Andrea Bianchi

Image interpretation criteria for FDG PET/CT in multiple myeloma: a new proposal from an Italian expert panel. IMPeTUs (Italian Myeloma criteria for PET USe)

PurposeFDG PET/CT is able to detect active disease in patients with multiple myeloma (MM) and can be helpful for staging and assessing therapy response, but no standard interpretation criteria have been proposed for the evaluation of FDG PET/CT in MM.MethodsA group of Italian nuclear medicine physicians and haematologists met to propose new visual interpretation criteria to standardize FDG PET/CT evaluation in MM patients (Italian Myeloma criteria for PET USe; IMPeTUs) and the reproducibility of these criteria was tested. This Italian multicentre protocol was set up as a subprotocol of EMN02, an international prospective multicentre trial of the European Myeloma Network. The criteria were agreed at multidisciplinary consensus meetings. They include a description of the metabolic state of the bone marrow (BM), number and site of focal PET-positive lesions, the number of osteolytic lesions, and the presence and site of extramedullary disease, paramedullary disease and fractures. A visual degree of uptake was defined for the target lesion and extramedullary lesions according to modified Deauville criteria. MM patients who had undergone FDG PET/CT at baseline (PET-0), after induction (PET-AI) and at the end of treatment (PET-EoT) were enrolled. The patients had been prospectively enrolled in EMN02 and their PET scans were a posteriori reinterpreted in a blinded independent central review process managed by WIDEN®. Five expert nuclear medicine physicians scored the scans according to the new criteria. A case was considered read when four out of the five reviewers completed the report. Concordance among reviewers on different metrics was calculated using Krippendorff’s alpha coefficient.ResultsA total of 17 consecutive patients were enrolled. On PET-0, the alpha coefficients for the BM score, the score for the hottest focal lesion, the number of focal lesions and the number of lytic lesions were 0.33 and 0.47, 0.40 and 0.32, respectively. On PET-AI, the alpha coefficients were 0.09 and 0.43, 0.22 and 0.21, respectively, and on PET-EoT, the alpha coefficients were 0.07, 0.28, 0.25 and 0.21, respectively. BM was generally difficult to score since grades 2 and 3 are difficult to discriminate. However, since neither of the two grades is related to BM myelomatous involvement, the difference was not clinically relevant. Agreement on focal lesion scores and on the number of focal lesions was good.ConclusionThe new visual criteria for interpreting FDG PET/CT imaging in MM patients, IMPeTUs, were found to be feasible in clinical practice.

Role of fluorine-flurodeoxyglucose positron emission tomography/computed tomography in preoperative assessment of anterior mediastinal masses

OBJECTIVE The purpose of the study was to explore the usefulness of fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET-CT) in the preoperative assessment of isolated anterior mediastinal lesions, especially in the planning of operative strategy (biopsy or upfront resection). METHODS During the last 36 months, 19 consecutive patients (10 males, mean age 54+/-16 years) underwent PET-CT in the preoperative work-up of isolated anterior mediastinal diseases. Maximal transverse diameter at CT and the postoperative histology and Masaoka staging for thymomas were collected and related to the maximum standardised uptake values (SUVs). Thymomas were divided into low-risk thymoma (LRT=A, AB and B1) and high-risk thymoma (HRT=B2, B3 and C). RESULTS There were 13 thymomas (six LRT and seven HRT), three lymphomas and three other primitive thymic tumours (one paraganglioma, two non-seminomatous germ cell tumours). In LRT, the mean SUV was 3.3+/-0.5 resulting significantly lower than HRT, 13.5+/-7 (p=0.009). The SUV in LRT was also significantly lower with respect to lymphoma, 12.4+/-4 (p=0.001), and the other primitive anterior mediastinal tumours, 8+/-0.8 (p=0.001). Between thymomas we found a significant correlation between Masaoka stage and SUV, r=0.718, p=0.006. No correlation was found between transverse diameters and SUV, r=0.141, p=0.6. CONCLUSIONS In our experience, low SUV (<5) is associated with LRT and minimal invasive thymoma (Masaoka stages I-II) and, therefore, susceptible to upfront surgery. For lesions with an infiltrative aspect on CT scan associated with a higher SUV (>5), an open biopsy is mandatory to exclude mediastinal lymphomas or, in case of HRT, to address a neoadjuvant treatment.

Breath Control Device with EKG monitoring (ABCDE) for routine imaging and therapy

Positron emission tomography (PET) has shown an increase in both sensitivity and specificity over computed tomography (CT) in particular for lung cancer. Motion artifacts in the fluoro-2-deoxy-d-glucose (FDG) PET images caused by respiration persists to be an important factor in degrading PET image quality and quantification. A lot of different methods have been developed to overcome this problem using breathing protocols or on-line monitoring systems. We constructed a respiratory gating device that monitor the breathing cycle through a pressure sensor and send the information to the electrocardiography (EKG) connector of our PET/CT system. In this work we will illustrate how this device, named ABCDE, works and discuss its use and limitations. ABCDE was tested on a small cohort of patients to prove the feasibility of the system in clinical practice. This preliminary investigation showed an improvement in the target-to-background ratio and a reduction in apparent lesion volume for all the patients we studied. This work was conducted as a proof of principle gating could improve the quantification and the resolution of PET images and that the system could be of use in clinical practice.