Diffusion-weighted echo-planar imaging of the head and neck using 3-T MRI: Investigation into the usefulness of liquid perfluorocarbon pads and choice of optimal fat suppression method.

PURPOSE: To investigate whether image quality can be improved using liquid perfluorocarbon pads (Sat Pad) and clarify the optimal fat-suppression method among chemical shift selective (CHESS), water excitation (WEX), and short TI inversion recovery (STIR) methods in diffusion-weighted imaging (DWI) of the head and neck using 3-T magnetic resonance imaging. Correlations between results of visual inspection and quantitative analysis were also examined. MATERIAL AND METHODS: This study was approved by our Institutional Review Board and informed consent was waived. DWI was performed on 25 subjects with/without Sat Pad and using three fat-suppression methods (6 patterns). Image quality was evaluated visually (4-point scales and lesion-depiction capability) and by quantitative analysis (signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)). Two-way repeated-measures analysis of variance (ANOVA) was used to detect significant differences in scores of visual evaluation, SNR, and CNR. RESULTS: Mean visual evaluation scores were significantly higher with Sat Pad using STIR than without Sat Pad for all fat-suppression methods (P<0.05). DWI with Sat Pad using STIR tended to be useful for depicting lesions. DWI using STIR showed reduced W-SNR (W: whole area of depicted structure) and CNR (between semispinalis capitis muscle and subcutaneous fat) due to fewer artifacts and uniform fat suppression. CONCLUSION: Combining Sat Pad with STIR provides good image quality for visual inspections. When numerous artifacts are present and fat suppression is insufficient, higher SNR and CNR do not always provide good diagnostic image quality.

Postmortem computed tomography imaging in the investigation of nontraumatic death in infants and children.

OBJECTIVE: To determine the accuracy of postmortem computed tomography (PMCT) for the assessment of causes in nontraumatic deaths in children. STUDY DESIGN: We enrolled cases of nontraumatic deaths of infants and children who underwent PMCT at a single center. The presumed cause of death determined by PMCT was prospectively compared with the clinical and pathological diagnoses of deaths. RESULTS: Thirty-eight cases were enrolled for analysis. Among them, seven cases also underwent conventional medical autopsy. PMCT revealed an identifiable cause of death in accordance with the clinical diagnosis of death in 16 cases of the 38 cases (the concordance rate was 42%) and in accordance with the autopsy cause of death in four of the seven autopsy cases (the concordance rate was 57%). Among eight cases with unknown cause of death by clinical diagnosis, four cases (50%) were identified with cardiac tamponade as a cause of death (one case) and intracranial hemorrhage suggesting abuse (3 cases). CONCLUSIONS: PMCT seems to be a promising technique that might serve as a substitute for conventional medical autopsy and give us the complementary information to clinical diagnoses particularly in cases of child abuse. Larger multicenter trials are worthwhile to validate the general feasibility of PMCT.