Synthetic techniques of radiopharmaceuticals production labeled with C-11 for PET in cardiology

NASA Astrophysics Data System (ADS)

Dyubkov, V. S.; Ekaeva, I. V.; Katunina, T. A.; Rumyantsev, A. S.; Silchenkov, A. V.; Tuflina, T. V.

2017-01-01

Positron emission tomography (PET) and PET-Computerised Tomography (CT) are unique, non-invasive diagnostic techniques, in which the local, temporal and quantitative distributions of radioactive labelled substances are measured to investigate physiological processes. It is well known that PET centre of Bakulev Scientific Centre for Cardiovascular Surgery is the oldest one in Moscow. During more than fifteen years a large number of patients have received PET scans. Due to main stream of Scientific Centre, emphasis is placed on examining the heart functioning. For the diagnosis innervation of the heart muscle a number of radiopharmaceuticals are used, including PET radiopharmaceuticals such as 11C-CGP 12177, 11C-meta-hydroxyephedrine as well as its synthetic analogues labelled with other PET radionuclides (18F, 68Ga). 11C-meta-hydroxyephedrine is one of the most perspective radiopharmaceutical for an investigation of cardiac receptors function due to required materials availability for a radio synthesis in Russia. The main advantage of proposed 11C-meta-hydroxyephedrine synthesis technique is the use of a catalyst which allows one decrease reaction time from 5 minutes to 30 seconds. Obtained results allow one decrease reaction time of methylation and increase radiochemical and technological yields.

Mucosal Cysts of the Maxillary Sinus in Solid Organ Transplant Population: Computerised Tomography Follow-Up Results

PubMed Central

Aydın, Erdinç; Yerli, Hasan; Tanrıkulu, Suna; Hizal, Evren

2013-01-01

Background: The clinical significance of maxillary sinus mucosal cysts in liver and kidney transplant recipients remains unclear. Aim: To investigate the course of maxillary mucosal cysts in liver and kidney transplantation patients. Study Design: Retrospective clinical study Methods: Paranasal sinus computed tomography scans of 169 renal and 43 hepatic transplant recipients were reviewed. The incidence, size and growth characteristics of maxillary mucosal cysts in the renal and hepatic transplant population were noted. Results: Overall incidence of maxillary sinus mucosal cyst in transplantation patients was found to be 24.5%, with a male to female ratio of 2:1 (p<0.05). Follow-up views of 26 patients showed that the size of the cysts increased in 19, decreased in 4, and remained the same in 3 patients. Mean growth rate of the cysts was calculated to be 6.30 ± 7.02 mm2 per month. Most of the cysts were located on the inferior wall of the maxillary sinus. Conclusion: Incidence of the maxillary mucosal cysts in renal and hepatic transplant recipients does not differ from general population, but these cysts have a greater tendency to grow. Specific measures are not needed for isolated, asymptomatic maxillary mucosal cysts in transplant populations. PMID:25207125

3D printing the pterygopalatine fossa: a negative space model of a complex structure.

PubMed

Bannon, Ross; Parihar, Shivani; Skarparis, Yiannis; Varsou, Ourania; Cezayirli, Enis

2018-02-01

The pterygopalatine fossa is one of the most complex anatomical regions to understand. It is poorly visualized in cadaveric dissection and most textbooks rely on schematic depictions. We describe our approach to creating a low-cost, 3D model of the pterygopalatine fossa, including its associated canals and foramina, using an affordable "desktop" 3D printer. We used open source software to create a volume render of the pterygopalatine fossa from axial slices of a head computerised tomography scan. These data were then exported to a 3D printer to produce an anatomically accurate model. The resulting 'negative space' model of the pterygopalatine fossa provides a useful and innovative aid for understanding the complex anatomical relationships of the pterygopalatine fossa. This model was designed primarily for medical students; however, it will also be of interest to postgraduates in ENT, ophthalmology, neurosurgery, and radiology. The technical process described may be replicated by other departments wishing to develop their own anatomical models whilst incurring minimal costs.

A randomised controlled trial of oral chloral hydrate vs. intranasal dexmedetomidine before computerised tomography in children.

PubMed

Yuen, V M; Li, B L; Cheuk, D K; Leung, M K M; Hui, T W C; Wong, I C; Lam, W W; Choi, S W; Irwin, M G

2017-10-01

Chloral hydrate is commonly used to sedate children for painless procedures. Children may recover more quickly after sedation with dexmedetomidine, which has a shorter half-life. We randomly allocated 196 children to chloral hydrate syrup 50 mg.kg -1 and intranasal saline spray, or placebo syrup and intranasal dexmedetomidine spray 3 μg.kg -1 , 30 min before computerised tomography studies. More children resisted or cried after drinking chloral hydrate syrup than placebo syrup, 72 of 107 (67%) vs. 42 of 87 (48%), p = 0.009, but there was no difference after intranasal saline vs. dexmedetomidine, 49 of 107 (46%) vs. 40 of 87 (46%), p = 0.98. Sedation was satisfactory in 81 of 107 (76%) children after chloral hydrate and 64 of 87 (74%) children after dexmedetomidine, p = 0.74. Of the 173 children followed up for at least 4 h after discharge, 38 of 97 (39%) had recovered normal function after chloral hydrate and 32 of 76 (42%) after dexmedetomidine, p = 0.76. Six children vomited after chloral hydrate syrup and placebo spray vs. none after placebo syrup and dexmedetomidine spray, p = 0.03. © 2017 The Association of Anaesthetists of Great Britain and Ireland.

Automatic 2D and 3D segmentation of liver from Computerised Tomography

NASA Astrophysics Data System (ADS)

Evans, Alun

As part of the diagnosis of liver disease, a Computerised Tomography (CT) scan is taken of the patient, which the clinician then uses for assistance in determining the presence and extent of the disease. This thesis presents the background, methodology, results and future work of a project that employs automated methods to segment liver tissue. The clinical motivation behind this work is the desire to facilitate the diagnosis of liver disease such as cirrhosis or cancer, assist in volume determination for liver transplantation, and possibly assist in measuring the effect of any treatment given to the liver. Previous attempts at automatic segmentation of liver tissue have relied on 2D, low-level segmentation techniques, such as thresholding and mathematical morphology, to obtain the basic liver structure. The derived boundary can then be smoothed or refined using more advanced methods. The 2D results presented in this thesis improve greatly on this previous work by using a topology adaptive active contour model to accurately segment liver tissue from CT images. The use of conventional snakes for liver segmentation is difficult due to the presence of other organs closely surrounding the liver this new technique avoids this problem by adding an inflationary force to the basic snake equation, and initialising the snake inside the liver. The concepts underlying the 2D technique are extended to 3D, and results of full 3D segmentation of the liver are presented. The 3D technique makes use of an inflationary active surface model which is adaptively reparameterised, according to its size and local curvature, in order that it may more accurately segment the organ. Statistical analysis of the accuracy of the segmentation is presented for 18 healthy liver datasets, and results of the segmentation of unhealthy livers are also shown. The novel work developed during the course of this project has possibilities for use in other areas of medical imaging research, for example the segmentation of internal liver structures, and the segmentation and classification of unhealthy tissue. The possibilities of this future work are discussed towards the end of the report.

Micro-CT based modelling for characterising injection-moulded porous titanium implants.

PubMed

Chen, Junning; Chen, Liangjian; Chang, Che-Cheng; Zhang, Zhongpu; Li, Wei; Swain, Michael V; Li, Qing

2017-01-01

Design of prosthetic implants to ensure rapid and stable osseointegration remains a significant challenge, and continuous efforts have been directed to new implant materials, structures and morphology. This paper aims to develop and characterise a porous titanium dental implant fabricated by metallic powder injection-moulding. The surface morphology of the specimens was first examined with a scanning electron microscope (SEM), followed by microscopic computerised tomography (μ-CT) scanning to capture its 3D microscopic features non-destructively. The nature of porosity and pore sizes were determined statistically. A homogenisation technique based on the Hills-energy theorem was adopted to evaluate its directional elastic moduli, and the conservation of mass theorem was employed to quantify the oxygen diffusivity for bio-transportation feature. This porous medium was found to have pore sizes varying from 50 to 400 µm and the average porosity of 46.90 ± 1.83%. The anisotropic principal elastic moduli were found fairly close to the upper range of cortical bone, and the directional diffusivities could potentially enable radial osseous tissue ingrowth and vascularisation. This porous titanium successfully reduces the elastic modulus mismatch between implant and bone for dental and orthopaedic applications, and provides improved capacity for transporting oxygen, nutrient and waste for pre-vascular network formation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Computerised Axial Tomography (CAT)

DTIC Science & Technology

1990-06-01

commercial market. EMI, which had originally counted on being the only firm selling CT units , subsequently increased its production in order to overtake...to a rough estimate’"’ the number of CT scanners at present working in Italy is about 18 units installed. apart from those in the large cities such as...hGdcl scanners and 198 total body scanners): among othar things, they emphasise that a CT unit , works, on an average, for 5.4 days in the week and

Computerised tomography vs magnetic resonance imaging for modeling of patient-specific instrumentation in total knee arthroplasty.

PubMed

Stirling, Paul; Valsalan Mannambeth, Rejith; Soler, Agustin; Batta, Vineet; Malhotra, Rajeev Kumar; Kalairajah, Yegappan

2015-03-18

To summarise and compare currently available evidence regarding accuracy of pre-operative imaging, which is one of the key choices for surgeons contemplating patient-specific instrumentation (PSI) surgery. The MEDLINE and EMBASE medical literature databases were searched, from January 1990 to December 2013, to identify relevant studies. The data from several clinical studies was assimilated to allow appreciation and comparison of the accuracy of each modality. The overall accuracy of each modality was calculated as proportion of outliers > 3% in the coronal plane of both computerised tomography (CT) or magnetic resonance imaging (MRI). Seven clinical studies matched our inclusion criteria for comparison and were included in our study for statistical analysis. Three of these reported series using MRI and four with CT. Overall percentage of outliers > 3% in patients with CT-based PSI systems was 12.5% vs 16.9% for MRI-based systems. These results were not statistically significant. Although many studies have been undertaken to determine the ideal pre-operative imaging modality, conclusions remain speculative in the absence of long term data. Ultimately, information regarding accuracy of CT and MRI will be the main determining factor. Increased accuracy of pre-operative imaging could result in longer-term savings, and reduced accumulated dose of radiation by eliminating the need for post-operative imaging and revision surgery.

Computerised tomography vs magnetic resonance imaging for modeling of patient-specific instrumentation in total knee arthroplasty

PubMed Central

Stirling, Paul; Valsalan Mannambeth, Rejith; Soler, Agustin; Batta, Vineet; Malhotra, Rajeev Kumar; Kalairajah, Yegappan

2015-01-01

AIM: To summarise and compare currently available evidence regarding accuracy of pre-operative imaging, which is one of the key choices for surgeons contemplating patient-specific instrumentation (PSI) surgery. METHODS: The MEDLINE and EMBASE medical literature databases were searched, from January 1990 to December 2013, to identify relevant studies. The data from several clinical studies was assimilated to allow appreciation and comparison of the accuracy of each modality. The overall accuracy of each modality was calculated as proportion of outliers > 3% in the coronal plane of both computerised tomography (CT) or magnetic resonance imaging (MRI). RESULTS: Seven clinical studies matched our inclusion criteria for comparison and were included in our study for statistical analysis. Three of these reported series using MRI and four with CT. Overall percentage of outliers > 3% in patients with CT-based PSI systems was 12.5% vs 16.9% for MRI-based systems. These results were not statistically significant. CONCLUSION: Although many studies have been undertaken to determine the ideal pre-operative imaging modality, conclusions remain speculative in the absence of long term data. Ultimately, information regarding accuracy of CT and MRI will be the main determining factor. Increased accuracy of pre-operative imaging could result in longer-term savings, and reduced accumulated dose of radiation by eliminating the need for post-operative imaging and revision surgery. PMID:25793170

Clinics in diagnostic imaging (7). Omental caking due to ovarian carcinoma.

PubMed

Helpert, C; Peh, W C; Ng, T Y

1995-12-01

A 52-year-old Chinese woman with previously resected ovarian carcinoma was found to have ascites and a mass in the Pouch of Douglas on follow-up examination. A large omental cake was detected on computerised tomography (CT), and subsequently confirmed during laparotomy. After completion of four cycles of chemotherapy, a near complete resolution of omental metastases was demonstrated on both CT and laparotomy. The role of CT in ovarian cancer is discussed and the CT appearances of omental tumour are described.

Blood-brain barrier dysfunction following traumatic brain injury: correlation of K(trans) (DCE-MRI) and SUVR (99mTc-DTPA SPECT) but not serum S100B.

PubMed

Winter, Craig; Bell, Christopher; Whyte, Timothy; Cardinal, John; Macfarlane, David; Rose, Stephen

2015-07-01

Damage to the blood-brain barrier (BBB) is an important secondary mechanism that occurs following traumatic brain injury (TBI) and may provide a potential therapeutic target to improve patient outcome. For such a progress to be realised, an accurate assessment of BBB compromise needs to be established. Fourteen patients with TBI were prospectively recruited. Post-traumatic BBB dysfunction was assessed using dynamic contrast-enhanced MRI (DCE-MRI), single-photon emission computerised tomography (SPECT) and serum S100B levels. A statistically significant correlation between standardised uptake value ratio (SUVR) calculated from 99mTc-DTPA SPECT and K(trans) (a volume transfer constant) from DCE-MRI was found for those eight patients who had concurrent scans. The positive correlation persisted when the data were corrected for patient age, number of days following trauma and both parameters combined. We found no statistically significant correlation between either of the imaging modalities and concurrent serum S100B levels. The correlation of SPECT with DCE-MRI suggests that either scan may be used to assess post-traumatic BBB damage. We could not support serum S100B to be an accurate measure of BBB damage when sampled a number of days following injury but the small number of patients, the heterogeneity in TBI patients and the delay following injury makes any firm conclusions regarding S100B and BBB difficult.

[Cryptogenic stroke in a young patient with heart disease and kidney failure].

PubMed

Oyanguren, B; Segoviano, R; Alegria, E; Besada, E; Gonzalez-Salaices, M; Eimil-Ortiz, M; Lopez de Silanes, C

2017-05-16

Fabry's disease is an infrequent metabolic pathology linked to the X chromosome which causes a wide variety of signs and symptoms. A 39-year-old male who was admitted to our stroke unit with right-side hemiparesis (1 + 0) and dysarthria (1). The score on the National Institute of Health Stroke Scale was 2. The patient presented angiokeratomas in both thighs. A computerised axial tomography scan of the head showed left thalamic acute infarction. The duplex scan of the supra-aortic trunks was normal, and the transcranial Doppler reflected a generalised increase in the pulsatility indices. Transthoracic echocardiography showed left ventricular hypertrophy and left atrial dilatation. He was discharged five days later, with antiaggregating medication but asymptomatic. The prolonged Holter-electrocardiogram recording showed paroxysmal atrial fibrillation. One notable value in the urine analysis was microalbuminuria of 281 mg/L. In view of the multi-organic involvement and the family history, a study for Fabry's disease was performed. Activity of the enzyme alpha-galactosidase A was diminished, and the presence of a mutation in the GLA gene was found. The patient's brother, who suffered from kidney failure and atrial fibrillation, was positive for this mutation. The patient is on treatment with agalsidase beta. Fabry's disease must be suspected in young males with heart disease, stroke or peripheral neuropathy, skin lesions, kidney failure and a history of cases in the family. Hormone replacement therapy must be established at an early stage, as it can improve the prognosis.

Stereolithographic Surgical Template: A Review

PubMed Central

Dandekeri, Shilpa Sudesh; Sowmya, M.K.; Bhandary, Shruthi

2013-01-01

Implant placement has become a routine modality of dental care.Improvements in surgical reconstructive methods as well as increased prosthetic demands,require a highly accurate diagnosis, planning and placement. Recently,computer-aided design and manufacturing have made it possible to use data from computerised tomography to not only plan implant rehabilitation,but also transfer this information to the surgery.A review on one of this technique called Stereolithography is presented in this article.It permits graphic and complex 3D implant placement and fabrication of stereolithographic surgical templates. Also offers many significant benefits over traditional procedures. PMID:24179955

Evaluating the risk of appendiceal perforation when using ultrasound as the initial diagnostic imaging modality in children with suspected appendicitis.

PubMed

Alerhand, Stephen; Meltzer, James; Tay, Ee Tein

2017-08-01

Ultrasound scan has gained attention for diagnosing appendicitis due to its avoidance of ionizing radiation. However, studies show that ultrasound scan carries inferior sensitivity to computed tomography scan. A non-diagnostic ultrasound scan could increase the time to diagnosis and appendicectomy, particularly if follow-up computed tomography scan is needed. Some studies suggest that delaying appendicectomy increases the risk of perforation. To investigate the risk of appendiceal perforation when using ultrasound scan as the initial diagnostic imaging modality in children with suspected appendicitis. We retrospectively reviewed 1411 charts of children ≤17 years old diagnosed with appendicitis at two urban academic medical centers. Patients who underwent ultrasound scan first were compared to those who underwent computed tomography scan first. In the sub-group analysis, patients who only received ultrasound scan were compared to those who received initial ultrasound scan followed by computed tomography scan. Main outcome measures were appendiceal perforation rate and time from triage to appendicectomy. In 720 children eligible for analysis, there was no significant difference in perforation rate between those who had initial ultrasound scan and those who had initial computed tomography scan (7.3% vs. 8.9%, p = 0.44), nor in those who had ultrasound scan only and those who had initial ultrasound scan followed by computed tomography scan (8.0% vs. 5.6%, p = 0.42). Those patients who had ultrasound scan first had a shorter triage-to-incision time than those who had computed tomography scan first (9.2 (IQR: 5.9, 14.0) vs. 10.2 (IQR: 7.3, 14.3) hours, p = 0.03), whereas those who had ultrasound scan followed by computed tomography scan took longer than those who had ultrasound scan only (7.8 (IQR: 5.3, 11.6) vs. 15.1 (IQR: 10.6, 20.6), p < 0.001). Children < 12 years old receiving ultrasound scan first had lower perforation rate (p = 0.01) and shorter triage-to-incision time (p = 0.003). Children with suspected appendicitis receiving ultrasound scan as the initial diagnostic imaging modality do not have increased risk of perforation compared to those receiving computed tomography scan first. We recommend that children <12 years of age receive ultrasound scan first.

Leg CT scan

MedlinePlus

CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... CT scan makes detailed pictures of the body very quickly. The test may help look for: An abscess ...

Arm CT scan

MedlinePlus

CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Healing problems or scar tissue following surgery A CT scan may also be used to guide a surgeon ...

Pelvic CT scan

MedlinePlus

CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye CT scans do expose you to more radiation ...

Shoulder CT scan

MedlinePlus

CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye Birth defect if done during pregnancy CT scans ...

Body CT (CAT Scan)

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses ... of CT Scanning of the Body? What is CT Scanning of the Body? Computed tomography, more commonly ...

Sinus CT scan

MedlinePlus

CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... Risks for a CT scan includes: Being exposed to radiation Allergic reaction to contrast dye CT scans expose you to more radiation than regular ...

Computed Tomography (CT) - Spine

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Spine Computed tomography (CT) of the spine is ... of CT Scanning of the Spine? What is CT Scanning of the Spine? Computed tomography, more commonly ...

Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

PubMed

Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

2013-11-01

To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p < 0.0001) and ultrasound pachymetry (p = < .0001). Ultrasound pachymetry readings had better 95% limits of agreement with swept source optical coherence tomography than slit scanning topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p < 0.05 for all). Overall, reproducibility coefficients and intraclass correlation coefficients were significantly better with swept source optical coherence tomography for measurement of central corneal thickness, anterior best-fit sphere and, posterior best-fit sphere (all p < 0.001). Corneal thickness and elevation measurements were significantly different between swept source optical coherence tomography and slit scanning topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Lumbar spine CT scan

MedlinePlus

CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... CT scans rapidly makes detailed pictures of the lower back. The test may be used to look for: ...

Recurrent intestinal volvulus in midgut malrotation causing acute bowel obstruction: A case report

PubMed Central

Sheikh, Fayed; Balarajah, Vickna; Ayantunde, Abraham Abiodun

2013-01-01

Intestinal malrotation occurs when there is a disruption in the normal embryological development of the bowel. The majority of patients present with clinical features in childhood, though rarely a first presentation can take place in adulthood. Recurrent bowel obstruction in patients with previous abdominal operation for midgut malrotation is mostly due to adhesions but very few reported cases have been due to recurrent volvulus. We present the case of a 22-year-old gentleman who had laparotomy in childhood for small bowel volvulus and then presented with acute bowel obstruction. Preoperative computerised tomography scan showed small bowel obstruction and features in keeping with midgut malrotation. Emergency laparotomy findings confirmed midgut malrotation with absent appendix, abnormal location of caecum, ascending colon and small bowel. In addition, there were small bowel volvulus and a segment of terminal ileal stricture. Limited right hemicolectomy was performed with excellent postoperative recovery. This case is presented to illustrate a rare occurrence and raise an awareness of the possibility of dreadful recurrent volvulus even several years following an initial Ladd’s procedure for midgut malrotation. Therefore, one will need to exercise a high index of suspicion and this becomes very crucial in order to ensure prompt surgical intervention and thereby preventing an attendant bowel ischaemia with its associated high fatality. PMID:23556060

Recurrent intestinal volvulus in midgut malrotation causing acute bowel obstruction: A case report.

PubMed

Sheikh, Fayed; Balarajah, Vickna; Ayantunde, Abraham Abiodun

2013-03-27

Intestinal malrotation occurs when there is a disruption in the normal embryological development of the bowel. The majority of patients present with clinical features in childhood, though rarely a first presentation can take place in adulthood. Recurrent bowel obstruction in patients with previous abdominal operation for midgut malrotation is mostly due to adhesions but very few reported cases have been due to recurrent volvulus. We present the case of a 22-year-old gentleman who had laparotomy in childhood for small bowel volvulus and then presented with acute bowel obstruction. Preoperative computerised tomography scan showed small bowel obstruction and features in keeping with midgut malrotation. Emergency laparotomy findings confirmed midgut malrotation with absent appendix, abnormal location of caecum, ascending colon and small bowel. In addition, there were small bowel volvulus and a segment of terminal ileal stricture. Limited right hemicolectomy was performed with excellent postoperative recovery. This case is presented to illustrate a rare occurrence and raise an awareness of the possibility of dreadful recurrent volvulus even several years following an initial Ladd's procedure for midgut malrotation. Therefore, one will need to exercise a high index of suspicion and this becomes very crucial in order to ensure prompt surgical intervention and thereby preventing an attendant bowel ischaemia with its associated high fatality.

Use of the 3D surgical modelling technique with open-source software for mandibular fibula free flap reconstruction and its surgical guides.

PubMed

Ganry, L; Hersant, B; Quilichini, J; Leyder, P; Meningaud, J P

2017-06-01

Tridimensional (3D) surgical modelling is a necessary step to create 3D-printed surgical tools, and expensive professional software is generally needed. Open-source software are functional, reliable, updated, may be downloaded for free and used to produce 3D models. Few surgical teams have used free solutions for mastering 3D surgical modelling for reconstructive surgery with osseous free flaps. We described an Open-source software 3D surgical modelling protocol to perform a fast and nearly free mandibular reconstruction with microvascular fibula free flap and its surgical guides, with no need for engineering support. Four successive specialised Open-source software were used to perform our 3D modelling: OsiriX ® , Meshlab ® , Netfabb ® and Blender ® . Digital Imaging and Communications in Medicine (DICOM) data on patient skull and fibula, obtained with a computerised tomography (CT) scan, were needed. The 3D modelling of the reconstructed mandible and its surgical guides were created. This new strategy may improve surgical management in Oral and Craniomaxillofacial surgery. Further clinical studies are needed to demonstrate the feasibility, reproducibility, transfer of know how and benefits of this technique. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Recurrent ventricular arrhythmias complicating myocardial infarction in the presence of phaeochromocytoma.

PubMed Central

McNeill, A J; Adgey, A A; Wilson, C

1992-01-01

After an acute myocardial infarction a 49 year old man developed late recurrent severe ventricular arrhythmias coincident with transient hypertensive episodes. A phaeochromocytoma was diagnosed on the basis of the urinary concentration of catecholamines and computerised tomography of the adrenal glands. After stabilisation of his cardiac rhythm and blood pressure with alpha and beta adrenergic blockade and anti-arrhythmic treatment the right adrenal gland, which contained the tumour, was successfully resected. The diagnosis of a phaeochromocytoma should be considered when recurrent ventricular arrhythmias are associated with intermittent hypertension after myocardial infarction. PMID:1739535

Cauda equina syndrome associated with multiple lumbar arachnoid cysts in ankylosing spondylitis: improvement following surgical therapy.

PubMed Central

Shaw, P J; Allcutt, D A; Bates, D; Crawford, P J

1990-01-01

A case of cauda equina syndrome with multiple lumbar arachnoid cysts complicating ankylosing spondylitis (AS) is described. The value of computerised tomography (CT) and magnetic resonance imaging (MRI) as a non-invasive means of establishing the diagnosis is emphasised. In contrast to previously reported cases the patient showed neurological improvement following surgical therapy. Surgery may be indicated in some patients, particularly when there is nerve root compression by the arachnoid cysts and when the patient is seen early before irreversible damage to the cauda equina has occurred. Images PMID:2292702

Terminology inaccuracies in the interpretation of imaging results in detection of cervical lymph node metastases in papillary thyroid cancer

PubMed Central

Mulla, Mubashir; Schulte, Klaus-Martin

2012-01-01

Cervical lymph nodes (CLNs) are the most common site of metastases in papillary thyroid cancer (PTC). Ultrasound scan (US) is the most commonly used imaging modality in the evaluation of CLNs in PTC. Computerised tomography (CT) and 18fluorodeoxyglucose positron emission tomography (18FDG PET–CT) are used less commonly. It is widely believed that the above imaging techniques should guide the surgical approach to the patient with PTC. Methods We performed a systematic review of imaging studies from the literature assessing the usefulness for the detection of metastatic CLNs in PTC. We evaluated the author's interpretation of their numeric findings specifically with regard to ‘sensitivity’ and ‘negative predictive value’ (NPV) by comparing their use against standard definitions of these terms in probabilistic statistics. Results A total of 16 studies used probabilistic terms to describe the value of US for the detection of LN metastases. Only 6 (37.5%) calculated sensitivity and NPV correctly. For CT, out of the eight studies, only 1 (12.5%) used correct terms to describe analytical results. One study looked at magnetic resonance imaging, while three assessed 18FDG PET–CT, none of which provided correct calculations for sensitivity and NPV. Conclusion Imaging provides high specificity for the detection of cervical metastases of PTC. However, sensitivity and NPV are low. The majority of studies reporting on a high sensitivity have not used key terms according to standard definitions of probabilistic statistics. Against common opinion, there is no current evidence that failure to find LN metastases on ultrasound or cross-sectional imaging can be used to guide surgical decision making. PMID:23781308

A semi-automatic technique to quantify complex tuberculous lung lesions on 18F-fluorodeoxyglucose positron emission tomography/computerised tomography images.

PubMed

Malherbe, Stephanus T; Dupont, Patrick; Kant, Ilse; Ahlers, Petri; Kriel, Magdalena; Loxton, André G; Chen, Ray Y; Via, Laura E; Thienemann, Friedrich; Wilkinson, Robert J; Barry, Clifton E; Griffith-Richards, Stephanie; Ellman, Annare; Ronacher, Katharina; Winter, Jill; Walzl, Gerhard; Warwick, James M

2018-06-25

There is a growing interest in the use of 18 F-FDG PET-CT to monitor tuberculosis (TB) treatment response. However, TB causes complex and widespread pathology, which is challenging to segment and quantify in a reproducible manner. To address this, we developed a technique to standardise uptake (Z-score), segment and quantify tuberculous lung lesions on PET and CT concurrently, in order to track changes over time. We used open source tools and created a MATLAB script. The technique was optimised on a training set of five pulmonary tuberculosis (PTB) cases after standard TB therapy and 15 control patients with lesion-free lungs. We compared the proposed method to a fixed threshold (SUV > 1) and manual segmentation by two readers and piloted the technique successfully on scans of five control patients and five PTB cases (four cured and one failed treatment case), at diagnosis and after 1 and 6 months of treatment. There was a better correlation between the Z-score-based segmentation and manual segmentation than SUV > 1 and manual segmentation in terms of overall spatial overlap (measured in Dice similarity coefficient) and specificity (1 minus false positive volume fraction). However, SUV > 1 segmentation appeared more sensitive. Both the Z-score and SUV > 1 showed very low variability when measuring change over time. In addition, total glycolytic activity, calculated using segmentation by Z-score and lesion-to-background ratio, correlated well with traditional total glycolytic activity calculations. The technique quantified various PET and CT parameters, including the total glycolytic activity index, metabolic lesion volume, lesion volumes at different CT densities and combined PET and CT parameters. The quantified metrics showed a marked decrease in the cured cases, with changes already apparent at month one, but remained largely unchanged in the failed treatment case. Our technique is promising to segment and quantify the lung scans of pulmonary tuberculosis patients in a semi-automatic manner, appropriate for measuring treatment response. Further validation is required in larger cohorts.

[A case of frontal lobe syndrome of post-traumatic origin].

PubMed

Gadecki, W; Ramsz-Walecka, I; Tomczyszyn, E

1999-01-01

The paper discusses the case of a patient who was subjected to forensic and psychiatric observation and was charged with appropriation of money to the detriment of the company she worked for by District Public Prosecutor's Office. History data indicate that she was employed in the said company over the period of 20 years as an accountant and until the disclosure of the crime she had had the company's full confidence. She enjoyed a fine reputation at the place of her residence as well. Several months before undertaking criminal actions she had sustained a head and chest injure as a result of a car accident. She was not subjected to hospitalisation then. Before she had not been penalized administratively or legally. She had not suffered from head injuries with a loss of consciousness. During forensic and psychiatric observation, psychiatric, psychological, neurological and electroencephalographic examinations were carried out, skull and chest plain films were taken and computerised tomography of head was conducted. Clinically it was diagnosed as a frontal organic brain damage syndrome complicated by depression. Experts' examinations were steered by psychopathological image, especially axial symptoms of defective function of the frontal lobe, i.e. lack of initiative and spontaneity, deficiency of higher emotions, decline of criticism and lowering of psychomotor drive. Although psychological examination showed that intelligence quotient and the results of 'organic tests' were within normal range, qualitative analysis of the structure of mental functions disclosed impairment of abstract thinking, especially using associative processes. Essential data were gathered from computerised tomography of head which demonstrated cortical atrophy of frontal and temporal lobes and pericentral gyri. However, neurological and electroencephalographic examinations and skull plain film did not bring any significant information.

Heart CT scan

MedlinePlus

... Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agatston ... table that slides into the center of the CT scanner. You will lie on your back with ...

Modelling of aortic aneurysm and aortic dissection through 3D printing.

PubMed

Ho, Daniel; Squelch, Andrew; Sun, Zhonghua

2017-03-01

The aim of this study was to assess if the complex anatomy of aortic aneurysm and aortic dissection can be accurately reproduced from a contrast-enhanced computed tomography (CT) scan into a three-dimensional (3D) printed model. Contrast-enhanced cardiac CT scans from two patients were post-processed and produced as 3D printed thoracic aorta models of aortic aneurysm and aortic dissection. The transverse diameter was measured at five anatomical landmarks for both models, compared across three stages: the original contrast-enhanced CT images, the stereolithography (STL) format computerised model prepared for 3D printing and the contrast-enhanced CT of the 3D printed model. For the model with aortic dissection, measurements of the true and false lumen were taken and compared at two points on the descending aorta. Three-dimensional printed models were generated with strong and flexible plastic material with successful replication of anatomical details of aortic structures and pathologies. The mean difference in transverse vessel diameter between the contrast-enhanced CT images before and after 3D printing was 1.0 and 1.2 mm, for the first and second models respectively (standard deviation: 1.0 mm and 0.9 mm). Additionally, for the second model, the mean luminal diameter difference between the 3D printed model and CT images was 0.5 mm. Encouraging results were achieved with regards to reproducing 3D models depicting aortic aneurysm and aortic dissection. Variances in vessel diameter measurement outside a standard deviation of 1 mm tolerance indicate further work is required into the assessment and accuracy of 3D model reproduction. © 2017 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.

Breast implant-associated anaplastic large cell lymphoma: a case report and literature review.

PubMed

Hwang, Mei-Ju; Brown, Hamish; Murrin, Richard; Momtahan, Navid; Sterne, Guy D

2015-06-01

Breast implant-associated anaplastic large cell lymphoma (ALCL) is a rare new clinical entity. The incidence is 0.3 % per 100,000 women per year. Patients present with non-specific implant-related complications resulting in delayed diagnosis. We present such a case to raise awareness and discuss management. A 48-year-old female presented with a 3-month history of left breast pain and swelling. She had undergone multiple bilateral augmentations 8 years previously. Triple assessment revealed a seroma, and a magnetic resonance imaging scan excluded implant rupture. Cytology showed a typical cells with mitotic activity which lead to removal of implants and a left capsulectomy. Final histology revealed an anaplastic lymphoma kinase (ALK) negative ALCL confined to the capsule. A computerised tomography scan and bone marrow biopsy excluded systemic disease, but due to later identified B symptoms, she received CHOP chemotherapy under the care of the haematologists. ALK-negative ALCL is associated with breast implants, and any persistent late onset seroma or breast symptoms should raise the suspicion of ALK-negative ALCL as a differential diagnosis. The recommended treatment is surgical removal of the implant including a full capsulectomy, highlighting the suspicion of ALCL to the pathologist. Exclusion of systematic disease is also recommended in all patients, and the need for adjuvant therapy should be addressed on an individual case basis. For disease confined to the capsule, adjuvant chemoradiotherapy is not needed. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Does rapid maxillary expansion affect nasopharyngeal airway? A prospective Cone Beam Computerised Tomography (CBCT) based study.

PubMed

Almuzian, Mohammed; Ju, Xiangyang; Almukhtar, Anas; Ayoub, Ashraf; Al-Muzian, Lubna; McDonald, Jim P

2018-02-01

There is limited literature discussing the three dimnesional (3D) impact of rapid maxillary expansion (RME) on upper airway. The purpose of this prospective Cone Beam Computerised Tomography (CBCT) based study is to assess the immediate 3D effects and to correlate the volumteric changes in the upper naspharyngeal airway spaces secondary to RME. Seventeen participants (8 male, 9 female, with a mean age of 12.6 ± 1.8 years), who required RME for the management of narrow maxillary arch, were recruited for this study. The prescribed expansion regimen was quarter turn (0.25 mm), twice a day until over-expansion was achieved. The mean period for the active phase was 14 days with a range of 12-21 days. Pretreatment (T1) and immediate post-expansion (T2) CBCT images were obtained and then processed using ITK snap and OnDemand3D softwar packages. Paired t-test and Interclass Correlation Coefficient (ICC) were used to assess the reproducibility of the measurements, student t-test (P < 0.05) and Pearson Correlation Coefficient (PCC) were applied to evaluate the volumetric changes in the nasopharyngeal airway spaces, linear dentolaveolar changes and correlate these changes. Though, the data of one patient was excluded from the study, owing to major differences (>5 degrees) in the head and neck posture between T1 and T2 CBCT scans, the study' findings shows that bonded RME is an effective dentoalveolar expander in growing patients (P= 0.01) with an average expansion of 3.7 mm and 2.8 mm in males and females respectively. Likewise, the upper nasopharynx (UNP) expanded significantly (15.2% in males and 12% in females). In comparison, the upper retropalatal space (URP) was significantly reduced, by almost one sixth of its original volume, more in males than females, 11.2% and 2.8% respectively. A strong direct correlation between the maxillary sinus volumetric changes, and between appliance expansion and dentoalveolar expansion were evident (PCC = 0.86, 0.75, respectively). There was also a moderate correlation between changes in the UNP and URP spaces. RME was found to be an effective dentoalveolar expander and significantly augment the UNP and minimize the URP space. A similar comparative clinical study with long-term follow-up would be beneficial in accurately deteremining the clinical impact of RME on the airway and breathing as well as the stability of these effects. Copyright © 2015 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

Relationship between the Self-Rating Anxiety Scale score and the success rate of 64-slice computed tomography coronary angiography.

PubMed

Li, Hui; Jin, Dan; Qiao, Fang; Chen, Jianchang; Gong, Jianping

Computed tomography coronary angiography, a key method for obtaining coronary artery images, is widely used to screen for coronary artery diseases due to its noninvasive nature. In China, 64-slice computed tomography systems are now the most common models. As factors that directly affect computed tomography performance, heart rate and rhythm control are regulated by the autonomic nervous system and are highly related to the emotional state of the patient. The aim of this prospective study is to use a pre-computed tomography scan Self-Rating Anxiety Scale assessment to analyze the effects of tension and anxiety on computed tomography coronary angiography success. Subjects aged 18-85 years who were planned to undergo computed tomography coronary angiography were enrolled; 1 to 2 h before the computed tomography scan, basic patient data (gender, age, heart rate at rest, and family history) and Self-Rating Anxiety Scale score were obtained. The same group of imaging department doctors, technicians, and nurses performed computed tomography coronary angiography for all the enrolled subjects and observed whether those subjects could finish the computed tomography coronary angiography scan and provide clear, diagnostically valuable images. Participants were divided into successful (obtained diagnostically useful coronary images) and unsuccessful groups. Basic data and Self-Rating Anxiety Scale scores were compared between the groups. The Self-Rating Anxiety Scale standard score of the successful group was lower than that of the unsuccessful group (P = 0.001). As the Self-Rating Anxiety Scale standard score rose, the success rate of computed tomography coronary angiography decreased. The Self-Rating Anxiety Scale score has a negative relationship with computed tomography coronary angiography success. Anxiety can be a disadvantage in computed tomography coronary angiography examination. The pre-computed tomography coronary angiography scan Self-Rating Anxiety Scale score may be a useful tool for assessing whether a computed tomography coronary angiography scan will be successful or not. © The Author(s) 2015.

Fabrication and characterisation of a novel biomimetic anisotropic ceramic/polymer-infiltrated composite material.

PubMed

Al-Jawoosh, Sara; Ireland, Anthony; Su, Bo

2018-04-10

To fabricate and characterise a novel biomimetic composite material consisting of aligned porous ceramic preforms infiltrated with polymer. Freeze-casting was used to fabricate and control the microstructure and porosity of ceramic preforms, which were subsequently infiltrated with 40-50% by volume UDMA-TEGDMA polymer. The composite materials were then subjected to characterisation, namely density, compression, three-point bend, hardness and fracture toughness testing. Samples were also subjected to scanning electron microscopy and computerised tomography (Micro-CT). Three-dimensional aligned honeycomb-like ceramic structures were produced and full interpenetration of the polymer phase was observed using micro-CT. Depending on the volume fraction of the ceramic preform, the density of the final composite ranged from 2.92 to 3.36g/cm 3 , compressive strength ranged from 206.26 to 253.97MPa, flexural strength from 97.73 to 145.65MPa, hardness ranged from 1.46 to 1.62GPa, and fracture toughness from 3.91 to 4.86MPam 1/2 . Freeze-casting provides a novel method to engineer composite materials with a unique aligned honeycomb-like interpenetrating structure, consisting of two continuous phases, inorganic and organic. There was a correlation between the ceramic fraction and the subsequent, density, strength, hardness and fracture toughness of the composite material. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

MULTIMODAL IMAGING OF ACUTE EXUDATIVE POLYMORPHOUS VITELLIFORM MACULOPATHY WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY AND ADAPTIVE OPTICS SCANNING LASER OPHTHALMOSCOPY.

PubMed

Skondra, Dimitra; Nesper, Peter L; Fawzi, Amani A

2017-05-16

To report a case of acute exudative polymorphous vitelliform maculopathy including the findings of optical coherence tomography angiography and adaptive optics scanning laser ophthalmoscopy. Findings on clinical examination, color fundus photography, spectral-domain optical coherence tomography, infrared reflectance, autofluorescence, optical coherence tomography angiography, and adaptive optics scanning laser ophthalmoscopy. A 54-year-old white man with no significant medical history and history of smoking presented with bilateral multiple serous and vitelliform detachments consistent with acute exudative polymorphous vitelliform maculopathy. Extensive infectious, inflammatory, and malignancy workup was negative. Spectral-domain optical coherence tomography showed thickened, hyperreflective ellipsoid zone, subretinal fluid, and focal as well as diffuse subretinal hyperreflective material corresponding to the vitelliform lesions. Optical coherence tomography angiography showed normal retinal and choroidal vasculature, whereas adaptive optics scanning laser ophthalmoscopy showed circular focal "target" lesions at the level of the photoreceptors in the area of foveal detachment. Multimodal imaging is valuable in evaluating patients with acute exudative polymorphous vitelliform maculopathy.

Positron Emission Tomography - Computed Tomography (PET/CT)

MedlinePlus

... A-Z Positron Emission Tomography - Computed Tomography (PET/CT) Positron emission tomography (PET) uses small amounts of ... What is Positron Emission Tomography – Computed Tomography (PET/CT) Scanning? Positron emission tomography, also called PET imaging ...

Cyborg practices: call-handlers and computerised decision support systems in urgent and emergency care.

PubMed

Pope, Catherine; Halford, Susan; Turnbull, Joanne; Prichard, Jane

2014-06-01

This article draws on data collected during a 2-year project examining the deployment of a computerised decision support system. This computerised decision support system was designed to be used by non-clinical staff for dealing with calls to emergency (999) and urgent care (out-of-hours) services. One of the promises of computerised decisions support technologies is that they can 'hold' vast amounts of sophisticated clinical knowledge and combine it with decision algorithms to enable standardised decision-making by non-clinical (clerical) staff. This article draws on our ethnographic study of this computerised decision support system in use, and we use our analysis to question the 'automated' vision of decision-making in healthcare call-handling. We show that embodied and experiential (human) expertise remains central and highly salient in this work, and we propose that the deployment of the computerised decision support system creates something new, that this conjunction of computer and human creates a cyborg practice.

Pharmacokinetics Application in Biophysics Experiments

NASA Astrophysics Data System (ADS)

Millet, Philippe; Lemoigne, Yves

Among the available computerised tomography devices, the Positron Emission Tomography (PET) has the advantage to be sensitive to pico-molar concentrations of radiotracers inside living matter. Devices adapted to small animal imaging are now commercially available and allow us to study the function rather than the structure of living tissues by in vivo analysis. PET methodology, from the physics of electron-positron annihilation to the biophysics involved in tracers, is treated by other authors in this book. The basics of coincidence detection, image reconstruction, spatial resolution and sensitivity are discussed in the paper by R. Ott. The use of compartment analysis combined with pharmacokinetics is described here to illustrate an application to neuroimaging and to show how parametric imaging can bring insight on the in vivo bio-distribution of a radioactive tracer with small animal PET scanners. After reporting on the use of an intracerebral β+ radiosensitive probe (βP), we describe a small animal PET experiment used to measure the density of 5HT 1 a receptors in rat brain.

Simultaneous fast scanning XRF, dark field, phase-, and absorption contrast tomography

NASA Astrophysics Data System (ADS)

Medjoubi, Kadda; Bonissent, Alain; Leclercq, Nicolas; Langlois, Florent; Mercère, Pascal; Somogyi, Andrea

2013-09-01

Scanning hard X-ray nanoprobe imaging provides a unique tool for probing specimens with high sensitivity and large penetration depth. Moreover, the combination of complementary techniques such as X-ray fluorescence, absorption, phase contrast and dark field imaging gives complete quantitative information on the sample structure, composition and chemistry. The multi-technique "FLYSCAN" data acquisition scheme developed at Synchrotron SOLEIL permits to perform fast continuous scanning imaging and as such makes scanning tomography techniques feasible in a time-frame well-adapted to typical user experiments. Here we present the recent results of simultaneous fast scanning multi-technique tomography performed at Soleil. This fast scanning scheme will be implemented at the Nanoscopium beamline for large field of view 2D and 3D multimodal imaging.

Infantile Autism and Computerized Tomography Brain-Scan Findings: Specific versus Nonspecific Abnormalities.

ERIC Educational Resources Information Center

Balottin, Umberto; And Others

1989-01-01

The study of computerized tomography brain-scan findings with 45 autistic and 19 control subjects concluded that autism is nonspecifically associated with brain-scan abnormalities, and that other nonorganic, as well as organic, factors should be taken into account. (Author/DB)

Iliopsoas bursitis and tendinitis. A review.

PubMed

Johnston, C A; Wiley, J P; Lindsay, D M; Wiseman, D A

1998-04-01

This review examines the diagnosis and management of iliopsoas bursitis and/or tendinitis. It is a relatively uncommon and unrecognised cause of anterior hip pain and anterior snapping hip. In view of its pathology, iliopsoas bursitis might be better referred to as iliopsoas syndrome. It can usually be diagnosed by history and physical examination, though real time ultrasound may be useful in confirming the diagnosis. Magnetic resonance and computerised tomography imaging have limited roles in its diagnosis, but may identify other pathology or surgical lesions. Nonoperative management has not been well established. Surgical management does not guarantee treatment success. There is a need for further research into both diagnostic and treatment options for those patients with iliopsoas bursitis/tendinitis.

Immunisation registers in Italy: a patchwork of computerisation.

PubMed

Alfonsi, V; D'Ancona, F; Rota, M C; Giambi, C; Ranghiasci, A; Iannazzo, S

2012-04-26

In Italy, the 21 regional health authorities are in charge of organising and implementing their own vaccination strategy, based on the national vaccine plan. Immunisation coverage varies greatly among the regions for certain vaccines. Efforts to increase childhood immunisation coverage have included initiatives to develop and implement computerised immunisation registers in as many regions as possible. We undertook a cross-sectional online survey in July 2011 to provide an updated picture of the use, heterogeneity and main functions of different computerised immunisation registers used in the Italian regions and to understand the flow of information from local health units to the regional authorities and to the Ministry of Health. Comparing current data with those obtained in 2007, a substantial improvement is evident. A total of 15 regions are fully computerised (previously nine), with 83% of local health units equipped with a computerised register (previously 70%). Eight of the 15 fully computerised regions use the same software, simplifying data sharing. Only four regions are able to obtain data in real time from local health units. Despite the progress made, the capacity to monitor vaccination coverage and to exchange data appears still limited.

Pediatric minor head trauma: do cranial CT scans change the therapeutic approach?

PubMed

Andrade, Felipe P; Montoro, Roberto; Oliveira, Renan; Loures, Gabriela; Flessak, Luana; Gross, Roberta; Donnabella, Camille; Puchnick, Andrea; Suzuki, Lisa; Regacini, Rodrigo

2016-10-01

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. 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. 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%. 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.

Attitudes of nursing staff towards computerisation: a case of two hospitals in Nairobi, Kenya

PubMed Central

2014-01-01

Background The health sector is faced with constant changes as new approaches to tackle illnesses are unveiled through research. Information, communication and technology have greatly transformed healthcare practice the world over. Nursing is continually exposed to a variety of changes. Variables including age, educational level, years worked in nursing, computer knowledge and experience have been found to influence the attitudes of nurses towards computerisation. The purpose of the study was to determine the attitudes of nurses towards the use of computers and the factors that influence these attitudes. Methods This cross sectional descriptive study was conducted among staff nurses working at one public hospital (Kenyatta National Hospital, (KNH) and one private hospital (Aga Khan University Hospital (AKUH). A convenience sample of 200 nurses filled the questionnaires. Data was collected using the modified Nurses’ Attitudes Towards Computerisation (NATC) questionnaire. Results Nurses had a favorable attitude towards computerisation. Non-users had a significantly higher attitude score compared to the users (p = 0.0274). Statistically significant associations were observed with age (p = 0.039), level of education (p = 0.025), duration of exposure to computers (p = 0.025) and attitudes towards computerisation. Conclusion Generally, nurses have positive attitudes towards computerisation. This information is important for the planning and implementation of computerisation in the hospital as suggested in other studies. PMID:24774008

Nuclear Heart Scan

MedlinePlus

... into your blood and travels to your heart. Nuclear heart scans use single photon emission computed tomography (SPECT) or cardiac positron emission tomography (PET) to detect the energy from the tracer to make pictures of your ...

Diagnostic ability of computed tomography using DentaScan software in endodontics: case reports.

PubMed

Siotia, Jaya; Gupta, Sunil K; Acharya, Shashi R; Saraswathi, Vidya

2011-01-01

Radiographic examination is essential in diagnosis and treatment planning in endodontics. Conventional radiographs depict structures in two dimensions only. The ability to assess the area of interest in three dimensions is advantageous. Computed tomography is an imaging technique which produces three-dimensional images of an object by taking a series of two-dimensional sectional X-ray images. DentaScan is a computed tomography software program that allows the mandible and maxilla to be imaged in three planes: axial, panoramic, and cross-sectional. As computed tomography is used in endodontics, DentaScan can play a wider role in endodontic diagnosis. It provides valuable information in the assessment of the morphology of the root canal, diagnosis of root fractures, internal and external resorptions, pre-operative assessment of anatomic structures etc. The aim of this article is to explore the clinical usefulness of computed tomography and DentaScan in endodontic diagnosis, through a series of four cases of different endodontic problems.

Evaluation of a continuous-rotation, high-speed scanning protocol for micro-computed tomography.

PubMed

Kerl, Hans Ulrich; Isaza, Cristina T; Boll, Hanne; Schambach, Sebastian J; Nolte, Ingo S; Groden, Christoph; Brockmann, Marc A

2011-01-01

Micro-computed tomography is used frequently in preclinical in vivo research. Limiting factors are radiation dose and long scan times. The purpose of the study was to compare a standard step-and-shoot to a continuous-rotation, high-speed scanning protocol. Micro-computed tomography of a lead grid phantom and a rat femur was performed using a step-and-shoot and a continuous-rotation protocol. Detail discriminability and image quality were assessed by 3 radiologists. The signal-to-noise ratio and the modulation transfer function were calculated, and volumetric analyses of the femur were performed. The radiation dose of the scan protocols was measured using thermoluminescence dosimeters. The 40-second continuous-rotation protocol allowed a detail discriminability comparable to the step-and-shoot protocol at significantly lower radiation doses. No marked differences in volumetric or qualitative analyses were observed. Continuous-rotation micro-computed tomography significantly reduces scanning time and radiation dose without relevantly reducing image quality compared with a normal step-and-shoot protocol.

Brain PET scan

MedlinePlus

... tissues are working. Other imaging tests, such as magnetic resonance imaging ( MRI ) and computed tomography ( CT ) scans only reveal ... M, Hellwig S, Kloppel S, Weiller C. Functional neuroimaging: functional magnetic resonance imaging, positron emission tomography, and single-photon emission computed ...

Frequency multiplexed long range swept source optical coherence tomography

PubMed Central

Zurauskas, Mantas; Bradu, Adrian; Podoleanu, Adrian Gh.

2013-01-01

We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample. PMID:23760762

Assessment of the Role of Different Imaging Modalities with Emphasis on Fdg Pet/Ct in the Management of Well Differentiated Thyroid Cancer (WDTC).

PubMed

Kendi A, Tuba Karagulle; Mudalegundi, Shwetha; Switchenko, Jeffrey; Lee, Daniel; Halkar, Raghuveer; Chen, Amy Y

2016-01-01

Positron emission tomography/computed tomography is suggested to have a role in detection of iodine negative recurrence in well differentiated thyroid cancer. The aim of this study is to identify role of different imaging modalities in the management of well differentiated thyroid cancer. We reviewed 900 well differentiated thyroid cancer patients after post-thyroidectomy who underwent recombinant human thyroid stimulating hormone stimulated Sodium Iodide I 131 imaging. Out of 900 patients, 74 had positron emission tomography/computed tomography. Multivariate analysis was performed by controlling positron emission tomography/computed tomography, Sodium Iodide I 131 scan, neck ultrasonography, age, sex, primary tumor size, stage, histology, thyroglobulin. Patients were grouped according to results of Sodium Iodide I 131 scan and positron emission tomography/computed tomography. Positron emission tomography/computed tomography was positive in 23 of 74 patients. The sensitivity for positron emission tomography was 11/11(100%), the specificity was 51/63 (81.0%), the positive predictive value was 11/23 (47.8%), and the negative predictive value was 51/51 (100%). The sensitivity for the neck ultrasonography was 4/8 (50%), the specificity was 53/60 (88.3%), positive predictive value was 4/11 (36.4%), and negative predictive value was 53/57 (93.0%). 50% of patients who had Sodium Iodide I 131 negative scan and positive positron emission tomography/computed tomography had a change in management. Thirty-six percent with positive neck ultrasonography had a change in management. Out of 11 recurrences, 6 had distant metastatic disease, and 5/11 had regional nodal disease. Neck ultrasonography showed nodal metastasis in 4/5 (80%). Positron emission tomography/computed tomography altered management in the presence of a high thyroglobulin level and a negative Sodium Iodide I 131 scan. Neck ultrasonography should be the first line of imaging with rising thyroglobulin levels. Positron emission tomography/computed tomography should be considered for cases with high thyroglobulin levels and normal neck ultrasonography to look for distant metastatic disease.

Locating knots by industrial tomography- A feasibility study

Treesearch

Fred W. Taylor; Francis G. Wagner; Charles W. McMillin; Ira L. Morgan; Forrest F. Hopkins

1984-01-01

Industrial photon tomography was used to scan four southern pine logs and one red oak log. The logs were scanned at 16 cross-sectional slice planes located 1 centimeter apart along their longitudinal axes. Tomographic reconstructions were made from the scan data collected at these slice planes, and a cursory image analysis technique was developed to locate the log...

Tangential scanning of hardwood logs: developing an industrial computer tomography scanner

Treesearch

Nand K. Gupta; Daniel L. Schmoldt; Bruce Isaacson

1999-01-01

It is generally believed that noninvasive scanning of hardwood logs such as computer tomography (CT) scanning prior to initial breakdown will greatly improve the processing of logs into lumber. This belief, however, has not translated into rapid development and widespread installation of industrial CT scanners for log processing. The roadblock has been more operational...

Outcome of surgically treated non-missile traumatic depressed skull fracture.

PubMed

Nnadi, M O N; Bankole, O B; Arigbabu, S O

2014-12-01

To determine the functional outcome and infection rate in patients who were surgically treated for non-missile traumatic depressed skull fractures. It is a prospective cross-sectional descriptive study carried out on computerised tomography scanned depressed skull fractures surgically treated in Lagos University Teaching Hospital, Lagos from October 2008 to September 2009. Data were collected using structured proforma in accident and emergency, theatre, wards, and in outpatient clinic. Data collected included age, gender, occupation, type of depressed fracture, aetiology, clinicaland radiological findings, type of surgery done, complications, and outcome of treatment. Data was analysed using EPI info 2002 software. A total of 17 patients were studied. There were 12males and 5females. Fifteen (88.2%) of the patients were0- 40years. The aetiology was road traffic accident in 82.4% of cases. Fourteen (82.4%) of the patients had open depressed skull fractures, while 17.6% had closed depressed skull fractures. Five (29.4%) of the patients had wound infection. Two (22.2%) of thepatients operated within 48hours had wound infection, while 37.5% of those operated after 48hours had wound infection. There was no infection among patients who had primary bone fragments replaced. Fifteen (88.2%) of the patients had good functional outcome. The functional outcome in this study is good but the infection rate is high. Primary bone fragments should be replaced whenever possible as it prevents the need for cranioplasty and there is no relative risk of increased infection rate.

[Preoperative CT Scan in middle ear cholesteatoma].

PubMed

Sethom, Anissa; Akkari, Khemaies; Dridi, Inès; Tmimi, S; Mardassi, Ali; Benzarti, Sonia; Miled, Imed; Chebbi, Mohamed Kamel

2011-03-01

To compare preoperative CT scan finding and per-operative lesions in patients operated for middle ear cholesteatoma, A retrospective study including 60 patients with cholesteatoma otitis diagnosed and treated within a period of 5 years, from 2001 to 2005, at ENT department of Military Hospital of Tunis. All patients had computed tomography of the middle and inner ear. High resolution CT scan imaging was performed using millimetric incidences (3 to 5 millimetres). All patients had surgical removal of their cholesteatoma using down wall technic. We evaluated sensitivity, specificity and predictive value of CT-scan comparing otitic damages and CT finding, in order to examine the real contribution of computed tomography in cholesteatoma otitis. CT scan analysis of middle ear bone structures shows satisfaction (with 83% of sensibility). The rate of sensibility decrease (63%) for the tympanic raff. Predictive value of CT scan for the diagnosis of cholesteatoma was low. However, we have noticed an excellent sensibility in the analysis of ossicular damages (90%). Comparative frontal incidence seems to be less sensible for the detection of facial nerve lesions (42%). But when evident on CT scan findings, lesions of facial nerve were usually observed preoperatively (spécificity 78%). Predictive value of computed tomography for the diagnosis of perilymphatic fistulae (FL) was low. In fact, CT scan imaging have showed FL only for four patients among eight. Best results can be obtained if using inframillimetric incidences with performed high resolution computed tomography. Preoperative computed tomography is necessary for the diagnosis and the evaluation of chronic middle ear cholesteatoma in order to show extending lesion and to detect complications. This CT analysis and surgical correlation have showed that sensibility, specificity and predictive value of CT-scan depend on the anatomic structure implicated in cholesteatoma damages.

Lung Hot Spot Without Corresponding Computed Tomography Abnormality on Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Artifactual or Real, Iatrogenic or Pathologic?

PubMed

Liu, Yiyan

Focal lung uptake without corresponding lesions or abnormalities on computed tomography (CT) scan poses a dilemma in the interpretation of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). A limited number of case reports have previously suggested an artifactual or iatrogenic nature of the uptake. In the present study, 8 relevant cases were included within a retrospective search of the database. Medical records were reviewed for follow-up radiological and pathologic information. In 7 of 8 cases with focal increased FDG uptake but no corresponding lesions or abnormalities on CT scan, the lung hot spots were artifactual or iatrogenic upon follow-up diagnostic chest CT or repeated PET/CT or both the scans. Microemboli were most likely a potential cause of the pulmonary uptake, with or without partial paravenous injection. One case in the series had a real pulmonary lesion demonstrated on follow-up PET/CT scans and on surgical pathology, although the initial integrated CT and follow-up diagnostic chest CT scans revealed negative findings to demonstrate pulmonary abnormalities corresponding to the hot spot on the PET scan. In conclusion, the finding of a lung hot spot in the absence of anatomical abnormality on FDG PET/CT was most likely artifactual or iatrogenic, but it might also represent a real pulmonary lesion. Nonvisualization of anatomical abnormality could be because of its small size and position directly overlying a segmental vessel. Further image follow-up is necessary and important to clarify the nature of the uptake. Copyright © 2017 Elsevier Inc. All rights reserved.

The Physics of Physical Examinations.

ERIC Educational Resources Information Center

Patterson, James D.

1989-01-01

Discussed are several topics on medical imaging including x-rays and Computer Assisted Tomography (CAT) scans, magnetic resonance imaging, fiber optics endoscopy, nuclear medicine and bone scans, positron-emission tomography, and ultrasound. The concepts of radiation dosage, electrocardiograms, and laser therapy are included. (YP)

MMX-I: data-processing software for multimodal X-ray imaging and tomography.

PubMed

Bergamaschi, Antoine; Medjoubi, Kadda; Messaoudi, Cédric; Marco, Sergio; Somogyi, Andrea

2016-05-01

A new multi-platform freeware has been developed for the processing and reconstruction of scanning multi-technique X-ray imaging and tomography datasets. The software platform aims to treat different scanning imaging techniques: X-ray fluorescence, phase, absorption and dark field and any of their combinations, thus providing an easy-to-use data processing tool for the X-ray imaging user community. A dedicated data input stream copes with the input and management of large datasets (several hundred GB) collected during a typical multi-technique fast scan at the Nanoscopium beamline and even on a standard PC. To the authors' knowledge, this is the first software tool that aims at treating all of the modalities of scanning multi-technique imaging and tomography experiments.

Introduction to Seismic Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowe, Charlotte Anne

2017-11-21

Tomography is a method of obtaining an image of a 3d object by observing the behavior of energy transmissions through the object. The image is obtained by Interrogating the object with Energy sources at a variety of Locations and observing the Object’s effects on the energy at a Variety of sensors. Tomography was first Used to build 3-dimensional Scans through Human bodies. These Are called computed Tomographic (ct) scans.

Incidence of a single subsegmental mismatched perfusion defect in single-photon emission computed tomography and planar ventilation/perfusion scans.

PubMed

Stubbs, Matthew; Chan, Kenneth; McMeekin, Helena; Navalkissoor, Shaunak; Wagner, Thomas

2017-02-01

This study aims to compare the incidence of ventilation/perfusion (V/Q) scans interpreted as indeterminate for the diagnosis of pulmonary embolism (PE) using single-photon emission computed tomography (SPECT) versus planar scintigraphy and to consider the effect of variable interpretation of single subsegmental V/Q mismatch (SSM). A total of 1300 consecutive V/Q scans were retrospectively reviewed. After exclusion and matching for age and sex, 542 SPECT and 589 planar scans were included in the analysis. European Association of Nuclear Medicine guidelines were used to interpret the V/Q scans, initially interpreting SSM as negative scans. Patients with SSM were followed up for 3 months and further imaging for PE was collected. Indeterminate scans were significantly fewer in the SPECT than the planar group on the basis of the initial report (7.7 vs. 12.2%, P<0.05). This is irrespective of classification of SSM as a negative scan (4.6 vs. 12.1%, P<0.0001) or an indeterminate scan (8.3 vs. 12.2%, P<0.05). Of the 21 patients who had SSM, 19 underwent computer tomography pulmonary angiogram and embolism was found in one patient. None of these patients died at the 3-month follow-up. V/Q SPECT has greater diagnostic certainty of PE, with a 41% reduction in an indeterminate scan compared with planar scintigraphy. This is irrespective of the clinician's interpretation of SSM as negative or intermediate probability. Patients with SSM would not require further computer tomography pulmonary angiogram imaging.

Scanning transmission ion micro-tomography (STIM-T) of biological specimens.

PubMed

Schwertner, Micheal; Sakellariou, Arthur; Reinert, Tilo; Butz, Tilman

2006-05-01

Computed tomography (CT) was applied to sets of Scanning Transmission Ion Microscopy (STIM) projections recorded at the LIPSION ion beam laboratory (Leipzig) in order to visualize the 3D-mass distribution in several specimens. Examples for a test structure (copper grid) and for biological specimens (cartilage cells, cygospore) are shown. Scanning Transmission Micro-Tomography (STIM-T) at a resolution of 260 nm was demonstrated for the first time. Sub-micron features of the Cu-grid specimen were verified by scanning electron microscopy. The ion energy loss measured during a STIM-T experiment is related to the mass density of the specimen. Typically, biological specimens can be analysed without staining. Only shock freezing and freeze-drying is required to preserve the ultra-structure of the specimen. The radiation damage to the specimen during the experiment can be neglected. This is an advantage compared to other techniques like X-ray micro-tomography. At present, the spatial resolution is limited by beam position fluctuations and specimen vibrations.

