Effect of Dynamic Workstation Use on Radiologist Detection of Pulmonary Nodules on CT.

PURPOSE: The aim of this study was to determine the effects of using a treadmill workstation during CT interpretation on radiologists' sensitivity for lung nodule detection, accuracy and adherence to accepted management recommendations, and examination interpretation time. METHODS: This HIPAA-compliant study was approved by the institutional review board. Three radiologists performed a retrospective review of 55 CT examinations of the chest originally performed for lung cancer screening. These studies were reviewed both while sitting at a conventional workstation and while walking at a treadmill workstation. A separate thoracic radiologist reviewed the examinations at a conventional workstation only to serve as a control. The number of pulmonary nodules detected, accuracy of or adherence to follow-up recommendations, and time required for examination interpretation were recorded and compared between each condition. RESULTS: There was no statistically significant difference in the total number of nodules detected while walking versus seated. Intraobserver follow-up recommendations were consistent to highly consistent between sitting and walking. There was moderate interobserver agreement between the radiologists' recommendation for seated versus walking conditions. There was a statistically significant difference in time taken to complete each examination, with interpretation during walking taking less time than during sitting. CONCLUSIONS: Use of a treadmill workstation does not significantly affect the detection of lung nodules on CT or lead to changes in management recommendations but does decrease examination interpretation time.

Effectiveness of screening for craniosynostosis with ultrasound: a retrospective review.

BACKGROUND: Minimizing the ionizing radiation dose to children is fundamental to pediatric radiology. The most widely accepted imaging examination for evaluating craniosynostosis is computed tomography (CT) of the head, an examination that involves ionizing radiation. OBJECTIVE: To determine if sonography of the cranial sutures is an adequate screening examination for the diagnosis of craniosynostosis in patients with abnormal skull shape. MATERIALS AND METHODS: A retrospective review of all cranial suture ultrasound (US) examinations performed during the course of a 3-year period (July 2012 - September 2015) was undertaken. Results were compared with clinical follow-up and/or head CT to evaluate the accuracy of this modality as a screening tool to determine the presence or absence of craniosynostosis. Fifty-two sonographic exams were adequate for inclusion. RESULTS: Forty-five of the examinations did not reveal synostosis. In each of these instances, follow-up physical exam findings and/or CT imaging confirmed that no abnormal premature suture closure was present. US findings demonstrated synostosis in seven cases. CT exam or operative reports of these cases confirmed all seven findings of premature suture closure. Statistical analysis demonstrated a sensitivity of 100% (95% confidence interval [CI]: 56.1-100.0%), a specificity of 100% (95% CI: 90.2-100.0%), and a negative predictive value of 100% (95% CI: 90.2-100.0%). CONCLUSION: Cranial US is a reliable screening tool to rule out craniosynostosis in patients with abnormal head shape.

Odontoid process inclination in normal adults and in an adult population with Chiari malformation Type I.

OBJECT: Posterior odontoid process inclination has been demonstrated as a factor associated with Chiari malformation Type I (CM-I) in the pediatric population; however, no studies to date have examined this measurement in the adult CM-I population. The purpose of this study was to evaluate craniocervical junction (CCJ) measurements in adult CM-I versus a control group. METHODS: The odontoid retroflexion, odontoid retroversion, odontoid height, posterior basion to C-2 line measured to the dural margin (pB-C2 line), posterior basion to C-2 line measured to the dorsal odontoid cortical margin (pB-C2* line), and clivus-canal angle measurements were retrospectively analyzed in adult patients with CM-I using MRI. These measurements were compared with normative values established from CT scans of the cervical spine in adults without CM-I. RESULTS: A statistically significant difference was found between 55 adults with CM-I and 150 sex-matched controls (125 used for analysis) in the mean clivus-canal angle and the mean pB-C2 line. CONCLUSIONS: These data suggest that there are sex-specific differences with respect to measurements at the CCJ between men and women, with women showing a more posteriorly inclined odontoid process. There were also differences between the CM-I and control groups: a more acute clivus-canal angle was associated with CM-I in the adult population. These CCJ findings could have an influence on presurgical planning.

3D lumbar spine intervertebral disc segmentation and compression simulation from MRI using shape-aware models.

