    PubMed Central

    Saito, M; Nishiyama, H; Oda, Y; Shingaki, S; Hayashi, T

    2012-01-01

    We performed CT lymphography on an 81-year-old female patient with a histologically confirmed squamous cell carcinoma of the tongue with no clinical or radiological evidence of cervical lymph node involvement. The lateral lingual lymph node was identified as a sentinel node, which is the first lymph node to receive drainage from a primary tumour. CT lymphography also showed draining lymphatics passing through the sublingual space, the medial side of the submandibular gland and near the hyoid bone and connected with the middle internal jugular node. Although metastasis to the lateral lingual lymph node is known as one of the crucial events in determining survival outcome in cancer of the tongue and floor of the mouth, very few reports are available on the imaging of the lateral lingual lymph node metastasis. This is the first report regarding the lateral lingual lymph node identified as a sentinel node demonstrated on CT lymphography. PMID:22074865

  8. Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion.

    PubMed

    Jackman, Timothy M; DelMonaco, Alex M; Morgan, Elise F

    2016-01-25

    Finite element (FE) models built from quantitative computed tomography (QCT) scans can provide patient-specific estimates of bone strength and fracture risk in the spine. While prior studies demonstrate accurate QCT-based FE predictions of vertebral stiffness and strength, the accuracy of the predicted failure patterns, i.e., the locations where failure occurs within the vertebra and the way in which the vertebra deforms as failure progresses, is less clear. This study used digital volume correlation (DVC) analyses of time-lapse micro-computed tomography (μCT) images acquired during mechanical testing (compression and anterior flexion) of thoracic spine segments (T7-T9, n=28) to measure displacements occurring throughout the T8 vertebral body at the ultimate point. These displacements were compared to those simulated by QCT-based FE analyses of T8. We hypothesized that the FE predictions would be more accurate when the boundary conditions are based on measurements of pressure distributions within intervertebral discs of similar level of disc degeneration vs. boundary conditions representing rigid platens. The FE simulations captured some of the general, qualitative features of the failure patterns; however, displacement errors ranged 12-279%. Contrary to our hypothesis, no differences in displacement errors were found when using boundary conditions representing measurements of disc pressure vs. rigid platens. The smallest displacement errors were obtained using boundary conditions that were measured directly by DVC at the T8 endplates. These findings indicate that further work is needed to develop methods of identifying physiological loading conditions for the vertebral body, for the purpose of achieving robust, patient-specific FE analyses of failure mechanisms.

  9. Abdominal and Pelvic CT

    MedlinePlus

    ... Professions Site Index A-Z Computed Tomography (CT) - Abdomen and Pelvis Computed tomography (CT) of the abdomen ... and Pelvis? What is CT Scanning of the Abdomen/Pelvis? Computed tomography, more commonly known as a ...

  10. Polysplenia Syndrome With Splenic and Skeletal Muscle Metastases From Thyroid Carcinoma Evaluated by FDG PET/CT: Case Report and Literature Review: A Care-Compliant Article.

    PubMed

    Li, Zu-Gui; Lin, Zhi-Chun; Mu, Hai-Yu

    2016-01-01

    Polysplenia syndrome (PSS) is a rare congenital abnormality. Metastases to spleen and skeletal muscle from differentiated thyroid cancer (DTC) are also extremely rare. Our case report aims to present an interesting case of PSS associated with splenic metastasis (SM) and skeletal muscle metastasis (SMM) from advanced papillary thyroid carcinoma which was evaluated on fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT). An 84-year-old Chinese man was admitted with the history of multiple enlarged masses in bilateral neck, right axillary, and inguinal areas for >2 months. The results of ultrasonography examination were highly suggestive of malignancy. The histological results of the following biopsy were consistent with papillary thyroid carcinoma with involvement of multiple regional lymph nodes. He was referred for an FDG PET/CT imaging to evaluate the situation. FDG PET/CT showed that an intense FDG-avid thyroid mass with widespread regional lymph node involvement and distant metastases in the body. Unexpected sites of metastases were detected in the spleens and skeletal muscles. Most interestingly, FDG PET/CT imaging also described the typical imaging findings of PSS including the 2 right-sided spleens, azygos and hemiazygos continuation of inferior vena cava (IVC), right-sided stomach, middle line liver, a short pancreas, preduodenal portal vein (PPV), and malrotation of gut. Whole body FDG PET/CT imaging can accurately evaluate the situation of DTC by detecting regional lymph node involvement, common and rare sites of distant metastases which are closely related to staging, management, and prognosis of this disease. Whole-body FDG PET/CT is also valuable in demonstrating the typical imaging features of PSS. PMID:26825891

