Effect of contrast leakage on the detection of abnormal brain tumor vasculature in high-grade glioma.

Abnormal brain tumor vasculature has recently been highlighted by a dynamic susceptibility contrast (DSC) MRI processing technique. The technique uses independent component analysis (ICA) to separate arterial and venous perfusion. The overlap of the two, i.e. arterio-venous overlap or AVOL, preferentially occurs in brain tumors and predicts response to anti-angiogenic therapy. The effects of contrast agent leakage on the AVOL biomarker have yet to be established. DSC was acquired during two separate contrast boluses in ten patients undergoing clinical imaging for brain tumor diagnosis. Three components were modeled with ICA, which included the arterial and venous components. The percentage of each component as well as a third component were determined within contrast enhancing tumor and compared. AVOL within enhancing tumor was also compared between doses. The percentage of enhancing tumor classified as not arterial or venous and instead into a third component with contrast agent leakage apparent in the time-series was significantly greater for the first contrast dose compared to the second. The amount of AVOL detected within enhancing tumor was also significantly greater with the second dose compared to the first. Contrast leakage results in large signal variance classified as a separate component by the ICA algorithm. The use of a second dose mitigates the effect and allows measurement of AVOL within enhancement.

Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex.

The imaging evaluation and interpretation of the triangular fibrocartilage complex (TFCC) is both challenging and rewarding for the radiologist and surgeon alike. The TFCC comprises a complicated group of fibrocartilaginous and ligamentous structures at the ulnar aspect of the wrist that plays an important role in wrist biomechanics. It is the main stabilizer of the distal radioulnar and ulnocarpal joints and functions to distribute compressive forces at the ulnocarpal joint during axial loading. Derangement of the TFCC is the most common source of ulnar-sided wrist pain. Imaging plays an important role in the diagnosis and management of these lesions. The TFCC can anatomically be divided into proximal and distal parts to emphasize the role that the proximal TFCC has in stabilizing the distal radioulnar joint. Tears can be divided into traumatic and degenerative categories using the Palmer classification. Further subclassification based on the location for traumatic tears and the degree of derangement in degenerative tears guides clinical management. The vascular anatomy is important in determining management options for various lesions. A detailed understanding of the normal anatomy of the TFCC, imaging limitations and pitfalls, the Palmer classification system, and current treatment options is critical to the accurate and clinically useful interpretation of radiologic examinations of the TFCC.

PI-RADS Version 2 Is an Excellent Screening Tool for Clinically Significant Prostate Cancer as Designated by the Validated International Society of Urological Pathology Criteria: A Retrospective Analysis.

OBJECTIVES: To assess the utility of multiparametric MRI in detecting clinically significant prostate cancer (csPCa) by comparing PI-RADSv2 scores with International Society of Urological Pathology (ISUP) pathologic grading criteria. METHODS: Data from 137 patients were retrospectively analyzed. PI-RADSv2 scores were compared with pathologic grade using ISUP criteria. Pathologic grades were divided into clinically significant (groups 3-5) and clinically insignificant lesions (groups 1-2). Chi-squared analysis was performed for to assess correlation. RESULTS: Sensitivity and specificity of PI-RADSv2 score 3-5 lesions for detecting csPCa was 100% and 18.5%, respectively. Negative predictive value (NPV) is 100% for these lesions. When considering only PI-RADSv2 score 4-5 lesions, sensitivity decreases to 90% and specificity increases to 67.5%, with a NPV of 98.5%. When only PI-RADSv2 score 5 lesions are considered, sensitivity decreases to 50% and specificity increases to 90%, with a NPV of 95%. CONCLUSIONS: Multiparametric MRI has excellent sensitivity for detecting csPCa. Specificity is poor for PI-RADSv2 score 3 lesions but improves significantly for PI-RADSv2 score 4 and 5 lesions. Overall, mpMRI is an excellent screening tool for csPCa, as designated by the recently validated ISUP criteria. ADVANCES IN KNOWLEDGE: Multiple limitations of the longstanding Gleason pathologic scoring system have led to the development of new ISUP pathologic criteria, which is more focused on the clinical significance of lesions. There are currently insufficient studies evaluating and validating the ISUP criteria with PIRADS v2 evaluation of the prostate.