Comparison of Time-of-Flight-Magnetic Resonance Angiography From Silent Scan Magnetic Resonance Angiography in Depiction of Arteriovenous Malformation of the Brain.

OBJECTIVE: Silent magnetic resonance angiography (MRA) was compared with time-of-flight (TOF)-MRA in imaging of arteriovenous malformations (AVMs) of the brain. METHODS: Thirty-five consecutive patients with AVMs of the brain were included. Quantitative analyses were performed by measuring both signal-to-noise ratio and contrast-to-noise ratio of the nidus. Qualitative analysis (scores 1-4) was performed by evaluating depictions of feeding arteries and draining veins independently by 2 reviewers. RESULTS: Both signal-to-noise ratio and contrast-to-noise ratio in TOF-MRA were significantly higher than those in silent MRA. For both feeders and drainers, scores were significantly higher in silent MRA than in TOF-MRA for both reviewers. Interrater agreement was higher in silent MRA than in TOF-MRA. CONCLUSIONS: Silent MRA visualized feeders and drainers in AVMs significantly better than did TOF-MRA. Interrater agreement was also better in silent MRA.

T2-weighted IDEAL fast spin echo imaging of the brachial plexus: comparison with STIR.

BACKGROUND: Short TI inversion-recovery (STIR) imaging is widely used, but its signal-to-noise-ratio (SNR) is relatively low. Iterative decomposition of water and fat with echo asymmetric and least-squares estimation (IDEAL) imaging has demonstrated promising results in several areas. PURPOSE: To compare T2-weighted fast spin-echo IDEAL (T2W IDEAL-FSE) with STIR to determine which sequence is superior to image the brachial plexus. MATERIAL AND METHODS: The brachial plexus was imaged in 18 patients and six volunteers. The patients' diseases comprised of: suspected chronic inflammatory demyelinating polyneuropathy (CIDP), brachial plexus palsy of unknown origin, and suspected amyotrophic lateral sclerosis. Frontal partial MIP images were acquired. Image quality was qualitatively and independently scored by two radiologists on a three-point grading scale for noise, visibility of the nerve roots, and overall image quality. Inter-observer agreement of the rating by two readers was assessed. The SNR and contrast-to-noise-ratio (CNR) were quantitatively calculated, and differences between T2W IDEAL-FSE and STIR were compared. RESULTS: Qualitatively, each score for T2W IDEAL-FSE was significantly higher (P < 0.01) than that for STIR. Quantitatively, both SNR and CNR for T2W IDEAL-FSE (45.3 ± 12.6 and 27.1 ± 12.1, respectively) were significantly higher (P < 0.001) than those for STIR (17.4 ± 6.1 and 8.2 ± 4.7, respectively). CONCLUSION: T2W IDEAL-FSE could be used to replace STIR for visualization of the brachial plexus.

Augmented cerebral activation by lumbar mechanical stimulus in chronic low back pain patients: an FMRI study.

STUDY DESIGN: Cerebral activation by lumbar mechanical stimulus was investigated by functional magnetic resonance imaging in healthy subjects and patients with chronic low back pain (LBP). OBJECTIVES: To characterize the cerebral substrates of LBP, and to explore a possible pathologic pattern of cerebral activation in chronic LBP patients. SUMMARY OF BACKGROUND DATA: The cerebral substrates of LBP have been poorly defined in contrast to those of cutaneous somatic pain. METHODS: Eight healthy volunteers and 6 patients with idiopathic, chronic LBP were recruited. Each subject was placed in the prone position on a 3 Tesla MRI scanner, and stimulated by manual pressure with the tail of an air-filled, 20-mL syringe at 5 cm left of the fourth-fifth lumbar spinal interspace. Three blocks of 30-second painful stimulus, calibrated at either 3 or 5 on the 10-cm visual analog scale (VAS), were applied with intervening 30-second rest conditions during whole-brain echo-planar imaging. VAS of pain intensity and unpleasantness were evaluated after each session. Functional imaging was analyzed using a multisubject general linear model with Bonferroni multiple comparisons at P < 0.05. RESULTS: Pain thresholds were smaller (P < 0.05) and VAS of unpleasantness was larger in LBP patients than in healthy subjects. Activation was observed at the prefrontal, insular, posterior cingulate cortices (PCC), supplementary motor, and premotor areas predominantly in the right hemisphere, but not at the somatosensory cortices. LBP patients showed augmented activation compared with healthy volunteers specifically at the right insula, supplementary motor, and PCC. CONCLUSION: Chronic LBP patients showed increased tenderness at the lower back, higher aversive reaction to pain, and augmented LBP-related cerebral activation. The LBP-related activation is characterized by the absence of sensory-discriminative component and the involvement of PCC.