Clinical and cost-effectiveness of computerised cognitive behavioural therapy for depression in primary care: Design of a randomised trial

PubMed Central

de Graaf, L Esther; Gerhards, Sylvia AH; Evers, Silvia MAA; Arntz, Arnoud; Riper, Heleen; Severens, Johan L; Widdershoven, Guy; Metsemakers, Job FM; Huibers, Marcus JH

2008-01-01

Background Major depression is a common mental health problem in the general population, associated with a substantial impact on quality of life and societal costs. However, many depressed patients in primary care do not receive the care they need. Reason for this is that pharmacotherapy is only effective in severely depressed patients and psychological treatments in primary care are scarce and costly. A more feasible treatment in primary care might be computerised cognitive behavioural therapy. This can be a self-help computer program based on the principles of cognitive behavioural therapy. Although previous studies suggest that computerised cognitive behavioural therapy is effective, more research is necessary. Therefore, the objective of the current study is to evaluate the (cost-) effectiveness of online computerised cognitive behavioural therapy for depression in primary care. Methods/Design In a randomised trial we will compare (a) computerised cognitive behavioural therapy with (b) treatment as usual by a GP, and (c) computerised cognitive behavioural therapy in combination with usual GP care. Three hundred mild to moderately depressed patients (aged 18–65) will be recruited in the general population by means of a large-scale Internet-based screening (N = 200,000). Patients will be randomly allocated to one of the three treatment groups. Primary outcome measure of the clinical evaluation is the severity of depression. Other outcomes include psychological distress, social functioning, and dysfunctional beliefs. The economic evaluation will be performed from a societal perspective, in which all costs will be related to clinical effectiveness and health-related quality of life. All outcome assessments will take place on the Internet at baseline, two, three, six, nine, and twelve months. Costs are measured on a monthly basis. A time horizon of one year will be used without long-term extrapolation of either costs or quality of life. Discussion Although computerised cognitive behavioural therapy is a promising treatment for depression in primary care, more research is needed. The effectiveness of online computerised cognitive behavioural therapy without support remains to be evaluated as well as the effects of computerised cognitive behavioural therapy in combination with usual GP care. Economic evaluation is also needed. Methodological strengths and weaknesses are discussed. Trial registration The study has been registered at the Netherlands Trial Register, part of the Dutch Cochrane Centre (ISRCTN47481236). PMID:18590518

Advanced Computed-Tomography Inspection System

NASA Technical Reports Server (NTRS)

Harris, Lowell D.; Gupta, Nand K.; Smith, Charles R.; Bernardi, Richard T.; Moore, John F.; Hediger, Lisa

1993-01-01

Advanced Computed Tomography Inspection System (ACTIS) is computed-tomography x-ray apparatus revealing internal structures of objects in wide range of sizes and materials. Three x-ray sources and adjustable scan geometry gives system unprecedented versatility. Gantry contains translation and rotation mechanisms scanning x-ray beam through object inspected. Distance between source and detector towers varied to suit object. System used in such diverse applications as development of new materials, refinement of manufacturing processes, and inspection of components.

MMX-I: data-processing software for multimodal X-ray imaging and tomography

PubMed Central

Bergamaschi, Antoine; Medjoubi, Kadda; Messaoudi, Cédric; Marco, Sergio; Somogyi, Andrea

2016-01-01

A new multi-platform freeware has been developed for the processing and reconstruction of scanning multi-technique X-ray imaging and tomography datasets. The software platform aims to treat different scanning imaging techniques: X-ray fluorescence, phase, absorption and dark field and any of their combinations, thus providing an easy-to-use data processing tool for the X-ray imaging user community. A dedicated data input stream copes with the input and management of large datasets (several hundred GB) collected during a typical multi-technique fast scan at the Nanoscopium beamline and even on a standard PC. To the authors’ knowledge, this is the first software tool that aims at treating all of the modalities of scanning multi-technique imaging and tomography experiments. PMID:27140159

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 ...

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

USDA-ARS?s Scientific Manuscript database

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...

Military surgery in the 21st century.

PubMed

Mellor, S G

2006-01-01

The battlefield has changed. UK and US Forces in Iraq and Afghanistan are engaged in asymmetric, three bloc warfare. Three bloc warfare indicates that what is effectively war-fighting occurs in parallel with peace-keeping and humanitarian operations. Casualties are numerically lower than in previous conflicts but many survivors are horrifically mutilated as body armour prevents the fatal injury in this severely injured group. Rapid evacuation of severely injured from the point of injury, usually by helicopter, provides extreme challenges for surgical teams. Damage control surgery requires support in the form of environmental control, adequate diagnostics (including computerised tomography) and effective intensive care facilities if the patient is to survive. Teams need to be highly trained and to have experience of complex surgery and trauma. They must be adequately resourced if lives are to be saved.

The impact of different cone beam computed tomography and multi-slice computed tomography scan parameters on virtual three-dimensional model accuracy using a highly precise ex vivo evaluation method.

PubMed

Matta, Ragai-Edward; von Wilmowsky, Cornelius; Neuhuber, Winfried; Lell, Michael; Neukam, Friedrich W; Adler, Werner; Wichmann, Manfred; Bergauer, Bastian

2016-05-01

Multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT) are indispensable imaging techniques in advanced medicine. The possibility of creating virtual and corporal three-dimensional (3D) models enables detailed planning in craniofacial and oral surgery. The objective of this study was to evaluate the impact of different scan protocols for CBCT and MSCT on virtual 3D model accuracy using a software-based evaluation method that excludes human measurement errors. MSCT and CBCT scans with different manufacturers' predefined scan protocols were obtained from a human lower jaw and were superimposed with a master model generated by an optical scan of an industrial noncontact scanner. To determine the accuracy, the mean and standard deviations were calculated, and t-tests were used for comparisons between the different settings. Averaged over 10 repeated X-ray scans per method and 19 measurement points per scan (n = 190), it was found that the MSCT scan protocol 140 kV delivered the most accurate virtual 3D model, with a mean deviation of 0.106 mm compared to the master model. Only the CBCT scans with 0.2-voxel resolution delivered a similar accurate 3D model (mean deviation 0.119 mm). Within the limitations of this study, it was demonstrated that the accuracy of a 3D model of the lower jaw depends on the protocol used for MSCT and CBCT scans. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Abdominal CT scan

MedlinePlus

Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... An abdominal CT scan makes detailed pictures of the structures inside your belly very quickly. This test may be used to look ...

Technical Considerations on Scanning and Image Analysis for Amyloid PET in Dementia.

PubMed

Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Yamamoto, Yasuji; Senda, Michio

2017-01-01

Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice.

Fluorescent scanning x-ray tomography with synchrotron radiation

NASA Astrophysics Data System (ADS)

Takeda, Tohoru; Maeda, Toshikazu; Yuasa, Tetsuya; Akatsuka, Takao; Ito, Tatsuo; Kishi, Kenichi; Wu, Jin; Kazama, Masahiro; Hyodo, Kazuyuki; Itai, Yuji

1995-02-01

Fluorescent scanning (FS) x-ray tomography was developed to detect nonradioactive tracer materials (iodine and gadolinium) in a living object. FS x-ray tomography consists of a silicon (111) channel cut monochromator, an x-ray shutter, an x-ray slit system and a collimator for detection, a scanning table for the target organ, and an x-ray detector with pure germanium. The minimal detectable dose of iodine in this experiment was 100 ng in a volume of 2 mm3 and a linear relationship was shown between the photon counts of a fluorescent x ray and the concentration of iodine contrast material. A FS x-ray tomographic image was clearly obtained with a phantom.

Cervical spine CT scan

MedlinePlus

... cervical spine; Computed tomography scan of cervical spine; CT scan of cervical spine; Neck CT scan ... table that slides into the center of the CT scanner. Once you are inside the scanner, the ...

Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro

2016-01-28

Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.

Minimally invasive repair of pectus excavatum (MIRPE)--the Basel experience.

PubMed

Haecker, F M; Bielek, J; von Schweinitz, D

2003-01-01

Minimally invasive repair of pectus excavatum (MIRPE) was first reported in 1998 by D. Nuss. This technique has gained wide acceptance during the last 4-5 years. In the meantime, some modifications of the technique have been introduced by different authors. Our retrospective study reports our own experience over the last 36 months and modifications introduced due to a number of complications. From 3/2000 to 3/2003, 22 patients underwent MIRPE. Patients median age was 15.5 years (10.7 to 20.3 years). Standardised preoperative evaluation included 3D computerised tomography (CT) scan, pulmonary function tests, cardiac evaluation with electrocardiogram and echocardiography, and photo documentation. Indications for operation included at least two of the following: Haller CT index > 3.2, restrictive lung disease, cardiac compression, progression of the deformity and severe psychological alterations. In 22 patients (2 girls, 20 boys) undergoing MIRPE procedure, a single bar was used in 21 patients and two bars in one boy. Lateral stabilisers were fixed with non resorbable sutures on both sides. Overall, postoperative complications occurred in six patients (27.3%). In two patients (9.1%) a redo-procedure was necessary due to bar displacement. An additional median skin incision was performed in two patients to elevate the sternum. Pneumothorax or hematothorax in two patients resulted in routine use of a chest tube on both sides. Long-term favourable results were noted in all patients. The MIRPE procedure is an effective method with elegant cosmetic results. Modifications of the original method help to decrease the complication rate and to accelerate acquirement of expertise.

Malignant external otitis: the role of computed tomography and radionuclides in evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendelson, D.S.; Som, P.M.; Mendelson, M.H.

1983-12-01

Nine patients with malignant external otitis (MEO) were evaluated with Tc-99m bone scans, Ga-67 citrate scans, pluridirectional tomography, and computed tomographic (CT) scans in order to assess the role of each in the diagnosis and management of MEO. The Tc-99m and Ga-67 citrate scans were the most accurate studies in the initial identification of disease activity, while the return to normal or improvement of the Ga-67 citrate scan has been shown to correlate best with clinical resolution of MEO. CT demonstrated soft-tissue disease and central skull base osteomyelitis better than pluridirectional tomography. CT is excellent for localizing and following themore » progression of bone disease; however, because reossification of the skull base is a very slow process, CT cannot be used to follow accurately regression or inactivity of MEO affecting this area. CT is the best modality for following soft-tissue extension of MEO.« less

[The electronic health record: computerised provider order entry and the electronic instruction document as new functionalities].

PubMed

Derikx, Joep P M; Erdkamp, Frans L G; Hoofwijk, A G M

2013-01-01

An electronic health record (EHR) should provide 4 key functionalities: (a) documenting patient data; (b) facilitating computerised provider order entry; (c) displaying the results of diagnostic research; and (d) providing support for healthcare providers in the clinical decision-making process.- Computerised provider order entry into the EHR enables the electronic receipt and transfer of orders to ancillary departments, which can take the place of handwritten orders.- By classifying the computer provider order entries according to disorders, digital care pathways can be created. Such care pathways could result in faster and improved diagnostics.- Communicating by means of an electronic instruction document that is linked to a computerised provider order entry facilitates the provision of healthcare in a safer, more efficient and auditable manner.- The implementation of a full-scale EHR has been delayed as a result of economic, technical and legal barriers, as well as some resistance by physicians.

Single-shot ultrafast tomographic imaging by spectral multiplexing

NASA Astrophysics Data System (ADS)

Matlis, N. H.; Axley, A.; Leemans, W. P.

2012-10-01

Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

Transmission of Hepatitis C Virus during Computed Tomography Scanning with Contrast

PubMed Central

Rius, Cristina; Caylà, Joan A.

2008-01-01

Six cases of acute hepatitis C related to computed tomography scanning with contrast were identified in 3 hospitals. A patient with chronic hepatitis C had been subjected to the same procedure immediately before each patient who developed acute infection. Viral molecular analysis showed identity between isolates from cases with acute and chronic hepatitis C. PMID:18258135

Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal

2016-03-21

X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematicmore » investigation of complex samples containing both soft and hard materials.« less

Cholangiocarcinoma associated with limbic encephalitis and early cerebral abnormalities detected by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography: a case report.

PubMed

Schmidt, Sergio L; Schmidt, Juliana J; Tolentino, Julio C; Ferreira, Carlos G; de Almeida, Sergio A; Alvarenga, Regina P; Simoes, Eunice N; Schmidt, Guilherme J; Canedo, Nathalie H S; Chimelli, Leila

2016-07-20

Limbic encephalitis was originally described as a rare clinical neuropathological entity involving seizures and neuropsychological disturbances. In this report, we describe cerebral patterns visualized by positron emission tomography in a patient with limbic encephalitis and cholangiocarcinoma. To our knowledge, there is no other description in the literature of cerebral positron emission tomography findings in the setting of limbic encephalitis and subsequent diagnosis of cholangiocarcinoma. We describe a case of a 77-year-old Caucasian man who exhibited persistent cognitive changes 2 years before his death. A cerebral scan obtained at that time by 2-deoxy-2-[fluorine-18]fluoro- D -glucose integrated with computed tomography-positron emission tomography showed low radiotracer uptake in the frontal and temporal lobes. Cerebrospinal fluid analysis indicated the presence of voltage-gated potassium channel antibodies. Three months before the patient's death, a lymph node biopsy indicated a cholangiocarcinoma, and a new cerebral scan obtained by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography showed an increment in the severity of metabolic deficit in the frontal and parietal lobes, as well as hypometabolism involving the temporal lobes. Two months before the patient's death, cerebral metastases were detected on a contrast-enhanced computed tomographic scan. Postmortem examination revealed a cholangiocarcinoma with multiple metastases including the lungs and lymph nodes. The patient's brain weighed 1300 g, and mild cortical atrophy, ex vacuo dilation of the ventricles, and mild focal thickening of the cerebellar leptomeninges, which were infiltrated by neoplastic epithelial cells, were observed. These findings support the need for continued vigilance in malignancy surveillance in patients with limbic encephalitis and early cerebral positron emission tomographic scan abnormalities. The difficulty in early diagnosis of small tumors, such as a cholangiocarcinoma, is discussed in the context of the clinical utility of early cerebral hypometabolism detected by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography in patients with rapidly progressive dementia.

Barium Sulfate

MedlinePlus

... and intestine using x-rays or computed tomography (CAT scan, CT scan; a type of body scan that uses a ... be clearly seen by x-ray examination or CT scan. ... more times before an x-ray examination or CT scan.If you are using a barium sulfate enema, ...

Breast ultrasound tomography with two parallel transducer arrays

NASA Astrophysics Data System (ADS)

Huang, Lianjie; Shin, Junseob; Chen, Ting; Lin, Youzuo; Gao, Kai; Intrator, Miranda; Hanson, Kenneth

2016-03-01

Breast ultrasound tomography is an emerging imaging modality to reconstruct the sound speed, density, and ultrasound attenuation of the breast in addition to ultrasound reflection/beamforming images for breast cancer detection and characterization. We recently designed and manufactured a new synthetic-aperture breast ultrasound tomography prototype with two parallel transducer arrays consisting of a total of 768 transducer elements. The transducer arrays are translated vertically to scan the breast in a warm water tank from the chest wall/axillary region to the nipple region to acquire ultrasound transmission and reflection data for whole-breast ultrasound tomography imaging. The distance of these two ultrasound transducer arrays is adjustable for scanning breasts with different sizes. We use our breast ultrasound tomography prototype to acquire phantom and in vivo patient ultrasound data to study its feasibility for breast imaging. We apply our recently developed ultrasound imaging and tomography algorithms to ultrasound data acquired using our breast ultrasound tomography system. Our in vivo patient imaging results demonstrate that our breast ultrasound tomography can detect breast lesions shown on clinical ultrasound and mammographic images.

CT scan

MedlinePlus

... this page: //medlineplus.gov/ency/article/003330.htm CT scan To use the sharing features on this page, please enable JavaScript. A computed tomography (CT) scan is an imaging method that uses x- ...

Beam hardening correction for interior tomography based on exponential formed model and radon inversion transform

NASA Astrophysics Data System (ADS)

Chen, Siyu; Zhang, Hanming; Li, Lei; Xi, Xiaoqi; Han, Yu; Yan, Bin

2016-10-01

X-ray computed tomography (CT) has been extensively applied in industrial non-destructive testing (NDT). However, in practical applications, the X-ray beam polychromaticity often results in beam hardening problems for image reconstruction. The beam hardening artifacts, which manifested as cupping, streaks and flares, not only debase the image quality, but also disturb the subsequent analyses. Unfortunately, conventional CT scanning requires that the scanned object is completely covered by the field of view (FOV), the state-of-art beam hardening correction methods only consider the ideal scanning configuration, and often suffer problems for interior tomography due to the projection truncation. Aiming at this problem, this paper proposed a beam hardening correction method based on radon inversion transform for interior tomography. Experimental results show that, compared to the conventional correction algorithms, the proposed approach has achieved excellent performance in both beam hardening artifacts reduction and truncation artifacts suppression. Therefore, the presented method has vitally theoretic and practicable meaning in artifacts correction of industrial CT.

Interlaced X-ray diffraction computed tomography

PubMed Central

Vamvakeros, Antonios; Jacques, Simon D. M.; Di Michiel, Marco; Senecal, Pierre; Middelkoop, Vesna; Cernik, Robert J.; Beale, Andrew M.

2016-01-01

An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn–Na–W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy. PMID:27047305

Applying Adaptive Variables in Computerised Adaptive Testing

ERIC Educational Resources Information Center

Triantafillou, Evangelos; Georgiadou, Elissavet; Economides, Anastasios A.

2007-01-01

Current research in computerised adaptive testing (CAT) focuses on applications, in small and large scale, that address self assessment, training, employment, teacher professional development for schools, industry, military, assessment of non-cognitive skills, etc. Dynamic item generation tools and automated scoring of complex, constructed…

Two-phase computed tomography study of warthin tumor of parotid gland: differentiation from other parotid gland tumors and its pathologic explanation.

PubMed

Woo, Seung Hoon; Choi, Dae-Seob; Kim, Jin-pyeong; Park, Jung Je; Joo, Yeon Hee; Chung, Phil-Sang; Kim, Bo-Young; Ko, Young-Hyeh; Jeong, Han-Sin; Kim, Hyung-Jin

2013-01-01

The objective of this study was to define the radiological characteristics of 2-phase computed tomography (CT) of parotid gland Warthin tumors (WTs) with a pathologic basis for these findings. We prospectively enrolled 116 patients with parotid gland tumor who underwent preoperative 2-phase CT scans(scanning delays of 30 and 120 seconds). The attenuation changes and enhancement patterns were analyzed according to pathology. We also evaluated size-matched samples of WTs and pleomorphic adenoma by staining CD31, vascular endothelial growth factor-receptor 2, collagen IV, and smooth muscle actin. Computed tomography numbers in WTs were significantly higher than those in other tumors in early-phase scans and lower in delayed scans. Pathologically, CD31(+) blood vessel area was significantly higher in WTs than in pleomorphic adenomas. In addition, WTs had an extensive capillary network and many leaky blood vessels. The enhancement pattern of early fill-in and early washout is the typical finding of WTs on 2-phase CT scans, which may be attributed pathologically to abundant blood vessel and extensive capillary network.

Computerised interventions designed to reduce potentially inappropriate prescribing in hospitalised older adults: a systematic review and meta-analysis.

PubMed

Dalton, Kieran; O'Brien, Gary; O'Mahony, Denis; Byrne, Stephen

2018-06-08

computerised interventions have been suggested as an effective strategy to reduce potentially inappropriate prescribing (PIP) for hospitalised older adults. This systematic review and meta-analysis examined the evidence for efficacy of computerised interventions designed to reduce PIP in this patient group. an electronic literature search was conducted using eight databases up to October 2017. Included studies were controlled trials of computerised interventions aiming to reduce PIP in hospitalised older adults (≥65 years). Risk of bias was assessed using Cochrane's Effective Practice and Organisation of Care criteria. of 653 records identified, eight studies were included-two randomised controlled trials, two interrupted time series analysis studies and four controlled before-after studies. Included studies were mostly at a low risk of bias. Overall, seven studies showed either a statistically significant reduction in the proportion of patients prescribed a potentially inappropriate medicine (PIM) (absolute risk reduction {ARR} 1.3-30.1%), or in PIMs ordered (ARR 2-5.9%). However, there is insufficient evidence thus far to suggest that these interventions can routinely improve patient-related outcomes. It was only possible to include three studies in the meta-analysis-which demonstrated that intervention patients were less likely to be prescribed a PIM (odds ratio 0.6; 95% CI 0.38, 0.93). No computerised intervention targeting potential prescribing omissions (PPOs) was identified. this systematic review concludes that computerised interventions are capable of statistically significantly reducing PIMs in hospitalised older adults. Future interventions should strive to target both PIMs and PPOs, ideally demonstrating both cost-effectiveness data and clinically significant improvements in patient-related outcomes.

Three-dimensional imaging of adherent cells using FIB/SEM and STEM.

PubMed

Villinger, Clarissa; Schauflinger, Martin; Gregorius, Heiko; Kranz, Christine; Höhn, Katharina; Nafeey, Soufi; Walther, Paul

2014-01-01

In this chapter we describe three different approaches for three-dimensional imaging of electron microscopic samples: serial sectioning transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) tomography, and focused ion beam/scanning electron microscopy (FIB/SEM) tomography. With these methods, relatively large volumes of resin-embedded biological structures can be analyzed at resolutions of a few nm within a reasonable expenditure of time. The traditional method is serial sectioning and imaging the same area in all sections. Another method is TEM tomography that involves tilting a section in the electron beam and then reconstruction of the volume by back projection of the images. When the scanning transmission (STEM) mode is used, thicker sections (up to 1 μm) can be analyzed. The third approach presented here is focused ion beam/scanning electron microscopy (FIB/SEM) tomography, in which a sample is repeatedly milled with a focused ion beam (FIB) and each newly produced block face is imaged with the scanning electron microscope (SEM). This process can be repeated ad libitum in arbitrary small increments allowing 3D analysis of relatively large volumes such as eukaryotic cells. We show that resolution of this approach is considerably improved when the secondary electron signal is used. However, the most important prerequisite for three-dimensional imaging is good specimen preparation. For all three imaging methods, cryo-fixed (high-pressure frozen) and freeze-substituted samples have been used.

MEMS scanning micromirror for optical coherence tomography.

PubMed

Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y

2015-01-01

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique.

MEMS scanning micromirror for optical coherence tomography

PubMed Central

Strathman, Matthew; Liu, Yunbo; Keeler, Ethan G.; Song, Mingli; Baran, Utku; Xi, Jiefeng; Sun, Ming-Ting; Wang, Ruikang; Li, Xingde; Lin, Lih Y.

2014-01-01

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique. PMID:25657887

Computed tomography of infantile hepatic hemangioendothelioma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucaya, J.; Enriquez, G.; Amat, L.

1985-04-01

Computed tomography (CT) was performed on five infants with hepatic hemangioendothelioma. Precontrast scans showed solitary or multiple, homogeneous, circumscribed areas with reduced attenuation values. Tiny tumoral calcifications were identified in two patients. Serial scans, after injection of a bolus of contrast material, showed early massive enhancement, which was either diffuse or peripheral. On delayed scans, multinocular tumors became isodense with surrounding liver, while all solitary ones showed varied degrees of centripetal enhancement and persistent central cleftlike unenhanced areas. The authors believe that these CT features are characteristic and obviate arteriographic confirmation.

Infrared scanning laser ophthalmoscope imaging of the macula and its correlation with functional loss and structural changes in patients with stargardt disease.

PubMed

Anastasakis, Anastasios; Fishman, Gerald A; Lindeman, Martin; Genead, Mohamed A; Zhou, Wensheng

2011-05-01

To correlate the degree of functional loss with structural changes in patients with Stargardt disease. Eighteen eyes of 10 patients with Stargardt disease were studied. Scanning laser ophthalmoscope infrared images were compared with corresponding spectral-domain optical coherence tomography scans. Additionally, scanning laser ophthalmoscope microperimetry was performed, and results were superimposed on scanning laser ophthalmoscope infrared images and in selected cases on fundus autofluorescence images. Seventeen of 18 eyes showed a distinct hyporeflective foveal and/or perifoveal area with distinct borders on scanning laser ophthalmoscope infrared images, which was less evident on funduscopy and incompletely depicted in fundus autofluorescence images. This hyporeflective zone corresponded to areas of significantly elevated psychophysical thresholds on microperimetry testing, in addition to thinning of the retinal pigment epithelium and disorganization or loss of the photoreceptor cell inner segment-outer segment junction and external-limiting membrane on spectral-domain optical coherence tomography. Scanning laser ophthalmoscope infrared fundus images are useful for depicting retinal structural changes in patients with Stargardt disease. A spectral-domain optical coherence tomography/scanning laser ophthalmoscope microperimetry device allows for a direct correlation of structural abnormalities with functional defects that will likely be applicable for the determination of retinal areas for potential improvement of retinal function in these patients during future clinical trials and for the monitoring of the diseases' natural history.

Use of Reference Ear Plug to improve accuracy of lateral cephalograms generated from cone-beam computed tomography scans

PubMed Central

Lee, Kyung-Min; Uhm, Gi-Soo; Cho, Jin-Hyoung; McNamara, James A.

2013-01-01

Objective The purpose of this study was to evaluate the effectiveness of the use of Reference Ear Plug (REP) during cone-beam computed tomography (CBCT) scan for the generation of lateral cephalograms from CBCT scan data. Methods Two CBCT scans were obtained from 33 adults. One CBCT scan was acquired using conventional methods, and the other scan was acquired with the use of REP. Virtual lateral cephalograms created from each CBCT image were traced and compared with tracings of the real cephalograms obtained from the same subject. Results CBCT scan with REP resulted in a smaller discrepancy between real and virtual cephalograms. In comparing the real and virtual cephalograms, no measurements significantly differed from real cephalogram values in case of CBCT scan with REP, whereas many measurements significantly differed in the case of CBCT scan without REP. Conclusion Measurements from CBCT-generated cephalograms are more similar to those from real cephalograms when REP are used during CBCT scan. Thus, the use of REP is suggested during CBCT scan to generate accurate virtual cephalograms from CBCT scan data. PMID:23671830

Advancing beyond the system: telemedicine nurses' clinical reasoning using a computerised decision support system for patients with COPD - an ethnographic study.

PubMed

Barken, Tina Lien; Thygesen, Elin; Söderhamn, Ulrika

2017-12-28

Telemedicine is changing traditional nursing care, and entails nurses performing advanced and complex care within a new clinical environment, and monitoring patients at a distance. Telemedicine practice requires complex disease management, advocating that the nurses' reasoning and decision-making processes are supported. Computerised decision support systems are being used increasingly to assist reasoning and decision-making in different situations. However, little research has focused on the clinical reasoning of nurses using a computerised decision support system in a telemedicine setting. Therefore, the objective of the study is to explore the process of telemedicine nurses' clinical reasoning when using a computerised decision support system for the management of patients with chronic obstructive pulmonary disease. The factors influencing the reasoning and decision-making processes were investigated. In this ethnographic study, a combination of data collection methods, including participatory observations, the think-aloud technique, and a focus group interview was employed. Collected data were analysed using qualitative content analysis. When telemedicine nurses used a computerised decision support system for the management of patients with complex, unstable chronic obstructive pulmonary disease, two categories emerged: "the process of telemedicine nurses' reasoning to assess health change" and "the influence of the telemedicine setting on nurses' reasoning and decision-making processes". An overall theme, termed "advancing beyond the system", represented the connection between the reasoning processes and the telemedicine work and setting, where being familiar with the patient functioned as a foundation for the nurses' clinical reasoning process. In the telemedicine setting, when supported by a computerised decision support system, nurses' reasoning was enabled by the continuous flow of digital clinical data, regular video-mediated contact and shared decision-making with the patient. These factors fostered an in-depth knowledge of the patients and acted as a foundation for the nurses' reasoning process. Nurses' reasoning frequently advanced beyond the computerised decision support system recommendations. Future studies are warranted to develop more accurate algorithms, increase system maturity, and improve the integration of the digital clinical information with clinical experiences, to support telemedicine nurses' reasoning process.

Melorheostosis associated with peripheral form spondyloarthropathy: new image with 18-fluoride positron emission tomoscintigraphy coupled to computed tomography

PubMed Central

Hassani, Hakim; Slama, Jérôme; Hayem, Gilles; Ben Ali, Khadija; Sarda-Mantel, Laure; Burg, Samuel; Le Guludec, Dominique

2012-01-01

Melorheostosis is a rare benign bone pathology which can be responsible for incapacitating pain and bone deformations. Its imaging abnormalities are often typical. We describe here the case of a patient with melorheostosis involving the lower limbs, associated with a peripheral form of inflammatory spondyloarthropathy, who underwent 18FNa positron emission tomography coupled to a computed tomography scan. Our objective is to present this new image, to show the value of this new modality and emphasize its advantages compared to the 99mTechnetium bone scan. PMID:27790007

[Evaluation of the depth of infiltration of urothelial carcinoma in the vesical wall obtained by transurethral intravesical echotomography].

PubMed

Milosević, Radovan; Milović, Novak; Stijelja, Borislav; Dokić, Milan; Campara, Zoran; Mocović, Dejan

2007-10-01

Transitional cell carcinoma (TCC) is the most frequent tumor of the bladder and represents 95-98% of blader neoplasams and 2-3% of all carcinomas in the body. In urogenital oncology more frequent is only prostatic cancer. Evaluation of the depth of infiltration of urothelial carcinoma in the vesical wall represents the clinical base in treatment planning and prognosis. Clinical investigation and convential radiological procedures have a low level of accuracy in estimating the local growth of the tumor. The aims of our investigation were to determine the depth of infiltration of urothelial carcinoma in the vesical wall in the investigated group of patients by transurethral intravesical echotomography (TIE) and computerised tomography (CT scan) and to compare results obtained by both methods with pathohistological (PH) results, and, based on the difference of the results determine which method was more accurate in the evaluation of the depth of infiltration of urothelial carcinoma in the vesical wall. Thirty patients with TCC of the bladder both genders, aged 51-81 years were involved in our investigation. In all of these patients, radical cystectomy (RC) was performed. This was neccessary to provide the defintive PH result. Transurethral intravesical echotomography was performed by ultrasound scanner type 1846 Bruel and Kjaer, sond type 1850, and the CT scan was perfomed by Pace plus, General Electric, U.S.A. The specimen for the definitive PH result obtained by RC includes all standards of the TNM classification. Using CT scan, the most frequent was T1 stage (17 patients or 56.68%). Using TIE, the most frequent was T2 stage (22 patients or 73.33%). After RC the most frequent was T2 stage (21 patients or 70%). The Kolmogorov-Smirnov test, showed a high significant difference between the results obtained using CT and definitive PH results after RC. The same test showed no statistically significant difference between the results obtained using TIE and definitive PH results. The sensitivity and accurance of TIE compared to definitive PH results was 93.3%, but using CT it was only 33.3%. There was a significant difference between the results obtained using CT and TIE. The results obtained by TIE were in closer relation with the definitive PH results than the results obtained by CT scan. TIE provides more precise evaluation of the depth of infiltration of urothelial carcinoma in the vesical wall than CT scan. We conclude that the use of this procedure in local staging in TCC is justified and represents the clinical basis in the treatment planning and disease outcome prognosis.

Sinonasal papilloma: what influences the decision to request a magnetic resonance imaging scan?

PubMed

Kasbekar, A V; Swords, C; Attlmayr, B; Kulkarni, T; Swift, A C

2018-06-18

Computed tomography is the standard pre-operative imaging modality for sinonasal papilloma. The complementary use of magnetic resonance imaging as an additional investigation is debated. This study aimed to establish whether magnetic resonance imaging can accurately detect tumour extent and is a useful adjunct to computed tomography. A retrospective review was conducted on 19 patients with sinonasal papilloma. The interpretation of computed tomography and magnetic resonance imaging scans, by three clinicians, was conducted by comparing prediction of tumour extent. The perceived necessity of magnetic resonance imaging was compared between clinicians. The addition of magnetic resonance imaging improved accuracy of pre-operative interpretation; specifically, this finding was significant in cases with frontal sinus involvement. Surgeons were more likely than a radiologist to request magnetic resonance imaging, particularly when computed tomography indicated frontal sinus disease. Pre-operative combined magnetic resonance imaging and computed tomography helped predict disease in the frontal sinus better than computed tomography alone. A close working relationship between the ENT and radiology departments is important for accurate tumour localisation.

Three-dimensional surface reconstruction for industrial computed tomography

NASA Technical Reports Server (NTRS)

Vannier, M. W.; Knapp, R. H.; Gayou, D. E.; Sammon, N. P.; Butterfield, R. L.; Larson, J. W.

1985-01-01

Modern high resolution medical computed tomography (CT) scanners can produce geometrically accurate sectional images of many types of industrial objects. Computer software has been developed to convert serial CT scans into a three-dimensional surface form, suitable for display on the scanner itself. This software, originally developed for imaging the skull, has been adapted for application to industrial CT scanning, where serial CT scans thrrough an object of interest may be reconstructed to demonstrate spatial relationships in three dimensions that cannot be easily understood using the original slices. The methods of three-dimensional reconstruction and solid modeling are reviewed, and reconstruction in three dimensions from CT scans through familiar objects is demonstrated.

PET-NECK: a multicentre randomised Phase III non-inferiority trial comparing a positron emission tomography-computerised tomography-guided watch-and-wait policy with planned neck dissection in the management of locally advanced (N2/N3) nodal metastases in patients with squamous cell head and neck cancer.

PubMed

Mehanna, Hisham; McConkey, Chris C; Rahman, Joy K; Wong, Wai-Lup; Smith, Alison F; Nutting, Chris; Hartley, Andrew Gj; Hall, Peter; Hulme, Claire; Patel, Dharmesh K; Zeidler, Sandra Ventorin von; Robinson, Max; Sanghera, Bal; Fresco, Lydia; Dunn, Janet A

2017-04-01

Planned neck dissection (ND) after radical chemoradiotherapy (CRT) for locally advanced nodal metastases in patients with head and neck squamous cell carcinoma (HNSCC) remains controversial. Thirty per cent of ND specimens show histological evidence of tumour. Consequently, a significant proportion of clinicians still practise planned ND. Fludeoxyglucose positron emission tomography (PET)-computerised tomography (CT) scanning demonstrated high negative predictive values for persistent nodal disease, providing a possible alternative paradigm to ND. Evidence is sparse and drawn mainly from retrospective single-institution studies, illustrating the need for a prospective randomised controlled trial. To determine the efficacy and cost-effectiveness of PET-CT-guided surveillance, compared with planned ND, in a multicentre, prospective, randomised setting. A pragmatic randomised non-inferiority trial comparing PET-CT-guided watch-and-wait policy with the current planned ND policy in HNSCC patients with locally advanced nodal metastases and treated with radical CRT. Patients were randomised in a 1 : 1 ratio. Primary outcomes were overall survival (OS) and cost-effectiveness [incremental cost per incremental quality-adjusted life-year (QALY)]. Cost-effectiveness was assessed over the trial period using individual patient data, and over a lifetime horizon using a decision-analytic model. Secondary outcomes were recurrence in the neck, complication rates and quality of life. The recruitment of 560 patients was planned to detect non-inferior OS in the intervention arm with a 90% power and a type I error of 5%, with non-inferiority defined as having a hazard ratio (HR) of no higher than 1.50. An intention-to-treat analysis was performed by Cox's proportional hazards model. Thirty-seven head and neck cancer-treating centres (43 NHS hospitals) throughout the UK. Patients with locally advanced nodal metastases of oropharynx, hypopharynx, larynx, oral or occult HNSCC receiving CRT and fit for ND were recruited. Patients randomised to planned ND before or after CRT (control), or CRT followed by fludeoxyglucose PET-CT 10-12 weeks post CRT with ND only if PET-CT showed incomplete or equivocal response of nodal disease (intervention). Balanced by centre, planned ND timing, CRT schedule, disease site and the tumour, node, metastasis stage. In total, 564 patients were recruited (ND arm, n  = 282; and surveillance arm, n  = 282; 17% N2a, 61% N2b, 18% N2c and 3% N3). Eighty-four per cent had oropharyngeal cancer. Seventy-five per cent of tested cases were p16 positive. The median time to follow-up was 36 months. The HR for OS was 0.92 [95% confidence interval (CI) 0.65 to 1.32], indicating non-inferiority. The upper limit of the non-inferiority HR margin of 1.50, which was informed by patient advisors to the project, lies at the 99.6 percentile of this estimate ( p  = 0.004). There were no differences in this result by p16 status. There were 54 NDs performed in the surveillance arm, with 22 surgical complications, and 221 NDs in the ND arm, with 85 complications. Quality-of-life scores were slightly better in the surveillance arm. Compared with planned ND, PET-CT surveillance produced an incremental net health benefit of 0.16 QALYs (95% CI 0.03 to 0.28 QALYs) over the trial period and 0.21 QALYs (95% CI -0.41 to 0.85 QALYs) over the modelled lifetime horizon. Pragmatic randomised controlled trial with a 36-month median follow-up. PET-CT-guided active surveillance showed similar survival outcomes to ND but resulted in considerably fewer NDs, fewer complications and lower costs, supporting its use in routine practice. PET-CT surveillance is cost-effective in the short term, and long-term cost-effectiveness could be addressed in future work. Current Controlled Trials ISRCTN13735240. This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 21, No. 17. See the NIHR Journals Library website for further project information.

TOWARD QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: Visualizing Blood Flow Speeds in Ocular Pathology Using Variable Interscan Time Analysis.

PubMed

Ploner, Stefan B; Moult, Eric M; Choi, WooJhon; Waheed, Nadia K; Lee, ByungKun; Novais, Eduardo A; Cole, Emily D; Potsaid, Benjamin; Husvogt, Lennart; Schottenhamml, Julia; Maier, Andreas; Rosenfeld, Philip J; Duker, Jay S; Hornegger, Joachim; Fujimoto, James G

2016-12-01

Currently available optical coherence tomography angiography systems provide information about blood flux but only limited information about blood flow speed. The authors develop a method for mapping the previously proposed variable interscan time analysis (VISTA) algorithm into a color display that encodes relative blood flow speed. Optical coherence tomography angiography was performed with a 1,050 nm, 400 kHz A-scan rate, swept source optical coherence tomography system using a 5 repeated B-scan protocol. Variable interscan time analysis was used to compute the optical coherence tomography angiography signal from B-scan pairs having 1.5 millisecond and 3.0 milliseconds interscan times. The resulting VISTA data were then mapped to a color space for display. The authors evaluated the VISTA visualization algorithm in normal eyes (n = 2), nonproliferative diabetic retinopathy eyes (n = 6), proliferative diabetic retinopathy eyes (n = 3), geographic atrophy eyes (n = 4), and exudative age-related macular degeneration eyes (n = 2). All eyes showed blood flow speed variations, and all eyes with pathology showed abnormal blood flow speeds compared with controls. The authors developed a novel method for mapping VISTA into a color display, allowing visualization of relative blood flow speeds. The method was found useful, in a small case series, for visualizing blood flow speeds in a variety of ocular diseases and serves as a step toward quantitative optical coherence tomography angiography.

Computerised Attention Training for Children with Intellectual and Developmental Disabilities: A Randomised Controlled Trial

ERIC Educational Resources Information Center

Kirk, Hannah E.; Gray, Kylie M.; Ellis, Kirsten; Taffe, John; Cornish, Kim M.

2016-01-01

Background: Children with intellectual and developmental disabilities (IDD) experience heightened attention difficulties which have been linked to poorer cognitive, academic and social outcomes. Although, increasing research has focused on the potential of computerised cognitive training in reducing attention problems, limited studies have…

Positron Emission Tomography (PET) and Positron Scanning

Science.gov Websites

National Laboratory 'Positron Emission Tomography ... [is a medical imaging technique that] can track human brain.' Edited excerpts from from Medical Applications of Non-Medical Research: Applications Technical Report, November 1988 High-resolution PET (Positron Emission Tomography) for Medical Science

Passively Driven Probe Based on Miniaturized Propeller for Intravascular Optical Coherence Tomography.

PubMed

Lu, Yu; Li, Zhongliang; Nan, Nan; Bu, Yang; Liu, Xuebo; Xu, Xiangdong; Wang, Xuan; Sasaki, Osami; Wang, Xiangzhao

2018-03-26

Optical coherent tomography (OCT) has enabled clinical applications ranging from ophthalmology to cardiology that revolutionized in vivo medical diagnostics in the last few decades, and a variety of endoscopic probes have been developed in order to meet the needs of various endoscopic OCT imaging. We propose a passive driven intravascular optical coherent tomography (IV-OCT) probe in this paper. Instead of using any electrically driven scanning device, the probe makes use of the kinetic energy of the fluid that flushes away the blood during the intravascular optical coherence tomography imaging. The probe converts it into the rotational kinetic energy of the propeller, and the rotation of the rectangular prism mounted on the propeller shaft enables the scanning of the beam. The probe is low cost, and enables unobstructed stable circumferential scanning over 360 deg. The experimental results show that the probe scanning speed can exceed 100 rotations per second (rps). Spectral-domain OCT imaging of a phantom and porcine cardiac artery are demonstrated with axial resolution of 13.6 μm, lateral resolution of 22 μm, and sensitivity of 101.7 dB. We present technically the passively driven IV-OCT probe in full detail and discuss how to optimize the probe in further.

6 Mcps photon-counting X-ray computed tomography system using a 25 mm/s-scan linear LSO-MPPC detector and its application to gadolinium imaging

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-12-01

6 Mcps photon counting was carried out using a detector consisting of a 1.0 mm-thick LSO [Lu 2(SiO 4)O] single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 6 Mcps (mega counts per second) at a tube voltage of 100 kV and a tube current of 0.91 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the LSO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using gadolinium-based contrast media.

In vivo determination of a modified heat capacity of small hepatocellular carcinomas prior to radiofrequency ablation: correlation with adjacent vasculature and tumour recurrence.

PubMed

Sheiman, Robert G; Mullan, Charles; Ahmed, Muneeb

2012-01-01

To calculate a modified heat capacity (mHC) of small hepatocellular carcinomas (HCCs) in vivo during radio frequency ablation (RFA) and to determine if mHC correlates with tumour vascularity, adjacent vessels or local recurrence. This study was IRB approved and informed consent was obtained from all patients. Before formal RFA, ambient HCC temperature and temperature 1 min after heating at constant wattage were measured in 29 patients. From temperature change and wattage, individual mHCs (joules required to increase tumour temperature by 1° Celsius) were calculated. Pre-RFA, three-phase computerised tomography (CT) scans were reviewed blindly for hepatic arteries, hepatic veins and portal veins abutting or within 3 mm of tumour edge from which twelve vascular parameters were quantified. Tumour enhancement (homogeneous or heterogeneous on arterial phase) was also assessed. Multiple regression was used to correlate mHC with vascular parameters and tumour enhancement. Cox proportional hazard model was used to examine the relationship of mHC to local recurrence. There was significant correlation of mHC with lesion enhancement (P = 0.0018), length of hepatic arteries (P < 0.0001) and total hepatic vein volume in contact with tumour (P = 0.016). No correlation was found with any non-abutting vessel or portal vein parameter. The chance of local recurrence increased with increasing mHC. Because the modified heat capacity of small HCCs in our study population correlated with HCC enhancement, abutting hepatic arteries, the volume of abutting hepatic veins and local recurrence, it may be an indicator of the heat sink effect (HSE) and supports the HSE as a risk factor for local recurrence.

A headache not to be sneezed at.

PubMed

Garry, D; Forrest-Hay, A

2009-05-01

A 32-year-old male patient presented to the emergency department (ED) complaining of a headache and vertigo precipitated by sneezing. He had a recent history of neck trauma. Examination revealed horizontal nystagmus and a gait that veered to the left, exacerbated by heel to toe walking. A diagnosis of vertebral artery dissection (VAD) was suspected. A bleed was ruled out in the ED by computerised tomography, after which the patient was loaded with aspirin. The diagnosis was confirmed by magnetic resonance imaging and magnetic resonance angiography. Although optimal treatment for VAD is unknown, the Cervical Artery Dissection in Stroke Study (CADISS) is an ongoing randomised multicentre prospective study comparing antiplatelet therapy with anticoagulation for patients with both carotid artery dissection and VAD. Headache is a very common presentation to the ED and a full neurological examination is essential if rarer causes are not to be missed.

Lesson of the month 1: Lobar pulmonary consolidation in an immunocompromised host.

PubMed

Reynolds, Daniel J; Andersen, Carl A; Hoskote, Sumedh S; Lee, Hee Eun; Raghunathan, Aditya; Kalra, Sanjay; Limper, Andrew H

2016-12-01

A 19-year-old male with a history of idiopathic panuveitis, currently taking methotrexate and infliximab, presented to our institution with 6 weeks of cough, dyspnoea and fevers. He had failed outpatient antimicrobial therapy. Computerised tomography (CT) of the chest revealed the presence of a lobar pneumonia and he was treated with broad spectrum antibiotics, which did not improve his symptoms. Bronchoalveolar lavage was performed with a transbronchial lung biopsy because of the diagnostic uncertainty of the patient's presentation. Pathology revealed non-budding yeasts, consistent with Pneumocystis Serological and urine studies were positive for both Histoplasma and Blastomyces The diagnosis of Histoplasma pneumonia was made because of the presentation being inconsistent with Pneumocystis pneumonia, and serology, urine and pathology testing being more consistent with Histoplasma The patient was treated with oral itraconazole and was doing well at follow-up 12 weeks after hospitalisation. © Royal College of Physicians 2016. All rights reserved.

PET scanning in head and neck oncology: a review.

PubMed

McGuirt, W F; Greven, K; Williams, D; Keyes, J W; Watson, N; Cappellari, J O; Geisinger, K R

1998-05-01

The objective of this study was to review and describe the usage of fluorine-labeled deoxyglucose (FDG) and positron emission tomography (PET) in the diagnosis and management of head and neck cancer. Several prospective series,-including 159 newly diagnosed and previously untreated and 23 previously irradiated head and neck squamous cell carcinoma patients initially seen at the Wake Forest University Medical Center and evaluated by clinical examination, conventional computed tomography/ magnetic resonance imaging (CT/MRI) scans, PET scans, and histopathologic studies,-were reviewed and the findings summarized for comparison of the correct differentiation of primary and metastatic cancers and for postirradiation tumor clearance in a subsegment of those cases. Positron emission tomography scanning using a fluorine-labeled deoxyglucose (FDG) radiotracer proved as reliable as conventional scanning for primary and metastatic tumor identification. Compared with clinical examination, PET was better for identification of nodal metastatic tumors but poorer for small primary tumors. For previously irradiated patients treated at least 4 months before the test, PET scanning was clearly superior to clinical examination and conventional imaging in differentiating tumor recurrence from soft-tissue irradiation effects. Fluorine-labeled deoxyglucose-PET scanning is comparable to conventional imaging of head and neck cancers in detecting primary and metastatic carcinoma. Lack of anatomic detail remains its major drawback. Currently, its greatest role is in the evaluation of the postradiotherapy patient.

Use of PET/CT scanning in cancer patients: technical and practical considerations

PubMed Central

2005-01-01

This overview of the oncologic applications of positron emission tomography (PET) focuses on the technical aspects and clinical applications of a newer technique: the combination of a PET scanner and a computed tomography (CT) scanner in a single (PET/CT) device. Examples illustrate how PET/CT contributes to patient care and improves upon the previous state-of-the-art method of comparing a PET scan with a separate CT scan. Finally, the author presents some of the results from studies of PET/CT imaging that are beginning to appear in the literature. PMID:16252023

Effect of furosemide administration before F-18 fluorodeoxyglucose positron emission tomography/computed tomography on urine radioactivity and detection of uterine cervical cancer.

PubMed

d'Amico, Andrea; Gorczewska, Izabela; Gorczewski, Kamil; Turska-d'Amico, Maria; Di Pietro, Marco

2014-01-01

In evaluating uterine cervical cancer with ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), there may be overlap between the FDG activity at tumor sites and nonspecific radioactivity in the urine. We evaluated the efficacy of furosemide premedication with routine hydration to obtain better contrast and less overlap between cervical cancer and the urinary bladder. We retrospectively evaluated 166 patients who had primary or relapsed cervical cancer and underwent FDG PET/CT scanning with (133 patients) or without (33 patients) furosemide premedication (10 mg intravenous, slowly injected 30 min before the scan). We calculated bladder and tumor maximum and median standardized uptake value (SUVmax and SUVmed), and overlap between tumor and urinary activity was detected visually. Overlap between urinary and tumor radioactivity was observed in 8 of 133 scans (6%) in patients who receive furosemide and in 3 of 33 scans (9%) in patients who did not receive furosemide. The SUVmax and SUVmed for the bladder were significantly lower in patients who were pretreated with furosemide (SUVmax, 6.3; SUVmed, 4.6) than patients who were not pretreated with furosemide (SUVmax, 8.8 [P ≤ 0.008]; SUVmed, 6.5 [P ≤ 0.002]). The tumor SUVmax and SUVmed were similar between the patient groups. Furosemide premedication before FDG PET/CT scanning may enable improved evaluation of activity and extension of cervical cancer.

REPRODUCIBILITY OF VESSEL DENSITY MEASUREMENT WITH OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN EYES WITH AND WITHOUT RETINOPATHY.

PubMed

You, Qisheng; Freeman, William R; Weinreb, Robert N; Zangwill, Linda; Manalastas, Patricia I C; Saunders, Luke J; Nudleman, Eric

2017-08-01

To determine the intravisit and intervisit reproducibility of optical coherence tomography angiography measurements of macular vessel density in eyes with and without retinal diseases. Fifteen healthy volunteers and 22 patients with retinal diseases underwent repeated optical coherence tomography angiography (Angiovue Imaging System, Optovue Inc) scans after pupil dilation on 2 separate visit days. For each visit day, the eyes were scanned twice. Vessel density defined as the proportion of vessel area with flowing blood over the total measurement area was calculated using Angiovue software. Intravisit and intervisit reproducibility were summarized as coefficient of variations and intraclass correlation coefficients were calculated from variance component models. The coefficient of variations representing the intravisit reproducibility of the superficial macular vessel density measurements for different quadrants on 3 mm × 3-mm scans varied from 2.1% to 4.9% and 3.4% to 6.8% for healthy and diseased eyes, respectively, and for the intervisit it was 2.9% to 5.1% and 4.0% to 6.8%, respectively. The coefficient of variations were lower in healthy eyes than in diseased eyes, lower for intravisit than for intervisit, lower on 3 mm × 3-mm scans than on 6 mm × 6-mm scans, and lower for paracentral subfields than for central subfield. The evidence presented here demonstrates good reproducibility of optical coherence tomography angiography for measurement of superficial macula vessel density in both healthy eyes and eyes with diabetic retinopathy without diabetic macular edema.

Phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography

PubMed Central

Ludlow, John B.; Walker, Cameron

2013-01-01

Introduction Increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern with the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. Methods Effective doses resulting from various combinations of field size, and field location comparing child and adult anthropomorphic phantoms using the recently introduced i-CAT FLX cone-beam computed tomography unit were measured with Optical Stimulated Dosimetry using previously validated protocols. Scan protocols included High Resolution (360° rotation, 600 image frames, 120 kVp, 5 mA, 7.4 sec), Standard (360°, 300 frames, 120 kVp, 5 mA, 3.7 sec), QuickScan (180°, 160 frames, 120 kVp, 5 mA, 2 sec) and QuickScan+ (180°, 160 frames, 90 kVp, 3 mA, 2 sec). Contrast-to-noise ratio (CNR) was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. Results Child phantom doses were on average 36% greater than Adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than Standard protocols for child (p=0.0167) and adult (p=0.0055) phantoms. 13×16 cm cephalometric fields of view ranged from 11–85 μSv in the adult phantom and 18–120 μSv in the child for QuickScan+ and Standard protocols respectively. CNR was reduced by approximately 2/3rds comparing QuickScan+ to Standard exposure parameters. Conclusions QuickScan+ effective doses are comparable to conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off may be acceptable for certain diagnostic tasks such as interim assessment of treatment results. PMID:24286904

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.

Comparison of Radiation Dose and Image Quality of Triple-Rule-Out Computed Tomography Angiography Between Conventional Helical Scanning and a Strategy Incorporating Sequential Scanning

PubMed Central

Manheimer, Eric D.; Peters, M. Robert; Wolff, Steven D.; Qureshi, Mehreen A.; Atluri, Prashanth; Pearson, Gregory D.N.; Einstein, Andrew J.

2011-01-01

Triple-rule-out computed tomography angiography (TRO CTA), performed to evaluate the coronary arteries, pulmonary arteries, and thoracic aorta, has been associated with high radiation exposure. Utilization of sequential scanning for coronary computed tomography angiography (CCTA) reduces radiation dose. The application of sequential scanning to TRO CTA is much less well defined. We analyzed radiation dose and image quality from TRO CTA performed in a single outpatient center, comparing scans from a period during which helical scanning with electrocardiographically controlled tube current modulation was used for all patients (n=35) and after adoption of a strategy incorporating sequential scanning whenever appropriate (n=35). Sequential scanning was able to be employed in 86% of cases. The sequential-if-appropriate strategy, compared to the helical-only strategy, was associated with a 61.6% dose decrease (mean dose-length product [DLP] of 439 mGy×cm vs 1144 mGy×cm and mean effective dose of 7.5 mSv vs 19.4 mSv, respectively, p<0.0001). Similarly, there was a 71.5% dose reduction among 30 patients scanned with the sequential protocol compared to 40 patients scanned with the helical protocol under either strategy (326 mGy×cm vs 1141 mGy×cm and 5.5 mSv vs 19.4 mSv, respectively, p<0.0001). Although image quality did not differ between strategies, there was a non-statistically significant trend towards better quality in the sequential protocol compared to the helical protocol. In conclusion, approaching TRO CTA with a diagnostic strategy of sequential scanning as appropriate offers a marked reduction in radiation dose while maintaining image quality. PMID:21306693

Lymphadenopathy resulting from acute toxoplasmosis mimicking relapse of non-Hodgkin's lymphoma on fluorodeoxyglucose positron emission tomography/computed tomography.

PubMed

Joshi, Prathamesh; Lele, Vikram; Mahajan, Pravin

2012-01-01

We report a case documenting fluorodeoxyglucose (FDG) accumulation in cervical, supraclavicular and axillary lymph nodes resulting from acute toxoplasmosis. A 50-year-old Indian female with history of non-Hodgkin's lymphoma (NHL) of left breast, postchemotherapy status, was found to have hypermetabolic right cervical, supraclavicular and axillary lymph nodes on a surveillance FDG positron emission tomography/computed tomography (PET/CT) scan. Her previous two PET/CT scans were unremarkable with no evidence of metabolically active disease. Therefore, a differential diagnosis of relapse of NHL versus infectious/inflammatory pathology was raised in the report. Biopsy of axillary lymph node demonstrated features characteristic of toxoplasmosis. The serological test results were also compatible with acute toxoplasmosis infection. Infective and inflammatory diseases are known to accumulate FDG, resulting in false positives for malignancy. This case demonstrates lymph nodal toxoplasmosis as a potential cause of false positive FDG PET/CT findings in patients with known malignancy and highlights the importance of histopathological and laboratory correlation for the accurate interpretation of FDG PET/CT scans.

Mcps-range photon-counting x-ray computed tomography system

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Enomoto, Toshiyuki; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-10-01

10 Mcps photon counting was carried out using a detector consisting of a 2.0 mm-thick ZnO (zinc oxide) single-crystal scintillator and an MPPC (multipixel photon counter) module in an X-ray computed tomography (CT) system. The maximum count rate was 10 Mcps (mega counts per second) at a tube voltage of 70 kV and a tube current of 2.0 mA. Next, a photon-counting X-ray CT system consists of an X-ray generator, a turntable, a scan stage, a two-stage controller, the ZnO-MPPC detector, a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan with a scan velocity of 25 mm/s. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The exposure time for obtaining a tomogram was 600 s at a scan step of 0.5 mm and a rotation step of 1.0°, and photon-counting CT was accomplished using iodine-based contrast media.

Utility of screening computed tomography of chest, abdomen and pelvis in patients after heart transplantation.

PubMed

Dasari, Tarun W; Pavlovic-Surjancev, Biljana; Dusek, Linda; Patel, Nilamkumar; Heroux, Alain L

2011-12-01

Malignancy is a late cause of mortality in heart transplant recipients. It is unknown if screening computed tomography scan would lead to early detection of such malignancies or serious vascular anomalies post heart transplantation. This is a single center observational study of patients undergoing surveillance computed tomography of chest, abdomen and pelvis at least 5 years after transplantation. Abnormal findings, included pulmonary nodules, lymphadenopathy and intra-thoracic and intra-abdominal masses and vascular anomalies such as abdominal aortic aneurysm. The clinical follow up of each of these major abnormal findings is summarized. A total of 63 patients underwent computed tomography scan of chest, abdomen and pelvis at least 5 years after transplantation. Of these, 54 (86%) were male and 9 (14%) were female. Mean age was 52±9.2 years. Computed tomography revealed 1 lung cancer (squamous cell) only. Non specific pulmonary nodules were seen in 6 patients (9.5%). The most common incidental finding was abdominal aortic aneurysms (N=6 (9.5%)), which necessitated follow up computed tomography (N=5) or surgery (N=1). Mean time to detection of abdominal aortic aneurysms from transplantation was 14.6±4.2 years. Mean age at the time of detection of abdominal aortic aneurysms was 74.5±3.2 years. Screening computed tomography scan in patients 5 years from transplantation revealed only one malignancy but lead to increased detection of abdominal aortic aneurysms. Thus the utility is low in terms of detection of malignancy. Based on this study we do not recommend routine computed tomography post heart transplantation. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Do Computerised Training Programmes Designed to Improve Working Memory Work?

ERIC Educational Resources Information Center

Apter, Brian J. B.

2012-01-01

A critical review of working memory training research during the last 10 years is provided. Particular attention is given to research that has attempted to investigate the efficacy of commercially marketed computerised training programmes such as "Cogmed" and "Jungle Memory". Claimed benefits are questioned on the basis that research methodologies…

Demography, Social Structure and Learning through Life

ERIC Educational Resources Information Center

van der Veen, Ruud

2010-01-01

The modernisation of the Western world during the last two centuries has been a mix of industrialisation/computerisation and urbanisation. Consequently, reports on the future of adult learning and adult education have been a mix on the one hand of the learning requirements that follow from industrialisation/computerisation and on the other hand,…

Computerised Accounting Software; A Curriculum That Enhances an Accounting Programme

ERIC Educational Resources Information Center

Machera, Robert P.; Machera, Precious C.

2017-01-01

There has been an outcry in commerce and industry about students who fail to perform in the accounting department due to lack of "practical accounting skills". It is from this background that the researchers were motivated to investigate the impact of a Computerised Accounting Software Curriculum that enhances an Accounting Programme. At…

Differential phase microscope and micro-tomography with a Foucault knife-edge scanning filter

NASA Astrophysics Data System (ADS)

Watanabe, N.; Hashizume, J.; Goto, M.; Yamaguchi, M.; Tsujimura, T.; Aoki, S.

2013-10-01

An x-ray differential phase microscope with a Foucault knife-edge scanning filter was set up at the bending magnet source BL3C, Photon Factory. A reconstructed phase profile from the differential phase image of an aluminium wire at 5.36 keV was fairly good agreement with the numerical simulation. Phase tomography of a biological specimen, such as an Artemia cyst, could be successfully demonstrated.

Computerised therapies for anxiety and depression in children and young people: a systematic review and meta-analysis.

PubMed

Pennant, Mary E; Loucas, Christina E; Whittington, Craig; Creswell, Cathy; Fonagy, Peter; Fuggle, Peter; Kelvin, Raphael; Naqvi, Sabrina; Stockton, Sarah; Kendall, Tim

2015-04-01

One quarter of children and young people (CYP) experience anxiety and/or depression before adulthood, but treatment is sometimes unavailable or inadequate. Self-help interventions may have a role in augmenting treatment and this work aimed to systematically review the evidence for computerised anxiety and depression interventions in CYP aged 5-25 years old. Databases were searched for randomised controlled trials and 27 studies were identified. For young people (12-25 years) with risk of diagnosed anxiety disorders or depression, computerised CBT (cCBT) had positive effects for symptoms of anxiety (SMD -0.77, 95% CI -1.45 to -0.09, k = 6, N = 220) and depression (SMD -0.62, 95% CI -1.13 to -0.11, k = 7, N = 279). In a general population study of young people, there were small positive effects for anxiety (SMD -0.15, 95% CI -0.26 to -0.03; N = 1273) and depression (SMD -0.15, 95% CI -0.26 to -0.03; N = 1280). There was uncertainty around the effectiveness of cCBT in children (5-11 years). Evidence for other computerised interventions was sparse and inconclusive. Computerised CBT has potential for treating and preventing anxiety and depression in clinical and general populations of young people. Further program development and research is required to extend its use and establish its benefit in children. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development and evaluation of a centralised computerised registry for ureteric stents: completing the audit cycle.

PubMed

Davis, N F; Murray, G; O'Connor, T; Browne, C; MacCraith, E; Galvin, D; Mulvin, D; Quinlan, D; Lennon, G

2017-11-01

A forgotten ureteric stent may result in severe renal impairment leading to nephrectomy. To compare the effectiveness of a centralised computerised registry for monitoring ureteric stent activity with a previously established theatre stent logbook system. This prospective audit was performed in two 9-monthly intervals. During the first interval, insertion/removal of a ureteric stent was documented in a specific theatre stent logbook. In the second interval, an electronic centralised computerised registry was developed to document insertion/removal of a ureteric stent onto an accessible hospital server. A computerised traffic-light system was also developed to identify patients with an indwelling stent for >3 months. The primary outcome variable was the number of prolonged indwelling ureteric stents in both groups. During the first time interval, 188 ureteric stents were inserted and 182 (96%) were removed or changed. Six (4%) patients underwent insertion of a ureteric stent for a prolonged period of time (>6 months). This subgroup required complex endourological intervention for stent removal due to encrustation. During the second time interval, 157 ureteric stents were inserted and all patients had their stent removed or changed within 6 months. No patients in this group were lost to follow-up. This study demonstrates that a centralised computerised ureteric stent registry is superior to a conventional logbook for monitoring ureteric stent activity. We propose the introduction a centralised nationalised ureteric stent registry for eliminating the potential for prolonged or forgotten ureteric stents.

An electron beam linear scanning mode for industrial limited-angle nano-computed tomography.

PubMed

Wang, Chengxiang; Zeng, Li; Yu, Wei; Zhang, Lingli; Guo, Yumeng; Gong, Changcheng

2018-01-01

Nano-computed tomography (nano-CT), which utilizes X-rays to research the inner structure of some small objects and has been widely utilized in biomedical research, electronic technology, geology, material sciences, etc., is a high spatial resolution and non-destructive research technique. A traditional nano-CT scanning model with a very high mechanical precision and stability of object manipulator, which is difficult to reach when the scanned object is continuously rotated, is required for high resolution imaging. To reduce the scanning time and attain a stable and high resolution imaging in industrial non-destructive testing, we study an electron beam linear scanning mode of nano-CT system that can avoid mechanical vibration and object movement caused by the continuously rotated object. Furthermore, to further save the scanning time and study how small the scanning range could be considered with acceptable spatial resolution, an alternating iterative algorithm based on ℓ 0 minimization is utilized to limited-angle nano-CT reconstruction problem with the electron beam linear scanning mode. The experimental results confirm the feasibility of the electron beam linear scanning mode of nano-CT system.

An electron beam linear scanning mode for industrial limited-angle nano-computed tomography

NASA Astrophysics Data System (ADS)

Wang, Chengxiang; Zeng, Li; Yu, Wei; Zhang, Lingli; Guo, Yumeng; Gong, Changcheng

2018-01-01

Nano-computed tomography (nano-CT), which utilizes X-rays to research the inner structure of some small objects and has been widely utilized in biomedical research, electronic technology, geology, material sciences, etc., is a high spatial resolution and non-destructive research technique. A traditional nano-CT scanning model with a very high mechanical precision and stability of object manipulator, which is difficult to reach when the scanned object is continuously rotated, is required for high resolution imaging. To reduce the scanning time and attain a stable and high resolution imaging in industrial non-destructive testing, we study an electron beam linear scanning mode of nano-CT system that can avoid mechanical vibration and object movement caused by the continuously rotated object. Furthermore, to further save the scanning time and study how small the scanning range could be considered with acceptable spatial resolution, an alternating iterative algorithm based on ℓ0 minimization is utilized to limited-angle nano-CT reconstruction problem with the electron beam linear scanning mode. The experimental results confirm the feasibility of the electron beam linear scanning mode of nano-CT system.

Magnetic resonance imaging and computerized tomography in malignant external otitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gherini, S.G.; Brackmann, D.E.; Bradley, W.G.

