Utility of Standing Maneuvers during Abdominal Duplex Ultrasound Examination to Diagnose Median Arcuate Ligament Compression

Abstract

Introduction Median arcuate ligament compression (MALC) may present with abdominal pain as the result of dynamic compression of the celiac artery and the superior mesenteric artery (SMA). An asymptomatic patient may also demonstrate dynamic stenosis consistent with MALC on duplex examination. Duplex examination with maneuvers may differentiate fixed stenosis attributable to atherosclerosis (ASO) from dynamic stenosis caused by MALC. In MALC, elevated velocities normalize during deep inspiration. Performance of the Doppler examination with the patient standing may lead to improved diagnosis of MALC. Methods We performed a database query for all abdominal duplex examinations performed from January 1, 2007 to December 31, 2007 in which a standing (or seated) Doppler examination was reported. Studies were performed with a curved 5–2 MHz transducer (Philips iU22, Bothell, WA) with the patient in the fasting state. A peak systolic velocity (PSV) of ≥ 250 cm/sec in the celiac artery and a PSV of ≥ 275 cm/sec in the SMA were consistent with 70–99% stenosis. Results Ten patients were identified. Mean age was 51.2 years. A total of 60% of patients were female. Four patients presented for evaluation of abdominal pain and/or weight loss; six patients for other indications. Nine patients had increased PSV in the celiac artery at rest. The abnormality resolved with maneuvers in seven out of nine patients, consistent with MALC. In two patients, celiac artery PSV normalized with inspiration while they were supine; four patients in whom celiac artery velocity did not normalize with inspiration while they were supine had normal PSV while standing; one patient had normal celiac artery velocity while seated (no supine inspiration maneuvers performed); two patients had persistent celiac artery stenosis, likely because of ASO, although one normalized partially with standing. One patient had elevated velocities in the hepatic and splenic arteries that normalized with standing. Two patients had evidence of MALC of the SMA demonstrated with standing maneuvers. Conclusion Among patients with elevated velocities in the celiac artery and the SMA, repeated Doppler examination with the patient standing may demonstrate normalized velocities, consistent with MALC. The value of incorporating standing views into the abdominal duplex protocol to avoid false positive diagnoses of ASO merits prospective evaluation.

Subject Body Mass Index Affects Doppler Waveform in Celiac Artery by Duplex Ultrasound

“…[25] concluded that among patients with elevated velocities in the CA and SMA, repeated Doppler examination with the patient standing may demonstrate normalized velocities, consistent with CACS. Depending on Downing results [25] and our previous results [26] which showed that the best subject position to examine the CA is supine position and the best phase of respiration is during inspiration, we concluded that the CA should be examined in both phases of respiration and supine and upright body positions in subjects with possible CACS. In our present study we did not repeat the scanning during inspiration and with the subject in upright position as performed in our previous study [26] because we believe that the velocities in group A to be normalized.…”

Patient Position and Phase of Respiration Affect the Doppler Waveform in the Celiac Artery

“…The authors of some reports [20][21][22][23] have focused on the effect of respiration phase, especially expiration, as an essential factor affecting the fl ow velocity in the celiac artery, whereas the authors of a few other reports 24,25 in the literature put into consideration other factors affecting Doppler signal in the CA such as patient body position during the scanning. The present study was performed to study the effect not only the phase of respiration but the effect of body position in the Doppler signal in the CA during ultrasound Doppler scanning.…”

“…The caliber of the CA is larger during standing body position and while the patient is in the inspiration phase, where the vessel is less exposed to compression. Recently Downing et al 25 concluded that among patients with elevated velocities in the CA and SMA, repeated Doppler examination with the patient standing may demonstrate normalized velocities consistent with CACS. They emphasized that the value of incorporating standing views into the abdominal duplex protocol to avoid false-positive diagnoses of atherosclerosis merits prospective evaluation.…”

“…Depending on our results and Downing results, 25 we concluded that the CA should be examined in both phases of respiration and body position in a subject with possible CACS. In one phase, the artery should be scanned during supine position and expiration where the artery is exposed to highest level of compression.…”

“…19 Multiple factors might affect the peak systolic velocity in the CA causing CACS, such as the phase of respiration [20][21][22] and body position during ultrasound scanning. [23][24][25] Phase of respiration is a well-established factor that affects the CA during ultrasound scanning. Sproat et al 20 reported, with the use of ultrasound, real-time imaging of the celiac axis during respiration.…”