A torção anexial é caracterizada por rotação parcial ou completa do ligamento suspensor do ovário e seu pedículo vascular correspondente, resultando em comprometimento vascular que pode culminar em infarto hemorrágico e necrose tecidual do ovário e da tuba uterina. Diante da gama de diagnósticos diferenciais de dor pélvica aguda, o diagnóstico é muitas vezes considerado desafiador, devendo o radiologista estar familiarizado com os principais achados de imagem. Nesse quesito, destacam-se os sinais característicos de torção anexial na ressonância magnética, incluindo aumento do volume ovariano com edema estromal, distribuição periférica de seus folículos, espessamento e edema da tuba uterina correspondente associados ou não à massa anexial – às vezes, fator predisponente – que se insinua para a linha média e, ainda, o clássico e patognomônico “sinal do redemoinho”. O objetivo deste ensaio é ilustrar e revisar os diferentes achados de torção ovariana detectados pela ressonância magnética.

Unitermos: Ressonância magnética; Ovário; Anormalidade de torção; Neoplasias ovarianas; Cistos ovarianos.

Objective:
To determine the accuracy of diffusion-weighted imaging (DWI) in identifying terminal ileitis in patients with Crohn’s disease.

Materials and Methods:
This was a retrospective study of 38 consecutive patients with Crohn’s disease who underwent magnetic resonance enterography with DWI in a 3.0 T scanner. The patients were divided into two groups, on the basis of colonoscopy and biopsy findings: active inflammation; and inactive disease. Apparent diffusion coefficient (ADC) values were determined, as were the magnetic resonance index of activity (MaRIA) and the Clermont score.

Results:
Of the 38 patients evaluated, 18 (47%) had active inflammation. The patients with active inflammation showed greater restricted diffusion, more pronounced mucosal edema, greater wall thickening, a higher MaRIA, and a higher Clermont score than did those with inactive disease. The level of interobserver agreement (intraclass correlation coefficient) was excellent for the MaRIA and the Clermont score, whereas it was substantial for the ADC values. For identifying colonoscopy-proven inflammation, the best ADC cut-off point was 2.1 × 10−3 mm2/s, which had a sensitivity of 88.8% and a specificity of 95.0%, whereas DWI presented an overall accuracy of 89.4%, with a sensitivity of 88.9% and a specificity of 90.0%.

Conclusion:
Visual analysis of the DWI sequence has good accuracy in detecting terminal ileitis in patients with Crohn’s disease. In addition, low ADC values have good sensitivity for detecting colonoscopy-proven inflammation. Keywords: Crohn’s disease; Diffusion magnetic resonance imaging; Inflammation; Ileitis; Intestine, small; Magnetic resonance imaging

Keywords: Crohn’s disease; Diffusion magnetic resonance imaging; Inflammation; Ileitis; Intestine, small; Magnetic resonance imaging.