  11. 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

  12. Validation of nonrigid registration in pretreatment and follow-up PET/CT scans for quantification of tumor residue in lung cancer patients.

    PubMed

    Spijkerman, Jolanda; Fontanarosa, Davide; Das, Marco; Van Elmpt, Wouter

    2014-01-01

    Nonrigid registrations of pre- and postradiotherapy (RT) PET/CT scans of NSCLC patients were performed with different algorithms and validated tracking internal landmarks. Dice overlap ratios (DR) of high FDG-uptake areas in registered PET/CT scans were then calculated to study patterns of relapse. For 22 patients, pre- and post-RT PET/CT scans were registered first rigidly and then nonrigidly. For three patients, two types (based on Demons or Morphons) of nonrigid registration algorithms each with four different parameter settings were applied and assessed using landmark validation. The two best performing methods were tested on all patients, who were then classified into three groups: large (Group 1), minor (Group2) or insufficient improvement (Group 3) of registration accuracy. For Group 1 and 2, DRs between high FDG-uptake areas in pre- and post-RT PET scans were determined. Distances between corresponding landmarks on deformed pre-RT and post-RT scans decreased for all registration methods. Differences between Demons and Morphons methods were smaller than 1 mm. For Group 1, landmark distance decreased from 9.5 ± 2.1 mm to 3.8 ± 1.2 mm (mean ± 1 SD, p < 0.001), and for Group 3 from 13.6 ± 3.2 mm to 8.0 ± 2.2 mm (p = 0.025). No significant change was observed for Group 2 where distances decreased from 5.6± 1.3 mm to 4.5 ± 1.1 mm (p = 0.093). DRs of high FDG-uptake areas improved significantly after nonrigid registration for most patients in Group 1. Landmark validation of nonrigid registration methods for follow-up CT imaging in NSCLC is necessary. Nonrigid registration significantly improves matching between pre- and post-RT CT scans for a subset of patients, although not in all patients. Hence, the quality of the registration needs to be assessed for each patient individually. Successful nonrigid registration increased the overlap between pre- and post-RT high FDG-uptake regions. PMID:25207414

  13. Association between Abdominal Fat (DXA) and Its Subcomponents (CT Scan) before and after Weight Loss in Obese Postmenopausal Women: A MONET Study.

    PubMed

    Doyon, Caroline Y; Brochu, Martin; Messier, Virginie; Lavoie, Marie-Ève; Faraj, May; Doucet, Eric; Rabasa-Lhoret, Rémi; Dionne, Isabelle J

    2011-01-01

    Introduction. Subcutaneous fat (ScF) and visceral fat (VF) measurements using CT scan are expensive and may imply significant radiation doses. Cross-sectional studies using CT scan showed that ScF and VF are significantly correlated with abdominal fat measured by DXA (AF-DXA). The association has not been studied after a weight loss. Objective. To determine (1) the associations between AF-DXA and ScF and VF before and after weight loss and (2) the associations between their changes. Methods. 137 overweight/obese postmenopausal women were divided in two groups (1-caloric restriction or 2-caloric restriction + resistance training). AF was assessed using DXA and CT scan. Results. Correlations between AF-DXA and ScF (before: r = 0.87, after; r = 0.87; P < .01) and, AF-DXA and VF (before: r = 0.61, after; r = 0.69; P < .01) are not different before and after the weight loss. Correlations between delta AF-DXA and delta ScF (r = 0.72; P < .01) or delta VF (r = 0.51; P < .01) were found. Conclusion. The use of AF-DXA as a surrogate for VF after weight loss is questionable, but may be interesting for ScF.

