Motion of the distal renal artery during three‐dimensional contrast‐enhanced breath‐hold MRA

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Abstract
Purpose To study the potential detrimental effects of renal motion on breath‐hold three‐dimensional contrast‐enhanced (CE) magnetic resonance angiography (MRA). Materials and Methods A computer model simulating linear motion was applied to MRA pulse sequences. Subsequently, to study whether renal motion was present, 24 patients being evaluated for possible renovascular hypertension underwent a breath‐hold nonenhanced single slice two‐dimensional dynamic turbo field‐echo magnetic resonance imaging (MRI) scan with a typical duration of 32 seconds. This sequence was followed by breath‐hold three‐dimensional CE renal MRA. CE‐MRA images were evaluated by two independent observers. Results The computer model revealed linear renal motion to cause artifacts. The severity of these artifacts correlated with velocity. Significant (P < 0.001) near linear cranial motion of the kidneys and diaphragm during a sustained breath‐hold was found for the right kidney, left kidney, right diaphragm, and left diaphragm (0.26 ± 0.21 mm/second, 0.25 ± 0.23 mm/second, 0.43 ± 0.43 mm/second, and 0.29 ± 0.33 mm/second [mean ± SD], respectively). CE‐MRA images showed artifacts of the distal renal artery that corroborated the computer model findings. Conclusion The observed cranial motion of the kidneys during a breath‐hold adversely affects distal renal artery image quality on three‐dimensional CE‐MRA and jeopardizes reliable clinical evaluation. Shortening scan time may be beneficial for decreasing image degradation caused by this phenomenon. J. Magn. Reson. Imaging 2002;16:685–696. Published 2002 Wiley‐Liss, Inc.