Abnormal [18F]FDG PET/MRI findings in paraspinal structures of patients with suspected cerebrospinal fluid leak

Daehyun Yoon,Jessa Ballesteros Castillo,Sandip Biswal,Ian Richard Carroll,Yingding Xu,Ryan Penticuff,Peter William Cipriano

doi:10.1038/s41598-021-95056-w

Abstract

A combination of magnetic resonance imaging (MRI), computed tomography (CT), and radionuclide cisternography are typically used to locate a cerebrospinal fluid (CSF) leak. However, the site of leakage cannot be determined, making treatment more difficult. Therefore, more sensitive imaging tools are needed. A whole-body [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/MRI was conducted on six patients with suspected CSF leak and the resulting images were reviewed in comparison with those from six healthy controls. Paraspinal regions of focally increased uptake of [18F]FDG were quantified using maximum standardized uptake values (SUVmax) and compared to the SUVmax of corresponding regions in the healthy controls. All six patients with suspected CSF leak showed paraspinal regions of significantly greater [18F]FDG uptake compared to the corresponding areas in controls (P < 0.05). Two patients treated with local injections (epidural blood patches and/or epidural fibrin patches) on the site of abnormal PET/MRI findings reported temporary but significant improvement in symptoms. Our results suggest [18F]FDG PET/MRI is sensitive to abnormalities potentially due to suspected CSF leak, which are not necessarily visible on conventional MRI alone or by the standard-of-care imaging methods.

Highlights

Intra/extrathecal space extending into neuroforamina at C2 Paraspinal muscles at C6, T6-7, T8
While these two imaging modalities often are consistent in retrospective c omparison[17], this may reflect the common clinical scenario of using invasive computed tomography (CT) myelography much more frequently in patients with positive magnetic resonance imaging (MRI) than in patients with negative MRI—attempting to localize the source of leak suggested by findings seen on the subset of positive MRI
We recently presented initial findings from our s tudy[23], and here we describe in detail our early experience of [18F]FDG positron emission tomography (PET)/MRI of patients with chronic symptoms of suspected cerebrospinal fluid (CSF) leaks in comparison with healthy controls

Summary

Results

Abnormal [18F]FDG uptake was found on paraspinal muscles in 3 patients, interspinous ligament in 2 patients, osseous tissue in 3 patients, and fluid collection in one patient. The [18F]FDG S UVmax in lesions from the patient group showed a higher mean value than the corresponding areas from the control group in all tissue types (Table 2). The controls did not show areas of focally increased [18F]FDG uptake in these paraspinal regions as shown in an example case of Fig. 3b. The other patient whose blood-patch sites marginally included the PET/MRI abnormalities reported no symptomatic improvement

Discussion

Conclusion

Methods