The role of static magnetic resonance urography in the evaluation of obstructive uropathy.

OBJECTIVE: To assess the diagnostic accuracy of static magnetic resonance urography (MRU) in hydronephrosis and to compare parameters of hydronephrosis in MRU with intravenous urography (IVU). MATERIALS AND METHODS: Sixty-nine patients were included in this study of which 55 patients with a total of 63 hydronephrotic units underwent both IVU and MRU. MRU was performed on a 1.5 T scanner using heavily T2-weighted sequences. The level, grade, and cause of obstruction on each modality were interpreted by 2 radiologists. These were compared with the final diagnosis based on other appropriate modalities including imaging, intraoperative and histopathologic diagnosis. RESULTS: The sensitivity and specificity MRU in detecting hydronephrosis were 95% and 100%, respectively. In determining the level of obstruction, the strength of agreement between IVU and MRU using kappa statistics was κ = 0.66, which corresponds to a good level of agreement. The Spearman correlation coefficient for the grade of hydronephrosis on MRU and IVU was 0.92 (95% confidence interval 0.86-0.95), with a P value of < .0001. The correct diagnosis was made in 89.2% of the cases by IVU and in 93.8% of the cases by MRU. CONCLUSION: Along with a high sensitivity and specificity in detecting the presence, level, and grade of hydronephrosis, MRU without contrast also shows a good agreement with IVU. Static MRU can reliably replace IVU when the latter is contraindicated or technically difficult.

Biodistribution properties of cleistanthin A and cleistanthin B using magnetic resonance imaging in a normal and tumoric animal model.

AIM: To determine the biodistribution properties of cleistanthin A and cleistanthin B in rodents using magnetic resonance imaging (MRI). MATERIALS AND METHODS: Cleistanthins A and B, constituents of Cleistanthus collinus Roxb., were labelled with gadolinium (Gd(3+)) directly and injected into normal and tumoric nude mice. The tissue signal intensity was measured using MRI to perform a noninvasive kinetic assay. Wistar rats were used for determination of the grayscale intensity to observe the distribution patterns of of cleistanthins A and B. RESULTS: Cleistanthin A is kinetically more attractive to the gastrointestinal tract than is cleistanthin B, which gets accumulated in muscular tissues of mice in greater concentrations compared with cleistanthin A. Cleistanthin B but not cleistanthin A showed tumoric affinity and exhibited a tumor kinetic attraction in tumoric mice. In rats, cleistanthin A showed greater grayscale intensities in the brain, liver, and skeletal muscles in immediate post contrast MRI images, whereas the gadolinium tagged cleistanthin B showed higher grayscale intensities in the cardiac muscle and skeletal muscles in delayed post contrast MRI images. CONCLUSIONS: Cleistanthin A is more pharmacokinetically attractive to the gastrointestinal tract than cleistanthin B.