Functional MRI of sensory motor cortex: comparison between finger-to-thumb and hand squeeze tasks.

BACKGROUND: An important imaging technique that has advanced decision-making for noninvasive preoperative evaluation is functional magnetic resonance imaging (fMRI). Preoperative fMRI imaging based on blood oxygenation level dependent (BOLD) fMRI is routinely used to map a variety of eloquent cortex brain functions such as language, visual, and sensory-motor regions. PURPOSE: The purpose of this study was to evaluate the regional volumes of sensory and motor cortex (SMC) activation by two widely used fMRI motor tasks: a simple hand squeeze (HS) versus a more complex finger-to-thumb (FTT) opposition. METHODS: Ten right-handed (five males; five females) subjects were studied using a block design BOLD fMRI technique at 1.5T. A region of interest analysis was performed in the right and left SMC following a HS and FTT task with the dominant right hand. RESULTS: Results show the total volume of motor and sensory activation for ipsilateral and contralateral areas for the FTT task was statistically larger than the HS task (P= .02). CONCLUSION: Due to the greater degree of activation of the SMC with the FTT task, we suggest use of this task over the HS task if a patient can adequately perform the more complex FTT task. The greater SMC activation using FTT task compared to the HS task was primarily due to an increase in activation in the post-central sensory cortex. There was less lateralization, and therefore a greater degree of bilateral SMC activation, in the FTT task compared to the HS task. These results show the importance of optimization and fMRI task selection for presurgical SMC mapping.

Correlation among on-call resident study volume, discrepancy rate, and turnaround time.

RATIONALE AND OBJECTIVES: With continued increase in imaging utilization and remote access image viewing technology, many academic radiology departments are presented with the suggestion to supplement on-call resident preliminary reports with an outsourced attending interpretation. This idea is often brought to administrative attention because of the subjective impression that outsourced studies will benefit from significantly faster interpretation times and lower discrepancy rates, especially when study volume is high. We attempt to retrospectively analyze on-call resident studies at a busy Trauma I university hospital and establish whether a statistical correlation exists among study volume, discrepancy rate, and turnaround time. MATERIALS AND METHODS: On-call computed tomography and ultrasound studies between January 2008 and June 2008 were retrospectively reviewed by blinded staff radiologists for discrepancies between preliminary and final reports. A correlation analysis between discrepancy rate and study volume per shift was performed. In addition, correlation analysis between volume per shift and interpretation time was also performed. RESULTS: A total of 1133 studies were reviewed. The major discrepancy rate is 1.85% with average turnaround time of 28.5 minutes. The correlation coefficient between major discrepancy rate and study volume is 0.35. The correlation coefficient between interpretation time and study volume is 0.29. CONCLUSION: Our large retrospective review of preliminary reports from different residents reveals no significant correlation among discrepancy rate, turnaround time, and study volume. The overall discrepancy rate is similar to that reported by other studies. Other institutions can perform this study to analyze whether their volume and resident performance warrants supplemental assistance before depriving residents of the educational benefits the independent on-call experience affords.