Heart Osteosarcoma Presenting as Infective Endocarditis: A Case Report of a Patient With a Cardiac Pacemaker and Triple Malignancies.

Primary and metastatic cardiac sarcomas represent rare neoplasms with a variable clinical course. We present a rare case of an 84-year-old man with a cardiac pacemaker and heart osteosarcoma, hepatocellular and prostatic carcinoma, who was admitted with suspected symptoms of infective endocarditis. Findings of cardiac osteosarcoma in a patient with a pacemaker and three malignancies have not been reported before in the literature.

18F-FDG-PET/MR increases diagnostic confidence in detection of bone metastases compared with 18F-FDG-PET/CT.

PURPOSE: The aim of this study was to compare detection, lesion conspicuity and reader confidence of F-fluorodeoxyglucose (F-FDG)-PET/MR and F-FDG-PET/computed tomography (CT) in patients with F-FDG avid bone metastases. MATERIALS AND METHODS: In this prospective study, a total of 30 PET/CT and PET/MRI data sets were performed in 24 patients. Each examination was evaluated for the presence of PET-positive bone lesions consistent with metastatic involvement. Conspicuity of PET-positive bone lesions was evaluated on the corresponding PET/CT and PET/MR images and compared using the Wilcoxon signed-ranks test. Reader confidence was determined to evaluate whether PET/CT or PET/MR was more useful for the assessment of the bone metastases and was compared using Student's t-test. RESULTS: Overall, in both examinations, PET/CT and PET/MRI detected 86 F-FDG-positive bone lesions. On all 30 PET/MRI examinations, at least one morphological correlate for F-FDG-positive bone lesions was found on the MR component (82 out of 86 lesions). PET/CT imaging allowed identification of corresponding structural changes on the CT component in 23 out of 30 studies (65 out of 86 lesions). In lesion-by-lesion analysis, the mean lesion conspicuity was significantly better on T1 fat MR imaging compared with CT imaging (P=0.005). In seven out of 30 studies, a significant increase in reader confidence of PET/MRI compared with PET/CT was found. CONCLUSION: PET/MRI offers higher reader confidence and improved conspicuity in bone metastases compared with PET/CT. However, the overall detection rate was not different. The highest possible clinical impact of PET/MRI appears to be in patients with limited, early bone metastatic disease.

Final Results of a Prospective Evaluation of the Predictive Value of Interim Positron Emission Tomography in Patients With Diffuse Large B-Cell Lymphoma Treated With R-CHOP-14 (SAKK 38/07).

PURPOSE: Our main objective was to prospectively determine the prognostic value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) after two cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone given every 14 days (R-CHOP-14) under standardized treatment and PET evaluation criteria. PATIENTS AND METHODS: Patients with any stage of diffuse large B-cell lymphoma were treated with six cycles of R-CHOP-14 followed by two cycles of rituximab. PET/CT examinations were performed at baseline, after two cycles (and after four cycles if the patient was PET-positive after two cycles), and at the end of treatment. PET/CT examinations were evaluated locally and by central review. The primary end point was event-free survival at 2 years (2-year EFS). RESULTS: Median age of the 138 evaluable patients was 58.5 years with a WHO performance status of 0, 1, or 2 in 56%, 36%, or 8% of the patients, respectively. By local assessment, 83 PET/CT scans (60%) were reported as positive and 55 (40%) as negative after two cycles of R-CHOP-14. Two-year EFS was significantly shorter for PET-positive compared with PET-negative patients (48% v 74%; P = .004). Overall survival at 2 years was not significantly different, with 88% for PET-positive versus 91% for PET-negative patients (P = .46). By using central review and the Deauville criteria, 2-year EFS was 41% versus 76% (P < .001) for patients who had interim PET/CT scans after two cycles of R-CHOP-14 and 24% versus 72% (P < .001) for patients who had PET/CT scans at the end of treatment. CONCLUSION: Our results confirmed that an interim PET/CT scan has limited prognostic value in patients with diffuse large B-cell lymphoma homogeneously treated with six cycles of R-CHOP-14 in a large prospective trial. At this point, interim PET/CT scanning is not ready for clinical use to guide treatment decisions in individual patients.

Image registration accuracy of an in-house developed patient transport system for PET/CT+MR and SPECT+CT imaging.

