Whole body magnetic resonance with diffusion weighted sequence with body signal suppression compared to (18)F-FDG PET/CT in newly diagnosed lymphoma.

Lymphomas are a heterogeneous group of lymphoid malignancies, which can be broadly divided into non-Hodgkin Lymphomas (NHL) and Hodgkin lymphoma (HL) that display different patterns of biological behavior and response to treatment. Their incidence is still increasing and for this reason they require a lot of effort in scientific research. The management of both NHL and HL follows well-established guidelines based on the initial staging assessment. Therefore an accurate staging is the basis for the selection of an appropriate therapeutic approach in order to prevent over or under treatment as well as to minimize morbidity related to the radio-chemotherapy regimens given. (18)F-FDG-PET is currently regarded as the reference standard imaging modality in the staging of the majority of lymphoma type, for evaluation of distribution of the disease by providing both functional and anatomic information in a single whole body examination. In particular its role is established in HL and high-grade NHL, confirmed also in Follicular Lymphoma, but its impact on the other histotypes remains to be demonstrated. Among the diagnostic tools currently available for a bio-molecular imaging assessment, of great interest is the Whole Body-Magnetic Resonance with DWIBS sequence (WB-MR/DWIBS), an emerging and promising functional whole body imaging modality to evaluate oncologic and non-oncologic lesions, resulting in images that remarkably resemble (18)F-FDG PET/CT studies. In our research study we evaluated the role of WB-MR/DWIBS, compared with (18)F-FDG-PET/CT in the initial staging of lymphomas, considering its impact on the management of these patients and how it could influence the therapeutic choice. We prospectively enrolled 27 consecutive patients with newly diagnosed lymphoma (13 HL, 14 NHL) histologically proven, who underwent (18)F-FDG-PET/CT and WB-MR/DWIBS (coronal T1-weighted, coronal STIR, axial sequences DWIBS) within 10 days from the diagnosis and before start the treatment. We evaluated the overall agreement between the two methods, the general agreement in evaluating both nodal and extra-nodal involvement and a specific site agreement according to lymph nodal basins or extra-nodal sites involvement. The agreement between the two diagnostic tools in relation to histological types (HL/NHL) and in relation to indolent and aggressive forms, within NHL histotypes, as well as in relation to the Ann Arbor stage was also evaluated. We also analyzed the role of WB-MRI/DWIBS and (18)F-FDG-PET/CT in bone marrow involvement detection by calculating their sensitivity and specificity, with bone marrow biopsy as the reference standard, and comparing them with McNemar test. A total of 85 lesions, nodal (74) and extra-nodal (11), were detected by (18)F-FDG-PET/CT. WB-MRI/DWIBS showed a total of 91 sites involved, (81) nodal and (13) extra-nodal lesions. The overall agreement between the two imaging modalities was very good (k=0.815; IC:0.739-0.890); however considering histotypes, the agreement comes down to good in evaluating NHL for both nodal and extra-nodal involvement (k=0.763, IC: 0.627-0.898; k=0.629, IC:-0.021-1.278). Considering indolent or aggressive forms the agreement between WB-MR/DWIBS and (18)F-FDG PET/CT findings was very good in aggressive forms while it appeared to be lower in indolent forms. Sensitivity and specificity of WB-MRI/DWIBS and (18)F-FDG PET/CT in bone marrow involvement detection were respectively: 100%and 100% vs. 50% and 96%. The switch from (18)F-FDG PET/CT to WB-MR/DWIBS in the AA Staging System resulted in an over-staging in 1/27 patient. The two methods were concordant in the staging in 26/27 patients (96%). In conclusion, our initial results show a good overall agreement between the two diagnostic tools. (18)F-FDG-PET/CT remains the gold standard for lymphoma staging, however WB-MRI/DWIBS can be useful in histotypes not (18)F-FDG-avid or in the evaluation of "critical" organs for (18)F-FDG PET/CT. The integrated information provided by metabolic and tissutal functional imaging can be complementary to assist hematologic decision of tailored patient's treatment.

Useful diagnostic biometabolic data obtained by PET/CT and MR fusion imaging using open source software.

