Università degli Studi di Milano, Facoltà di Medicina e Chirurgia, Scuola di Specializzazione in Radiodiagnostica, Via Festa del Perdono 7, 20122 Milan, Italy.
Eur J Radiol. 2012 Apr;81(4):e573-9. doi: 10.1016/j.ejrad.2011.06.048. Epub 2011 Jul 13.
To describe MRI features of fat necrosis of the breast.
Twenty-five lesions in 16 patients were retrospectively analyzed. MRI was performed due to equivocal findings at conventional imaging after surgical treatment of cancer (n=14) or during anticoagulant therapy (n=1), after focal mastitis treated with ductal resection (n=1). In the 15 patients with previous surgery MRI was performed after a median interval of 24 months, using short tau inversion recovery (STIR) and contrast-enhanced dynamic T1-weighted sequences. Signal-to-noise ratio (SNR) inside the lesion and surrounding healthy fat was calculated on both STIR and unenhanced T1-weighted images. Maximal lesion diameter was measured on STIR images. All lesions had final clinical and imaging assessment in favor of fat necrosis and negative clinical and imaging follow-up (21-40 months; median 24 months).
At STIR sequence, fat necrosis appeared as a "black hole", being markedly hypointense (median SNR=29) compared with surrounding fat (median SNR=95) (P<0.001), while no significant difference was found at unenhanced T1-weighted sequence. No significant correlation with time from treatment was found. Of 25 lesions, 15 showed ring enhancement, with continuous increase (n=10), plateau (n=2), or wash-out curve (n=3). The 11 enhancing lesions in the 8 patients with previous radiation therapy showed an initial enhancement higher than that of the 4 enhancing lesions in the 2 patients who did not, although the difference was not significant (P=0.104).
Fat necrosis of the breast exhibits a "black hole" sign on STIR images, allowing for an easier diagnosis in clinical practice.
描述乳腺脂肪坏死的 MRI 特征。
回顾性分析了 16 例患者的 25 个病灶。由于癌症手术后常规影像学检查结果不明确（n=14）或正在接受抗凝治疗（n=1）、导管切除治疗局灶性乳腺炎（n=1）而进行 MRI 检查。在 15 例有既往手术史的患者中，在中位数为 24 个月的时间间隔后进行 MRI 检查，使用短 tau 反转恢复（STIR）和对比增强动态 T1 加权序列。在 STIR 和未增强 T1 加权图像上计算病变内和周围健康脂肪的信噪比（SNR）。在 STIR 图像上测量最大病变直径。所有病变均经最终临床和影像学评估支持脂肪坏死，且无临床和影像学随访异常（21-40 个月；中位数 24 个月）。
在 STIR 序列上，脂肪坏死表现为“黑洞”，与周围脂肪相比呈明显低信号（中位数 SNR=29）（P<0.001），而在未增强 T1 加权序列上无明显差异。与治疗后时间无显著相关性。在 25 个病灶中，15 个病灶呈环形强化，表现为持续增强（n=10）、平台期（n=2）或廓清（n=3）。在 8 例有既往放疗史的患者中，11 个强化病灶的初始强化强度高于 2 例无放疗史患者的 4 个强化病灶，但差异无统计学意义（P=0.104）。
乳腺脂肪坏死在 STIR 图像上表现为“黑洞”征，有助于临床诊断。
