Supine Breast MRI Using Respiratory Triggering.

RATIONALE AND OBJECTIVES: This study aims to evaluate if navigator-echo respiratory-triggered magnetic resonance acquisition can acquire supine high-quality breast magnetic resonance imaging (MRI). MATERIALS AND METHODS: Supine respiratory-triggered magnetic resonance imaging (Trig-MRI) was compared to supine non-Trig-MRI to evaluate breathing-induced motion artifacts (group 1), and to conventional prone non-Trig-MRI (group 2, 16-channel breast coil), all at 3T. A 32-channel thorax coil was placed on top of a cover to prevent breast deformation. Ten volunteers were scanned in each group, including one patient. The acquisition time was recorded. Image quality was compared by visual examination and by calculation of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image sharpness (IS). RESULTS: Scan time increased from 56.5 seconds (non-Trig-MRI) to an average of 306 seconds with supine Trig-MRI (range: 120-540 seconds). In group 1, the median values (interquartile range) of SNR, CNR, and IS improved from 11.5 (6.0), 7.3 (3.1), and 0.23 (0.2) cm on supine non-Trig-MRI to 38.1 (29.1), 32.8 (29.7), and 0.12 (0) cm (all P < 0.01) on supine Trig-MRI. All qualitative image parameters in group 1 improved on supine Trig-MRI (all P < 0.01). In group 2, SNR and CNR improved from 14.7 (6.8) and 12.6 (5.6) on prone non-Trig-MRI to 36.2 (12.2) and 32.7 (12.1) (both P < 0.01) on supine Trig-MRI. IS was similar: 0.10 (0) cm vs 0.11 (0) cm (P = 0.88). CONCLUSIONS: Acquisition of high-quality supine breast MRI is possible when respiratory triggering is applied, in a similar setup as during subsequent treatment. Image quality improved when compared to supine non-triggered breast MRI and prone breast MRI, but at the cost of increased acquisition time.

The congenital trigger thumb: is release of the first annular pulley alone sufficient to resolve the triggering?

The recognized treatment of persistent congenital trigger thumb (CTT) is surgical release of the flexor pollicis longus (FPL) tendon by transection of the first annular (A1) pulley at the thumb metacarpal head. Twenty-seven children with persistent CTT were operated between 2000 and 2004. The average age at surgery was 34 months. In 16 patients, the CTT appeared unilaterally and was the sole anomaly in the hand. The others suffered from either multiple hand abnormalities or another syndrome. In only 3 of the 16 thumbs (ie, 19%) division of just the A1 pulley at the metacarpal (MC) head was sufficient to relieve the triggering. In 11 thumbs (69%), a structure other than the sheath and distally from the A1 pulley, up to halfway the proximal phalangeal shaft (as a single entity), was discovered and had to be released also. A separate annular pulley, distal to the A1 pulley and other than the A2 pulley, was found in 2 cases (13%). In both cases, transection of this separate annular pulley alone sufficed. Complete release of the FPL was obtained in all, and none presented with postoperative complications at an average of 24 months' follow-up. Our clinical study suggests that a separate annular pulley system may exist, which has to be transected to allow for free FPL excursion in perhaps as many as 2 out of 3 CTTs. In our study group, this was not accompanied by complications.