To Enhance or Not to Enhance? The Role of Contrast Medium ¹⁸F-FDG PET/CT in Recurrent Ovarian Carcinomas

• Main Authors: Michela Massollo, Francesco Fiz, Gianluca Bottoni, Martina Ugolini, Francesco Paparo, Cristina Puppo, Nicoletta Provinciali, Massimiliano Iacozzi, Vania Altrinetti, Angelina Cistaro, Manlio Cabria, Andrea DeCensi, Giorgio Treglia, Arnoldo Piccardo
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Medicina
• Subjects: PET/CT; contrast enhancement; ovarian cancer; FDG; relapse
• Online Access: https://www.mdpi.com/1648-9144/57/6/561

<i>Background and Objectives</i>: ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/X-ray computed tomography (PET/CT) represents the mainstay diagnostic procedure for suspected ovarian cancer (OC) recurrence. PET/CT can be integrated with contrast medium and in various diagnostic settings; however, the effective benefit of this procedure is still debated. We aimed to compare the diagnostic capabilities of low-dose and contrast-enhanced PET/CT (PET/ldCT and PET/ceCT) in patients with suspected ovarian cancer relapse. <i>Materials and Methods</i>: 122 OC patients underwent both PET/ldCT and PET/ceCT. Two groups of nuclear medicine physicians and radiologists scored the findings as positive or negative. Clinical/radiological follow-up was used as ground truth. Sensitivity, specificity, negative/positive predictive value, and accuracy were calculated at the patient and the lesion level. <i>Results</i>: A total of 455 and 474 lesions were identified at PET/ldCT and PET/ceCT, respectively. At the lesion level, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not significantly different between PET/ldCT and PET/ceCT (98%, 93.3%, 97.4%, 94.9%, and 96.9% for PET/ldCT; 99%, 95.5%, 98.3%, 97%, and 98% for PET/ceCT, <i>p</i> = ns). At the patient level, no significant differences in these parameters were identified (e.g., <i>p</i> = 0.22 and <i>p</i> = 0.35 for accuracy, in the peritoneum and lymph nodes, respectively). Smaller peritoneal/lymph node lesions close to physiological FDG uptake sources were found in the cases of misidentification by PET/ldCT. PET/ceCT prompted a change in clinical management in four cases (3.2%) compared to PET/ldCT. <i>Conclusions</i>: PET/ceCT does not perform better than PET/ldCT but can occasionally clarify doubtful peritoneal findings on PET/ldCT. To avoid unnecessary dose to the patient, PET/ceCT should be excluded in selected cases.