Dynamic whole-body 18F-FDG PET for differentiating abnormal lesions from physiological uptake.

PURPOSE: Serial assessment of visual change in 18F-FDG uptake on whole-body 18F-FDG PET imaging was performed to differentiate pathological uptake from physiological uptake in the urinary and gastrointestinal tracts. METHODS: In 88 suspected cancer patients, serial 3-min dynamic whole-body PET imaging was performed four times, from 60 min after 18F-FDG administration. In dynamic image evaluation, high 18F-FDG uptake was evaluated by two nuclear medicine physicians and classified as "changed" or "unchanged" based on change in uptake shape over time. Detectability of pathological uptake based on these criteria was assessed and compared with conventional image evaluation. RESULTS: Dynamic whole-body PET imaging provided images of adequate quality for visual assessment. Dynamic image evaluation was "changed" in 118/154 regions of high physiological 18F-FDG uptake (77%): in 9/19 areas in the stomach (47%), in 32/39 in the small intestine (82%), in 17/33 in the colon (52%), and in 60/63 in the urinary tract (95%). In the 86 benign or malignant lesions, 84 lesions (98%) were "unchanged." A high 18F-FDG uptake area that shows no change over time using these criteria is highly likely to represent pathological uptake, with sensitivity of 97%, specificity of 76%, PPV of 70%, NPV of 98%, and accuracy of 84%. CONCLUSION: Dynamic whole-body 18F-FDG PET imaging enabled differentiation of pathological uptake from physiological uptake in the urinary and gastrointestinal tracts, based on visual change of uptake shape.

The split sign: The MRI equivalent of the bell clapper deformity.

METHODS:: The cases of eight patients who underwent MRI and surgery for acute scrotum between January 2010 and January 2017 were evaluated. We recorded whether hyperintense fluid on T2 weighted images existed between the posterior aspect of the epididymis and the scrotal wall ("split sign") and investigated if it correlated with BCD in surgical findings. RESULTS:: In one patient without hydrocele, readers were unable to evaluate the anatomy of the tunica vaginalis. Among seven patients with hydrocele, five had the split sign and all were surgically confirmed as BCD. In two patients with hydrocele but no split sign, one had normal scrotal anatomy and the other had a BCD with a necrotic testis adherent to the scrotal wall. CONCLUSION:: The split sign on MRI corresponded well to the lack of fixation of the epididymis to the scrotal wall and detected BCD with high sensitivity (5/6). ADVANCES IN KNOWLEDGE:: A hyperintense area on T2 weighted image between the posterior aspect of the epididymis and scrotal wall ("split sign") is a useful MRI finding for diagnosing BCD.

Diagnostic performance of initial enhancement analysis using ultra-fast dynamic contrast-enhanced MRI for breast lesions.

OBJECTIVES: To assess the diagnostic value and contribution to BI-RADS categorisation of initial enhancement on ultra-fast DCE-MRI for differentiating malignant and benign breast lesions. METHODS: The institutional review board approved this study, and written informed consent was obtained from each participant. Both ultra-fast DCE-MRI for initial enhancement analysis and conventional MRI were performed on 200 subjects with a total of 215 lesions (147 malignant and 68 benign). BI-RADS categorisation of enhancing lesions was performed using the conventional MRI. Two initial enhancement measures, time to enhancement (TTE) and maximum slope (MS), were derived from the ultra-fast DCE-MRI. Diagnostic performance and the additional diagnostic value of adding TTE and MS to BI-RADS were evaluated. RESULTS: Both TTE and MS showed significant differences between malignant and benign breast lesions in masses (TTE, p <.001; MS, p = .006) and non-mass enhancement (NME) (TTE, p <.001; MS, p <.001). For masses, the AUC of TTE+MS combined with BI-RADS (0.864) was better than BI-RADS alone (0.823, p = .065). For NME, the AUC of TTE+MS combined with BI-RADS (0.923) was significantly larger than BI-RADS alone (0.865, p = .036), and diagnostic specificity improved by 40.9% (p = .005), without a significant decrease in the sensitivity (p = .083). CONCLUSION: Initial enhancement analysis using ultra-fast DCE-MRI is especially useful for increasing the diagnostic performance of NME in breast MRI. KEY POINTS: • Ultra-fast dynamic MRI effectively differentiates benign from malignant breast lesions. • Ultra-fast dynamic MRI contributes to BI-RADS categorisation in non-mass enhancement. • Management of non-mass breast lesions becomes more appropriate.

Reading efficiency can be improved by minor modification of assigned duties; a pilot study on a small team of general radiologists.

PURPOSE: To assess whether alterations in the type of duty assignment system can affect the reading efficiency and stress level of diagnostic radiologists. MATERIALS AND METHODS: Fourteen board-certified diagnostic radiologists were enrolled. We investigated three different reading systems for 1 week each. System 1 is our default, in which there are no assigned duties and everyone finishes when all cases are done. In system 2, two late shift readers are assigned every day, and, after everyone else leaves at a fixed time (5:30 p.m.), they take all remaining cases until they are finished. In system 3, a dedicated single reader is assigned to finish 30 cases, and everyone else will read all remaining cases. The total time required for reading and the number of cases read were recorded. In addition, participants completed two questionnaires regarding work-related stress. RESULTS: There was a trend toward shorter finishing time in system 2 and 3 compared to system 1 (P = 0.072 and 0.012). In terms of working stress, the subjective burden was lighter when systems 2 or 3 were employed. CONCLUSION: Minor modification of the duty assignment system has the potential to improve working efficiency and may reduce the work-related stress of diagnostic radiologists.