1986-05-01

In malignant external otitis (MEO), determining the anatomic extent of disease and evaluating the physiologic response to therapy remain a problem. Magnetic resonance imaging (MRI) has recently become available in limited clinical settings. Four patients with MEO were evaluated using MRI, computerized tomography (CT), technetium-99 (Tc-99) bone scanning, and gallium-67 citrate (Ga-67 citrate) scanning. MRI is superior to CT, Tc-99 bone scanning, and Ga-67 citrate scanning in evaluating the anatomic extent of soft tissue changes in MEO. MRI alone cannot be relied upon to determine the physiologic response to therapy. MRI can, however, serve as a valuable guide to themore » interpretation of Tc-99 bone and Ga-67 citrate scans, and in this respect, MRI is extremely useful in the treatment of MEO.« less

Evaluation of three indices for biofilm accumulation on complete dentures.

PubMed

Paranhos, Helena de Freitas Oliveira; Lovato da Silva, Claudia Helena; de Souza, Raphael Freitas; Pontes, Karina Matthes de Freitas

2010-03-01

The objective of this study was to evaluate the accuracy and reproducibility of three complete denture biofilm indices (Prosthesis Hygiene Index; Jeganathan et al. Index; Budtz-Jørgensen Index) by means of a computerised comparison method. Clinical studies into denture hygiene have employed a large number of biofilm indices among their outcome variables. However, the knowledge about the validity of these indices is still scarce. Sixty-two complete denture wearers were selected. The internal surfaces of the upper complete dentures were stained (5% erythrosine) and photographed. The slides were projected on paper, and the biofilm indices were applied over the photos by means of a scoring method. For the computerised method, the areas (total and biofilm-covered) were measured by dedicated software (Image Tool). In addition, to compare the results of the computerised method and Prosthetic Hygiene Index, a new scoring scale (including four and five graded) was introduced. For the Jeganathan et al. and Budtz-Jørgensen indices, the original scales were used. Values for each index were compared with the computerised method by the Friedman test. Their reproducibility was measured by means of weighed kappa. Significance for both tests was set at 0.05. The indices tested provided similar mean measures but they tended to overestimate biofilm coverage when compared with the computerised method (p < 0.001). Agreement between the Prosthesis Hygiene Index and the computerised method was not significant, regardless of the scale used. Jeghanathan et al. Index showed weak agreement, and consistent results were found for Budtz-Jorgensen Index (kappa = 0.19 and 0.39 respectively). Assessment of accuracy for the biofilm indices showed instrument bias that was similar among the tested methods. Weak inter-instrument reproducibility was found for the indices, except for the Budtz-Jørgensen Index. This should be the method of choice for clinical studies when more sophisticated approaches are not possible.

Chorioretinal dysplasia, hydranencephaly, and intracranial calcifications: pseudo-TORCH or a new syndrome?

PubMed

Watts, P; Kumar, N; Ganesh, A; Sastry, P; Pilz, D; Levin, A V; Chitayat, D

2008-05-01

To report the association of severe chorioretinal dysplasia, hydranencephaly, microcephaly, and intracranial calcification in children with no evidence of intrauterine infections. Two unrelated female infants with visually inattentive behaviour, hydranencephaly, and intracranial calcification were referred for an ophthalmological opinion. The fundus examination and computerised tomograms (CT scans) of head were similar in both children. There was bilateral extensive chorioretinal dysplasia, intracranial calcifications, and hydranencephaly. Serology was negative for acquired intrauterine congenital infections. We report two cases that may represent a new syndrome or the more severe end of the spectrum of the pseudo-TORCH (toxoplasma, rubella, cytomegalovirus, and herpes simplex) syndrome. The association of chorioretinal dysplasia with the pseudo-TORCH syndrome has not been reported previously.

Comparison of Image Quality and Radiation Dose of Coronary Computed Tomography Angiography Between Conventional Helical Scanning and a Strategy Incorporating Sequential Scanning

PubMed Central

Einstein, Andrew J.; Wolff, Steven D.; Manheimer, Eric D.; Thompson, James; Terry, Sylvia; Uretsky, Seth; Pilip, Adalbert; Peters, M. Robert

2009-01-01

Radiation dose from coronary computed tomography angiography may be reduced using a sequential scanning protocol rather than a conventional helical scanning protocol. Here we compare radiation dose and image quality from coronary computed tomography angiography in a single center between an initial period during which helical scanning with electrocardiographically-controlled tube current modulation was used for all patients (n=138) and after adoption of a strategy incorporating sequential scanning whenever appropriate (n=261). Using the sequential-if-appropriate strategy, sequential scanning was employed in 86.2% of patients. Compared to the helical-only strategy, this strategy was associated with a 65.1% dose reduction (mean dose-length product of 305.2 vs. 875.1 and mean effective dose of 14.9 mSv vs. 5.2 mSv, respectively), with no significant change in overall image quality, step artifacts, motion artifacts, or perceived image noise. For the 225 patients undergoing sequential scanning, the dose-length product was 201.9 ± 90.0 mGy·cm, while for patients undergoing helical scanning under either strategy, the dose-length product was 890.9 ± 293.3 mGy·cm (p<0.0001), corresponding to mean effective doses of 3.4 mSv and 15.1 mSv, respectively, a 77.5% reduction. Image quality was significantly greater for the sequential studies, reflecting the poorer image quality in patients undergoing helical scanning in the sequential-if-appropriate strategy. In conclusion, a sequential-if-appropriate diagnostic strategy reduces dose markedly compared to a helical-only strategy, with no significant difference in image quality. PMID:19892048

A comparison of sequential and spiral scanning techniques in brain CT.

PubMed

Pace, Ivana; Zarb, Francis

2015-01-01

To evaluate and compare image quality and radiation dose of sequential computed tomography (CT) examinations of the brain and spiral CT examinations of the brain imaged on a GE HiSpeed NX/I Dual Slice 2CT scanner. A random sample of 40 patients referred for CT examination of the brain was selected and divided into 2 groups. Half of the patients were scanned using the sequential technique; the other half were scanned using the spiral technique. Radiation dose data—both the computed tomography dose index (CTDI) and the dose length product (DLP)—were recorded on a checklist at the end of each examination. Using the European Guidelines on Quality Criteria for Computed Tomography, 4 radiologists conducted a visual grading analysis and rated the level of visibility of 6 anatomical structures considered necessary to produce images of high quality. The mean CTDI(vol) and DLP values were statistically significantly higher (P <.05) with the sequential scans (CTDI(vol): 22.06 mGy; DLP: 304.60 mGy • cm) than with the spiral scans (CTDI(vol): 14.94 mGy; DLP: 229.10 mGy • cm). The mean image quality rating scores for all criteria of the sequential scanning technique were statistically significantly higher (P <.05) in the visual grading analysis than those of the spiral scanning technique. In this local study, the sequential technique was preferred over the spiral technique for both overall image quality and differentiation between gray and white matter in brain CT scans. Other similar studies counter this finding. The radiation dose seen with the sequential CT scanning technique was significantly higher than that seen with the spiral CT scanning technique. However, image quality with the sequential technique was statistically significantly superior (P <.05).

A Simple Inexpensive Procedure for Illustrating Some Principles of Tomography

ERIC Educational Resources Information Center

Darvey, Ivan G.

2013-01-01

The experiment proposed here illustrates some concepts of tomography via a qualitative determination of the relative concentration of various dilutions of food dye without "a priori" knowledge of the concentration of each dye mixture. This is performed in a manner analogous to computed tomography (CT) scans. In order to determine the…

Radionuclide Ventriculography or Radionuclide Angiography (MUGA Scan)

MedlinePlus

... Attack Heart Failure Myocardial Perfusion Imaging (MPI) Single Photon Emission Computed Tomography (SPECT) Positron Emission Tomography (PET) ... stroke. Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms in ...

Breast ultrasound tomography with two parallel transducer arrays: preliminary clinical results

NASA Astrophysics Data System (ADS)

Huang, Lianjie; Shin, Junseob; Chen, Ting; Lin, Youzuo; Intrator, Miranda; Hanson, Kenneth; Epstein, Katherine; Sandoval, Daniel; Williamson, Michael

2015-03-01

Ultrasound tomography has great potential to provide quantitative estimations of physical properties of breast tumors for accurate characterization of breast cancer. We design and manufacture a new synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays. The distance of these two transducer arrays is adjustable for scanning breasts with different sizes. The ultrasound transducer arrays are translated vertically to scan the entire breast slice by slice and acquires ultrasound transmission and reflection data for whole-breast ultrasound imaging and tomographic reconstructions. We use the system to acquire patient data at the University of New Mexico Hospital for clinical studies. We present some preliminary imaging results of in vivo patient ultrasound data. Our preliminary clinical imaging results show promising of our breast ultrasound tomography system with two parallel transducer arrays for breast cancer imaging and characterization.

Applying LED in full-field optical coherence tomography for gastrointestinal endoscopy

NASA Astrophysics Data System (ADS)

Yang, Bor-Wen; Wang, Yu-Yen; Juan, Yu-Shan; Hsu, Sheng-Jie

2015-08-01

Optical coherence tomography (OCT) has become an important medical imaging technology due to its non-invasiveness and high resolution. Full-field optical coherence tomography (FF-OCT) is a scanning scheme especially suitable for en face imaging as it employs a CMOS/CCD device for parallel pixels processing. FF-OCT can also be applied to high-speed endoscopic imaging. Applying cylindrical scanning and a right-angle prism, we successfully obtained a 360° tomography of the inner wall of an intestinal cavity through an FF-OCT system with an LED source. The 10-μm scale resolution enables the early detection of gastrointestinal lesions, which can increase detection rates for esophageal, stomach, or vaginal cancer. All devices used in this system can be integrated by MOEMS technology to contribute to the studies of gastrointestinal medicine and advanced endoscopy technology.

Effectiveness of a Computerised Working Memory Training in Adolescents with Mild to Borderline Intellectual Disabilities

ERIC Educational Resources Information Center

Van der Molen, M. J.; Van Luit, J. E. H.; Van der Molen, M. W.; Klugkist, I.; Jongmans, M. J.

2010-01-01

Background: The goal of this study is to evaluate the effectiveness of a computerised working memory (WM) training on memory, response inhibition, fluid intelligence, scholastic abilities and the recall of stories in adolescents with mild to borderline intellectual disabilities attending special education. Method: A total of 95 adolescents with…

Evaluation of Computerised Reading-Assistance Systems for Reading Japanese Texts--From a Linguistic Point of View

ERIC Educational Resources Information Center

Toyoda, Etsuko

2016-01-01

For second-language learners to effectively and efficiently gather information from online texts in their target language, a well-designed computerised system to assist their reading is essential. While many articles and websites which introduce electronic second-language learning tools exist, evaluation of their functions in relation to the…

An Investigation of Integrative and Independent Listening Test Tasks in a Computerised Academic English Test

ERIC Educational Resources Information Center

Wei, Wei; Zheng, Ying

2017-01-01

This research provided a comprehensive evaluation and validation of the listening section of a newly introduced computerised test, Pearson Test of English Academic (PTE Academic). PTE Academic contains 11 item types assessing academic listening skills either alone or in combination with other skills. First, task analysis helped identify skills…

Using a Computerised Graphics Package to Achieve a Technology-Oriented Classroom

ERIC Educational Resources Information Center

Aladejana, Francisca; Idowu, Lanre

2009-01-01

The present situation in Nigeria involves students of fine arts, a practical-oriented subject, being exposed to poor methods of teaching with consequent poor performances. This study examined the extent to which the use of a computerised graphics package could make the classroom technology-oriented and affect the performance of learners. This is…

A New Computerised Advanced Theory of Mind Measure for Children with Asperger Syndrome: The ATOMIC

ERIC Educational Resources Information Center

Beaumont, Renae B.; Sofronoff, Kate

2008-01-01

This study examined the ability of children with Asperger Syndrome (AS) to attribute mental states to characters in a new computerised, advanced theory of mind measure: The Animated Theory of Mind Inventory for Children (ATOMIC). Results showed that children with AS matched on IQ, verbal comprehension, age and gender performed equivalently on…

Student Evaluation in Higher Education: A Comparison between Computer Assisted Assessment and Traditional Evaluation

ERIC Educational Resources Information Center

Ghilay, Yaron; Ghilay, Ruth

2012-01-01

The study examined advantages and disadvantages of computerised assessment compared to traditional evaluation. It was based on two samples of college students (n=54) being examined in computerised tests instead of paper-based exams. Students were asked to answer a questionnaire focused on test effectiveness, experience, flexibility and integrity.…

Is there a simple, definitive, and cost-effective way to diagnose osteomyelitis in the pressure ulcer patient?

PubMed

Larson, David L; Gilstrap, Jarom; Simonelic, Kevin; Carrera, Guillermo F

2011-02-01

Despite advances in managing pressure ulcers, there is still no definitive way to diagnose bone infection (osteomyelitis) short of open biopsy. An effective, less invasive diagnostic method might result in cost savings and improved care; however, needle aspiration, computed tomography scan, magnetic resonance imaging, ultrasound, and bone scans have proven unsatisfactory in predicting osteomyelitis. The authors reviewed preoperative radiologic studies of stage IV pressure ulcer patients and their bone biopsy results to determine which radiologic studies are most diagnostic for osteomyelitis. Patients (n = 44) having surgical débridement of stage IV ulcers with open bone biopsy after prior radiographic imaging (plain films, ultrasound, computed tomography, magnetic resonance imaging, and/or nuclear bone scans) were included. Studies were interpreted by a single musculoskeletal radiologist blinded to information from the medical record and following standard radiologic criteria for the diagnosis of osteomyelitis. The percentage of patients with biopsy-proven osteomyelitis identified with imaging was 50 percent using a computed tomography scan and 88 percent using a plain film of the bony area of involvement. The overall sensitivity of either radiologic study was 61 percent. The percentage of patients without osteomyelitis identified as not having the condition by imaging was 85 percent for the computed tomography scan and 32 percent for the plain film. Overall specificity of both studies was 69 percent. Preoperative radiologic studies for osteomyelitis in a pressure ulcer are far from definitive; however, if a radiologic study is used to make that diagnosis in a stage IV pressure ulcer, it would appear that a plain film would suffice.

Slit scan radiographic system for intermediate size rocket motors

NASA Astrophysics Data System (ADS)

Bernardi, Richard T.; Waters, David D.

1992-12-01

The development of slit-scan radiography capability for the NASA Advanced Computed Tomography Inspection System (ACTIS) computed tomography (CT) scanner at MSFC is discussed. This allows for tangential case interface (bondline) inspection at 2 MeV of intermediate-size rocket motors like the Hawk. Motorized mounting fixture hardware was designed, fabricated, installed, and tested on ACTIS. The ACTIS linear array of x-ray detectors was aligned parallel to the tangent line of a horizontal Hawk motor case. A 5 mm thick x-ray fan beam was used. Slit-scan images were produced with continuous rotation of a horizontal Hawk motor. Image features along Hawk motor case interfaces were indicated. A motorized exit cone fixture for ACTIS slit-scan inspection was also provided. The results of this SBIR have shown that slit scanning is an alternative imaging technique for case interface inspection. More data is required to qualify the technique for bondline inspection.

Bone Scan

MedlinePlus

... your doctor might order additional imaging called single-photon emission computerized tomography (SPECT). This imaging can help ... radioactivity from the tracers is usually completely eliminated two days after the scan. Results A doctor who ...

Automated volumetric segmentation of retinal fluid on optical coherence tomography

PubMed Central

Wang, Jie; Zhang, Miao; Pechauer, Alex D.; Liu, Liang; Hwang, Thomas S.; Wilson, David J.; Li, Dengwang; Jia, Yali

2016-01-01

We propose a novel automated volumetric segmentation method to detect and quantify retinal fluid on optical coherence tomography (OCT). The fuzzy level set method was introduced for identifying the boundaries of fluid filled regions on B-scans (x and y-axes) and C-scans (z-axis). The boundaries identified from three types of scans were combined to generate a comprehensive volumetric segmentation of retinal fluid. Then, artefactual fluid regions were removed using morphological characteristics and by identifying vascular shadowing with OCT angiography obtained from the same scan. The accuracy of retinal fluid detection and quantification was evaluated on 10 eyes with diabetic macular edema. Automated segmentation had good agreement with manual segmentation qualitatively and quantitatively. The fluid map can be integrated with OCT angiogram for intuitive clinical evaluation. PMID:27446676

A review of setup error in supine breast radiotherapy using cone-beam computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batumalai, Vikneswary, E-mail: Vikneswary.batumalai@sswahs.nsw.gov.au; Liverpool and Macarthur Cancer Therapy Centres, New South Wales; Ingham Institute of Applied Medical Research, Sydney, New South Wales

2016-10-01

Setup error in breast radiotherapy (RT) measured with 3-dimensional cone-beam computed tomography (CBCT) is becoming more common. The purpose of this study is to review the literature relating to the magnitude of setup error in breast RT measured with CBCT. The different methods of image registration between CBCT and planning computed tomography (CT) scan were also explored. A literature search, not limited by date, was conducted using Medline and Google Scholar with the following key words: breast cancer, RT, setup error, and CBCT. This review includes studies that reported on systematic and random errors, and the methods used when registeringmore » CBCT scans with planning CT scan. A total of 11 relevant studies were identified for inclusion in this review. The average magnitude of error is generally less than 5 mm across a number of studies reviewed. The common registration methods used when registering CBCT scans with planning CT scan are based on bony anatomy, soft tissue, and surgical clips. No clear relationships between the setup errors detected and methods of registration were observed from this review. Further studies are needed to assess the benefit of CBCT over electronic portal image, as CBCT remains unproven to be of wide benefit in breast RT.« less

Future of computerised electrocardiography.

PubMed Central

Meijler, F L; Robles de Medina, E O; Helder, J C

1980-01-01

The advent of computerised electrocardiography has been of prime importance for the storage and retrieval of data, but none of the available systems is of universal application for analysis of patterns. Future needs require hierarchical systems of increasing degrees of complexity, depending on the source of requests, and there should be appropriate provision for review by cardiologists before the final report is issued. PMID:7000098

Review and Reward within the Computerised Peer-Assessment of Essays

ERIC Educational Resources Information Center

Davies, Phil

2009-01-01

This article details the implementation and use of a "Review Stage" within the CAP (computerised assessment by peers) tool as part of the assessment process for a post-graduate module in e-learning. It reports upon the effect of providing the students with a "second chance" in marking and commenting their peers' essays having been able to view the…

CT scan (image)

MedlinePlus

CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

Parathyroid Cancer Treatment

MedlinePlus

... of the head and neck. SPECT scan (single photon emission computed tomography scan) : A procedure that uses ... a recurrence. The parathyroid cancer usually recurs between 2 and 5 years after the first surgery , but ...

Cryo-scanning transmission electron tomography of vitrified cells.

PubMed

Wolf, Sharon Grayer; Houben, Lothar; Elbaum, Michael

2014-04-01

Cryo-electron tomography (CET) of fully hydrated, vitrified biological specimens has emerged as a vital tool for biological research. For cellular studies, the conventional imaging modality of transmission electron microscopy places stringent constraints on sample thickness because of its dependence on phase coherence for contrast generation. Here we demonstrate the feasibility of using scanning transmission electron microscopy for cryo-tomography of unstained vitrified specimens (CSTET). We compare CSTET and CET for the imaging of whole bacteria and human tissue culture cells, finding favorable contrast and detail in the CSTET reconstructions. Particularly at high sample tilts, the CSTET signals contain more informative data than energy-filtered CET phase contrast images, resulting in improved depth resolution. Careful control over dose delivery permits relatively high cumulative exposures before the onset of observable beam damage. The increase in acceptable specimen thickness broadens the applicability of electron cryo-tomography.

False-positive 18F-fluorodeoxyglucose positron emission tomography/computed tomography in a patient with metallic implants following chondrosarcoma resection

PubMed Central

ZHOU, PU; TANG, JINLIANG; ZHANG, DONG; LI, GUANGHUI

2016-01-01

Positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose (18F-FDG) has been used for the staging and evaluation of recurrence in cancer patients. We herein report a false-positive result of 18F-FDG PET/computed tomography (CT) scan in a patient following chondrosarcoma resection and metallic implanting. A 35-year-old male patient with chondrosarcoma of the left iliac bone underwent radical resection, metal brace implanting and radiotherapy. A high uptake of 18F-FDG was observed in the metallic implants and adjacent tissue during PET/CT scanning in the 5th year of follow-up. Tissue biopsy and follow-up examination identified no tumor recurrence or infection at these sites, suggesting that the results of 18F-FDG PET/CT must be interpreted with caution in cancer patients with metallic implants. PMID:27123290

False-positive 18F-fluorodeoxyglucose positron emission tomography/computed tomography in a patient with metallic implants following chondrosarcoma resection.

PubMed

Zhou, P U; Tang, Jinliang; Zhang, Dong; Li, Guanghui

2016-05-01

Positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose ( 18 F-FDG) has been used for the staging and evaluation of recurrence in cancer patients. We herein report a false-positive result of 18 F-FDG PET/computed tomography (CT) scan in a patient following chondrosarcoma resection and metallic implanting. A 35-year-old male patient with chondrosarcoma of the left iliac bone underwent radical resection, metal brace implanting and radiotherapy. A high uptake of 18 F-FDG was observed in the metallic implants and adjacent tissue during PET/CT scanning in the 5th year of follow-up. Tissue biopsy and follow-up examination identified no tumor recurrence or infection at these sites, suggesting that the results of 18 F-FDG PET/CT must be interpreted with caution in cancer patients with metallic implants.

Improving limited-projection-angle fluorescence molecular tomography using a co-registered x-ray computed tomography scan.

PubMed

Radrich, Karin; Ale, Angelique; Ermolayev, Vladimir; Ntziachristos, Vasilis

2012-12-01

We examine the improvement in imaging performance, such as axial resolution and signal localization, when employing limited-projection-angle fluorescence molecular tomography (FMT) together with x-ray computed tomography (XCT) measurements versus stand-alone FMT. For this purpose, we employed living mice, bearing a spontaneous lung tumor model, and imaged them with FMT and XCT under identical geometrical conditions using fluorescent probes for cancer targeting. The XCT data was employed, herein, as structural prior information to guide the FMT reconstruction. Gold standard images were provided by fluorescence images of mouse cryoslices, providing the ground truth in fluorescence bio-distribution. Upon comparison of FMT images versus images reconstructed using hybrid FMT and XCT data, we demonstrate marked improvements in image accuracy. This work relates to currently disseminated FMT systems, using limited projection scans, and can be employed to enhance their performance.

Hyper-spectrum scanning laser optical tomography

NASA Astrophysics Data System (ADS)

Chen, Lingling; Li, Guiye; Li, Yingchao; Liu, Lina; Liu, Ang; Hu, Xuejuan; Ruan, Shuangchen

2018-02-01

We describe a quantitative fluorescence projection tomography technique which measures the three-dimensional fluorescence spectrum in biomedical samples with size up to several millimeters. This is achieved by acquiring a series of hyperspectral images, by using laser scanning scheme, at different projection angles. We demonstrate that this technique provide a quantitative measure of the fluorescence signal by comparing the spectrum and intensity profile of a fluorescent bead phantom and also demonstrate its application to differentiating the extrinsic label and the autofluorescence in a mouse embryo.

Bochdalek hernia presenting with initial local fat infiltration of the thoracic cavity in a leukemic child.

PubMed

Kang, Zhen; Min, Xiangde; Wang, Liang

2017-03-01

Local fat infiltration of the thoracic cavity is a rare initial presentation of Bochdalek hernia. We report a case of Bochdalek hernia in a child with leukemia that demonstrated initial local fat infiltration of the thoracic cavity on computed tomography scan and progressed to an obvious diaphragmatic hernia on subsequent follow-up. We suggest that initial local fat infiltration of the thoracic cavity on computed tomography scan may indicate a potential diaphragmatic hernia.

Overview of Imaging Tests

MedlinePlus

... Overview of Imaging Tests Angiography Computed Tomography (CT) Magnetic Resonance Imaging (MRI) Plain X-Rays Radionuclide Scanning ... and radionuclide scanning Sound waves, as in ultrasonography Magnetic fields, as in magnetic resonance imaging (MRI) Substances ...

Stages of Parathyroid Cancer

MedlinePlus

... of the head and neck. SPECT scan (single photon emission computed tomography scan) : A procedure that uses ... a recurrence. The parathyroid cancer usually recurs between 2 and 5 years after the first surgery , but ...

Assessment of phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography.

PubMed

Ludlow, John B; Walker, Cameron

2013-12-01

The increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern about the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. Effective doses resulting from various combinations of field of view size and field location comparing child and adult anthropomorphic phantoms with the recently introduced i-CAT FLX cone-beam computed tomography unit (Imaging Sciences, Hatfield, Pa) were measured with optical stimulated dosimetry using previously validated protocols. Scan protocols included high resolution (360° rotation, 600 image frames, 120 kV[p], 5 mA, 7.4 seconds), standard (360°, 300 frames, 120 kV[p], 5 mA, 3.7 seconds), QuickScan (180°, 160 frames, 120 kV[p], 5 mA, 2 seconds), and QuickScan+ (180°, 160 frames, 90 kV[p], 3 mA, 2 seconds). Contrast-to-noise ratio was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. Child phantom doses were on average 36% greater than adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than standard protocols for the child (P = 0.0167) and adult (P = 0.0055) phantoms. The 13 × 16-cm cephalometric fields of view ranged from 11 to 85 μSv in the adult phantom and 18 to 120 μSv in the child phantom for the QuickScan+ and standard protocols, respectively. The contrast-to-noise ratio was reduced by approximately two thirds when comparing QuickScan+ with standard exposure parameters. QuickScan+ effective doses are comparable with conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off might be acceptable for certain diagnostic tasks such as interim assessment of treatment results. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Clinical importance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography in the management of patients with bronchoalveolar carcinoma: Role in the detection of recurrence.

PubMed

Skoura, Evangelia; Datseris, Ioannis E; Exarhos, Dimitrios; Chatziioannou, Sophia; Oikonomopoulos, Georgios; Samartzis, Alexandros; Giannopoulou, Chariklia; Syrigos, Konstantinos N

2013-05-01

[ 18 F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been reported to have a low sensitivity in the initial diagnosis of bronchoalveolar carcinoma (BAC) due to BAC's low metabolic activity. The aim of this study was to assess the value of [ 18 F]FDG-PET/CT in the detection of BAC recurrence. Between February 2007 and September 2011, the [ 18 F]FDG-PET/CT scans that were performed on patients with known, histologically proven BAC were studied. A total of 24 [ 18 F]FDG-PET/CT scans were performed in 22 patients, including 16 males and 6 females, with a mean age of 65±9 years. Among the scans, 15 were performed to assess for possible recurrence with equivocal findings in conventional imaging methods and 9 for restaging post-therapy. In all cases conventional imaging studies (CT and MRI) were performed 5-30 days prior to PET/CT. Among the 24 [ 18 F]FDG-PET/CT scans, 18 were positive and 6 negative. Among the 15 [ 18 F]FDG-PET/CT scans performed for suspected recurrence, 34 lesions were detected and the mean maximum standardized uptake value (SUVmax) was 6.8±3.26. In nine scans, upstaging was observed, while two were in agreement with the findings of the conventional modalities. A greater number of lesions were detected in two scans and fewer lesions were detected in one, with no change in staging. Only one scan was negative. By contrast, in patients examined for restaging, there were only five lesions with a mean SUVmax of 4.86±3.18. Agreement between the findings of [ 18 F]FDG-PET/CT and the conventional modalities was observed in 8 out of 9 cases. Although [ 18 F]FDG-PET/CT has been reported to have a low sensitivity in the initial diagnosis of BAC, the present results indicate that when there is recurrence, the lesions become [ 18 F]FDG avid. [ 18 F]FDG-PET/CT may provide further information in patients evaluated for recurrence and thus improve patient management.

Reading Center Characterization of Central Retinal Vein Occlusion Using Optical Coherence Tomography During the COPERNICUS Trial.

PubMed

Decroos, Francis Char; Stinnett, Sandra S; Heydary, Cynthia S; Burns, Russell E; Jaffe, Glenn J

2013-11-01

To determine the impact of segmentation error correction and precision of standardized grading of time domain optical coherence tomography (OCT) scans obtained during an interventional study for macular edema secondary to central retinal vein occlusion (CRVO). A reading center team of two readers and a senior reader evaluated 1199 OCT scans. Manual segmentation error correction (SEC) was performed. The frequency of SEC, resulting change in central retinal thickness after SEC, and reproducibility of SEC were quantified. Optical coherence tomography characteristics associated with the need for SECs were determined. Reading center teams graded all scans, and the reproducibility of this evaluation for scan quality at the fovea and cystoid macular edema was determined on 97 scans. Segmentation errors were observed in 360 (30.0%) scans, of which 312 were interpretable. On these 312 scans, the mean machine-generated central subfield thickness (CST) was 507.4 ± 208.5 μm compared to 583.0 ± 266.2 μm after SEC. Segmentation error correction resulted in a mean absolute CST correction of 81.3 ± 162.0 μm from baseline uncorrected CST. Segmentation error correction was highly reproducible (intraclass correlation coefficient [ICC] = 0.99-1.00). Epiretinal membrane (odds ratio [OR] = 2.3, P < 0.0001), subretinal fluid (OR = 2.1, P = 0.0005), and increasing CST (OR = 1.6 per 100-μm increase, P < 0.001) were associated with need for SEC. Reading center teams reproducibly graded scan quality at the fovea (87% agreement, kappa = 0.64, 95% confidence interval [CI] 0.45-0.82) and cystoid macular edema (92% agreement, kappa = 0.84, 95% CI 0.74-0.94). Optical coherence tomography images obtained during an interventional CRVO treatment trial can be reproducibly graded. Segmentation errors can cause clinically meaningful deviation in central retinal thickness measurements; however, these errors can be corrected reproducibly in a reading center setting. Segmentation errors are common on these images, can cause clinically meaningful errors in central retinal thickness measurement, and can be corrected reproducibly in a reading center setting.

Use of magnetic tomography technology to evaluate dowel placement

DOT National Transportation Integrated Search

2005-11-01

Extensive laboratory and field evaluations were conducted under this project to evaluate the effectiveness and limitations of the MIT Scan-2 device, which uses magnetic tomography technology to evaluate the placement of metal dowel bars in concrete p...

Endoscopic optical coherence tomography: technologies and clinical applications [Invited

PubMed Central

Gora, Michalina J.; Suter, Melissa J.; Tearney, Guillermo J.; Li, Xingde

2017-01-01

In this paper, we review the current state of technology development and clinical applications of endoscopic optical coherence tomography (OCT). Key design and engineering considerations are discussed for most OCT endoscopes, including side-viewing and forward-viewing probes, along with different scanning mechanisms (proximal-scanning versus distal-scanning). Multi-modal endoscopes that integrate OCT with other imaging modalities are also discussed. The review of clinical applications of endoscopic OCT focuses heavily on diagnosis of diseases and guidance of interventions. Representative applications in several organ systems are presented, such as in the cardiovascular, digestive, respiratory, and reproductive systems. A brief outlook of the field of endoscopic OCT is also discussed. PMID:28663882

Malignant external otitis: early scintigraphic detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strashun, A.M.; Nejatheim, M.; Goldsmith, S.J.

1984-02-01

Pseudomonas otitis externa in elderly diabetics may extend aggressively to adjacent bone, cranial nerves, meninges, and vessels, leading to a clinical diagnosis of ''malignant'' external otitis. Early diagnosis is necessary for successful treatment. This study compares the findings of initial radiographs, thin-section tomography of temporal bone, CT scans of head and neck, technetium-99m methylene diphosphonate (MDP) and gallium-67 citrate scintigraphy, and single-photon emission computed tomography (SPECT) for detection of temporal bone osteomylitis in ten patients fulfilling the clinical diagnostic criteria of malignant external otitis. Skull radiographs were negative in all of the eight patients studied. Thin-section tomography was positive inmore » one of the seven patients studied using this modality. CT scanning suggested osteomyelitis in three of nine patients. Both Tc-99m and Ga-67 citrate scintigraphy were positive in 10 of 10 patients. These results suggest that technetium and gallium scintigraphy are more sensitive than radiographs and CT scans for early detection of malignant external otitis.« less

Quantification of abnormal intracranial pressure waves and isotope cisternography for diagnosis of occult communicating hydrocephalus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardoso, E.R.; Piatek, D.; Del Bigio, M.R.

1989-01-01

Nineteen consecutive patients with suspected occult communicating hydrocephalus were investigated by means of clinical evaluation, neuropsychological testing, isotope cisternography, computed tomography scanning, and continuous intracranial pressure monitoring. Semi-quantitative grading systems were used in the evaluation of the clinical, neuropsychological, and cisternographic assessments. Clinical examination, neuropsychological testing, and computed tomography scanning were repeated 3 months after ventriculoperitoneal shunting. All patients showed abnormal intracranial pressure waves and all improved after shunting. There was close correlation between number, peak, and pulse pressures of B waves and the mean intracranial pressure. However, quantification of B waves by means of number, frequency, and amplitude didmore » not help in predicting the degree of clinical improvement postshunting. The most sensitive predictor of favorable response to shunting was enlargement of the temporal horns on computed tomography scan. Furthermore, the size of temporal horns correlated with mean intracranial pressure. There was no correlation between abnormalities on isotope cisternography and clinical improvement.« less

Influence of anatomical location on CT numbers in cone beam computed tomography.

PubMed

Oliveira, Matheus L; Tosoni, Guilherme M; Lindsey, David H; Mendoza, Kristopher; Tetradis, Sotirios; Mallya, Sanjay M

2013-04-01

To assess the influence of anatomical location on computed tomography (CT) numbers in mid- and full field of view (FOV) cone beam computed tomography (CBCT) scans. Polypropylene tubes with varying concentrations of dipotassium hydrogen phosphate (K₂HPO₄) solutions (50-1200 mg/mL) were imaged within the incisor, premolar, and molar dental sockets of a human skull phantom. CBCT scans were acquired using the NewTom 3G and NewTom 5G units. The CT numbers of the K₂HPO₄ phantoms were measured, and the relationship between CT numbers and K₂HPO₄ concentration was examined. The measured CT numbers of the K₂HPO₄ phantoms were compared between anatomical sites. At all six anatomical locations, there was a strong linear relationship between CT numbers and K₂HPO₄ concentration (R(2)>0.93). However, the absolute CT numbers varied considerably with the anatomical location. The relationship between CT numbers and object density is not uniform through the dental arch on CBCT scans. Copyright © 2013 Elsevier Inc. All rights reserved.

Treatment Option Overview (Parathyroid Cancer)

MedlinePlus

... of the head and neck. SPECT scan (single photon emission computed tomography scan) : A procedure that uses ... a recurrence. The parathyroid cancer usually recurs between 2 and 5 years after the first surgery , but ...

HAADF-STEM atom counting in atom probe tomography specimens: Towards quantitative correlative microscopy.

PubMed

Lefebvre, W; Hernandez-Maldonado, D; Moyon, F; Cuvilly, F; Vaudolon, C; Shinde, D; Vurpillot, F

2015-12-01

The geometry of atom probe tomography tips strongly differs from standard scanning transmission electron microscopy foils. Whereas the later are rather flat and thin (<20 nm), tips display a curved surface and a significantly larger thickness. As far as a correlative approach aims at analysing the same specimen by both techniques, it is mandatory to explore the limits and advantages imposed by the particular geometry of atom probe tomography specimens. Based on simulations (electron probe propagation and image simulations), the possibility to apply quantitative high angle annular dark field scanning transmission electron microscopy to of atom probe tomography specimens has been tested. The influence of electron probe convergence and the benefice of deconvolution of electron probe point spread function electron have been established. Atom counting in atom probe tomography specimens is for the first time reported in this present work. It is demonstrated that, based on single projections of high angle annular dark field imaging, significant quantitative information can be used as additional input for refining the data obtained by correlative analysis of the specimen in APT, therefore opening new perspectives in the field of atomic scale tomography. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing stapes piston position using computed tomography: a cadaveric study.

PubMed

Hahn, Yoav; Diaz, Rodney; Hartman, Jonathan; Bobinski, Matthew; Brodie, Hilary

2009-02-01

Temporal bone computed tomographic (CT) scanning in the postoperative stapedotomy patient is inaccurate in assessing stapes piston position within the vestibule. Poststapedotomy patients that have persistent vertigo may undergo CT scanning to assess the position of the stapes piston within the vestibule to rule out overly deep insertion. Vertigo is a recognized complication of the deep piston, and CT evaluation is often recommended. The accuracy of CT scan in this setting is unestablished. Stapedotomy was performed on 12 cadaver ears, and stainless steel McGee pistons were placed. The cadaver heads were then scanned using a fine-cut temporal bone protocol. Temporal bone dissection was performed with microscopic measurement of the piston depth in the vestibule. These values were compared with depth of intravestibular penetration measured on CT scan by 4 independent measurements. The intravestibular penetration as assessed by computed tomography was consistently greater than the value found on cadaveric anatomic dissection. The radiographic bias was greater when piston location within the vestibule was shallower. The axial CT scan measurement was 0.53 mm greater, on average, than the anatomic measurement. On average, the coronal CT measurement was 0.68 mm greater than the anatomic measurement. The degree of overestimation of penetration, however, was highly inconsistent. Standard temporal bone CT scan is neither an accurate nor precise examination of stapes piston depth within the vestibule. We found that CT measurement consistently overstated intravestibular piston depth. Computed tomography is not a useful study in the evaluation of piston depth for poststapedectomy vertigo and is of limited value in this setting.

Radiation dose to radiosensitive organs in PET/CT myocardial perfusion examination using versatile optical fibre

NASA Astrophysics Data System (ADS)

Salasiah, M.; Nordin, A. J.; Fathinul Fikri, A. S.; Hishar, H.; Tamchek, N.; Taiman, K.; Ahmad Bazli, A. K.; Abdul-Rashid, H. A.; Mahdiraji, G. A.; Mizanur, R.; Noor, Noramaliza M.

2013-05-01

Cardiac positron emission tomography (PET) provides a precise method in order to diagnose obstructive coronary artery disease (CAD), compared to single photon emission tomography (SPECT). PET is suitable for obese and patients who underwent pharmacologic stress procedures. It has the ability to evaluate multivessel coronary artery disease by recording changes in left ventricular function from rest to peak stress and quantifying myocardial perfusion (in mL/min/g of tissue). However, the radiation dose to the radiosensitive organs has become crucial issues in the Positron Emission Tomography/Computed Tomography(PET/CT) scanning procedure. The objective of this study was to estimate radiation dose to radiosensitive organs of patients who underwent PET/CT myocardial perfusion examination at Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia in one month period using versatile optical fibres (Ge-B-doped Flat Fibre) and LiF (TLD-100 chips). All stress and rest paired myocardial perfusion PET/CT scans will be performed with the use of Rubidium-82 (82Rb). The optic fibres were loaded into plastic capsules and attached to patient's eyes, thyroid and breasts prior to the infusion of 82Rb, to accommodate the ten cases for the rest and stress PET scans. The results were compared with established thermoluminescence material, TLD-100 chips. The result shows that radiation dose given by TLD-100 and Germanium-Boron-doped Flat Fiber (Ge-B-doped Flat Fiber) for these five organs were comparable to each other where the p>0.05. For CT scans,thyroid received the highest dose compared to other organs. Meanwhile, for PET scans, breasts received the highest dose.

3D chemical mapping: application of scanning transmission (soft) X-ray microscopy (STXM) in combination with angle-scan tomography in bio-, geo-, and environmental sciences.

PubMed

Obst, Martin; Schmid, Gregor

2014-01-01

The identification of environmental processes and mechanisms often requires information on the organochemical and inorganic composition of specimens at high spatial resolution. X-ray spectroscopy (XAS) performed in the soft X-ray range (100-2,200 eV) provides chemical speciation information for elements that are of high biogeochemical relevance such as carbon, nitrogen, and oxygen but also includes transition metals such as iron, manganese, or nickel. Synchrotron-based scanning transmission X-ray microscopy (STXM) combines XAS with high resolution mapping on the 20-nm scale. This provides two-dimensional (2D) quantitative information about the distribution of chemical species such as organic macromolecules, metals, or mineral phases within environmental samples. Furthermore, the combination of STXM with angle-scan tomography allows for three-dimensional (3D) spectromicroscopic analysis of bio-, geo-, or environmental samples. For the acquisition of STXM tomography data, the sample is rotated around an axis perpendicular to the X-ray beam. Various sample preparation approaches such as stripes cut from TEM grids or the preparation of wet cells allow for preparing environmentally relevant specimens in a dry or in a fully hydrated state for 2D and 3D STXM measurements. In this chapter we give a short overview about the principles of STXM, its application to environmental sciences, different preparation techniques, and the analysis and 3D reconstruction of STXM tomography data.

Few CT Scan Abnormalities Found Even in Neurologically Impaired Learning Disabled Children.

ERIC Educational Resources Information Center

Denckla, Martha Bridge; And Others

1985-01-01

Most of 32 learning disabled children (seven to 14 years old) with neurological lateralization characteristics marked by right and left hemispheres had a normal CT (computerized tomography) scan. (CL)

SPECT (Single-Photon Emission Computerized Tomography) Scan

MedlinePlus

... can become damaged or even die. Reduced pumping efficiency. SPECT can show how completely your heart chambers ... radioactive tracer SPECT scans aren't safe for women who are pregnant or breast-feeding because the ...

Non-Hodgkin Lymphoma (For Parents)

MedlinePlus

... chest X-ray a computerized tomography (CT or CAT) scan , which rotates around the patient and creates an ... ray (Video) Getting an MRI (Video) Getting a CAT Scan (Video) Chemotherapy Hodgkin Lymphoma Stem Cell Transplants Can ...

Computed Tomography (CT) Scans and Cancer

MedlinePlus

... an imaging procedure that uses special x-ray equipment to create detailed pictures, or scans, of areas ... at the center ( 10 ). In addition, all imaging equipment purchased by NIH must provide data on exposure ...

Reduction of speckle noise from optical coherence tomography images using multi-frame weighted nuclear norm minimization method

NASA Astrophysics Data System (ADS)

Thapa, Damber; Raahemifar, Kaamran; Lakshminarayanan, Vasudevan

2015-12-01

In this paper, we propose a speckle noise reduction method for spectral-domain optical coherence tomography (SD-OCT) images called multi-frame weighted nuclear norm minimization (MWNNM). This method is a direct extension of weighted nuclear norm minimization (WNNM) in the multi-frame framework since an adequately denoised image could not be achieved with single-frame denoising methods. The MWNNM method exploits multiple B-scans collected from a small area of a SD-OCT volumetric image, and then denoises and averages them together to obtain a high signal-to-noise ratio B-scan. The results show that the image quality metrics obtained by denoising and averaging only five nearby B-scans with MWNNM method is considerably better than those of the average image obtained by registering and averaging 40 azimuthally repeated B-scans.

Cone Beam X-Ray Luminescence Tomography Imaging Based on KA-FEM Method for Small Animals.

PubMed

Chen, Dongmei; Meng, Fanzhen; Zhao, Fengjun; Xu, Cao

2016-01-01

Cone beam X-ray luminescence tomography can realize fast X-ray luminescence tomography imaging with relatively low scanning time compared with narrow beam X-ray luminescence tomography. However, cone beam X-ray luminescence tomography suffers from an ill-posed reconstruction problem. First, the feasibility of experiments with different penetration and multispectra in small animal has been tested using nanophosphor material. Then, the hybrid reconstruction algorithm with KA-FEM method has been applied in cone beam X-ray luminescence tomography for small animals to overcome the ill-posed reconstruction problem, whose advantage and property have been demonstrated in fluorescence tomography imaging. The in vivo mouse experiment proved the feasibility of the proposed method.

Real-time optical coherence tomography observation of retinal tissue damage during laser photocoagulation therapy on ex-vivo porcine samples

NASA Astrophysics Data System (ADS)

Steiner, P.; Považay, B.; Stoller, M.; Morgenthaler, P.; Inniger, D.; Arnold, P.; Sznitman, R.; Meier, Ch.

2015-07-01

Retinal laser photocoagulation represents a widely used treatment for retinal pathologies such as diabetic chorioretinopathy or diabetic edema. For effective treatment, an appropriate choice of the treatment energy dose is crucial to prevent excessive tissue damage caused by over-irradiation of the retina. In this manuscript we investigate simultaneous and time-resolved optical coherence tomography for its applicability to provide feedback to the ophthalmologist about the introduced retinal damage during laser photocoagulation. Time-resolved and volumetric optical coherence tomography data of 96 lesions on ex-vivo porcine samples, set with a 577 nm laser prototype and irradiance of between 300 and 8800 W=cm2 were analyzed. Time-resolved scans were compared to volumetric scans of the lesion and correlated with ophthalmoscopic visibility. Lastly, image parameters extracted from optical coherence tomography Mscans, suitable for lesion classification were identified. Results presented in this work support the hypothesis that simultaneous optical coherence tomography provides valuable information about the extent of retinal tissue damage and may be used to guide retinal laser photocoagulation in the future.

SU-E-E-11: Novel Matching Module for Respiration-Gated Motion Tumor of Cone-Beam Computed Tomography (CBCT) to 4DCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, P; Tsai, Y; Nien, H

2015-06-15

Purpose: Four dimensional computed tomography (4DCT) scans reliably record whole respiratory phase and generate internal target volumes (ITV) for radiotherapy planning. However, image guiding with cone-beam computed tomography (CBCT) cannot acquire all or specific respiratory phases. This study was designed to investigate the correlation between average CT and Maximum Intensity Projection (MIP) from 4DCT and CBCT. Methods: Retrospective respiratory gating were performed by GE Discovery CT590 RT. 4DCT and CBCT data from CRIS Dynamic Thorax Phantom with simulated breathing mode were analyzed. The lung tissue equivalent material encompassed 3 cm sphere tissue equivalent material. Simulated breathing cycle period was setmore » as 4 seconds, 5 seconds and 6 seconds for representing variation of patient breathing cycle time, and the sphere material moved toward inferior and superior direction with 1 cm amplitude simulating lung tumor motion during respiration. Results: Under lung window, the volume ratio of CBCT scans to ITVs derived from 10 phases average scans was 1.00 ± 0.02, and 1.03 ± 0.03 for ratio of CBCT scans to MIP scans. Under abdomen window, the ratio of CBCT scans to ITVs derived from 10 phases average scans was 0.39 ± 0.06, and 0.06 ± 0.00 for ratio of CBCT scans to MIP scans. There was a significant difference between lung window Result and abdomen window Result. For reducing image guiding uncertainty, CBCT window was set with width 500 and level-250. The ratio of CBCT scans to ITVs derived from 4 phases average scans with abdomen window was 1.19 ± 0.02, and 1.06 ± 0.01 for ratio of CBCT to MIP scans. Conclusion: CBCT images with suitable window width and level can efficiently reduce image guiding uncertainty for patient with mobile tumor. By our setting, we can match motion tumor to gating tumor location on planning CT more accurately neglecting other motion artifacts during CBCT scans.« less

Concussion

MedlinePlus

... symptoms. They may test your senses, balance, reflexes, memory, and thinking. In some cases, the doctor will order tests to scan your brain. These include a computed tomography (CT) or magnetic resonance imaging (MRI) scan. They take a picture of your ...

Multi-contrast imaging of human posterior eye by Jones matrix optical coherence tomography

NASA Astrophysics Data System (ADS)

Yasuno, Yoshiaki

2017-04-01

A multi-contrast imaging of pathologic posterior eyes is demonstrated by Jones matrix optical coherence tomography (Jones matrix OCT). The Jones matrix OCT provides five tomographies, which includes scattering, local attenuation, birefringence, polarization uniformity, and optical coherence angiography, by a single scan. The hardware configuration, algorithms of the Jones matrix OCT as well as its application to ophthalmology is discussed.

Just Scan It!-Weapon Reconstruction in Computed Tomography on Historical and Current Swiss Military Guns.

PubMed

Franckenberg, Sabine; Binder, Thomas; Bolliger, Stephan; Thali, Michael J; Ross, Steffen G

2016-09-01

Cross-sectional imaging, such as computed tomography, has been increasingly implemented in both historic and recent postmortem forensic investigations. It aids in determining cause and manner of death as well as in correlating injuries to possible weapons. This study illuminates the feasibility of reconstructing guns in computed tomography and gives a distinct overview of historic and recent Swiss Army guns.

Whole-cell imaging of the budding yeast Saccharomyces cerevisiae by high-voltage scanning transmission electron tomography.

PubMed

Murata, Kazuyoshi; Esaki, Masatoshi; Ogura, Teru; Arai, Shigeo; Yamamoto, Yuta; Tanaka, Nobuo

2014-11-01

Electron tomography using a high-voltage electron microscope (HVEM) provides three-dimensional information about cellular components in sections thicker than 1 μm, although in bright-field mode image degradation caused by multiple inelastic scattering of transmitted electrons limit the attainable resolution. Scanning transmission electron microscopy (STEM) is believed to give enhanced contrast and resolution compared to conventional transmission electron microscopy (CTEM). Samples up to 1 μm in thickness have been analyzed with an intermediate-voltage electron microscope because inelastic scattering is not a critical limitation, and probe broadening can be minimized. Here, we employed STEM at 1 MeV high-voltage to extend the useful specimen thickness for electron tomography, which we demonstrate by a seamless tomographic reconstruction of a whole, budding Saccharomyces cerevisiae yeast cell, which is ~3 μm in thickness. High-voltage STEM tomography, especially in the bright-field mode, demonstrated sufficiently enhanced contrast and intensity, compared to CTEM tomography, to permit segmentation of major organelles in the whole cell. STEM imaging also reduced specimen shrinkage during tilt-series acquisition. The fidelity of structural preservation was limited by cytoplasmic extraction, and the spatial resolution was limited by the relatively large convergence angle of the scanning probe. However, the new technique has potential to solve longstanding problems of image blurring in biological specimens beyond 1 μm in thickness, and may facilitate new research in cellular structural biology. Copyright © 2014 Elsevier B.V. All rights reserved.

A Computerized Wear Particle Atlas for Ferrogram and Filtergram Analyses

DTIC Science & Technology

1998-01-01

A Computerised Wear Particle Atlas for Ferrogram and Filtergram Analyses Jian G. Ding Lubrosoft P/L P 0 Box 2368, Rowville Melbourne VIC 3178...Australia (61-3) 9759-9083 Abstract: A new computerised wear particle atlas has been developed for identification of solid particles and...differentiation of wear severity of lubricated equipment. This atlas contains 892 images of representative solid particles selected from thousands of filtergram

Digital holographic tomography based on spectral interferometry.

PubMed

Yu, Lingfeng; Chen, Zhongping

2007-10-15

A digital holographic tomography system has been developed with the use of an inexpensive broadband light source and a fiber-based spectral interferometer. Multiple synthesized holograms (or object wave fields) of different wavelengths are obtained by transversely scanning a probe beam. The acquisition speed is improved compared with conventional wavelength-scanning digital holographic systems. The optical field of a volume around the object location is calculated by numerical diffraction from each synthesized hologram, and all such field volumes are numerically superposed to create the three-dimensional tomographic image. Experiments were performed to demonstrate the idea.

Use of optical coherence topography for objective assessment of fundus torsion.

PubMed

Sophocleous, Sophocles

2017-02-23

Objective assessment of fundus torsion is currently performed with indirect ophthalmoscopy or fundus photography. Using the infrared image of the macular scan of the optical coherence tomography one can assess the presence and amount of fundus torsion. In addition, the line scan through the fovea can be used as a reference to confirm the position of the foveal pit in relation to the optic nerve head. Two cases are used to demonstrate how to assess fundus torsion with the use of the optical coherence tomography. 2017 BMJ Publishing Group Ltd.

Computed tomography of orbital tumors in the dog.

PubMed

LeCouteur, R A; Fike, J R; Scagliotti, R H; Cann, C E

1982-04-15

Computed tomography (CT) was used to investigate orbital tumors in 3 dogs. Tumors were clearly defined on transverse CT scans by their inherent density and gross distortion of normal orbital anatomy. Dorsal images synthesized from the original transverse scans were also used to visualize size and extent of tumors. Use of an iodinated contrast medium did not appear to improve localization of tumors in the orbit but was useful for identification of tumor extension into the calvaria. It was concluded that CT offered advantages over existing methods of radiographic diagnosis of orbital tumors and exophthalmos.

A systematic review of computerised serious educational games about alcohol and other drugs for adolescents.

PubMed

Rodriguez, Daniel M; Teesson, Maree; Newton, Nicola C

2014-03-01

Serious educational games (SEG) have been shown to be effective in educating young people about a range of topics, including languages and maths. This paper identifies the use of computerised SEGs in education about alcohol and other drugs and reviews their impact on the prevention of alcohol and drug use. The Cochrane Library, EMBASE, MEDLINE, ERIC, Scopus, psychINFO, pubMED and DRUG databases were searched in February 2013. Additional publications were obtained from the reference lists of the relevant papers. Studies were included if they described an evaluation of a computerised SEG that targeted alcohol and/or other drugs and had been trialled with adolescents. Eight SEGs were identified targeting tobacco, alcohol, cannabis, methamphetamine, ecstasy, inhalants, cocaine and opioids. Six reported positive outcomes in terms of increased content knowledge and two reported increased negative attitudes towards the targeted drugs. Only one reported a decrease in the frequency of drug use. This is the first review of the efficacy of computerised SEGs for alcohol and other drugs for adolescents. Results suggest that SEGs can increase content knowledge of alcohol and other drugs. Evidence concerning impacts on negative attitudes and alcohol and drug use is limited, with few studies examining these outcomes. © 2013 Australasian Professional Society on Alcohol and other Drugs.

Feasibility and effectiveness of a cognitive remediation programme with original computerised cognitive training and group intervention for schizophrenia: a multicentre randomised trial.

PubMed

Matsuda, Yasuhiro; Morimoto, Tsubasa; Furukawa, Shunichi; Sato, Sayaka; Hatsuse, Norifumi; Iwata, Kazuhiko; Kimura, Mieko; Kishimoto, Toshifumi; Ikebuchi, Emi

2018-04-01

Devising new methods to improve neurocognitive impairment through cognitive remediation is an important research goal. We developed an original computer programme termed the Japanese Cognitive Rehabilitation Programme for Schizophrenia (JCORES) that provides cognitive practice across a broad range of abilities. The current study examined for the first time whether a cognitive remediation programme, including both computerised cognitive training using JCORES and group intervention such as enhancing meta-cognition and teaching strategies, is more effective than treatment as usual for improving neurocognitive and social functioning. Sixty-two outpatients with schizophrenia were randomised to either a cognitive remediation group or a control group. Participants engaged in two computerised cognitive training sessions and one group meeting per week for 12 weeks. The average number of total sessions attended (computerised cognitive practice + group intervention) was 32.3 (89.7%). The cognitive remediation group showed significantly more improvements in verbal memory, composite score of the Brief Assessment of Cognition in Schizophrenia, Japanese version (BACS-J), and general psychopathology on the Positive and Negative Syndrome Scale (PANSS) than the control group. These findings demonstrate that a cognitive remediation programme is feasible in Japan and is a more effective way to improve neurocognitive functioning and psychiatric symptoms.

Using three-dimensional-computerized tomography as a diagnostic tool for temporo-mandibular joint ankylosis: a case report.

PubMed

Kao, S Y; Chou, J; Lo, J; Yang, J; Chou, A P; Joe, C J; Chang, R C

1999-04-01

Roentgenographic examination has long been a useful diagnostic tool for temporo-mandibular joint (TMJ) disease. The methods include TMJ tomography, panoramic radiography and computerized tomography (CT) scan with or without injection of contrast media. Recently, three-dimensional CT (3D-CT), reconstructed from the two-dimensional image of a CT scan to simulate the soft tissue or bony structure of the real target, was proposed. In this report, a case of TMJ ankylosis due to traumatic injury is presented. 3D-CT was employed as one of the presurgical roentgenographic diagnostic tools. The conventional radiographic examination including panoramic radiography and tomography showed lesions in both sides of the mandible. CT scanning further suggested that the right-sided lesion was more severe than that on the left. With 3D-CT image reconstruction the size and extent of the lesions were clearly observable. The decision was made to proceed with an initial surgical approach on the right side. With condylectomy and condylar replacement using an autogenous costochondral graft on the right side, the range of mouth opening improved significantly. In this case report, 3D-CT demonstrates its advantages as a tool for the correct and precise diagnosis of TMJ ankylosis.

Standardization and Optimization of Computed Tomography Protocols to Achieve Low-Dose

PubMed Central

Chin, Cynthia; Cody, Dianna D.; Gupta, Rajiv; Hess, Christopher P.; Kalra, Mannudeep K.; Kofler, James M.; Krishnam, Mayil S.; Einstein, Andrew J.

2014-01-01

The increase in radiation exposure due to CT scans has been of growing concern in recent years. CT scanners differ in their capabilities and various indications require unique protocols, but there remains room for standardization and optimization. In this paper we summarize approaches to reduce dose, as discussed in lectures comprising the first session of the 2013 UCSF Virtual Symposium on Radiation Safety in Computed Tomography. The experience of scanning at low dose in different body regions, for both diagnostic and interventional CT procedures, is addressed. An essential primary step is justifying the medical need for each scan. General guiding principles for reducing dose include tailoring a scan to a patient, minimizing scan length, use of tube current modulation and minimizing tube current, minimizing-tube potential, iterative reconstruction, and periodic review of CT studies. Organized efforts for standardization have been spearheaded by professional societies such as the American Association of Physicists in Medicine. Finally, all team members should demonstrate an awareness of the importance of minimizing dose. PMID:24589403

Incidental findings on computed tomography scans in children with mild head trauma.

PubMed

Ortega, Henry W; Vander Velden, Heidi; Reid, Samuel

2012-09-01

Computed tomography (CT) scans are frequently used in managing traumatic brain injuries in children. To assess incidental findings in children with head trauma undergoing CT scan and to describe any associated clinical ramifications. Retrospective review of 524 children treated in 2 emergency departments for closed head injury who received a CT scan. Overall, 137 (26.2%) patients had an incidental finding on CT scan. The most common incidental finding was sinus opacification with an air fluid level (115/137, 83.9%). Thirty-five interventions were reported in children with incidental findings. Children 2 years old or younger were more likely to receive a prescription for antibiotics (relative risk [RR] = 2.66, 95% confidence interval [CI] = 1.08-6.51) and be referred to a specialist (RR = 10.26, 95% CI = 3.56-29.56) than older children. Incidental findings in minor head trauma are common. Clinicians should be prepared to address these findings if clinically indicated.

MR/PET Imaging of the Cardiovascular System.

PubMed

Robson, Philip M; Dey, Damini; Newby, David E; Berman, Daniel; Li, Debiao; Fayad, Zahi A; Dweck, Marc R

2017-10-01

Cardiovascular imaging has largely focused on identifying structural, functional, and metabolic changes in the heart. The ability to reliably assess disease activity would have major potential clinical advantages, including the identification of early disease, differentiating active from stable conditions, and monitoring disease progression or response to therapy. Positron emission tomography (PET) imaging now allows such assessments of disease activity to be acquired in the heart, whereas magnetic resonance (MR) scanning provides detailed anatomic imaging and tissue characterization. Hybrid MR/PET scanners therefore combine the strengths of 2 already powerful imaging modalities. Simultaneous acquisition of the 2 scans also provides added benefits, including improved scanning efficiency, motion correction, and partial volume correction. Radiation exposure is lower than with hybrid PET/computed tomography scanning, which might be particularly beneficial in younger patients who may need repeated scans. The present review discusses the expanding clinical literature investigating MR/PET imaging, highlights its advantages and limitations, and explores future potential applications. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Bessel beam fluorescence lifetime tomography of live embryos (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Dongli; Peng, Leilei

2016-03-01

Optical tomography allows isotropic 3D imaging of embryos. Scanning-laser optical tomography (SLOT) has superior light collecting efficiency than wide-field optical tomography, making it ideal for fluorescence imaging of live embryos. We previously reported an imaging system that combines SLOT with a novel Fourier-multiplexed fluorescence lifetime imaging (FmFLIM) technique named FmFLIM-SLOT. FmFLIM-SLOT performs multiplexed FLIM-FRET readout of multiple FRET sensors in live embryos. Here we report a recent effort on improving the spatial resolution of the FmFLIM-SLOT system in order to image complex biochemical processes in live embryos at the cellular level. Optical tomography has to compromise between resolution and the depth of view. In SLOT, the commonly-used focused Gaussian beam diverges quickly from the focal plane, making it impossible to achieve high resolution imaging in a large volume specimen. We thus introduce Bessel beam laser-scanning tomography, which illuminates the sample with a spatial-light-modulator-generated Bessel beam that has an extended focal depth. The Bessel beam is scanned across the whole specimen. Fluorescence projection images are acquired at equal angular intervals as the sample rotates. Reconstruction artifacts due to annular-rings of the Bessel beam are removed by a modified 3D filtered back projection algorithm. Furthermore, in combination of Fourier-multiplexing fluorescence lifetime imaging (FmFLIM) method, the Bessel FmFLIM-SLOT system is capable of perform 3D lifetime imaging of live embryos at cellular resolution. The system is applied to in-vivo imaging of transgenic Zebrafish embryos. Results prove that Bessel FmFLIM-SLOT is a promising imaging method in development biology research.

Computed tomography-assisted laparoscopic removal of intraabdominally migrated levonorgestrel-releasing intrauterine systems.

PubMed

Mahmoud, Mohamad S; Merhi, Zaher O

2010-04-01

To report three cases of migrated levonorgestrel intrauterine device (LNG-IUS) into the pelvic/abdominal cavity removed laparoscopically with the aid of preoperative computed tomography (CT) scan imaging. Three patients presenting with a missing LNG-IUS on examination and pelvic ultrasound are presented. A preoperative CT scan was performed, what helped in a successful removal of the LNG-IUS. The patients were discharged home the same day of the procedure. Our cases reinforce, besides the diagnosis of a migrated LNG-IUS by ultrasound, the fact that preoperative CT scan imaging assists in the diagnosis of the precise location of a migrated LNG-IUS into the pelvic/abdominal cavity and helps the physician in the prediction of the difficulty of the laparoscopic removal.

PET scan-positive cat scratch disease in a patient with T cell lymphoblastic lymphoma.

PubMed

Jeong, Woondong; Seiter, Karen; Strauchen, James; Rafael, Theodore; Lau, Har Chi; Breakstone, Beth; Ahmed, Tauseef; Liu, Delong

2005-05-01

In patients who have history of lymphoma, a positive positron emission tomography (PET) scan is frequently considered as good evidence for relapse and/or persistent disease. Thus, lymph node biopsy is not always done to confirm the diagnosis of relapse or refractory lymphoma before a patient is subjected to further chemotherapy. We report a case of patient with history of T cell lymphoblastic lymphoma who presented again with inguinal lymphadenopathy and positive study on positron emission tomography suggestive of lymphoma relapse. This was pathologically proven to be cat scratch disease. This case suggests that in the immunocompromised patients who had history of lymphoma, infectious etiology should be ruled out for PET scan-positive lymphadenopathy.

Enabling freehand lateral scanning of optical coherence tomography needle probes with a magnetic tracking system

PubMed Central

Yeo, Boon Y.; McLaughlin, Robert A.; Kirk, Rodney W.; Sampson, David D.

2012-01-01

We present a high-resolution three-dimensional position tracking method that allows an optical coherence tomography (OCT) needle probe to be scanned laterally by hand, providing the high degree of flexibility and freedom required in clinical usage. The method is based on a magnetic tracking system, which is augmented by cross-correlation-based resampling and a two-stage moving window average algorithm to improve upon the tracker's limited intrinsic spatial resolution, achieving 18 µm RMS position accuracy. A proof-of-principle system was developed, with successful image reconstruction demonstrated on phantoms and on ex vivo human breast tissue validated against histology. This freehand scanning method could contribute toward clinical implementation of OCT needle imaging. PMID:22808429

The Selection of Computed Tomography Scanning Schemes for Lengthy Symmetric Objects

NASA Astrophysics Data System (ADS)

Trinh, V. B.; Zhong, Y.; Osipov, S. P.

