Diagnostic Value of FDG PET/MRI in Females With Pelvic Malignancy—A Systematic Review of the Literature

Abstract

Hybrid imaging with F-18 fludeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) has increasing clinical applications supplementing conventional ultrasound, CT, and MRI imaging as well as hybrid PET/CT imaging in assessing cervical, endometrial, and ovarian cancer. This article summarizes the existing literature and discusses the emerging role of hybrid PET/MRI in gynecologic malignancies. Thus, far, the published literature on the applications of FDG PET/MRI shows that it can have a significant impact on patient management by improving the staging of the cancers compared with PET/CT, influencing clinical decision and treatment strategy. For disease restaging, current literature indicates that PET/MRI performs equivalently to PET/CT. There appears to be a mild-moderate inverse correlation between standard-uptake-value (SUV) and apparent-diffusion-coefficient (ADC) values, which could be used to predict tumor grading and risk stratification. It remains to be seen as to whether multi-parametric PET/MRI imaging could prove valuable for prognostication and outcome. PET/MRI provides the opportunity for reduced radiation exposure, which is particularly relevant for a young female in need of multiple scans for treatment monitoring and follow-up. Fast acquisition protocols and optimized methods for attenuation correction are still evolving. Major limitations of PET/MRI remains such as suboptimal detection of small pulmonary nodules and lack of utility for radiation treatment planning, which pose an impediment in making PET/MRI a viable one-stop-shop imaging option to compete with PET/CT.

PET-MRI for evaluation of response to radiochemotherapy in patients with locally advanced cervical cancer

“…Diagnostic values are globally comparable with those in the literature 3 12. It seemed that addition of MRI to PET made it possible to better appreciate the contours, limits and possible extensions of contiguity than on PET-CT.…”

“…This was probably due to the excellent tissue contrast (injected T2 and T1FS sequences) of the MRI; much better than that of the same CT scan with intravenous contrast injection. However, this had no impact on the sensitivity, specificity, PPV, and NPV numbers, as in other works 12 19. In the preliminary study by Mongula et al, an improvement in diagnostic confidence was found in 80–90% of cases with PET and MRI 17…”

“…Moreover, despite interesting results on evaluation of tumor response, PET-CT with fluorodeoxyglucose (FDG) is not yet recommended for evaluating residual disease at the end of treatment in France 10 11. The feasibility of PET-MRI fusion has already been demonstrated 12–15. Indeed, one study using PET-MRI imaging for re-evaluation after radiochemotherapy was published in 2018.…”

Epithelioid leiomyoma of the uterus: A case report with magnetic resonance imaging findings

“…In contrast, previous studies reported that there were overlaps in ADC values between a uterine leiomyoma, such as cellular leiomyoma and bizarre leiomyoma, and uterine sarcoma, suggesting that DWIs alone are insufficient to establish a definite diagnosis [ [4] , [5] , [6] , [7] , [8] ]. Recently, several investigators have reported the high diagnostic capabilities of positron emission tomography (PET) using 2-[18F] fluoro-2-deoxy- d -glucose (FDG) for malignancies of various organs [ 9 , 10 ]. In cases where ADC values for the solid component of the tumor are not definitive for differentiating benign from malignant or borderline components, FDG-PET/computed tomography (CT) or FDG-PET/MRI could be useful.…”

Recent Imaging Updates and Advances in Gynecologic Malignancies

“…Hybrid imaging with Positron emission tomography-magnetic resonance imaging (PET-MRI) aims to combine the functional and quantitative metabolic data of PET with the high resolution anatomic and functional imaging properties of MRI in one combined or hybrid modality. It has the advantage of providing precise simultaneous evaluation of the primary gynecologic tumor and any possible metastasis with radiation exposure less than PET-CT by about 45% [ 41 ].…”