Hyperattenuation on non-enhanced CT and T2 hypointensity: an imaging pattern frequently associated with fibrous or smooth muscle-rich abdominal and pelvic lesions.

A dual imaging pattern of hyperattenuation on non-enhanced computed tomography and hypointensity on T2-weighted imaging is frequently encountered in various lesions. In the present review, we aimed to explore this imaging combination across a spectrum of abdominal and pelvic lesions to clarify its clinical implications.This pattern is commonly observed in lesions rich in fibrous or smooth muscle components, making it more frequently encountered in benign entities, including fat-poor angiomyolipomas, uterine leiomyomas, and tumors with predominant fibrous stroma. However, similar imaging findings may also be encountered in rare high-cellularity malignancies, selected systemic diseases, and lesions containing melanin, metal deposition, or thyroid tissue. Although not specific to a single disease, this imaging pattern offers valuable diagnostic clues for lesion characterization. When contrast-enhanced imaging is unavailable or contraindicated, combining non-enhanced computed tomography and T2-weighted imaging findings may help narrow the differential diagnosis. Despite its general association with benign lesions, this imaging phenotype requires careful exclusion of important pathologic mimics. Overall, integration with clinical information and other imaging findings remains essential for accurate interpretation.