2017-04-01

. The article describes the basic computed tomography scan schemes for lengthy symmetric objects: continuous (discrete) rotation with a discrete linear movement; continuous (discrete) rotation with discrete linear movement to acquire 2D projection; continuous (discrete) linear movement with discrete rotation to acquire one-dimensional projection and continuous (discrete) rotation to acquire of 2D projection. The general method to calculate the scanning time is discussed in detail. It should be extracted the comparison principle to select a scanning scheme. This is because data are the same for all scanning schemes: the maximum energy of the X-ray radiation; the power of X-ray radiation source; the angle of the X-ray cone beam; the transverse dimension of a single detector; specified resolution and the maximum time, which is need to form one point of the original image and complies the number of registered photons). It demonstrates the possibilities of the above proposed method to compare the scanning schemes. Scanning object was a cylindrical object with the mass thickness is 4 g/cm2, the effective atomic number is 15 and length is 1300 mm. It analyzes data of scanning time and concludes about the efficiency of scanning schemes. It examines the productivity of all schemes and selects the effective one.

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

PubMed

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

2016-04-01

Channelized Hotelling observer (CHO) models have been shown to correlate well with human observers for several phantom-based detection/classification tasks in clinical computed tomography (CT). A large number of repeated scans were used to achieve an accurate estimate of the model's template. The purpose of this study is to investigate how the experimental and CHO model parameters affect the minimum required number of repeated scans. A phantom containing 21 low-contrast objects was scanned on a 128-slice CT scanner at three dose levels. Each scan was repeated 100 times. For each experimental configuration, the low-contrast detectability, quantified as the area under receiver operating characteristic curve, [Formula: see text], was calculated using a previously validated CHO with randomly selected subsets of scans, ranging from 10 to 100. Using [Formula: see text] from the 100 scans as the reference, the accuracy from a smaller number of scans was determined. Our results demonstrated that the minimum number of repeated scans increased when the radiation dose level decreased, object size and contrast level decreased, and the number of channels increased. As a general trend, it increased as the low-contrast detectability decreased. This study provides a basis for the experimental design of task-based image quality assessment in clinical CT using CHO.

Impact of number of repeated scans on model observer performance for a low-contrast detection task in computed tomography

PubMed Central

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

2016-01-01

Abstract. Channelized Hotelling observer (CHO) models have been shown to correlate well with human observers for several phantom-based detection/classification tasks in clinical computed tomography (CT). A large number of repeated scans were used to achieve an accurate estimate of the model’s template. The purpose of this study is to investigate how the experimental and CHO model parameters affect the minimum required number of repeated scans. A phantom containing 21 low-contrast objects was scanned on a 128-slice CT scanner at three dose levels. Each scan was repeated 100 times. For each experimental configuration, the low-contrast detectability, quantified as the area under receiver operating characteristic curve, Az, was calculated using a previously validated CHO with randomly selected subsets of scans, ranging from 10 to 100. Using Az from the 100 scans as the reference, the accuracy from a smaller number of scans was determined. Our results demonstrated that the minimum number of repeated scans increased when the radiation dose level decreased, object size and contrast level decreased, and the number of channels increased. As a general trend, it increased as the low-contrast detectability decreased. This study provides a basis for the experimental design of task-based image quality assessment in clinical CT using CHO. PMID:27284547

Rationale and Application of Tangential Scanning to Industrial Inspection of Hardwood Logs

Treesearch

Nand K. Gupta; Daniel L. Schmoldt; Bruce Isaacson

1998-01-01

Industrial computed tomography (CT) inspection of hardwood logs has some unique requirements not found in other CT applications. Sawmill operations demand that large volumes of wood be scanned quickly at high spatial resolution for extended duty cycles. Current CT scanning geometries and commercial systems have both technical and economic [imitations. Tangential...

Model PET Scan Activity

ERIC Educational Resources Information Center

Strunk, Amber; Gazdovich, Jennifer; Redouté, Oriane; Reverte, Juan Manuel; Shelley, Samantha; Todorova, Vesela

2018-01-01

This paper provides a brief introduction to antimatter and how it, along with other modern physics topics, is utilized in positron emission tomography (PET) scans. It further describes a hands-on activity for students to help them gain an understanding of how PET scans assist in detecting cancer. Modern physics topics provide an exciting way to…

In vivo size and shape measurement of the human upper airway using endoscopic longrange optical coherence tomography

NASA Astrophysics Data System (ADS)

Armstrong, Julian J.; Leigh, Matthew S.; Walton, Ian D.; Zvyagin, Andrei V.; Alexandrov, Sergey A.; Schwer, Stefan; Sampson, David D.; Hillman, David R.; Eastwood, Peter R.

2003-07-01

We describe a long-range optical coherence tomography system for size and shape measurement of large hollow organs in the human body. The system employs a frequency-domain optical delay line of a configuration that enables the combination of high-speed operation with long scan range. We compare the achievable maximum delay of several delay line configurations, and identify the configurations with the greatest delay range. We demonstrate the use of one such long-range delay line in a catheter-based optical coherence tomography system and present profiles of the human upper airway and esophagus in vivo with a radial scan range of 26 millimeters. Such quantitative upper airway profiling should prove valuable in investigating the pathophysiology of airway collapse during sleep (obstructive sleep apnea).

Multi-slice computed tomography 5-minute delayed scan is superior to immediate scan after contrast media application in characterization of intracranial tuberculosis.

PubMed

Hou, Dailun; Qu, Huifang; Zhang, Xu; Li, Ning; Liu, Cheng; Ma, Xiangxing

2014-09-02

The aim of this study was to determine whether the diagnosis of intracranial tuberculosis (TB) can be improved when multi-slice computed tomography (MSCT) scans are taken with a 5-min delay after contrast media application. Pre- and post-contrast CT scans of the head were obtained from 30 patients using a 16-slice spiral CT. Dual-phase acquisition was performed immediately and 5 min after contrast agent injection. Diagnostic values of different images were compared using a scoring system applied by 2 experienced radiologists. We found 526 lesions in 30 patients, including 22 meningeal thickenings, 235 meningeal tuberculomas/tubercles, and 269 parenchymal tuberculomas/tubercles. Images obtained with 5-min delayed scan time were superior in terms of lesion size and meningeal thickening outlining in all disease types (P<0.01). The ability to distinguish between vascular sections from the cerebral sulcus and tubercle was also improved (P<0.01). Image acquisition with 5-min delay after contrast agent injection should be performed as a standard scanning protocol to diagnose intracranial TB.

[Description of latest generation equipment in external radiotherapy].

PubMed

Pellejero, S; Lozares, S; Mañeru, F

2009-01-01

Both the planning systems and the form of administering radiotherapy have changed radically since the introduction of 3D planning. At present treatment planning based on computerised axial tomography (CAT) images is standard practice in radiotherapy services. In recent years lineal accelerators for medical use have incorporated technology capable of administering intensity modulated radiation beams (IMRT). With this mode distributions of conformed doses are generated that adjust to the three dimensional form of the white volume, providing appropriate coverage and a lower dose to nearby risk organs. The use of IMRT is rapidly spreading amongst radiotherapy centres throughout the world. This growing use of IMRT has focused attention on the need for greater control of the geometric uncertainties in positioning the patient and control of internal movements. To this end, both flat and volumetric image systems have been incorporated into the treatment equipment, making image-guided radiotherapy (IGRT) possible. This article offers a brief description of the latest advances included in the planning and administration of radiotherapy treatment.

Update in mild traumatic brain injury.

PubMed

Freire-Aragón, María Dolores; Rodríguez-Rodríguez, Ana; Egea-Guerrero, Juan José

2017-08-10

There has been concern for many years regarding the identification of patients with mild traumatic brain injury (TBI) at high risk of developing an intracranial lesion (IL) that would require neurosurgical intervention. The small percentage of patients with these characteristics and the exceptional mortality associated with mild TBI with IL have led to the high use of resources such as computerised tomography (CT) being reconsidered. The various protocols developed for the management of mild TBI are based on the identification of risk factors for IL, which ultimately allows more selective indication or discarding both the CT application and the hospital stay for neurological monitoring. Finally, progress in the study of brain injury biomarkers with prognostic utility in different clinical categories of TBI has recently been incorporated by several clinical practice guidelines, which has allowed, together with clinical assessment, a more accurate prognostic approach for these patients to be established. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Determinants of change in body weight and body fat distribution over 5.5 years in a sample of free-living black South African women.

PubMed

Chantler, Sarah; Dickie, Kasha; Micklesfield, Lisa K; Goedecke, Julia H

To identify socio-demographic and lifestyle determinants of weight gain in a sample of premenopasual black South African (SA) women. Changes in body composition (dual-energy X-ray absorptiometry, computerised tomography), socio-economic status (SES) and behavioural/lifestyle factors were measured in 64 black SA women at baseline (27 ± 8 years) and after 5.5 years. A lower body mass index (BMI) and nulliparity, together with access to sanitation, were significant determinants of weight gain and change in body fat distribution over 5.5 years. In addition, younger women increased their body weight more than their older counterparts, but this association was not independent of other determinants. Further research is required to examine the effect of changing SES, as well as the full impact of childbearing on weight gain over time in younger women with lower BMIs. This information will suggest areas for possible intervention to prevent long-term weight gain in these women.

Esophageal tuberculosis presenting with hematemesis

PubMed Central

Jain, Samit S; Somani, Piyush O; Mahey, Rajeshkumar C; Shah, Dharmesh K; Contractor, Qais Q; Rathi, Pravin M

2013-01-01

Esophageal tuberculosis is rare, constituting about 0.3% of gastrointestinal tuberculosis. It presents commonly with dysphagia, cough, chest pain in addition to fever and weight loss. Complications may include hemorrhage from the lesion, development of arterioesophageal fistula, esophagocutaneous fistula or tracheoesophageal fistula. There are very few reports of esophageal tuberculosis presenting with hematemesis due to ulceration. We report a patient with hematemesis that was due to the erosion of tuberculous subcarinal lymph nodes into the esophagus. A 15-year-old boy presented with hemetemesis as his only complaint. Esophagogastroduodenoscopy (EGD) revealed an eccentric ulcerative lesion involving 50% of circumference of the esophagus. Biopsy showed caseating epitheloid granulomas with lymphocytic infiltrates suggestive of tuberculosis. Computerised tomography of the thorax revealed thickening of the mid-esophagus with enlarged mediastinal lymph nodes in the subcarinal region compressing the esophagus along with moderate right sided pleural effusion. Patient was treated with anti-tuberculosis therapy (Rifampicin, Isoniazid, Pyrazinamide, Ethambutol) for 6 mo. Repeat EGD showed scarring and mucosal tags with complete resolution of the esophageal ulcer. PMID:24255751

What is Aphasia? | NIH MedlinePlus the Magazine

MedlinePlus

... of aphasia while treating the patient for a brain injury. To diagnose aphasia, the clinician will usually order ... a computed tomography (CT) scan to locate a brain injury. In addition to the scans, the clinician usually ...

Modern technologies for retinal scanning and imaging: an introduction for the biomedical engineer

PubMed Central

2014-01-01

This review article is meant to help biomedical engineers and nonphysical scientists better understand the principles of, and the main trends in modern scanning and imaging modalities used in ophthalmology. It is intended to ease the communication between physicists, medical doctors and engineers, and hopefully encourage “classical” biomedical engineers to generate new ideas and to initiate projects in an area which has traditionally been dominated by optical physics. Most of the methods involved are applicable to other areas of biomedical optics and optoelectronics, such as microscopic imaging, spectroscopy, spectral imaging, opto-acoustic tomography, fluorescence imaging etc., all of which are with potential biomedical application. Although all described methods are novel and important, the emphasis of this review has been placed on three technologies introduced in the 1990’s and still undergoing vigorous development: Confocal Scanning Laser Ophthalmoscopy, Optical Coherence Tomography, and polarization-sensitive retinal scanning. PMID:24779618

Eye-motion-corrected optical coherence tomography angiography using Lissajous scanning.

PubMed

Chen, Yiwei; Hong, Young-Joo; Makita, Shuichi; Yasuno, Yoshiaki

2018-03-01

To correct eye motion artifacts in en face optical coherence tomography angiography (OCT-A) images, a Lissajous scanning method with subsequent software-based motion correction is proposed. The standard Lissajous scanning pattern is modified to be compatible with OCT-A and a corresponding motion correction algorithm is designed. The effectiveness of our method was demonstrated by comparing en face OCT-A images with and without motion correction. The method was further validated by comparing motion-corrected images with scanning laser ophthalmoscopy images, and the repeatability of the method was evaluated using a checkerboard image. A motion-corrected en face OCT-A image from a blinking case is presented to demonstrate the ability of the method to deal with eye blinking. Results show that the method can produce accurate motion-free en face OCT-A images of the posterior segment of the eye in vivo .

Optical coherence tomography study of retinal changes in normal aging and after ischemia.

PubMed

Shariati, Mohammad Ali; Park, Joyce Ho; Liao, Yaping Joyce

2015-05-01

Age-related thinning of the retinal ganglion cell axons in the nerve fiber layer has been measured in humans using optical coherence tomography (OCT). In this study, we used OCT to measure inner retinal changes in 3-month-, 1-year-, and 2-year-old mice and after experimental anterior ischemic optic neuropathy (AION). We used OCT to quantify retinal thickness in over 200 eyes at different ages before and after a photochemical thrombosis model of AION. The scans were manually or automatically segmented. In normal aging, there was 1.3-μm thinning of the ganglion cell complex (GCC) between 3 months and 1 year (P < 0.0001) and no further thinning at 2 years. In studying age-related inner retinal changes, measurement of the GCC (circular scan) was superior to that of the total retinal thickness (posterior pole scan) despite the need for manual segmentation because it was not contaminated by outer retinal changes. Three weeks after AION, there was 8.9-μm thinning of the GCC (circular scan; P < 0.0001), 50-μm thinning of the optic disc (posterior pole scan; P < 0.0001), and 17-μm thinning of the retina (posterior pole scan; P < 0.0001) in the 3-month-old group. Changes in the older eyes after AION were similar to those of the 3-month-old group. Optical coherence tomography imaging of a large number of eyes showed that, like humans, mice exhibited small, age-related inner retinal thinning. Measurement of the GCC was superior to total retinal thickness in quantifying age-related changes, and both circular and posterior pole scans were useful to track short-term changes after AION.

Unusual Asymptomatic Fluorodeoxyglucose Avid Pheochromocytoma in a Case of Myxoid Liposarcoma of the Extremity on 18-F Fluorodeoxyglucose Positron Emission Tomography-computed Tomography.

PubMed

Shivdasani, Divya; Singh, Natasha; Pereira, Melvika; Zade, Anand

2017-01-01

Sarcomas are a heterogeneous group of rare tumors and arise either from soft tissue or from bone. Soft-tissue sarcomas (STSs) initially metastasize to the lungs. Metastases to extrapulmonary sites such as liver, brain, and soft tissue distant from primary tumor usually develop later. However, cases with isolated adrenal metastasis without disseminated disease have been reported in literature. We present a case of primary myxoid liposarcoma of the lower limb, in which staging 18 -F fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) scan detected a suspicious FDG avid adrenal lesion which eventually on resection was diagnosed as asymptomatic pheochromocytoma. Pheochromocytomas have been reported to demonstrate FDG uptake mimicking metastasis. Hence, while interpreting FDG PET-CT scans in the context of STSs, both the extrapulmonary metastatic potential of aggressive histological subtypes of sarcoma and rare possibility of FDG avid coexistent benign tumor should be taken into consideration.

Congruence Between Pulmonary Function and Computed Tomography Imaging Assessment of Cystic Fibrosis Severity.

PubMed

Rybacka, Anna; Goździk-Spychalska, Joanna; Rybacki, Adam; Piorunek, Tomasz; Batura-Gabryel, Halina; Karmelita-Katulska, Katarzyna

2018-05-04

In cystic fibrosis, pulmonary function tests (PFTs) and computed tomography are used to assess lung function and structure, respectively. Although both techniques of assessment are congruent there are lingering doubts about which PFTs variables show the best congruence with computed tomography scoring. In this study we addressed the issue by reinvestigating the association between PFTs variables and the score of changes seen in computed tomography scans in patients with cystic fibrosis with and without pulmonary exacerbation. This retrospective study comprised 40 patients in whom PFTs and computed tomography were performed no longer than 3 weeks apart. Images (inspiratory: 0.625 mm slice thickness, 0.625 mm interval; expiratory: 1.250 mm slice thickness, 10 mm interval) were evaluated with the Bhalla scoring system. The most frequent structural abnormality found in scans were bronchiectases and peribronchial thickening. The strongest relationship was found between the Bhalla sore and forced expiratory volume in 1 s (FEV1). The Bhalla sore also was related to forced vital capacity (FVC), FEV1/FVC ratio, residual volume (RV), and RV/total lung capacity (TLC) ratio. We conclude that lung structural data obtained from the computed tomography examination are highly congruent to lung function data. Thus, computed tomography imaging may supersede functional assessment in cases of poor compliance with spirometry procedures in the lederly or children. Computed tomography also seems more sensitive than PFTs in the assessment of cystic fibrosis progression. Moreover, in early phases of cystic fibrosis, computed tomography, due to its excellent resolution, may be irreplaceable in monitoring pulmonary damage.

3D analysis of semiconductor devices: A combination of 3D imaging and 3D elemental analysis

NASA Astrophysics Data System (ADS)

Fu, Bianzhu; Gribelyuk, Michael A.

2018-04-01

3D analysis of semiconductor devices using a combination of scanning transmission electron microscopy (STEM) Z-contrast tomography and energy dispersive spectroscopy (EDS) elemental tomography is presented. 3D STEM Z-contrast tomography is useful in revealing the depth information of the sample. However, it suffers from contrast problems between materials with similar atomic numbers. Examples of EDS elemental tomography are presented using an automated EDS tomography system with batch data processing, which greatly reduces the data collection and processing time. 3D EDS elemental tomography reveals more in-depth information about the defect origin in semiconductor failure analysis. The influence of detector shadowing and X-rays absorption on the EDS tomography's result is also discussed.

Doppler optical coherence tomography of retinal circulation.

PubMed

Tan, Ou; Wang, Yimin; Konduru, Ranjith K; Zhang, Xinbo; Sadda, SriniVas R; Huang, David

2012-09-18

Noncontact retinal blood flow measurements are performed with a Fourier domain optical coherence tomography (OCT) system using a circumpapillary double circular scan (CDCS) that scans around the optic nerve head at 3.40 mm and 3.75 mm diameters. The double concentric circles are performed 6 times consecutively over 2 sec. The CDCS scan is saved with Doppler shift information from which flow can be calculated. The standard clinical protocol calls for 3 CDCS scans made with the OCT beam passing through the superonasal edge of the pupil and 3 CDCS scan through the inferonal pupil. This double-angle protocol ensures that acceptable Doppler angle is obtained on each retinal branch vessel in at least 1 scan. The CDCS scan data, a 3-dimensional volumetric OCT scan of the optic disc scan, and a color photograph of the optic disc are used together to obtain retinal blood flow measurement on an eye. We have developed a blood flow measurement software called "Doppler optical coherence tomography of retinal circulation" (DOCTORC). This semi-automated software is used to measure total retinal blood flow, vessel cross section area, and average blood velocity. The flow of each vessel is calculated from the Doppler shift in the vessel cross-sectional area and the Doppler angle between the vessel and the OCT beam. Total retinal blood flow measurement is summed from the veins around the optic disc. The results obtained at our Doppler OCT reading center showed good reproducibility between graders and methods (<10%). Total retinal blood flow could be useful in the management of glaucoma, other retinal diseases, and retinal diseases. In glaucoma patients, OCT retinal blood flow measurement was highly correlated with visual field loss (R(2)>0.57 with visual field pattern deviation). Doppler OCT is a new method to perform rapid, noncontact, and repeatable measurement of total retinal blood flow using widely available Fourier-domain OCT instrumentation. This new technology may improve the practicality of making these measurements in clinical studies and routine clinical practice.

Integration of Digital Dental Casts in Cone-Beam Computed Tomography Scans

PubMed Central

Rangel, Frits A.; Maal, Thomas J. J.; Bergé, Stefaan J.; Kuijpers-Jagtman, Anne Marie

2012-01-01

Cone-beam computed tomography (CBCT) is widely used in maxillofacial surgery. The CBCT image of the dental arches, however, is of insufficient quality to use in digital planning of orthognathic surgery. Several authors have described methods to integrate digital dental casts into CBCT scans, but all reported methods have drawbacks. The aim of this feasibility study is to present a new simplified method to integrate digital dental casts into CBCT scans. In a patient scheduled for orthognathic surgery, titanium markers were glued to the gingiva. Next, a CBCT scan and dental impressions were made. During the impression-taking procedure, the titanium markers were transferred to the impression. The impressions were scanned, and all CBCT datasets were exported in DICOM format. The two datasets were matched, and the dentition derived from the scanned impressions was transferred to the CBCT of the patient. After matching the two datasets, the average distance between the corresponding markers was 0.1 mm. This novel method allows for the integration of digital dental casts into CBCT scans, overcoming problems such as unwanted extra radiation exposure, distortion of soft tissues due to the use of bite jigs, and time-consuming digital data handling. PMID:23050159

Detection of periimplant fenestration and dehiscence with the use of two scan modes and the smallest voxel sizes of a cone-beam computed tomography device.

PubMed

de-Azevedo-Vaz, Sergio Lins; Vasconcelos, Karla de Faria; Neves, Frederico Sampaio; Melo, Saulo Leonardo Sousa; Campos, Paulo Sérgio Flores; Haiter-Neto, Francisco

2013-01-01

To assess the accuracy of cone-beam computed tomography (CBCT) in periimplant fenestration and dehiscence detection, and to determine the effects of 2 voxel sizes and scan modes. One hundred titanium implants were placed in bovine ribs in which periimplant fenestration and dehiscence were simulated. CBCT images were acquired with the use of 3 protocols of the i-CAT NG unit: A) 0.2 mm voxel size half-scan (180°); B) 0.2 mm voxel size full-scan (360°); and C) 0.12 mm voxel size full scan (360°). Receiver operating characteristic curves and diagnostic values were obtained. The Az values were compared with the use of analysis of variance. The Az value for dehiscence in protocol A was significantly lower than those of B or C (P < .01). They did not statistically differ for fenestration (P > .05). Protocol B yielded the highest values. The voxel sizes did not affect fenestration and dehiscence detection, and for dehiscence full-scan performed better than half-scan. Copyright © 2013 Elsevier Inc. All rights reserved.

[A computerised clinical decision-support system for the management of depression in Primary Care].

PubMed

Aragonès, Enric; Comín, Eva; Cavero, Myriam; Pérez, Víctor; Molina, Cristina; Palao, Diego

Despite its clinical relevance and its importance as a public health problem, there are major gaps in the management of depression. Evidence-based clinical guidelines are useful to improve processes and clinical outcomes. In order to make their implementation easier these guidelines have been transformed into computerised clinical decision support systems. In this article, a description is presented on the basics and characteristics of a new computerised clinical guideline for the management of major depression, developed in the public health system in Catalonia. This tool helps the clinician to establish reliable and accurate diagnoses of depression, to choose the best treatment a priori according to the disease and the patient characteristics. It also emphasises the importance of systematic monitoring to assess the clinical course, and to adjust therapeutic interventions to the patient's needs at all times. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

The Melbourne East Monash General Practice Database (MAGNET): Using data from computerised medical records to create a platform for primary care and health services research.

PubMed

Mazza, Danielle; Pearce, Christopher; Turner, Lyle Robert; De Leon-Santiago, Maria; McLeod, Adam; Ferriggi, Jason; Shearer, Marianne

2016-07-04

The Melbourne East MonAsh GeNeral PracticE DaTabase (MAGNET) research platform was launched in 2013 to provide a unique data source for primary care and health services research in Australia.  MAGNET contains information from the computerised records of 50 participating general practices and includes data from the computerised medical records of more than 1,100,000 patients.  The data extracted is patient-level episodic information and includes a variety of fields related to patient demographics and historical clinical information, along with the characteristics of the participating general practices.  While there are limitations to the data that is currently available, the MAGNET research platform continues to investigate other avenues for improving the breadth and quality of data, with the aim of providing a more comprehensive picture of primary care in Australia.

Computerised electronic foetal heart rate monitoring in labour: automated contraction identification.

PubMed

Georgieva, A; Payne, S J; Redman, C W G

2009-12-01

The foetal heart rate (FHR) response to uterine contractions is crucial to detect foetal distress by electronic FHR monitoring during labour. We are developing a new automated system (OxSys) for decision support in labour, using the Oxford database of intrapartum FHR records. We describe here a novel technique for automated detection of uterus contractions. In addition, we present a comparison of the new method with four other computerised approaches. During training, OxSys achieved sensitivity above 95% and positive predictive value (PPV) of up to 90% for traces of good quality. During testing, OxSys achieved sensitivity = 87% and PPV = 75%. For comparison, a second clinical expert obtained sensitivity = 93% and PPV = 80%, and all other computerised approaches achieved lower values. It was concluded that the proposed method can be employed with confidence in our study on foetal health assessment in labour and future OxSys development.

Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography.

PubMed

Trépout, Sylvain; Bastin, Philippe; Marco, Sergio

2017-03-12

This report describes a protocol for preparing thick biological specimens for further observation using a scanning transmission electron microscope. It also describes an imaging method for studying the 3D structure of thick biological specimens by scanning transmission electron tomography. The sample preparation protocol is based on conventional methods in which the sample is fixed using chemical agents, treated with a heavy atom salt contrasting agent, dehydrated in a series of ethanol baths, and embedded in resin. The specific imaging conditions for observing thick samples by scanning transmission electron microscopy are then described. Sections of the sample are observed using a through-focus method involving the collection of several images at various focal planes. This enables the recovery of in-focus information at various heights throughout the sample. This particular collection pattern is performed at each tilt angle during tomography data collection. A single image is then generated, merging the in-focus information from all the different focal planes. A classic tilt-series dataset is then generated. The advantage of the method is that the tilt-series alignment and reconstruction can be performed using standard tools. The collection of through-focal images allows the reconstruction of a 3D volume that contains all of the structural details of the sample in focus.

Application of fluorodeoxyglucose positron emission tomography in the management of head and neck cancers

PubMed Central

Siddiqui, Farzan; Yao, Min

2014-01-01

The use of fluorodeoxyglucose positron emission tomography (FDG PET) scan technology in the management of head and neck cancers continues to increase. We discuss the biology of FDG uptake in malignant lesions and also discuss the physics of PET imaging. The various parameters described to quantify FDG uptake in cancers including standardized uptake value, metabolic tumor volume and total lesion glycolysis are presented. PET scans have found a significant role in the diagnosis and staging of head and neck cancers. They are also being increasingly used in radiation therapy treatment planning. Many groups have also used PET derived values to serve as prognostic indicators of outcomes including loco-regional control and overall survival. FDG PET scans are also proving very useful in assessing the efficacy of treatment and management and follow-up of head and neck cancer patients. This review article focuses on the role of FDG-PET computed tomography scans in these areas for squamous cell carcinoma of the head and neck. We present the current state of the art and speculate on the future applications of this technology including protocol development, newer imaging methods such as combined magnetic resonance and PET imaging and novel radiopharmaceuticals that can be used to further study tumor biology. PMID:24976927

Assessment of dose and risk to the body following conventional and spiral computed tomography.

PubMed

Chang, L L; Chen, F D; Chang, P S; Liu, C C; Lien, H L

1995-04-01

Computed tomography (CT) is one of the most frequently used examination procedures in diagnostic radiology and the dose given to the patients is higher than in general radiographic procedures. In this study LiF chip thermoluminescent dosimeters (TLD-100) were placed in each relative organ or tissue position, including head, chest and abdomen, in a Rando phantom. CT was performed using both conventional and spiral modes, and effective dose and effective dose equivalent were assessed for each organ or tissue scanned. The TLD reader used in this experiment was controlled at a nitrogen flow rate of 450 ml/min, preheat time of 14 seconds, reading time of 16 seconds and annealing time of 16 seconds. This CT scanner can be used to perform both conventional and spiral tomography. Operating conditions for spiral tomography were 120 kV, 80 mA for scout film, and 120 kV, 200 mA, 1 sec/slice for each scanning. However, for conventional tomography, the operating conditions were 120 kV, 80 mA for scout film and 120 kV, 160 mA, 1.5 sec/slice for each scanning. These operating conditions are satisfactory to most clinical applications, and therefore were adopted for the present studies. Results showed that, in both effective dose and effective dose and effective dose equivalent, conventional tomography was higher than spiral tomography. The average effective doses for each part were measured to be 1.89 and 4.95 mSv for the head, 30.01 and 40.65 mSv for the chest, and 12.85 and 19.62 mSv for the abdomen of spiral and conventional CT, respectively. Higher carcinogenic risk was assessed in organs such as liver, lung, stomach and bone marrow, other organs had a relatively lower incidence of risk. The main purpose of this study was to obtain distribution values of effective dose and effective dose equivalent, and to know the probability of carcinogenic effect upon each organ or tissue after CT scanning. Results showed the average effective dose for spiral CT to be less than conventional CT, and the dose in the body surface was generally lower than the dose in the central region.

Preparation of cryofixed cells for improved 3D ultrastructure with scanning transmission electron tomography.

PubMed

Höhn, Katharina; Sailer, Michaela; Wang, Li; Lorenz, Myriam; Schneider, Marion E; Walther, Paul

2011-01-01

Scanning transmission electron tomography offers enhanced contrast compared to regular transmission electron microscopy, and thicker samples, up to 1 μm or more, can be analyzed, since the depth of focus and inelastic scattering are not limitations. In this study, we combine this novel imaging approach with state of the art specimen preparation by using novel light transparent sapphire specimen carrier for high-pressure freezing and a freeze substitution protocol for better contrast of membranes. This combination allows for imaging membranes and other subcellular structures with unsurpassed quality. This is demonstrated with mitochondria, where the inner and outer mitochondrial membranes as well as the membranes in the cristae appear in very close apposition with a minimal intermembrane space. These findings correspond well with old observations using freeze fracturing. In 880-nm thick sections of hemophagocytes, the three-dimensional structure of membrane sheets could be observed in the virtual sections of the tomogram. Microtubules, actin and intermediate filaments could be visualized within one sample. Intermediate filaments, however, could even be better observed in 3D using surface scanning electron tomography.

4D computed tomography scans for conformal thoracic treatment planning: is a single scan sufficient to capture thoracic tumor motion?

NASA Astrophysics Data System (ADS)

Tseng, Yolanda D.; Wootton, Landon; Nyflot, Matthew; Apisarnthanarax, Smith; Rengan, Ramesh; Bloch, Charles; Sandison, George; St. James, Sara

2018-01-01

Four dimensional computed tomography (4DCT) scans are routinely used in radiation therapy to determine the internal treatment volume for targets that are moving (e.g. lung tumors). The use of these studies has allowed clinicians to create target volumes based upon the motion of the tumor during the imaging study. The purpose of this work is to determine if a target volume based on a single 4DCT scan at simulation is sufficient to capture thoracic motion. Phantom studies were performed to determine expected differences between volumes contoured on 4DCT scans and those on the evaluation CT scans (slow scans). Evaluation CT scans acquired during treatment of 11 patients were compared to the 4DCT scans used for treatment planning. The images were assessed to determine if the target remained within the target volume determined during the first 4DCT scan. A total of 55 slow scans were compared to the 11 planning 4DCT scans. Small differences were observed in phantom between the 4DCT volumes and the slow scan volumes, with a maximum of 2.9%, that can be attributed to minor differences in contouring and the ability of the 4DCT scan to adequately capture motion at the apex and base of the motion trajectory. Larger differences were observed in the patients studied, up to a maximum volume difference of 33.4%. These results demonstrate that a single 4DCT scan is not adequate to capture all thoracic motion throughout treatment.

MOEMS optical delay line for optical coherence tomography

NASA Astrophysics Data System (ADS)

Choudhary, Om P.; Chouksey, S.; Sen, P. K.; Sen, P.; Solanki, J.; Andrews, J. T.

2014-09-01

Micro-Opto-Electro-Mechanical optical coherence tomography, a lab-on-chip for biomedical applications is designed, studied, fabricated and characterized. To fabricate the device standard PolyMUMPS processes is adopted. We report the utilization of electro-optic modulator for a fast scanning optical delay line for time domain optical coherence tomography. Design optimization are performed using Tanner EDA while simulations are performed using COMSOL. The paper summarizes various results and fabrication methodology adopted. The success of the device promises a future hand-held or endoscopic optical coherence tomography for biomedical applications.

Three-dimensional multifunctional optical coherence tomography for skin imaging

NASA Astrophysics Data System (ADS)

Li, En; Makita, Shuichi; Hong, Young-Joo; Kasaragod, Deepa; Sasaoka, Tomoko; Yamanari, Masahiro; Sugiyama, Satoshi; Yasuno, Yoshiaki

2016-02-01

Optical coherence tomography (OCT) visualizes cross-sectional microstructures of biological tissues. Recent developments of multifunctional OCT (MF-OCT) provides multiple optical contrasts which can reveal currently unknown tissue properties. In this contribution we demonstrate multifunctional OCT specially designed for dermatological investigation. And by utilizing it to measure four different body parts of in vivo human skin, three-dimensional scattering OCT, OCT angiography, polarization uniformity tomography, and local birefringence tomography images were obtained by a single scan. They respectively contrast the structure and morphology, vasculature, melanin content and collagen traits of the tissue.

A Comparison of Several Artificial Neural Network Classifiers for CT Images of Hardwood Logs

Treesearch

Daniel L. Schmoldt; Jing He; A. Lynn Abbott

1998-01-01

Knowledge of internal log defects, obtained by scanning, is critical to efficiency improvements for future hardwood sawmills. Nevertheless, before computed tomography (CT) scanning can be applied in industrial operations, we need to automatically interpret scan information so that it can provide the saw operator with the information necessary to make proper sawing...

Examination of Below-Ground Structure and Soil Respiration Rates of Stable and Deteriorating Salt Marshes in Jamaica Bay (NY)

EPA Science Inventory

CAT scan imaging is currently being used to examine below-ground peat and root structure in cores collected from salt marshes of Jamaica Bay, part of the Gateway National Recreation Area (NY). CAT scans or Computer-Aided Tomography scans use X-ray equipment to produce multiple i...

Model PET Scan Activity

NASA Astrophysics Data System (ADS)

Strunk, Amber; Gazdovich, Jennifer; Redouté, Oriane; Reverte, Juan Manuel; Shelley, Samantha; Todorova, Vesela

2018-05-01

This paper provides a brief introduction to antimatter and how it, along with other modern physics topics, is utilized in positron emission tomography (PET) scans. It further describes a hands-on activity for students to help them gain an understanding of how PET scans assist in detecting cancer. Modern physics topics provide an exciting way to introduce students to current applications of physics.

Occupancy of Norepinephrine Transporter by Duloxetine in Human Brains Measured by Positron Emission Tomography with (S,S)-[18F]FMeNER-D2.

PubMed

Moriguchi, Sho; Takano, Harumasa; Kimura, Yasuyuki; Nagashima, Tomohisa; Takahata, Keisuke; Kubota, Manabu; Kitamura, Soichiro; Ishii, Tatsuya; Ichise, Masanori; Zhang, Ming-Rong; Shimada, Hitoshi; Mimura, Masaru; Meyer, Jeffrey H; Higuchi, Makoto; Suhara, Tetsuya

2017-12-01

The norepinephrine transporter in the brain has been targeted in the treatment of psychiatric disorders. Duloxetine is a serotonin and norepinephrine reuptake inhibitor that has been widely used for the treatment of depression. However, the relationship between dose and plasma concentration of duloxetine and norepinephrine transporter occupancy in the human brain has not been determined. In this study, we examined norepinephrine transporter occupancy by different doses of duloxetine. We calculated norepinephrine transporter occupancies from 2 positron emission tomography scans using (S,S)-[18F]FMeNER-D2 before and after a single oral dose of duloxetine (20 mg, n = 3; 40 mg, n = 3; 60 mg, n =2). Positron emission tomography scans were performed from 120 to 180 minutes after an i.v. bolus injection of (S,S)-[18F]FMeNER-D2. Venous blood samples were taken to measure the plasma concentration of duloxetine just before and after the second positron emission tomography scan. Norepinephrine transporter occupancy by duloxetine was 29.7% at 20 mg, 30.5% at 40 mg, and 40.0% at 60 mg. The estimated dose of duloxetine inducing 50% norepinephrine transporter occupancy was 76.8 mg, and the estimated plasma drug concentration inducing 50% norepinephrine transporter occupancy was 58.0 ng/mL. Norepinephrine transporter occupancy by clinical doses of duloxetine was approximately 30% to 40% in human brain as estimated using positron emission tomography with (S,S)-[18F]FMeNER-D2. © The Author 2017. Published by Oxford University Press on behalf of CINP.

Diagnostic accuracy of oblique chest radiograph for occult pneumothorax: comparison with ultrasonography.

PubMed

Matsumoto, Shokei; Sekine, Kazuhiko; Funabiki, Tomohiro; Orita, Tomohiko; Shimizu, Masayuki; Hayashida, Kei; Kazamaki, Taku; Suzuki, Tatsuya; Kishikawa, Masanobu; Yamazaki, Motoyasu; Kitano, Mitsuhide

2016-01-01

An occult pneumothorax is a pneumothorax that is not seen on a supine chest X-ray but is detected by computed tomography scanning. However, critical patients are difficult to transport to the computed tomography suite. We previously reported a method to detect occult pneumothorax using oblique chest radiography (OXR). Several authors have also reported that ultrasonography is an effective technique for detecting occult pneumothorax. The aim of this study was to evaluate the usefulness of OXR in the diagnosis of the occult pneumothorax and to compare OXR with ultrasonography. All consecutive blunt chest trauma patients with clinically suspected pneumothorax on arrival at the emergency department were prospectively included at our tertiary-care center. The patients underwent OXR and ultrasonography, and underwent computed tomography scans as the gold standard. Occult pneumothorax size on computed tomography was classified as minuscule, anterior, or anterolateral. One hundred and fifty-nine patients were enrolled. Of the 70 occult pneumothoraces found in the 318 thoraces, 19 were minuscule, 32 were anterior, and 19 were anterolateral. The sensitivity and specificity of OXR for detecting occult pneumothorax was 61.4 % and 99.2 %, respectively. The sensitivity and specificity of lung ultrasonography was 62.9 % and 98.8 %, respectively. Among 27 occult pneumothoraces that could not be detected by OXR, 16 were minuscule and 21 could be conservatively managed without thoracostomy. OXR appears to be as good method as lung ultrasonography in the detection of large occult pneumothorax. In trauma patients who are difficult to transfer to computed tomography scan, OXR may be effective at detecting occult pneumothorax with a risk of progression.

Integrated scanning laser ophthalmoscopy and optical coherence tomography for quantitative multimodal imaging of retinal degeneration and autofluorescence

NASA Astrophysics Data System (ADS)

Issaei, Ali; Szczygiel, Lukasz; Hossein-Javaheri, Nima; Young, Mei; Molday, L. L.; Molday, R. S.; Sarunic, M. V.

2011-03-01

Scanning Laser Ophthalmoscopy (SLO) and Coherence Tomography (OCT) are complimentary retinal imaging modalities. Integration of SLO and OCT allows for both fluorescent detection and depth- resolved structural imaging of the retinal cell layers to be performed in-vivo. System customization is required to image rodents used in medical research by vision scientists. We are investigating multimodal SLO/OCT imaging of a rodent model of Stargardt's Macular Dystrophy which is characterized by retinal degeneration and accumulation of toxic autofluorescent lipofuscin deposits. Our new findings demonstrate the ability to track fundus autofluorescence and retinal degeneration concurrently.

Comparison of computed tomography and complex motion tomography in the evaluation of cholesteatoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaffer, K.A.

1984-08-01

High-resolution axial and coronal computed tomographic (CT) scans were compared with coronal and sagittal complex motion tomograms in patients with suspected middle ear cholesteatomas. Information on CT scans equaled or exceeded that on conventional complex motion tomograms in 16 of 17 patients, and in 11 it provided additional information. Soft-tissue resolution was superior with CT. In 14 patients who underwent surgery, CT provided information that was valuable to the surgeon. On the basis of this study, high-resolution CT is recommended as the preferred method for evaluating most patients with cholesteatomas of the temporal bone.

Optimization in modeling the ribs-bounded contour from computer tomography scan

NASA Astrophysics Data System (ADS)

Bilinskas, M. J.; Dzemyda, G.

2016-10-01

In this paper a method for analyzing transversal plane images from computer tomography scans is presented. A mathematical model that describes the ribs-bounded contour was created and the problem of approximation is solved by finding out the optimal parameters of the model in the least-squares sense. Such model would be useful in registration of images independently on the patient position on the bed and on the radio-contrast agent injection. We consider the slices, where ribs are visible, because many important internal organs are located here: liver, heart, stomach, pancreas, lung, etc.

Fiber optic-based optical coherence tomography (OCT) for dental applications

NASA Astrophysics Data System (ADS)

Everett, Matthew J.; Colston, Bill W., Jr.; Da Silva, Luiz B.; Otis, Linda L.

1998-09-01

We have developed a hand-held fiber optic based optical coherence tomography (OCT) system for scanning of the oral cavity. We have produced, using this scanning device, in vivo cross-sectional images of hard and soft dental tissues in human volunteers. Clinically relevant anatomical structures, including the gingival margin, periodontal sulcus, and dento- enamel junction, were visible in all the images. The cemento- enamel junction and the alveolar bone were identified in approximately two thirds of the images. These images represent, or our knowledge, the first in vivo OCT images of human dental tissue.

Use of multidetector-row computed tomography scan to detect pannus formation in prosthetic mechanical aortic valves.

PubMed

Aladmawi, Mohamed A; Pragliola, Claudio; Vriz, Olga; Galzerano, Domenico

2017-04-01

Obstruction of a mechanical aortic valve by pannus formation at the subvalvular level is a major long-term complication of aortic valve replacement (AVR). In fact, pannus is sometime difficult to differentiate from patient-prosthesis mismatch or valve thrombosis. In most cases cine-angiography and echocardiography, either transthoracic or transesophageal, cannot correctly visualize the complication when the leaflets show a normal mobility. Recent technological refinements made this difficult diagnosis possible by ECG-gated computed tomography (CT) scan which shows adequate images in 90% of the cases and can differentiate pannus from fresh and organized thrombus.

(Full field) optical coherence tomography and applications

NASA Astrophysics Data System (ADS)

Buchroithner, Boris; Hannesschläger, Günther; Leiss-Holzinger, Elisabeth; Prylepa, Andrii; Heise, Bettina

2018-03-01

This paper illustrates specific features and use of optical coherence tomography (OCT) in the raster-scanning and in comparison in the full field version of this imaging technique. Cases for nondestructive testing are discussed alongside other application schemes. In particular monitoring time-dependent processes and probing of birefringent specimens are considered here. In the context of polymer testing birefringence mapping may often provide information about internal strain and stress states. Recent results obtained with conventional raster-scanning OCT systems, with (dual and single-shot) full field OCT configurations, and with polarization-sensitive versions of (full field) OCT are presented here.

Ward nurses' knowledge of computed tomography scanning.

PubMed

Majeed, M A; Nayeemuddin, M; Christie, M

Patients benefit from and are reassured by advance information on procedures that they are to undergo. Ward nurses should have adequate knowledge of radiological investigations to ensure proper patient preparation and good interdepartmental communication to avoid delays and cancellations. This study was conducted to assess the ward nurses' knowledge of the process of computed tomography (CT) scanning. One hundred and twenty qualified nurses were asked to complete a questionnaire regarding CT scanning. The findings revealed a suboptimal level of awareness about the process. This is probably due to lack of formal teaching for nurses on the wards in regards the different radiological procedures and patient preparation. There is a strong case for better educational talks on rapidly changing radiological techniques for ward staff to ensure high-quality patient care.

Enhanced visualization of acute macular neuroretinopathy by Heidelberg Retina Tomography.

PubMed

Mirshahi, Alireza; Scharioth, Gàbor B; Klais, Christina M C; Baatz, Holger

2006-08-01

We report Heidelberg Retina Tomography (HRT) findings in a case of bilateral acute macular neuroretinopathy in a 22-year-old man. In addition to fundus photography, fluorescein and indocyanine green angiography, and visual field testing, HRT scans of the macula were performed early in the disease and at a follow up of 2 months. We found typical paracentral scotomata in visual field testing corresponding to sharply delineated, hyporeflective areas of the macula as visualized in HRT II scans. Those lesions were almost invisible on regular fundus photographs. Angiography results were unremarkable. The lesion size decreased over time. The visibility of the lesions was markedly enhanced by HRT scans, thus the diagnosis and follow up of acute macular neuroretinopathy could be facilitated by this non-invasive imaging technique.

Estimation of bias and variance of measurements made from tomography scans

NASA Astrophysics Data System (ADS)

Bradley, Robert S.

2016-09-01

Tomographic imaging modalities are being increasingly used to quantify internal characteristics of objects for a wide range of applications, from medical imaging to materials science research. However, such measurements are typically presented without an assessment being made of their associated variance or confidence interval. In particular, noise in raw scan data places a fundamental lower limit on the variance and bias of measurements made on the reconstructed 3D volumes. In this paper, the simulation-extrapolation technique, which was originally developed for statistical regression, is adapted to estimate the bias and variance for measurements made from a single scan. The application to x-ray tomography is considered in detail and it is demonstrated that the technique can also allow the robustness of automatic segmentation strategies to be compared.

High-pressure freezing for scanning transmission electron tomography analysis of cellular organelles.

PubMed

Walther, Paul; Schmid, Eberhard; Höhn, Katharina

2013-01-01

Using an electron microscope's scanning transmission mode (STEM) for collection of tomographic datasets is advantageous compared to bright field transmission electron microscopic (TEM). For image formation, inelastic scattering does not cause chromatic aberration, since in STEM mode no image forming lenses are used after the beam has passed the sample, in contrast to regular TEM. Therefore, thicker samples can be imaged. It has been experimentally demonstrated that STEM is superior to TEM and energy filtered TEM for tomography of samples as thick as 1 μm. Even when using the best electron microscope, adequate sample preparation is the key for interpretable results. We adapted protocols for high-pressure freezing of cultivated cells from a physiological state. In this chapter, we describe optimized high-pressure freezing and freeze substitution protocols for STEM tomography in order to obtain high membrane contrast.

Rapid in vivo vertical tissue sectioning by multiphoton tomography

NASA Astrophysics Data System (ADS)

Batista, Ana; Breunig, Hans Georg; König, Karsten

2018-02-01

A conventional tool in the pathological field is histology which involves the analysis of thin sections of tissue in which specific cellular structures are stained with different dyes. The process to obtain these stained tissue sections is time consuming and invasive as it requires tissue removal, fixation, sectioning, and staining. Moreover, imaging of live tissue is not possible. We demonstrate that multiphoton tomography can provide within seconds, non-invasive, label-free, vertical images of live tissue which are in quality similar to conventional light micrographs of histologic stained specimen. In contrast to conventional setups based on laser scanning which image horizontally sections, the vertical in vivo images are directly recorded by combined line scanning and timed adjustments of the height of the focusing optics. In addition, multiphoton tomography provides autofluorescence lifetimes which can be used to determine the metabolic states of cells.

Impact of Scanning Density on Measurements from Spectral Domain Optical Coherence Tomography

PubMed Central

Keane, Pearse A.; Ouyang, Yanling; Updike, Jared F.; Walsh, Alexander C.

2010-01-01

Purpose. To investigate the relationship between B-scan density and retinal thickness measurements obtained by spectral domain optical coherence tomography (SDOCT) in eyes with retinal disease. Methods. Data were collected from 115 patients who underwent volume OCT imaging with Cirrus HD-OCT using the 512 × 128 horizontal raster protocol. Raw OCT data, including the location of the automated retinal boundaries, were exported from the Cirrus HD-OCT instrument and imported into the Doheny Image Reading Center (DIRC) OCT viewing and grading software, termed “3D-OCTOR.” For each case, retinal thickness maps similar to those produced by Cirrus HD-OCT were generated using all 128 B-scans, as well as using less dense subsets of scans, ranging from every other scan to every 16th scan. Retinal thickness measurements derived using only a subset of scans were compared to measurements using all 128 B-scans, and differences for the foveal central subfield (FCS) and total macular volume were computed. Results. The mean error in FCS retinal thickness measurement increased as the density of B-scans decreased, but the error was small (<2 μm), except at the sparsest densities evaluated. The maximum error at a density of every fourth scan (32 scans spaced 188 μm apart) was <1%. Conclusions. B-scan density in volume SDOCT acquisitions can be reduced to 32 horizontal B-scans (spaced 188 μm apart) with minimal change in calculated retinal thickness measurements. This information may be of value in design of scanning protocols for SDOCT for use in future clinical trials. PMID:19797199

Initial clinical experience with computerized tomography of the body.

PubMed

Stephens, D H; Sheedy, P F; Hattery, R R; Hartman, G W

1976-04-01

Computerized tomography of the body, now possible with an instrument that can complete a scan rapidly enough to permit patients to suspend respiration, adds an important new dimension to radiologic diagnosis. Cross-sectional antomy is uniquely reconstructed to provide accurate diagnostic information for various disorders throughout the body.

Field demonstration of magnetic tomography technology for determination of dowel bar position in concrete pavement.

DOT National Transportation Integrated Search

2006-01-01

The purpose of this study was to demonstrate and evaluate the use of magnetic tomography technology through the use of Magnetic Imaging Tools' (MIT) MIT Scan-2. The main objective was to measure the alignment of dowel bars in a few jointed plain conc...

Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography.

PubMed

Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

2016-03-01

Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations.

The potential of positron emission tomography/computerized tomography (PET/CT) scanning as a detector of high-risk patients with oral infection during preoperative staging.

PubMed

Yamashiro, Keisuke; Nakano, Makoto; Sawaki, Koichi; Okazaki, Fumihiko; Hirata, Yasuhisa; Takashiba, Shogo

2016-08-01

It is sometimes difficult to determine during the preoperative period whether patients have oral infections; these patients need treatment to prevent oral infection-related complications from arising during medical therapies, such as cancer therapy and surgery. One of the reasons for this difficulty is that basic medical tests do not identify oral infections, including periodontitis and periapical periodontitis. In this report, we investigated the potential of positron emission tomography/computerized tomography (PET/CT) as a diagnostic tool in these patients. We evaluated eight patients during the preoperative period. All patients underwent PET/CT scanning and were identified as having the signs of oral infection, as evidenced by (18)F-fludeoxyglucose (FDG) localization in the oral regions. Periodontal examination and orthopantomogram evaluation showed severe infection or bone resorption in the oral regions. (18)F-FDG was localized in oral lesions, such as severe periodontitis, apical periodontitis, and pericoronitis of the third molar. The densities of (18)F-FDG were proportional to the degree of inflammation. PET/CT is a potential diagnostic tool for oral infections. It may be particularly useful in patients during preoperative staging, as they frequently undergo scanning at this time, and those identified as having oral infections at this time require treatment before cancer therapy or surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images.

PubMed

Kim, Jooseong; Lagravére, Manuel O

2016-01-01

The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

Can computerized tomography accurately stage childhood renal tumors?

PubMed

Abdelhalim, Ahmed; Helmy, Tamer E; Harraz, Ahmed M; Abou-El-Ghar, Mohamed E; Dawaba, Mohamed E; Hafez, Ashraf T

2014-07-01

Staging of childhood renal tumors is crucial for treatment planning and outcome prediction. We sought to identify whether computerized tomography could accurately predict the local stage of childhood renal tumors. We retrospectively reviewed our database for patients diagnosed with childhood renal tumors and treated surgically between 1990 and 2013. Inability to retrieve preoperative computerized tomography, intraoperative tumor spillage and nonWilms childhood renal tumors were exclusion criteria. Local computerized tomography stage was assigned by a single experienced pediatric radiologist blinded to the pathological stage, using a consensus similar to the Children's Oncology Group Wilms tumor staging system. Tumors were stratified into up-front surgery and preoperative chemotherapy groups. The radiological stage of each tumor was compared to the pathological stage. A total of 189 tumors in 179 patients met inclusion criteria. Computerized tomography staging matched pathological staging in 68% of up-front surgery (70 of 103), 31.8% of pre-chemotherapy (21 of 66) and 48.8% of post-chemotherapy scans (42 of 86). Computerized tomography over staged 21.4%, 65.2% and 46.5% of tumors in the up-front surgery, pre-chemotherapy and post-chemotherapy scans, respectively, and under staged 10.7%, 3% and 4.7%. Computerized tomography staging was more accurate in tumors managed by up-front surgery (p <0.001) and those without extracapsular extension (p <0.001). The validity of computerized tomography staging of childhood renal tumors remains doubtful. This staging is more accurate for tumors treated with up-front surgery and those without extracapsular extension. Preoperative computerized tomography can help to exclude capsular breach. Treatment strategy should be based on surgical and pathological staging to avoid the hazards of inaccurate staging. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Understanding the acceptability of e-mental health--attitudes and expectations towards computerised self-help treatments for mental health problems.

PubMed

Musiat, Peter; Goldstone, Philip; Tarrier, Nicholas

2014-04-11

E-mental health and m-mental health include the use of technology in the prevention, treatment and aftercare of mental health problems. With the economical pressure on mental health services increasing, e-mental health and m-mental health could bridge treatment gaps, reduce waiting times for patients and deliver interventions at lower costs. However, despite the existence of numerous effective interventions, the transition of computerised interventions into care is slow. The aim of the present study was to investigate the acceptability of e-mental health and m-mental health in the general population. An advisory group of service users identified dimensions that potentially influence an individual's decision to engage with a particular treatment for mental health problems. A large sample (N = 490) recruited through email, flyers and social media was asked to rate the acceptability of different treatment options for mental health problems on these domains. Results were analysed using repeated measures MANOVA. Participants rated the perceived helpfulness of an intervention, the ability to motivate users, intervention credibility, and immediate access without waiting time as most important dimensions with regard to engaging with a treatment for mental health problems. Participants expected face-to-face therapy to meet their needs on most of these dimensions. Computerised treatments and smartphone applications for mental health were reported to not meet participants' expectations on most domains. However, these interventions scored higher than face-to-face treatments on domains associated with the convenience of access. Overall, participants reported a very low likelihood of using computerised treatments for mental health in the future. Individuals in this study expressed negative views about computerised self-help intervention and low likelihood of use in the future. To improve the implementation and uptake, policy makers need to improve the public perception of such interventions.

Understanding the acceptability of e-mental health - attitudes and expectations towards computerised self-help treatments for mental health problems

PubMed Central

2014-01-01

Background E-mental health and m-mental health include the use of technology in the prevention, treatment and aftercare of mental health problems. With the economical pressure on mental health services increasing, e-mental health and m-mental health could bridge treatment gaps, reduce waiting times for patients and deliver interventions at lower costs. However, despite the existence of numerous effective interventions, the transition of computerised interventions into care is slow. The aim of the present study was to investigate the acceptability of e-mental health and m-mental health in the general population. Methods An advisory group of service users identified dimensions that potentially influence an individual’s decision to engage with a particular treatment for mental health problems. A large sample (N = 490) recruited through email, flyers and social media was asked to rate the acceptability of different treatment options for mental health problems on these domains. Results were analysed using repeated measures MANOVA. Results Participants rated the perceived helpfulness of an intervention, the ability to motivate users, intervention credibility, and immediate access without waiting time as most important dimensions with regard to engaging with a treatment for mental health problems. Participants expected face-to-face therapy to meet their needs on most of these dimensions. Computerised treatments and smartphone applications for mental health were reported to not meet participants’ expectations on most domains. However, these interventions scored higher than face-to-face treatments on domains associated with the convenience of access. Overall, participants reported a very low likelihood of using computerised treatments for mental health in the future. Conclusions Individuals in this study expressed negative views about computerised self-help intervention and low likelihood of use in the future. To improve the implementation and uptake, policy makers need to improve the public perception of such interventions. PMID:24725765

CT Scans - Multiple Languages

MedlinePlus

... Tomography) Scan - العربية (Arabic) Bilingual PDF Health Information Translations Chinese, Simplified (Mandarin dialect) (简体中文) Expand Section CT ( ... Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health Information Translations Chinese, Traditional (Cantonese dialect) (繁體中文) Expand Section CT ( ...

Stages of Adult Soft Tissue Sarcoma

MedlinePlus

... that uses a magnet, radio waves , and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI). PET scan (positron emission tomography scan) : A procedure to find malignant tumor cells ...

Treatment Option Overview (Adult Soft Tissue Sarcoma)

MedlinePlus

... that uses a magnet, radio waves , and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI). PET scan (positron emission tomography scan) : A procedure to find malignant tumor cells ...

Treatment Options for Adult Soft Tissue Sarcoma

MedlinePlus

... that uses a magnet, radio waves , and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI). PET scan (positron emission tomography scan) : A procedure to find malignant tumor cells ...

Imaging Cellular Proliferation During Chemo-Radiotherapy: A Pilot Study of Serial {sup 18}F-FLT Positron Emission Tomography/Computed Tomography Imaging for Non-Small-Cell Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Everitt, Sarah, E-mail: Sarah.Everitt@petermac.or; Department of Medical Imaging and Radiation Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria; Hicks, Rodney J.

2009-11-15

Purpose: To establish whether {sup 18}F-3'-deoxy-3'-fluoro-L-thymidine ({sup 18}F-FLT) can monitor changes in cellular proliferation of non-small-cell lung cancer (NSCLC) during radical chemo-radiotherapy (chemo-RT). Methods and Materials: As part of a prospective pilot study, 5 patients with locally advanced NSCLC underwent serial {sup 18}F-FLT positron emission tomography (PET)/computed tomography (CT) scans during treatment. Baseline {sup 18}F-FLT PET/CT scans were compared with routine staging {sup 18}F-FDG PET/CT scans. Two on-treatment {sup 18}F-FLT scans were performed for each patient on Days 2, 8, 15 or 29, providing a range of time points for response assessment. Results: In all 5 patients, baseline lesional uptakemore » of {sup 18}F-FLT on PET/CT corresponded to staging {sup 18}F-FDG PET/CT abnormalities. {sup 18}F-FLT uptake in tumor was observed on five of nine (55%) on-treatment scans, on Days 2, 8 and 29, but not Day 15. A 'flare' of {sup 18}F-FLT uptake in the primary tumor of one case was observed after 2 Gy of radiation (1.22 x baseline). The remaining eight on-treatment scans demonstrated a mean reduction in {sup 18}F-FLT tumor uptake of 0.58 x baseline. A marked reduction of {sup 18}F-FLT uptake in irradiated bone marrow was observed for all cases. This reduction was observed even after only 2 Gy, and all patients demonstrated a complete absence of proliferating marrow after 10 Gy. Conclusions: This proof of concept study indicates that {sup 18}F-FLT uptake can monitor the distinctive biologic responses of epithelial cancers and highly radiosensitive normal tissue changes during radical chemo-RT. Further studies of {sup 18}F-FLT PET/CT imaging during therapy may suggest that this tracer is useful in developing response-adapted RT for NSCLC.« less

Residual FDG-PET metabolic activity in metastatic melanoma patients with prolonged response to anti-PD-1 therapy.

PubMed

Kong, Benjamin Y; Menzies, Alexander M; Saunders, Catherine A B; Liniker, Elizabeth; Ramanujam, Sangeetha; Guminski, Alex; Kefford, Richard F; Long, Georgina V; Carlino, Matteo S

2016-09-01

18-Fluorodeoxyglucose positron emission tomography (FDG-PET) scans were performed on 27 patients with unresectable stage IIIC or IV melanoma after prolonged treatment with anti-PD-1 antibodies to examine the hypothesis that patients with prolonged response to treatment may have metabolically inactive lesions by FDG-PET. Scans were performed at a median of 15.2 months (range 12-29 months) after starting treatment. Overall, 15 of 27 (56%) patients had a positive FDG-PET scan. Eight patients with positive scans underwent biopsy; 5 of 8 (62%) were melanoma and 3 of 8 (38%) were immune cell infiltrates. Of the 12 patients with negative FDG-PET scans, six had residual computerized tomography-visible lesions, five have ceased treatment, and none have recurred with follow-up of 6-10 months. Patients with residual metastases after a prolonged period without progression on anti-PD-1 therapy may have metabolically inactive lesions. Isolated metabolically active lesions in clinically well patients may reveal immune cell infiltrates rather than melanoma. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Imaging of human finger nail-fold with MHz A-scan rate swept source optical coherence tomography

NASA Astrophysics Data System (ADS)

Poddar, Raju; Mondal, Indranil

2018-07-01

We present a non-invasive three-dimensional depth-resolved micro-structure and micro-vasculature imaging of a human fingernail-fold with a swept-source optical coherence tomography (ssOCT) system at a 1064 nm center wavelength. A phase variance OCT angiography (OCTA) method was implemented for motion contrast OCT imaging. A Fourier-domain mode-locked light source with an A-scan rate of 1.7 MHz (1 700 000 A-scans s‑1) was utilized for imaging. The experimental setup demonstrates OCT and OCTA imaging with an area of ~5 mm  ×  5 mm (within the Nyquist limit). Details of the ssOCTA system such as system parameters, scanning protocols, acquisition time, challenges, and scanning density are discussed. The selected features of the nail-fold structure and vascular networks are also deliberated. The system has potential for real-time monitoring of transdermal drug delivery, and the management and diagnosis of various diseases such as connective tissue diseases and Raynaud’s phenomenon.

[Three-dimensional tooth model reconstruction based on fusion of dental computed tomography images and laser-scanned images].

PubMed

Zhang, Dongxia; Gan, Yangzhou; Xiong, Jing; Xia, Zeyang

2017-02-01

Complete three-dimensional(3D) tooth model provides essential information to assist orthodontists for diagnosis and treatment planning. Currently, 3D tooth model is mainly obtained by segmentation and reconstruction from dental computed tomography(CT) images. However, the accuracy of 3D tooth model reconstructed from dental CT images is low and not applicable for invisalign design. And another serious problem also occurs, i.e. frequentative dental CT scan during different intervals of orthodontic treatment often leads to radiation to the patients. Hence, this paper proposed a method to reconstruct tooth model based on fusion of dental CT images and laser-scanned images. A complete3 D tooth model was reconstructed with the registration and fusion between the root reconstructed from dental CT images and the crown reconstructed from laser-scanned images. The crown of the complete 3D tooth model reconstructed with the proposed method has higher accuracy. Moreover, in order to reconstruct complete 3D tooth model of each orthodontic treatment interval, only one pre-treatment CT scan is needed and in the orthodontic treatment process only the laser-scan is required. Therefore, radiation to the patients can be reduced significantly.

Serial computed tomography scanning in acute pancreatitis: a prospective study.

PubMed Central

London, N J; Neoptolemos, J P; Lavelle, J; Bailey, I; James, D

1989-01-01

One hundred and two patients with acute pancreatitis had abdominal computed tomography (CT) scans within 72 hours of admission, at one week and at six weeks. Twenty eight attacks were clinically severe, 74 clinically mild. Ninety three (91%) admission scans, 85 (84%) one week scans, and 52 (51%) six week scans were abnormal. The aetiology of the pancreatitis could be inferred from 28 (27%) of admission scans, the CT sign of fatty liver having a sensitivity of 21% and specificity of 100% for alcoholic aetiology. The sensitivity of CT for gall stone aetiology was 34%, specificity 100%. The pancreatic size indices (max anteroposterior measurement of head x max anteroposterior measurement of body) of those patients with severe attacks were significantly greater than those with mild attacks on admission, at one week and at six weeks (p less than 0.004). Fourteen pseudocysts were detected by CT, five (36%) of which were clinically apparent. The pseudocyst size indices (max anteroposterior x max transverse measurement) of the pseudocysts which were clinically apparent were significantly greater than those which were not apparent (p less than 0.01) and only those pseudocysts with a size index greater than or equal to 15 cm2 required treatment. PMID:2651228

Multimodal ophthalmic imaging using handheld spectrally encoded coherence tomography and reflectometry (SECTR)

NASA Astrophysics Data System (ADS)

Leeburg, Kelsey C.; El-Haddad, Mohamed T.; Malone, Joseph D.; Terrones, Benjamin D.; Tao, Yuankai K.

