Planning of catheter interventions for pulmonary artery stenosis: improved measurement agreement with magnetic resonance angiography using identical angulations.

OBJECTIVES

To evaluate the current disagreement between the gold standard X-ray angiography (XRA) and magnetic resonance angiography (MRA) for the measurement of peripheral pulmonary artery stenosis (PPAS).

BACKGROUND

MRA may help planning of catheter interventions for PPAS. However, there are sources of disagreement between XRA and MRA as measures are performed differently. We hypothesized that agreement may improve if identical angulation views are used.

METHODS

In this retrospective study, 17 patients were included. Four independent observers analyzed the pictures in three technique modalities: (1) XRA, (2) cross-sectional-MRA: reformatted to obtain the perpendicular cut-off view of the vessel, and (3) angulated-MRA: reformatted using the same angulations used in XRA. We measured: (a) minimal diameter at stenosis, (b) vessel diameter 1 cm proximal, and (c) 1 cm distal to the stenosis.

RESULTS

While in elliptical vessels cross-sectional-MRA provided both the larger and smaller diameter, XRA and angulated-MRA typically provided only the larger diameter due to projections. We found poor agreement between the smaller diameter in cross-sectional-MRA and XRA. XRA underestimate the diameter at the three locations (<15-22%). However, there was a good agreement between the larger cross-sectional-MRA diameter and XRA. This further improved if MRA images were reformatted with the identical angulations used in XRA (angulated-MRA).

CONCLUSIONS

Conventional cross-sectional-MRA measurements of PPAS only moderately agree with XRA. However, using identical angulations in MRA reduces the bias. Hence, MRA is a valuable tool for planning angulations and measurements of PPAS prior to catheter interventions.