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Purpose: This study investigates the prognostic value of 68Ga-Pentixafor PET/CT using PET-derived quantitative in multiple myeloma (MM) patients with suspected recurrence in comparison to 18F-FDG PET/CT and clinical data. Methods: Twenty-four MM patients with suspicion for relapse who underwent 68Ga-Pentixafor and 18F-FDG PET/CT were retrospectively evaluated. Total bone marrow glycolysis for 18F-FDG (TBMFDG) and total bone marrow uptake for 68Ga-Pentixafor PET/CT (TBMCXCR4) were calculated using whole-body metabolic tumor burden obtained by dedicated software (MIM 7.0.6). The patients were followed for 19–24 months, and the association of PET-derived quantitative data with overall survival (OS) was analyzed. Results: 68Ga-Pentixafor PET/CT was positive in 17 patients, of which 13 were also positive on 18F-FDG PET/CT, whereas 7 patients were negative on both scans. The positive rate of 68Ga-Pentixafor and 18F-FDG PET/CT on a patient-based approach was 70.8% and 54.1%, respectively. 68Ga-Pentixafor positivity was significantly associated with OS (p = 0.009), and 18F-FDG positivity was at the margin of statistical significance (p = 0.056). TBMCXCR4 and TBMFDG were negatively correlated with OS (r = −0.457, p = 0.025 and r = −0.617, p = 0.001, respectively). The OS was negatively correlated with beta-2-microglobulin levels (r = −0.511, p = 0.01) and CRAB score (r = −0.592, p = 0.002) as an indicator of the end-organ disease, which confirmed these results. Serum beta-2-microglobulin levels and CRAB score were also correlated with TBMCXCR4 (r = 0.442, p = 0.039 and r = 0.573, p = 0.003, respectively) and TBMFDG (r = 0.543, p = 0.009 and r = -0.424, p = 0.003, respectively). Conclusion: 68Ga-Pentixafor PET/CT positivity is a negative prognostic factor in the survival outcome of MM patients. Complementary 68Ga-Pentixafor PET/CT has the potential to overcome 18F-FDG PET/CT limitations and helps a more precise risk stratification. [ABSTRACT FROM AUTHOR]

Objective: Minimizing side effects by using response-adopted therapy strategies plays an important role in the management of pediatric Hodgkin lymphoma (HL); however, the criteria for the definition of adequate or inadequate response are controversial. The aim of this study is to compare different methods of interpretation of 18F-FDG-PET/CT (PET) in the prediction of disease outcome in order to determine the optimum method in this regard.Methods: Baseline, interim and post-treatment PET scans of 72 children were interpreted according to revised International Harmonization Project criteria (IHP) and Deauville criteria. Cut-off values for changes in interim and post-treatment FDG uptake (ΔSUVmax) in the prediction of progression-free survival (PFS) were measured using ROC analysis. Quantitative and visual data were compared with each other in the prediction of PFS.Results: Mean interim and post-treatment ΔSUVmax of the primary lesions were 77.4 ± 19.5 and 68.8 ± 30.4% and respective cut-off values were 82 and 73%. However, only post-treatment ΔSUVmax yielded statistically significant results in the prediction of 3-year PFS (p = 0.043). Interim ΔSUVmax was further analyzed according to the values reported in the literature (66 and 77%) yet statistically significant results were not reached (p = 0.604 and 0.431). For interim evaluation, IHP criteria was correlated to Deauville criteria (p = 0.002 and p = 0.001) and ΔSUVmax (p = 0.03), whereas for post-treatment evaluation, significant correlation with ΔSUVmax (p = 0.04) but marginally significant (p = 0.055 and p = 0.058) correlation with Deauville criteria were achieved. Overall, 1, 3 and 5-year PFS were 95.7 ± 0.2, 89.6 ± 0.4 and 80.8 ± 0.7%, respectively. All methods demonstrated comparable performance in the prediction of 3-year PFS; however, interim PET using Deauville criteria and post-treatment PET using IHP criteria were statistically significant. All methods demonstrated high negative-predictive value but substantially low positive-predictive value.Conclusions: Deauville criteria are superior to other methods in the prediction of pediatric HL outcome using interim PET data. On the other hand, quantitative evaluation and visual evaluation by IHP can be used reliably at the end of the treatment. In this regard, we report the optimal cut-off value of SUVmax reduction as 73%. