By Partha Ghosh, MD, Siemens Healthineers Molecular Imaging, Hoffman Estates, Illinois, USA
Data and images courtesy of Rigshospitalet, Copenhagen, Denmark
History
An elderly woman with history of ovarian carcinoma presented with abdominal pain and distention. Further clinical examination revealed gross ascites and abdominal tenderness. One hour following a 5.6 mCi (208 MBq) intravenous (IV) injection of Fludeoxyglucose F 18 (18F-FDG) Injection, the patient underwent a 5-minute, whole-body, single-bed PET/CT performed on Biograph Vision Quadra™.
Findings
Figures 1 to 6 show intense hypermetabolism within the peritoneal cavity with corresponding omental, mesenteric thickening, multiple macro- and micro-nodules along the bowel loops, peritoneal spaces, peri-colic gutters and liver dome, which show intense diffuse or nodular accumulation of 18F-FDG along with gross ascites, is typical of peritoneal carcinomatosis, which is very typical of ovarian carcinoma. 18F-FDG PET/CT defines the severity of peritoneal carcinomatosis and reflects the typical pattern of carcinomatous peritoneal deposition and serves as a baseline for post-chemotherapy assessment in this patient in which palliative chemotherapy in the only management choice.
Figure 1: PET MIP image shows multiple areas of intense 18F-FDG uptake in the peritoneal cavity especially in the right and left infracolic space as well as in the pelvis, omentum, liver dome, and left and right paracolic gutters, suggesting extensive peritoneal carcinomatosis from ovarian carcinoma. Axial contrast CT images at the levels of liver, kidneys, and aortic bifurcations show gross ascites with multiple nodular peritoneal depositions adjacent to the bowel loops and mesentery as well as thickening of omentum, omental caking, and enhancement. Axial PET and PET/CT slices show diffuse intense accumulation of 18F-FDG in the omentum corresponding to omental caking seen on CT. Hypermetabolic peritoneal tumor deposits visualized over the dome, right lateral, and posterior aspect of the liver with involvement of Morrison’s pouch as well as falciform ligament. Hypermetabolic nodular deposits are also visualized in the left paracolic gutter.
Discussion
Peritoneal carcinomatosis is common in ovarian carcinoma and colorectal carcinoma as well as in primary gastric carcinoma. Peritoneal involvement is a very significant adverse prognostic indicator in these malignancies.
18F-FDG PET/CT has been shown to have high sensitivity for detecting peritoneal malignant deposits which are often associated with intense hypermetabolism even when CT or MRI findings are equivocal and also when differentiation of malignant deposits from physiological bowel uptake is required.1 Peritoneal deposits on 18F-FDG PET/CT show a variety of patterns ranging from small focal deposits to diffuse involvement. Early peritoneal involvement is characterized by small irregular focal hypermetabolic deposits in the mesentery. More advanced peritoneal carcinomatosis shows typical tracer accumulation in the infracolic spaces, paracolic gutters, and posterior and inferior hepatic recesses, reflecting the typical pattern of the peritoneal space, which is related to flow of ascitic fluid.
This case shows advanced peritoneal carcinomatosis with the typical pattern of involvement of left and right infracolic spaces, pouch of Douglas, left and right paracolic gutters and liver dome, and posterior and inferior hepatic recesses, along with multiple macro- and micro-nodules in the small bowel mesentery as well as in the peri-cecal and peri-sigmoid spaces. This presentation is typical of advanced ovarian carcinoma-related peritoneal involvement.
Long axial field of view (FOV) PET/CT systems provide substantially higher sensitivity compared to standard FOV PET/CT systems. The 106-cm axial FOV along with ultra-fast time-of-flight (TOF) performance of Biograph Vision Quadra enables high image quality PET acquisition at fast imaging times. This is of relevance in patients with suspected peritoneal malignant deposition such as ovarian carcinoma where small peritoneal lesions can be detected with higher contrast due to the high performance of the large axial FOV.2 The 128-slice CT in the Biograph Vision Quadra system also provides high-quality contrast CT for visualization of omental and mesenteric thickening, macro- and micro-nodules for accurate localization and characterization of peritoneal hypermetabolic deposits, and differentiation from physiological uptake.
Conclusion
This case demonstrates how Biograph Vision Quadra achieves a 5-minute, low-dose, single-bed, whole-body 18F-FDG PET/CT delineation of peritoneal carcinomatosis in ovarian carcinoma.
Examination protocol
Scanner: Biograph Vision Quadra PET/CT
Prescribing information
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