Pretherapy TMTV is an independent predictor of outcome in patients with DLBCL.
Measurement of baseline TMTV in lymphoma using a fixed 41% SUVmax threshold is reproducible and correlates with the other parameters for tumour mass evaluation. It should be evaluated in prospective studies.
Cardiac amyloidosis (CA) is recognized as a common cause of restrictive cardiomyopathy and heart failure due to the deposition of insoluble proteins in the myocardial interstitium. We emphasize the role of [18F]-sodium fluoride (NaF) PET/CT as a potential noninvasive tool to identify and differentiate the transthyretin-related cardiac amyloidosis from the light-chain cardiac amyloidosis. We report cases of a 73-year-old man and a 75-year-old woman followed in our center for congestive heart failure with marked alteration of the left ventricular ejection fraction due to familial transthyretin Val122Ile cardiac amyloidosis and light-chain cardiac amyloidosis, respectively, confirmed on endomyocardial biopsy.
This study evaluated the clinical impact of contrast-enhanced computed tomography (CECT) on routine management of patients with lymphoma. Over a 1-year period, 237 CECT scans were performed prospectively in 163 patients after low-dose (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT). Scans were performed at staging (n = 41), interim (n = 73), post-therapy (n = 115) and follow-up (n = 8). Clinical impact was determined from the multidisciplinary committee reports. CECT had no clinical impact in 219 cases (92%). A clear impact was noted in only 3%, i.e. up-staging of lymphoma (n = 2) and diagnosis of deep vein thrombosis (n = 5). A debatable impact was noted in the remaining 11 cases, consisting of additional investigations, either without therapeutic impact (n = 8), or resulting in delay of therapy onset (n = 2) or ablative surgery (n = 1). CECT delivered an average 33.5 ± 3.8 mSv vs. 17.7 ± 2.8 mSv for PET/CT. In conclusion, the clinical impact of CECT seems limited, although scarce, life-threatening conditions were diagnosed. Imaging of lymphoma needs optimization to reduce radiation exposure.
The acute chest syndrome (ACS) is the main cause of mortality among adult patients with sickle cell disease (SCD). Its pathophysiology is still unclear. Using positron emission tomography (PET) with 18F-fluorodeoxyglucose [18F-fluorodeoxyglucose (18F-FDG)], we explored the relationship between regional lung density and lung metabolism, as a reflection of lung neutrophilic infiltration during ACS.Patients were prospectively enrolled in a single-center study. Dual modality chest PET/computed tomography (CT) scans were performed, with 18F-FDG emission scans for quantification of regional 18F-FDG uptake and CT scans with radiocontrast agent to check for pulmonary artery thrombosis. Regional lung 18F-FDG uptake was quantified in ACS patients and in SCD patients without ACS (SCD non-ACS controls). Maximal (SUVmax) and mean (SUVmean) standardized uptake values were computed.Seventeen patients with ACS (mean age 28.3 ± 6.4 years) were included. None died nor required invasive mechanical ventilation. The main lung opacity on CT scans was lower lobe consolidation. Lungs of patients with ACS exhibited higher SUVmax than those of SCD non-ACS controls (2.5 [2.1–2.9] vs 0.8 [0.6–1.0]; P < 0.0001). Regional SUVmax and SUVmean was higher in lower than in upper lobes of ACS patients (P < 0.001) with a significant correlation between lung density and SUVmax (R2 = 0.78). SUVmean was higher in upper lobes of ACS patients than in lungs of SCD non-ACS controls (P < 0.001). Patients with SUVmax >2.5 had longer intensive care unit (ICU) stay than others (7 [6–11] vs 4 [3–6] days; P = 0.016).Lungs of patients with ACS exhibited higher 18F-FDG uptake than SCD non-ACS controls. Lung apices had normal aeration and lower 18F-FDG uptake than lung bases, but higher 18F-FDG uptake than lungs of SCD non-ACS controls. Patients with higher lung 18F-FDG uptake had longer ICU stay than others.