  14. Carcinoma of the larynx and hypopharynx: computed tomographic-histopathologic correlations

    SciTech Connect

    Silverman, P.M.; Bossen, E.H.; Fisher, S.R.; Cole, T.B.; Korobkin, M.; Halvorsen, R.A.

    1984-06-01

    Twenty consecutive patients underwent computed tomography (CT) prior to total laryngectomy in order to assess the accuracy of CT scanning in the evaluation of carcinoma of the larynx and hypopharynx. CT scans were prospectively interpreted and the extent of tumor was recorded graphically at five major levels of the larynx. The extent of tumor was similarly evaluated on whole-mount histologic sections of the laryngeal specimens prepared in the horizontal plane similar to the CT scans. The results were compared to assess the ability of CT to identify tumor extent accurately. Despite good correlation of gross tumor extent between histologic specimens and TC scanning, specific pitfalls in CT diagnosis were identified. Overestimation of tumor extent was caused by edematous changes in six patients and tumor-associated inflammatory changes in three patients. In seven patients, mass effect from adjacent bulky tumor significantly distorted normal structures, mimicking tumor involvement.

  15. Impact of morphine use in reducing the need for CT scan in patients with cervical spine trauma: a double blinded randomized clinical trial

    PubMed Central

    Sharifi, Mohammad Davood; Doloo, Hamid Zamani Moghadam; Hashemian, Amir Masoud; Tourghabe, Javad Tootian; Kakhki, Behrang Rezvani; Teimoori, Sasan Johari; Chokan, Niaz Mohammad Jafari; Noroozi, Hamid Reza

    2016-01-01

    Background Cervical spine trauma occurs mostly among young males due to falls and car accidents. The CT scan technology is replacing radiography in many medical clinics as it is very capable in detecting subtle cervical spine injuries. However, the use of CT scan for routine screening in patients with cervical spine trauma remains controversial due to its radiation risks and relatively high cost. Objective The focus of this research was on using morphine in patients with cervical spine trauma. The objective was to determine the ability of morphine to reduce the number of patients in need of CT scans. Methods This double-blinded randomized clinical trial study was conducted from April 2014 to March 2015 in Hasheminejad Hospital in Mashhad, Iran. We enrolled 67 patients with cervical spine trauma and normal radiography in the study. They were divided randomly into two groups (groups A and B), where group A received intravenous morphine, and group B received a placebo. We measured the pain scores in both groups before giving the medication and 10 minutes afterwards using a visual analog scale (VAS). Results As a result of receiving morphine, the patients in group A had significantly lower pain than group B (p-value < 0.001). The average pain score in group A was reduced by 43% versus 23% in group B. However, the most pain reduction was in those in group A with a normal CT scan. The pain score of these patients dropped by 52%. Conclusions The findings of this study suggest that patients with a normal radiography may be discharged with a cervical collar without a need for a CT scan if morphine reduces their pain. This is because the pain in these patients stem from the muscles and non-bony structures in the cervical spine area. Clinical trial registration: The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the IRCT ID: IRCT2013100214872N1 Funding The authors received no financial support for the research or for the publication

  16. Preoperative Evaluation of Renal Cell Carcinoma by Using 18F-FDG PET/CT

    PubMed Central

    Takahashi, Miwako; Kume, Haruki; Koyama, Keitaro; Nakagawa, Tohru; Fujimura, Tetsuya; Morikawa, Teppei; Fukayama, Masashi; Homma, Yukio; Ohtomo, Kuni; Momose, Toshimitsu