2018-02-01

Scanning laser ophthalmoscopy (SLO) provides high-speed, noninvasive en face imaging of the retinal fundus. Optical coherence tomography (OCT) is the current "gold-standard" for ophthalmic diagnostic imaging and enables depth-resolved visualization of ophthalmic structures and image-based surrogate biomarkers of disease. We present a compact optical and mechanical design for handheld spectrally encoded coherence tomography and reflectometry (SECTR) for multimodality en face spectrally encoded reflectometry (SER) and cross-sectional OCT imaging. We custom-designed a double-pass telecentric scan lens, which halves the size of 4-f optical relays and allowed us to reduce the footprint of our SECTR scan-head by a factor of >2.7x (volume) over our previous design. The double-pass scan lens was optimized for diffraction-limited performance over a +/-10° scan field. SECTR optics and optomechanics were combined in a compact rapid-prototyped enclosure with dimensions 87 x 141.8 x 137 mm (w x h x d). SECTR was implemented using a custom-built 400 kHz 1050 nm swept-source. OCT and SER were simultaneously digitized on dual input channels of a 4 GS/s digitizer at 1.4 GS/s per channel. In vivo human en face SER and cross-sectional OCT images were acquired at 350 fps. OCT volumes of 1000 B-scans were acquired in 2.86 s. We believe clinical translation of our compact handheld design will benefit point-of-care ophthalmic diagnostics in patients who are unable to be imaged on conventional slit-lamp based systems, such as infants and the bedridden. When combined with multi-volumetric registration methods, handheld SECTR will have advantages in motion-artifact free imaging over existing handheld technologies.

Precision of quantitative computed tomography texture analysis using image filtering: A phantom study for scanner variability.

PubMed

Yasaka, Koichiro; Akai, Hiroyuki; Mackin, Dennis; Court, Laurence; Moros, Eduardo; Ohtomo, Kuni; Kiryu, Shigeru

2017-05-01

Quantitative computed tomography (CT) texture analyses for images with and without filtration are gaining attention to capture the heterogeneity of tumors. The aim of this study was to investigate how quantitative texture parameters using image filtering vary among different computed tomography (CT) scanners using a phantom developed for radiomics studies.A phantom, consisting of 10 different cartridges with various textures, was scanned under 6 different scanning protocols using four CT scanners from four different vendors. CT texture analyses were performed for both unfiltered images and filtered images (using a Laplacian of Gaussian spatial band-pass filter) featuring fine, medium, and coarse textures. Forty-five regions of interest were placed for each cartridge (x) in a specific scan image set (y), and the average of the texture values (T(x,y)) was calculated. The interquartile range (IQR) of T(x,y) among the 6 scans was calculated for a specific cartridge (IQR(x)), while the IQR of T(x,y) among the 10 cartridges was calculated for a specific scan (IQR(y)), and the median IQR(y) was then calculated for the 6 scans (as the control IQR, IQRc). The median of their quotient (IQR(x)/IQRc) among the 10 cartridges was defined as the variability index (VI).The VI was relatively small for the mean in unfiltered images (0.011) and for standard deviation (0.020-0.044) and entropy (0.040-0.044) in filtered images. Skewness and kurtosis in filtered images featuring medium and coarse textures were relatively variable across different CT scanners, with VIs of 0.638-0.692 and 0.430-0.437, respectively.Various quantitative CT texture parameters are robust and variable among different scanners, and the behavior of these parameters should be taken into consideration.

Postinjection single photon transmission tomography with ordered-subset algorithms for whole-body PET imaging

NASA Astrophysics Data System (ADS)

Bai, Chuanyong; Kinahan, P. E.; Brasse, D.; Comtat, C.; Townsend, D. W.

2002-02-01

We have evaluated the penalized ordered-subset transmission reconstruction (OSTR) algorithm for postinjection single photon transmission scanning. The OSTR algorithm of Erdogan and Fessler (1999) uses a more accurate model for transmission tomography than ordered-subsets expectation-maximization (OSEM) when OSEM is applied to the logarithm of the transmission data. The OSTR algorithm is directly applicable to postinjection transmission scanning with a single photon source, as emission contamination from the patient mimics the effect, in the original derivation of OSTR, of random coincidence contamination in a positron source transmission scan. Multiple noise realizations of simulated postinjection transmission data were reconstructed using OSTR, filtered backprojection (FBP), and OSEM algorithms. Due to the nonspecific task performance, or multiple uses, of the transmission image, multiple figures of merit were evaluated, including image noise, contrast, uniformity, and root mean square (rms) error. We show that: 1) the use of a three-dimensional (3-D) regularizing image roughness penalty with OSTR improves the tradeoffs in noise, contrast, and rms error relative to the use of a two-dimensional penalty; 2) OSTR with a 3-D penalty has improved tradeoffs in noise, contrast, and rms error relative to FBP or OSEM; and 3) the use of image standard deviation from a single realization to estimate the true noise can be misleading in the case of OSEM. We conclude that using OSTR with a 3-D penalty potentially allows for shorter postinjection transmission scans in single photon transmission tomography in positron emission tomography (PET) relative to FBP or OSEM reconstructed images with the same noise properties. This combination of singles+OSTR is particularly suitable for whole-body PET oncology imaging.

The value of FDG positron emission tomography/computerised tomography (PET/CT) in pre-operative staging of colorectal cancer: a systematic review and economic evaluation.

PubMed

Brush, J; Boyd, K; Chappell, F; Crawford, F; Dozier, M; Fenwick, E; Glanville, J; McIntosh, H; Renehan, A; Weller, D; Dunlop, M

2011-09-01

In the UK, colorectal cancer (CRC) is the third most common malignancy (behind lung and breast cancer) with 37,514 cases registered in 2006: around two-thirds (23,384) in the colon and one-third (14,130) in the rectum. Treatment of cancers of the colon can vary considerably, but surgical resection is the mainstay of treatment for curative intent. Following surgical resection, there is a comprehensive assessment of the tumour, it's invasion characteristics and spread (tumour staging). A number of imaging modalities are used in the pre-operative staging of CRCs including; computerised tomography (CT), magnetic resonance imaging, ultrasound imaging and positron emission tomography (PET). This report examines the role of CT in combination with PET scanning (PET/CT 'hybrid' scan). The research objectives are: to evaluate the diagnostic accuracy and therapeutic impact of fluorine-18-deoxyglucose (FDG) PET/CT for the pre-operative staging of primary, recurrent and metastatic cancer using systematic review methods; undertake probabilistic decision-analytic modelling (using Monte Carlo simulation); and conduct a value of information analysis to help inform whether or not there is potential worth in undertaking further research. For each aspect of the research - the systematic review, the handsearch study and the economic evaluation - a database was assembled from a comprehensive search for published and unpublished studies, which included database searches, reference lists search and contact with experts. In the systematic review prospective and retrospective patient series (diagnostic cohort) and randomised controlled trials (RCTs) were eligible for inclusion. Both consecutive series and series that are not explicitly reported as consecutive were included. Two reviewers extracted all data and applied the criteria independently and resolved disagreements by discussion. Data to populate 2 × 2 contingency tables consisting of the number of true positives, true negatives, false positives and false negatives using the studies' own definitions were extracted, as were data relating to changes in management. Fourteen items from the Quality Assessment of Diagnostic Accuracy Studies checklist were used to assess the methodological quality of the included studies. Patient-level data were used to calculate sensitivity and specificity with confidence intervals (CIs). Data were plotted graphically in forest plots. For the economic evaluation, economic models were designed for each of the disease states: primary, recurrent and metastatic. These were developed and populated based on a variety of information sources (in particular from published data sources) and literature, and in consultation with clinical experts. The review found 30 studies that met the eligibility criteria. Only two small studies evaluated the use of FDG PET/CT in primary CRC, and there is insufficient evidence to support its routine use at this time. The use of FDG PET/CT for the detection of recurrent disease identified data from five retrospective studies from which a pooled sensitivity of 91% (95% CI 0.87% to 0.95%) and specificity of 91% (95% CI 0.85% to 0.95%) were observed. Pooled accuracy data from patients undergoing staging for suspected metastatic disease showed FDG PET/CT to have a pooled sensitivity of 91% (95% CI 87% to 94%) and a specificity of 76% (95% CI 58% to 88%), but the poor quality of the studies means the validity of the data may be compromised by several biases. The separate handsearch study did not yield any additional unique studies relevant to FDG PET/CT. Models for recurrent disease demonstrated an incremental cost-effectiveness ratio of £ 21,409 per quality-adjusted life-year (QALY) for rectal cancer, £ 6189 per QALY for colon cancer and £ 21,434 per QALY for metastatic disease. The value of handsearching to identify studies of less clearly defined or reported diagnostic tests is still to be investigated. The systematic review found insufficient evidence to support the routine use of FDG PET/CT in primary CRC and only a small amount of evidence supporting its use in the pre-operative staging of recurrent and metastatic CRC, and, although FDG PET/CT was shown to change patient management, the data are divergent and the quality of research is generally poor. The handsearch to identify studies of less clearly defined or reported diagnostic tests did not find additional studies. The primary limitations in the economic evaluations were due to uncertainty and lack of available evidence from the systematic reviews for key parameters in each of the five models. In order to address this, a conservative approach was adopted in choosing DTA estimates for the model parameters. Probabilistic analyses were undertaken for each of the models, incorporating wide levels of uncertainty particularly for the DTA estimates. None of the economic models reported cost-savings, but the approach adopted was conservative in order to determine more reliable results given the lack of current information. The economic evaluations conclude that FDG PET/CT as an add-on imaging device is cost-effective in the pre-operative staging of recurrent colon, recurrent rectal and metastatic disease but not in primary colon or rectal cancers. There would be value in undertaking an RCT with a concurrent economic evaluation to evaluate the therapeutic impact and cost-effectiveness of FDG PET/CT compared with conventional imaging (without PET) for the pre-operative staging of recurrent and metastatic CRC.

INRstar: computerised decision support software for anticoagulation management in primary care.

PubMed

Jones, Robert Treharne; Sullivan, Mark; Barrett, David

2005-01-01

Computerised decision support software (CDSS) for anticoagulation management has become established practice in the UK, offering significant advantages for patients and clinicians over traditional methods of dose calculation. The New GMS Contract has been partly responsible for this shift of management from secondary to primary care, in which INRstar has been the market leader for many years. In September 2004, INRstar received the John Perry Prize, awarded by the PHCSG for excellence and innovation in medical applications of information technology.

11C-Methionine Positron Emission Tomography/Computed Tomography Versus 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Evaluation of Residual or Recurrent World Health Organization Grades II and III Meningioma After Treatment.

PubMed

Tomura, Noriaki; Saginoya, Toshiyuki; Goto, Hiromi

2018-04-02

The aim of this study was to determine the assessment of positron emission tomography-computed tomography using C-methionine (MET PET/CT) for World Health Organization (WHO) grades II and III meningiomas; MET PET/CT was compared with PET/CT using F-fluorodeoxy glucose (FDG PET/CT). This study was performed in 17 cases with residual and/or recurrent WHO grades II and III meningiomas. Two neuroradiologists reviewed both PET/CT scans. For agreement, the κ coefficient was measured. Difference in tumor-to-normal brain uptake ratios (T/N ratios) between 2 PET/CT scans was analyzed. Correlation between the maximum tumor size and T/N ratio in PET/CT was studied. For agreement by both reviewers, the κ coefficient was 0.51 (P < 0.05). The T/N ratio was significantly higher for MET PET/CT (3.24 ± 1.36) than for FDG PET/CT (0.93 ± 0.44) (P < 0.01). C-methionine ratio significantly correlated with tumor size (y = 8.1x + 16.3, n = 22, P < 0.05), but FDG ratio did not CONCLUSIONS: C-methionine PET/CT has superior potential for imaging of WHO grades II and III meningiomas with residual or recurrent tumors compared with FDG PET/CT.

Unenhanced 320-row multidetector computed tomography of the brain in children: comparison of image quality and radiation dose among wide-volume, one-shot volume, and helical scan modes.

PubMed

Jeon, Sun Kyung; Choi, Young Hun; Cheon, Jung-Eun; Kim, Woo Sun; Cho, Yeon Jin; Ha, Ji Young; Lee, Seung Hyun; Hyun, Hyejin; Kim, In-One

2018-04-01

The 320-row multidetector computed tomography (CT) scanner has multiple scan modes, including volumetric modes. To compare the image quality and radiation dose of 320-row CT in three acquisition modes - helical, one-shot volume, and wide-volume scan - at pediatric brain imaging. Fifty-seven children underwent unenhanced brain CT using one of three scan modes (helical scan, n=21; one-shot volume scan, n=17; wide-volume scan, n=19). For qualitative analysis, two reviewers evaluated overall image quality and image noise using a 5-point grading system. For quantitative analysis, signal-to-noise ratio, image noise and posterior fossa artifact index were calculated. To measure the radiation dose, adjusted CT dose index per unit volume (CTDI adj ) and dose length product (DLP) were compared. Qualitatively, the wide-volume scan showed significantly less image noise than the helical scan (P=0.009), and less streak artifact than the one-shot volume scan (P=0.001). The helical mode showed significantly lower signal-to-noise ratio, with a higher image noise level compared with the one-shot volume and wide-volume modes (all P<0.05). The CTDI adj and DLP were significantly lower in the one-shot volume and wide-volume modes compared with those in the helical scan mode (all P<0.05). For pediatric unenhanced brain CT, both the wide-volume and one-shot volume scans reduced radiation dose compared to the helical scan mode, while the wide-volume scan mode showed fewer streak artifacts in the skull vertex and posterior fossa than the one-shot volume scan.

Isotropic-resolution linear-array-based photoacoustic computed tomography through inverse Radon transform

NASA Astrophysics Data System (ADS)

Li, Guo; Xia, Jun; Li, Lei; Wang, Lidai; Wang, Lihong V.

2015-03-01

Linear transducer arrays are readily available for ultrasonic detection in photoacoustic computed tomography. They offer low cost, hand-held convenience, and conventional ultrasonic imaging. However, the elevational resolution of linear transducer arrays, which is usually determined by the weak focus of the cylindrical acoustic lens, is about one order of magnitude worse than the in-plane axial and lateral spatial resolutions. Therefore, conventional linear scanning along the elevational direction cannot provide high-quality three-dimensional photoacoustic images due to the anisotropic spatial resolutions. Here we propose an innovative method to achieve isotropic resolutions for three-dimensional photoacoustic images through combined linear and rotational scanning. In each scan step, we first elevationally scan the linear transducer array, and then rotate the linear transducer array along its center in small steps, and scan again until 180 degrees have been covered. To reconstruct isotropic three-dimensional images from the multiple-directional scanning dataset, we use the standard inverse Radon transform originating from X-ray CT. We acquired a three-dimensional microsphere phantom image through the inverse Radon transform method and compared it with a single-elevational-scan three-dimensional image. The comparison shows that our method improves the elevational resolution by up to one order of magnitude, approaching the in-plane lateral-direction resolution. In vivo rat images were also acquired.

Cerebral glucose metabolism and cognition in newly diagnosed Parkinson's disease: ICICLE-PD study.

PubMed

Firbank, M J; Yarnall, A J; Lawson, R A; Duncan, G W; Khoo, T K; Petrides, G S; O'Brien, J T; Barker, R A; Maxwell, R J; Brooks, D J; Burn, D J

2017-04-01

To assess reductions of cerebral glucose metabolism in Parkinson's disease (PD) with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), and their associations with cognitive decline. FDG-PET was performed on a cohort of 79 patients with newly diagnosed PD (mean disease duration 8 months) and 20 unrelated controls. PD participants were scanned while on their usual dopaminergic medication. Cognitive testing was performed at baseline, and after 18 months using the Cognitive Drug Research (CDR) and Cambridge Neuropsychological Test Automated Battery (CANTAB) computerised batteries, the Mini-Mental State Examination (MMSE), and the Montreal Cognitive Assessment (MoCA). We used statistical parametric mapping (SPM V.12) software to compare groups and investigate voxelwise correlations between FDG metabolism and cognitive score at baseline. Linear regression was used to evaluate how levels of cortical FDG metabolism were predictive of subsequent cognitive decline rated with the MMSE and MoCA. PD participants showed reduced glucose metabolism in the occipital and inferior parietal lobes relative to controls. Low performance on memory-based tasks was associated with reduced FDG metabolism in posterior parietal and temporal regions, while attentional performance was associated with more frontal deficits. Baseline parietal to cerebellum FDG metabolism ratios predicted MMSE (β=0.38, p=0.001) and MoCA (β=0.3, p=0.002) at 18 months controlling for baseline score. Reductions in cortical FDG metabolism were present in newly diagnosed PD, and correlated with performance on neuropsychological tests. A reduced baseline parietal metabolism is associated with risk of cognitive decline and may represent a potential biomarker for this state and the development of PD dementia. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Treatment concept of chronic subdural haematoma according to an algorithm using evidence-based medicine-derived key factors: A prospective controlled study.

PubMed

Weigel, Ralf; Schlickum, Linda; Weisser, Gerald; Krauss, Joachim K

2015-01-01

Surgical treatment for chronic subdural haematoma (CSH) has been analysed by applying evidence-based medicine (EBM) criteria earlier. Whether implementation of EBM-derived key factors into an optimised treatment algorithm would improve outcome, however, needs to be clarified. Symptomatic patients with CSH who fulfilled the inclusion criteria were either assigned to an optimised treatment algorithm (OA-EBM group) or to a control group treated by the standard departmental surgical technique (SDST group) in a prospective design. For the OA-EBM algorithm only one burr hole, extensive intraoperative irrigation and a closed system drainage with meticulous avoidance of entry of air was mandatory. A two-catheter technique was used to reduce intracavital air. Final endpoints were neurological outcome (Markwalder Score), recurrence and the amount of intracranial air. A total of 93 out of 117 patients were evaluated accounting for 113 cases because 20 patients had bilateral haematomas. Demographic data of 68 cases in the SDST group did not differ from 45 cases in the OA-EBM group. The Markwalder Score showed greater improvement in the OA-EBM group (0.5 ± 0.6 vs. 1.0 ± 1.0, p = 0.003). The recurrence rate was 18% (12 patients) in the SDST group versus 2% (1 patient) in the OA-EBM group (p < 0.05). The amount of intracranial air was significantly lower in the OA-EBM group (3.3 ± 5.0 cm(3) vs. 5.2 ± 7.7 cm(3)) with p = 0.04. In the standard group computerised tomography scanning was performed slightly earlier (3 ± 1.7 days vs. 3.6 ± 1.4 days). When comparing only non-recurrent cases in both groups no significant difference was apparent. Implementation of EBM key factors into a treatment algorithm for CSH can improve neurological outcome in a typical neurosurgical department, reduce recurrence and minimise the amount of postoperative air within the haematoma cavity.

Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography.

PubMed

Kim, Jooseong; Heo, Giseon; Lagravère, Manuel O

2014-05-01

To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm. In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

Attenuation-difference radar tomography: results of a multiple-plane experiment at the U.S. Geological Survey Fractured-Rock Research Site, Mirror Lake, New Hampshire

USGS Publications Warehouse

Lane, J.W.; Day-Lewis, F. D.; Harris, J.M.; Haeni, F.P.; Gorelick, S.M.

2000-01-01

Attenuation-difference, borehole-radar tomography was used to monitor a series of sodium chloride tracer injection tests conducted within the FSE, wellfield at the U.S. Geological Survey Fractured-Rock Hydrology Research Site in Grafton County, New Hampshire, USA. Borehole-radar tomography surveys were conducted using the sequential-scanning and injection method in three boreholes that form a triangular prism of adjoining tomographic image planes. Results indicate that time-lapse tomography methods provide high-resolution images of tracer distribution in permeable zones.

256 Slice Multi-detector Computed Tomography Thoracic Aorta Computed Tomography Angiography: Improved Luminal Opacification Using a Patient-Specific Contrast Protocol and Caudocranial Scan Acquisition.

PubMed

Saade, Charbel; El-Merhi, Fadi; El-Achkar, Bassam; Kerek, Racha; Vogl, Thomas J; Maroun, Gilbert Georges; Jamjoom, Lamia; Al-Mohiy, Hussain; Naffaa, Lena

Caudocranial scan direction and contrast injection timing based on measured patient vessel dynamics can significantly improve arterial and aneurysmal opacification and reduce both contrast and radiation dose in the assessment of thoracic aortic aneurysms (TAA) using helical thoracic computed tomography angiography (CTA). To investigate opacification of the thoracic aorta and TAA using a caudocranial scan direction and a patient-specific contrast protocol. Thoracic aortic CTA was performed in 160 consecutive patients with suspected TAA using a 256-slice computed tomography scanner and a dual barrel contrast injector. Patients were subjected in equal numbers to one of two contrast protocols. Patient age and sex were equally distributed across both groups. Protocol A, the department's standard protocol, consisted of a craniocaudal scan direction with 100 mL of contrast, intravenously injected at a flow rate of 4.5 mL/s. Protocol B involved a caudocranial scan direction and a novel contrast formula based on patient cardiovascular dynamics, followed by 100 mL of saline at 4.5 mL/s. Each scan acquisition comprised of 120 kVp, 200 mA with modulation, temporal resolution 0.27 seconds, and pitch 0.889:1. The dose length product was measured between each protocol and data generated were compared using Mann-Whitney U nonparametric statistics. Receiver operating characteristic analysis, visual grading characteristic (VGC), and κ analyses were performed. Mean opacification in the thoracic aorta and aneurysm measured was 24 % and 55%, respectively. The mean contrast volume was significantly lower in protocol B (73 ± 10 mL) compared with A (100 ± 1 mL) (P<0.001). The contrast-to-noise ratio demonstrated significant differences between the protocols (protocol A, 18.2 ± 12.9; protocol B, 29.7 ± 0.61; P < 0.003). Mean effective dose in protocol B (2.6 ± 0.4 mSv) was reduced by 19% compared with A (3.2 ± 0.8 mSv) (P < 0.004). Aneurysmal detectability demonstrated significant increases by receiver operating characteristic and visual grading characteristic analysis for protocol B compared with A (P < 0.02), and reader agreement increased from poor to excellent. Significant increase in the visualization of TAAs following a caudocranial scan direction during helical thoracic CTA can be achieved using low-contrast volume based on patient-specific contrast formula.

Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo

PubMed Central

Liang, Kaicheng; Wang, Zhao; Ahsen, Osman O.; Lee, Hsiang-Chieh; Potsaid, Benjamin M.; Jayaraman, Vijaysekhar; Cable, Alex; Mashimo, Hiroshi; Li, Xingde; Fujimoto, James G.

2018-01-01

Devices that perform wide field-of-view (FOV) precision optical scanning are important for endoscopic assessment and diagnosis of luminal organ disease such as in gastroenterology. Optical scanning for in vivo endoscopic imaging has traditionally relied on one or more proximal mechanical actuators, limiting scan accuracy and imaging speed. There is a need for rapid and precise two-dimensional (2D) microscanning technologies to enable the translation of benchtop scanning microscopies to in vivo endoscopic imaging. We demonstrate a new cycloid scanner in a tethered capsule for ultrahigh speed, side-viewing optical coherence tomography (OCT) endomicroscopy in vivo. The cycloid capsule incorporates two scanners: a piezoelectrically actuated resonant fiber scanner to perform a precision, small FOV, fast scan and a micromotor scanner to perform a wide FOV, slow scan. Together these scanners distally scan the beam circumferentially in a 2D cycloid pattern, generating an unwrapped 1 mm × 38 mm strip FOV. Sequential strip volumes can be acquired with proximal pullback to image centimeter-long regions. Using ultrahigh speed 1.3 μm wavelength swept-source OCT at a 1.17 MHz axial scan rate, we imaged the human rectum at 3 volumes/s. Each OCT strip volume had 166 × 2322 axial scans with 8.5 μm axial and 30 μm transverse resolution. We further demonstrate OCT angiography at 0.5 volumes/s, producing volumetric images of vasculature. In addition to OCT applications, cycloid scanning promises to enable precision 2D optical scanning for other imaging modalities, including fluorescence confocal and nonlinear microscopy. PMID:29682598

Abernethy malformation with portal vein aneurysm in a child.

PubMed

Chandrashekhara, Sheragaru H; Bhalla, Ashu Seith; Gupta, Arun Kumar; Vikash, C S; Kabra, Susheel Kumar

2011-01-01

Abernethy malformation is an extremely rare anomaly of the splanchnic venous system. We describe multidetector computed tomography findings of an incidentally detected Abernethy malformation with portal vein aneurysm in a two-and-half-year old child. The computed tomography scan was performed for the evaluation of respiratory distress, poor growth, and loss of appetite.

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.

Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment.

PubMed

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; Motroni, Alessandro; van der Stelt, Paul; Wismeijer, Daniel

2012-01-01

To assess the reliability of cone beam computed tomography (CBCT) voxel gray value measurements using Hounsfield units (HU) derived from multislice computed tomography (MSCT) as a clinical reference (gold standard). Ten partially edentulous human mandibular cadavers were scanned by two types of computed tomography (CT) modalities: multislice CT and cone beam CT. On MSCT scans, eight regions of interest (ROI) designating the site for preoperative implant placement were selected in each mandible. The datasets from both CT systems were matched using a three-dimensional (3D) registration algorithm. The mean voxel gray values of the region around the implant sites were compared between MSCT and CBCT. Significant differences between the mean gray values obtained by CBCT and HU by MSCT were found. In all the selected ROIs, CBCT showed higher mean values than MSCT. A strong correlation (R=0.968) between mean voxel gray values of CBCT and mean HU of MSCT was determined. Voxel gray values from CBCT deviate from actual HU units. However, a strong linear correlation exists, which may permit deriving actual HU units from CBCT using linear regression models.

Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

DOE PAGES

Levin, Barnaby D. A.; Padgett, Elliot; Chen, Chien-Chun; ...

2016-06-07

Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co 2 P nanocrystal, platinum nanoparticles on a carbonmore » nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.« less

Nanomaterial datasets to advance tomography in scanning transmission electron microscopy.

PubMed

Levin, Barnaby D A; Padgett, Elliot; Chen, Chien-Chun; Scott, M C; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D; Robinson, Richard D; Ercius, Peter; Kourkoutis, Lena F; Miao, Jianwei; Muller, David A; Hovden, Robert

2016-06-07

Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.

Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

PubMed Central

Levin, Barnaby D.A.; Padgett, Elliot; Chen, Chien-Chun; Scott, M.C.; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D.; Robinson, Richard D.; Ercius, Peter; Kourkoutis, Lena F.; Miao, Jianwei; Muller, David A.; Hovden, Robert

2016-01-01

Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data. PMID:27272459

Three-Dimensional Optical Coherence Tomography

NASA Technical Reports Server (NTRS)

Gutin, Mikhail; Wang, Xu-Ming; Gutin, Olga

2009-01-01

Three-dimensional (3D) optical coherence tomography (OCT) is an advanced method of noninvasive infrared imaging of tissues in depth. Heretofore, commercial OCT systems for 3D imaging have been designed principally for external ophthalmological examination. As explained below, such systems have been based on a one-dimensional OCT principle, and in the operation of such a system, 3D imaging is accomplished partly by means of a combination of electronic scanning along the optical (Z) axis and mechanical scanning along the two axes (X and Y) orthogonal to the optical axis. In 3D OCT, 3D imaging involves a form of electronic scanning (without mechanical scanning) along all three axes. Consequently, the need for mechanical adjustment is minimal and the mechanism used to position the OCT probe can be correspondingly more compact. A 3D OCT system also includes a probe of improved design and utilizes advanced signal- processing techniques. Improvements in performance over prior OCT systems include finer resolution, greater speed, and greater depth of field.

Spectral domain optical coherence tomography of multi-MHz A-scan rates at 1310 nm range and real-time 4D-display up to 41 volumes/second

PubMed Central

Choi, Dong-hak; Hiro-Oka, Hideaki; Shimizu, Kimiya; Ohbayashi, Kohji

2012-01-01

An ultrafast frequency domain optical coherence tomography system was developed at A-scan rates between 2.5 and 10 MHz, a B-scan rate of 4 or 8 kHz, and volume-rates between 12 and 41 volumes/second. In the case of the worst duty ratio of 10%, the averaged A-scan rate was 1 MHz. Two optical demultiplexers at a center wavelength of 1310 nm were used for linear-k spectral dispersion and simultaneous differential signal detection at 320 wavelengths. The depth-range, sensitivity, sensitivity roll-off by 6 dB, and axial resolution were 4 mm, 97 dB, 6 mm, and 23 μm, respectively. Using FPGAs for FFT and a GPU for volume rendering, a real-time 4D display was demonstrated at a rate up to 41 volumes/second for an image size of 256 (axial) × 128 × 128 (lateral) voxels. PMID:23243560

Evaluation of the accuracy of linear measurements on multi-slice and cone beam computed tomography scans to detect the mandibular canal during bilateral sagittal split osteotomy of the mandible.

PubMed

Freire-Maia, B; Machado, V deC; Valerio, C S; Custódio, A L N; Manzi, F R; Junqueira, J L C

2017-03-01

The aim of this study was to compare the accuracy of linear measurements of the distance between the mandibular cortical bone and the mandibular canal using 64-detector multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT). It was sought to evaluate the reliability of these examinations in detecting the mandibular canal for use in bilateral sagittal split osteotomy (BSSO) planning. Eight dry human mandibles were studied. Three sites, corresponding to the lingula, the angle, and the body of the mandible, were selected. After the CT scans had been obtained, the mandibles were sectioned and the bone segments measured to obtain the actual measurements. On analysis, no statistically significant difference was found between the measurements obtained through MSCT and CBCT, or when comparing the measurements from these scans with the actual measurements. It is concluded that the images obtained by CT scan, both 64-detector multi-slice and cone beam, can be used to obtain accurate linear measurements to locate the mandibular canal for preoperative planning of BSSO. The ability to correctly locate the mandibular canal during BSSO will reduce the occurrence of neurosensory disturbances in the postoperative period. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Analysis of intensity variability in multislice and cone beam computed tomography.

PubMed

Nackaerts, Olivia; Maes, Frederik; Yan, Hua; Couto Souza, Paulo; Pauwels, Ruben; Jacobs, Reinhilde

2011-08-01

The aim of this study was to evaluate the variability of intensity values in cone beam computed tomography (CBCT) imaging compared with multislice computed tomography Hounsfield units (MSCT HU) in order to assess the reliability of density assessments using CBCT images. A quality control phantom was scanned with an MSCT scanner and five CBCT scanners. In one CBCT scanner, the phantom was scanned repeatedly in the same and in different positions. Images were analyzed using registration to a mathematical model. MSCT images were used as a reference. Density profiles of MSCT showed stable HU values, whereas in CBCT imaging the intensity values were variable over the profile. Repositioning of the phantom resulted in large fluctuations in intensity values. The use of intensity values in CBCT images is not reliable, because the values are influenced by device, imaging parameters and positioning. © 2011 John Wiley & Sons A/S.

Ultra-structural study of insulin granules in pancreatic β-cells of db/db mouse by scanning transmission electron microscopy tomography.

PubMed

Xue, Yanhong; Zhao, Wei; Du, Wen; Zhang, Xiang; Ji, Gang; Ying, Wang; Xu, Tao

2012-07-01

Insulin granule trafficking is a key step in the secretion of glucose-stimulated insulin from pancreatic β-cells. The main feature of type 2 diabetes (T2D) is the failure of pancreatic β-cells to secrete sufficient amounts of insulin to maintain normal blood glucose levels. In this work, we developed and applied tomography based on scanning transmission electron microscopy (STEM) to image intact insulin granules in the β-cells of mouse pancreatic islets. Using three-dimensional (3D) reconstruction, we found decreases in both the number and the grey level of insulin granules in db/db mouse pancreatic β-cells. Moreover, insulin granules were closer to the plasma membrane in diabetic β-cells than in control cells. Thus, 3D ultra-structural tomography may provide new insights into the pathology of insulin secretion in T2D.

Early prosthetic aortic valve infection identified with the use of positron emission tomography in a patient with lead endocarditis.

PubMed

Amraoui, Sana; Tlili, Ghoufrane; Sohal, Manav; Bordenave, Laurence; Bordachar, Pierre

2016-12-01

18-Fluorodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) scanning has recently been proposed as a diagnostic tool for lead endocarditis (LE). FDG PET/CT might be also useful to localize associated septic emboli in patients with LE. We report an interesting case of a LE patient with a prosthetic aortic valve in whom a trans-esophageal echocardiogram did not show associated aortic endocarditis. FDG PET/CT revealed prosthetic aortic valve infection. A second TEE performed 2 weeks after identified aortic vegetation. A longer duration of antimicrobial therapy with serial follow-up echocardiography was initiated. There was also increased uptake in the sigmoid colon, corresponding to focal polyps resected during a colonoscopy. FDG PET/CT scanning seems to be highly sensitive for prosthetic aortic valve endocarditis diagnosis. This promising diagnostic tool may be beneficial in LE patients, by identifying septic emboli and potential sites of pathogen entry.

Thyroid cartilage invasion in laryngeal and hypopharyngeal squamous cell carcinoma treated with total laryngectomy.

PubMed

Koopmann, Mario; Weiss, Daniel; Steiger, Matthias; Elges, Sandra; Rudack, Claudia; Stenner, Markus

2016-11-01

The objective of this study is to analyze the accuracy of computed tomography in detecting malignant thyroid cartilage invasion. In a retrospective chart review, 120 patients with carcinoma of the larynx and hypopharynx underwent computed tomography before total laryngectomy. These data were compared with the histological specimens. Multidetector computed tomography (MDCT) scan had a positive predictive value (PPV) of 76 % and a negative predictive value (NPV) of 69 %. The specificity of MDCT was 89 % and sensitivity was 46 %. Comparison between radiologic suspected cartilage invasion and histologic results showed a significant correlation (p < 0.02). We found no significant impact of cartilage invasion concerning survival rates (5-year overall survival p = 0.683; 5-year disease-free survival p = 0.711). Preoperative CT scan is an important instrument in detecting neoplastic cartilage invasion.

Generalized subcutaneous edema as a rare manifestation of dermatomyositis: clinical lesson from a rare feature.

PubMed

Haroon, Muhammad; Eltahir, Ahmed; Harney, Sinead

2011-04-01

Generalized subcutaneous edema is a very rare manifestation of inflammatory myopathies. A 61-year-old woman presented with classic signs and symptoms of dermatomyositis. She was also noted to have generalized edema that was so florid that an alternative diagnosis was considered. Her disease was resistant to corticosteroids, azathioprine, and mycophenolate mofetil. Intravenous administration of immunoglobulins was started because of marked worsening of her disease-muscle weakness, generalized anasarca, and involvement of her bulbar muscles. This led to dramatic resolution of her subcutaneous edema and significant improvement of her skin and muscle disease. As the initial screen for malignancy was negative, a positron emission tomography-computed tomography scan was requested, which interestingly showed a metabolically active cervical tumor. Anasarca is an unusual manifestation of dermatomyositis. In treatment-refractory cases, it seems reasonable to consider positron emission tomography scan in excluding underlying malignant disease.

Evaluation of dose from kV cone-beam computed tomography during radiotherapy: a comparison of methodologies

NASA Astrophysics Data System (ADS)

Buckley, J.; Wilkinson, D.; Malaroda, A.; Metcalfe, P.

2017-01-01

Three alternative methodologies to the Computed-Tomography Dose Index for the evaluation of Cone-Beam Computed Tomography dose are compared, the Cone-Beam Dose Index, IAEA Human Health Report No. 5 recommended methodology and the AAPM Task Group 111 recommended methodology. The protocols were evaluated for Pelvis and Thorax scan modes on Varian® On-Board Imager and Truebeam kV XI imaging systems. The weighted planar average dose was highest for the AAPM methodology across all scans, with the CBDI being the second highest overall. A 17.96% and 1.14% decrease from the TG-111 protocol to the IAEA and CBDI protocols for the Pelvis mode and 18.15% and 13.10% decrease for the Thorax mode were observed for the XI system. For the OBI system, the variation was 16.46% and 7.14% for Pelvis mode and 15.93% to the CBDI protocol in Thorax mode respectively.

Dark-count-less photon-counting x-ray computed tomography system using a YAP-MPPC detector

NASA Astrophysics Data System (ADS)

Sato, Eiichi; Sato, Yuich; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2012-10-01

A high-sensitive X-ray computed tomography (CT) system is useful for decreasing absorbed dose for patients, and a dark-count-less photon-counting CT system was developed. X-ray photons are detected using a YAP(Ce) [cerium-doped yttrium aluminum perovskite] single crystal scintillator and an MPPC (multipixel photon counter). Photocurrents are amplified by a high-speed current-voltage amplifier, and smooth event pulses from an integrator are sent to a high-speed comparator. Then, logical pulses are produced from the comparator and are counted by a counter card. Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. The image contrast of gadolinium medium slightly fell with increase in lower-level voltage (Vl) of the comparator. The dark count rate was 0 cps, and the count rate for the CT was approximately 250 kcps.

High-speed optical coherence tomography using fiberoptic acousto-optic phase modulation

NASA Astrophysics Data System (ADS)

Xie, Tuqiang; Wang, Zhenguo; Pan, Yingtian

2003-12-01

We report a new rapid-scanning optical delay device suitable for high-speed optical coherence tomography (OCT) in which an acousto-optic modulator (AOM) is used to independently modulate the Doppler frequency shift of the reference light beam for optical heterodyne detection. Experimental results show that the fluctuation of the measured Doppler frequency shift is less than +/-0.2% over 95% duty cycle of OCT imaging, thus allowing for enhanced signal-to-noise ratio of optical heterodyne detection. The increased Doppler frequency shift by AOM also permits complete envelop demodulation without the compromise of reducing axial resolution; if used with a resonant rapid-scanning optical delay, it will permit high-performance real-time OCT imaging. Potentially, this new rapid-scanning optical delay device will improve the performance of high-speed Doppler OCT techniques.

ViRPET--combination of virtual reality and PET brain imaging

DOEpatents

Majewski, Stanislaw; Brefczynski-Lewis, Julie

2017-05-23

Various methods, systems and apparatus are provided for brain imaging during virtual reality stimulation. In one example, among others, a system for virtual ambulatory environment brain imaging includes a mobile brain imager configured to obtain positron emission tomography (PET) scans of a subject in motion, and a virtual reality (VR) system configured to provide one or more stimuli to the subject during the PET scans. In another example, a method for virtual ambulatory environment brain imaging includes providing stimulation to a subject through a virtual reality (VR) system; and obtaining a positron emission tomography (PET) scan of the subject while moving in response to the stimulation from the VR system. The mobile brain imager can be positioned on the subject with an array of imaging photodetector modules distributed about the head of the subject.

The Role of Computed Tomography in Blunt Abdominal Trauma.

PubMed

Karki, O B

2015-01-01

Blunt injury trauma is regularly encountered in the emergency department. Diagnostic tools that help in optimum management of blunt abdominal trauma include; Focussed Assessment Sonography for Trauma scan, Diagnostic peritoneal lavage and Computed Tomography scan. The aim of this study is to determine the validity of CT scan as an accurate diagnostic tool and its role in management of patients with blunt abdominal trauma. A prospective analysis of 80 patients of blunt abdomen trauma who were admitted in Manipal Teaching Hospital, Pokhara, Nepal within a span of 15 months was done. Demographic data, mechanism of trauma, management and outcomes were studied. Organ injuries were graded using the Organ Injury Scale guidelines. Most of the patients in our study were in the age group of 21-40 years with an M: F ratio of 2.3:1. Road traffic accident (47.5%) was the most common mechanism of injury. Spleen (27.5%) was the commonest organ injured. CT scan was superior to FAST scan and had sensitivity of 97.3% specificity 75% positive predictive value 98.6%. FAST scan had sensitivity of 78.9%, specificity 50%, positive predictive value 96% with p- value of 0.0034. 81% of patients were conservatively managed. In conjunction with close clinical monitoring, CT scan is reliable in the evaluation and management of blunt abdominal trauma patients. Our study also shows CT as a superior diagnostic modality compared to FAST scan.

Improved Visualization of Glaucomatous Retinal Damage Using High-speed Ultrahigh-Resolution Optical Coherence Tomography

PubMed Central

Mumcuoglu, Tarkan; Wollstein, Gadi; Wojtkowski, Maciej; Kagemann, Larry; Ishikawa, Hiroshi; Gabriele, Michelle L.; Srinivasan, Vivek; Fujimoto, James G.; Duker, Jay S.; Schuman, Joel S.

2009-01-01

Purpose To test if improving optical coherence tomography (OCT) resolution and scanning speed improves the visualization of glaucomatous structural changes as compared with conventional OCT. Design Prospective observational case series. Participants Healthy and glaucomatous subjects in various stages of disease. Methods Subjects were scanned at a single visit with commercially available OCT (StratusOCT) and high-speed ultrahigh-resolution (hsUHR) OCT. The prototype hsUHR OCT had an axial resolution of 3.4 μm (3 times higher than StratusOCT), with an A-scan rate of 24 000 hertz (60 times faster than StratusOCT). The fast scanning rate allowed the acquisition of novel scanning patterns such as raster scanning, which provided dense coverage of the retina and optic nerve head. Main Outcome Measures Discrimination of retinal tissue layers and detailed visualization of retinal structures. Results High-speed UHR OCT provided a marked improvement in tissue visualization as compared with StratusOCT. This allowed the identification of numerous retinal layers, including the ganglion cell layer, which is specifically prone to glaucomatous damage. Fast scanning and the enhanced A-scan registration properties of hsUHR OCT provided maps of the macula and optic nerve head with unprecedented detail, including en face OCT fundus images and retinal nerve fiber layer thickness maps. Conclusion High-speed UHR OCT improves visualization of the tissues relevant to the detection and management of glaucoma. PMID:17884170

Evaluation of Retinal and Choroidal Thickness by Swept-Source Optical Coherence Tomography: Repeatability and Assessment of Artifacts

PubMed Central

Mansouri, Kaweh; Medeiros, Felipe A.; Tatham, Andrew J.; Marchase, Nicholas; Weinreb, Robert N.

2017-01-01

PURPOSE To determine the repeatability of automated retinal and choroidal thickness measurements with swept-source optical coherence tomography (SS OCT) and the frequency and type of scan artifacts. DESIGN Prospective evaluation of new diagnostic technology. METHODS Thirty healthy subjects were recruited prospectively and underwent imaging with a prototype SS OCT instrument. Undilated scans of 54 eyes of 27 subjects (mean age, 35.1 ± 9.3 years) were obtained. Each subject had 4 SS OCT protocols repeated 3 times: 3-dimensional (3D) 6 × 6-mm raster scan of the optic disc and macula, radial, and line scan. Automated measurements were obtained through segmentation software. Interscan repeatability was assessed by intraclass correlation coefficients (ICCs). RESULTS ICCs for choroidal measurements were 0.92, 0.98, 0.80, and 0.91, respectively, for 3D macula, 3D optic disc, radial, and line scans. ICCs for retinal measurements were 0.39, 0.49, 0.71, and 0.69, respectively. Artifacts were present in up to 9% scans. Signal loss because of blinking was the most common artifact on 3D scans (optic disc scan, 7%; macula scan, 9%), whereas segmentation failure occurred in 4% of radial and 3% of line scans. When scans with image artifacts were excluded, ICCs for choroidal thickness increased to 0.95, 0.99, 0.87, and 0.93 for 3D macula, 3D optic disc, radial, and line scans, respectively. ICCs for retinal thickness increased to 0.88, 0.83, 0.89, and 0.76, respectively. CONCLUSIONS Improved repeatability of automated choroidal and retinal thickness measurements was found with the SS OCT after correction of scan artifacts. Recognition of scan artifacts is important for correct interpretation of SS OCT measurements. PMID:24531020

Advantages and Disadvantages in Image Processing with Free Software in Radiology.

PubMed

Mujika, Katrin Muradas; Méndez, Juan Antonio Juanes; de Miguel, Andrés Framiñan

2018-01-15

Currently, there are sophisticated applications that make it possible to visualize medical images and even to manipulate them. These software applications are of great interest, both from a teaching and a radiological perspective. In addition, some of these applications are known as Free Open Source Software because they are free and the source code is freely available, and therefore it can be easily obtained even on personal computers. Two examples of free open source software are Osirix Lite® and 3D Slicer®. However, this last group of free applications have limitations in its use. For the radiological field, manipulating and post-processing images is increasingly important. Consequently, sophisticated computing tools that combine software and hardware to process medical images are needed. In radiology, graphic workstations allow their users to process, review, analyse, communicate and exchange multidimensional digital images acquired with different image-capturing radiological devices. These radiological devices are basically CT (Computerised Tomography), MRI (Magnetic Resonance Imaging), PET (Positron Emission Tomography), etc. Nevertheless, the programs included in these workstations have a high cost which always depends on the software provider and is always subject to its norms and requirements. With this study, we aim to present the advantages and disadvantages of these radiological image visualization systems in the advanced management of radiological studies. We will compare the features of the VITREA2® and AW VolumeShare 5® radiology workstation with free open source software applications like OsiriX® and 3D Slicer®, with examples from specific studies.

Comparison of 3D cellular imaging techniques based on scanned electron probes: Serial block face SEM vs. Axial bright-field STEM tomography.

PubMed

McBride, E L; Rao, A; Zhang, G; Hoyne, J D; Calco, G N; Kuo, B C; He, Q; Prince, A A; Pokrovskaya, I D; Storrie, B; Sousa, A A; Aronova, M A; Leapman, R D

2018-06-01

Microscopies based on focused electron probes allow the cell biologist to image the 3D ultrastructure of eukaryotic cells and tissues extending over large volumes, thus providing new insight into the relationship between cellular architecture and function of organelles. Here we compare two such techniques: electron tomography in conjunction with axial bright-field scanning transmission electron microscopy (BF-STEM), and serial block face scanning electron microscopy (SBF-SEM). The advantages and limitations of each technique are illustrated by their application to determining the 3D ultrastructure of human blood platelets, by considering specimen geometry, specimen preparation, beam damage and image processing methods. Many features of the complex membranes composing the platelet organelles can be determined from both approaches, although STEM tomography offers a higher ∼3 nm isotropic pixel size, compared with ∼5 nm for SBF-SEM in the plane of the block face and ∼30 nm in the perpendicular direction. In this regard, we demonstrate that STEM tomography is advantageous for visualizing the platelet canalicular system, which consists of an interconnected network of narrow (∼50-100 nm) membranous cisternae. In contrast, SBF-SEM enables visualization of complete platelets, each of which extends ∼2 µm in minimum dimension, whereas BF-STEM tomography can typically only visualize approximately half of the platelet volume due to a rapid non-linear loss of signal in specimens of thickness greater than ∼1.5 µm. We also show that the limitations of each approach can be ameliorated by combining 3D and 2D measurements using a stereological approach. Copyright © 2018. Published by Elsevier Inc.

Birefringence measurement of retinal nerve fiber layer using polarization-sensitive spectral domain optical coherence tomography with Jones matrix based analysis

NASA Astrophysics Data System (ADS)

Yamanari, Masahiro; Miura, Masahiro; Makita, Shuichi; Yatagai, Toyohiko; Yasuno, Yoshiaki

2007-02-01

Birefringence of retinal nerve fiber layer is measured by polarization-sensitive spectral domain optical coherence tomography using the B-scan-oriented polarization modulation method. Birefringence of the optical fiber and the cornea is compensated by Jones matrix based analysis. Three-dimensional phase retardation map around the optic nerve head and en-face phase retardation map of the retinal nerve fiber layer are shown. Unlike scanning laser polarimetry, our system can measure the phase retardation quantitatively without using bow-tie pattern of the birefringence in the macular region, which enables diagnosis of glaucoma even if the patients have macular disease.

Micromotor endoscope catheter for in vivo, ultrahigh-resolution optical coherence tomography

NASA Astrophysics Data System (ADS)

Herz, P. R.; Chen, Y.; Aguirre, A. D.; Schneider, K.; Hsiung, P.; Fujimoto, J. G.; Madden, K.; Schmitt, J.; Goodnow, J.; Petersen, C.

2004-10-01

A distally actuated, rotational-scanning micromotor endoscope catheter probe is demonstrated for ultrahigh-resolution in vivo endoscopic optical coherence tomography (OCT) imaging. The probe permits focus adjustment for visualization of tissue morphology at varying depths with improved transverse resolution compared with standard OCT imaging probes. The distal actuation avoids nonuniform scanning motion artifacts that are present with other probe designs and can permit a wider range of imaging speeds. Ultrahigh-resolution endoscopic imaging is demonstrated in a rabbit with <4-µm axial resolution by use of a femtosecond Crforsterite laser light source. The micromotor endoscope catheter probe promises to improve OCT imaging performance in future endoscopic imaging applications.

Correlating Atom Probe Tomography with Atomic-Resolved Scanning Transmission Electron Microscopy: Example of Segregation at Silicon Grain Boundaries.

PubMed

Stoffers, Andreas; Barthel, Juri; Liebscher, Christian H; Gault, Baptiste; Cojocaru-Mirédin, Oana; Scheu, Christina; Raabe, Dierk

2017-04-01

In the course of a thorough investigation of the performance-structure-chemistry interdependency at silicon grain boundaries, we successfully developed a method to systematically correlate aberration-corrected scanning transmission electron microscopy and atom probe tomography. The correlative approach is conducted on individual APT and TEM specimens, with the option to perform both investigations on the same specimen in the future. In the present case of a Σ9 grain boundary, joint mapping of the atomistic details of the grain boundary topology, in conjunction with chemical decoration, enables a deeper understanding of the segregation of impurities observed at such grain boundaries.

Spectroscopic optical coherence tomography based on wavelength de-multiplexing and smart pixel array detection

NASA Astrophysics Data System (ADS)

Laubscher, Markus; Bourquin, Stéphane; Froehly, Luc; Karamata, Boris; Lasser, Theo

2004-07-01

Current spectroscopic optical coherence tomography (OCT) methods rely on a posteriori numerical calculation. We present an experimental alternative for accessing spectroscopic information in OCT without post-processing based on wavelength de-multiplexing and parallel detection using a diffraction grating and a smart pixel detector array. Both a conventional A-scan with high axial resolution and the spectrally resolved measurement are acquired simultaneously. A proof-of-principle demonstration is given on a dynamically changing absorbing sample. The method's potential for fast spectroscopic OCT imaging is discussed. The spectral measurements obtained with this approach are insensitive to scan non-linearities or sample movements.

Use of multidetector-row computed tomography scan to detect pannus formation in prosthetic mechanical aortic valves

PubMed Central

Aladmawi, Mohamed A.; Vriz, Olga; Galzerano, Domenico

2017-01-01

Obstruction of a mechanical aortic valve by pannus formation at the subvalvular level is a major long-term complication of aortic valve replacement (AVR). In fact, pannus is sometime difficult to differentiate from patient-prosthesis mismatch or valve thrombosis. In most cases cine-angiography and echocardiography, either transthoracic or transesophageal, cannot correctly visualize the complication when the leaflets show a normal mobility. Recent technological refinements made this difficult diagnosis possible by ECG-gated computed tomography (CT) scan which shows adequate images in 90% of the cases and can differentiate pannus from fresh and organized thrombus. PMID:28540078

PENETRATING OCULAR INJURY WITH RETAINED INTRAOCULAR FOREIGN BODY FROM DRYWALL.

PubMed

Syed, Reema; Kim, Sung-Hye; Palacio, Agustina; Nunery, William R; Schaal, Shlomit

2018-03-23

To present a case of open globe injury and retained intraocular foreign body secondary to drywall. Interventional case report. A 21-year-old man presented with corneal laceration, iris defect, and vitreous hemorrhage after hammering drywall. Computed tomography scan was negative for intraocular foreign body, but a drywall intraretinal foreign body was found on 25-gauge vitrectomy. Intraoperative findings and 6-month follow-up are presented. Intraocular foreign body must always be suspected in all cases of penetrating ocular trauma. Although magnetic resonance imaging is ideal in diagnosing nonmetallic foreign bodies, computed tomography scan with Hounsfield units should be used in an emergency setting.

A Semi-Discrete Landweber-Kaczmarz Method for Cone Beam Tomography and Laminography Exploiting Geometric Prior Information

NASA Astrophysics Data System (ADS)

Vogelgesang, Jonas; Schorr, Christian

2016-12-01

We present a semi-discrete Landweber-Kaczmarz method for solving linear ill-posed problems and its application to Cone Beam tomography and laminography. Using a basis function-type discretization in the image domain, we derive a semi-discrete model of the underlying scanning system. Based on this model, the proposed method provides an approximate solution of the reconstruction problem, i.e. reconstructing the density function of a given object from its projections, in suitable subspaces equipped with basis function-dependent weights. This approach intuitively allows the incorporation of additional information about the inspected object leading to a more accurate model of the X-rays through the object. Also, physical conditions of the scanning geometry, like flat detectors in computerized tomography as used in non-destructive testing applications as well as non-regular scanning curves e.g. appearing in computed laminography (CL) applications, are directly taken into account during the modeling process. Finally, numerical experiments of a typical CL application in three dimensions are provided to verify the proposed method. The introduction of geometric prior information leads to a significantly increased image quality and superior reconstructions compared to standard iterative methods.

Scatter Reduction In Conventional Radiographic Tomography Using Rotating Apertures

NASA Astrophysics Data System (ADS)

Rudin, Stephen; Bednarek, Daniel R.

1981-08-01

Since images in conventional radiographic tomography are in-herently low in subject contrast, it is essential that scattered radiation be prevented from reaching the image receptor. Scanning beam or slit radiographic techniques are known to be the most efficient scatter elimination methods, yet have been inapplicable to this area of radiography. In this work it is shown that the scanning beam method using rotating aperture wheel (RAW) devices can be used in conventional tomography. One coder wheel between the x-ray tube and patient and two scatter discriminator wheels between the patient and image recep-tor form sections of the RAW "projection cone" with the lines of radia-tion from the x-ray source forming the "flux pyramid." As long as the projection cone follows the motion of the x-ray flux pyramid (with the ratios of the distances between the x-ray source, RAWs, patient, and image receptor kept constant throughout the motion) any RAW pattern may be used. Simple relations are given which describe the geometric constraints for various tomographic motions. As in any application of scanning slit techniques, it is possible to use the excellent scatter elimination capabilities of a RAW device either to improve image contrast or to reduce patient dose.

Simultaneous multimodal ophthalmic imaging using swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography

PubMed Central

Malone, Joseph D.; El-Haddad, Mohamed T.; Bozic, Ivan; Tye, Logan A.; Majeau, Lucas; Godbout, Nicolas; Rollins, Andrew M.; Boudoux, Caroline; Joos, Karen M.; Patel, Shriji N.; Tao, Yuankai K.

2016-01-01

Scanning laser ophthalmoscopy (SLO) benefits diagnostic imaging and therapeutic guidance by allowing for high-speed en face imaging of retinal structures. When combined with optical coherence tomography (OCT), SLO enables real-time aiming and retinal tracking and provides complementary information for post-acquisition volumetric co-registration, bulk motion compensation, and averaging. However, multimodality SLO-OCT systems generally require dedicated light sources, scanners, relay optics, detectors, and additional digitization and synchronization electronics, which increase system complexity. Here, we present a multimodal ophthalmic imaging system using swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography (SS-SESLO-OCT) for in vivo human retinal imaging. SESLO reduces the complexity of en face imaging systems by multiplexing spatial positions as a function of wavelength. SESLO image quality benefited from single-mode illumination and multimode collection through a prototype double-clad fiber coupler, which optimized scattered light throughput and reduce speckle contrast while maintaining lateral resolution. Using a shared 1060 nm swept-source, shared scanner and imaging optics, and a shared dual-channel high-speed digitizer, we acquired inherently co-registered en face retinal images and OCT cross-sections simultaneously at 200 frames-per-second. PMID:28101411

Sarcoidosis Occurring After Lymphoma

PubMed Central

London, Jonathan; Grados, Aurélie; Fermé, Christophe; Charmillon, Alexandre; Maurier, François; Deau, Bénédicte; Crickx, Etienne; Brice, Pauline; Chapelon-Abric, Catherine; Haioun, Corinne; Burroni, Barbara; Alifano, Marco; Le Jeunne, Claire; Guillevin, Loïc; Costedoat-Chalumeau, Nathalie; Schleinitz, Nicolas; Mouthon, Luc; Terrier, Benjamin

2014-01-01

Abstract Sarcoidosis is a granulomatous disease that most frequently affects the lungs with pulmonary infiltrates and/or bilateral hilar and mediastinal lymphadenopathy. An association of sarcoidosis and lymphoproliferative disease has previously been reported as the sarcoidosis-lymphoma syndrome. Although this syndrome is characterized by sarcoidosis preceding lymphoma, very few cases of sarcoidosis following lymphoma have been reported. We describe the clinical, biological, and radiological characteristics and outcome of 39 patients presenting with sarcoidosis following lymphoproliferative disease, including 14 previously unreported cases and 25 additional patients, after performing a literature review. Hodgkin lymphoma and non-Hodgkin lymphoma were equally represented. The median delay between lymphoma and sarcoidosis was 18 months. Only 16 patients (41%) required treatment. Sarcoidosis was of mild intensity or self-healing in most cases, and overall clinical response to sarcoidosis was excellent with complete clinical response in 91% of patients. Sarcoidosis was identified after a follow-up computerized tomography scan (CT-scan) or 18fluorodeoxyglucose-positron emission tomography/computerized tomography (18FDG-PET/CT) evaluation in 18/34 patients (53%). Sarcoidosis is therefore a differential diagnosis to consider when lymphoma relapse is suspected on a CT-scan or 18FDG-PET/CT, emphasizing the necessity to rely on histological confirmation of lymphoma relapse. PMID:25380084

Estimation of regional gas and tissue volumes of the lung in supine man using computed tomography.

PubMed

Denison, D M; Morgan, M D; Millar, A B

1986-08-01

This study was intended to discover how well computed tomography could recover the volume and weight of lung like foams in a body like shell, and then how well it could recover the volume and weight of the lungs in supine man. Model thoraces were made with various loaves of bread submerged in water. Computed tomography scans recovered the volume of the model lungs (true volume range 250-12,500 ml) within +0.2 (SD 68) ml and their weights (true range 72-3125 g) within +30 (78) g. Scans also recovered successive injections of 50 ml of water, within +/- 5 ml. Scans in 12 healthy supine men recovered their vital capacities, total lung capacities (TLC), and predicted tissue volumes with comparable accuracy. At total lung capacity the mean tissue volume of single lungs was 431 (64) ml and at residual volume (RV) it was 427 (63) ml. Tissue volume was then used to match inspiratory and expiratory slices and calculate regional ventilation. Throughout the mid 90% of lung the RV/TLC ratio was fairly constant--mean 21% (5%). New methods of presenting such regional data graphically and automatically are also described.

Impaired Neurobehavioural Performance in Untreated Obstructive Sleep Apnea Patients Using a Novel Standardised Test Battery.

PubMed

D'Rozario, Angela L; Field, Clarice J; Hoyos, Camilla M; Naismith, Sharon L; Dungan, George C; Wong, Keith K H; Grunstein, Ronald R; Bartlett, Delwyn J

2018-01-01

Although polysomnography (PSG) is the gold-standard measure for assessing disease severity in obstructive sleep apnea (OSA), it has limited value in identifying individuals experiencing significant neurobehavioural dysfunction. This study used a brief and novel computerised test battery to examine neurobehavioural function in adults with and without OSA. 204 patients with untreated OSA [age 49.3 (12.5) years; body mass index, [BMI] 33.6 (8.0) kg/m 2 ; Epworth sleepiness scale 12 (4.9)/24; apnea hypopnea index 33.6 (25.8)/h] and 50 non-OSA participants [age 39.2 (14.0) years; BMI 25.8 (4.2) kg/m 2 , ESS 3.6 (2.3)/24]. All participants completed a computerised neurobehavioural battery during the daytime in the sleep clinic. The OSA group subsequently underwent an overnight PSG. The 30 min test battery assessed cognitive domains of visual spatial scanning and selective attention (Letter Cancellation Test), executive function (Stroop task) and working memory (2- and 3-Back tasks), and a validated sustained attention task (psychomotor vigilance task, PVT). Group differences in performance were compared. Associations between disease severity and performance were examined in the OSA group. After controlling for age, gender and education, OSA patients demonstrated impaired performance on the Stroop-Text, 2 and 3-Back tasks, and the PVT compared with the non-OSA group. OSA patients had worse performance on the LCT with fewer average hits albeit with better accuracy. Some OSA polysomnographic disease severity measures were weakly correlated with performance. This brief test battery may provide a sensitive, standardised method of assessing daytime dysfunction in OSA.

Reduction in chemotherapy order errors with computerised physician order entry and clinical decision support systems.

PubMed

Aziz, Muhammad Tahir; Ur-Rehman, Tofeeq; Qureshi, Sadia; Bukhari, Nadeem Irfan

Medication errors in chemotherapy are frequent and lead to patient morbidity and mortality, as well as increased rates of re-admission and length of stay, and considerable extra costs. Objective: This study investigated the proposition that computerised chemotherapy ordering reduces the incidence and severity of chemotherapy protocol errors. A computerised physician order entry of chemotherapy order (C-CO) with clinical decision support system was developed in-house, including standardised chemotherapy protocol definitions, automation of pharmacy distribution, clinical checks, labeling and invoicing. A prospective study was then conducted in a C-CO versus paper based chemotherapy order (P-CO) in a 30-bed chemotherapy bay of a tertiary hospital. Both C-CO and P-CO orders, including pharmacoeconomic analysis and the severity of medication errors, were checked and validated by a clinical pharmacist. A group analysis and field trial were also conducted to assess clarity, feasibility and decision making. The C-CO was very usable in terms of its clarity and feasibility. The incidence of medication errors was significantly lower in the C-CO compared with the P-CO (10/3765 [0.26%] versus 134/5514 [2.4%]). There was also a reduction in dispensing time of chemotherapy protocols in the C-CO. The chemotherapy computerisation with clinical decision support system resulted in a significant decrease in the occurrence and severity of medication errors, improvements in chemotherapy dispensing and administration times, and reduction of chemotherapy cost.

Image reconstruction of x-ray tomography by using image J platform

NASA Astrophysics Data System (ADS)

Zain, R. M.; Razali, A. M.; Salleh, K. A. M.; Yahya, R.

2017-01-01

A tomogram is a technical term for a CT image. It is also called a slice because it corresponds to what the object being scanned would look like if it were sliced open along a plane. A CT slice corresponds to a certain thickness of the object being scanned. So, while a typical digital image is composed of pixels, a CT slice image is composed of voxels (volume elements). In the case of x-ray tomography, similar to x-ray Radiography, the quantity being imaged is the distribution of the attenuation coefficient μ(x) within the object of interest. The different is only on the technique to produce the tomogram. The image of x-ray radiography can be produced straight foward after exposed to x-ray, while the image of tomography produces by combination of radiography images in every angle of projection. A number of image reconstruction methods by converting x-ray attenuation data into a tomography image have been produced by researchers. In this work, Ramp filter in "filtered back projection" has been applied. The linear data acquired at each angular orientation are convolved with a specially designed filter and then back projected across a pixel field at the same angle. This paper describe the step of using Image J software to produce image reconstruction of x-ray tomography.

Computerised decision support in physical activity interventions: A systematic literature review.

