Author(s): Arpita C1, Nava Kishore K2, Ananda Reddy C3, Dushyanth M4
BACKGROUND AND PURPOSE Magnetic Resonance (MR) urography with its optimal contrast resolution and lack of ionizing radiation provides a comprehensive examination of the entire urinary tract noninvasively. MR urography is clinically useful in the evaluation of suspected urinary tract obstruction, haematuria, congenital anomalies, and surgically altered anatomy. It is particularly useful in cases of where there is contraindication of ionizing radiation and in paediatric and pregnant patients. The common MR urographic techniques are: Static-fluid MR urography and excretory MR urography. Static-fluid MR urography uses of heavily T2-weighted sequences to image the urinary tract as a static collection of fluid, can be repeated sequentially (Cine MR urography) to better demonstrate the ureters in their entirety and to confirm the presence of fixed stenoses. Excretory MR urography is performed during the excretory phase of enhancement after the intravenous administration of gadolinium-based contrast material; thus, the patient must have sufficient renal function to allow the excretion. Static-fluid and excretory MR urography can be combined with conventional MR imaging for comprehensive evaluation of the urinary tract. The limitations are limited availability, high cost, relatively long examination time, low spatial resolution compared to IVU (Intravenous Urogram) and CT Urography; sensitivity to motion (breathing and ureteral peristalsis) inherent contraindications like patients with pacemakers, claustrophobia, and relative insensitivity for calcification and ureteric calculi. In this article, an attempt has been made to demonstrate the potential of static-fluid MRU to demonstrate a spectrum of urologic pathology involving the kidneys, ureters, and bladder while discussing the limitations.
METHODS Thirty patients with urinary tract abnormalities were evaluated with MR urography performed between May 2014 to April 2016 using routine MR sequences and additional heavily T2 weighted sequence on a 1.5 Tesla MRI machine. Images were post processed using MIP algorithm. Both, the reconstructed and source images were evaluated.
RESULTS Static-fluid MR urography correctly depicted the presence of urinary tract dilatation and level of obstruction. It also succeeded in depicting the cause of obstruction.
CONCLUSION MR urography allows comprehensive imaging of the urinary tract abnormalities non-invasively without using ionizing radiation.
To study the efficacy of static MR urography in comparison with conventional urography. To study the levels and causes of obstruction of urinary tract by MR urography and compare them with other investigation procedures.