Skull fractures in pediatric patients on computerized tomogram: comparison between routing bone window images and 3D volume-rendered images.

Skull fracture is a common finding following head trauma. It has a prognostic significance and its presence points to severe trauma. Additionally, there is a greater possibility of detecting associated small underlying extra-axial hematomas and subtle injuries to the brain parenchyma. In pediatric patients, the presence of multiple open sutures often makes fracture evaluation challenging. In our experience, 3D volume (3DV)-rendered CT images complement routine axial bone window (RBW) images in detection and characterization of fractures. This is a multi-reader, multi-case, paired retrospective study to compare the sensitivity and specificity of RBW and 3DV images in detection of calvarial fractures in pediatric patients. A total of 60 cases (22 with fractures and 38 without) were analyzed. Two experienced neuroradiologists and a radiology trainee were the readers of the study. For all readers, the sensitivity was not statistically different between the RBW and the 3DV interpretations. For each reader, there was a statistically significant difference in the interpretation times between the RBW and the 3DV viewing formats. A greater number of sutural diastasis was identified on 3DV. We propose that 3DV images should be part of routine head trauma imaging, especially in the pediatric age group. It requires minimal post-processing time and no additional radiation. Furthermore, 3DV images help in reducing the interpretation time and also enhance the ability of the radiologist to characterize the calvarial fractures.

Correlation of apparent diffusion coefficient with Ki-67 proliferation index in grading meningioma.

OBJECTIVE: A noninvasive method to predict aggressiveness of high-grade meningiomas would be desirable because it would help anticipate tumor recurrence and improve tumor management and the treatment outcomes. The Ki-67 protein is a marker of tumor proliferation, and apparent diffusion coefficient (ADC) is related to tumor cellularity. Therefore, we sought to determine whether there is a statistically significant correlation between ADC and Ki-67 values in meningiomas and whether ADC values can differentiate various meningioma subtypes. MATERIALS AND METHODS: MRI examinations and histopathology of 68 surgically treated meningiomas were retrospectively reviewed. Mean ADC values were derived from diffusion imaging. Correlation coefficients were calculated for mean ADC and Ki-67 proliferation index values using linear regression. An independent unpaired Student t test was used to compare the ADC and Ki-67 proliferation index values from low-grade and more aggressive meningiomas. RESULTS: A statistically significant inverse correlation was found between ADC and Ki-67 proliferation index for low-grade and aggressive meningiomas (r(2) = -0.33, p = 0.0039). ADC values (± SD) of low-grade meningiomas (0.84 ± 0.14 × 10(-3) mm(2)/s) and aggressive (atypical or anaplastic) meningiomas (0.75 ± 0.03 × 10(-3) mm(2)/s) were significantly different (p = 0.0495). Using an ADC cutoff value of 0.70 × 10(-3) mm(2)/s, the sensitivity for diagnosing aggressive meningiomas was 29%, specificity was 94%, positive predictive value was 67%, and negative predictive value was 75%. CONCLUSION: ADC values correlate inversely with Ki-67 proliferation index and help differentiate low-grade from aggressive meningiomas.

Dynamic contrast-enhanced MRI findings of acute pancreatitis in ectopic pancreatic tissue: case report and review of the literature.

CONTEXT: Acute pancreatitis in ectopic pancreatic tissue is an uncommon cause of acute abdominal pain and can be difficult to diagnose on imaging. Our aim is to raise awareness and aid in the diagnosis of this entity by highlighting helpful dynamic contrast-enhanced MRI imaging findings. CASE REPORT: We report a 51-year-old man with acute onset epigastric pain presented to ER. With the presence of elevated serum lipase, the clinical diagnosis of acute pancreatitis was made. Contrast enhanced CT demonstrated normal pancreas and a focal mass at the duodenojejunal flexure, mimicked a neoplasm. Subsequent dynamic contrast enhanced MR images demonstrated enhancement pattern of the lesion similar to the native pancreatic tissue enhancement, a finding raised the possibility of acute pancreatitis in ectopic pancreatic tissue, but tumor was not excluded. Finally, patient undergone surgical bowel resection including the suspected mass that was proved as an ectopic pancreatic tissue on microscopic examination. CONCLUSION: We concluded that findings on dynamic contrast enhanced MR imaging can be characteristic and diagnostic of acute pancreatitis in ectopic pancreatic tissue in the appropriate clinical setting.

Quantitative radiomics and qualitative LI-RADS imaging descriptors for non-invasive assessment of ß-catenin mutation status in hepatocellular carcinoma.

