Prolonged back pain attributed to suspected spondylodiscitis. The value of ¹8F-FDG PET/CT imaging in the diagnostic work-up of patients.

OBJECTIVE: This study aimed at investigating the diagnostic value of ¹8F-FDG PET/CT in cases of suspected spondylodiscitis after inconclusive results in initial diagnostic imaging. PATIENTS, METHODS: We analysed 38 consecutive cases of suspected spondylodiscitis (mean age: 67 ± 14 years) with chronic back pain referred to our Department during a four-year-period after inconclusive results in MRI or other conventional modalities. Clinical histories were retrospectively worked up and results of ¹8F-FDG PET/CT and MRI were analysed and related to the results of biopsy, blood culture and a one-year clinical follow-up. ¹8F-FDG PET/CT was analysed qualitatively by visual analysis and quantitatively. We measured the maximum standardized uptake value (SUV(max)) in the region of back pain and in a corresponding reference region (RR) in each patient and calculated a SUV(max-ratio). RESULTS: 22/38 patients had confirmed spondylodiscitis, while 16 were negative. ¹8F-FDG PET/CT established a correct diagnosis in 34 out of 38 patients by visual analysis. ¹8F-FDG PET/CT reached a sensitivity, specificity and accuracy of 81.8%, 100%, 89.5% and a PPV and NPV of 100% and 80%. MRI, performed in 27 patients reached a sensitivity, specificity and accuracy of 75%, 71.4%, 74.1% and a PPV and NPV of 88.2% and 50%. Patients with confirmed spondylodiscitis showed a significantly (p < 0.05) higher SUV(max) of 5.1 ± 1.9 and SUV(max)-ratio of 1.9 ± 0.8 than patients without it (SUV(max) (3.8 ± 1.5), SUV(max-ratio) (1.2 ± 0.3). CONCLUSION: ¹8F-FDG PET/CT provided diagnostic information in most patients with chronic back pain and suspected spondylodiscitis. It was helpful in establishing a correct diagnosis in challenging cases of spondylodiscitis with mostly unclear findings in previous MRI.

Isolated leptomeningeal infiltration of a primary CNS B-cell lymphoma diagnosed by flow cytometry and confirmed by necropsy.

BACKGROUND: The diagnosis of the isolated leptomeningeal involvement of a primary central nervous system B-cell lymphoma without parenchyma lesions may be difficult. Patients with leptomeningeal meningeosis lymphomatosa can present with various neurologic deficits. AIMS OF THE STUDY: To demonstrate the impact of cerebrospinal fluid (CSF) flow cytometry in the diagnosis of an isolated leptomeningeal manifestation of B-cell lymphoma by presenting an interesting case report. METHODS: Flow cytometric analysis of B-cell monoclonality of the CSF was performed as complementary diagnostic procedure in addition to CSF cytology. Final diagnosis was confirmed by necropsy. RESULTS: We suspected isolated leptomeningeal manifestation of B-cell lymphoma with palsy of the VI and VII cranial nerves in a 79-year-old male, because of mononuclear pleocytosis in CSF. Interestingly, the decisive diagnostic hint was given by implementation of flow cytometry of the CSF. Diagnosis was confirmed by postmortem autopsy. CONCLUSION: Our case shows that flow cytometry of the CSF in addition to conventional CSF cytology has the potential to accelerate diagnosis of lymphomeningeal infiltration of B-cell lymphoma.