Background Gallium 68 (68Ga) pentixafor has emerged as a potential C-X-C chemokine receptor type 4 (CXCR4)-targeted radiotracer for neuroendocrine tumor, yet its application in Cushing disease remains uncertain. Purpose To assess the diagnostic accuracy and value of 68Ga-pentixafor PET/MRI in localizing adrenocorticotropic hormone (ACTH)-secreting pituitary tumors in Cushing disease. Materials and Methods A prospective single-center study was conducted from March 2023 to February 2024 in participants with Cushing disease scheduled for surgical pituitary tumor resection. All participants underwent preoperative 68Ga-pentixafor PET/MRI and contrast-enhanced MRI. Two radiologists and nuclear medicine physicians analyzed images. Surgical and histologic findings served as the reference standard. Diagnostic performance was compared using the McNemar test. The Wilcoxon signed rank test was used to compare the maximum standardized uptake value (SUVmax) between tumor and normal pituitary. Correlations between SUVmax and histopathologic or hormone characteristics were analyzed using the Spearman coefficient and logistic regression tests. Results A total of 43 participants (median age, 37 years [IQR, 31-49 years]; 35 female) were included, with 44 pituitary lesions identified after investigational imaging scans, 41 of which were confirmed as ACTH secreting. Sensitivity and diagnostic accuracy of 68Ga-pentixafor PET/MRI were 92.7% (38 of 41 lesions; 95% CI: 80.6, 97.5) and 88.6% (39 of 44 lesions; 95% CI: 76.0, 95.0), respectively, which were higher compared with that of contrast-enhanced MRI (78.0% [32 of 41 lesions; 95% CI: 63.3, 88.0] and 77.3% [34 of 44 lesions; 95% CI: 63.0, 87.2], respectively). Both techniques combined improved sensitivity to 100% (41 of 41 lesions; 95% CI: 91.4, 100.0) and accuracy to 95.5% (42 of 44 lesions; 95% CI: 84.9, 99.2) (P = .01). ACTH-secreting pituitary tumors exhibited a higher SUVmax than normal pituitary (3.9 vs 1.3, P < .001). The SUVmax exhibited a positive correlation with CXCR4 H-score (R = 0.5 [95% CI: 0.2, 0.7], P < .001) and ACTH levels (R = 0.4 [95% CI: 0.1, 0.6], P = .01). Conclusion 68Ga-pentixafor PET/MRI demonstrated high sensitivity in localizing ACTH-secreting pituitary tumors. 68Ga-pentixafor uptake was associated with CXCR4 expression and ACTH level. © RSNA, 2024 Supplemental material is available for this article.

中文翻译：

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使用 68Ga-pentixafor 进行 CXCR4 靶向 PET/MRI 对库欣病肿瘤定位的诊断准确性和价值。


背景 Pentixafor 镓 68 （68Ga） 已成为一种潜在的 C-X-C 趋化因子受体 4 型 （CXCR4） 靶向放射性示踪剂，用于治疗神经内分泌肿瘤，但其在库欣病中的应用仍不确定。目的 评价 68Ga-pentixafor PET/MRI 在定位库欣病分泌促肾上腺皮质激素 （ACTH） 的垂体瘤中的诊断准确性和价值。材料和方法： 2023 年 3 月至 2024 年 2 月在计划手术切除垂体瘤的库欣病参与者中进行了一项前瞻性单中心研究。所有参与者在术前接受了 68Ga-pentixafor PET/MRI 和造影剂增强 MRI。两名放射科医生和核医学医生分析了图像。手术和组织学检查结果作为参考标准。使用 McNemar 测试比较诊断性能。采用 Wilcoxon 符号秩检验比较肿瘤与正常垂体之间的最大标准化摄取值 （SUVmax）。使用 Spearman 系数和 logistic 回归检验分析 SUVmax 与组织病理学或激素特征之间的相关性。结果 共纳入 43 名参与者 （中位年龄，37 岁 [IQR，31-49 岁];35 名女性），在研究性影像学扫描后确定了 44 个垂体病变，其中 41 个被证实为 ACTH 分泌。68Ga-喷滴沙菌用于 PET/MRI 的敏感性和诊断准确性分别为 92.7%（41 个病灶中的 38 个;95% CI：80.6、97.5）和 88.6%（44 个病灶中的 39 个;95% CI：76.0、95.0），高于对比增强 MRI（78.0% [41 个病灶中的 32 个;95% CI：63.3、88.0] 和 77.3% [44 个病灶中的 34 个;95% CI：63.0， 87.2]。 两种技术相结合，将敏感性提高到 100% （41 个病灶中的 41 个;95% CI： 91.4， 100.0） 和 95.5% 的准确性 （44 个病灶中的 42 个;95% CI： 84.9， 99.2） （P = .01）。分泌 ACTH 的垂体瘤表现出比正常垂体更高的 SUVmax （3.9 vs 1.3，P < .001）。SUVmax 与 CXCR4 H 评分 （R = 0.5 [95% CI： 0.2， 0.7]，P < .001） 和 ACTH 水平 （R = 0.4 [95% CI： 0.1， 0.6]，P = .01）呈正相关。结论 68Ga-pentixafor PET/MRI 对定位分泌 ACTH 的垂体瘤表现出高敏感性。68Ga-pentixafor 摄取与 CXCR4 表达和 ACTH 水平相关。© RSNA，2024 年本文提供补充材料。