Assessment of urinary tract calculi with 64-MDCT: The axial versus coronal plane.

OBJECTIVE: The objective of our study was to compare the detection rate, conspicuity, and size measurements of urinary tract calculi on coronal reformations versus the axial plane using 64-MDCT. MATERIALS AND METHODS: For this retrospective study, 80 consecutive CT examinations performed for clinical diagnosis of renal colic or for the assessment of known nephrolithiasis were evaluated. All studies were stripped of patient identifiers, and the axial and coronal plane images of each study were randomized and presented to two abdominal radiologists. For each study, the radiologists recorded the number and location of stones, diagnostic confidence and stone conspicuity (subjectively on a 2-point scale), and stone size. The standard of reference was data from a consensus reading with the study coordinator examining the same parameters on images in both planes of each patient. Detection rates were compared between planes using logistic regression with generalized estimating equations to account for multiple stones per patient. RESULTS: On consensus reading, 272 stones were identified. For all renal stones, the coronal plane detected more stones as compared with the axial plane (p < 0.001). For stones smaller than 5 mm, a higher proportion received the maximal conspicuity score on the coronal plane than on the axial plane (p < 0.001). Both reviewers better estimated stone size on the coronal plane than the axial plane (p = 0.02); their axial plane measurements underestimated stone size by 13.4% (mean). CONCLUSION: The detection of stones and estimation of maximal stone diameter were improved using coronal reformations. The conspicuity of stones and diagnostic confidence in identifying stones smaller than 5 mm in diameter were also improved on the coronal plane.

Perianal sepsis: surgical perspective and practical MRI reporting for radiologists.

This article describes the development of a structured MRI reporting template and diagrammatic worksheet for perianal sepsis through collaboration between radiologists and colorectal surgeons at our institution, and the rationale behind each component of the worksheet. Benefits of this reporting worksheet include optimizing communication of key imaging findings that have a real impact on patient management, less time spent on reporting the study, and easier comparison between studies. We illustrate the utility of the report template with case studies. We summarize the current surgical approaches to perianal sepsis to help radiologists focus on reporting the findings relevant to surgical planning.

HCC screening: assessment of an abbreviated non-contrast MRI protocol.

BACKGROUND: Hepatocellular carcinoma (HCC) guidelines recommend ultrasound screening in high-risk patients. However, in some patients, ultrasound image quality is suboptimal due to factors such as hepatic steatosis, cirrhosis, and confounding lesions. Our aim was to investigate an abbreviated non-contrast magnetic resonance imaging (aNC-MRI) protocol as a potential alternative screening method. METHODS: A retrospective study was performed using consecutive liver MRI studies performed over 3 years, with set exclusion criteria. The unenhanced T2-weighted, T1-weighted Dixon, and diffusion-weighted sequences were extracted from MRI studies with a known diagnosis. Each anonymised aNC-MRI study was read by three radiologists who stratified each study into either return to 6 monthly screening or investigate with a full contrast-enhanced MRI study. RESULTS: A total of 188 patients were assessed; 28 of them had 42 malignant lesions, classified as Liver Imaging Reporting and Data System 4, 5, or M. On a per-patient basis, aNC-MRI had a negative predictive value (NPV) of 97% (95% confidence interval [CI] 95-98%), not significantly different in patients with steatosis (99%, 95% CI 93-100%) and no steatosis (97%, 95% CI 94-98%). Per-patient sensitivity and specificity were 85% (95% CI 75-91%) and 93% (95% CI 90-95%). CONCLUSION: Our aNC-MRI HCC screening protocol demonstrated high specificity (93%) and NPV (97%), with a sensitivity (85%) comparable to that of ultrasound and gadoxetic acid contrast-enhanced MRI. This screening method was robust to hepatic steatosis and may be considered an alternative in the case of suboptimal ultrasound image quality.

The importance of renal localization with MIBG scintigraphy.

Although I-123 metaiodobenzylguanidine (MIBG) imaging is a well-validated technique for identification and evaluation of a pheochromocytoma, accurate interpretation can be confounded by tracer retention within the renal pelvis. The authors report two cases of abnormal MIBG accumulation in which renal localization was essential. In the first case, renal localization revealed uptake inferomedial to the left kidney in what was proved to be an extra-adrenal paraganglioma. In the second case, MIBG uptake in a similar location on the right was caused by uptake in the renal pelvis, a physiologic finding. When the location of MIBG uptake in the upper abdomen is uncertain, a renal scan should be obtained to exclude the possibility of radiolabeled MIBG tracer retention within the collecting system, a potential false-positive diagnosis of pheochromocytoma.

Pituitary incidentaloma found on O-(2-18F-fluoroethyl)-l-tyrosine PET.

Although incidental pituitary findings on (18)F-FDG PET are uncommon, there are several reports published in the literature. It is believed that this is the first reporting of incidental pituitary disease found on O-(2-(18)F-fluoroethyl)-l-tyrosine ((18)F-FET) PET imaging. The case provides valuable insight into pathogenesis, diagnostic tools, and related pathology. The power of (18)F-FET in differentiating cerebral metastases and recurrence in patients who had previous surgical and radiation therapy is highlighted, and the incremental benefits over MR imaging and (18)F-FDG PET are outlined. The case represents an uncommon finding on MR imaging and (18)F-FDG PET and a rare finding on (18)F-FET PET.