The prognostic value of baseline (18)F-FDG PET/CT in steroid-naïve large-vessel vasculitis: introduction of volume-based parameters.

PURPOSE: The aim of this study was to analyse if the result of a baseline (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scan, in large-vessel vasculitis (LVV) patients, is able to predict the course of the disease, not only in terms of presence/absence of final complications but also in terms of favourable/complicated progress (response to steroid therapy, time to steroid suspension, relapses, etc.). METHODS: A total of 46 consecutive patients, who underwent (18)F-FDG PET/CT between May 2010 and March 2013 for fever of unknown origin (FUO) or suspected vasculitis (before starting corticosteroid therapy), were enrolled. The diagnosis of LVV was confirmed in 17 patients. Considering follow-up results, positive LVV patients were divided into two groups, one characterized by favourable (nine) and the other by complicated progress (eight), on the basis of presence/absence of vascular complications, presence/absence of at least another positive PET/CT during follow-up and impossibility to comply with the tapering schedule of the steroid due to biochemical/symptomatic relapse. Vessel uptake in subjects of the two groups was compared in terms of intensity and extension. To evaluate the extent of active disease, we introduced two volume-based parameters: "volume of increased uptake" (VIU) and "total lesion glycolysis" (TLG). The threshold used to calculate VIU on vessel walls was obtained by the "vessel to liver" ratio by means of receiver-operating characteristic analysis and was set at 0.92 × liver maximum standardized uptake value in each patient. RESULTS: Measures of tracer uptake intensity were significantly higher in patients with complicated progress compared to those with a favourable one (p < 0.05). Measures of disease extension were even more significant and TLG emerged as the best parameter to separate the two groups of patients (p = 0.01). CONCLUSION: This pilot study shows that, in LVV patients, the combined evaluation of the intensity and the extension of FDG vessel uptake at diagnosis can predict the clinical course of the disease, separating patients with favourable or complicated progress.

Breast cancer staging using technetium-99m sestamibi and indium-111 pentetreotide single-photon emission tomography.

We evaluated the clinical usefulness of single-photon emission tomography (SPET) with technetium-99m sestamibi and indium-111 pentetreotide in breast cancer staging. Fifteen patients with clinical and/or mammographic findings suggesting T1-2N0-1 breast cancer were studied. SPET images were acquired 20 min after 99mTc-sestamibi injection and 4 and 24 h after 111In-pentetreotide injection. Patients underwent surgery the day after the later 111In-pentetreotide acquisition. Pathological examination showed 16 tumours in the 15 patients, with one bilateral carcinoma. The mean tumour diameter was 18.7 mm. Metastatic axillary involvement was found in 6/16 tumours, with a mean of five metastatic nodes per axilla. Both tracers correctly identified 15/16 primary tumours and five of the six cases of metastatic axillary node involvement. No difference between the tracers was observed in breast cancer staging. 99mTc-sestamibi seems to be the better tracer in terms of physical characteristics, execution time and cost-effectiveness. Our data suggest the future possibility of using nuclear medicine imaging to avoid axillary dissection in patients with T1 breast cancer.

Assessment of mediastinal involvement in lung cancer with technetium-99m-sestamibi SPECT.

UNLABELLED: This study evaluated the clinical role of SPECT with sestamibi versus CT in the presurgical staging of lung cancer. METHODS: Forty-seven consecutive patients (44 men, 3 women; mean age 63.3 yr, range 49-82 yr) with clinical and radiological suspicion of lung cancer were enrolled in this study. Staging procedures including radiography, CT, fiberoptic bronchoscopy and sestamibi SPECT of the thorax. Radionuclide imaging was performed after intravenous injection of 740-925 MBq of sestamibi. In 36 patients a histological diagnosis was made, and these patients were evaluated for the study of mediastinal lymph node involvement. RESULTS: Mediastinal lymph node involvement was demonstrated in 11 of the 36 patients evaluated. Sestamibi SPECT correctly staged 10 of 11 patients with and 21 of 25 without mediastinal nodes, showing a diagnostic sensitivity of 91% and a specificity of 84%. Computed tomography gave 8 true-positive and 15 true-negative results, with a sensitivity of 73% and a specificity of 60%. Sestamibi SPECT results were also better than those of CT with regard to positive and negative predictive values and accuracy. CONCLUSION: The clinical role of sestamibi SPECT can be fully appreciated when the technique is used in selected patients, combined with CT or MRI, or both, to assess mediastinal involvement and avoid any invasive staging procedures.

Current role of gallium scan and magnetic resonance imaging in the management of mediastinal Hodgkin lymphoma.

BACKGROUND: A residual mediastinal mass after treatment represents a common diagnostic problem in the management of patients with Hodgkin lymphoma (HD). Conventional diagnostic radiology, computed tomography (CT), or ultrasonography (US) do not adequately reflect changes as fibrosis or necrosis. Gallium-67 (67Ga) imaging has been proven to be useful for the evaluation of HD in the mediastinum. The authors compared the ability of gallium scan and magnetic resonance imaging (MRI) to evaluate the mediastinal disease in the follow-up of patients with HD. METHODS: Thirty-four patients previously treated for HD were investigated with gallium scan, MRI, and all the other investigations to evaluate the mediastinal region. Sixteen patients were in restaging after treatment, and 18 were investigated for suspected radiologic recurrence in the mediastinum (follow-up, 9-75 months). The results of gallium scan and MRI were matched with clinical findings during the follow-up. RESULTS: A sensitivity of 85.7% for 67Ga and 92.8% for MRI was found, while the specificity was 100% for the scan and 80.6% for MRI. The predictive positive value that resulted was 100% for 67Ga and 68.4% for MRI. CONCLUSIONS: Both examinations were accurate in assessing the activity of residual masses in the mediastinum after treatment. 67Ga showed a lower sensitivity in comparison with MRI, but 67Ga frequently overestimates the presence of pathologic tissue. The authors acknowledge the complementary role of these two tests, but if only one of these examinations can be performed for logistic or economic reasons, then gallium scan represents the single most adequate diagnostic procedure.

[123I]IBZM uptake in metastatic melanoma.

In this report we describe our experience with [123I]IBZM ([123I]-(S)-2-hydroxy-3-iodo-6-methoxy-N-[(1-ethyl-2-pyrrolid inyl)methyl] benzamide), used to image the lesions in a female patient affected by metastatic melanoma. Marked uptake of [123I]IBZM in an area corresponding to a palpable lymph-nodal mass was observed in images collected 2 and 5 hours after i.v. tracer administration. Tumour to non-tumour ratios evaluated on planar maps were found to be 2.04 and 2.35, respectively. Surgical excision and histological examination of inguinal nodes confirmed the presence of melanoma lymph-nodal metastases. Although scintigraphy with radiolabelled [123I]IBZM is widely used for neuro-psychiatric disorders, we have found no reports in the literature of any application of this tracer in oncology. Even if the biological bases underlying the findings reported here remain unclear (although they are probably related to the neural crest origin of the melanocytes), the quality of imaging found suggests that this tracer may provide a new diagnostic tool for the imaging of melanoma tumours.