    2015-01-01

    Purpose This study aimed to characterize the FDG uptake of renal cell carcinoma (RCC) by the pathological subtype and nuclear grade. Patients and Methods We retrospectively identified patients who underwent 18F-FDG PET and subsequent partial or radical nephrectomy for renal tumors. The relationships of the SUV of renal tumor with subtypes, nuclear grade, and clinicopathological variables were investigated. Results Ninety-two tumors were analyzed, including 52 low-grade (G1 and G2) and 18 high-grade (G3 and G4) clear cell RCC; 7 chromophobe, 5 papillary, and 1 unclassified RCC; and 9 benign tumors (7 angiomyolipoma and 2 oncocytoma). The SUVs of high-grade clear cell RCC (mean ± SD, 6.8 ± 5.1) and papillary RCC (6.6 ± 3.7) were significantly higher than that of the controls (2.2 ± 0.3). The SUV of high-grade clear cell RCC was higher than that of low-grade tumors (median, 4.0 vs. 2.2; P < 0.001). The optimal SUV cutoff value of 3.0 helped to differentiate high-grade from low-grade clear cell RCC, with 89% sensitivity and 87% specificity. On multiple regression analysis, a high grade was the most significant predictor of SUV for clear cell RCC. Conclusions FDG uptake higher than that observed in normal kidney tissues suggests a high-grade clear cell RCC or papillary RCC subtype. FDG-PET using SUV may have a role in prediction of pathological grade of renal tumor. PMID:26164183

  17. Gold Nanorods Based Air Scanning Electron Microscopy and Diffusion Reflection Imaging for Mapping Tumor Margins in Squamous Cell Carcinoma.

    PubMed

    Ankri, Rinat; Ashkenazy, Ariel; Milstein, Yonat; Brami, Yaniv; Olshinka, Asaf; Goldenberg-Cohen, Nitza; Popovtzer, Aron; Fixler, Dror; Hirshberg, Abraham

    2016-02-23

    A critical challenge arising during a surgical procedure for tumor removal is the determination of tumor margins. Gold nanorods (GNRs) conjugated to epidermal growth factor receptors (EGFR) (GNRs-EGFR) have long been used in the detection of cancerous cells as the expression of EGFR dramatically increases once the tissue becomes cancerous. Optical techniques for the identification of these GNRs-EGFR in tumor are intensively developed based on the unique scattering and absorption properties of the GNRs. In this study, we investigate the distribution of the GNRs in tissue sections presenting squamous cell carcinoma (SCC) to evaluate the SCC margins. Air scanning electron microscopy (airSEM), a novel, high resolution microscopy is used, enabling to localize and actually visualize nanoparticles on the tissue. The airSEM pictures presented a gradient of GNRs from the tumor to normal epithelium, spread in an area of 1 mm, suggesting tumor margins of 1 mm. Diffusion reflection (DR) measurements, performed in a resolution of 1 mm, of human oral SCC have shown a clear difference between the DR profiles of the healthy epithelium and the tumor itself. PMID:26759920

  18. In vitro analysis of the cement mantle of femoral hip implants: development and validation of a CT-scan based measurement tool.