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to determine the range of SUV of 68Ga-DOTATATE in normal organs and tumoral lesions and establish uptake unrelated to NET. Materials and methods: One hundred and twenty patients (57 men, 63 women), who underwent Ga-DOTATATE PET/CT imaging in our institution were analyzed. Patients were indicated for Ga-DOTATATE PET/CT imaging to detect primary tumor or metastasis of suspected or previously known NET, to determine SSTR positivity and to detect occult source of ectopic Cushing syndrome. Normal range of uptake was calculated for the organs that were proven to have no pathology by either conventional radiological imaging or clinical follow-up, using SUV as a semiquantitative measure. Uptake and tumor to background ( T/ B) ratios of tumoral lesions in liver, pancreas, bone, brain and lymph nodes were calculated. Uptakes due to lesions unrelated to NET were also documented. Results: Significant uptake was found in spleen, kidneys, adrenal glands, liver and pituitary gland with mean SUV of 24.67, 14.30, 13.73, 9.12 and 9.74 respectively. Uptake was measured separately for the pancreatic head and body separately, however, besides a slightly heterogeneous uptake; the difference was not statistically significant. Uptake in the tumoral lesions had high ( T/ B) ratios with mean SUV of 28.72, 25.21, 18.28, 34.73 and 12.59 for liver, pancreas, bone, brain and lymph nodes, respectively. Incidental benign tumoral lesions were detected in 3 patients (2.5 %) which were meningioma and fibrous dysplasia demonstrating significant and breast fibroadenoma demonstrating mild Ga-DOTATATE uptake. Non-neoplastic processes were detected in 4 patients (14.1 %), including postsurgical inflammation, reactive lymph nodes, arthritis and demonstrated faint to mild Ga-DOTATATE uptake, with the exception of significant uptake in accessory spleen. Conclusion: Ga-DOTATATE has high T/ B ratio with physiological biodistribution comparable to its counterparts. However, the presence of SSTRs in benign and malignant lesions unrelated to NET may be challenging in interpretation particularly where the physiological uptake is variable. [ABSTRACT FROM AUTHOR]

Purpose: Pulmonary carcinoid (PC) tumors are rare neoplasms of the lung with good prognosis but diagnosis may be demanding since there is no exclusive modality alone to clearly differentiate a PC tumor. The purpose of this study is to establish the diagnostic features of somatostatin receptor scintigraphy (SRS), comparatively (where available) with FDG PET/CT (PET/CT) correlated with histopathologic findings. Methods: Twenty-one patients who underwent SRS with In-octreotide and were diagnosed as having PC tumors were retrospectively studied. Thirteen patients were performed PET/CT. Primary tumour size, Ki-67 indexes, image analysis data of SRS and PET/CT including maximum standardized uptake values (SUVmax) together with false negative, false positive, true positive and true negative lesions were documented and discussed. Results: Eleven (52.4 %) patients were typical (TC) and 10 (47.6 %) were atypical carcinoids (AC) with mean Ki-67 indexes of 2.1 and 24 %, respectively. Patients underwent SRS for solitary pulmonary nodule (SPN) characterization ( n = 12) and determination of disease extension ( n = 9). Overall sensitivity and specificity of SRS in the detection of primary tumour, lymph nodes (LN) and distant metastasis (DM) were 76 and 97 %, respectively, whereas, positive and negative predictive values were 95 and 86 %. PET/CT was performed for determining disease spread ( n = 3) and metabolic characterization ( n = 10) of SPNs. Mean SUVmax in the primary pulmonary lesion in TCs and ACs were 2.9 ± 0.8 and 7.9 ± 5.4, respectively. Nodal involvement ( n = 5) and DM ( n = 3) were also detected. Sensitivity and specificity of PET/CT in the detection of primary tumour, LNs and DM were 85 and 89.4 %, respectively. Conclusion: SRS is useful in the diagnosis and monitoring of PC tumors when incorporated with FDG PET/CT as a primary staging tool particularly in the determination of disease spread. [ABSTRACT FROM AUTHOR]