PURPOSE: Gain-of-function mutations in CTNNB1, gene encoding for ß-catenin, are observed in 25-30% of hepatocellular carcinomas (HCCs). Recent studies have shown ß-catenin activation to have distinct roles in HCC susceptibility to mTOR inhibitors and resistance to immunotherapy. Our goal was to develop and test a computational imaging-based model to non-invasively assess ß-catenin activation in HCC, since liver biopsies are often not done due to risk of complications. METHODS: This IRB-approved retrospective study included 134 subjects with pathologically proven HCC and available ß-catenin activation status, who also had either CT or MR imaging of the liver performed within 1 year of histological assessment. For qualitative descriptors, experienced radiologists assessed the presence of imaging features listed in LI-RADS v2018. For quantitative analysis, a single biopsy proven tumor underwent a 3D segmentation and radiomics features were extracted. We developed prediction models to assess the ß-catenin activation in HCC using both qualitative and quantitative descriptors. RESULTS: There were 41 cases (31%) with ß-catenin mutation and 93 cases (69%) without. The model's AUC was 0.70 (95% CI 0.60, 0.79) using radiomics features and 0.64 (0.52, 0.74; p = 0.468) using qualitative descriptors. However, when combined, the AUC increased to 0.88 (0.80, 0.92; p = 0.009). Among the LI-RADS descriptors, the presence of a nodule-in-nodule showed a significant association with ß-catenin mutations (p = 0.015). Additionally, 88 radiomics features exhibited a significant association (p < 0.05) with ß-catenin mutations. CONCLUSION: Combination of LI-RADS descriptors and CT/MRI-derived radiomics determine ß-catenin activation status in HCC with high confidence, making precision medicine a possibility.

Improved image quality and detection of small cerebral infarctions with diffusion-tensor trace imaging.

OBJECTIVE: The purpose of this study was to test a hypothesis that routinely performed diffusion-tensor trace imaging is of sufficient image quality and sensitivity for infarct detection to safely and routinely replace standard diffusion-weighted imaging (DWI) in the clinical setting. MATERIALS AND METHODS: Both routine DWI and 15-direction diffusion-tensor imaging (DTI) with parallel acquisition technique were obtained on all brain MRI studies from a single 1.5-T MRI scanner at a tertiary care referral center over a 1-year period, permitting direct comparison of the two different diffusion studies on the same patients (2537 studies, 365 infarct-positive studies). A subset of images was assessed for image quality and quantitatively for ability to detect brain infarctions. The total set of positive studies was reviewed qualitatively for ability to detect small cerebral infarctions. RESULTS: Fifteen-direction isotropic DWI (DTI trace images) with parallel acquisition technique resulted in consistently higher image quality with less distortion and higher image detail than routine DWI. Small infarcts were better seen, and in 12 cases, infarcts could only be seen on 15-direction isotropic diffusion-weighted images. The additional scanning time required for 15-direction isotropic DWI did not result in significantly increased motion-related reduction in image quality compared with standard DWI. CONCLUSION: Diffusion-tensor trace images obtained with parallel acquisition technique are of improved image quality and improved sensitivity for detection of small cerebral infarctions relative to standard DWI. If such DTI data are acquired, routine DWI can be omitted.

Application of compressed sensing to 3D magnetic resonance cholangiopancreatography for the evaluation of pancreatic cystic lesions.

The aim of this study was to assess changes in acquisition time, image quality and evaluation of pancreatic cysts when applying CS to a 3D MRCP sequence. Thirty subjects (17F; 13M) undergoing MRCP for evaluation of pancreatic cyst(s) were prospectively recruited and underwent 3D MRCP and CS 3D MRCP (CS factor = 2) on a 3T scanner. The acquisition time was recorded. Two experienced radiologists independently recorded quality of the images, presence of artifacts, visualization of the main pancreatic duct, bile ducts and index pancreatic cyst using a five-point scale. Presence of mural nodules and septations in the cyst, size of the cyst and caliber of the main pancreatic duct were also recorded. A paired sample t-test was used to compare the acquisition time of 3D MRCP and CS 3D MRCP. Image quality metrics and visualization of cyst features were compared with Wilcoxon signed-rank test and McNemar test. The mean acquisition time of CS-3D-MRCP (150 ±â€¯63 s) was significantly lower than that of 3D-MRCP (317 ±â€¯104 s; P < 0.001). The median score of overall quality (reader 1, 3.7 ±â€¯1.0 vs. 3.4 ±â€¯1.1, P = 0.11; reader 2, 3.8 ±â€¯1.0 vs. 3.7 ±â€¯1.1, P = 0.36), artifacts and visualization of the bile ducts were not significantly different between 3D-MRCP and CS-3D-MRCP. There was no significant difference in the visualization score of the index pancreatic cyst (reader 1, 4.2 ±â€¯0.9 vs. 4.1 ±â€¯0.9, P = 0.42; reader 2, 4.2 ±â€¯0.4 vs. 4.0 ±â€¯0.7, P = 0.27) and no difference in the assessment of cyst features. Applying CS to 3D-MRCP yields a two-fold reduction in acquisition time with comparable image quality and visualization of key pancreatic cyst features.

External carotid artery embolus with internal carotid artery occlusion with acute ischemic stroke: predictor of cardioembolic etiology.

Arteriograms performed in the Interventional Management of Stroke studies were analyzed for external carotid artery embolus. Two cases were identified and diagnosed as thromboembolic due to a cardiac origin. This is an uncommon but useful finding on angiography which is helpful for further management. It is hypothesized that finding embolus within the external carotid artery on angiography in stroke patients with internal carotid artery occlusion allows confident ascription to a proximal, usually cardiac, source.