PubMed

Triantafyllidis, Andreas; Filos, Dimitris; Claes, Jomme; Buys, Roselien; Cornelissen, Véronique; Kouidi, Evangelia; Chouvarda, Ioanna; Maglaveras, Nicos

2018-03-01

The benefits of regular physical activity for health and quality of life are unarguable. New information, sensing and communication technologies have the potential to play a critical role in computerised decision support and coaching for physical activity. We provide a literature review of recent research in the development of physical activity interventions employing computerised decision support, their feasibility and effectiveness in healthy and diseased individuals, and map out challenges and future research directions. We searched the bibliographic databases of PubMed and Scopus to identify physical activity interventions with computerised decision support utilised in a real-life context. Studies were synthesized according to the target user group, the technological format (e.g., web-based or mobile-based) and decision-support features of the intervention, the theoretical model for decision support in health behaviour change, the study design, the primary outcome, the number of participants and their engagement with the intervention, as well as the total follow-up duration. From the 24 studies included in the review, the highest percentage (n = 7, 29%) targeted sedentary healthy individuals followed by patients with prediabetes/diabetes (n = 4, 17%) or overweight individuals (n = 4, 17%). Most randomized controlled trials reported significantly positive effects of the interventions, i.e., increase in physical activity (n = 7, 100%) for 7 studies assessing physical activity measures, weight loss (n = 3, 75%) for 4 studies assessing diet, and reductions in glycosylated hemoglobin (n = 2, 66%) for 3 studies assessing glycose concentration. Accelerometers/pedometers were used in almost half of the studies (n = 11, 46%). Most adopted decision support features included personalised goal-setting (n = 16, 67%) and motivational feedback sent to the users (n = 15, 63%). Fewer adopted features were integration with electronic health records (n = 3, 13%) and alerts sent to caregivers (n = 4, 17%). Theoretical models of decision support in health behaviour to drive the development of the intervention were not reported in most studies (n = 14, 58%). Interventions employing computerised decision support have the potential to promote physical activity and result in health benefits for both diseased and healthy individuals, and help healthcare providers to monitor patients more closely. Objectively measured activity through sensing devices, integration with clinical systems used by healthcare providers and theoretical frameworks for health behaviour change need to be employed in a larger scale in future studies in order to realise the development of evidence-based computerised systems for physical activity monitoring and coaching. Copyright © 2017 Elsevier B.V. All rights reserved.

Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images

PubMed Central

Kim, Jooseong

2016-01-01

Objective The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis. PMID:26877978

High resolution multiplexed functional imaging in live embryos (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xu, Dongli; Zhou, Weibin; Peng, Leilei

2017-02-01

Fourier multiplexed fluorescence lifetime imaging (FmFLIM) scanning laser optical tomography (FmFLIM-SLOT) combines FmFLIM and Scanning laser optical tomography (SLOT) to perform multiplexed 3D FLIM imaging of live embryos. The system had demonstrate multiplexed functional imaging of zebrafish embryos genetically express Foster Resonant Energy Transfer (FRET) sensors. However, previous system has a 20 micron resolution because the focused Gaussian beam diverges quickly from the focused plane, makes it difficult to achieve high resolution imaging over a long projection depth. Here, we present a high-resolution FmFLIM-SLOT system with achromatic Bessel beam, which achieves 3 micron resolution in 3D deep tissue imaging. In Bessel-FmFLIM-SLOT, multiple laser excitation lines are firstly intensity modulated by a Michelson interferometer with a spinning polygon mirror optical delay line, which enables Fourier multiplexed multi-channel lifetime measurements. Then, a spatial light modulator and a prism are used to transform the modulated Gaussian laser beam to an achromatic Bessel beam. The achromatic Bessel beam scans across the whole specimen with equal angular intervals as sample rotated. After tomography reconstruction and the frequency domain lifetime analysis method, both the 3D intensity and lifetime image of multiple excitation-emission can be obtained. Using Bessel-FmFLIM-SLOT system, we performed cellular-resolution FLIM tomography imaging of live zebrafish embryo. Genetically expressed FRET sensors in these embryo will allow non-invasive observation of multiple biochemical processes in vivo.

Optimization and evaluation of metal injection molding by using X-ray tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Shidi; Zhang, Ruijie; Qu, Xuanhui, E-mail: quxh@ustb.edu.cn

2015-06-15

6061 aluminum alloy and 316L stainless steel green bodies were obtained by using different injection parameters (injection pressure, speed and temperature). After injection process, the green bodies were scanned by X-ray tomography. The projection and reconstruction images show the different kinds of defects obtained by the improper injection parameters. Then, 3D rendering of the Al alloy green bodies was used to demonstrate the spatial morphology characteristics of the serious defects. Based on the scanned and calculated results, it is convenient to obtain the proper injection parameters for the Al alloy. Then, reasons of the defect formation were discussed. During moldmore » filling, the serious defects mainly formed in the case of low injection temperature and high injection speed. According to the gray value distribution of projection image, a threshold gray value was obtained to evaluate whether the quality of green body can meet the desired standard. The proper injection parameters of 316L stainless steel can be obtained efficiently by using the method of analyzing the Al alloy injection. - Highlights: • Different types of defects in green bodies were scanned by using X-ray tomography. • Reasons of the defect formation were discussed. • Optimization of the injection parameters can be simplified greatly by the way of X-ray tomography. • Evaluation standard of the injection process can be obtained by using the gray value distribution of projection image.« less

Thermoluminescence dosimetry properties of new Cu doped CaF(2) nanoparticles.

PubMed

Zahedifar, M; Sadeghi, E

2013-12-01

Nanoparticles of Cu-doped calcium fluoride were synthesised by using the hydrothermal method. The structure of the prepared nanomaterial was characterised by the X-ray diffraction (XRD) pattern and energy dispersive spectrometer. The particle size of 36 nm was calculated from the XRD data. Its shape and size were also observed by scanning electron microscope. Thermoluminescence (TL) and photoluminescence of the produced phosphor were also considered. The computerised glow curve deconvolution procedure was used to identify the number of glow peaks included in the TL glow curve of the CaF2:Cu nanoparticles. The TL glow curve contains two overlapping glow peaks at ∼413 and 451 K. The TL response of this phosphor was studied for different Cu concentrations and the maximum sensitivity was found at 1 mol% of Cu impurity. Other dosimetric characteristics of the synthesised nanophosphor are also presented and discussed.

Abernethy malformation with portal vein aneurysm in a child

PubMed Central

Chandrashekhara, Sheragaru H.; Bhalla, Ashu Seith; Gupta, Arun Kumar; Vikash, C. S.; Kabra, Susheel Kumar

2011-01-01

Abernethy malformation is an extremely rare anomaly of the splanchnic venous system. We describe multidetector computed tomography findings of an incidentally detected Abernethy malformation with portal vein aneurysm in a two-and-half-year old child. The computed tomography scan was performed for the evaluation of respiratory distress, poor growth, and loss of appetite. PMID:21430844

An Integrated Teaching Method of Gross Anatomy and Computed Tomography Radiology

ERIC Educational Resources Information Center

Murakami, Tohru; Tajika, Yuki; Ueno, Hitoshi; Awata, Sachiko; Hirasawa, Satoshi; Sugimoto, Maki; Kominato, Yoshihiko; Tsushima, Yoshito; Endo, Keigo; Yorifuji, Hiroshi

2014-01-01

It is essential for medical students to learn and comprehend human anatomy in three dimensions (3D). With this in mind, a new system was designed in order to integrate anatomical dissections with diagnostic computed tomography (CT) radiology. Cadavers were scanned by CT scanners, and students then consulted the postmortem CT images during cadaver…

Are CT Scans Safe? Is It True That CT Scans May Increase My Risk of Cancer?

MedlinePlus

... products: Computed tomography (CT). U.S. Food and Drug Administration. http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115317.htm. Accessed Jan. 19, 2018. Lee C, et al. Radiation-related risks of ...

Application of computerised penile arterial waveform analysis in the diagnosis of arteriogenic impotence. An initial study in potent and impotent men.

PubMed

Desai, K M; Gingell, J C; Skidmore, R; Follett, D H

1987-11-01

A new method is described for evaluating arteriogenic impotence by means of noninvasive quantification of penile Doppler arterial waveforms using computerised analysis based on the Laplace Transform model. The haemodynamic changes occurring during a papaverine-induced erection in healthy potent volunteers have been recorded by this technique, which has also been shown to be capable of discriminating between a normal and an abnormal penile arterial supply in an initial study of potent and impotent men.

Miscellaneous indications in bone scintigraphy: metabolic bone diseases and malignant bone tumors.

PubMed

Cook, Gary J R; Gnanasegaran, Gopinath; Chua, Sue

2010-01-01

The diphosphonate bone scan is ideally suited to assess many global, focal or multifocal metabolic bone disorders and there remains a role for conventional bone scintigraphy in metabolic bone disorders at diagnosis, investigation of complications, and treatment response assessment. In contrast, the role of bone scintigraphy in the evaluation of primary malignant bone tumors has reduced with the improvement of morphologic imaging, such as computed tomography and magnetic resonance imaging. However, an increasing role for (18)F-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography is emerging as a functional assessment at diagnosis, staging, and neoadjuvant treatment response assessment.

Dual scan CT image recovery from truncated projections

NASA Astrophysics Data System (ADS)

Sarkar, Shubhabrata; Wahi, Pankaj; Munshi, Prabhat

2017-12-01

There are computerized tomography (CT) scanners available commercially for imaging small objects and they are often categorized as mini-CT X-ray machines. One major limitation of these machines is their inability to scan large objects with good image quality because of the truncation of projection data. An algorithm is proposed in this work which enables such machines to scan large objects while maintaining the quality of the recovered image.

Recent Advances in X-ray Cone-beam Computed Laminography.

PubMed

O'Brien, Neil S; Boardman, Richard P; Sinclair, Ian; Blumensath, Thomas

2016-10-06

X-ray computed tomography is an established volume imaging technique used routinely in medical diagnosis, industrial non-destructive testing, and a wide range of scientific fields. Traditionally, computed tomography uses scanning geometries with a single axis of rotation together with reconstruction algorithms specifically designed for this setup. Recently there has however been increasing interest in more complex scanning geometries. These include so called X-ray computed laminography systems capable of imaging specimens with large lateral dimensions or large aspect ratios, neither of which are well suited to conventional CT scanning procedures. Developments throughout this field have thus been rapid, including the introduction of novel system trajectories, the application and refinement of various reconstruction methods, and the use of recently developed computational hardware and software techniques to accelerate reconstruction times. Here we examine the advances made in the last several years and consider their impact on the state of the art.

Strategies to improve phase-stability of ultrafast swept source optical coherence tomography for single shot imaging of transient mechanical waves at 16 kHz frame rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Shaozhen; Wei, Wei; Hsieh, Bao-Yu

We present single-shot phase-sensitive imaging of propagating mechanical waves within tissue, enabled by an ultrafast optical coherence tomography (OCT) system powered by a 1.628 MHz Fourier domain mode-locked (FDML) swept laser source. We propose a practical strategy for phase-sensitive measurement by comparing the phases between adjacent OCT B-scans, where the B-scan contains a number of A-scans equaling an integer number of FDML buffers. With this approach, we show that micro-strain fields can be mapped with ∼3.0 nm sensitivity at ∼16 000 fps. The system's capabilities are demonstrated on porcine cornea by imaging mechanical wave propagation launched by a pulsed UV laser beam, promisingmore » non-contact, real-time, and high-resolution optical coherence elastography.« less

Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

PubMed Central

Shirazi, Muhammad Faizan; Park, Kibeom; Wijesinghe, Ruchire Eranga; Jeong, Hyosang; Han, Sangyeob; Kim, Pilun; Jeon, Mansik; Kim, Jeehyun

2016-01-01

An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products. PMID:27690043

Cardiovascular Computed Tomography Phantom Fabrication and Characterization through the Tailored Properties of Polymeric Composites and Cellular Foams

NASA Astrophysics Data System (ADS)

Hoy, Carlton F. O.

The overall objective of this thesis was to control the fabrication technique and relevant material properties for phantom devices designated for computed tomography (CT) scanning. Fabrication techniques using polymeric composites and foams were detailed together with parametric studies outlining the fundamentals behind the changes in material properties which affect the characteristic CT number. The composites fabricated used polyvinylidene fluoride (PVDF), thermoplastic polyurethane (TPU) and polyethylene (PE) with hydroxylapatite (hA) as additive with different composites made by means of different weight percentages of additive. Polymeric foams were fabricated through a batch foaming technique with the heating time controlled to create different levels of foams. Finally, the effect of fabricated phantoms under varied scanning media was assessed to determine whether self-made phantoms can be scanned accurately under non-water or rigid environments allowing for the future development of complex shaped or fragile material types.

Positron emission tomography suggests that the rate of progression of idiopathic parkinsonism is slow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatt, M.H.; Snow, B.J.; Martin, W.R.

1991-06-01

The authors performed sequential positron emission tomography scans with 6-(18F)fluoro-L-dopa in 9 patients with idiopathic parkinsonism and 7 age-matched normal control subjects to compare changes in the nigrostriatal dopaminergic pathway over time. The mean interval between the scans was 3.3 years for the group with idiopathic parkinsonism and 3.9 years for the control subjects. The scans were analyzed by calculating the ratio of striatal to background radioactivity. Both groups showed statistically significant reductions of striatal uptake over the interval. The rate of decrease was almost identical in each group (p = 0.6). They infer that the usual rate of lossmore » of integrity of the dopaminergic nigrostriatal pathway in patients with idiopathic parkinsonism is slow and the rate of change between the two groups was comparable.« less

Multi-Mounted X-Ray Computed Tomography.

PubMed

Fu, Jian; Liu, Zhenzhong; Wang, Jingzheng

2016-01-01

Most existing X-ray computed tomography (CT) techniques work in single-mounted mode and need to scan the inspected objects one by one. It is time-consuming and not acceptable for the inspection in a large scale. In this paper, we report a multi-mounted CT method and its first engineering implementation. It consists of a multi-mounted scanning geometry and the corresponding algebraic iterative reconstruction algorithm. This approach permits the CT rotation scanning of multiple objects simultaneously without the increase of penetration thickness and the signal crosstalk. Compared with the conventional single-mounted methods, it has the potential to improve the imaging efficiency and suppress the artifacts from the beam hardening and the scatter. This work comprises a numerical study of the method and its experimental verification using a dataset measured with a developed multi-mounted X-ray CT prototype system. We believe that this technique is of particular interest for pushing the engineering applications of X-ray CT.

Optimization of coronary attenuation in coronary computed tomography angiography using diluted contrast material.

PubMed

Kawaguchi, Naoto; Kurata, Akira; Kido, Teruhito; Nishiyama, Yoshiko; Kido, Tomoyuki; Miyagawa, Masao; Ogimoto, Akiyoshi; Mochizuki, Teruhito

2014-01-01

The purpose of this study was to evaluate a personalized protocol with diluted contrast material (CM) for coronary computed tomography angiography (CTA). One hundred patients with suspected coronary artery disease underwent retrospective electrocardiogram-gated coronary CTA on a 256-slice multidetector-row CT scanner. In the diluted CM protocol (n=50), the optimal scan timing and CM dilution rate were determined by the timing bolus scan, with 20% CM dilution (5ml/s during 10s) being considered suitable to achieve the target arterial attenuation of 350 Hounsfield units (HU). In the body weight (BW)-adjusted protocol (n=50, 222mg iodine/kg), only the optimal scan timing was determined by the timing bolus scan. The injection rate and volume in the timing bolus scan and real scan were identical between the 2 protocols. We compared the means and variations in coronary attenuation between the 2 protocols. Coronary attenuation (mean±SD) in the diluted CM and BW-adjusted protocols was 346.1±23.9 HU and 298.8±45.2 HU, respectively. The diluted CM protocol provided significantly higher coronary attenuation and lower variance than did the BW-adjusted protocol (P<0.05, in each). The diluted CM protocol facilitates more uniform attenuation on coronary CTA in comparison with the BW-adjusted protocol.  

Automatic and manual segmentation of healthy retinas using high-definition optical coherence tomography.

PubMed

Golbaz, Isabelle; Ahlers, Christian; Goesseringer, Nina; Stock, Geraldine; Geitzenauer, Wolfgang; Prünte, Christian; Schmidt-Erfurth, Ursula Margarethe

2011-03-01

This study compared automatic- and manual segmentation modalities in the retina of healthy eyes using high-definition optical coherence tomography (HD-OCT). Twenty retinas in 20 healthy individuals were examined using an HD-OCT system (Carl Zeiss Meditec, Inc.). Three-dimensional imaging was performed with an axial resolution of 6 μm at a maximum scanning speed of 25,000 A-scans/second. Volumes of 6 × 6 × 2 mm were scanned. Scans were analysed using a matlab-based algorithm and a manual segmentation software system (3D-Doctor). The volume values calculated by the two methods were compared. Statistical analysis revealed a high correlation between automatic and manual modes of segmentation. The automatic mode of measuring retinal volume and the corresponding three-dimensional images provided similar results to the manual segmentation procedure. Both methods were able to visualize retinal and subretinal features accurately. This study compared two methods of assessing retinal volume using HD-OCT scans in healthy retinas. Both methods were able to provide realistic volumetric data when applied to raster scan sets. Manual segmentation methods represent an adequate tool with which to control automated processes and to identify clinically relevant structures, whereas automatic procedures will be needed to obtain data in larger patient populations. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.

The research and development of the adaptive optics in ophthalmology

NASA Astrophysics Data System (ADS)

Wu, Chuhan; Zhang, Xiaofang; Chen, Weilin

2015-08-01

Recently the combination of adaptive optics and ophthalmology has made great progress and become highly effective. The retina disease is diagnosed by retina imaging technique based on scanning optical system, so the scanning of eye requires optical system characterized by great ability of anti-moving and optical aberration correction. The adaptive optics possesses high level of adaptability and is available for real time imaging, which meets the requirement of medical retina detection with accurate images. Now the Scanning Laser Ophthalmoscope and the Optical Coherence Tomography are widely used, which are the core techniques in the area of medical retina detection. Based on the above techniques, in China, a few adaptive optics systems used for eye medical scanning have been designed by some researchers from The Institute of Optics And Electronics of CAS(The Chinese Academy of Sciences); some foreign research institutions have adopted other methods to eliminate the interference of eye moving and optical aberration; there are many relevant patents at home and abroad. In this paper, the principles and relevant technique details of the Scanning Laser Ophthalmoscope and the Optical Coherence Tomography are described. And the recent development and progress of adaptive optics in the field of eye retina imaging are analyzed and summarized.

[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. Copyright © 2015 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

Optical Coherence Tomography Evaluation in the Multicenter Uveitis Steroid Treatment (MUST) Trial

PubMed Central

Domalpally, Amitha; Altaweel, Michael M.; Kempen, John H.; Myers, Dawn; Davis, Janet L; Foster, C Stephen; Latkany, Paul; Srivastava, Sunil K.; Stawell, Richard J.; Holbrook, Janet T.

2013-01-01

Purpose To describe the evaluation of optical coherence tomography (OCT) scans in the Muliticenter Uveitis Steroid Treatment (MUST) trial and report baseline OCT features of enrolled participants. Methods Time domain OCTs acquired by certified photographers using a standardized scan protocol were evaluated at a Reading Center. Accuracy of retinal thickness data was confirmed with quality evaluation and caliper measurement of centerpoint thickness (CPT) was performed when unreliable. Morphological evaluation included cysts, subretinal fluid,epiretinal membranes (ERMs),and vitreomacular traction. Results Of the 453 OCTs evaluated, automated retinal thickness was accurate in 69.5% of scans, caliper measurement was performed in 26%,and 4% were ungradable. Intraclass correlation was 0.98 for reproducibility of caliper measurement. Macular edema (centerpoint thickness ≥ 240um) was present in 36%. Cysts were present in 36.6% of scans and ERMs in 27.8%, predominantly central. Intergrader agreement ranged from 78 − 82% for morphological features. Conclusion Retinal thickness data can be retrieved in a majority of OCT scans in clinical trial submissions for uveitis studies. Small cysts and ERMs involving the center are common in intermediate and posterior/panuveitis requiring systemic corticosteroid therapy. PMID:23163490

Pretreatment with diphenoxylate hydrochloride/atropine sulfate (Lomotil) does not decrease physiologic bowel FDG activity on PET/CT scans of the abdomen and pelvis.

PubMed

Murphy, Robert; Doerger, Kirk M; Nathan, Mark A; Lowe, Val J

2009-01-01

Physiologic uptake of 2-[(18)F]-fluoro-2-deoxy-D: -glucose (FDG) by bowel can confound positron emission tomography/computed tomography (PET/CT) assessment for abdominal pathology, particularly within the bowel itself. We wished to determine if oral administration of the antimotility agent, Lomotil (5 mg diphenoxylate hydrochloride/0.05 mg atropine sulfate; G.D. Searle and Company, a division of Pfizer), prior to PET/CT scanning would reduce physiologic uptake of FDG by the small bowel and colon (lower gastrointestinal [GI] tract). Patients undergoing PET/CT scans for lymphoma were enrolled in a prospective, randomized, double-blinded study and received either 10 mL water (control group) or 10 mL Lomotil (experimental group) orally 30-60 min prior to scanning. Scans were reviewed independently by two blinded experienced readers and scored for the degree of FDG activity in the lower GI tract relative to liver activity. The administration of Lomotil prior to PET/CT scanning did not reduce physiologic FDG activity in the small bowel and colon. In contrast, increased radiotracer uptake by the lower GI tract was observed in the Lomotil group compared to the control group. Pretreatment with Lomotil prior to PET/CT scanning confers no benefit toward the reduction of physiologic FDG uptake by the small bowel and colon.

Translational-circular scanning for magneto-acoustic tomography with current injection.

PubMed

Wang, Shigang; Ma, Ren; Zhang, Shunqi; Yin, Tao; Liu, Zhipeng

2016-01-27

Magneto-acoustic tomography with current injection involves using electrical impedance imaging technology. To explore the potential applications in imaging biological tissue and enhance image quality, a new scan mode for the transducer is proposed that is based on translational and circular scanning to record acoustic signals from sources. An imaging algorithm to analyze these signals is developed in respect to this alternative scanning scheme. Numerical simulations and physical experiments were conducted to evaluate the effectiveness of this scheme. An experiment using a graphite sheet as a tissue-mimicking phantom medium was conducted to verify simulation results. A pulsed voltage signal was applied across the sample, and acoustic signals were recorded as the transducer performed stepped translational or circular scans. The imaging algorithm was used to obtain an acoustic-source image based on the signals. In simulations, the acoustic-source image is correlated with the conductivity at the sample boundaries of the sample, but image results change depending on distance and angular aspect of the transducer. In general, as angle and distance decreases, the image quality improves. Moreover, experimental data confirmed the correlation. The acoustic-source images resulting from the alternative scanning mode has yielded the outline of a phantom medium. This scan mode enables improvements to be made in the sensitivity of the detecting unit and a change to a transducer array that would improve the efficiency and accuracy of acoustic-source images.

Prevalence of upper airway obstruction in patients with apparently asymptomatic euthyroid multi nodular goitre

PubMed Central

Menon, Sunil K.; Jagtap, Varsha S.; Sarathi, Vijaya; Lila, Anurag R.; Bandgar, Tushar R.; Menon, Padmavathy S; Shah, Nalini S.

2011-01-01

Aims: To study the prevalence of upper airway obstruction (UAO) in “apparently asymptomatic” patients with euthyroid multinodular goitre (MNG) and find correlation between clinical features, UAO on pulmonary function test (PFT) and tracheal narrowing on computerised tomography (CT). Materials and Methods: Consecutive patients with apparently asymptomatic euthyroid MNG attending thyroid clinic in a tertiary centre underwent clinical examination to elicit features of UAO, PFT, and CT of neck and chest. Statistical Analysis Used: Statistical analysis was done with SPSS version 11.5 using paired t-test, Chi square test, and Fisher's exact test. P value of <0.05 was considered to be significant. Results: Fifty-six patients (52 females and four males) were studied. The prevalence of UAO (PFT) and significant tracheal narrowing (CT) was 14.3%. and 9.3%, respectively. Clinical features failed to predict UAO or significant tracheal narrowing. Tracheal narrowing (CT) did not correlate with UAO (PFT). Volume of goitre significantly correlated with degree of tracheal narrowing. Conclusions: Clinical features do not predict UAO on PFT or tracheal narrowing on CT in apparently asymptomatic patients with euthyroid MNG. PMID:21966649

Determinants of change in body weight and body fat distribution over 5.5 years in a sample of free-living black South African women

PubMed Central

Chantler, Sarah; Dickie, Kasha; Micklesfield, Lisa K; Goedecke, Julia H; Goedecke, Julia H; Micklesfield, Lisa K

2016-01-01

Summary Objective To identify socio-demographic and lifestyle determinants of weight gain in a sample of premenopasual black South African (SA) women. Methods Changes in body composition (dual-energy X-ray absorptiometry, computerised tomography), socio-economic status (SES) and behavioural/lifestyle factors were measured in 64 black SA women at baseline (27 ± 8 years) and after 5.5 years. Results A lower body mass index (BMI) and nulliparity, together with access to sanitation, were significant determinants of weight gain and change in body fat distribution over 5.5 years. In addition, younger women increased their body weight more than their older counterparts, but this association was not independent of other determinants. Conclusion Further research is required to examine the effect of changing SES, as well as the full impact of childbearing on weight gain over time in younger women with lower BMIs. This information will suggest areas for possible intervention to prevent long-term weight gain in these women. PMID:27224680

Oncological emergencies: clinical importance and principles of management.

PubMed

Samphao, S; Eremin, J M; Eremin, O

2010-11-01

Oncological emergencies are common conditions associated with significant morbidity and mortality. Delay in diagnosis and treatment can result in unfavourable outcomes. Cancer itself, cancer-related hormones or cytokines, or treatment effects can cause emergency problems. Febrile neutropaenia, frequently associated with chemotherapy, can lead to life-threatening conditions. Treatment requires systematic evaluation and early empirical antibiotics. Hypercalcaemia of malignancy is the most common metabolic emergency in cancer patients. Non-specific clinical features may cause delay in diagnosis and increase morbidity and mortality. Treatment includes active fluid resuscitation, diuretics and intravenous bisphosphonates. Superior vena cava syndrome is usually caused by external compression. Computerised tomography is useful to confirm diagnosis, evaluate the extent of disease and guide invasive tissue diagnosis. Treatment and prognosis depend on the underlying malignancies. Spinal cord compression is a true emergency due to risk of permanent neurological impairment. Localised back pain is the most common presenting symptom while late presentation of neurological deficit is associated with irreversible outcomes. Magnetic resonance imaging is the investigation of choice. Treatment includes corticosteroids, radiotherapy and/or decompressive surgery. © 2009 The Authors. European Journal of Cancer Care © 2009 Blackwell Publishing Ltd.

A 3D reconstruction algorithm for magneto-acoustic tomography with magnetic induction based on ultrasound transducer characteristics.

PubMed

Ma, Ren; Zhou, Xiaoqing; Zhang, Shunqi; Yin, Tao; Liu, Zhipeng

2016-12-21

In this study we present a three-dimensional (3D) reconstruction algorithm for magneto-acoustic tomography with magnetic induction (MAT-MI) based on the characteristics of the ultrasound transducer. The algorithm is investigated to solve the blur problem of the MAT-MI acoustic source image, which is caused by the ultrasound transducer and the scanning geometry. First, we established a transducer model matrix using measured data from the real transducer. With reference to the S-L model used in the computed tomography algorithm, a 3D phantom model of electrical conductivity is set up. Both sphere scanning and cylinder scanning geometries are adopted in the computer simulation. Then, using finite element analysis, the distribution of the eddy current and the acoustic source as well as the acoustic pressure can be obtained with the transducer model matrix. Next, using singular value decomposition, the inverse transducer model matrix together with the reconstruction algorithm are worked out. The acoustic source and the conductivity images are reconstructed using the proposed algorithm. Comparisons between an ideal point transducer and the realistic transducer are made to evaluate the algorithms. Finally, an experiment is performed using a graphite phantom. We found that images of the acoustic source reconstructed using the proposed algorithm are a better match than those using the previous one, the correlation coefficient of sphere scanning geometry is 98.49% and that of cylinder scanning geometry is 94.96%. Comparison between the ideal point transducer and the realistic transducer shows that the correlation coefficients are 90.2% in sphere scanning geometry and 86.35% in cylinder scanning geometry. The reconstruction of the graphite phantom experiment also shows a higher resolution using the proposed algorithm. We conclude that the proposed reconstruction algorithm, which considers the characteristics of the transducer, can obviously improve the resolution of the reconstructed image. This study can be applied to analyse the effect of the position of the transducer and the scanning geometry on imaging. It may provide a more precise method to reconstruct the conductivity distribution in MAT-MI.

Digital volume tomography in the diagnosis of peri-implant defects: an in vitro study on native pig mandibles.

PubMed

Mengel, Reiner; Kruse, Björn; Flores-de-Jacoby, Lavin

2006-07-01

The aim of this study of native pig mandibles was to investigate the accuracy and quality of the representation of peri-implant defects by intraoral radiography (IR), panoramic radiography (PR), computer tomography (CT), and digital volume tomography (DVT). The examination was carried out on 19 native pig mandibles. In the toothless sections of the mandibles, one or two implants were inserted. Following the standardized preparation of peri-implant defects (11 each of dehiscences, fenestrations, and 2- to 3-walled intrabony defects), IR, PR, CT, and DVT were performed. The peri-implant defects were measured using appropriate software on the digitized IR and PR image programs. As a control method, the peri-implant bone defects were measured directly using a reflecting stereomicroscope with measuring ocular. The statistical comparison between the measurements of the radiographic scans and those of the direct readings of the peri-implant defects was performed with Pearson's correlation coefficient. The quality of the radiographic scans was determined through the subjective perception and detectability of the peri-implant defects by five independent observers. In the DVT and CT scans, it was possible to measure all the bone defects in three planes. Comparison with the direct peri-implant defect measurements yielded a mean deviation of 0.17+/-0.11 mm for the DVT scans and 0.18+/-0.12 mm for the CT scans. On the IR and PR images, the defects could be detected only in the mesio-distal and cranio-caudal planes. In comparison with the direct measurements of the peri-implant defects, the IR images revealed a mean deviation of 0.34+/-0.30 mm, and the PR images revealed a mean deviation of 0.41+/-0.35 mm. The quality rating of the radiographic images was highest for the DVT scans. Overall, the CT and DVT scans displayed only a slight deviation in the extent of the peri-implant defects. Both radiographic imaging techniques permitted imaging of peri-implant defects in three planes, true to scale, and without overlay or distortion. The DVT scans showed the best imaging quality.

Simulation of computed tomography dose based on voxel phantom

NASA Astrophysics Data System (ADS)

Liu, Chunyu; Lv, Xiangbo; Li, Zhaojun

2017-01-01

Computed Tomography (CT) is one of the preferred and the most valuable imaging tool used in diagnostic radiology, which provides a high-quality cross-sectional image of the body. It still causes higher doses of radiation to patients comparing to the other radiological procedures. The Monte-Carlo method is appropriate for estimation of the radiation dose during the CT examinations. The simulation of the Computed Tomography Dose Index (CTDI) phantom was developed in this paper. Under a similar conditions used in physical measurements, dose profiles were calculated and compared against the measured values that were reported. The results demonstrate a good agreement between the calculated and the measured doses. From different CT exam simulations using the voxel phantom, the highest absorbed dose was recorded for the lung, the brain, the bone surface. A comparison between the different scan type shows that the effective dose for a chest scan is the highest one, whereas the effective dose values during abdomen and pelvis scan are very close, respectively. The lowest effective dose resulted from the head scan. Although, the dose in CT is related to various parameters, such as the tube current, exposure time, beam energy, slice thickness and patient size, this study demonstrates that the MC simulation is a useful tool to accurately estimate the dose delivered to any specific organs for patients undergoing the CT exams and can be also a valuable technique for the design and the optimization of the CT x-ray source.

Correction of absorption-edge artifacts in polychromatic X-ray tomography in a scanning electron microscope for 3D microelectronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laloum, D., E-mail: david.laloum@cea.fr; CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9; STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles

2015-01-15

X-ray tomography is widely used in materials science. However, X-ray scanners are often based on polychromatic radiation that creates artifacts such as dark streaks. We show this artifact is not always due to beam hardening. It may appear when scanning samples with high-Z elements inside a low-Z matrix because of the high-Z element absorption edge: X-rays whose energy is above this edge are strongly absorbed, violating the exponential decay assumption for reconstruction algorithms and generating dark streaks. A method is proposed to limit the absorption edge effect and is applied on a microelectronic case to suppress dark streaks between interconnections.

Micromotor endoscope catheter for in vivo, ultrahigh-resolution optical coherence tomography.

PubMed

Herz, P R; Chen, Y; Aguirre, A D; Schneider, K; Hsiung, P; Fujimoto, J G; Madden, K; Schmitt, J; Goodnow, J; Petersen, C

2004-10-01

A distally actuated, rotational-scanning micromotor endoscope catheter probe is demonstrated for ultrahigh-resolution in vivo endoscopic optical coherence tomography (OCT) imaging. The probe permits focus adjustment for visualization of tissue morphology at varying depths with improved transverse resolution compared with standard OCT imaging probes. The distal actuation avoids nonuniform scanning motion artifacts that are present with other probe designs and can permit a wider range of imaging speeds. Ultrahigh-resolution endoscopic imaging is demonstrated in a rabbit with <4-microm axial resolution by use of a femtosecond Cr:forsterite laser light source. The micromotor endoscope catheter probe promises to improve OCT imaging performance in future endoscopic imaging applications.

High frame-rate en face optical coherence tomography system using KTN optical beam deflector

NASA Astrophysics Data System (ADS)

Ohmi, Masato; Shinya, Yusuke; Imai, Tadayuki; Toyoda, Seiji; Kobayashi, Junya; Sakamoto, Tadashi

2017-02-01

We developed high frame-rate en face optical coherence tomography (OCT) system using KTa1-xNbxO3 (KTN) optical beam deflector. In the imaging system, the fast scanning was performed at 200 kHz by the KTN optical beam deflector, while the slow scanning was performed at 800 Hz by the galvanometer mirror. As a preliminary experiment, we succeeded in obtaining en face OCT images of human fingerprint with a frame rate of 800 fps. This is the highest frame-rate obtained using time-domain (TD) en face OCT imaging. The 3D-OCT image of sweat gland was also obtained by our imaging system.

Posterior reversible encephalopathy with late postpartum eclampsia and short-term memory loss: a case report.

PubMed

Gimovsky, Martin L; Guzman, Guillermo M; Koscica, Karen L; Nazir, Munir A; Ross, Diane E

2010-01-01

Late postpartum eclampsia is more frequently recognized than past reports indicate. This report describes the association of a reversible encephalopathy in a woman with late postpartum eclampsia. A woman with lupus nephritis presented 7 days postpartum with eclampsia. Postseizure findings included dramatic short-term memory loss. Although a computed tomography scan was negative, subsequent magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) demonstrated vascular changes associated with a reversible encephalopathy. Conservative treatment with analeptic and antihypertensive therapy allowed a rapid resolution of all symptomatology. In women with eclampsia and unusual neurologic findings, an MRI/MRA may be useful even in the presence of a negative computed tomography scan.

Development of novel high-speed en face optical coherence tomography system using KTN optical beam deflector

NASA Astrophysics Data System (ADS)

Ohmi, Masato; Fukuda, Akihiro; Miyazu, Jun; Ueno, Masahiro; Toyoda, Seiji; Kobayashi, Junya

2015-02-01

We developed a novel high-speed en face optical coherence tomography (OCT) system using a KTa1-xNbxO3 (KTN) optical beam deflector. Using the imaging system, fast scanning was performed at 200 kHz by the KTN beam deflector, while slow scanning was performed at 400 Hz by the galvanometer mirror. In a preliminary experiment, we obtained en face OCT images of a human fingerprint at 400 fps. This is the highest speed reported in time-domain en face OCT imaging and is comparable to the speed of swept-source OCT. A 3D-OCT image of a sweat gland was also obtained by our imaging system.

Dense concentric circle scanning protocol for measuring pulsatile retinal blood flow in rats with Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Tan, Bingyao; Hosseinaee, Zohreh; Bizheva, Kostadinka

2017-11-01

The variability in the spatial orientation of retinal blood vessels near the optic nerve head (ONH) results in imprecision of the measured Doppler angle and therefore the pulsatile blood flow (BF), when those parameters are evaluated using Doppler OCT imaging protocols based on dual-concentric circular scans. Here, we utilized a dense concentric circle scanning protocol and evaluated its precision for measuring pulsatile retinal BF in rats for different numbers of the circular scans. An spectral domain optical coherence tomography (SD-OCT) system operating in the 1060-nm spectral range with image acquisition rate of 47,000 A-scans/s was used to acquire concentric circular scans centered at the rat's ONH, with diameters ranging from 0.8 to 1.0 mm. A custom, automatic blood vessel segmentation algorithm was used to track the spatial orientation of the retinal blood vessels in three dimensions, evaluate the spatially dependent Doppler angle and calculate more accurately the axial BF for each major retinal blood vessel. Metrics such as retinal BF, pulsatility index, and resistance index were evaluated for each and all of the major retinal blood vessels. The performance of the proposed dense concentric circle scanning protocols was compared with that of the dual-circle scanning protocol. Results showed a 3.8±2.2 deg difference in the Doppler angle calculation between the two approaches, which resulted in ˜7% difference in the calculated retinal BF.

The design, construction and implementation of a computerised trauma registry in a developing South African metropolitan trauma service.

PubMed

Laing, G L; Bruce, J L; Aldous, C; Clarke, D L

2014-01-01

The Pietermaritzburg Metropolitan Trauma Service formerly lacked a robust computerised trauma registry. This made surgical audit difficult for the purpose of quality of care improvement and development. We aimed to design, construct and implement a computerised trauma registry within our service. Twelve months following its implementation, we sought to examine and report on the quality of the registry. Formal ethical approval to maintain a computerised trauma registry was obtained prior to undertaking any design and development. Appropriate commercial software was sourced to develop this project. The registry was designed as a flat file. A flat file is a plain text or mixed text and binary file which usually contains one record per line or physical record. Thereafter the registry file was launched onto a secure server. This provided the benefits of access security and automated backups. Registry training was provided to clients by the developer. The exercise of data capture was then integrated into the process of service delivery, taking place at the endpoint of patient care (discharge, transfer or death). Twelve months following its implementation, the compliance rates of data entry were measured. The developer of this project managed to design, construct and implement an electronic trauma registry into the service. Twelve months following its implementation the data were extracted and audited to assess the quality. A total of 2640 patient entries were captured onto the registry. Compliance rates were in the order of eighty percent and client satisfaction rates were high. A number of deficits were identified. These included the omission of weekend discharges and underreporting of deaths. The construction and implementation of the computerised trauma registry was the beginning of an endeavour to continue improvements in the quality of care within our service. The registry provided a reliable audit at twelve months post implementation. Deficits and limitations were identified and new strategies have been planned to overcome these problems and integrate the trauma registry into the process of clinical care. Copyright © 2013 Elsevier Ltd. All rights reserved.

Interchangeability and reliability of macular perfusion parameter measurements using optical coherence tomography angiography

PubMed Central

Dong, Jing; Jia, Ya-ding; Wu, Qiang; Zhang, Suhua; Jia, Yali; Huang, David; Wang, Xiaogang

2018-01-01

Aim The aim of the study was to investigate the interchangeability and reliability of macular perfusion measurements using optical coherence tomography angiography. Methods A prospective cross-sectional observational study. Healthy adult Chinese subjects were recruited. Macular perfusion parameters were automatically analysed by software included in a spectral-domain optical coherence tomography system. The vessel density (VD) of the whole, parafovea, superior-hemi, inferior-hemi, fovea, temporal, superior, nasal and inferior quadrants as well as the foveal avascular zone (FAZ) and choroidal capillary VD (CCVD) were quantified. Results A total of 51 eyes in 27 subjects were included (8 men and 19 women, mean age 24±4 years). Significant differences in VD of all quadrants (all p<0.001) was detected between the 3×3 mm and 6×6 mm macular scan size. The biggest difference of VD between the two scan size was 5.14±4.03, which was not clinically meaningful. No statistically significant differences were found in FAZ or CCVD between the two different scan sizes. The mean intraclass correlation coefficient (ICC) between two measurements from the inter-rater of 20 eyes was from 0.560 to 0.893 for VD and 0.845 for FAZ. The mean ICC between two measurements from the intrarater of 20 eyes was from 0.497 to 0.870 for VD and 0.780 for FAZ. Conclusions FAZ and CCVD are interchangeable between the 3×3 mm and 6×6 mm macular scan sizes. The VD differences between the two different scan sizes are not clinically meaningful. The macular perfusion parameters presented good but not perfect reliability, which should be acknowledged in clinical practice. PMID:28336674

Accuracy of CBCT for volumetric measurement of simulated periapical lesions.

PubMed

Ahlowalia, M S; Patel, S; Anwar, H M S; Cama, G; Austin, R S; Wilson, R; Mannocci, F

2013-06-01

To compare the accuracy of cone beam computed tomography (CBCT) and micro-computed tomography (μCT) when measuring the volume of bone cavities. Ten irregular-shaped cavities of varying dimensions were created in bovine bone specimens using a rotary diamond bur. The samples were then scanned using the Accuitomo 3D CBCT scanner. The scanned information was converted to the Digital Imaging and Communication in Medicine (DICOM) format ready for analysis. Once formatted, 10 trained and calibrated examiners segmented the scans and measured the volumes of the lesions. Intra/interexaminer agreement was assessed by each examiner re-segmenting each scan after a 2-week interval. Micro-CT scans were analysed by a single examiner. To achieve a physical reading of the artificially created cavities, replicas were created using dimensionally stable silicone impression material. After measuring the mass of each impression sample, the volume was calculated by dividing the mass of each sample by the density of the set impression material. Further corroboration of these measurements was obtained by employing Archimedes' principle to measure the volume of each impression sample. Intraclass correlation was used to assess agreement. Both CBCT (mean volume: 175.9 mm3) and μCT (mean volume: 163.1 mm3) showed a high degree of agreement (intraclass correlation coefficient >0.9) when compared to both weighed and 'Archimedes' principle' measurements (mean volume: 177.7 and 182.6 mm3, respectively). Cone beam computed tomography is an accurate means of measuring volume of artificially created bone cavities in an ex vivo model. This may provide a valuable tool for monitoring the healing rate of apical periodontitis; further investigations are warranted. © 2012 International Endodontic Journal. Published by Blackwell Publishing Ltd.

Studies on muon tomography for archaeological internal structures scanning

NASA Astrophysics Data System (ADS)

Gómez, H.; Carloganu, C.; Gibert, D.; Jacquemier, J.; Karyotakis, Y.; Marteau, J.; Niess, V.; Katsanevas, S.; Tonazzo, A.

2016-05-01

Muon tomography is a potential non-invasive technique for internal structure scanning. It has already interesting applications in geophysics and can be used for archaeological purposes. Muon tomography is based on the measurement of the muon flux after crossing the structure studied. Differences on the mean density of these structures imply differences on the detected muon rate for a given direction. Based on this principle, Monte Carlo simulations represent a useful tool to provide a model of the expected muon rate and angular distribution depending on the composition of the studied object, being useful to estimate the expected detected muons and to better understand the experimental results. These simulations are mainly dependent on the geometry and composition of the studied object and on the modelling of the initial muon flux at surface. In this work, the potential of muon tomography in archaeology is presented and evaluated with Monte Carlo simulations by estimating the differences on the muon rate due to the presence of internal structures and its composition. The influence of the chosen muon model at surface in terms of energy and angular distributions in the final result has been also studied.

Estimation of computed tomography dose index in cone beam computed tomography: MOSFET measurements and Monte Carlo simulations.

PubMed

Kim, Sangroh; Yoshizumi, Terry; Toncheva, Greta; Yoo, Sua; Yin, Fang-Fang; Frush, Donald

2010-05-01

To address the lack of accurate dose estimation method in cone beam computed tomography (CBCT), we performed point dose metal oxide semiconductor field-effect transistor (MOSFET) measurements and Monte Carlo (MC) simulations. A Varian On-Board Imager (OBI) was employed to measure point doses in the polymethyl methacrylate (PMMA) CT phantoms with MOSFETs for standard and low dose modes. A MC model of the OBI x-ray tube was developed using BEAMnrc/EGSnrc MC system and validated by the half value layer, x-ray spectrum and lateral and depth dose profiles. We compared the weighted computed tomography dose index (CTDIw) between MOSFET measurements and MC simulations. The CTDIw was found to be 8.39 cGy for the head scan and 4.58 cGy for the body scan from the MOSFET measurements in standard dose mode, and 1.89 cGy for the head and 1.11 cGy for the body in low dose mode, respectively. The CTDIw from MC compared well to the MOSFET measurements within 5% differences. In conclusion, a MC model for Varian CBCT has been established and this approach may be easily extended from the CBCT geometry to multi-detector CT geometry.

A Comparison of Ultrasound Tomography Methods in Circular Geometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leach, R R; Azevedo, S G; Berryman, J G

2002-01-24

Extremely high quality data was acquired using an experimental ultrasound scanner developed at Lawrence Livermore National Laboratory using a 2D ring geometry with up to 720 transmitter/receiver transducer positions. This unique geometry allows reflection and transmission modes and transmission imaging and quantification of a 3D volume using 2D slice data. Standard image reconstruction methods were applied to the data including straight-ray filtered back projection, reflection tomography, and diffraction tomography. Newer approaches were also tested such as full wave, full wave adjoint method, bent-ray filtered back projection, and full-aperture tomography. A variety of data sets were collected including a formalin-fixed humanmore » breast tissue sample, a commercial ultrasound complex breast phantom, and cylindrical objects with and without inclusions. The resulting reconstruction quality of the images ranges from poor to excellent. The method and results of this study are described including like-data reconstructions produced by different algorithms with side-by-side image comparisons. Comparisons to medical B-scan and x-ray CT scan images are also shown. Reconstruction methods with respect to image quality using resolution, noise, and quantitative accuracy, and computational efficiency metrics will also be discussed.« less

Effect of length and location of edentulous area on the accuracy of prosthetic treatment plan incorporation into cone-beam computed tomography scans.

PubMed

Jamjoom, Faris Z; Kim, Do-Gyoon; Lee, Damian J; McGlumphy, Edwin A; Yilmaz, Burak

2018-02-05

Effects of length and location of the edentulous area on the accuracy of prosthetic treatment plan incorporation into cone-beam computed tomography (CBCT) scans has not been investigated. To evaluate the effect of length and location of the edentulous area on the accuracy of prosthetic treatment plan incorporation into CBCT scans using different methods. Direct digital scans of a completely dentate master model with removable radiopaque teeth were made using an intraoral scanner, and digital scans of stone duplicates of the master model were made using a laboratory scanner. Specific teeth were removed to simulate different clinical situations and their CBCT scans were made. Surface scans were registered onto the CBCT scans. Radiographic templates for each clinical situation were also fabricated and used during CBCT scans of the master models. Using metrology software, three-dimensional (3D) deviation was measured on standard tesselation language (STL) files created from the CBCT scans against an STL file of the master model created from a CBCT scan. Statistical analysis was done using the MIXED procedure in a statistical software and Tukey HSD test (α =.05). The interaction between location and method was significant (P = .009). Location had no significant effect on registration methods (P > .05), but on the radiographic templates (P = .011). Length of the edentulous area did not have any significant effect (P > .05). Accuracy of digital image registration methods was similar and higher than that of radiographic templates in all clinical situations. Tooth-bound radiographic templates were significantly more accurate than the free-end templates. The results of this study suggest using image registration instead of radiographic templates when planning dental implants, particularly in free-end situations. © 2018 Wiley Periodicals, Inc.

A comparison of methods using optical coherence tomography to detect demineralized regions in teeth

PubMed Central

Sowa, Michael G.; Popescu, Dan P.; Friesen, Jeri R.; Hewko, Mark D.; Choo-Smith, Lin-P’ing

2013-01-01

Optical coherence tomography (OCT) is a three- dimensional optical imaging technique that can be used to identify areas of early caries formation in dental enamel. The OCT signal at 850 nm back-reflected from sound enamel is attenuated stronger than the signal back-reflected from demineralized regions. To quantify this observation, the OCT signal as a function of depth into the enamel (also known as the A-scan intensity), the histogram of the A-scan intensities and three summary parameters derived from the A-scan are defined and their diagnostic potential compared. A total of 754 OCT A-scans were analyzed. The three summary parameters derived from the A-scans, the OCT attenuation coefficient as well as the mean and standard deviation of the lognormal fit to the histogram of the A-scan ensemble show statistically significant differences (p < 0.01) when comparing parameters from sound enamel and caries. Furthermore, these parameters only show a modest correlation. Based on the area under the curve (AUC) of the receiver operating characteristics (ROC) plot, the OCT attenuation coefficient shows higher discriminatory capacity (AUC=0.98) compared to the parameters derived from the lognormal fit to the histogram of the A-scan. However, direct analysis of the A-scans or the histogram of A-scan intensities using linear support vector machine classification shows diagnostic discrimination (AUC = 0.96) comparable to that achieved using the attenuation coefficient. These findings suggest that either direct analysis of the A-scan, its intensity histogram or the attenuation coefficient derived from the descending slope of the OCT A-scan have high capacity to discriminate between regions of caries and sound enamel. PMID:22052833

Relative value of computed tomography scanning and venous sampling in establishing the cause of primary hyperaldosteronism.

PubMed

Sheaves, R; Goldin, J; Reznek, R H; Chew, S L; Dacie, J E; Lowe, D G; Ross, R J; Wass, J A; Besser, G M; Grossman, A B

1996-03-01

The purpose of this study was to evaluate the relative merits of the postural stimulation test, adrenal computed tomography (CT) and venous sampling in the differential diagnosis of patients presenting with primary hyperaldosteronism. The records of 20 patients presenting with primary hyperaldosteronism were reviewed retrospectively. There were 15 patients with a unilateral aldosterone-producing adenoma (APA), four patients with idiopathic hyperaldosteronism (IHA) and one patient with primary adrenal hyperplasia (PAH). The postural stimulation test was based on measurements of plasma aldosterone and renin activity at 08.00 h and at noon after 4 h of ambulation. The CT scans of the adrenals were reviewed by a single radiologist. Bilateral venous sampling of adrenal veins was attempted in all patients and blood collected for aldosterone and cortisol assay. Plasma aldosterone concentration increased after 4 h of standing in all cases of hyperplasia but was also demonstrated in 10/15 patients with a surgically-proven APA. If one defines a significant postural rise as being greater than 30%, then 8/15 patients with APA can be considered as being posturally responsive. Computed tomography scanning correctly identified all 15 cases of APA and also classified correctly the remaining five cases of hyperplasia (four cases of IHA and one case of PAH). Venous sampling failed technically in 4/15 cases of APA and in one case of IHA: a total of 5/20 (25%,). A correct diagnosis of APA or IHA was established in all the remaining cases. However, the one case of PAH was treated successfully by adrenalectomy following venous sampling, which suggested a unilateral adrenal lesion: this one result was the only instance where venous sampling altered clinical decision-making. Computed tomography scanning may be used alone to confirm the cause of hyperaldosteronism where postural studies suggest an adrenal adenoma, and such patients may be considered for early surgery. Venous catheterization studies are not necessary routinely. but may still be useful in selected patients, particularly when CT scanning shows no clear lesion.

A CAT scan for cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-01-01

Recently, a team of scientists from Berkeley Lab, Stanford University, and the University of California, San Francisco used Berkeley Lab's National Center for X-ray Tomography to capture the changes that occur when Candida albicans is exposed to a new and promising antifungal therapy. http://newscenter.lbl.gov/feature-stories/2009/12/10/cat-scan-cells/

Electrostatic forward-viewing scanning probe for Doppler optical coherence tomography using a dissipative polymer catheter.

PubMed

Munce, Nigel R; Mariampillai, Adrian; Standish, Beau A; Pop, Mihaela; Anderson, Kevan J; Liu, George Y; Luk, Tim; Courtney, Brian K; Wright, Graham A; Vitkin, I Alex; Yang, Victor X D

2008-04-01

A novel flexible scanning optical probe is constructed with a finely etched optical fiber strung through a platinum coil in the lumen of a dissipative polymer. The packaged probe is 2.2 mm in diameter with a rigid length of 6mm when using a ball lens or 12 mm when scanning the fiber proximal to a gradient-index (GRIN) lens. Driven by constant high voltage (1-3 kV) at low current (< 5 microA), the probe oscillates to provide wide forward-viewing angle (13 degrees and 33 degrees with ball and GRIN lens designs, respectively) and high-frame-rate (10-140 fps) operation. Motion of the probe tip is observed with a high-speed camera and compared with theory. Optical coherence tomography (OCT) imaging with the probe is demonstrated with a wavelength-swept source laser. Images of an IR card as well as in vivo Doppler OCT images of a tadpole heart are presented. This optomechanical design offers a simple, inexpensive method to obtain a high-frame-rate forward-viewing scanning probe.

Indications of Brain Computed Tomography Scan in Children Younger Than 3 Years of Age with Minor Head Trauma

PubMed Central

Gülşen, İsmail; Ak, Hakan; Karadaş, Sevdegül; Demır, İsmail; Bulut, Mehmet Deniz; Yaycioğlu, Soner

2014-01-01

Objective. To investigate the indications to receive brain computed tomography (CT) scan and to define the pathological findings in children younger than three years of age with minor head trauma in emergency departments. Methods. In this study, hospital case notes of 1350 children attending the emergency department of Bitlis State Hospital between January 2011 and June 2013 were retrospectively reviewed. 508 children under 3 years of age with minor head trauma were included in this study. We also asked 37 physicians about the indications for requiring CT in these children. Results. This study included 508 children, 233 (45,9%) of whom were female and 275 were male. In 476 (93,7%) children, the brain CT was completely normal. 89,2% of physicians asked in the emergency department during that time interval reported that they requested CT scan to protect themselves against malpractice litigation. Conclusion. In infants and children with minor head trauma, most CT scans were unnecessary and the fear of malpractice litigation of physicians was the most common reason for requesting a CT. PMID:24724031

Microscanners for optical endomicroscopic applications

NASA Astrophysics Data System (ADS)

Hwang, Kyungmin; Seo, Yeong-Hyeon; Jeong, Ki-Hun

2017-12-01

MEMS laser scanning enables the miniaturization of endoscopic catheters for advanced endomicroscopy such as confocal microscopy, multiphoton microscopy, optical coherence tomography, and many other laser scanning microscopy. These advanced biomedical imaging modalities open a great potential for in vivo optical biopsy without surgical excision. They have huge capabilities for detecting on-demand early stage cancer with non-invasiveness. In this article, the scanning arrangement, trajectory, and actuation mechanism of endoscopic microscanners and their endomicroscopic applications will be overviewed.

Individual A-Scan Signal Normalization Between Two Spectral Domain Optical Coherence Tomography Devices

PubMed Central

Chen, Chieh-Li; Ishikawa, Hiroshi; Wollstein, Gadi; Ling, Yun; Bilonick, Richard A.; Kagemann, Larry; Sigal, Ian A.; Schuman, Joel S.

2013-01-01

Purpose. We developed a method to normalize optical coherence tomography (OCT) signal profiles from two spectral-domain (SD) OCT devices so that the comparability between devices increases. Methods. We scanned 21 eyes from 14 healthy and 7 glaucoma subjects with two SD-OCT devices on the same day, with equivalent cube scan patterns centered on the fovea (Cirrus HD-OCT and RTVue). Foveola positions were selected manually and used as the center for registration of the corresponding images. A-scan signals were sampled 1.8 mm from the foveola in the temporal, superior, nasal, and inferior quadrants. After oversampling and rescaling RTVue data along the Z-axis to match the corresponding Cirrus data format, speckle noise reduction and amplitude normalization were applied. For comparison between normalized A-scan profiles, mean absolute difference in amplitude in percentage was measured at each sampling point. As a reference, the mean absolute difference between two Cirrus scans on the same eye also was measured. Results. The mean residual of the A-scan profile amplitude was reduced significantly after signal normalization (12.7% vs. 6.2%, P < 0.0001, paired t-test). All four quadrants also showed statistically significant reduction (all P < 0.0001). Mean absolute difference after normalization was smaller than the one between two Cirrus scans. No performance difference was detected between health and glaucomatous eyes. Conclusions. The reported signal normalization method successfully reduced the A-scan profile differences between two SD-OCT devices. This signal normalization processing may improve the direct comparability of OCT image analysis and measurement on various devices. PMID:23611992

Differences in regional air trapping in current smokers with normal spirometry.

PubMed

Karimi, Reza; Tornling, Göran; Forsslund, Helena; Mikko, Mikael; Wheelock, Åsa M; Nyrén, Sven; Sköld, C Magnus

2017-01-01

We investigated regional air trapping on computed tomography in current smokers with normal spirometry. It was hypothesised that presence of regional air trapping may indicate a specific manifestation of smoking-related changes.40 current smokers, 40 patients with chronic obstructive pulmonary disease (COPD), and 40 healthy never- smokers underwent computed tomography scans. Regional air trapping was assessed on end-expiratory scans and emphysema, micronodules and bronchial wall thickening on inspiratory scans. The ratio of expiratory and inspiratory mean lung attenuation (E/I) was calculated as a measure of static (fixed) air trapping.Regional air trapping was present in 63% of current smokers, in 45% of never smokers and in 8% of COPD patients (p<0.001). Current smokers with and without regional air trapping had E/I ratio of 0.81 and 0.91, respectively (p<0.001). Forced expiratory volume in 1 s (FEV 1 ) was significantly higher and emphysema less frequent in current smokers with regional air trapping.Current smokers with regional air trapping had higher FEV 1 and less emphysema on computed tomography. In contrast, current smokers without regional air trapping resembled COPD. Our results highlight heterogeneity among smokers with normal spirometry and may contribute to early detection of smoking related structural changes in the lungs. Copyright ©ERS 2017.

Ga-68 DOTA-NOC uptake in the pancreas: pathological and physiological patterns.

PubMed

Krausz, Yodphat; Rubinstein, Rina; Appelbaum, Liat; Mishani, Eyal; Orevi, Marina; Fraenkel, Merav; Tshori, Sagi; Glaser, Benjamin; Bocher, Moshe; Salmon, Asher; Chisin, Roland; Gross, David J; Freedman, Nanette

2012-01-01

Gallium-68 (Ga-68) DOTA-1-NaI3-octreotide (DOTA-NOC) positron emission tomography (PET)/computed tomography (CT) is increasingly used for neuroendocrine tumors (NETs), often found primarily in the pancreas. However, physiologic uptake of DOTA-NOC has been described in the uncinate process of the pancreas. We studied DOTA-NOC uptake in this organ. Ninety-six patients underwent 103 DOTA-NOC scans, with pathology-proven pancreatic NET (n = 40) and nonpancreatic NET or biochemical suspicion of NET (n = 63). DOTA-NOC uptake was detected in 35 documented pancreatic tumor sites (SUV: 5.5-165; mean: 25.7 ± 28.8; median: 17.8). Among 63 cases without previous known pathology, uptake was suspicious for tumor in 24 sites (SUV: 4.7-35; mean 16.3 ± 8.0; median: 14.1), and in 38 sites, it was judged as physiological, generally lower relative to adjacent structures (SUV: 2.2-12.6; mean: 6.6 ± 2.2; median: 6.2). In 24 scans with suspected tumor and in 37 of 38 scans with physiological uptake, diagnostic computed tomography or magnetic resonance imaging or endoscopic ultrasonography failed to detect tumor. Pancreatic DOTA-NOC uptake must be interpreted with caution, and further studies are required.

Mcps-range photon-counting X-ray computed tomography system utilizing an oscillating linear-YAP(Ce) photon detector

NASA Astrophysics Data System (ADS)

Oda, Yasuyuki; Sato, Eiichi; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sugimura, Shigeaki; Endo, Haruyuki; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-07-01

High-speed X-ray photon counting is useful for discriminating photon energy, and the counting can be used for constructing an X-ray computed tomography (CT) system. A photon-counting X-ray CT system consists of an X-ray generator, a turntable, an oscillation linear detector, a two-stage controller, a multipixel photon counter (MPPC) module, a 1.0 mm-thick crystal (scintillator) of YAP(Ce) (cerium-doped yttrium aluminum perovskite), a counter card (CC), and a personal computer (PC). Tomography is accomplished by repeating the linear scanning and the rotation of an object, and projection curves of the object are obtained by the linear scanning using the detector consisting of an MPPC module, the YAP(Ce), and a scan stage. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. Because the lower level of the photon energy was roughly determined by a comparator in the module, the average photon energy of the X-ray spectra increased with increase in the lower-level voltage of the comparator at a constant tube voltage. The maximum count rate was approximately 3 Mcps (mega counts per second), and photon-counting CT was carried out.

Physical analysis of breast cancer using dual-source computed tomography

NASA Astrophysics Data System (ADS)

Kim, H. J.; Lee, H. K.; Cho, J. H.

2014-12-01

This study was aimed to analyze various physical characteristics of breast cancer using dual-source computed tomography (CT). A phantom study and a clinical trial were performed in order and a 64-multidetector CT device was used for the examinations. In the phantom study, single-source (SS) CT was set up with a conventional scanning condition that is usually applied for breast CT examination and implementation was done at tube voltage of 120 kVp. Dual-source CT acquired images by irradiating X-ray sources with fast switching between two kilovoltage settings (80 and 140 kVp). After scanning, Hounsfield Unit (HU) values and radiation doses in a region of interest were measured and analyzed. In the clinical trial, the HU values were measured and analyzed after single-source computed tomography (SSCT) and dual-source CT in patients diagnosed with breast cancer. Also, the tumor size measured by dual-source CT was compared with the actual tumor size. The phantom study determined that the tumor region was especially measured by dual-source CT, while nylon fiber and specks region were especially measured by SSCT. The radiation dose was high with dual-source CT. The clinical trial showed a higher HU value of cancerous regions when scanned by dual-source CT compared with SSCT.

Use of cone beam computed tomography in implant dentistry: current concepts, indications and limitations for clinical practice and research.

PubMed

Bornstein, Michael M; Horner, Keith; Jacobs, Reinhilde

2017-02-01

Diagnostic radiology is an essential component of treatment planning in the field of implant dentistry. This narrative review will present current concepts for the use of cone beam computed tomography imaging, before and after implant placement, in daily clinical practice and research. Guidelines for the selection of three-dimensional imaging will be discussed, and limitations will be highlighted. Current concepts of radiation dose optimization, including novel imaging modalities using low-dose protocols, will be presented. For preoperative cross-sectional imaging, data are still not available which demonstrate that cone beam computed tomography results in fewer intraoperative complications such as nerve damage or bleeding incidents, or that implants inserted using preoperative cone beam computed tomography data sets for planning purposes will exhibit higher survival or success rates. The use of cone beam computed tomography following the insertion of dental implants should be restricted to specific postoperative complications, such as damage of neurovascular structures or postoperative infections in relation to the maxillary sinus. Regarding peri-implantitis, the diagnosis and severity of the disease should be evaluated primarily based on clinical parameters and on radiological findings based on periapical radiographs (two dimensional). The use of cone beam computed tomography scans in clinical research might not yield any evident beneficial effect for the patient included. As many of the cone beam computed tomography scans performed for research have no direct therapeutic consequence, dose optimization measures should be implemented by using appropriate exposure parameters and by reducing the field of view to the actual region of interest. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Multi-detector row computed tomography angiography of peripheral arterial disease

PubMed Central

Dijkshoorn, Marcel L.; Pattynama, Peter M. T.; Myriam Hunink, M. G.

2007-01-01

With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD. PMID:17882427

In-vivo, real-time cross-sectional images of retina using a GPU enhanced master slave optical coherence tomography system

NASA Astrophysics Data System (ADS)

Bradu, Adrian; Kapinchev, Konstantin; Barnes, Frederick; Podoleanu, Adrian

2016-03-01

In our previous reports we demonstrated a novel Fourier domain optical coherence tomography method, Master Slave optical coherence tomography (MS-OCT), that does not require resampling of data and can deliver en-face images from several depths simultaneously. While ideally suited for delivering information from a selected depth, the MS-OCT has been so far inferior to the conventional FFT based OCT in terms of time of producing cross section images. Here, we demonstrate that by taking advantage of the parallel processing capabilities offered by the MS-OCT method, cross-sectional OCT images of the human retina can be produced in real-time by assembling several T-scans from different depths. We analyze the conditions that ensure a real-time B-scan imaging operation, and demonstrate in-vivo real-time images from human fovea and the optic nerve, of comparable resolution and sensitivity to those produced using the traditional Fourier domain based method.

