Quick Evaluation of Lower Leg Ischemia in Patients with Peripheral Arterial Disease by Time Maximum Intensity Projection CT Angiography: A Pilot Study

Abstract

Background: The purpose of this study is to evaluate the new method of time maximum intensity projection (t-MIP) which was postprocessed from dynamic computed tomographic angiography (dyn-CTA) in diagnosing peripheral arterial disease (PAD). Methods: A population of 34 patients with known PAD was examined with a combined CTA protocol consisting of an s-CTA of the lower extremity and a dyn-CTA scan of the calves. For each lower leg, t-MIP images consisting of the MIP0 (sagittal MIP), and MIP+θ (45degree lateral MIP), MIP-θ (-45degree lateral MIP) were automatically generated from dyn-CTA. An objective evaluation of vascular CT attenuation of the best enhancement phase of dyn-CTA and t-MIP was measured; subjective evaluation of vessel stenosis and occlusion with a score was assigned for t-MIP and s-CTA. A comparison between the CT attenuation of t-MIP and dyn-CTA was made, so was the runoff score of t-MIP and s-CTA.Results: The CT attenuation of t-MIP CTA of three vascular segments from 68 lower extremities was higher than that of the best enhancement phase of dyn-CTA and s-CTA, with statistical significant difference at posterior tibial artery and fibular artery (all p＜0.05) . There were strong correlations (r ≥0.75, p < 0.05) of runoff scores between t-MIP and s-CTA. Conclusions: There is potential clinical application of t-MIP for assisting with the diagnosis of lower leg vascular stenosis in dyn-CTA with reliable diagnostic accuracy and convenient immediacy.

A New General Maximum Intensity Projection Technology via the Hybrid of U-Net and Radial Basis Function Neural Network

“…Based on these considerations, we assumed that the biggest function of MIP technology is to display the stenosis, dilation, and morphological direction of blood vessels or trachea. By now, the developed post processing-based high-performance software can display high-quality MIP images well [18]. If the three-dimensionality of the image needs to be displayed, the volume rendering (VR) method can replace the projection method.…”