| Summary: | Five normal volunteers and twenty patients with angiographically proven IHD underwent rest/stress MRI examinations and myocardial scintigraphy for comparison. Five patients had coronary angioplasty and repeat MRI studies three months later. Five patients with Syndrome X were also studied with MRI. MPRI was significantly reduced in patients compared with normals (2.02 0.7 (mean SD), vs 4.21 1.16, p<0.02), with a significant negative correlation of MPRI with percent diameter stenosis of individual coronary lesions (r=-0.81, p< 0.01). MPRI in regions supplied by non-flow limiting lesions (<40% diameter stenosis) was significantly higher than regions supplied by stenoses of 'intermediate' (>40 % to 59%) severity, (2.80 0.77 and 1.93 0.38, p<0.02). Furthermore, MPRI predicted the functional status of the patients reasonably well after revascularisation in this small group. The sensitivity and specificity of quantitative MRI for the detection of global IHD in patients was comparable to thallium-201 scintigraphy (0.89 and 1.0 (sens/spec) vs 0.89 and 1.00) but both were superior to qualitative MRI (0.79 and 0.94). For identifying a significant coronary lesion the sensitivity of quantitative MRI was superior to both qualitative MRI and scintigraphy (0.82, 0.43, 0.75 respectively). The specificity of quantitative MRI was poorer than scintigraphy but similar to qualitative MRI (0.84, 0.89, 0.84). Finally, MPRI in patients with Syndrome X was reduced vs controls (2.17 0.72, p<0.01). Quantitative MRI perfusion studies can provide functional information to detect IHD in patients and assess adequacy of revascularisation. Furthermore, it may be able to provide insight into the mechanism of ischaemia in patients with Syndrome X.
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