In the last decade numerous attempts were considered to co-register and integrate different imaging data. Like PET/CT the integration of PET to MR showed great interest. PET/MR scanners are recently tested on different distrectual or systemic pathologies. Unfortunately PET/MR scanners are expensive and diagnostic protocols are still under studies and investigations. Nuclear Medicine imaging highlights functional and biometabolic information but has poor anatomic details. The aim of this study is to integrate MR and PET data to produce distrectual or whole body fused images acquired from different scanners even in different days. We propose an offline method to fuse PET with MR data using an open-source software that has to be inexpensive, reproducible and capable to exchange data over the network. We also evaluate global quality, alignment quality, and diagnostic confidence of fused PET-MR images. We selected PET/CT studies performed in our Nuclear Medicine unit, MR studies provided by patients on DICOM CD media or network received. We used Osirix 5.7 open source version. We aligned CT slices with the first MR slice, pointed and marked for co-registration using MR-T1 sequence and CT as reference and fused with PET to produce a PET-MR image. A total of 100 PET/CT studies were fused with the following MR studies: 20 head, 15 thorax, 24 abdomen, 31 pelvis, 10 whole body. An interval of no more than 15 days between PET and MR was the inclusion criteria. PET/CT, MR and fused studies were evaluated by two experienced radiologist and two experienced nuclear medicine physicians. Each one filled a five point based evaluation scoring scheme based on image quality, image artifacts, segmentation errors, fusion misalignment and diagnostic confidence. Our fusion method showed best results for head, thorax and pelvic districts in terms of global quality, alignment quality and diagnostic confidence,while for the abdomen and pelvis alignement quality and global quality resulted poor due to internal organs filling variation and time shifting beetwen examinations. PET/CT images with time of flight reconstruction and real attenuation correction were combined with anatomical detailed MRI images. We used Osirix, an image processing Open Source Software dedicated to DICOM images. No additional costs, to buy and upgrade proprietary software are required for combining data. No high technology or very expensive PET/MR scanner, that requires dedicated shielded room spaces and personnel to be employed or to be trained, are needed. Our method allows to share patient PET/MR fused data with different medical staff using dedicated networks. The proposed method may be applied to every MR sequence (MR-DWI and MR-STIR, magnet enhanced sequences) to characterize soft tissue alterations and improve discrimination diseases. It can be applied not only to PET with MR but virtually to every DICOM study.

Radiometabolic treatment of bone-metastasizing cancer: from 186rhenium to 223radium.

Skeletal metastases occur in many patients with different kinds of malignant tumors, especially in advance stage of breast cancer (in 47%-85% of patients), prostate cancer (33-85%), and lung cancer (32%-60%). The management of painful skeletal metastases is complicated and should be carried out by a multidisciplinary approach including conventional analgesics, antitumor therapy (chemo- and hormone therapy), osteoclast-inhibitory agents (bisphosphonates), corticosteroids, external-beam radiotherapy, surgery, and nuclear medicine therapy. The nuclear medicine therapy for palliation of pain from bone metastases is a systemic radionuclide therapy based on the use of radiopharmaceuticals. In several studies the efficacy of bone-seeking radiopharmaceuticals have been demonstrated in terms of pain reduction from diffuse skeletal metastases. In this review, we will summarize the current literature on bone-seeking radiopharmaceuticals for the treatment of painful bone metastases (Phosphorus-32, Strontium-89, Rhenium-186, Rhenium-188, Samarium-153, and Radium-223) and the combination therapy with biphosphonates and chemotherapy.

[Unusual sentinel lymph nodes detected by lymphoscintigraphy in cutaneous melanoma patients]. / Linfonodi sentinella "inusuali" alla linfoscintigrafia in pazienti con melanoma cutaneo.

Lymphoscintigraphy and radio-guided research of the sentinel lymph node is the most important investigation in the staging of patients with cutaneous melanoma, because it allows the identification of the lymphatic drainage pathways, not always predictable, and locate the sentinel node in classic basins and in "unexpected" regions. The aim of this study was to evaluate the incidence of cases of unusual sentinel nodes detected by lymphoscintigraphy and their prognostic significance in patients with cutaneous melanoma.

[Relapse of primary testicular non-Hodgkin's lymphoma detected by 18F-FDG-PET/CT]. / Recidiva muscolo-cutanea di linfoma non-Hodgkin primitivo del testicolo riconosciuta con 18F-FDG-PET/TC.

We report the case of a 62-year-old male with a history of primary testicular non-Hodgkin's lymphoma, treated with orchidectomy. After 14 months, the patient developed left leg swelling and pain, and was diagnosed and treated as having leg vein thrombosis. 18F-FDG-PET/CT showed a relapse of testicular lymphoma in the cutaneous muscle tissue of the left leg.