Purpose:To investigate the effect of a negative pressure fixation device on misregistration artifacts in contrast-enhanced (CE) MR subtraction images. Materials and Methods:Nine patients, two of which had been previously diagnosed with breast cancer, were examined with T2-weighted (T2-w) turbo spin-echo (TSE) and three-dimensional (3D) spoiled gradient-recalled echo (SPGR) CE dynamic MRI. Baselines images were subtracted from the dynamic images. A device consisting of two stiff plastic domes was placed on the breasts of each patient. Negative pressure of 27 to 37 mmHg within the domes was maintained. The patient was positioned prone in the coil without the device and imaged as a baseline. Subsequently, the patient was placed into the negative pressure domes and reimaged. One of the nine patients was also imaged supine to establish feasibility for this positioning. Results:With the use of the negative pressure fixation device, a reduction in misregistration artifact has been demonstrated in prone imaging. Patients reported improved comfort with the device and feasibility has been shown for supine imaging. Conclusion:The device was shown to be MRI-compatible and successfully applied in this pilot study, opening other avenues of exploration. Supine positioning for breast imaging makes possible better access for biopsy and intervention. Further modifications to the device are in order for this purpose and to eliminate motion due to breathing in the prone position.

Pure motor stroke (PMS) manifesting as distal weakness of a single extremity has rarely been described. The authors report a 59-year-old man with PMS who had primarily distal weakness of a single lower extremity, which to the authors' knowledge has not been previously described. Four days after onset, positive diffusion-weighted imaging confirmed that the small subcortical T2-weighted hyper-enhancing and nonenhancing T1-weighted hypo-intensity noted on magnetic resonance imaging (MRI) represented an acute PMS that was the cause of the patient's weakness. Increased awareness of this rare clinical presentation of PMS coupled with the promise of imaging the PMS with diffusion-weighted MRI should lead to earlier stroke intervention in these patients.

No abstract