Stress MR imaging for evaluation of popliteal artery entrapment

Abstract

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young health volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.

Popliteal entrapment syndrome

“…[52][53][54][55] By using surgical confirmation of pathology as the reference standard and provocation catheter arteriography as the index test, 13 of 21 studies provided sufficient information to yield a mean estimate of sensitivity for provocation arteriography of 97% (median, 100%; range, 85%-100%). [22][23][24]27,30,33,36,37,39,40,[42][43][44] Similar estimates for other diagnostic modalities are given in Table II. One prospective study and five of seven retrospective case series on PAES recommended the use of cross-sectional magnetic resonance (MR) imaging (MRI)/MR angiography (MRA) or computed tomography (CT)/CT angiography in diagnosis because it allowed visualization of the common vas- cular (arterial stenosis, occlusion, aneurysmal change, and deviated course) and extravascular (abnormal muscle attachments and muscular hypertrophy) anatomic abnormalities implicated in arterial entrapment.…”

“…Functional popliteal artery entrapment was reported by nine of 30 studies, and this subset comprised a median 23% of entrapments (range, 6.25%-87.5%). 22,25,29,40,43,44,47,49,51 Of the remaining 21 studies, 14 provided sufficient detail about anatomic types to conclude that functional entrapment was not present in any of the reported patients. Although the most commonly used definition of functional popliteal entrapment was that proposed by Rignault et al 66 (compression due to muscular hypertrophy), two other interpretations of functional popliteal entrapment were encountered.…”

“…In the remaining 11 studies, no asymptomatic limbs were diagnosed with PAES. 22,23,26,32,37,39,43,44,46,48,50 Three of the four studies on PVES reported median age of 28 years (range, 27.6-43.6 years). Three of the studies that reported sex differentiation indicated a median 73% female predominance (range, 53%-100%).…”

Arteries and Nerves

“…It enables to locate the arterial stenosis as well as the anatomical relations between the artery and the adjacent muscle [ 26 ]. It has been demonstrated that stress MR imaging can improve the diagnosis of popliteal entrapment syndrome [ 27 ]. Therefore, the knee is imaged during active plantar fl exion against resistance, which increases the ability to detect a signal loss in the artery due to muscular compression [ 27 ].…”

“…It has been demonstrated that stress MR imaging can improve the diagnosis of popliteal entrapment syndrome [ 27 ]. Therefore, the knee is imaged during active plantar fl exion against resistance, which increases the ability to detect a signal loss in the artery due to muscular compression [ 27 ]. However, stress MR angiography is clinically diffi cult to perform and images frequently suffer from motion artifacts.…”