Peripheral Bolus-Chase MR Angiography: Analysis of Risk Factors for Nondiagnostic Image Quality of the Calf Vessels–A Combined Retrospective and Prospective Study
June 25th, 2009 Posted by: admin
OBJECTIVE. The objective of our study was to evaluate the influence
of endogenous and exogenous risk factors on the rate of nondiagnostic
examinations of the calves in peripheral bolus-chase MR angiography (MRA).
SUBJECTS AND METHODS. Peripheral bolus-chase MRA runoff studies in
177 patients with peripheral arterial occlusive disease (PAOD) were
retrospectively assessed with regard to the rate of nondiagnostic image
quality due to substantial venous overlay in the calf arteries requiring
repeated MRA examinations. Logistic regression was used to analyze the rate of
nondiagnostic MRA examinations as a function of several endogenous and
exogenous risk factors and of the stage of PAOD. To probe the retrospective
data, 22 consecutive patients were prospectively included and underwent a
standard peripheral MRA examination if the probability of a nondiagnostic
examination was less than 50% based on the results of logistic regression;
otherwise, a hybrid MRA examination was ordered.
RESULTS. Nondiagnostic image quality of the calf arteries was found
in 53 patients (30%). The incidence increased with each stage of PAOD up to
39% for stage IV. For each increase in the stage of PAOD, the probability of
nondiagnostic image quality increased by a factor of 1.5561 (p =
0.0024). With an increasing number of risk factors, a significantly
(p = 0.0074) higher rate of nondiagnostic images was found.
CONCLUSION. Based on the retrospective statistical analysis of PAOD
stages and risk factors, selected patients can be triaged to undergo a
specific hybrid MRA technique and thus circumvent the occurrence of
nondiagnostic images and the need for repeated MRA examinations.