1598 Tumor bulk assessed by maximum tumor diameter was previously found to influence the outcome of young patients with low risk (aaIPI 0–1) DLBCL (Pfreundschuh et al Lancet Oncol, 2011; 12: 1013), but the prognostic impact of bulk and more generally tumor volume in high-risk DLBCL remains to be explored. Conversely, maximum SUV reduction calculated between baseline PET and PET performed after 4 cycles of immunochemotherapy (ΔSUVmax0–4) was recently shown to predict outcome in this population (Casasnovas et al Blood 2011; 118: 37). In this study, we assessed the metabolic tumor volume (MTV) and the tumor bulk at baseline in 121 patients <60 years with an aaIPI2–3 DLBCL enrolled in the LNH07-3B trial (NCT00498043). We then compared the prognosis value of both parameters to that of ΔSUVmax0–4. MTV was measured by FDG PET/CT with a semi automatic method using various volume shapes and systematic 41% SUVmax thresholding. Tumor mass with a maximum diameter > 10 cm assessed on CT scan was considered as bulky. Median follow-up was 28 months. Median baseline MTV was 303 cc (17–1488). Baseline MTV (≥625 cc vs <625cc, on the basis of a ROC analysis) significantly predicts 2-year progression free survival (2y-PFS) (57 % vs 83%; p=0.0032) and 2-year overall survival (2y-OS) (60% vs 90%; p=0.002). By contrast bulk >10 cm was not predictive of outcome. As previously published ΔSUVmax0–4 (> 70% vs ≤70%) found to predict 2y-PFS (88% vs 40%; p<10-4) and 2y-OS (94% vs 59%; p<10-4). Combining baseline MTV to early response assessed by ΔSUVmax0–4 allows to split the group of good responders patients defined on the basis of ΔSUVmax0–4 >70% after 4 cycles of immunochemotherapy (n=101, 88%) into 2 separated prognosis subsets (2y-PFS: 90% vs. 77%, p<10-4; 2y-OS: 96% vs. 77%, p<10-4). So far MTV could not significantly identify subgroups within the 15 patients with ΔSUVmax≤70% even if patients with higher MTV base line had lower PFS and OS. In our series baseline MTV was predictive of PFS and OS in high risk DLBCL patients while bulk was not. MTV identified different risk categories of DLBCL patients within DLBCL patients with a good interim response (ΔSUVmax0–4 >70%) and may improve the negative predictive value of interim PET. Disclosures: No relevant conflicts of interest to declare.
and 4 Radiopharmacy, Hôpital Tenon, AP-HP, Paris 123 I-metaiodobenzylguanidine (MIBG) and 111 In-pentetrotide SPECT have been used for functional imaging of neuroendocrine tumors (NETs) for the last 2 decades. More recently, PET/CT imaging with 18 F-FDG, 18 F-fluorodihydroxyphenylalanine (FDOPA), and 68 Ga somatostatin-receptor ligands in NETs has been expanding. A literature search could find no direct measurements of the dose rate from NET patients exiting the nuclear medicine department after undergoing PET/CT with 18 F-FDOPA or 68 Ga-DOTATOC, a somatostatin analog. Methods: We measured the dose rates from 93 NET patients on leaving the department after undergoing PET/CT or SPECT/CT in our centers. In total, 103 paired measurements of equivalent dose rate at 1 m (EDR-1m) from the sternum and urinary bladder were obtained. The detector faced the sternum or bladder and was 1 m away from and directly in front of the patient. The practice for exiting the department differed according to whether the patient had been referred for PET/CT or for SPECT/CT. PET/CT patients were discharged after imaging, whereas SPECT/CT patients left the department earlier, just after radiopharmaceutical injection. Results: The median administered activity was 122 MBq in 53 68 Ga-DOTATOC PET/CT studies, 198 MBq in 15 18 F-FDOPA PET/CT studies, and 176 MBq in 13 18 F-FDG PET/CT studies. The corresponding median EDR-1m was 4.8, 9.5, and 8.8 mSv/h, respectively, facing the sternum, and 5.1, 10.1, and 9.5 mSv/h, respectively, facing the bladder. The median administered activity was 170 MBq in 12 111 In-pentetreotide SPECT/CT studies and 186 MBq in 10 123 I-MIBG SPECT/CT studies. The corresponding median EDR-1m was 9.4, and 4.9 mSv/h, respectively, at the level of the sternum, and 9.3 and 4.7 mSv/h, respectively, at the level of the bladder. The EDR-1m was less than 20 mSv/h in all patients. Thus, when exiting the nuclear medicine department, the NET patients injected with 68 Ga-DOTATOC or 123 I MIBG emitted an average EDR-1m roughly half that of patients injected with other radiopharmaceuticals. This finding is a complementary argument for replacing SPECT by PET somatostatin-receptor imaging. Conclusion: Our current practice of allowing patients to exit after PET/CT imaging or just after SPECT radiopharmaceutical injection appears to be safe from a radiation protection point of view. Restrictive advice is unnecessary for NET patients being discharged from the department.
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