RELATIVE BLOOD-VOLUME MEASUREMENTS BY MAGNETIC-RESONANCE-IMAGING FACILITATE DETECTION OF TESTICULAR TORSION

RATIONALE AND OBJECTIVES. The authors determine the utility of relativ e blood volume measurements (rBV) using a blood pool marker for magnet ic resonance imaging (MRI) in detection of early testicular torsion. M ETHODS. Testicular torsion was induced in rats by counterclockwise 720 degrees rotation and fixation of the testis in the scrotum, MPEG-PL-D TPA-Gd enhanced MRI (30 mu mol Gd/kg bolus injection) was performed 1 hour after torsion at 1.5 T using fat-suppressed three-dimensional fas t spoiled gradient-recalled sequence for relative blood volume measure ment and three-dimensional time-of-flight sequence for MR angiography (MRA). RESULTS. The rBV of the torqued testes was significantly lower (13.3% +/- 13.5%) than that of testes with sham operation (97.7% +/- 5 .3%; P < 0.05), Rats with testicular torsion showed larger regions of ischemia than did animals with sham operation (63.4% +/- 13.0% versus 4.0% +/- 2.8% of all pixels in testis; P < 0.01), The MRA of testicula r torsion showed engorgement of the distal testicular vein as a sign o f venous compression or total disappearance of the testicular vein, in dicating arterial insufficiency. CONCLUSIONS. The authors conclude tha t MPEG-PL-DTPA-Gd can be used to obtain functional (rBV), morphologic (tunica enhancement), and angiographic (venous engorgement, arterial c ompromise) findings that should improve the diagnosis of testicular to rsion in the acute setting.