OBJECTIVE: The aim of this study was to investigate the registration accuracy of a newly developed patient shuttle system that can integrate different scanners by patient transfer without repositioning for 'hardware'-based image fusion. We aimed to assess the registration accuracy of image fusion in two different settings: a trimodality PET/CT+MR system and a SPECT+CT system. MATERIALS AND METHODS: In this prospective study, 43 patients underwent either sequential PET/CT and MR (n=31) or sequential SPECT and diagnostic CT (D-CT) (n=12). A side-loading patient shuttle system was used for patient transport. For PET/CT+MR, hardware-only coregistration was performed and then validated with anatomical landmarks on CT and MR. SPECT+D-CT image fusion was performed with external cobalt-57 markers and manual fusion. Registration accuracy was analysed by anatomical landmarks on the attenuation correction CT and the D-CT. RESULTS: For the PET/CT+MR system, the mean offset between original CT and MR images in all 31 patients was 8.1±5.7 mm in the X-axis, 5±4 mm in the Y-axis and 4.9±5.6 mm in the Z-axis. The validation of the cobalt-57 marker-assisted SPECT+D-CT fusion yielded offsets of 0.7±1.7 mm in the X-axis, 2.1±1.7 mm in the Y-axis and 0.8±1.8 mm in the Z-axis. CONCLUSION: Sequential PET/CT+MR and SPECT+D-CT imaging using a dedicated patient shuttle system is feasible, resulting in mean offsets between data sets of 10.7 mm using the gantry laser system and 2.4 mm with fiducial markers.

Correlation between therapy response assessment using FDG PET/CT and histopathologic tumor regression grade in hepatic metastasis of colorectal carcinoma after neoadjuvant therapy.

PURPOSE: To evaluate the correlation between change in FDG uptake before and after chemotherapy in hepatic metastases of colorectal carcinoma (HCRC) and a histopathologic tumor regression grade (TRG). METHODS: In patients with HCRC, PET/CT data prior to hepatic surgery were retrospectively analyzed under an IRB waiver. The maximum standard uptake value (SUVmax) was measured before and after chemotherapy. The relative change of FDG activity in the identified lesions was calculated (dSUV). Histopathological specimens of resected metastases were graded on a 5-score TRG scale. A TRG of 1-3 was rated as a responding to therapy, whereas TRG 4-5 were regarded as non-responding lesions. RESULTS: 31 lesions were identified in 23 patients. Mean SUVmax before and after therapy was 6.9 ± 3.7 and 3.5 ± 1.8, respectively. The area under the receiver operator characteristic curve revealed a conclusive correlation between TRG and dSUV (AUC 0.773; 95% confidence interval 0.599-0.946) with a cut off at 41% decrease in FDG activity yielding a sensitivity and specificity of 72 and 75%, respectively. CONCLUSION: A relative change in FDG activity (dSUV) of more than 41% decrease correlated significantly with histopathological tumor regression and might be a prognostic tool for response to chemotherapy in HCRC.

PET/MR imaging of bone lesions--implications for PET quantification from imperfect attenuation correction.

PURPOSE: Accurate attenuation correction (AC) is essential for quantitative analysis of PET tracer distribution. In MR, the lack of cortical bone signal makes bone segmentation difficult and may require implementation of special sequences. The purpose of this study was to evaluate the need for accurate bone segmentation in MR-based AC for whole-body PET/MR imaging. METHODS: In 22 patients undergoing sequential PET/CT and 3-T MR imaging, modified CT AC maps were produced by replacing pixels with values of >100 HU, representing mostly bone structures, by pixels with a constant value of 36 HU corresponding to soft tissue, thereby simulating current MR-derived AC maps. A total of 141 FDG-positive osseous lesions and 50 soft-tissue lesions adjacent to bones were evaluated. The mean standardized uptake value (SUVmean) was measured in each lesion in PET images reconstructed once using the standard AC maps and once using the modified AC maps. Subsequently, the errors in lesion tracer uptake for the modified PET images were calculated using the standard PET image as a reference. RESULTS: Substitution of bone by soft tissue values in AC maps resulted in an underestimation of tracer uptake in osseous and soft tissue lesions adjacent to bones of 11.2 ± 5.4% (range 1.5-30.8%) and 3.2 ± 1.7% (range 0.2-4%), respectively. Analysis of the spine and pelvic osseous lesions revealed a substantial dependence of the error on lesion composition. For predominantly sclerotic spine lesions, the mean underestimation was 15.9 ± 3.4% (range 9.9-23.5%) and for osteolytic spine lesions, 7.2 ± 1.7% (range 4.9-9.3%), respectively. CONCLUSION: CT data simulating treating bone as soft tissue as is currently done in MR maps for PET AC leads to a substantial underestimation of tracer uptake in bone lesions and depends on lesion composition, the largest error being seen in sclerotic lesions. Therefore, depiction of cortical bone and other calcified areas in MR AC maps is necessary for accurate quantification of tracer uptake values in PET/MR imaging.