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Gadolinium-enhanced magnetic resonance angiography in renal artery stenosis: comparison with digital subtraction angiography
YM Law,
KH Tay,
YU Gan,
FK Cheah,
BS Tan
Department of Diagnostic Radiology,
Singapore General Hospital, Outram
Road, Singapore 169608
OBJECTIVES. To evaluate the accuracy of gadolinium-enhanced magnetic
resonance angiography in assessing renal artery stenosis
compared to catheter digital subtraction angiography.
DESIGN. Retrospective study.
SETTING. Singapore General Hospital.
PATIENTS. Records of patients who underwent magnetic resonance
angiography as well as digital subtraction angiography for
assessment of renal artery stenosis from January 2003 to
December 2005 were reviewed.
RESULTS. There were 27 patients (14 male, 13 female) with a mean age
of 62 (range, 44-77) years. There were 10 patients with renal
transplants; their native renal arteries were not evaluated. Each
of the two experienced interventional and body magnetic
resonance radiologists, who were blinded to the results,
reviewed the digital subtraction angiography and magnetic
resonance angiography images respectively. Digital subtraction
angiography was used as the standard of reference. A total of
39 renal arteries from these 27 patients were evaluated. One of
the arteries was previously stented and could not be assessed
with magnetic resonance angiography due to severe artefacts.
Of the remaining 38 renal arteries, two were graded as normal,
seven as having mild stenosis (<50%), eight as having moderate
stenosis (>=50% but <75%), and 21 as having severe stenosis
(>=75%). Magnetic resonance angiography and digital subtraction
angiography were concordant in 89% of the arteries; magnetic
resonance angiography overestimated the degree of stenosis in
8% and underestimated it in 3% of them. In the evaluation of
clinically significant renal artery stenosis (>=50%) with magnetic
resonance angiography, the overall sensitivity, specificity, positive
predictive value, and negative predictive value were 97%, 67%,
90%, and 86% respectively. The sensitivity and specificity of
magnetic resonance angiography in transplant renal artery
stenosis was 100%.
CONCLUSION. Our experience suggested that gadolinium-enhanced magnetic
resonance angiography is a sensitive non-invasive modality
useful in the assessment of clinically significant renal artery
stenosis.
Hong Kong Med J 2008;14:136-41
Key words: Angiography, digital subtraction;
Gadolinium; Magnetic resonance
angiography; Renal artery obstruction;
Sensitivity and specificity
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