    PubMed

    Scheerlinck, Thierry; de Mey, Johan; Deklerck, Rudi

    2005-07-01

    We developed, validated and assessed inter- and intraobserver reliability of a CT-scan based measurement tool to evaluate morphological characteristics of the bone-cement-stem complex of hip implants in cadaver femurs. Two different models were investigated: the stem-cavity model using a double tapered polished femoral-stem that is removed after cement curing and the plastic-replica model using a stereolithographic stem replica that is left in place during CT-scanning. Software was developed to segment and analyze connective CT-images and identify the contours of bone, cement, and stem based on their respective gray values. Volume parameters (whole specimen, cement, stem, air contents of bone and cement), concentricity parameters (distances between centroids of stem and cement, cement and bone, stem and bone), contact surfaces (bone/air and cement/bone) and bone cement mantle thickness parameters were calculated. A three-dimensional protocol was developed to evaluate the minimal mantle thickness out of the CT-plane. The average accuracy for surfaces within CT-images was 7.47 mm2 (1.80%), for bone and cement mantle thickness it was 0.51 mm (9.39%), for distances between centroids it was 0.38 mm (18.5%) and contours: 0.27 mm (2.57%). The intra- and interobserver reliability of air content in bone and cement was sub-optimal (intraclass-correlation coefficient (ICC) as low as 0.54 with an average ICC of 0.85). All other variables were reliable (ICC>0.81, average ICC: 0.96). This in vitro technique can assess characteristics of cement mantles produced by different cementing techniques, stem types or centralizers.

  19. Image-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    NASA Astrophysics Data System (ADS)

    Unberath, Mathias; Choi, Jang-Hwan; Berger, Martin; Maier, Andreas; Fahrig, Rebecca

    2015-03-01

    We previously introduced four fiducial marker-based strategies to compensate for involuntary knee-joint motion during weight-bearing C-arm CT scanning of the lower body. 2D methods showed significant reduction of motion- related artifacts, but 3D methods worked best. However, previous methods led to increased examination times and patient discomfort caused by the marker attachment process. Moreover, sub-optimal marker placement may lead to decreased marker detectability and therefore unstable motion estimates. In order to reduce overall patient discomfort, we developed a new image-based 2D projection shifting method. A C-arm cone-beam CT system was used to acquire projection images of five healthy volunteers at various flexion angles. Projection matrices for the horizontal scanning trajectory were calibrated using the Siemens standard PDS-2 phantom. The initial reconstruction was forward projected using maximum-intensity projections (MIP), yielding an estimate of a static scan. This estimate was then used to obtain the 2D projection shifts via registration. For the scan with the most motion, the proposed method reproduced the marker-based results with a mean error of 2.90 mm +/- 1.43 mm (compared to a mean error of 4.10 mm +/- 3.03 mm in the uncorrected case). Bone contour surrounding modeling clay layer was improved. The proposed method is a first step towards automatic image-based, marker-free motion-compensation.

  20. CT-Guided Radiofrequency Ablation of T1a Renal Cell Carcinoma in Korea: Mid-Term Outcomes

    PubMed Central

    Kim, Hae Jin; Park, Jung Jae; Kim, Chan Kyo

    2016-01-01

    Objective To evaluate the mid-term outcomes of percutaneous radiofrequency ablation (RFA) treatment in patients with small (< 4 cm) renal cell carcinoma (RCC) in Korea. Materials and Methods Between 2010 and 2015, 51 patients (40 men and 11 women; median age, 57 years) with biopsyproven 51 RCC were treated using CT-guided RFA. All patients were clinically staged T1aN0M0 prior to RFA. The median tumor size and follow-up period were 2.1 cm (range, 1.0–3.9 cm) and 26 months (4–60 months), respectively. Local tumor progression, distant metastasis, primary and secondary effectiveness rates, and major complication rates were recorded. Estimated glomerular filtration rates (GFRs) between pre-RFA and last follow-up were compared using paired t tests. The 2-year recurrence-free survival rate was calculated using Kaplan-Meier survival analysis. Results Of the 51 patients, 2 (3.9%) experienced local tumor progression, and 1 (2.0%) had lymph node metastasis after the first RFA session. Primary and secondary effectiveness rates were 96.1% (49/51) and 100% (1/1), respectively. Only 1 patient experienced a major complication (uretero-pelvic stricture) after the second RFA session for treating a local tumor progression, and the major complication rate was 1.9% (1/52). The median pre-RFA and last follow-up GFRs were 87.1 mL/ min/1.73 m2 (14.2–142.7 mL/min/1.73 m2) and 72.0 mL/min/1.73 m2 (7.2–112.6 mL/min/1.73 m2), respectively (p < 0.0001). The 2-year recurrence-free survival rate was 96.0%. Conclusion CT-guided RFA is a safe and effective treatment in Korean patients with T1a RCC because of excellent mid-term outcomes. PMID:27587966

  1. Chronic vegetative state after severe head injury: clinical study; electrophysiological investigations and CT scan in 15 cases.

