Evaluation of 18-F-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) as a staging and monitoring tool for dogs with stage-2 splenic hemangiosarcoma – A pilot study

Positron Emission Tomography-Computed Tomography (PET-CT) is routinely used for staging and monitoring of human cancer patients and is becoming increasingly available in veterinary medicine. In this study, 18-fluorodeoxyglucose (18FDG)-PET-CT was used in dogs with naturally occurring splenic hemangiosarcoma (HSA) to assess its utility as a staging and monitoring modality as compared to standard radiography and ultrasonography. Nine dogs with stage-2 HSA underwent 18FDG-PET-CT following splenectomy and prior to commencement of chemotherapy. Routine staging (thoracic radiography and abdominal ultrasonography) was performed prior to 18FDG-PET-CT in all dogs. When abnormalities not identified on routine tests were noted on 18FDG-PET-CT, owners were given the option to repeat a PET-CT following treatment with eBAT. A PET-CT scan was repeated on Day 21 in three dogs. Abnormalities not observed on conventional staging tools, and most consistent with malignant disease based on location, appearance, and outcome, were detected in two dogs and included a right atrial mass and a hepatic nodule, respectively. These lesions were larger and had higher metabolic activity on the second scans. 18FDG-PET-CT has potential to provide important prognostic information and influence treatment recommendations for dogs with stage-2 HSA. Additional studies will be needed to precisely define the value of this imaging tool for staging and therapy monitoring in dogs with this and other cancers.

正电子发射断层显像-计算机断层扫描（Positron Emission Tomography-Computed Tomography，PET-CT）常规用于人类癌症患者的分期与病情监测，目前在兽医学领域的应用也日益广泛。本研究针对罹患自发性脾脏血管肉瘤（splenic hemangiosarcoma，HSA）的犬只，采用18-氟脱氧葡萄糖（18FDG）标记的PET-CT成像技术，对比常规放射成像与超声检查，评估其作为癌症分期与监测手段的应用价值。本研究共纳入9例确诊为2期HSA的患犬，所有受试犬均在脾切除术后、化疗开始前接受18FDG-PET-CT检查。所有犬只在接受18FDG-PET-CT前均完成了常规分期检查，包括胸部放射成像与腹部超声检查。若18FDG-PET-CT检出常规检查未发现的异常征象，则告知犬只主人，并可选择在接受eBAT治疗后复查PET-CT。其中3只患犬于第21天接受了PET-CT复查。研究在2只患犬体内检出了常规分期手段未发现的异常病灶，结合病灶位置、影像学表现与临床转归，高度提示为恶性病变，分别为右心房肿块与肝脏结节。第二次扫描结果显示，上述病灶体积更大，代谢活性更高。18FDG-PET-CT可为2期HSA患犬提供重要的预后信息，并辅助调整治疗方案。未来仍需开展更多研究，以精准明确该影像学工具在该类及其他癌症患犬的分期与治疗监测中的具体应用价值。