Imaging of common solid organ and bowel torsion in the emergency department

Imaging Features of Uncommon Entities That Manifest with Torsion

Torsion is the twisting of an object along the axis, and various structures (organs and tumors) in the body can twist. Torsion causes initial lymphatic and venous outflow obstruction, leading to congestive edema, enlargement, venous hemorrhagic infarction, and surrounding edema. It can also cause subsequent arterial obstruction depending on the degree of torsion, leading to ischemia, infarction, necrosis, gangrene, and surrounding inflammation. Therefore, in several cases of torsion, immediate surgical intervention is required to improve blood flow and prevent serious complications. Clinical manifestations of torsion are often nonspecific and can affect individuals of varying ages and sex. Imaging plays an important role in the early diagnosis and management of torsion. Multiple imaging modalities, including US, radiography, CT, and MRI, are used to evaluate torsion, and each modality has its specific characteristics. The imaging findings reflect the pathophysiologic mechanism: a twisted pedicle (whirlpool sign), enlargement of the torsed structures, reduced blood flow, internal heterogeneity, and surrounding reactive changes. The whirlpool sign is a definitive characteristic of torsion. In some cases, despite poor internal enhancement, capsular enhancement is observed on contrast-enhanced CT and MR images and is considered to be associated with preserved capsular arterial flow or capsular neovascularization due to inflammation. Radiologists should be familiar with the pathophysiologic mechanisms, clinical characteristics, and imaging characteristics of torsion in various structures in the body. Since other articles about common organ torsions already exist, the authors of this article focus on the uncommon entities that manifest with torsion. ©RSNA, 2024.

Qualitative and quantitative spermatic cord abnormalities at CT predict symptomatic scrotal pathology

PURPOSE

To evaluate quantitative and qualitative spermatic cord CT abnormalities and presence of unilateral or bilateral symptomatic scrotal pathology (SSP) at ultrasound.

METHODS

This retrospective study included 122 male patients (mean age 47.8 years) undergoing scrotal ultrasound within 24 h of contrast-enhanced CT (n = 85), non-contrast CT (NECT, n = 32) or CT-Urogram (n = 5). CECT quantitative analysis assessed differential cord enhancement using maximum Hounsfield unit measurements. Three fellowship trained body radiologists independently assessed qualitative cord abnormalities for both CECT and NECT. Qualitative and quantitative findings were compared with the presence of SSP. Reader performance, interobserver agreement and reader confidence were assessed for NECT and CECT. Quantitative cutoff points were identified which maximized accuracy, specificity, negative predictive value, and other measures.

RESULTS

SSP was present in 36/122 patients (29.5%). Positive cases were unilateral in 30 (83.3%) and bilateral in 6 (16.6%). At quantitative assessment, 25% differential cord enhancement had the highest diagnostic accuracy (88.9%), with 90.5% positive predictive value, 88.4% negative predictive value, 96.8% specificity, and 70.4% sensitivity. At qualitative evaluation, CECT reader performance was excellent (aggregate AUC = 0.86; P < .001); NECT was poorly discriminatory, although remained significant (aggregate AUC = 0.67; P = .002). Readers had significantly higher confidence levels with CECT (P < .001). Qualitative inter-observer agreement was high for both CECT and NECT (ICC = 0.981 and 0.963, respectively).

CONCLUSION

Simple quantitative assessment of differential cord enhancement is highly accurate and specific for SSP at CECT. Qualitative abnormalities at CECT and NECT are also both predictors of SSP, however, CECT significantly out-performs non-contrast exams.

Torsion of a Giant Antimesenteric Lipoma of the Ileum: A Rare Cause of Acute Abdominal Pain

Patient: Male, 67

Final Diagnosis: Torsion of a giant antimesenteric lipoma of the ileum

Symptoms: Acute abdomen

Medication: —

Clinical Procedure: En bloc segmental resection with end-to-end anastomosis

Specialty: Surgery