    PubMed

    Danze, F; Brule, J F; Haddad, K

    1989-01-01

    Fifteen cases of chronic vegetative state (CVS), following severe head injury and lasting for two years or more, are reported. Vegetative state, in most instances after a period of coma, consists of a return of wakefulness accompanied by an apparent total lack of higher mental activity. A protracted period of vegetative state has been chosen to ensure that the possibility of further recovery could virtually be excluded. The term of CVS could therefore be reasonably used to designate these cases. Moreover, cerebral lesions were then thought to be the same as in neuropathological studies. Severe head injury, responsible for CVS, initially affected adults in 11 cases and children in four cases. The range of duration of the vegetative state was 2 to 14 years, with a mean of five years. The data of clinical study and electrophysiological investigations (EEG, brain stem auditory evoked potentials, somatosensory evoked potentials) are reported. A CT scan was carried out in each case to study the impairment of cerebral hemispheres and brain stem, with particular attention to the ventricular size. The results confirm that in the CVS, lesions affect mainly the hemispheres, while brain stem functions are mainly preserved. Vegetative State (VS) is the term proposed by Jennett and Plum (1972) to describe the condition that sometimes emerges after a period of coma, after a severe head injury (SHI). This condition consists of a return of wakefulness accompanied by an apparent total lack of higher mental activity. A practical definition of this state characterised by wakefulness without responsiveness is that the eyes open spontaneously and/or in response to verbal stimuli. Sleep-wake cycles exist. The patients can neither obey simple orders nor locate painful stimuli. They utter no comprehensible words. Blood pressure and breathing remain steady. It is much more difficult to specify exactly how long such a state must persist before it can be confidently declared permanent

  2. Computer-aided diagnosis of pulmonary nodules on CT scans: Segmentation and classification using 3D active contours

    PubMed Central

    Way, Ted W.; Hadjiiski, Lubomir M.; Sahiner, Berkman; Chan, Heang-Ping; Cascade, Philip N.; Kazerooni, Ella A.; Bogot, Naama; Zhou, Chuan

    2009-01-01

    We are developing a computer-aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three-dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two-dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface, (2) 3D curvature, which imposes a smoothness constraint in the z direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray-level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run-length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave-one-case-out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve (Az) of 0.83±0.04. Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D AC

  3. A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation

    SciTech Connect

    Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos; Schmidt, Taly Gilat

    2012-09-15

    Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360 Degree-Sign through anthropomorphic voxelized female chest and head (0 Degree-Sign and 30 Degree-Sign tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI{sub vol} and multiplying by a physical CTDI{sub vol} measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30 Degree-Sign relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate

  4. Evaluation of the dependence of the exposure dose on the attenuation correction in brain PET/CT scans using 18F-FDG

    NASA Astrophysics Data System (ADS)

    Choi, Eun-Jin; Jeong, Moon-Taeg; Jang, Seong-Joo; Choi, Nam-Gil; Han, Jae-Bok; Yang, Nam-Hee; Dong, Kyung-Rae; Chung, Woon-Kwan; Lee, Yun-Jong; Ryu, Young-Hwan; Choi, Sung-Hyun; Seong, Kyeong-Jeong

    2014-01-01

    This study examined whether scanning could be performed with minimum dose and minimum exposure to the patient after an attenuation correction. A Hoffman 3D Brain Phantom was used in BIO_40 and D_690 PET/CT scanners, and the CT dose for the equipment was classified as a low dose (minimum dose), medium dose (general dose for scanning) and high dose (dose with use of contrast medium) before obtaining the image at a fixed kilo-voltage-peak (kVp) and milliam