Tumour stage has been demonstrated to have prognostic significance in canine oral malignant melanoma (OMM). Various evaluation techniques of positron emission tomography/computed tomography (PET/CT) have been reported for staging of head-and-neck tumours in people, but canine-specific data are limited, and reports for CT accuracy have been variable. In this prospective study, the head/neck of client-owned dogs with cytologically or histologically diagnosed OMM were imaged with ¹⁸Fluorine-fluorodeoxyglucose (¹⁸F-FDG) PET/ CT. Bilateral mandibular lymphadenectomy was performed for histopathologic assessment. Two evaluation techniques for CT and PET were applied by four independent observers. CT evaluation utilized both a standardized grading scheme and a subjective clinical interpretation. PET evaluation was first performed solely on ¹⁸F-FDG-uptake in lymph nodes compared to background on a truncated scan excluding the oral cavity. Subsequently, the entire head/neck scan and standardized uptake value (SUV) measurements were available. Receiver operating characteristic analysis was performed with histopathology as gold standard. Twelve dogs completed the study and metastatic OMM was identified in six mandibular lymph nodes from five dogs. Of the CT-interpretation techniques, use of clinical grading performed best (sensitivity = 83% and specificity = 94%). Both PET techniques resulted in 100% sensitivity, but primary tumour site evaluation and use of SUV increased specificity from 78% to 94%. The SUVmax cut-point, 3.3, led to 100% sensitivity and 83% specificity. In this population of dogs, PET appeared to be highly sensitive but at risk of being less specific without use of appropriate parameters and thresholds.

中文翻译：

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18F-FDG正电子发射断层扫描和计算机断层扫描检测犬口腔恶性黑色素瘤淋巴结转移的准确性评估


肿瘤分期已被证明对犬口腔恶性黑色素瘤（OMM）具有预后意义。据报道，正电子发射断层扫描/计算机断层扫描 (PET/CT) 的各种评估技术可用于人类头颈肿瘤的分期，但犬类特异性数据有限，而且 CT 准确性的报告也各不相同。在这项前瞻性研究中，客户拥有的经细胞学或组织学诊断为 OMM 的狗的头部/颈部采用¹⁸氟-氟脱氧葡萄糖 ( ¹⁸ F-FDG) PET/CT 进行成像。进行双侧下颌淋巴结切除术以进行组织病理学评估。四名独立观察员应用 CT 和 PET 两种评估技术。 CT 评估同时采用标准化分级方案和主观临床解释。首先仅对淋巴结中的¹⁸ F-FDG 摄取进行 PET 评估，并与不包括口腔的截断扫描的背景进行比较。随后，可以进行整个头/颈部扫描和标准化摄取值（SUV）测量。以组织病理学作为金标准进行受试者操作特征分析。 12 只狗完成了这项研究，并在 5 只狗的 6 个下颌淋巴结中发现了转移性 OMM。在 CT 判读技术中，使用临床分级效果最好（敏感性 = 83%，特异性 = 94%）。两种 PET 技术的敏感性均为 100%，但原发肿瘤部位评估和 SUV 的使用将特异性从 78% 提高到 94%。 SUVmax 切点 3.3 导致 100% 的敏感性和 83% 的特异性。在这个狗群中，PET 似乎高度敏感，但如果不使用适当的参数和阈值，则有可能降低特异性。