Impact of MR angiography on the diagnosis and management of renal transplant dysfunction.

PURPOSE: To evaluate the impact of magnetic resonance angiography (MRA) on referring physicians' diagnoses and treatment of patients with renal transplant dysfunction. MATERIALS AND METHODS: Physicians of the renal transplant service at the authors' university hospital prospectively completed questionnaires before and after MRA was performed in the evaluation of renal transplants. The questionnaires asked physicians to estimate the probability (0%-100%) of their most likely diagnosis before and after receiving the imaging information. They were also asked to provide their anticipated and final treatment plans. The authors calculated the mean gain in diagnostic percentage confidence and the proportion of patients with changed initial diagnoses or anticipated management. A paired t test was used to assess statistical significance of the gains in diagnostic percentage confidence. RESULTS: Pre-MRA and post-MRA questionnaires were prospectively completed on 31 separate patients. The mean gain in diagnostic certainty percentage from MRA was 33% (95% CI, 19%-51%; P < .001). MRA changed physicians' initial diagnoses in 20 patients (65%; 95% CI, 47%-79%). Immediate clinical management changed in 16 patients (52%; 95% CI, 35%-68%). Invasive procedures were avoided in 12 patients (39%). CONCLUSION: MRA has considerable impact on referring physicians' diagnoses and treatment of patients with suspected renal allograft dysfunction.

Contrast-enhanced three-dimensional magnetic resonance angiography of the mesenteric vasculature.

The diagnosis and treatment of mesenteric occlusive disease is important due to the high morbidity and mortality associated with ischemia of the bowel. This article describes the application of magnetic resonance angiography (MRA) as a minimally invasive tool for diagnosing mesenteric and portal vascular disease. The techniques for three-dimensional (3D) contrast-enhanced MRA and flow measurement of the mesenteric circulation are described. Excellent image quality is obtained using sagittal contrast-enhanced 3D MRA of the aorta and proximal mesenteric vessels. Delineation of the small distal mesenteric branch vessels is still limited due to the finite spatial resolution of MRA. The application of MRA techniques to the diagnosis of mesenteric ischemia, revascularization, transplantation, and portal hypertension are demonstrated. Finally, the merits of various acquisition techniques and future contrast agents are discussed. MR angiography using intravenously administered contrast agents provides the clinician with a powerful, minimally invasive method for diagnosing mesenteric vascular disease.