PURPOSE: More accurate and robust image segmentations are needed for identification of spine pathologies and to assist with spine surgery planning and simulation. A framework for 3D segmentation of healthy and herniated intervertebral discs from T2-weighted magnetic resonance imaging was developed that exploits weak shape priors encoded in simplex mesh active surface models. METHODS: Weak shape priors inherent in simplex mesh deformable models have been exploited to automatically segment intervertebral discs. An ellipsoidal simplex template mesh was initialized within the disc image boundary through affine landmark-based registration and was allowed to deform according to image gradient forces. Coarse-to-fine multi-resolution approach was adopted in conjunction with decreasing shape memory forces to accurately capture the disc boundary. User intervention is allowed to turn off the shape feature and guide model deformation when the internal simplex shape memory influence hinders detection of pathology. A resulting surface mesh was utilized for disc compression simulation under gravitational and weight loads using Simulation Open Framework Architecture. For testing, 16 healthy discs were automatically segmented, and five pathological discs were segmented with minimal supervision. RESULTS: Segmentation results were validated against expert guided segmentation and demonstrate mean absolute shape distance error of <1 mm. Healthy intervertebral disc compression simulation resulted in a bulging disc under vertical pressure of 100 N/cm(2). CONCLUSION: This study presents the application of a simplex active surface model featuring weak shape priors for 3D segmentation of healthy as well as herniated discs. A framework was developed that enables the application of shape priors in the healthy part of disc anatomy, with user intervention when the priors were inapplicable. The surface-mesh-based segmentation method is part of a processing pipeline for anatomical modelling to support interactive surgery simulation.

Estimation of odontoid process posterior inclination, odontoid height, and pB-C2 line in the adult population.

OBJECT: Posterior odontoid process inclination has been associated with Chiari malformation Type I in the pediatric population. There are varying reports to support a reliable range of odontoid inclination angles in control adults. The purpose of this study is to estimate the normal measurements in adults for odontoid retroflexion, retroversion, height, and the pB-C2 line (a line drawn through the odontoid tip from the ventral dura perpendicular to a second line from drawn the basion to the inferoposterior aspect of C-2 vertebral body) to establish a normative reference in this population. METHODS: After obtaining institutional review board approval, the authors performed a retrospective analysis of non-contrast enhanced cervical spine CT scans obtained in 150 consecutive control adults. Three neuroradiologists measured odontoid retroflexion, odontoid retroversion, odontoid height, and the pB-C2 line. The cohort was divided into sex and two age groups. Comparisons of the means with unpaired 2-tailed t-test were performed. RESULTS: A total of 125 subjects met the inclusion criteria; 80 were men and 45 were women (mean age 52 years, range 18-89 years). The odontoid retroflexion angle ranged from 70° to 89° (mean 79.3° ± 4.9°), and the odontoid retroversion angle ranged from 57° to 87° (mean 71.9° ± 5.3°). The range and mean of odontoid height were 17-27 mm and 22 ± 1.8 mm, respectively. The mean pB-C2 line was 6.5 ± 2.1 mm with a range of 0-11.2 mm. The results were also compared with previously published pediatric data. CONCLUSIONS: The current study demonstrates that the odontoid process in adults is anatomically different from that in children: it is longer, more posteriorly inclined, and has a greater pB-C2 line. Therefore, utilization of these parameters with previously published cutoffs in the pediatric population is not appropriate for surgical planning in adults.

Noncontrast computed tomographic Hounsfield unit evaluation of cerebral venous thrombosis: a quantitative evaluation.

INTRODUCTION: Our objective is to determine the utility of noncontrast Hounsfield unit values, Hounsfield unit values corrected for the patient's hematocrit, and venoarterial Hounsfield unit difference measurements in the identification of intracranial venous thrombosis on noncontrast head computed tomography. METHODS: We retrospectively reviewed noncontrast head computed tomography exams performed in both normal patients and those with cerebral venous thrombosis, acquiring Hounsfield unit values in normal and thrombosed cerebral venous structures. Also, we acquired Hounsfield unit values in the internal carotid artery for comparison to thrombosed and nonthrombosed venous structures and compared the venous Hounsfield unit values to the patient's hematocrit. RESULTS: A significant difference is identified between Hounsfield unit values in thrombosed and nonthrombosed venous structures. Applying Hounsfield unit threshold values of greater than 65, a Hounsfield unit to hematocrit ratio of greater than 1.7, and venoarterial difference values greater than 15 alone and in combination, the majority of cases of venous thrombosis are identifiable on noncontrast head computed tomography. CONCLUSION: Absolute Hounsfield unit values, Hounsfield unit to hematocrit ratios, and venoarterial Hounsfield unit value differences are a useful adjunct in noncontrast head computed tomographic evaluation of cerebral venous thrombosis.

Computed tomographic angiography in evaluation of superficial temporal to middle cerebral artery bypass.

Catheter-directed digital subtraction angiography (DSA) is considered the standard for evaluation of superficial temporal to middle cerebral artery (STA-MCA) bypass patency. Few clinical investigations have been performed that evaluate the efficacy of computed tomographic angiography (CTA) in the assessment of extracranial-intracranial bypass. Using multi-detector row CTA, STA-MCA bypass patency was assessed in the initial postoperative period and several months afterward and compared with DSA. No significant difference was identified in the evaluation of graft patency between DSA and CTA. Although multiple modalities exist to evaluate STA-MCA bypass graft patency, the multidetector CTA is widely available and allows for rapid, accurate patency assessment.