Wang Sidi, Lädermann Alexandre, Chiu Joe, Nabergoj Marko, Ho Sean W L, Brigitte von Rechenberg, Bothorel Hugo, Lädermann Léo, Kolo Frank
Division of Orthopaedics and Trauma Surgery, La Tour Hospital, Meyrin, Switzerland.
Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Orthop J Sports Med. 2023 Feb 28;11(2):23259671231154275. doi: 10.1177/23259671231154275. eCollection 2023 Feb.
Traumatic rotator cuff tears can result in retraction of the tendon and may be associated with muscle edema, which may be confused with fatty infiltration as seen on magnetic resonance imaging (MRI).
To describe the characteristics of a type of edema associated with acute retraction of the rotator cuff tendon (termed "edema of retraction") and to highlight the risk of mistaking it with pseudo-fatty infiltration of the rotator cuff muscle.
Descriptive laboratory study.
A total of 12 alpine sheep were used for analysis. On the right shoulder, osteotomy of the greater tuberosity was performed to release the infraspinatus tendon; the contralateral limb acted as the control. MRI was performed immediately after surgery (time zero) and at 2 and 4 weeks postoperatively. T1-weighted, T2-weighted, and Dixon pure-fat sequences were reviewed for hyperintense signals.
Edema of retraction resulted in hyperintense signals around or within the retracted rotator cuff muscle on both T1- and T2-weighted imaging, but there was an absence of hyperintense signals on Dixon pure-fat imaging. This represented pseudo-fatty infiltration. Edema of retraction created a characteristic "ground glass" appearance of the muscle on T1-weighted sequences and was often found in either the perimuscular or intramuscular location of the rotator cuff muscle. Compared to time zero values, a decrease in the percentage of fatty infiltration was observed at 4 weeks postoperatively (16.5% ± 4.0% vs 13.8% ± 2.9%, respectively; < .005).
The location of edema of retraction was often peri- or intramuscular. Edema of retraction presented as a characteristic "ground glass" appearance of the muscle on T1-weighted sequences and led to a decrease in the fat percentage because of a dilution effect.
Physicians should be aware that this edema can result in a form of pseudo-fatty infiltration, as it is associated with hyperintense signals on both T1- and T2-weighted sequences, and it can be mistaken for fatty infiltration.
创伤性肩袖撕裂可导致肌腱回缩，并可能伴有肌肉水肿，在磁共振成像（MRI）上可能与脂肪浸润相混淆。
描述一种与肩袖肌腱急性回缩相关的水肿类型（称为“回缩性水肿”）的特征，并强调将其误诊为肩袖肌肉假脂肪浸润的风险。
描述性实验室研究。
共使用12只高山羊进行分析。在右肩，进行大结节截骨以松解冈下肌腱；对侧肢体作为对照。术后立即（零时间）以及术后2周和4周进行MRI检查。对T1加权、T2加权和 Dixon纯脂肪序列进行高信号检查。
回缩性水肿在T1加权和T2加权成像上均导致回缩的肩袖肌肉周围或内部出现高信号，但在Dixon纯脂肪成像上没有高信号。这表现为假脂肪浸润。回缩性水肿在T1加权序列上使肌肉呈现出特征性的“磨玻璃”外观，且常出现在肩袖肌肉的肌周或肌内位置。与零时间值相比，术后4周观察到脂肪浸润百分比降低（分别为16.5%±4.0%和13.8%±2.9%；P<.005）。
回缩性水肿常位于肌周或肌内。回缩性水肿在T1加权序列上表现为肌肉特征性的“磨玻璃”外观，并由于稀释效应导致脂肪百分比降低。
医生应意识到这种水肿可导致一种假脂肪浸润形式，因为它在T1加权和T2加权序列上均与高信号相关，且可能被误诊为脂肪浸润。