Treatment of eight dogs with nasal tumours with alternating doses of doxorubicin and carboplatin in conjunction with oral piroxicam.

PubMed

Langova, V; Mutsaers, A J; Phillips, B; Straw, R

2004-11-01

To determine the efficacy and toxicity of chemotherapy in the treatment of canine nasal tumours. Retrospective clinical study Eight dogs with histologically confirmed nasal tumours were staged by means of complete blood count, serum biochemical analysis, cytological analysis of fine needle aspirate of the regional lymph nodes, thoracic radiographs and computed tomography scan of the nasal cavity. All dogs were treated with alternating doses of doxorubicin, carboplatin and oral piroxicam. All dogs were monitored for side effects of chemotherapy and evaluated for response to treatment by computed tomography scan of the nasal cavity after the first four treatments. Complete remission was achieved in four dogs, partial remission occurred in two dogs and two had stable disease on the basis of computed tomography evaluation. There was resolution of clinical signs after one to two doses of chemotherapy in all dogs. This chemotherapy protocol was efficacious and well tolerated in this series of eight cases of canine nasal tumours.

A review of imaging modalities in pulmonary hypertension

PubMed Central

Ascha, Mona; Renapurkar, Rahul D.; Tonelli, Adriano R.

2017-01-01

Pulmonary hypertension (PH) is defined as resting mean pulmonary artery pressure ≥25 mmHg measured by right heart catheterization. PH is a progressive, life-threatening disease with a variety of etiologies. Swift and accurate diagnosis of PH and appropriate classification in etiologic group will allow for earlier treatment and improved outcomes. A number of imaging tools are utilized in the evaluation of PH, such as chest X-ray, computed tomography (CT), ventilation/perfusion (V/Q) scan, and cardiac magnetic resonance imaging. Newer imaging tools such as dual-energy CT and single-photon emission computed tomography/computed tomography V/Q scanning have also emerged; however, their place in the diagnostic evaluation of PH remains to be determined. In general, each imaging technique provides incremental information, with varying degrees of sensitivity and specificity, which helps suspect the presence and identify the etiology of PH. The present study aims to provide a comprehensive review of the utility, advantages, and shortcomings of the imaging modalities that may be used to evaluate patients with PH. PMID:28469715

High-resolution synchrotron radiation-based phase tomography of the healthy and epileptic brain

NASA Astrophysics Data System (ADS)

Bikis, Christos; Janz, Philipp; Schulz, Georg; Schweighauser, Gabriel; Hench, Jürgen; Thalmann, Peter; Deyhle, Hans; Chicherova, Natalia; Rack, Alexander; Khimchenko, Anna; Hieber, Simone E.; Mariani, Luigi; Haas, Carola A.; Müller, Bert

2016-10-01

Phase-contrast micro-tomography using synchrotron radiation has yielded superior soft tissue visualization down to the sub-cellular level. The isotropic spatial resolution down to about one micron is comparable to the one of histology. The methods, however, provide different physical quantities and are thus complementary, also allowing for the extension of histology into the third dimension. To prepare for cross-sectional animal studies on epilepsy, we have standardized the specimen's preparation and scanning procedure for mouse brains, so that subsequent histology remains entirely unaffected and scanning of all samples (n = 28) is possible in a realistic time frame. For that, we have scanned five healthy and epileptic mouse brains at the ID19 beamline, ESRF, Grenoble, France, using grating- and propagation-based phase contrast micro-tomography. The resulting datasets clearly show the cortex, ventricular system, thalamus, hypothalamus, and hippocampus. Our focus is on the latter, having planned kainate-induced epilepsy experiments. The cell density and organization in the dentate gyrus and Ammon's horn region were clearly visualized in control animals. This proof of principle was required to initiate experiment. The resulting three-dimensional data have been correlated to histology. The goal is a brain-wide quantification of cell death or structural reorganization associated with epilepsy as opposed to histology alone that represents small volumes of the total brain only. Thus, the proposed technique bears the potential to correlate the gold standard in analysis with independently obtained data sets. Such an achievement also fuels interest for other groups in neuroscience research to closely collaborate with experts in phase micro-tomography.

Evaluation of a completely robotized neurosurgical operating microscope.

PubMed

Kantelhardt, Sven R; Finke, Markus; Schweikard, Achim; Giese, Alf

2013-01-01

Operating microscopes are essential for most neurosurgical procedures. Modern robot-assisted controls offer new possibilities, combining the advantages of conventional and automated systems. We evaluated the prototype of a completely robotized operating microscope with an integrated optical coherence tomography module. A standard operating microscope was fitted with motors and control instruments, with the manual control mode and balance preserved. In the robot mode, the microscope was steered by a remote control that could be fixed to a surgical instrument. External encoders and accelerometers tracked microscope movements. The microscope was additionally fitted with an optical coherence tomography-scanning module. The robotized microscope was tested on model systems. It could be freely positioned, without forcing the surgeon to take the hands from the instruments or avert the eyes from the oculars. Positioning error was about 1 mm, and vibration faded in 1 second. Tracking of microscope movements, combined with an autofocus function, allowed determination of the focus position within the 3-dimensional space. This constituted a second loop of navigation independent from conventional infrared reflector-based techniques. In the robot mode, automated optical coherence tomography scanning of large surface areas was feasible. The prototype of a robotized optical coherence tomography-integrated operating microscope combines the advantages of a conventional manually controlled operating microscope with a remote-controlled positioning aid and a self-navigating microscope system that performs automated positioning tasks such as surface scans. This demonstrates that, in the future, operating microscopes may be used to acquire intraoperative spatial data, volume changes, and structural data of brain or brain tumor tissue.

Effect of field-of-view size on gray values derived from cone-beam computed tomography compared with the Hounsfield unit values from multidetector computed tomography scans.

PubMed

Shokri, Abbas; Ramezani, Leila; Bidgoli, Mohsen; Akbarzadeh, Mahdi; Ghazikhanlu-Sani, Karim; Fallahi-Sichani, Hamed

2018-03-01

This study aimed to evaluate the effect of field-of-view (FOV) size on the gray values derived from conebeam computed tomography (CBCT) compared with the Hounsfield unit values from multidetector computed tomography (MDCT) scans as the gold standard. A radiographic phantom was designed with 4 acrylic cylinders. One cylinder was filled with distilled water, and the other 3 were filled with 3 types of bone substitute: namely, Nanobone, Cenobone, and Cerabone. The phantom was scanned with 2 CBCT systems using 2 different FOV sizes, and 1 MDCT system was used as the gold standard. The mean gray values (MGVs) of each cylinder were calculated in each imaging protocol. In both CBCT systems, significant differences were noted in the MGVs of all materials between the 2 FOV sizes ( P <.05) except for Cerabone in the Cranex3D system. Significant differences were found in the MGVs of each material compared with the others in both FOV sizes for each CBCT system. No significant difference was seen between the Cranex3D CBCT system and the MDCT system in the MGVs of bone substitutes on images obtained with a small FOV. The size of the FOV significantly changed the MGVs of all bone substitutes, except for Cerabone in the Cranex3D system. Both CBCT systems had the ability to distinguish the 3 types of bone substitutes based on a comparison of their MGVs. The Cranex3D CBCT system used with a small FOV had a significant correlation with MDCT results.

Handheld Optical Coherence Tomography Angiography and Ultra-Wide-Field Optical Coherence Tomography in Retinopathy of Prematurity.

PubMed

Campbell, J Peter; Nudleman, Eric; Yang, Jianlong; Tan, Ou; Chan, R V Paul; Chiang, Michael F; Huang, David; Liu, Gangjun

2017-09-01

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness worldwide. Optical coherence tomography (OCT) has improved the care of adults with vitreoretinal disease, and OCT angiography (OCTA) is demonstrating promise as a technique to visualize the retinal vasculature with lower risk and cost than fluorescein angiography. However, to date, there are no commercially available devices able to obtain ultra-wide-field OCT or OCTA images in neonates. To obtain ultra-wide-field OCT and OCTA images in neonates with ROP using a prototype handheld OCT and OCTA device. This observational case series was conducted from March 1 to April 1, 2017, in an academic medical center among 4 neonates with ROP in the neonatal intensive care unit and in the operating room. Acquisition of wide-field OCT and OCTA images using a handheld prototype OCTA and ultra-wide-field OCT device. Images were obtained from 4 neonates (1 girl and 3 boys; mean age, 38 weeks' postmenstrual age [range, 34-43 weeks]) with various stages of ROP: 3 in the neonatal intensive care unit and 1 in the operating room. The system can obtain noncontact en face OCT images and horizontal line scans with an approximately 40° field of view and up to 100° (ultra-wide-field) using a contact lens-based approach in a single 2-second scan. In addition, 20° × 20° (approximately 4 × 4-mm) OCTA scans were obtained in patients with ROP in a single 2-second scan. Optical coherence tomography and OCTA are gaining popularity in pediatric retinal imaging. This study reports on OCTA and ultra-wide-field OCT images in 4 neonates with various stages of ROP that were obtained using a prototype handheld device. Additional studies will be needed to prove the clinical value of this technology.

Usefulness of Positron Emission Tomography in Patients with Syphilis: A Systematic Review of Observational Studies.

PubMed

Chen, Jian-Hua; Zheng, Xin; Liu, Xiu-Qin

2017-05-05

Diagnosis of syphilis is difficult. Follow-up and therapy evaluation of syphilitic patients are poor. Little is known about positron emission tomography (PET) in syphilis. This review was to systematically review usefulness of PET for diagnosis, disease extent evaluation, follow-up, and treatment response assessment in patients with syphilis. We searched PubMed, EMBASE, SCOPUS, Cochrane Library, Web of Science, ClinicalTrials.gov, and three Chinese databases (SinoMed, Wanfang, and CNKI) for English and Chinese language articles from inception to September 2016. We also collected potentially relevant studies and reviews using a manual search. The search keywords included the combined text and MeSH terms "syphilis" and "positron emission tomography". We included studies that reporting syphilis with a PET scan before and/or after antibiotic treatment. The diagnosis of syphilis was based on serological criteria or dark field microscopy. Outcomes include pre- and post-treatment PET scan, pre- and post-treatment computed tomography, and pre- and post-treatment magnetic resonance imaging. We excluded the articles not published in English or Chinese or not involving humans. Of 258 identified articles, 34 observational studies were included. Thirty-three studies were single-patient case reports and one study was a small case series. All patients were adults. The mean age of patients was 48.3 ± 12.1 years. In primary syphilis, increased fluorodeoxyglucose (FDG) accumulation could be seen at the site of inoculation or in the regional lymph nodes. In secondary syphilis with lung, bone, gastrointestinal involvement, or generalized lymphadenopathy, increased FDG uptake was the most commonly detected changes. In tertiary syphilis, increased glucose metabolic activity, hypometabolic lesions, or normal glucose uptake might be seen on PET. There were five types of PET scans in neurosyphilis. A repeated PET scan after treatment revealed apparent or complete resolution of the asymmetry of radiotracer uptake. PET is helpful in targeting diagnostic interventions, characterizing disease extent, assessing nodal involvement, and treatment efficacy for syphilis.

Clinical application of calculated split renal volume using computed tomography-based renal volumetry after partial nephrectomy: Correlation with technetium-99m dimercaptosuccinic acid renal scan data.

PubMed

Lee, Chan Ho; Park, Young Joo; Ku, Ja Yoon; Ha, Hong Koo

2017-06-01

To evaluate the clinical application of computed tomography-based measurement of renal cortical volume and split renal volume as a single tool to assess the anatomy and renal function in patients with renal tumors before and after partial nephrectomy, and to compare the findings with technetium-99m dimercaptosuccinic acid renal scan. The data of 51 patients with a unilateral renal tumor managed by partial nephrectomy were retrospectively analyzed. The renal cortical volume of tumor-bearing and contralateral kidneys was measured using ImageJ software. Split estimated glomerular filtration rate and split renal volume calculated using this renal cortical volume were compared with the split renal function measured with technetium-99m dimercaptosuccinic acid renal scan. A strong correlation between split renal function and split renal volume of the tumor-bearing kidney was observed before and after surgery (r = 0.89, P < 0.001 and r = 0.94, P < 0.001). The preoperative and postoperative split estimated glomerular filtration rate of the operated kidney showed a moderate correlation with split renal function (r = 0.39, P = 0.004 and r = 0.49, P < 0.001). The correlation between reductions in split renal function and split renal volume of the operated kidney (r = 0.87, P < 0.001) was stronger than that between split renal function and percent reduction in split estimated glomerular filtration rate (r = 0.64, P < 0.001). The split renal volume calculated using computed tomography-based renal volumetry had a strong correlation with the split renal function measured using technetium-99m dimercaptosuccinic acid renal scan. Computed tomography-based split renal volume measurement before and after partial nephrectomy can be used as a single modality for anatomical and functional assessment of the tumor-bearing kidney. © 2017 The Japanese Urological Association.

Inner structure detection by optical tomography technology based on feedback of microchip Nd:YAG lasers.

PubMed

Xu, Chunxin; Zhang, Shulian; Tan, Yidong; Zhao, Shijie

2013-05-20

We describe a new optical tomography technology based on feedback of microchip Nd:YAG lasers. In the case of feedback light frequency-shifted, light can be magnified by a fact of 10(6) in the Nd:YAG microchip lasers, which makes it possible to realize optical tomography with a greater depth than current optical tomography. The results of the measuring and imaging of kinds of samples are presented, which demonstrate the feasibility and potential of this approach in the inner structure detection. The system has a lateral resolution of ~1 μm, a vertical resolution of 15 μm and a longitudinal scanning range of over 10mm.

Automatic contour propagation using deformable image registration to determine delivered dose to spinal cord in head-and-neck cancer radiotherapy.

PubMed

Yeap, P L; Noble, D J; Harrison, K; Bates, A M; Burnet, N G; Jena, R; Romanchikova, M; Sutcliffe, M P F; Thomas, S J; Barnett, G C; Benson, R J; Jefferies, S J; Parker, M A

2017-07-12

To determine delivered dose to the spinal cord, a technique has been developed to propagate manual contours from kilovoltage computed-tomography (kVCT) scans for treatment planning to megavoltage computed-tomography (MVCT) guidance scans. The technique uses the Elastix software to perform intensity-based deformable image registration of each kVCT scan to the associated MVCT scans. The registration transform is then applied to contours of the spinal cord drawn manually on the kVCT scan, to obtain contour positions on the MVCT scans. Different registration strategies have been investigated, with performance evaluated by comparing the resulting auto-contours with manual contours, drawn by oncologists. The comparison metrics include the conformity index (CI), and the distance between centres (DBC). With optimised registration, auto-contours generally agree well with manual contours. Considering all 30 MVCT scans for each of three patients, the median CI is [Formula: see text], and the median DBC is ([Formula: see text]) mm. An intra-observer comparison for the same scans gives a median CI of [Formula: see text] and a DBC of ([Formula: see text]) mm. Good levels of conformity are also obtained when auto-contours are compared with manual contours from one observer for a single MVCT scan for each of 30 patients, and when they are compared with manual contours from six observers for two MVCT scans for each of three patients. Using the auto-contours to estimate organ position at treatment time, a preliminary study of 33 patients who underwent radiotherapy for head-and-neck cancers indicates good agreement between planned and delivered dose to the spinal cord.

With "big data" comes big responsibility: outreach to North Carolina Medicaid patients with 10 or more computed tomography scans in 12 months.

PubMed

Biola, Holly; Best, Randall M; Lahlou, Rita M; Burke, Lauren M; Dewar, Charles; Jackson, Carlos T; Broder, Joshua; Grey, Linda; Semelka, Richard C; Dobson, Allen

2014-01-01

Patients are being exposed to increasing levels of ionizing radiation, much of it from computed tomography (CT) scans. Adults without a cancer diagnosis who received 10 or more CT scans in 2010 were identified from North Carolina Medicaid claims data and were sent a letter in July 2011 informing them of their radiation exposure; those who had undergone 20 or more CT scans in 2010 were also telephoned. The CT scan exposure of these high-exposure patients during the 12 months following these interventions was compared with that of adult Medicaid patients without cancer who had at least 1 CT scan but were not in the intervention population. The average number of CT scans per month for the high-exposure population decreased over time, but most of that reduction occurred 6-9 months before our interventions took place. At about the same time, the number of CT scans per month also decreased in adult Medicaid patients without cancer who had at least 1 CT scan but were not in the intervention population. Our data do not include information about CT scans that may have been performed during times when patients were not covered by Medicaid. Some of our letters may not have been received or understood. Some high-exposure patients were unintentionally excluded from our study because organization of data on Medicaid claims varies by setting of care. Our patient education intervention was not temporally associated with significant decreases in subsequent CT exposure. Effecting behavior change to reduce exposure to ionizing radiation requires more than an educational letter or telephone call.

Detection and characterization of Budd-Chiari syndrome with inferior vena cava obstruction: Comparison of fixed and flexible delayed scan time of computed tomography venography.

PubMed

Zhou, Peng-Li; Wu, Gang; Han, Xin-Wei; Bi, Yong-Hua; Zhang, Wen-Guang; Wu, Zheng-Yang

2017-06-01

To compare the results of computed tomography venography (CTV) with a fixed and a flexible delayed scan time for Budd-Chiari syndrome (BCS) with inferior vena cava (IVC) obstruction. A total of 209 consecutive BCS patients with IVC obstruction underwent either a CTV with a fixed delayed scan time of 180s (n=87) or a flexible delayed scan time for good image quality according to IVC blood flow in color Doppler ultrasonography (n=122). The IVC blood flow velocity was measured using a color Doppler ultrasound prior to CT scan. Image quality was classified as either good, moderate, or poor. Image quality, surrounding structures and the morphology of the IVC obstruction were compared between the two groups using a χ 2 -test or paired or unpaired t-tests as appropriate. Inter-observer agreement was assessed using Kappa statistics. There was no significant difference in IVC blood flow velocity between the two groups. Overall image quality, surrounding structures and IVC obstruction morphology delineation on the flexible delayed scan time of CTV images were rated better relative to those obtained by fixed delayed scan time of CTV images (p<0.001). Evaluation of CTV data sets was significantly facilitated with flexible delayed scan time of CTV. There were no significant differences in Kappa statistics between Group A and Group B. The flexible delayed scan time of CTV was associated with better detection and more reliable characterization of BCS with IVC obstruction compared to a fixed delayed scan time. Copyright © 2017 Elsevier B.V. All rights reserved.

The utility of computed tomography in the management of fever and neutropenia in pediatric oncology.

PubMed

Rao, Avani D; Sugar, Elizabeth A; Barrett, Neil; Mahesh, Mahadevappa; Arceci, Robert J

2015-10-01

Despite the frequent use and radiation exposure of computed tomography (CT) scans, there is little information on patterns of CT use and their utility in the management of pediatric patients with fever and neutropenia (FN). We examined the contribution of either the commonly employed pan-CT (multiple anatomical locations) or targeted CT (single location) scanning to identify possible infectious etiologies in this challenging clinical scenario. Procedure Pediatric patients with an underlying malignancy admitted for fever (temperature ≥ 38.3 °C) and an absolute neutrophil count <500 cells/μL from 2003-2009 were included. Risk factors associated with utilization, results, and effects on clinical management of CT scans were identified. Results Charts for 635 admissions for FN from 263 patients were reviewed. Overall, 139 (22%) admissions (93 individuals) had at least one scan. Of 188 scans, 103 (55%) were pan-scans. Changes in management were most strongly associated with the identification of evidence consistent with infection (OR = 12.64, 95% CI: 5.05-31.60, P < 0.001). Seventy-eight (41%) of all CT scans led to a change in clinical management, most commonly relating to use of antibiotic (N = 41, 53%) or antifungal/antiviral medications (N = 33, 42%). The odds of a change in clinical management did not differ for those receiving a pan-scan compared to those receiving a targeted scan (OR = 1.23; 95% CI, 0.61-2.46; P = 0.57). Conclusions When CT is clinically indicated, it is important for clinicians to strongly consider utilizing a targeted scan to reduce radiation exposure to patients as well as to decrease costs without compromising care. © 2015 Wiley Periodicals, Inc.

Automatic contour propagation using deformable image registration to determine delivered dose to spinal cord in head-and-neck cancer radiotherapy

NASA Astrophysics Data System (ADS)

Yeap, P. L.; Noble, D. J.; Harrison, K.; Bates, A. M.; Burnet, N. G.; Jena, R.; Romanchikova, M.; Sutcliffe, M. P. F.; Thomas, S. J.; Barnett, G. C.; Benson, R. J.; Jefferies, S. J.; Parker, M. A.

2017-08-01

To determine delivered dose to the spinal cord, a technique has been developed to propagate manual contours from kilovoltage computed-tomography (kVCT) scans for treatment planning to megavoltage computed-tomography (MVCT) guidance scans. The technique uses the Elastix software to perform intensity-based deformable image registration of each kVCT scan to the associated MVCT scans. The registration transform is then applied to contours of the spinal cord drawn manually on the kVCT scan, to obtain contour positions on the MVCT scans. Different registration strategies have been investigated, with performance evaluated by comparing the resulting auto-contours with manual contours, drawn by oncologists. The comparison metrics include the conformity index (CI), and the distance between centres (DBC). With optimised registration, auto-contours generally agree well with manual contours. Considering all 30 MVCT scans for each of three patients, the median CI is 0.759 +/- 0.003 , and the median DBC is (0.87 +/- 0.01 ) mm. An intra-observer comparison for the same scans gives a median CI of 0.820 +/- 0.002 and a DBC of (0.64 +/- 0.01 ) mm. Good levels of conformity are also obtained when auto-contours are compared with manual contours from one observer for a single MVCT scan for each of 30 patients, and when they are compared with manual contours from six observers for two MVCT scans for each of three patients. Using the auto-contours to estimate organ position at treatment time, a preliminary study of 33 patients who underwent radiotherapy for head-and-neck cancers indicates good agreement between planned and delivered dose to the spinal cord.

Low Yield of Paired Head and Cervical Spine Computed Tomography in Blunt Trauma Evaluation.

PubMed

Graterol, Joseph; Beylin, Maria; Whetstone, William D; Matzoll, Ashleigh; Burke, Rennie; Talbott, Jason; Rodriguez, Robert M

2018-06-01

With increased computed tomography (CT) utilization, clinicians may simultaneously order head and neck CT scans, even when injury is suspected only in one region. We sought to determine: 1) the frequency of simultaneous ordering of a head CT scan when a neck CT scan is ordered; 2) the yields of simultaneously ordered head and neck CT scans for clinically significant injury (CSI); and 3) whether injury in one region is associated with a higher rate of injury in the other. This was a retrospective study of all adult patients who received neck CT scans (and simultaneously ordered head CT scans) as part of their blunt trauma evaluation at an urban level 1 trauma center in 2013. An expert panel determined CSI of head and neck injuries. We defined yield as number of patients with injury/number of patients who had a CT scan. Of 3223 patients who met inclusion criteria, 2888 (89.6%) had simultaneously ordered head and neck CT scans. CT yield for CSI in both the head and neck was 0.5% (95% confidence interval [CI] 0.3-0.8%), and the yield for any injury in both the head and neck was 1.4% (95% CI 1.0-1.8%). The yield for CSI in one region was higher when CSI was seen in the other region. The yield of CT for CSI in both the head and neck concomitantly is very low. When injury is seen in one region, there is higher likelihood of injury in the other. These findings argue against paired ordering of head and neck CT scans and suggest that CT scans should be ordered individually or when injury is detected in one region. Copyright © 2018 Elsevier Inc. All rights reserved.

Computed Tomography Status

DOE R&D Accomplishments Database

Hansche, B. D.

1983-01-01

Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

Local X-ray Computed Tomography Imaging for Mineralogical and Pore Characterization

NASA Astrophysics Data System (ADS)

Mills, G.; Willson, C. S.

2015-12-01

Sample size, material properties and image resolution are all tradeoffs that must be considered when imaging porous media samples with X-ray computed tomography. In many natural and engineered samples, pore and throat sizes span several orders of magnitude and are often correlated with the material composition. Local tomography is a nondestructive technique that images a subvolume, within a larger specimen, at high resolution and uses low-resolution tomography data from the larger specimen to reduce reconstruction error. The high-resolution, subvolume data can be used to extract important fine-scale properties but, due to the additional noise associated with the truncated dataset, it makes segmentation of different materials and mineral phases a challenge. The low-resolution data of a larger specimen is typically of much higher-quality making material characterization much easier. In addition, the imaging of a larger domain, allows for mm-scale bulk properties and heterogeneities to be determined. In this research, a 7 mm diameter and ~15 mm in length sandstone core was scanned twice. The first scan was performed to cover the entire diameter and length of the specimen at an image voxel resolution of 4.1 μm. The second scan was performed on a subvolume, ~1.3 mm in length and ~2.1 mm in diameter, at an image voxel resolution of 1.08 μm. After image processing and segmentation, the pore network structure and mineralogical features were extracted from the low-resolution dataset. Due to the noise in the truncated high-resolution dataset, several image processing approaches were applied prior to image segmentation and extraction of the pore network structure and mineralogy. Results from the different truncated tomography segmented data sets are compared to each other to evaluate the potential of each approach in identifying the different solid phases from the original 16 bit data set. The truncated tomography segmented data sets were also compared to the whole-core tomography segmented data set in two ways: (1) assessment of the porosity and pore size distribution at different scales; and (2) comparison of the mineralogical composition and distribution. Finally, registration of the two datasets will be used to show how the pore structure and mineralogy details at the two scales can be used to supplement each other.

Recent advances in electron tomography: TEM and HAADF-STEM tomography for materials science and semiconductor applications.

PubMed

Kübel, Christian; Voigt, Andreas; Schoenmakers, Remco; Otten, Max; Su, David; Lee, Tan-Chen; Carlsson, Anna; Bradley, John

2005-10-01

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials. Our analysis of catalysts, a hydrogen storage material, and different semiconductor devices shows that features with a diameter as small as 1-2 nm can be resolved in three dimensions by electron tomography. For partially crystalline materials with small single crystalline domains, bright-field TEM tomography provides reliable 3D structural information. HAADF-STEM tomography is more versatile and can also be used for high-resolution 3D imaging of highly crystalline materials such as semiconductor devices.

Design and evaluation of an intraocular B-scan OCT-guided 36-gauge needle

NASA Astrophysics Data System (ADS)

Shen, Jin H.; Joos, Karen M.

2015-03-01

Optical coherence tomography imaging is widely used in ophthalmology and optometry clinics for diagnosing retinal disorders. External microscope-mounted OCT operating room systems have imaged retinal changes immediately following surgical manipulations. However, the goal is to image critical surgical maneuvers in real time. External microscope-mounted OCT systems have some limitations with problems tracking constantly moving intraocular surgical instruments, and formation of absolute shadows by the metallic surgical instruments upon the underlying tissues of interest. An intraocular OCT-imaging probe was developed to resolve these problems. A disposable 25-gauge probe tip extended beyond the handpiece, with a 36-gauge needle welded to a disposable tip with its end extending an additional 3.5 mm. A sealed 0.35 mm diameter GRIN lens protected the fiber scanner and focused the scanning beam at a 3 to 4 mm distance. The OCT engine was a very high-resolution spectral-domain optical coherence tomography (SDOCT) system (870 nm, Bioptigen, Inc. Durham, NC) which produced 2000 A-scan lines per B-scan image at a frequency of 5 Hz with the fiber optic oscillations matched to this frequency. Real-time imaging of the needle tip as it touched infrared paper was performed. The B-scan OCT-needle was capable of real-time performance and imaging of the phantom material. In the future, the B-scan OCT-guided needle will be used to perform sub-retinal injections.

Dental image replacement on cone beam computed tomography with three-dimensional optical scanning of a dental cast, occlusal bite, or bite tray impression.

PubMed

Kang, S-H; Lee, J-W; Lim, S-H; Kim, Y-H; Kim, M-K

2014-10-01

The goal of the present study was to compare the accuracy of dental image replacement on a cone beam computed tomography (CBCT) image using digital image data from three-dimensional (3D) optical scanning of a dental cast, occlusal bite, and bite tray impression. A Bracket Typodont dental model was used. CBCT of the dental model was performed and the data were converted to stereolithography (STL) format. Three experimental materials, a dental cast, occlusal bite, and bite tray impression, were optically scanned in 3D. STL files converted from the CBCT of the Typodont model and the 3D optical-scanned STL files of the study materials were image-registered. The error range of each methodology was measured and compared with a 3D optical scan of the Typodont. For the three materials, the smallest error observed was 0.099±0.114mm (mean error±standard deviation) for registering the 3D optical scan image of the dental cast onto the CBCT dental image. Although producing a dental cast can be laborious, the study results indicate that it is the preferred method. In addition, an occlusal bite is recommended when bite impression materials are used. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography

PubMed Central

Ueno, Tomoka; Shimada, Yasushi; Matin, Khairul; Zhou, Yuan; Wada, Ikumi; Sadr, Alireza; Sumi, Yasunori; Tagami, Junji

2016-01-01

Abstract. The aim of this study was to evaluate the signal intensity and signal attenuation of swept source optical coherence tomography (SS-OCT) for dental caries in relation to the variation of mineral density. SS-OCT observation was performed on the enamel and dentin artificial demineralization and on natural caries. The artificial caries model on enamel and dentin surfaces was created using Streptococcus mutans biofilms incubated in an oral biofilm reactor. The lesions were centrally cross sectioned and SS-OCT scans were obtained in two directions to construct a three-dimensional data set, from the lesion surface (sagittal scan) and parallel to the lesion surface (horizontal scan). The integrated signal up to 200  μm in depth (IS200) and the attenuation coefficient (μ) of the enamel and dentin lesions were calculated from the SS-OCT signal in horizontal scans at five locations of lesion depth. The values were compared with the mineral density obtained from transverse microradiography. Both enamel and dentin demineralization showed significantly higher IS200 and μ than the sound tooth substrate from the sagittal scan. Enamel demineralization showed significantly higher IS200 than sound enamel, even with low levels of demineralization. In demineralized dentin, the μ from the horizontal scan consistently trended downward compared to the sound dentin. PMID:27704033

Prevalence of Extracochlear Electrodes: Computerized Tomography Scans, Cochlear Implant Maps, and Operative Reports.

PubMed

Holder, Jourdan T; Kessler, David M; Noble, Jack H; Gifford, René H; Labadie, Robert F

2018-06-01

To quantify and compare the number of cochlear implant (CI) electrodes found to be extracochlear on postoperative computerized tomography (CT) scans, the number of basal electrodes deactivated during standard CI mapping (without knowledge of the postoperative CT scan), and the extent of electrode insertion noted by the surgeon. Retrospective. Academic Medical Center. Two hundred sixty-two patients underwent standard cochlear implantation and postoperative temporal bone CT scanning. Scans were analyzed to determine the number of extracochlear electrodes. Standard CI programming had been completed without knowledge of the extracochlear electrodes identified on the CT. These standard CI maps were reviewed to record the number of deactivated basal electrodes. Lastly, each operative report was reviewed to record the extent of reported electrode insertion. 13.4% (n = 35) of CIs were found to have at least one electrode outside of the cochlea on the CT scan. Review of CI mapping indicated that audiologists had deactivated extracochlear electrodes in 60% (21) of these cases. Review of operative reports revealed that surgeons correctly indicated the number of extracochlear electrodes in 6% (2) of these cases. Extracochlear electrodes were correctly identified audiologically in 60% of cases and in surgical reports in 6% of cases; however, it is possible that at least a portion of these cases involved postoperative electrode migration. Given these findings, postoperative CT scans can provide information regarding basal electrode location, which could help improve programming accuracy, associated frequency allocation, and audibility with appropriate deactivation of extracochlear electrodes.

Evaluation of in-vivo measurement errors associated with micro-computed tomography scans by means of the bone surface distance approach.

PubMed

Lu, Yongtao; Boudiffa, Maya; Dall'Ara, Enrico; Bellantuono, Ilaria; Viceconti, Marco

2015-11-01

In vivo micro-computed tomography (µCT) scanning is an important tool for longitudinal monitoring of the bone adaptation process in animal models. However, the errors associated with the usage of in vivo µCT measurements for the evaluation of bone adaptations remain unclear. The aim of this study was to evaluate the measurement errors using the bone surface distance approach. The right tibiae of eight 14-week-old C57BL/6 J female mice were consecutively scanned four times in an in vivo µCT scanner using a nominal isotropic image voxel size (10.4 µm) and the tibiae were repositioned between each scan. The repeated scan image datasets were aligned to the corresponding baseline (first) scan image dataset using rigid registration and a region of interest was selected in the proximal tibia metaphysis for analysis. The bone surface distances between the repeated and the baseline scan datasets were evaluated. It was found that the average (±standard deviation) median and 95th percentile bone surface distances were 3.10 ± 0.76 µm and 9.58 ± 1.70 µm, respectively. This study indicated that there were inevitable errors associated with the in vivo µCT measurements of bone microarchitecture and these errors should be taken into account for a better interpretation of bone adaptations measured with in vivo µCT. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Internal log scanning: Research to reality

Treesearch

Daniel L. Schmoldt

2000-01-01

Improved log breakdown into lumber has been an active research topic since the 1960's. Demonstrated economic gains have driven the search for a cost-effective method to scan logs internally, from which it is assumed one can chose a better breakdown strategy. X-ray computed tomography (CT) has been widely accepted as the most promising internal imaging technique....

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…

Late-onset Pneumocystis jirovecii pneumonia post-fludarabine, cyclophosphamide and rituximab: implications for prophylaxis.

PubMed

Haeusler, Gabrielle M; Slavin, Monica A; Seymour, John F; Lingaratnam, Senthil; Teh, Benjamin W; Tam, Constantine S; Thursky, Karin A; Worth, Leon J

2013-08-01

Fludarabine, cyclophosphamide and rituximab (FCR) therapy for lymphoid malignancies has historically been associated with a low reported incidence of Pneumocystis jirovecii pneumonia (PJP). However, prophylaxis was routinely used in early studies, and molecular diagnostic tools were not employed. The objective of this study was to review the incidence of PJP during and post-FCR in the era of highly sensitive molecular diagnostics and (18) F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computerised tomography (CT). All patients treated with standard FCR at the Peter MacCallum Cancer Centre (March 2009 to June 2012) were identified from a medications management database. Laboratory-confirmed PJP cases during this time were identified from an electronic database. Overall, 66 patients were treated with a median of 5.5 FCR cycles. Eight PJP cases were identified, 6 of whom had received chemotherapy prior to FCR. In 5 cases, (18) F-FDG PET demonstrated bilateral ground-glass infiltrates. Median CD4(+) lymphocyte counts at time of PJP diagnosis and 9-12 months following FCR were 123 and 400 cells/μL, respectively. In patients receiving no prophylaxis, 9.1% developed PJP during FCR. The rate following FCR was 18.4%, with median onset at 6 months (2.4-24 months). Given the high rate of late-onset PJP, consideration should be given for extended PJP prophylaxis for up to 12 months post-FCR, particularly in pretreated patients. Further evaluation of the role of CD4(+) monitoring is warranted to quantify risk of disease development and to guide duration of prophylaxis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Impaired dopaminergic neurotransmission in patients with traumatic brain injury: a SPECT study using 123I-beta-CIT and 123I-IBZM.

PubMed

Donnemiller, E; Brenneis, C; Wissel, J; Scherfler, C; Poewe, W; Riccabona, G; Wenning, G K

2000-09-01

Structural imaging suggests that traumatic brain injury (TBI) may be associated with disruption of neuronal networks, including the nigrostriatal dopaminergic pathway. However, to date deficits in pre- and/or postsynaptic dopaminergic neurotransmission have not been demonstrated in TBI using functional imaging. We therefore assessed dopaminergic function in ten TBI patients using [123I]2-beta-carbomethoxy-3-beta-(4-iodophenyl)tropane (beta-CIT) and [123I]iodobenzamide (IBZM) single-photon emission tomography (SPET). Average Glasgow Coma Scale score (+/-SD) at the time of head trauma was 5.8+/-4.2. SPET was performed on average 141 days (SD +/-92) after TBI. The SPET images were compared with structural images using cranial computerised tomography (CCT) and magnetic resonance imaging (MRI). SPET was performed with an ADAC Vertex dual-head camera. The activity ratios of striatal to cerebellar uptake were used as a semiquantitative parameter of striatal dopamine transporter (DAT) and D2 receptor (D2R) binding. Compared with age-matched controls, patients with TBI had significantly lower striatal/cerebellar beta-CIT and IBZM binding ratios (P< or =0.01). Overall, the DAT deficit was more marked than the D2R loss. CCT and MRI studies revealed varying cortical and subcortical lesions, with the frontal lobe being most frequently affected whereas the striatum appeared structurally normal in all but one patient. Our findings suggest that nigrostriatal dysfunction may be detected using SPET following TBI despite relative structural preservation of the striatum. Further investigations of possible clinical correlates and efficacy of dopaminergic therapy in patients with TBI seem justified.

PATTERN OF INTERSTITIAL LUNG DISEASE AS SEEN BY HIGH RESOLUTION COMPUTERISED TOMOGRAPHY.

PubMed

Onyambu, C K; Waigwa, M N

2012-09-01

Diffuse lung diseases constitute a major cause of morbidity and mortality worldwide. High Resolution Computed Tomography (HRCT) is the recommended imaging technique in the diagnosis, assessment and followup of these diseases. To describe the pattern of HRCT findings in patients with suspected interstitial lung disease. Kenyatta National Hospital (KNH), Nairobi Hospital and MP Shah Hospital; all situated in Nairobi, during the period February to August 2010. One hundred and one patients sent for HRCT in the six month study period. A total of 101 patients were recruited with age range 18 to 100 years, with a mean age of 53.6 (SD 19.7) years and a median age of 54 years. The male-female ratio was 1.2:1. Cough [80.2% (n = 81)] was the most common presenting complaint followed by dyspnoea (53.5%, n = 53) and chest pain [24.8% (n = 25)]. Overall, the predominant pattern of involvement on chest HRCT was reticular pattern seen in 56.1% (n = 82) of patients, followed by honey-comb pattern (37.8%, n = 82). The study demonstrated marked lung parenchymal destruction in most cases; a poor prognostic indicator which could have been due to delayed referral. HRCT has a high pick up rate of subtle parenchymal lung lesions as well as defining the lesions and their distribution compared to plain chest radiography. This is important in narrowing the differential diagnosis as well as for pre-biopsy planning. The diagnosis of ILD requires a multidisciplinary approach including a detailed clinical history, physical findings, and laboratory investigations, radiological and histological assessment.

Prediction of Blood-Brain Barrier Disruption and Intracerebral Hemorrhagic Infarction Using Arterial Spin-Labeling Magnetic Resonance Imaging.

PubMed

Niibo, Takeya; Ohta, Hajime; Miyata, Shirou; Ikushima, Ichiro; Yonenaga, Kazuchika; Takeshima, Hideo

2017-01-01

Arterial spin-labeling magnetic resonance imaging is sensitive for detecting hyperemic lesions (HLs) in patients with acute ischemic stroke. We evaluated whether HLs could predict blood-brain barrier (BBB) disruption and hemorrhagic transformation (HT) in acute ischemic stroke patients. In a retrospective study, arterial spin-labeling was performed within 6 hours of symptom onset before revascularization treatment in 25 patients with anterior circulation large vessel occlusion on baseline magnetic resonance angiography. All patients underwent angiographic procedures intended for endovascular therapy and a noncontrast computed tomography scan immediately after treatment. BBB disruption was defined as a hyperdense lesion present on the posttreatment computed tomography scan. A subacute magnetic resonance imaging or computed tomography scan was performed during the subacute phase to assess HTs. The relationship between HLs and BBB disruption and HT was examined using the Alberta Stroke Program Early Computed Tomography Score locations in the symptomatic hemispheres. A HL was defined as a region where CBF relative ≥1.4 (CBF relative =CBF HL /CBF contralateral ). HLs, BBB disruption, and HT were found in 9, 15, and 15 patients, respectively. Compared with the patients without HLs, the patients with HLs had a higher incidence of both BBB disruption (100% versus 37.5%; P=0.003) and HT (100% versus 37.5%; P=0.003). Based on the Alberta Stroke Program Early Computed Tomography Score locations, 21 regions of interests displayed HLs. Compared with the regions of interests without HLs, the regions of interests with HLs had a higher incidence of both BBB disruption (42.8% versus 3.9%; P<0.001) and HT (85.7% versus 7.8%; P<0.001). HLs detected on pretreatment arterial spin-labeling maps may enable the prediction and localization of subsequent BBB disruption and HT. © 2016 American Heart Association, Inc.

Dynamic in vivo imaging of small animal brain using pulsed laser diode-based photoacoustic tomography system

NASA Astrophysics Data System (ADS)

Upputuri, Paul Kumar; Pramanik, Manojit

2017-09-01

We demonstrate dynamic in vivo imaging using a low-cost portable pulsed laser diode (PLD)-based photoacoustic tomography system. The system takes advantage of an 803-nm PLD having high-repetition rate ˜7000 Hz combined with a fast-scanning single-element ultrasound transducer leading to a 5 s cross-sectional imaging. Cortical vasculature is imaged in scan time of 5 s with high signal-to-noise ratio ˜48. To examine the ability for dynamic imaging, we monitored the fast uptake and clearance process of indocyanine green in the rat brain. The system will find applications to study neurofunctional activities, characterization of pharmacokinetic, and biodistribution profiles in the development process of drugs or imaging agents.

Quantitative, simultaneous, and collinear eye-tracked, high dynamic range optical coherence tomography at 850 and 1060 nm

NASA Astrophysics Data System (ADS)

Mooser, Matthias; Burri, Christian; Stoller, Markus; Luggen, David; Peyer, Michael; Arnold, Patrik; Meier, Christoph; Považay, Boris

2017-07-01

Ocular optical coherence tomography at the wavelengths ranges of 850 and 1060 nm have been integrated with a confocal scanning laser ophthalmoscope eye-tracker as a clinical commercial-class system. Collinear optics enables an exact overlap of the different channels to produce precisely overlapping depth-scans for evaluating the similarities and differences between the wavelengths to extract additional physiologic information. A reliable segmentation algorithm utilizing Graphcuts has been implemented and applied to automatically extract retinal and choroidal shape in cross-sections and volumes. The device has been tested in normals and pathologies including a cross-sectional and longitudinal study of myopia progress and control with a duplicate instrument in Asian children.

Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update.

PubMed

Zhang, Bing; Li, Ni; Kang, Jie; He, Yi; Chen, Xiao-Ming

2017-01-01

Adaptive optics scanning laser ophthalmoscopy (AO-SLO) has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics (AO) and AO-SLO. Then it compares AO-SLO with conventional imaging methods (fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography) and other AO techniques (adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherence tomography). Furthermore, an update of current research situation in AO-SLO is made based on different fundus structures as photoreceptors (cones and rods), fundus vessels, retinal pigment epithelium layer, retinal nerve fiber layer, ganglion cell layer and lamina cribrosa. Finally, this review indicates possible research directions of AO-SLO in future.

Occult fractures of the knee: tomographic evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apple, J.S.; Martinez, S.; Allen, N.B.

1983-08-01

Seven adults with painful effusions of the knee were examined for occult fractures using pluridirectional tomograph in the coronal and lateral planes. Six patients (ages 50 to 82 years) were osteopenic and gave histories ranging from none to mild trauma; one 26-year-old man was not osteopenic and had severe trauma. In all cases, routine radiographs were interpreted as negative, but tomography demonstrated a fracture. Five fractures were subchondral. Bone scans in 2 patients were positive. The authors conclude that osteopenic patients with a painful effusion of the knee should be considered to have an occult fracture. While bone scans maymore » be helpful, tomography is recommended as the procedure of choice to define the location and extent of the fracture.« less

Numerical dispersion compensation for Partial Coherence Interferometry and Optical Coherence Tomography.

PubMed

Fercher, A; Hitzenberger, C; Sticker, M; Zawadzki, R; Karamata, B; Lasser, T

2001-12-03

Dispersive samples introduce a wavelength dependent phase distortion to the probe beam. This leads to a noticeable loss of depth resolution in high resolution OCT using broadband light sources. The standard technique to avoid this consequence is to balance the dispersion of the sample byarrangingadispersive materialinthereference arm. However, the impact of dispersion is depth dependent. A corresponding depth dependent dispersion balancing technique is diffcult to implement. Here we present a numerical dispersion compensation technique for Partial Coherence Interferometry (PCI) and Optical Coherence Tomography (OCT) based on numerical correlation of the depth scan signal with a depth variant kernel. It can be used a posteriori and provides depth dependent dispersion compensation. Examples of dispersion compensated depth scan signals obtained from microscope cover glasses are presented.

Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update

PubMed Central

Zhang, Bing; Li, Ni; Kang, Jie; He, Yi; Chen, Xiao-Ming

2017-01-01

Adaptive optics scanning laser ophthalmoscopy (AO-SLO) has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics (AO) and AO-SLO. Then it compares AO-SLO with conventional imaging methods (fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography) and other AO techniques (adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherence tomography). Furthermore, an update of current research situation in AO-SLO is made based on different fundus structures as photoreceptors (cones and rods), fundus vessels, retinal pigment epithelium layer, retinal nerve fiber layer, ganglion cell layer and lamina cribrosa. Finally, this review indicates possible research directions of AO-SLO in future. PMID:29181321

Three-dimensional monochromatic x-ray computed tomography using synchrotron radiation

NASA Astrophysics Data System (ADS)

Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Katsuyuki; Uyama, Chikao

1998-08-01

We describe a technique of 3D computed tomography (3D CT) using monochromatic x rays generated by synchrotron radiation, which performs a direct reconstruction of a 3D volume image of an object from its cone-beam projections. For the development, we propose a practical scanning orbit of the x-ray source to obtain complete 3D information on an object, and its corresponding 3D image reconstruction algorithm. The validity and usefulness of the proposed scanning orbit and reconstruction algorithm were confirmed by computer simulation studies. Based on these investigations, we have developed a prototype 3D monochromatic x-ray CT using synchrotron radiation, which provides exact 3D reconstruction and material-selective imaging by using the K-edge energy subtraction technique.

18F-fluorodeoxyglucose-positron emission tomography scanning is more useful in followup than in the initial assessment of patients with Erdheim-Chester disease.

PubMed

Arnaud, Laurent; Malek, Zoulikha; Archambaud, Frédérique; Kas, Aurélie; Toledano, Dan; Drier, Aurélie; Zeitoun, Delphine; Cluzel, Philippe; Grenier, Philippe A; Chiras, Jacques; Piette, Jean-Charles; Amoura, Zahir; Haroche, Julien

2009-10-01

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans' cell histiocytosis. The aim of this study was to assess the value of whole-body scanning with (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) in a large cohort of ECD patients from a single center. We retrospectively reviewed all PET scans performed on 31 patients with ECD who were referred to our department between 2005 and 2008. PET images were reviewed by 2 independent nuclear medicine specialist physicians and were compared with other imaging modalities performed within 15 days of each PET scan. Thirty-one patients (10 women and 21 men; median age 59.5 years) underwent a total of 65 PET scans. Twenty-three patients (74%) were untreated at the time of the initial PET scan, whereas 30 of the 34 followup PET scans (88%) were performed in patients who were undergoing immunomodulatory therapy. Comparison of the initial and followup PET scans with other imaging modalities revealed that the sensitivity of PET scanning varied greatly among the different organs studied (range 4.3-100%), while the specificity remained high (range 69.2-100%). Followup PET scans were particularly helpful in assessing central nervous system (CNS) involvement, since the PET scan was able to detect an early therapeutic response of CNS lesions, even before magnetic resonance imaging showed a decrease in their size. PET scanning was also very helpful in evaluating the cardiovascular system, which is a major prognostic factor in ECD, by assessing the heart and the entire vascular tree during a single session. The results of our large, single-center, retrospective study suggest that the findings of a FDG-PET scan may be interesting in the initial assessment of patients with ECD, but its greater contribution is in followup of these patients.

Optical Coherence Tomography (OCT) Device Independent Intraretinal Layer Segmentation

PubMed Central

Ehnes, Alexander; Wenner, Yaroslava; Friedburg, Christoph; Preising, Markus N.; Bowl, Wadim; Sekundo, Walter; zu Bexten, Erdmuthe Meyer; Stieger, Knut; Lorenz, Birgit

2014-01-01

Purpose To develop and test an algorithm to segment intraretinal layers irrespectively of the actual Optical Coherence Tomography (OCT) device used. Methods The developed algorithm is based on the graph theory optimization. The algorithm's performance was evaluated against that of three expert graders for unsigned boundary position difference and thickness measurement of a retinal layer group in 50 and 41 B-scans, respectively. Reproducibility of the algorithm was tested in 30 C-scans of 10 healthy subjects each with the Spectralis and the Stratus OCT. Comparability between different devices was evaluated in 84 C-scans (volume or radial scans) obtained from 21 healthy subjects, two scans per subject with the Spectralis OCT, and one scan per subject each with the Stratus OCT and the RTVue-100 OCT. Each C-scan was segmented and the mean thickness for each retinal layer in sections of the early treatment of diabetic retinopathy study (ETDRS) grid was measured. Results The algorithm was able to segment up to 11 intraretinal layers. Measurements with the algorithm were within the 95% confidence interval of a single grader and the difference was smaller than the interindividual difference between the expert graders themselves. The cross-device examination of ETDRS-grid related layer thicknesses highly agreed between the three OCT devices. The algorithm correctly segmented a C-scan of a patient with X-linked retinitis pigmentosa. Conclusions The segmentation software provides device-independent, reliable, and reproducible analysis of intraretinal layers, similar to what is obtained from expert graders. Translational Relevance Potential application of the software includes routine clinical practice and multicenter clinical trials. PMID:24820053

Advantages and limitations of computed tomography scans for treatment planning of lung cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mira, J.G.; Potter, J.L.; Fullerton, G.D.

1982-09-01

Forty-five Chest computed tomography (CT) scans performed on patients with lung carcinoma (LC) were evaluated in an attempt to understand the pattern of intrathoracic tumor spread and the advantages and limitations this technique offers for treatment planning when compared to planning done by conventional X rays. The following findings can help treatment planning. (1) When regular X rays do not show location (i.e., hemithorax opacification), CT scan will show it in 68% of patients. If regular X rays show a well localized mass, unsuspected tumor extensions were disclosed in 78% of these patients. Hence, CT scans should be done inmore » all LC patients prior to treatment planning; (2) Mediastinal masses frequently spread anteriorly toward the sternum and posteriorly around the vertebral bodies toward the cord and costal pleura. This should be considered for radiotherapy boost techniques; (3) Lung masses spread in one third of cases toward the lateral costal pleura. Thus, the usual 1-2cm of safety margin around the LC are not sufficient in some cases; (4) Tumor size can appear much smaller in regular X rays than in CT scans. Hence, CT scans are necessary for accurate staging and evaluation of tumor response. Some CT scan limitations are: (1) Atelectasis blends with tumor in approximately half of the patients, thus obscuring tumor boundaries; (2) CT numbers and contrast enhancement did not help to differentiate between these two structures; and (3) Limited definition of CT scan prevents investigation of suspected microscopic spread around tumor masses.« less

Evaluation of variations in absorbed dose and image noise according to patient forms in X-ray computed tomography.

PubMed

Matsubara, Kosuke; Koshida, Kichiro; Suzuki, Masayuki; Hayakawa, Mayumi; Tsujii, Hideo; Yamamoto, Tomoyuki

2005-12-20

Excessive radiation exposure in pediatric computed tomography (CT) scanning has become a serious problem, and it is difficult to select scan parameters for the scanning of small patients such as children. We investigated differences in absorbed dose and standard deviation (SD) in Hounsfield unit (HU) caused by differences in the form of the subject using a body-type phantom with removable body parts. Using four X-ray CT scanners, measurements were made with values from 50 mAs to 300 mAs, with slices of 50 mAs, using scan protocols that were assumed to perform thorough examinations. The results showed that the mAs values and absorbed doses were almost proportional, and the absorbed doses in the phantom without body parts were about 1.1-2.2-fold higher than those of the phantom with body parts at the same points. The SD values obtained indicated that the absorbed doses in the phantom with body parts were 0.3-0.6 times those of the phantom without body parts when the mAs values used were adjusted so that both SD values were the same. The absorbed doses in various patient forms can be estimated from these results, and they will become critical data for the selection of appropriate scan protocols.

Prevalence and correlates of patient-centred preparatory information provision to computed tomography and magnetic resonance imaging outpatients: A cross-sectional study.

PubMed

Hyde, Lisa; Mackenzie, Lisa; Boyes, Allison W; Evans, Tiffany-Jane; Symonds, Michael; Sanson-Fisher, Rob

2018-06-02

Responsiveness to information preferences is key to high-quality, patient-centred care. This study examined the top ten preparatory information items not delivered in accordance with medical imaging outpatients' preferences, and patient characteristics associated with reporting a greater number of unmet information preferences. Magnetic resonance imaging and computed tomography outpatients were recruited consecutively in one major public hospital waiting room. Participants self-administered a touchscreen computer questionnaire assessing their sociodemographic and scan characteristics, and unmet preferences for 33 guideline-endorsed preparatory information items. Of 317 eligible patients, 280 (88%) consented to participate. Given equal rankings, the top ten unmet information preferences included 13 items which were endorsed by at least 25% of participants, and commonly related to receiving 'too little' information. One item related to the pre-scan period, seven items to the scan period and five items to the post-scan period. None of the patient characteristics examined were significantly associated with reporting a greater number of unmet information preferences. There is room to improve responsiveness to medical imaging outpatients' preparatory information preferences. Improvements should be targeted at individuals, rather than groups defined by sociodemographic or scan characteristics. A standardised approach to addressing individual patient's information preferences is needed. Copyright © 2018 Elsevier B.V. All rights reserved.

Volumetric imaging of rod and cone photoreceptor structure with a combined adaptive optics-optical coherence tomography-scanning laser ophthalmoscope

NASA Astrophysics Data System (ADS)

Wells-Gray, Elaine M.; Choi, Stacey S.; Zawadzki, Robert J.; Finn, Susanna C.; Greiner, Cherry; Werner, John S.; Doble, Nathan

2018-03-01

We have designed and implemented a dual-mode adaptive optics (AO) imaging system that combines spectral domain optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) for in vivo imaging of the human retina. The system simultaneously acquires SLO frames and OCT B-scans at 60 Hz with an OCT volume acquisition time of 4.2 s. Transverse eye motion measured from the SLO is used to register the OCT B-scans to generate three-dimensional (3-D) volumes. Key optical design considerations include: minimizing system aberrations through the use of off-axis relay telescopes, conjugate pupil plane requirements, and the use of dichroic beam splitters to separate and recombine the OCT and SLO beams around the nonshared horizontal scanning mirrors. To demonstrate system performance, AO-OCT-SLO images and measurements are taken from three normal human subjects ranging in retinal eccentricity from the fovea out to 15-deg temporal and 20-deg superior. Also presented are en face OCT projections generated from the registered 3-D volumes. The ability to acquire high-resolution 3-D images of the human retina in the midperiphery and beyond has clinical importance in diseases, such as retinitis pigmentosa and cone-rod dystrophy.

Volume adjustment of lung density by computed tomography scans in patients with emphysema.

PubMed

Shaker, S B; Dirksen, A; Laursen, L C; Skovgaard, L T; Holstein-Rathlou, N H

2004-07-01

To determine how to adjust lung density measurements for the volume of the lung calculated from computed tomography (CT) scans in patients with emphysema. Fifty patients with emphysema underwent 3 CT scans at 2-week intervals. The scans were analyzed with a software package that detected the lung in contiguous images and subsequently generated a histogram of the pixel attenuation values. The total lung volume (TLV), lung weight, percentile density (PD), and relative area of emphysema (RA) were calculated from this histogram. RA and PD are commonly applied measures of pulmonary emphysema derived from CT scans. These parameters are markedly influenced by changes in the level of inspiration. The variability of lung density due to within-subject variation in TLV was explored by plotting TLV against PD and RA. The coefficients for volume adjustment for PD were relatively stable over a wide range from the 10th to the 80th percentile, whereas for RA the coefficients showed large variability especially in the lower range, which is the most relevant for quantitation of pulmonary emphysema. Volume adjustment is mandatory in repeated CT densitometry and is more robust for PD than for RA. Therefore, PD seems more suitable for monitoring the progression of emphysema.

Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography

PubMed Central

Periyasamy, M.; Dhanasekaran, R.

2014-01-01

The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning. PMID:24701187

Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography.

PubMed

Li, Qian; Li, Lin; Fan, Shanhui; Dai, Cuixia; Chai, Xinyu; Zhou, Chuanqing

2018-02-01

The human eyes provide a natural window for noninvasive measurement of the pulse wave velocity (PWV) of small arteries. By measuring the retinal PWV, the stiffness of small arteries can be assessed, which may better detect early vascular diseases. Therefore, retinal PWV measurement has attracted increasing attention. In this study, a jump-scanning method was proposed for noninvasive measurement of retinal PWV using spectral-domain optical coherence tomography (SD-OCT). The jump-scanning method uses the phase-resolved Doppler OCT to obtain the pulse shapes. To realize PWV measurement, the jump-scanning method extracts the transit time of the pulse wave from an original OCT scanning site to another through a transient jump. The measured retinal arterial PWV of a young human subject with normal blood pressure was in the order of 20 to 30 mm/s, which was consistent with previous studies. As a comparison, PWV of 50 mm/s was measured for a young human subject with prehypertension, which was in accordance with the finding of strong association between retinal PWV and blood pressure. In summary, it is believed the proposed jump-scanning method could benefit the research and diagnosis of vascular diseases through the window of human eyes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterizing the localized surface plasmon resonance behaviors of Au nanorings and tracking their diffusion in bio-tissue with optical coherence tomography

PubMed Central

Lee, Cheng-Kuang; Tseng, Hung-Yu; Lee, Chia-Yun; Wu, Shou-Yen; Chi, Ting-Ta; Yang, Kai-Min; Chou, Han-Yi Elizabeth; Tsai, Meng-Tsan; Wang, Jyh-Yang; Kiang, Yean-Woei; Chiang, Chun-Pin; Yang, C. C.

2010-01-01

The characterization results of the localized surface plasmon resonance (LSPR) of Au nanorings (NRs) with optical coherence tomography (OCT) are first demonstrated. Then, the diffusion behaviors of Au NRs in mouse liver samples tracked with OCT are shown. For such research, aqueous solutions of Au NRs with two different localized surface plasmon resonance (LSPR) wavelengths are prepared and characterized. Their LSPR-induced extinction cross sections at 1310 nm are estimated with OCT scanning of solution droplets on coverslip to show reasonably consistent results with the data at individual LSPR wavelengths and at 1310 nm obtained from transmission measurements of Au NR solutions and numerical simulations. The resonant and non-resonant Au NRs are delivered into mouse liver samples for tracking Au NR diffusion in the samples through continuous OCT scanning for one hour. With resonant Au NRs, the average A-mode scan profiles of OCT scanning at different delay times clearly demonstrate the extension of strong backscattering depth with time. The calculation of speckle variance among successive OCT scanning images, which is related to the local transport speed of Au NRs, leads to the illustrations of downward propagation and spreading of major Au NR motion spot with time. PMID:21258530

Four-Dimensional Positron Emission Tomography: Implications for Dose Painting of High-Uptake Regions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aristophanous, Michalis, E-mail: maristophanous@lroc.harvard.edu; Yap, Jeffrey T.; Killoran, Joseph H.

Purpose: To investigate the behavior of tumor subvolumes of high [18F]-fluorodeoxyglucose (FDG) uptake as seen on clinical four-dimensional (4D) FDG-positron emission tomography (PET) scans. Methods and Materials: Four-dimensional FDG-PET/computed tomography scans from 13 patients taken before radiotherapy were available. The analysis was focused on regions of high uptake that are potential dose-painting targets. A total of 17 lesions (primary tumors and lymph nodes) were analyzed. On each one of the five phases of the 4D scan a classification algorithm was applied to obtain the region of highest uptake and segment the tumor volume. We looked at the behavior of bothmore » the high-uptake subvolume, called 'Boost,' and the segmented tumor volume, called 'Target.' We measured several quantities that characterize the Target and Boost volumes and quantified correlations between them. Results: The behavior of the Target could not always predict the behavior of the Boost. The shape deformation of the Boost regions was on average 133% higher than that of the Target. The gross to internal target volume expansion was on average 27.4% for the Target and 64% for the Boost, a statistically significant difference (p < 0.05). Finally, the inhale-to-exhale phase (20%) had the highest shape deformation for the Boost regions. Conclusions: A complex relationship between the measured quantities for the Boost and Target volumes is revealed. The results suggest that in cases in which advanced therapy techniques such as dose painting are being used, a close examination of the 4D PET scan should be performed.« less

Computerised pathology test order entry reduces laboratory turnaround times and influences tests ordered by hospital clinicians: a controlled before and after study

PubMed Central

Westbrook, J I; Georgiou, A; Dimos, A; Germanos, T

2006-01-01

Objective To assess the impact of a computerised pathology order entry system on laboratory turnaround times and test ordering within a teaching hospital. Methods A controlled before and after study compared test assays ordered from 11 wards two months before (n = 97 851) and after (n = 113 762) the implementation of a computerised pathology order entry system (Cerner Millennium Powerchart). Comparisons were made of laboratory turnaround times, frequency of tests ordered and specimens taken, proportions of patients having tests, average number per patient, and percentage of gentamicin and vancomycin specimens labelled as random. Results Intervention wards experienced an average decrease in turnaround of 15.5 minutes/test assay (range 73.8 to 58.3 minutes; p<0.001). Reductions were significant for prioritised and non‐prioritised tests, and for those done within and outside business hours. There was no significant change in the average number of tests (p = 0.228), or specimens per patient (p = 0.324), and no change in turnaround time for the control ward (p = 0.218). Use of structured order screens enhanced data provided to laboratories. Removing three test assays from the liver function order set resulted in significantly fewer of these tests being done. Conclusions Computerised order entry systems are an important element in achieving faster test results. These systems can influence test ordering patterns through structured order screens, manipulation of order sets, and analysis of real time data to assess the impact of such changes, not possible with paper based systems. The extent to which improvements translate into improved patient outcomes remains to be determined. A potentially limiting factor is clinicians' capacity to respond to, and make use of, faster test results. PMID:16461564

Practices to prevent venous thromboembolism: a brief review

PubMed Central

Lau, Brandyn D; Haut, Elliott R

2014-01-01

Background Venous thromboembolism (VTE) is a common cause of preventable harm for hospitalised patients. Over the past decade, numerous intervention types have been implemented in attempts to improve the prescription of VTE prophylaxis in hospitals, with varying degrees of success. We reviewed key articles to assess the efficacy of different types of interventions to improve prescription of VTE prophylaxis for hospitalised patients. Methods We conducted a search of MEDLINE for key studies published between 2001 and 2012 of interventions employing education, paper based tools, computerised tools, real time audit and feedback, or combinations of intervention types to improve prescription of VTE prophylaxis for patients in hospital settings. Process outcomes of interest were prescription of any VTE prophylaxis and best practice VTE prophylaxis. Clinical outcomes of interest were any VTE and potentially preventable VTE, defined as VTE occurring in patients not prescribed appropriate prophylaxis. Results 16 articles were included in this review. Two studies employed education only, four implemented paper based tools, four used computerised tools, two evaluated audit and feedback strategies, and four studies used combinations of intervention types. Individual modalities result in improved prescription of VTE prophylaxis; however, the greatest and most sustained improvements were those that combined education with computerised tools. Conclusions Many intervention types have proven effective to different degrees in improving VTE prevention. Provider education is likely a required additional component and should be combined with other intervention types. Active mandatory tools are likely more effective than passive ones. Information technology tools that are well integrated into provider workflow, such as alerts and computerised clinical decision support, can improve best practice prophylaxis use and prevent patient harm resulting from VTE. PMID:23708438

Lessons from the Johns Hopkins Multi-Disciplinary Venous Thromboembolism (VTE) Prevention Collaborative

PubMed Central

Streiff, Michael B; Carolan, Howard T; Hobson, Deborah B; Kraus, Peggy S; Holzmueller, Christine G; Demski, Renee; Lau, Brandyn D; Biscup-Horn, Paula; Pronovost, Peter J

2012-01-01

Problem Venous thromboembolism (VTE) is a common cause of potentially preventable mortality, morbidity, and increased medical costs. Risk-appropriate prophylaxis can prevent most VTE events, but only a small fraction of patients at risk receive this treatment. Design Prospective quality improvement programme. Setting Johns Hopkins Hospital, Baltimore, Maryland, USA. Strategies for change A multidisciplinary team established a VTE Prevention Collaborative in 2005. The collaborative applied the four step TRIP (translating research into practice) model to develop and implement a mandatory clinical decision support tool for VTE risk stratification and risk-appropriate VTE prophylaxis for all hospitalised adult patients. Initially, paper based VTE order sets were implemented, which were then converted into 16 specialty-specific, mandatory, computerised, clinical decision support modules. Key measures for improvement VTE risk stratification within 24 hours of hospital admission and provision of risk-appropriate, evidence based VTE prophylaxis. Effects of change The VTE team was able to increase VTE risk assessment and ordering of risk-appropriate prophylaxis with paper based order sets to a limited extent, but achieved higher compliance with a computerised clinical decision support tool and the data feedback which it enabled. Risk-appropriate VTE prophylaxis increased from 26% to 80% for surgical patients and from 25% to 92% for medical patients in 2011. Lessons learnt A computerised clinical decision support tool can increase VTE risk stratification and risk-appropriate VTE prophylaxis among hospitalised adult patients admitted to a large urban academic medical centre. It is important to ensure the tool is part of the clinician’s normal workflow, is mandatory (computerised forcing function), and offers the requisite modules needed for every clinical specialty. PMID:22718994

Linear-array based full-view high-resolution photoacoustic computed tomography of whole mouse brain functions in vivo

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Pengfei; Wang, Lihong V.

