Magnetic resonance venous velocity mapping during intermittent pneumatic compression of the calf and foot.

OBJECTIVE

Assessment and optimization of intermittent pneumatic compression (IPC) devices for prophylaxis of deep vein thrombosis has previously used duplex ultrasound. The aim was to investigate novel magnetic resonance (MR) venous velocity mapping (VM) for IPC research and development.

METHODS

Twelve normal subjects were scanned in the supine position using realtime MR VM with sequential foot and calf IPC (120 mmHg) at 1.5 T. Measurements were taken in the popliteal vein at baseline using both cuffs and each cuff individually recording 60 seconds continuously. Temporal resolution was 310 ms per independent image, at 1 × 1 mm spatial resolution.

RESULTS

Peak velocity (V(p)) measurements: baseline, V(p) = 2.1 cm/second (range = 1.1-3.5); using both compression cuffs, V(p) = 41.5 cm/second (18.0-58.1); calf cuff alone, V(p) = 40.6 cm/second (18.1-62.2); foot cuff alone, V(p) = 7.9 cm/second (4.2-15.3). Flow volume measurements per compression cycle (F): baseline, F = 2.3 cm³ (0.5-11.4); both compression cuffs, F = 7.1 cm³ (2.5-24.6); calf cuff only, F = 7.1 cm³ (2.4-24.5); foot cuff only, F = 2.6 cm³ (0.9-10.7). The foot cuff contribution was insignificant when combined with the calf cuff (P < 0.01). The MR venous VM results were similar to those reported elsewhere using ultrasound.

CONCLUSION

This novel technique for MR venous VM can measure the realtime variations in venous blood flow during IPC.