4D time‐resolved magnetic resonance angiography for noninvasive assessment of pulmonary arteriovenous malformations patency

Abstract

Purpose: To assess the capability of four-dimensional (4D) time-resolved magnetic resonance angiography (MRA) to assess pulmonary arteriovenous malformations (PAVMs) patency by analyzing pulmonary arterial and venous enhancement kinetics. ; dynamic scan time (temporal resolution) 1.2 seconds; total acquisition time 18.1 seconds for six dynamic datasets (6 Â 1.2 sec þ reference scan: 10.9 sec). All images were reviewed by two experienced radiologists. Image quality was rated on a qualitative 5-point scale (1: not assessable to 5: excellent). Signal value was measured on cross-sectional planes for the afferent arteries and efferent veins of the PAVM, and for normal reference healthy arteries and veins. The difference in time to peak for each coupled artery/vein (dTTPav) was calculated and compared with a MannWhitney test between PAVMs and reference vessels.Results: Mean image quality was 3.2 6 0.9. dTTPav was significantly smaller in PAVMs (0.15 6 0.76 sec) than in reference vessels (3.75 6 1.62 sec), P < 0.001.Conclusion: 4D-MRA is a promising tool for noninvasive assessment of PAVM patency.

Reperfusion Rates of Pulmonary Arteriovenous Malformations after Coil Embolization: Evaluation with Time-Resolved MR Angiography or Pulmonary Angiography

“…Follow-up examinations after successful coil embolization are important for detecting reperfusion, and DSA is the most sensitive modality used to examine blood flow through lesions because it detects simultaneous enhancements in the feeding artery and draining vein in reperfused PAVMs (8). In occluded PAVMs, as in normal pulmonary vessels, enhancements in the vein have been shown to occur within a few seconds of visualizing the artery (8).…”

“…Coils and detachable balloons were extensively used in PAVM embolization, and because there are currently no commercially available detachable balloons for the occlusion of PAVM, coils have become the main tool (7). Pulmonary angiography is considered the ideal imaging modality for reperfusion of a treated PAVM, but it is an invasive procedure (8). Although reperfusion rates ranging from 8% to 19% have been reported in the literature, all were obtained by measuring the size of the venous sac or draining vein by computed tomography (CT) (5,(9)(10)(11).…”

Pulmonary Arteriovenous Malformations: Current Technique of Transcatheter Embolization and Subsequent Management

“…However, the CT criteria reported in the literature included at least a 70% reduction in a draining vein and venous sac or their contrast enhancements [21,26,[35][36][37][38]. All of these CT criteria are indirect findings because it is often difficult to identify the recanalization itself through the embolic devices by CT due to metal artifacts [35].…”

2 Pulmonary arteriovenous malformations

“…These recommendations were not adopted universally due to radiation concerns (6,7,20,22,88,89), and in the light of data from Reference 13, are likely to be revised in the future. Alternate follow-up strategies used include magnetic resonance imaging, noting resolution is currently limiting (88,89) …”