2018-02-01

Photoacoustic computed tomography (PACT) is a non-invasive imaging technique offering high contrast, high resolution, and deep penetration in biological tissues. We report a photoacoustic computed tomography (PACT) system equipped with a high frequency linear array for anatomical and functional imaging of the mouse whole brain. The linear array was rotationally scanned in the coronal plane to achieve the full-view coverage. We investigated spontaneous neural activities in the deep brain by monitoring the hemodynamics and observed strong interhemispherical correlations between contralateral regions, both in the cortical layer and in the deep regions.

Repeated irradiation from micro-computed tomography scanning at 2, 4 and 6 months of age does not induce damage to tibial bone microstructure in male and female CD-1 mice.

PubMed

Sacco, Sandra M; Saint, Caitlin; Longo, Amanda B; Wakefield, Charles B; Salmon, Phil L; LeBlanc, Paul J; Ward, Wendy E

2017-01-01

Long-term effects of repeated i n vivo micro-computed tomography (μCT) scanning at key stages of growth and bone development (ages 2, 4 and 6 months) on trabecular and cortical bone structure, as well as developmental patterns, have not been studied. We determined the effect of repetitive μCT scanning at age 2, 4 and 6 months on tibia bone structure of male and female CD-1 mice and characterized developmental changes. At 2, 4 and 6 months of age, right tibias were scanned using in vivo μCT (Skyscan 1176) at one of three doses of radiation per scan: 222, 261 or 460 mGy. Left tibias of the same mice were scanned only at 6 months to serve as non-irradiated controls to determine whether recurrent radiation exposure alters trabecular and cortical bone structure at the proximal tibia. In males, eccentricity was lower ( P <0.05) in irradiated compared with non-irradiated tibias (222 mGy group). Within each sex, all other structural outcomes were similar between irradiated and non-irradiated tibias regardless of dose. Trabecular bone loss occurred in all mice due to age while cortical development continued to age 6 months. In conclusion, repetitive μCT scans at various radiation doses did not damage trabecular or cortical bone structure of proximal tibia in male and female CD-1 mice. Moreover, scanning at 2, 4 and 6 months of age highlight the different developmental time course between trabecular and cortical bone. These scanning protocols can be used to investigate longitudinal responses of bone structures to an intervention.

Automatic segmentation in three-dimensional analysis of fibrovascular pigmentepithelial detachment using high-definition optical coherence tomography.

PubMed

Ahlers, C; Simader, C; Geitzenauer, W; Stock, G; Stetson, P; Dastmalchi, S; Schmidt-Erfurth, U

2008-02-01

A limited number of scans compromise conventional optical coherence tomography (OCT) to track chorioretinal disease in its full extension. Failures in edge-detection algorithms falsify the results of retinal mapping even further. High-definition-OCT (HD-OCT) is based on raster scanning and was used to visualise the localisation and volume of intra- and sub-pigment-epithelial (RPE) changes in fibrovascular pigment epithelial detachments (fPED). Two different scanning patterns were evaluated. 22 eyes with fPED were imaged using a frequency-domain, high-speed prototype of the Cirrus HD-OCT. The axial resolution was 6 mum, and the scanning speed was 25 kA scans/s. Two different scanning patterns covering an area of 6 x 6 mm in the macular retina were compared. Three-dimensional topographic reconstructions and volume calculations were performed using MATLAB-based automatic segmentation software. Detailed information about layer-specific distribution of fluid accumulation and volumetric measurements can be obtained for retinal- and sub-RPE volumes. Both raster scans show a high correlation (p<0.01; R2>0.89) of measured values, that is PED volume/area, retinal volume and mean retinal thickness. Quality control of the automatic segmentation revealed reasonable results in over 90% of the examinations. Automatic segmentation allows for detailed quantitative and topographic analysis of the RPE and the overlying retina. In fPED, the 128 x 512 scanning-pattern shows mild advantages when compared with the 256 x 256 scan. Together with the ability for automatic segmentation, HD-OCT clearly improves the clinical monitoring of chorioretinal disease by adding relevant new parameters. HD-OCT is likely capable of enhancing the understanding of pathophysiology and benefits of treatment for current anti-CNV strategies in future.

Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

PubMed Central

Jornada, Tiago da Silva; da Silva, Teógenes Augusto

2014-01-01

Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

Ischemic stroke enhancement in computed tomography scans using a computational approach

NASA Astrophysics Data System (ADS)

Alves, Allan F. F.; Pavan, Ana L. M.; Jennane, Rachid; Miranda, José R. A.; Freitas, Carlos C. M.; Abdala, Nitamar; Pina, Diana R.

2018-03-01

In this work, a novel approach was proposed to enhance the visual perception of ischemic stroke in computed tomography scans. Through different image processing techniques, we enabled less experienced physicians, to reliably detect early signs of stroke. A set of 40 retrospective CT scans of patients were used, divided into two groups: 25 cases of acute ischemic stroke and 15 normal cases used as control group. All cases were obtained within 4 hours of symptoms onset. Our approach was based on the variational decomposition model and three different segmentation methods. A test determined observers' performance to correctly diagnose stroke cases. The Expectation Maximization method provided the best results among all observers. The overall sensitivity of the observer's analysis was 64% and increased to 79%. The overall specificity was 67% and increased to 78%. These results show the importance of a computational tool to assist neuroradiology decisions, especially in critical situations such as the diagnosis of ischemic stroke.

Gold Nanoparticle Quantitation by Whole Cell Tomography.

PubMed

Sanders, Aric W; Jeerage, Kavita M; Schwartz, Cindi L; Curtin, Alexandra E; Chiaramonti, Ann N

2015-12-22

Many proposed biomedical applications for engineered gold nanoparticles require their incorporation by mammalian cells in specific numbers and locations. Here, the number of gold nanoparticles inside of individual mammalian stem cells was characterized using fast focused ion beam-scanning electron microscopy based tomography. Enhanced optical microscopy was used to provide a multiscale map of the in vitro sample, which allows cells of interest to be identified within their local environment. Cells were then serially sectioned using a gallium ion beam and imaged using a scanning electron beam. To confirm the accuracy of single cross sections, nanoparticles in similar cross sections were imaged using transmission electron microscopy and scanning helium ion microscopy. Complete tomographic series were then used to count the nanoparticles inside of each cell and measure their spatial distribution. We investigated the influence of slice thickness on counting single particles and clusters as well as nanoparticle packing within clusters. For 60 nm citrate stabilized particles, the nanoparticle cluster packing volume is 2.15 ± 0.20 times the volume of the bare gold nanoparticles.

Study on internal to surface fingerprint correlation using optical coherence tomography and internal fingerprint extraction

NASA Astrophysics Data System (ADS)

Darlow, Luke Nicholas; Connan, James

2015-11-01

Surface fingerprint scanners are limited to a two-dimensional representation of the fingerprint topography, and thus, are vulnerable to fingerprint damage, distortion, and counterfeiting. Optical coherence tomography (OCT) scanners are able to image (in three dimensions) the internal structure of the fingertip skin. Techniques for obtaining the internal fingerprint from OCT scans have since been developed. This research presents an internal fingerprint extraction algorithm designed to extract high-quality internal fingerprints from touchless OCT fingertip scans. Furthermore, it serves as a correlation study between surface and internal fingerprints. Provided the scanned region contains sufficient fingerprint information, correlation to the surface topography is shown to be good (74% have true matches). The cross-correlation of internal fingerprints (96% have true matches) is substantial that internal fingerprints can constitute a fingerprint database. The internal fingerprints' performance was also compared to the performance of cropped surface counterparts, to eliminate bias owing to information level present, showing that the internal fingerprints' performance is superior 63.6% of the time.

Multiple primary malignancies of the liver and the colon: a complex diagnostic and decisional process with a final unanswered question.

PubMed

Portolani, Nazario; Baiocchi, Gianluca; Baronchelli, Carla; Gheza, Federico; Giulini, Stefano Maria

2014-03-29

We herein present the case of a 78-year-old man with an incidental finding of a solid hepatic mass without symptoms and only a laparotomic cholecystectomy for acute cholecystitis in the past surgical history. A colonoscopy, a magnetic resonance imaging scan, a positron emission tomography scan, and a computed tomography scan completed the preoperative workup: a neoplastic lesion 4.3×3 cm in size was diagnosed at segments IV and V, associated with a neoplastic involvement of the splenic flexure without signs of colonic occlusion. After colonic resection, a frozen section on a granulomatous-like tissue at gastric border suggested a diagnosis of an adenocarcinoma of bilio-pancreatic type, changing the surgical strategy to include gastric resection and hepatic pedicle node dissection. The discussion turns around the idea that a final diagnosis of colon cancer with regional nodal involvement (pT3N1) and metastatic gallbladder cancer with multiple peritoneal seedings cannot be excluded.

Anterior Eye Imaging with Optical Coherence Tomography

NASA Astrophysics Data System (ADS)

Huang, David; Li, Yan; Tang, Maolong

The development of corneal and anterior segment optical coherence tomography (OCT) technology has advanced rapidly in recently years. The scan geometry and imaging wavelength are both important choices to make in designing anterior segment OCT systems. Rectangular scan geometry offers the least image distortion and is now used in most anterior OCT systems. The wavelength of OCT light source affects resolution and penetration. An optimal choice of the OCT imaging wavelength (840, 1,050, or 1,310 nm) depends on the application of interest. Newer generation Fourier-domain OCT technology can provide scan speed 100-1000 times faster than the time-domain technology. Various commercial anterior OCT systems are available on the market. A wide spectrum of diagnostic and surgical applications using anterior segment OCT had been investigated, including mapping of corneal and epithelial thicknesses, keratoconus screening, measuring corneal refractive power, corneal surgery planning and evaluation in LASIK, intracorneal ring implantation, assessment of angle closure glaucoma, anterior chamber biometry and intraocular lens implants, intraocular lens power calculation, and eye bank donor cornea screening.

Multi-signal FIB/SEM tomography

NASA Astrophysics Data System (ADS)

Giannuzzi, Lucille A.

2012-06-01

Focused ion beam (FIB) milling coupled with scanning electron microscopy (SEM) on the same platform enables 3D microstructural analysis of structures using FIB for serial sectioning and SEM for imaging. Since FIB milling is a destructive technique, the acquisition of multiple signals from each slice is desirable. The feasibility of collecting both an inlens backscattered electron (BSE) signal and an inlens secondary electron (SE) simultaneously from a single scan of the electron beam from each FIB slice is demonstrated. The simultaneous acquisition of two different SE signals from two different detectors (inlens vs. Everhart-Thornley (ET) detector) is also possible. Obtaining multiple signals from each FIB slice with one scan increases the acquisition throughput. In addition, optimization of microstructural and morphological information from the target is achieved using multi-signals. Examples of multi-signal FIB/SEM tomography from a dental implant will be provided where both material contrast from the bone/ceramic coating/Ti substrate phases and porosity in the ceramic coating will be characterized.

Results from a Prototype Proton-CT Head Scanner

NASA Astrophysics Data System (ADS)

Johnson, R. P.; Bashkirov, V. A.; Coutrakon, G.; Giacometti, V.; Karbasi, P.; Karonis, N. T.; Ordoñez, C. E.; Pankuch, M.; Sadrozinski, H. F.-W.; Schubert, K. E.; Schulte, R. W.

We are exploring low-dose proton radiography and computed tomography (pCT) as techniques to improve the accuracy of proton treatment planning and to provide artifact-free images for verification and adaptive therapy at the time of treatment. Here we report on comprehensive beam test results with our prototype pCT head scanner. The detector system and data acquisition attain a sustained rate of more than a million protons individually measured per second, allowing a full CT scan to be completed in six minutes or less of beam time. In order to assess the performance of the scanner for proton radiography as well as computed tomography, we have performed numerous scans of phantoms at the Northwestern Medicine Chicago Proton Center including a custom phantom designed to assess the spatial resolution, a phantom to assess the measurement of relative stopping power, and a dosimetry phantom. Some images, performance, and dosimetry results from those phantom scans are presented together with a description of the instrument, the data acquisition system, and the calibration methods.

Digital 3D Microstructure Analysis of Concrete using X-Ray Micro Computed Tomography SkyScan 1173: A Preliminary Study

NASA Astrophysics Data System (ADS)

Latief, F. D. E.; Mohammad, I. H.; Rarasati, A. D.

2017-11-01

Digital imaging of a concrete sample using high resolution tomographic imaging by means of X-Ray Micro Computed Tomography (μ-CT) has been conducted to assess the characteristic of the sample’s structure. A standard procedure of image acquisition, reconstruction, image processing of the method using a particular scanning device i.e., the Bruker SkyScan 1173 High Energy Micro-CT are elaborated. A qualitative and a quantitative analysis were briefly performed on the sample to deliver some basic ideas of the capability of the system and the bundled software package. Calculation of total VOI volume, object volume, percent of object volume, total VOI surface, object surface, object surface/volume ratio, object surface density, structure thickness, structure separation, total porosity were conducted and analysed. This paper should serve as a brief description of how the device can produce the preferred image quality as well as the ability of the bundled software packages to help in performing qualitative and quantitative analysis.

How to Study Thermal Applications of Open-Cell Metal Foam: Experiments and Computational Fluid Dynamics

PubMed Central

De Schampheleire, Sven; De Jaeger, Peter; De Kerpel, Kathleen; Ameel, Bernd; Huisseune, Henk; De Paepe, Michel

2016-01-01

This paper reviews the available methods to study thermal applications with open-cell metal foam. Both experimental and numerical work are discussed. For experimental research, the focus of this review is on the repeatability of the results. This is a major concern, as most studies only report the dependence of thermal properties on porosity and a number of pores per linear inch (PPI-value). A different approach, which is studied in this paper, is to characterize the foam using micro tomography scans with small voxel sizes. The results of these scans are compared to correlations from the open literature. Large differences are observed. For the numerical work, the focus is on studies using computational fluid dynamics. A novel way of determining the closure terms is proposed in this work. This is done through a numerical foam model based on micro tomography scan data. With this foam model, the closure terms are determined numerically. PMID:28787894

Multi-Mounted X-Ray Computed Tomography

PubMed Central

Fu, Jian; Liu, Zhenzhong; Wang, Jingzheng

2016-01-01

Most existing X-ray computed tomography (CT) techniques work in single-mounted mode and need to scan the inspected objects one by one. It is time-consuming and not acceptable for the inspection in a large scale. In this paper, we report a multi-mounted CT method and its first engineering implementation. It consists of a multi-mounted scanning geometry and the corresponding algebraic iterative reconstruction algorithm. This approach permits the CT rotation scanning of multiple objects simultaneously without the increase of penetration thickness and the signal crosstalk. Compared with the conventional single-mounted methods, it has the potential to improve the imaging efficiency and suppress the artifacts from the beam hardening and the scatter. This work comprises a numerical study of the method and its experimental verification using a dataset measured with a developed multi-mounted X-ray CT prototype system. We believe that this technique is of particular interest for pushing the engineering applications of X-ray CT. PMID:27073911

Noninvasive imaging of oral mucosae with optical coherence tomography

NASA Astrophysics Data System (ADS)

Lee, Cheng-Yu; Chen, Wei-Chuan; Tsai, Meng-Tsan

2017-04-01

In this study, a swept-source optical coherence tomography (OCT) system is developed for in vivo visualization of structural and vascular morphology oral mucosa. For simplification of optical probe fabrication, probe weight, and system setup, the body of the scanning probe is fabricated by a 3D printer to fix the optical components and the mechanical scanning device, and a partially reflective slide is attached at the output end of probe to achieve a common-path configuration. Aside from providing the ability of 3D structural imaging with the developed system, 3D vascular images of oral mucosa can be simultaneously obtained. Then, different locations of oral mucosa are scanned with common-path OCT. The results show that epithelium and lamina propria layers as well as fungiform papilla can be identified and microvascular images can be acquired. With the proposed probe, the system cost and volume can be greatly reduced. Experimental results indicate that such common-path OCT system could be further implemented for oral cancer diagnosis.

Performance of e-ASPECTS software in comparison to that of stroke physicians on assessing CT scans of acute ischemic stroke patients.

PubMed

Herweh, Christian; Ringleb, Peter A; Rauch, Geraldine; Gerry, Steven; Behrens, Lars; Möhlenbruch, Markus; Gottorf, Rebecca; Richter, Daniel; Schieber, Simon; Nagel, Simon

2016-06-01

The Alberta Stroke Program Early CT score (ASPECTS) is an established 10-point quantitative topographic computed tomography scan score to assess early ischemic changes. We compared the performance of the e-ASPECTS software with those of stroke physicians at different professional levels. The baseline computed tomography scans of acute stroke patients, in whom computed tomography and diffusion-weighted imaging scans were obtained less than two hours apart, were retrospectively scored by e-ASPECTS as well as by three stroke experts and three neurology trainees blinded to any clinical information. The ground truth was defined as the ASPECTS on diffusion-weighted imaging scored by another two non-blinded independent experts on consensus basis. Sensitivity and specificity in an ASPECTS region-based and an ASPECTS score-based analysis as well as receiver-operating characteristic curves, Bland-Altman plots with mean score error, and Matthews correlation coefficients were calculated. Comparisons were made between the human scorers and e-ASPECTS with diffusion-weighted imaging being the ground truth. Two methods for clustered data were used to estimate sensitivity and specificity in the region-based analysis. In total, 34 patients were included and 680 (34 × 20) ASPECTS regions were scored. Mean time from onset to computed tomography was 172 ± 135 min and mean time difference between computed tomographyand magnetic resonance imaging was 41 ± 31 min. The region-based sensitivity (46.46% [CI: 30.8;62.1]) of e-ASPECTS was better than three trainees and one expert (p ≤ 0.01) and not statistically different from another two experts. Specificity (94.15% [CI: 91.7;96.6]) was lower than one expert and one trainee (p < 0.01) and not statistically different to the other four physicians. e-ASPECTS had the best Matthews correlation coefficient of 0.44 (experts: 0.38 ± 0.08 and trainees: 0.19 ± 0.05) and the lowest mean score error of 0.56 (experts: 1.44 ± 1.79 and trainees: 1.97 ± 2.12). e-ASPECTS showed a similar performance to that of stroke experts in the assessment of brain computed tomographys of acute ischemic stroke patients with the Alberta Stroke Program Early CT score method. © 2016 World Stroke Organization.

Direct Test for Neuroinflammation with [11C]DAP-713-PET Scanning

DTIC Science & Technology

2015-10-01

individuals suffering from the Gulf War Illness (GWI). We are using quantitative positron emission tomography (PET) using [11C]DPA-713 (DPA). DPA...suffering from the Gulf War Illness (GWI). We are using quantitative positron emission tomography (PET) using [11C]DPA-713 (DPA). DPA binds to the... Resistant Prostate Cancer Time commitments: 0.12 calendar months Supporting Agency: CDMRP Grants Contact: TBD PI: Denmeade Co-Investigator

Cardiac metastases of Ewing sarcoma detected by 18F-FDG PET/CT.

PubMed

Coccia, Paola; Ruggiero, Antonio; Rufini, Vittoria; Maurizi, Palma; Attinà, Giorgio; Marano, Riccardo; Natale, Luigi; Leccisotti, Lucia; Calcagni, Maria L; Riccardi, Riccardo

2012-04-01

Positron emission tomography (PET) is widely used in the diagnostic evaluation and staging of different malignant tumors. The role of PET/computed tomographic scan in detecting distant metastases in the workup of Ewing sarcoma in children or young adults is less well defined. We report a case of a boy affected by a metastatic Ewing sarcoma with cardiac asymptomatic metastasis detected by F-FDG PET/computed tomography.

An algorithm for improving the quality of structural images of turbid media in endoscopic optical coherence tomography

NASA Astrophysics Data System (ADS)

Potlov, A. Yu.; Frolov, S. V.; Proskurin, S. G.

2018-04-01

High-quality OCT structural images reconstruction algorithm for endoscopic optical coherence tomography of biological tissue is described. The key features of the presented algorithm are: (1) raster scanning and averaging of adjacent Ascans and pixels; (2) speckle level minimization. The described algorithm can be used in the gastroenterology, urology, gynecology, otorhinolaryngology for mucous membranes and skin diagnostics in vivo and in situ.

Comparison of Multidetector Computed Tomography and Flat-Panel Computed Tomography Regarding Visualization of Cortical Fractures, Cortical Defects, and Orthopedic Screws: A Phantom Study.

PubMed

Neubauer, Jakob; Benndorf, Matthias; Lang, Hannah; Lampert, Florian; Kemna, Lars; Konstantinidis, Lukas; Neubauer, Claudia; Reising, Kilian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Goerke, Sebastian M

2015-08-01

To compare the visualization of cortical fractures, cortical defects, and orthopedic screws in a dedicated extremity flat-panel computed tomography (FPCT) scanner and a multidetector computed tomography (MDCT) scanner.We used feet of European roe deer as phantoms for cortical fractures, cortical defects, and implanted orthopedic screws. FPCT and MDCT scans were performed with equivalent dose settings. Six observers rated the scans according to number of fragments, size of defects, size of defects opposite orthopedic screws, and the length of different screws. The image quality regarding depiction of the cortical bone was assessed. The gold standard (real number of fragments) was evaluated by autopsy.The correlation of reader assessment of fragments, cortical defects, and screws with the gold standard was similar for FPCT and MDCT. Three readers rated the subjective image quality of the MDCT to be higher, whereas the others showed no preferences.Although the image quality was rated higher in the MDCT than in the FPCT by 3 out of 6 observers, both modalities proved to be comparable regarding the visualization of cortical fractures, cortical defects, and orthopedic screws and of use to musculoskeletal radiology regarding fracture detection and postsurgical evaluation in our experimental setting.

Functional imaging in differentiating bronchial masses: an initial experience with a combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan.

PubMed

Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh

2009-10-01

To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.

Synthetic Incoherence via Scanned Gaussian Beams

PubMed Central

Levine, Zachary H.

2006-01-01

Tomography, in most formulations, requires an incoherent signal. For a conventional transmission electron microscope, the coherence of the beam often results in diffraction effects that limit the ability to perform a 3D reconstruction from a tilt series with conventional tomographic reconstruction algorithms. In this paper, an analytic solution is given to a scanned Gaussian beam, which reduces the beam coherence to be effectively incoherent for medium-size (of order 100 voxels thick) tomographic applications. The scanned Gaussian beam leads to more incoherence than hollow-cone illumination. PMID:27274945

Design and testing of prototype handheld scanning probes for optical coherence tomography

PubMed Central

Demian, Dorin; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Cernat, Ramona; Topala, Florin Ionel; Hutiu, Gheorghe; Bradu, Adrian; Podoleanu, Adrian Gh

2014-01-01

Three simple and low-cost configurations of handheld scanning probes for optical coherence tomography have been developed. Their design and testing for dentistry applications are presented. The first two configurations were built exclusively from available off-the-shelf optomechanical components, which, to the best of our knowledge, are the first designs of this type. The third configuration includes these components in an optimized and ergonomic probe. All the designs are presented in detail to allow for their duplication in any laboratory with a minimum effort, for applications that range from educational to high-end clinical investigations. Requirements that have to be fulfilled to achieve configurations which are reliable, ergonomic—for clinical environments, and easy to build are presented. While a range of applications is possible for the prototypes developed, in this study the handheld probes are tested ex vivo with a spectral domain optical coherence tomography system built in-house, for dental constructs. A previous testing with a swept source optical coherence tomography system has also been performed both in vivo and ex vivo for ear, nose, and throat—in a medical environment. The applications use the capability of optical coherence tomography to achieve real-time, high-resolution, non-contact, and non-destructive interferometric investigations with micrometer resolutions and millimeter penetration depth inside the sample. In this study, testing the quality of the material of one of the most used types of dental prosthesis, metalo-ceramic is thus demonstrated. PMID:25107512

Design and testing of prototype handheld scanning probes for optical coherence tomography.

PubMed

Demian, Dorin; Duma, Virgil-Florin; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Cernat, Ramona; Topala, Florin Ionel; Hutiu, Gheorghe; Bradu, Adrian; Podoleanu, Adrian Gh

2014-08-01

Three simple and low-cost configurations of handheld scanning probes for optical coherence tomography have been developed. Their design and testing for dentistry applications are presented. The first two configurations were built exclusively from available off-the-shelf optomechanical components, which, to the best of our knowledge, are the first designs of this type. The third configuration includes these components in an optimized and ergonomic probe. All the designs are presented in detail to allow for their duplication in any laboratory with a minimum effort, for applications that range from educational to high-end clinical investigations. Requirements that have to be fulfilled to achieve configurations which are reliable, ergonomic-for clinical environments, and easy to build are presented. While a range of applications is possible for the prototypes developed, in this study the handheld probes are tested ex vivo with a spectral domain optical coherence tomography system built in-house, for dental constructs. A previous testing with a swept source optical coherence tomography system has also been performed both in vivo and ex vivo for ear, nose, and throat-in a medical environment. The applications use the capability of optical coherence tomography to achieve real-time, high-resolution, non-contact, and non-destructive interferometric investigations with micrometer resolutions and millimeter penetration depth inside the sample. In this study, testing the quality of the material of one of the most used types of dental prosthesis, metalo-ceramic is thus demonstrated. © IMechE 2014.

In Vivo Detection of Laminar and Peripapillary Scleral Hypercompliance in Early Monkey Experimental Glaucoma

PubMed Central

Ivers, Kevin M.; Yang, Hongli; Gardiner, Stuart K.; Qin, Lirong; Reyes, Luke; Fortune, Brad; Burgoyne, Claude F.

2016-01-01

Purpose To compare optical coherence tomography (OCT) detected, optic nerve head (ONH) compliance within control and experimental glaucoma (EG) eyes of 15 monkeys at EG onset. Methods Intraocular pressure (IOP) was chronically elevated in one eye of each animal using a laser. Experimental glaucoma onset was identified using confocal scanning laser tomography (CSLT). Optical coherence tomography ONH imaging (40 radial B-scans) was performed at 10 mm Hg before and after laser. At EG onset, OCT scans were obtained at IOP 10 and 30 mm Hg. Optical coherence tomography landmarks within the IOP 10/30 images were delineated to quantify IOP 10/30 differences (compliance) for anterior lamina cribrosa surface depth (ALCSD) relative to Bruch's membrane opening (BMO) (ALCSD-BMO), ALCSD relative to peripheral BM (ALCSD-BM), and BMO depth relative to peripheral BM (BMOD-BM). A linear mixed effects model assessed for acute IOP elevation effects, control versus EG eye effects, and their interaction Results Effects of IOP elevation were greater in EG versus control eyes for ALCSD-BMO (−46 ± 45 vs. −8 ± 13 μm, P = 0.0042) and ALCSD-BM (−92 ± 64 vs. −42 ± 22 μm, P = 0.0075). Experimental glaucoma eye-specific ALCSD-BMO and ALCSD-BM compliance exceeded the range of control eye compliance in 9 and 8 of the 15 EG eyes, respectively. Post-laser peak IOP (R2 = 0.798, P < 0.0001) and post-laser mean IOP (R2 = 0.634, P < 0.0004) most strongly correlated to EG versus control eye differences in ALCSD-BMO compliance. Conclusions Laminar (ALCSD-BMO) and peripapillary scleral (ALCSD-BM) hypercompliance are present in most monkey eyes at the onset of EG. PMID:27409498

The effect of in situ/in vitro three-dimensional quantitative computed tomography image voxel size on the finite element model of human vertebral cancellous bone.

PubMed

Lu, Yongtao; Engelke, Klaus; Glueer, Claus-C; Morlock, Michael M; Huber, Gerd

2014-11-01

Quantitative computed tomography-based finite element modeling technique is a promising clinical tool for the prediction of bone strength. However, quantitative computed tomography-based finite element models were created from image datasets with different image voxel sizes. The aim of this study was to investigate whether there is an influence of image voxel size on the finite element models. In all 12 thoracolumbar vertebrae were scanned prior to autopsy (in situ) using two different quantitative computed tomography scan protocols, which resulted in image datasets with two different voxel sizes (0.29 × 0.29 × 1.3 mm(3) vs 0.18 × 0.18 × 0.6 mm(3)). Eight of them were scanned after autopsy (in vitro) and the datasets were reconstructed with two voxel sizes (0.32 × 0.32 × 0.6 mm(3) vs. 0.18 × 0.18 × 0.3 mm(3)). Finite element models with cuboid volume of interest extracted from the vertebral cancellous part were created and inhomogeneous bilinear bone properties were defined. Axial compression was simulated. No effect of voxel size was detected on the apparent bone mineral density for both the in situ and in vitro cases. However, the apparent modulus and yield strength showed significant differences in the two voxel size group pairs (in situ and in vitro). In conclusion, the image voxel size may have to be considered when the finite element voxel modeling technique is used in clinical applications. © IMechE 2014.

Interior tomography in microscopic CT with image reconstruction constrained by full field of view scan at low spatial resolution

NASA Astrophysics Data System (ADS)

Luo, Shouhua; Shen, Tao; Sun, Yi; Li, Jing; Li, Guang; Tang, Xiangyang

2018-04-01

In high resolution (microscopic) CT applications, the scan field of view should cover the entire specimen or sample to allow complete data acquisition and image reconstruction. However, truncation may occur in projection data and results in artifacts in reconstructed images. In this study, we propose a low resolution image constrained reconstruction algorithm (LRICR) for interior tomography in microscopic CT at high resolution. In general, the multi-resolution acquisition based methods can be employed to solve the data truncation problem if the project data acquired at low resolution are utilized to fill up the truncated projection data acquired at high resolution. However, most existing methods place quite strict restrictions on the data acquisition geometry, which greatly limits their utility in practice. In the proposed LRICR algorithm, full and partial data acquisition (scan) at low and high resolutions, respectively, are carried out. Using the image reconstructed from sparse projection data acquired at low resolution as the prior, a microscopic image at high resolution is reconstructed from the truncated projection data acquired at high resolution. Two synthesized digital phantoms, a raw bamboo culm and a specimen of mouse femur, were utilized to evaluate and verify performance of the proposed LRICR algorithm. Compared with the conventional TV minimization based algorithm and the multi-resolution scout-reconstruction algorithm, the proposed LRICR algorithm shows significant improvement in reduction of the artifacts caused by data truncation, providing a practical solution for high quality and reliable interior tomography in microscopic CT applications. The proposed LRICR algorithm outperforms the multi-resolution scout-reconstruction method and the TV minimization based reconstruction for interior tomography in microscopic CT.

Effect of field-of-view size on gray values derived from cone-beam computed tomography compared with the Hounsfield unit values from multidetector computed tomography scans

PubMed Central

Shokri, Abbas; Bidgoli, Mohsen; Akbarzadeh, Mahdi; Ghazikhanlu-Sani, Karim; Fallahi-Sichani, Hamed

2018-01-01

Purpose This study aimed to evaluate the effect of field-of-view (FOV) size on the gray values derived from conebeam computed tomography (CBCT) compared with the Hounsfield unit values from multidetector computed tomography (MDCT) scans as the gold standard. Materials and Methods A radiographic phantom was designed with 4 acrylic cylinders. One cylinder was filled with distilled water, and the other 3 were filled with 3 types of bone substitute: namely, Nanobone, Cenobone, and Cerabone. The phantom was scanned with 2 CBCT systems using 2 different FOV sizes, and 1 MDCT system was used as the gold standard. The mean gray values (MGVs) of each cylinder were calculated in each imaging protocol. Results In both CBCT systems, significant differences were noted in the MGVs of all materials between the 2 FOV sizes (P<.05) except for Cerabone in the Cranex3D system. Significant differences were found in the MGVs of each material compared with the others in both FOV sizes for each CBCT system. No significant difference was seen between the Cranex3D CBCT system and the MDCT system in the MGVs of bone substitutes on images obtained with a small FOV. Conclusion The size of the FOV significantly changed the MGVs of all bone substitutes, except for Cerabone in the Cranex3D system. Both CBCT systems had the ability to distinguish the 3 types of bone substitutes based on a comparison of their MGVs. The Cranex3D CBCT system used with a small FOV had a significant correlation with MDCT results. PMID:29581947

Fan-beam scanning laser optical computed tomography for large volume dosimetry

NASA Astrophysics Data System (ADS)

Dekker, K. H.; Battista, J. J.; Jordan, K. J.

2017-05-01

A prototype scanning-laser fan beam optical CT scanner is reported which is capable of high resolution, large volume dosimetry with reasonable scan time. An acylindrical, asymmetric aquarium design is presented which serves to 1) generate parallel-beam scan geometry, 2) focus light towards a small acceptance angle detector, and 3) avoid interference fringe-related artifacts. Preliminary experiments with uniform solution phantoms (11 and 15 cm diameter) and finger phantoms (13.5 mm diameter FEP tubing) demonstrate that the design allows accurate optical CT imaging, with optical CT measurements agreeing within 3% of independent Beer-Lambert law calculations.

System requirements for a computerised patient record information system at a busy primary health care clinic.

PubMed

Blignaut, P J; McDonald, T; Tolmie, C J

2001-05-01

A prototyping approach was used to determine the essential system requirements of a computerised patient record information system for a typical township primary health care clinic. A pilot clinic was identified and the existing manual system and business processes in this clinic was studied intensively before the first prototype was implemented. Interviews with users, incidental observations and analysis of actual data entered were used as primary techniques to refine the prototype system iteratively until a system with an acceptable data set and adequate functionalities were in place. Several non-functional and user-related requirements were also discovered during the prototyping period.

The effect of maternal methadone use on the fetal heart pattern: a computerised CTG analysis.

PubMed

Navaneethakrishnan, R; Tutty, S; Sinha, C; Lindow, S W

2006-08-01

Using a computerised analysis, the cardiotocograph (CTG) from women who use methadone (n= 25) when compared with women who do not use methadone (n= 25) showed a significant reduction in the fetal heart baseline rate, with a significant reduction in number of accelerations and episodes of high variation. The short-term variation, number of decelerations and episodes of low variation were not different between the two groups. The time taken to meet the standardised criteria was not different, and it is possible that a computer-assisted CTG analysis could be more accurate than a naked eye interpretation.

[Survey on computerized immunization registries in Italy].

PubMed

Alfonsi, V; D'Ancona, F; Ciofi degli Atti, M L

2008-01-01

Computerized immunization registries are essential for conducting and monitoring vaccination programs. In fact, they enable to improve vaccine offering to target population, generating needed-immunization lists and assessing levels of vaccination coverage. In 2007, a national survey on immunization registries was conducted in Italy. In February 2007, all the 21 Regional Health Authorities (RHAs) completed and returned an ad hoc questionnaire. In June 2007, RHAs were further contacted by telephone in order to verify and update the information provided in questionnaires. In 9 Italian Regions (42.8%), vaccination registries are computerized in all Local Health Units (LHUs). In five of these Regions, all LHUs use the same software, while in the remaining four Regions, different softwares are in use. In six additional Regions (28.6%), only some LHUs use computerized immunization registries (range 61.5%-95%). In the remaining 6 Regions (28.6%), which are all in Southern Italy, there are no computerised immunization registries at all. In total, computerised immunization registries cover 126/180 Italian LHUs (70%); in 76/126 (60%) of these LUHs, immunization registries are linked with population registries. This survey shows the need to improve the implementation of computerised immunization registries in Italy, especially in Southern Regions.

Computerised analysis of facial emotion expression in eating disorders.

PubMed

Leppanen, Jenni; Dapelo, Marcela Marin; Davies, Helen; Lang, Katie; Treasure, Janet; Tchanturia, Kate

2017-01-01

Problems with social-emotional processing are known to be an important contributor to the development and maintenance of eating disorders (EDs). Diminished facial communication of emotion has been frequently reported in individuals with anorexia nervosa (AN). Less is known about facial expressivity in bulimia nervosa (BN) and in people who have recovered from AN (RecAN). This study aimed to pilot the use of computerised facial expression analysis software to investigate emotion expression across the ED spectrum and recovery in a large sample of participants. 297 participants with AN, BN, RecAN, and healthy controls were recruited. Participants watched film clips designed to elicit happy or sad emotions, and facial expressions were then analysed using FaceReader. The finding mirrored those from previous work showing that healthy control and RecAN participants expressed significantly more positive emotions during the positive clip compared to the AN group. There were no differences in emotion expression during the sad film clip. These findings support the use of computerised methods to analyse emotion expression in EDs. The findings also demonstrate that reduced positive emotion expression is likely to be associated with the acute stage of AN illness, with individuals with BN showing an intermediate profile.

Exploring the impact of instructional approaches on the learning and transfer of medication dosage calculation competency.

PubMed

Glaister, Karen

2005-09-01

The ability of nurses to perform accurate drug dosage calculations has repercussions for patients' well-being. How best to assist nurses develop competency in this area is paramount. This paper presents findings of a study conducted with undergraduate nurses to determine the effect of three instructional approaches on the learning of this skill. The quasi-experimental study exposed participants to one of three instructional approaches: integrative learning, computerised learning and a combination of integrative and computerised learning. Quantitative and qualitative approaches were used to explore differences in the instructional approaches and gain further understanding of the learning process. There was no statistical difference between the three instructional approaches on knowledge acquisition and transfer measures, other than measures for procedural knowledge, which was significant (F(2,47) = 3.33 at p < .044). A least-significant difference post hoc test (alpha = 0. 10) indicated computerised learning was significantly more effective in developing procedural knowledge. The provision of instructional strategies, which facilitate development of conditional knowledge and automaticity, is necessary for competency development in dosage calculations. Furthermore, the curriculum must incorporate authentic tasks and permit time to support competency attainment.

Take Away Body Parts! An Investigation into the Use of 3D-Printed Anatomical Models in Undergraduate Anatomy Education

ERIC Educational Resources Information Center

Smith, Claire F.; Tollemache, Nicholas; Covill, Derek; Johnston, Malcolm

2018-01-01

Understanding the three-dimensional (3D) nature of the human form is imperative for effective medical practice and the emergence of 3D printing creates numerous opportunities to enhance aspects of medical and healthcare training. A recently deceased, un-embalmed donor was scanned through high-resolution computed tomography. The scan data underwent…

Automated labeling of log features in CT imagery of multiple hardwood species

Treesearch

Daniel L. Schmoldt; Jing He; A. Lynn Abbott

2000-01-01

Before noninvasive scanning, e.g., computed tomography (CT), becomes feasible in industrial saw-mill operations, we need a procedure that can automatically interpret scan information in order to provide the saw operator with information necessary to make proper sawing decisions. To this end, we have worked to develop an approach for automatic analysis of CT images of...

Multi-mounted X-ray cone-beam computed tomography

NASA Astrophysics Data System (ADS)

Fu, Jian; Wang, Jingzheng; Guo, Wei; Peng, Peng

2018-04-01

As a powerful nondestructive inspection technique, X-ray computed tomography (X-CT) has been widely applied to clinical diagnosis, industrial production and cutting-edge research. Imaging efficiency is currently one of the major obstacles for the applications of X-CT. In this paper, a multi-mounted three dimensional cone-beam X-CT (MM-CBCT) method is reported. It consists of a novel multi-mounted cone-beam scanning geometry and the corresponding three dimensional statistical iterative reconstruction algorithm. The scanning geometry is the most iconic design and significantly different from the current CBCT systems. Permitting the cone-beam scanning of multiple objects simultaneously, the proposed approach has the potential to achieve an imaging efficiency orders of magnitude greater than the conventional methods. Although multiple objects can be also bundled together and scanned simultaneously by the conventional CBCT methods, it will lead to the increased penetration thickness and signal crosstalk. In contrast, MM-CBCT avoids substantially these problems. This work comprises a numerical study of the method and its experimental verification using a dataset measured with a developed MM-CBCT prototype system. This technique will provide a possible solution for the CT inspection in a large scale.

Whole-body computed tomography in trauma patients: optimization of the patient scanning position significantly shortens examination time while maintaining diagnostic image quality.

PubMed

Hickethier, Tilman; Mammadov, Kamal; Baeßler, Bettina; Lichtenstein, Thorsten; Hinkelbein, Jochen; Smith, Lucy; Plum, Patrick Sven; Chon, Seung-Hun; Maintz, David; Chang, De-Hua

2018-01-01

The study was conducted to compare examination time and artifact vulnerability of whole-body computed tomographies (wbCTs) for trauma patients using conventional or optimized patient positioning. Examination time was measured in 100 patients scanned with conventional protocol (Group A: arms positioned alongside the body for head and neck imaging and over the head for trunk imaging) and 100 patients scanned with optimized protocol (Group B: arms flexed on a chest pillow without repositioning). Additionally, influence of two different scanning protocols on image quality in the most relevant body regions was assessed by two blinded readers. Total wbCT duration was about 35% or 3:46 min shorter in B than in A. Artifacts in aorta (27 vs 6%), liver (40 vs 8%) and spleen (27 vs 5%) occurred significantly more often in B than in A. No incident of non-diagnostic image quality was reported, and no significant differences for lungs and spine were found. An optimized wbCT positioning protocol for trauma patients allows a significant reduction of examination time while still maintaining diagnostic image quality.

Evaluation of artifacts generated by zirconium implants in cone-beam computed tomography images.

PubMed

Vasconcelos, Taruska Ventorini; Bechara, Boulos B; McMahan, Clyde Alex; Freitas, Deborah Queiroz; Noujeim, Marcel

2017-02-01

To evaluate zirconium implant artifact production in cone beam computed tomography images obtained with different protocols. One zirconium implant was inserted in an edentulous mandible. Twenty scans were acquired with a ProMax 3D unit (Planmeca Oy, Helsinki, Finland), with acquisition settings ranging from 70 to 90 peak kilovoltage (kVp) and voxel sizes of 0.32 and 0.16 mm. A metal artifact reduction (MAR) tool was activated in half of the scans. An axial slice through the middle region of the implant was selected for each dataset. Gray values (mean ± standard deviation) were measured in two regions of interest, one close to and the other distant from the implant (control area). The contrast-to-noise ratio was also calculated. Standard deviation decreased with greater kVp and when the MAR tool was used. The contrast-to-noise ratio was significantly higher when the MAR tool was turned off, except for low resolution with kVp values above 80. Selection of the MAR tool and greater kVp resulted in an overall reduction of artifacts in images acquired with low resolution. Although zirconium implants do produce image artifacts in cone-bean computed tomography scans, the setting that best controlled artifact generation by zirconium implants was 90 kVp at low resolution and with the MAR tool turned on. Copyright © 2016 Elsevier Inc. All rights reserved.

Identifying and classifying hyperostosis frontalis interna via computerized tomography.

PubMed

May, Hila; Peled, Nathan; Dar, Gali; Hay, Ori; Abbas, Janan; Masharawi, Youssef; Hershkovitz, Israel

2010-12-01

The aim of this study was to recognize the radiological characteristics of hyperostosis frontalis interna (HFI) and to establish a valid and reliable method for its identification and classification. A reliability test was carried out on 27 individuals who had undergone a head computerized tomography (CT) scan. Intra-observer reliability was obtained by examining the images three times, by the same researcher, with a 2-week interval between each sample ranking. The inter-observer test was performed by three independent researchers. A validity test was carried out using two methods for identifying and classifying HFI: 46 cadaver skullcaps were ranked twice via computerized tomography scans and then by direct observation. Reliability and validity were calculated using Kappa test (SPSS 15.0). Reliability tests of ranking HFI via CT scans demonstrated good results (K > 0.7). As for validity, a very good consensus was obtained between the CT and direct observation, when moderate and advanced types of HFI were present (K = 0.82). The suggested classification method for HFI, using CT, demonstrated a sensitivity of 84%, specificity of 90.5%, and positive predictive value of 91.3%. In conclusion, volume rendering is a reliable and valid tool for identifying HFI. The suggested three-scale classification is most suitable for radiological diagnosis of the phenomena. Considering the increasing awareness of HFI as an early indicator of a developing malady, this study may assist radiologists in identifying and classifying the phenomena.

Computerized tomography versus magnetic resonance imaging: a comparative study in hypothalamic-pituitary and parasellar pathology.

PubMed

Webb, S M; Ruscalleda, J; Schwarzstein, D; Calaf-Alsina, J; Rovira, A; Matos, G; Puig-Domingo, M; de Leiva, A

1992-05-01

We wished to analyse the relative value of computerized tomography and magnetic resonance in patients referred for evaluation of pituitary and parasellar lesions. We performed a separate evaluation by two independent neuroradiologists of computerized tomography and magnetic resonance images ordered numerically and anonymously, with no clinical data available. We studied 40 patients submitted for hypothalamic-pituitary study; 31 were carried out preoperatively, of which histological confirmation later became available in 14. The remaining nine patients were evaluated postoperatively. Over 40 parameters relating to the bony margins, cavernous sinuses, carotid arteries, optic chiasm, suprasellar cisterns, pituitary, pituitary stalk and extension of the lesion were evaluated. These reports were compared with the initial ones offered when the scans were ordered, and with the final diagnosis. Concordance between initial computerized tomography and magnetic resonance was observed in 27 cases (67.5%); among the discordant cases computerized tomography showed the lesion in two, magnetic resonance in 10, while in the remaining case reported to harbour a microadenoma on computerized tomography the differential diagnosis between a true TSH-secreting microadenoma and pituitary resistance to thyroid hormones is still unclear. Both neuroradiologists coincided in their reports in 32 patients (80%); when the initial report was compared with those of the neuroradiologists, concordance was observed with at least one of them in 34 instances (85%). Discordant results were observed principally in microadenomas secreting ACTH or PRL and in delayed puberty. In the eight patients with Cushing's disease (histologically confirmed in six) magnetic resonance was positive in five and computerized tomography in two; the abnormal image correctly identified the side of the lesion at surgery. In patients referred for evaluation of Cushing's syndrome or hyperprolactinaemia (due to microadenomas) or after surgery, magnetic resonance is clearly preferable to computerized tomography. In macroadenomas both scans are equally diagnostic but magnetic resonance offers more information on pituitary morphology and neighbouring structures. Nevertheless, there are cases in which the results of computerized tomography and magnetic resonance will complement each other, since different parameters are analysed with each examination and discordant results are encountered.

Single-Photon Emission Computed Tomography/Computed Tomography Imaging in a Rabbit Model of Emphysema Reveals Ongoing Apoptosis In Vivo

PubMed Central

Goldklang, Monica P.; Tekabe, Yared; Zelonina, Tina; Trischler, Jordis; Xiao, Rui; Stearns, Kyle; Romanov, Alexander; Muzio, Valeria; Shiomi, Takayuki; Johnson, Lynne L.

2016-01-01

Evaluation of lung disease is limited by the inability to visualize ongoing pathological processes. Molecular imaging that targets cellular processes related to disease pathogenesis has the potential to assess disease activity over time to allow intervention before lung destruction. Because apoptosis is a critical component of lung damage in emphysema, a functional imaging approach was taken to determine if targeting apoptosis in a smoke exposure model would allow the quantification of early lung damage in vivo. Rabbits were exposed to cigarette smoke for 4 or 16 weeks and underwent single-photon emission computed tomography/computed tomography scanning using technetium-99m–rhAnnexin V-128. Imaging results were correlated with ex vivo tissue analysis to validate the presence of lung destruction and apoptosis. Lung computed tomography scans of long-term smoke–exposed rabbits exhibit anatomical similarities to human emphysema, with increased lung volumes compared with controls. Morphometry on lung tissue confirmed increased mean linear intercept and destructive index at 16 weeks of smoke exposure and compliance measurements documented physiological changes of emphysema. Tissue and lavage analysis displayed the hallmarks of smoke exposure, including increased tissue cellularity and protease activity. Technetium-99m–rhAnnexin V-128 single-photon emission computed tomography signal was increased after smoke exposure at 4 and 16 weeks, with confirmation of increased apoptosis through terminal deoxynucleotidyl transferase dUTP nick end labeling staining and increased tissue neutral sphingomyelinase activity in the tissue. These studies not only describe a novel emphysema model for use with future therapeutic applications, but, most importantly, also characterize a promising imaging modality that identifies ongoing destructive cellular processes within the lung. PMID:27483341

Epilepsy Surgery

MedlinePlus

... monitor the brain's activity and detect abnormalities. Single-photon emission computerized tomography (SPECT). The scan image varies ... off anti-seizure drugs after a year or two. By Mayo Clinic Staff . Mayo Clinic Footer Legal ...

Endoscopic optical coherence tomography with a focus-adjustable probe.

PubMed

Liao, Wenchao; Chen, Tianyuan; Wang, Chengming; Zhang, Wenxin; Peng, Zhangkai; Zhang, Xiao; Ai, Shengnan; Fu, Deyong; Zhou, Tieying; Xue, Ping

2017-10-15

We present a focus-adjustable endoscopic probe for optical coherence tomography (OCT), which is able to acquire images with different focal planes and overcome depth-of-focus limitations by image fusing. The use of a two-way shape-memory-alloy spring enables the probe to adjust working distance over 1.5 mm, providing a large scanning range with high resolution and no sensitivity loss. Equipped with a homemade hollow-core ultrasonic motor, the probe is capable of performing an unobstructed 360 deg field-of-view distal scanning. Both the axial resolution and the best lateral resolution are ∼4  μm, with a sensitivity of 100.3 dB. Spectral-domain OCT imaging of phantom and biological tissues with the probe is also demonstrated.

[Observing effect of treatment of the second branchial fistula with endoscopic resection].

PubMed

Jiang, Jiping; Wang, Shuyun; Tong, Kang

2014-03-01

To explore synergic effect of treatment of the second branchial fistula with endoscopic resection. All patients of the second branchial fistula were scanned in neck with CT (computed tomography), we injected ioversol-320 from the entrance of the second branchial fistula in front of sternocleidomastiod into the second branchial fistula, then scanned the neck with CT (computed tomography), and rebuilding the picture of the second branchial fistula, to prepare for the operation. 9 patients of the second branchial fistula were operated under general anesthesia with endoscopic resection. All of 9 patients were cured. no one recurred after follow-up of 6 months. It is minimally invasive and complete to resect the second branchial with endoscopic resection, the operation is simply and easy to promote.

Colonic obstruction secondary to incarcerated Spigelian hernia in a severely obese patient.

PubMed

Salemis, Nikolaos S; Kontoravdis, Nikolaos; Gourgiotis, Stavros; Panagiotopoulos, Nikolaos; Gakis, Christos; Dimitrakopoulos, Georgios

2010-01-01

Spigelian hernia is a rare hernia of the ventral abdominal wall accounting for 1-2% of all hernias. Incarceration of a Spigelian hernia has been reported in 17-24% of the cases. We herein describe an extremely rare case of a colonic obstruction secondary to an incarcerated Spigelian hernia in a severely obese patient. Physical examination was inconclusive and diagnosis was established by computed tomography scans. The patient underwent an open intraperitoneal mesh repair. A high level of suspicion and awareness is required as clinical findings of a Spigelian hernia are often nonspecific especially in obese patients. Computed tomography scan provides detailed information for the surgical planning. Open mesh repair is safe in the emergent surgical intervention of a complicated Spigelian hernia in severely obese patients.

Colonic obstruction secondary to incarcerated Spigelian hernia in a severely obese patient

PubMed Central

Salemis, Nikolaos S.; Kontoravdis, Nikolaos; Gourgiotis, Stavros; Panagiotopoulos, Nikolaos; Gakis, Christos; Dimitrakopoulos, Georgios

2010-01-01

Spigelian hernia is a rare hernia of the ventral abdominal wall accounting for 1–2% of all hernias. Incarceration of a Spigelian hernia has been reported in 17–24% of the cases. We herein describe an extremely rare case of a colonic obstruction secondary to an incarcerated Spigelian hernia in a severely obese patient. Physical examination was inconclusive and diagnosis was established by computed tomography scans. The patient underwent an open intraperitoneal mesh repair. A high level of suspicion and awareness is required as clinical findings of a Spigelian hernia are often nonspecific especially in obese patients. Computed tomography scan provides detailed information for the surgical planning. Open mesh repair is safe in the emergent surgical intervention of a complicated Spigelian hernia in severely obese patients. PMID:22096670

Simulation of Medical Imaging Systems: Emission and Transmission Tomography

NASA Astrophysics Data System (ADS)

Harrison, Robert L.

Simulation is an important tool in medical imaging research. In patient scans the true underlying anatomy and physiology is unknown. We have no way of knowing in a given scan how various factors are confounding the data: statistical noise; biological variability; patient motion; scattered radiation, dead time, and other data contaminants. Simulation allows us to isolate a single factor of interest, for instance when researchers perform multiple simulations of the same imaging situation to determine the effect of statistical noise or biological variability. Simulations are also increasingly used as a design optimization tool for tomographic scanners. This article gives an overview of the mechanics of emission and transmission tomography simulation, reviews some of the publicly available simulation tools, and discusses trade-offs between the accuracy and efficiency of simulations.

Fourier domain mode locking at 1050 nm for ultra-high-speed optical coherence tomography of the human retina at 236,000 axial scans per second.

PubMed

Huber, R; Adler, D C; Srinivasan, V J; Fujimoto, J G

2007-07-15

A Fourier domain mode-locked (FDML) laser at 1050 nm for ultra-high-speed optical coherence tomography (OCT) imaging of the human retina is demonstrated. Achievable performance, physical limitations, design rules, and scaling principles for FDML operation and component choice in this wavelength range are discussed. The fiber-based FDML laser operates at a sweep rate of 236 kHz over a 63 nm tuning range, with 7 mW average output power. Ultra-high-speed retinal imaging is demonstrated at 236,000 axial scans per second. This represents a speed improvement of approximately10x over typical high-speed OCT systems, paving the way for densely sampled volumetric data sets and new imaging protocols.

In vivo endoscopic optical coherence tomography by use of a rotational microelectromechanical system probe

NASA Astrophysics Data System (ADS)

Tran, Peter H.; Mukai, David S.; Brenner, Matthew; Chen, Zhongping

2004-06-01

A novel endoscopic optical coherence tomography probe was designed and constructed with a 1.9-mm microelectromechanical system (MEMS) motor. The new MEMS endoscopic probe design eliminates the need to couple the rotational energy from the proximal to the distal end of the probe. Furthermore, the endoscopic probe's sheath and fiber have the advantages of having a much smaller diameter and being more flexible than traditional endoscopes since no reinforcement is needed to couple the rotational torque. At the distal end, a prism mounted on a micromotor deflects the light rays to create a transverse circular-scanning pathway. Because our MEMS scanner does not require the coupling of a rotational single-mode fiber, a high scanning speed is possible while eliminating unstable optical signals caused by nonuniform coupling.

Capillary red blood cell velocimetry by phase-resolved optical coherence tomography.

PubMed

Tang, Jianbo; Erdener, Sefik Evren; Fu, Buyin; Boas, David A

2017-10-01

We present a phase-resolved optical coherence tomography (OCT) method to extend Doppler OCT for the accurate measurement of the red blood cell (RBC) velocity in cerebral capillaries. OCT data were acquired with an M-mode scanning strategy (repeated A-scans) to account for the single-file passage of RBCs in a capillary, which were then high-pass filtered to remove the stationary component of the signal to ensure an accurate measurement of phase shift of flowing RBCs. The angular frequency of the signal from flowing RBCs was then quantified from the dynamic component of the signal and used to calculate the axial speed of flowing RBCs in capillaries. We validated our measurement by RBC passage velocimetry using the signal magnitude of the same OCT time series data.

Normal cross-sectional anatomy of the bovine digit: comparison of computed tomography and limb anatomy.

PubMed

Raji, A R; Sardari, K; Mohammadi, H R

2008-06-01

The purpose of this study was to define the structures of the digits and hoof in Holstein dairy cattle by using computed tomography scan (CT scan). Transverse, sagittal and dorsoplantar CT images of two isolated cattle cadaver digits were obtained using a Siemens ARTX2 Somatom. The CT images were compared to corresponding frozen cross-sections. Relevant anatomical structures were identified and labelled at each level. The CT images provided anatomical detail of the digits and hoof in Holstein dairy cattle. Transversal images provided excellent depiction of anatomical structures when compared to corresponding frozen cross-sections. The information presented in this paper would serve as an initial reference to the evaluation of CT images of the digits and hoof in Holstein dairy cattle.

Nonrigid registration of 3D longitudinal optical coherence tomography volumes with choroidal neovascularization

NASA Astrophysics Data System (ADS)

Wei, Qiangding; Shi, Fei; Zhu, Weifang; Xiang, Dehui; Chen, Haoyu; Chen, Xinjian

2017-02-01

In this paper, we propose a 3D registration method for retinal optical coherence tomography (OCT) volumes. The proposed method consists of five main steps: First, a projection image of the 3D OCT scan is created. Second, the vessel enhancement filter is applied on the projection image to detect vessel shadow. Third, landmark points are extracted based on both vessel positions and layer information. Fourth, the coherent point drift method is used to align retinal OCT volumes. Finally, a nonrigid B-spline-based registration method is applied to find the optimal transform to match the data. We applied this registration method on 15 3D OCT scans of patients with Choroidal Neovascularization (CNV). The Dice coefficients (DSC) between layers are greatly improved after applying the nonrigid registration.

Laboratory x-ray micro-computed tomography: a user guideline for biological samples

PubMed Central

2017-01-01

Abstract Laboratory x-ray micro–computed tomography (micro-CT) is a fast-growing method in scientific research applications that allows for non-destructive imaging of morphological structures. This paper provides an easily operated “how to” guide for new potential users and describes the various steps required for successful planning of research projects that involve micro-CT. Background information on micro-CT is provided, followed by relevant setup, scanning, reconstructing, and visualization methods and considerations. Throughout the guide, a Jackson's chameleon specimen, which was scanned at different settings, is used as an interactive example. The ultimate aim of this paper is make new users familiar with the concepts and applications of micro-CT in an attempt to promote its use in future scientific studies. PMID:28419369

Fundamentals of cone beam computed tomography for a prosthodontist

PubMed Central

John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R. B.

2015-01-01

Cone beam computed tomography (CBCT, also referred to as C-arm computed tomography [CT], cone beam volume CT, or flat panel CT) is a medical imaging technique of X-ray CT where the X-rays are divergent, forming a cone.[1] CBCT systems have been designed for imaging hard tissues of the maxillofacial region. CBCT is capable of providing sub-millimeter resolution in images of high diagnostic quality, with short scanning times (10–70 s) and radiation dosages reportedly up to 15–100 times lower than those of conventional CT scans. Increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. The aim of this article is to sensitize the Prosthodontist to CBCT technology, provide an overview of currently available maxillofacial CBCT systems and review the specific application of various CBCT display modes to clinical Prosthodontic practice. A MEDLINE search for relevant articles in this specific area of interest was conducted. The selected articles were critically reviewed and the data acquired were systematically compiled. PMID:26929479

Quantitative features in the computed tomography of healthy lungs.

PubMed Central

Fromson, B H; Denison, D M

1988-01-01

This study set out to determine whether quantitative features of lung computed tomography scans could be identified that would lead to a tightly defined normal range for use in assessing patients. Fourteen normal subjects with apparently healthy lungs were studied. A technique was developed for rapid and automatic extraction of lung field data from the computed tomography scans. The Hounsfield unit histograms were constructed and, when normalised for predicted lung volumes, shown to be consistent in shape for all the subjects. A three dimensional presentation of the data in the form of a "net plot" was devised, and from this a logarithmic relationship between the area of each lung slice and its mean density was derived (r = 0.9, n = 545, p less than 0.0001). The residual density, calculated as the difference between measured density and density predicted from the relationship with area, was shown to be normally distributed with a mean of 0 and a standard deviation of 25 Hounsfield units (chi 2 test: p less than 0.05). A presentation combining this residual density with the net plot is described. PMID:3353883

Surgical accuracy with the mini-subvastus total knee arthroplasty a computer tomography scan analysis of postoperative implant alignment.

PubMed

Schroer, William C; Diesfeld, Paul J; Reedy, Mary E; Lemarr, Angela R

2008-06-01

A total of 50 total knee arthroplasty (TKA) patients, 25 traditional and 25 minimally invasive surgical (MIS), underwent computed tomography scans to determine if a loss of accuracy in implant alignment occurred when a surgeon switched from a traditional medial parapatellar arthrotomy to a mini-subvastus surgical technique. Surgical accuracy was determined by comparing the computed tomography measured implant alignment with the surgical alignment goals. There was no loss in accuracy in the implantation of the tibial component with the mini-subvastus technique. The mean variance for the tibial coronal alignment was 1.03 degrees for the traditional TKA and 1.00 degrees for the MIS TKA (P = .183). Similarly, there was no difference in the mean variance for the posterior tibial slope (P = .054). Femoral coronal alignment was less accurate with the MIS procedure, mean variance of 1.04 degrees and 1.71 degrees for the traditional and MIS TKA, respectively (P = .045). Instrumentation and surgical technique concerns that led to this loss in accuracy were determined.

Real time en face Fourier-domain optical coherence tomography with direct hardware frequency demodulation

PubMed Central

Biedermann, Benjamin R.; Wieser, Wolfgang; Eigenwillig, Christoph M.; Palte, Gesa; Adler, Desmond C.; Srinivasan, Vivek J.; Fujimoto, James G.; Huber, Robert

2009-01-01

We demonstrate en face swept source optical coherence tomography (ss-OCT) without requiring a Fourier transformation step. The electronic optical coherence tomography (OCT) interference signal from a k-space linear Fourier domain mode-locked laser is mixed with an adjustable local oscillator, yielding the analytic reflectance signal from one image depth for each frequency sweep of the laser. Furthermore, a method for arbitrarily shaping the spectral intensity profile of the laser is presented, without requiring the step of numerical apodization. In combination, these two techniques enable sampling of the in-phase and quadrature signal with a slow analog-to-digital converter and allow for real-time display of en face projections even for highest axial scan rates. Image data generated with this technique is compared to en face images extracted from a three-dimensional OCT data set. This technique can allow for real-time visualization of arbitrarily oriented en face planes for the purpose of alignment, registration, or operator-guided survey scans while simultaneously maintaining the full capability of high-speed volumetric ss-OCT functionality. PMID:18978919