Marco Carletto

The prognostic value of F-18 fluorodeoxyglucose bone marrow uptake in patients with recent diagnosis of multiple myeloma: A comparative study with Tc-99m sestamibi

Purpose: We assessed the prognostic value of F-18 fluorodeoxyglucose (FDG) uptake in the bone marrow of patients with multiple myeloma (MM) in comparison with Tc-99m methoxy-isobutyl-isonitrile (MIBI). Methods: The extent and intensity of FDG and MIBI uptake in the bone marrow of 18 patients with a recent diagnosis of MM were assessed by visual score and by calculating the mean SUV (mSUV) for FDG and the femora/thigh ratio (TG/BKG, [Target/Background ratio]) for MIBI images. These parameters were correlated with clinical indexes of disease using hemoglobin and beta-2-microglobulin levels and plasma cell infiltrate (PCI) percentage. The mean values of the visual score, mSUV, and TG/BKG levels were compared in patients deceased after a relatively short follow-up (n = 9; group A) and in patients with a longer survival or were alive at the end of the study (n = 9; group B). Results: Significant correlations of mSUV and TG/BKG values with PCI percentages and beta-2-microglobulin were found (P < 0.05). The extent of FDG and MIBI bone marrow uptake was greater in patients of group A (P < 0.01). Higher values of mSUV (P < 0.01) and TG/BKG (P < 0.05) were also observed in patients of group A. These results were consistent with the differences (not statistically significant) in hemoglobin, albumin, beta-2-microglobulin levels, and PCI percentages observed in the 2 groups. Conclusion: Our study demonstrates that an increase of FDG bone marrow uptake may predict a more aggressive disease, as much as MIBI uptake. Therefore, an additional analysis of FDG bone marrow images should be performed in patients undergoing PET studies during the initial staging of MM.

Missing sentinel lymph node in cutaneous melanoma

The American Society of Clinical Oncology guidelines recommend sentinel lymph node biopsy (SLNB) for all patients with melanoma tumors of intermediate thickness (between 1 and 4 mm). In case of patients with thick melanoma tumors (>4 mm), SLNB may be recommended as well, for staging purposes and to facilitate regional disease control. We report a case of an 82-year-old man, undergone excision of a cutaneous melanoma of the right thigh, which shows some limitation of SLNB in thick melanoma. Lymphoscintigraphy, performed as single-photon emission computed tomography/computed tomography (SPECT/CT), failed to identify the real sentinel lymph node, as tracer uptake was seen in A right inguinal node. Due to the presence on CT co-registered images of another suspicious node (with no radiopharmaceutical uptake) in the crural region, and considering the “high-risk” pathologic features of the removed primary lesion, a 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) staging scan was planned. PET/CT showed high metabolic activity in the suspected crural lymphadenopathy. Histopathology demonstrated massive invasion of the crural (“sentinel”) node and no metastatic cells in the inguinal node. This report highlights both the higher accuracy of lymphoscintigraphy, when performed as SPECT/CT and the potential utility of 18F-FDG PET/CT in regional staging.

Role of 18 F-FDG PET-CT in Vasculitis: A Prospective Study

Objective: Evaluate the diagnostic accuracy of PET in patients with fever of unknown origin (FUO) and in patients with suspected and/or proved large vessel vasculitis (LVV). Patients and methods: 72 patients (49 females, 23 males; mean age 63 y, range 23-82) were prospectively examined with PET between February 2010 and April 2013; 42 with suspected LVV, 15 with LVV during steroid therapy, and 15 with fever of unknown origin (FUO). Follow-up scans were performed in 19 patients. A semi-quantitative analysis [Vessel SUVmax]/[liver SUVmax] was performed to rate the disease in a 4-step system. PET scans were compared with temporal artery biopsy and MRI and/or angio-CT of a specific region. Results: Pathological 18 F-FDG (FDG) uptake was observed in 30/72 (42%) patients, and negative in 42/72 (58%) patients. In 42 patients with suspected LVV 9 (21%) were positive, and 33 (79%) negative; 11 (73%) of the 15 steroid-treated patients with LVV were positive, and 4 (27%) negative; 10 (67%) of the 15 patients with FUO were positive and 5 (33%) negative. PET had an overall sensitivity of 87% [95% confidence interval (CI) 79-95%], a specificity of 95% (95% CI 90-100%), a positive predictive value of 93% (95% CI 87-99%) and a negative predictive value of 91% (95% CI 84-97%). The diagnostic accuracy of PET was 92% (95% CI 85-98%). Conclusions: 18 F-FDG PET/CT especially that based on semi quantitative analysis is a sensitive and specific imaging tool for the diagnosis of LVV but also for therapy monitoring and follow up.