Breath-hold 3D gadolinium-enhanced subtraction MRA in the detection of transplant renal artery stenosis.

ABSTRACT

AIMS: The purpose of this study was to assess the value of breath-hold 3D gadolinium-enhanced subtraction magnetic resonance angiography (GD-MRA) in the detection of transplant renal artery stenosis (TRAS). PATIENTS AND METHODS: Seven patients with suspected post-transplant renal artery stenosis were studied. GD-MRA was performed at 1.5T with a 3D fast spoiled gradient recalled echo (FSPGR) pulse sequence. Before injection of contrast medium, the 3D pulse sequence was performed to obtain a set of non-contrast images for subtraction purposes. Dynamic 3D imaging was performed simultaneously with the bolus injection of 40 ml of gadopentetate dimeglumine. Angiographic images were reconstructed using the Advantage Window workstation (version 2.0 GE Medical Systems) and subtraction was made with the pre-contrast image data. Any signal intensity cut-off or narrowing of more than 50% was regarded as significant stenosis. Ultrasound Doppler (USD) study was performed with both colour and spectral studies. Peak systolic velocity (PSV) of greater than 2.0 m/s and acceleration time (AT) greater than 120ms was regarded as positive for TRAS. These were then compared with the digital subtraction angiography (DSA) as the gold standard. RESULTS: A total of nine examinations performed in seven patients were included in the analysis. MRA correlated with the DSA findings in eight examinations, with one false negative. USG correlated with DSA in six examinations, with two false negative and one false positive case. CONCLUSION: In our opinion, GD-MRA is a promising and non-invasive technique in the detection of TRAS.