Can Short Tau Inversion Recovery (STIR) Imaging Be Used as a Stand-Alone Sequence To Assess a Perianal Fistulous Tract on MRI? A Retrospective Cohort Study Comparing STIR and T1-Post Contrast Imaging.

INTRODUCTION: Perianal fistulas demand precise preoperative assessment for optimal surgical outcomes. MRI, using Short Tau Inversion Recovery (STIR) and T1-post contrast sequences, plays a crucial role in this evaluation.This retrospective cohort study compared STIR imaging's diagnostic efficacy with T1-post contrast sequences in identifying perianal fistulous tracts. The study investigated whether STIR imaging could serve as the sole diagnostic sequence, simplifying clinical practice. METHODS: In a tertiary care hospital, 100 patients underwent pelvic MRI for suspected perianal fistulas. Radiologists independently evaluated STIR and T1-post contrast sequences for internal openings, tract extent, distinction, abscess presence, and tract type. Sensitivity, specificity, area under the curve (AUC), and Cohen's kappa analysis were used for diagnostic assessment. RESULTS: STIR imaging showed notable sensitivity (79.8-97.9%) and specificity (100%) for identifying internal openings and tracts. Combined with T1-post contrast, diagnostic accuracy improved significantly, with near-perfect AUC values. Kappa values indicated moderate to substantial agreement between radiological assessments and clinical diagnosis. The combined sequences achieved 100% sensitivity and specificity for tract visualization. CONCLUSION: STIR imaging presents promise as a singular diagnostic tool for perianal fistulas, especially when combined with T1-post contrast sequences. While offering potential clinical diagnosis simplifications, further studies are warranted to validate its utility and ensure comprehensive diagnostic accuracy.

Differentiation of Leptomeningeal and Vascular Enhancement on Post-contrast FLAIR MRI Sequence: Role in Early Detection of Infectious Meningitis.

OBJECTIVE: To qualitatively and quantitatively differentiate leptomeningeal and vascular enhancement on Post-contrast Fluid Attenuated Inversion Recovery (PCFLAIR) sequence compared to post-contrast T1-weighted (PCT1W) sequence with fat suppression (FS) and evaluate its role in early detection of infectious meningitis. MATERIALS AND METHODS: Thirty-one patients with diagnosis of meningitis were evaluated with pre and post-contrast FLAIR and T1-weighted sequences with fat suppression (FS). Qualitative assessment was done by two observers for presence, absence or equivocal status of leptomeningeal enhancement. Further, quantitative estimation of single pixel signal intensities (SPSI) for meningeal and vascular enhancement was undertaken. A statistical comparison was performed using Kappa coefficient and t-test. RESULTS: The overall qualitative accuracy was 90.3% for PCFLAIR compared to 54.8% for PCT1W with FS sequence. PCFLAIR was found to be 100% accurate in the detection of tubercular and pyogenic meningitis and 70% accurate in the detection of viral meningitis while PCT1W with FS sequence showed the corresponding accuracy to be 76.2% and 0% respectively. Both observers rated PCFLAIR images better than PCT1W with FS at detecting meningitis (p<0.05). The quantitative assessment revealed that the SPSI difference between the average meningeal and vascular enhancement on PCFLAIR was significantly greater than that on PCT1W with FS sequence (t= 6.31, p<0.01). CONCLUSION: PCFLAIR sequence has insignificant component of vascular enhancement compared to meningeal enhancement. This makes meningeal inflammation easily discernable and aids in early detection of infectious meningitis.

Additional Merits of Two-dimensional Single Thick-slice Magnetic Resonance Myelography in Spinal Imaging.

OBJECTIVE: To validate the additional merits of two-dimensional (2D) single thick-slice Magnetic Resonance Myelography (MRM) in spinal imaging. MATERIALS AND METHODS: 2D single thick-slice MRM was performed using T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in addition to routine Magnetic resonance (MR) sequences for spine in 220 patients. The images were evaluated for additional diagnostic information in spinal and extra-spinal regions. A three-point grading system was adopted depending upon the utility of MRM in contributing to the detection of spinal or extra-spinal findings. Grade 1 represented no contribution of MRM while grade 3 would indicate that it was essential to detection of findings. RESULTS: Utility of MRM in spine was categorized as grade 3 in 10.9% cases (24/220), grade 2 in 21.8% (48/220) cases and grade 1 in 67.3% cases (148/220). Thus, the overall additional merit of MRM in spine was seen in 32.7% (72/220) of cases. Besides in 14.1% cases (31/220) extra-spinal pathologies were identified. CONCLUSION: 2D single thick-slice MRM could have additional merits in spinal imaging when used as an adjunct to routine MR sequences.