PURPOSE To determine the value of anesthetic injection during hip MR arthrography (anesthetic MRA) to differentiate between intra- and extra-articular pathology in patients with hip pain. MATERIALS AND METHODS This retrospective study was IRB-approved and HIPAA-compliant. We included 75 consecutive adult patients (46 women, mean age 38 ± 13 years) who were referred for MRA. All patients underwent a focused hip examination including active flexion, passive flexion, and passive flexion with internal and external rotation, immediately prior to injection. Anesthetic MRA was performed following fluoroscopically guided intra-articular injection of contrast mixed with anesthetic. Following the injection, the hip examination was repeated, and the pain response was recorded. Clinical records, including response to corticosteroid injections, physical therapy notes, and operative reports were reviewed for verification of intra- and extra-articular pathology as the source of hip pain (gold standard). The positive (PPV) and negative predictive values (NPP) of anesthetic MRA to differentiate between intra- and extra-articular pathology were calculated. RESULTS On MRI, 41 patients had only intra-articular and 5 patients only extra-articular pathology, while 29 patients had both, intra- and extra-articular pathology. Forty-three patients had pain relief and 32 patients had no pain relief after anesthetic injection. PPV of anesthetic MRA to detect intra-articular pathology was 91% and NPV was 67%. CONCLUSION Anesthetic MRA can be used as an adjunct to define the origin of hip pain. A positive response suggests intra-articular pathology which can be helpful to localize the source of pain in equivocal cases where both intra- and extra-articular pathology are evident on MRI.

中文翻译：

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髋部MR关节造影期间对麻醉剂注射做出反应以区分关节内和关节外病理的价值。

目的确定髋关节MR造影术（麻醉性MRA）中麻醉剂注射的价值，以区分髋关节疼痛患者的关节内和关节外病理。材料与方法这项回顾性研究获得IRB批准且符合HIPAA。我们纳入了75名连续接受MRA诊治的成年患者（46名女性，平均年龄38±13岁）。所有患者均在注射前立即接受了集中的髋部检查，包括主动屈曲，被动屈曲以及内外旋的被动屈曲。在荧光镜引导下关节腔内注射与麻醉剂混合的造影剂后，进行麻醉剂MRA。注射后，重复进行髋部检查，并记录疼痛反应。临床记录，包括对皮质类固醇注射的反应，回顾了物理治疗记录和手术报告，以验证关节内和关节外病理是否为髋关节疼痛的来源（金标准）。计算麻醉剂MRA区分关节内和关节外病理的阳性（PPV）和阴性预测值（NPP）。结果在MRI上，41例仅具有关节内病理，5例仅具有关节外病理，而29例同时具有关节内和关节外病理。麻醉注射后有43例患者疼痛缓解，而32例患者无疼痛缓解。用于检测关节内病理的麻醉MRA的PPV为91％，NPV为67％。结论麻醉MRA可作为辅助手段来确定髋关节疼痛的起源。