Comparison of dynamic MR imaging of the breast and sestamibi scintimammography for evaluation of indeterminate mammographic lesions.

The aim of this study was to compare Tc-99m sestamibi scintimammography and dynamic contrast-enhanced MR imaging for the evaluation of indeterminate mammographic lesions. Forty patients with questionable mammographic findings were included in a prospective study. Thirty lesions were non-palpable. Mean lesion size was 1.6+/-0.7 cm (range 0.5-3.5 cm). Scintigraphy was considered as malignant when focal tracer accumulation was present. In MR imaging, lesions were classified according to their signal intensity time course: no enhancement or steady enhancement with low signal intensity (M0); steady enhancement with high signal intensity (M1); or rapid enhancement with plateau (M2) or washout (M3). Lesions classified as M2 or M3 were considered as suspicious for malignancy. Histopathologic evaluation was performed in 24 lesions. In 16 cases lesions were classified as benign from follow-up examinations (mean 24 months). Malignancies were proven in 14 patients (9 invasive carcinomas, 5 ductal carcinoma in situ). Sensitivity of MR imaging was 12 of 14 (86%) and sensitivity of scintimammography was 8 of 14 (57%). One of 26 benign lesions was false positive at MR imaging. Scintigraphy showed no false-positive results. In conclusion, magnetic resonance imaging provided high accuracy in evaluation of indeterminate mammographic lesions. Sensitivity of scintimammography was too low in detecting small carcinomas.

Persistent mirror movements: functional MR imaging of the hand motor cortex.

PURPOSE: To compare cortical areas involved in hand motor function in patients with persistent motor movements with those in healthy control subjects by using functional magnetic resonance (MR) imaging. MATERIALS AND METHODS: Nine patients (five patients with autosomal-dominant mirror movements, three with Kallmann syndrome, one with Wildervanck syndrome) and 10 healthy control subjects participated in the study. Functional MR imaging was performed at 1.5 T with a two-dimensional fast low-angle shot sequence. Participants were imaged while performing sequential finger-thumb opposition and during a rest period. RESULTS: During unimanual intentional movements, MR imaging in all control subjects showed increased signal intensity along the superior bend of the central sulcus contralateral to the moved hand. This increase was predominantly located in a region that included the medial part of the precentral gyrus. In contrast, MR imaging in patients with mirror movements showed bilateral activity in the medial region of the precentral gyrus. CONCLUSION: Bifurcations of the corticospinal tract may not be solely responsible for mirror movements. Bilateral activity of the primary motor cortex seems to play an additional role.