Objective
Primary brain lymphoma is an aggressive extranodal non-Hodgkin lymphoma with poor prognosis. Many possible prognostic factors are investigated with controversial results, but possible ...prognostic role of 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features remains unclear. Our aim was to study the metabolic behavior of brain lymphoma at 18F-FDG PET/CT and the prognostic impact of qualitative and semiquantitative PET/CT parameters.
Methods
Between 2006 and 2018, 52 patients (26 females and 26 males; mean age: 61 years) with histologically confirmed diagnosis of brain lymphoma who underwent 18F-FDG PET/CT for staging before any treatment were included. PET images were qualitatively and semiquantitatively analyzed by measuring the maximum standardized uptake value body weight (SUVbw), lean body mass (SUVlbm), body surface area (SUVbsa), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The Kaplan–Meier method was used to estimate the progression-free survival (PFS) and overall survival (OS) times. Cox regression models were performed to determinate the relation between qualitative and semiquantitative PET/CT features and OS and PFS.
Results
Thirty-nine patients had positive 18F-FDG PET/CT showing 18F-FDG uptake (mean SUVbw of 18.2; SUVlbm of 13.9; SUVbsa of 5; MTV of 14.8; TLG of 153) at the corresponding cerebral lesion; the remaining 13 were not 18F-FDG avid. Relapse or progression of disease occurred in 22 patients with an average time of 9.7 months; death occurred in 18 patients with an average of 7.9 months. There was no difference in PFS and OS between baseline PET/CT positive and negative groups or considering SUVbw, SUVlbm, and SUVbsa. PFS and OS was significantly shorter in patients with MTV ≥ 9.8 cm
3
(
p
= 0.037 and
p
= 0.022, respectively) and TLG ≥ 94 (
p
= 0.045 and
p
= 0.0430, respectively).
Conclusions
18F-FDG avidity was noted in 75% of cases. Only metabolic tumor parameters (MTV and TLG) were independently correlated with PFS and OS.
PET/CT is the standard for quantitative assessments of myocardial blood flow (MBF), but it requires short-lived-tracers, costly, and not widely available. SPECT with Cadmium Zinc Telluride (CZT) ...detectors allows dynamic acquisition and quantitation of MBF. The study aims were to compare MBF measurements by 99mTc-tetrofosmin-CZT to N13NH3 PET/CT after regadenoson-induced coronary hyperemia and to evaluate the effect of attenuation correction (AC).
54 patients were evaluated at rest and during vasodilation by 99mTc-tetrofosmin-CZT and N13NH3 PET/CT within 2 weeks. MBF and MBF reserve (MFR) were measured by CZT with or without AC (NAC).
The global rest MBF was 0.76 ± 0.19 mL/min/gr by PET and 0.76 ± 0.24 by AC-CZT (P = NS) and 1.14 ± 0.4 by NAC-CZT (P < 0.001 vs PET and AC-CZT). Stress MBF was higher when measured by PET than AC-CZT (1.87 ± 0.45 vs 1.62 ± 0.68 mL/min/gr, P < 0.0008), but lower than NAC-CZT (2.36 ± 1.1, P < 0.0003). The MBF reserve ratio (MFR) was higher by PET than AC-CZT (2.52 ± 0.56 vs 2.22 ± 1 (P < 0.009) and NAC-CZT (2.18 ± 1.0, P < 0.004). Linear regression was better between PET (MFR and stress MBF) and AC-CZT than between PET and NAC-CZT. ROC curve analysis showed the significant ability of AC-CZT to predict MFR < 2 and stress MBF < 1.7 (AUC = 0.75 and 0.82 respectively) and to differentiate between normal and CAD patients (AUC = 0.747 and 0.892 for MFR and stress MBF, respectively).
Our data show a reasonable correlation between MBF and MFR measured by N13NH3-PET and 99mTc-Tetrofosmin-CZT SPECT. NAC-CZT overestimates MBF. AC is recommended when using CZT for measuring MBF.
In patients with multi-vessel disease presenting with ST elevation myocardial infarction (STEMI), the efficacy and safety of ischemia-guided, vs routine non-culprit vessel angioplasty has not been ...adequately studied.
We conducted an international, randomized, non-inferiority trial comparing ischemia-guided non-culprit vessel angioplasty to routine non-culprit vessel angioplasty, following primary PCI for STEMI. The primary outcome was the between-group difference in percent ischemic myocardium at follow-up stress MPI. All MPI images were processed and analyzed at a central core lab, blinded to treatment allocation.
In all, 109 patients were enrolled from nine countries. In the ischemia-guided arm, 25/48 (47%) patients underwent non-culprit vessel PCI following stress MPI. In the routine non-culprit PCI arm, 43/56 (77%) patients underwent angioplasty (86% within 6 weeks of randomization). The median percentage of ischemic myocardium on follow-up imaging (mean 16.5 months) was low, and identical (2.9%) in both arms (difference 0.13%, 95%CI − 1.3%–1.6%, P < .0001; non-inferiority margin 5%).
A strategy of ischemia-guided non-culprit PCI resulted in low ischemia burden, and was non-inferior to a strategy of routine non-culprit vessel PCI in reducing ischemia burden. Selective non-culprit PCI following STEMI offers the potential for cost-savings, and may be particularly relevant to low-resource settings.
(CTRI/2018/08/015384).
The aim of this retrospective study was to investigate the ability of 18 fluorine-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) metrics and radiomics features (RFs) in ...predicting the final diagnosis of solitary pulmonary nodules (SPN). We retrospectively recruited 202 patients who underwent a 18F-FDG-PET/CT before any treatment in two PET scanners. After volumetric segmentation of each lung nodule, 8 PET metrics and 42 RFs were extracted. All the features were tested for significant differences between the two PET scanners. The performances of all features in predicting the nature of SPN were analyzed by testing three classes of final logistic regression predictive models: two were built/trained through exploiting the separate data from the two scanners, and the other joined the data together. One hundred and twenty-seven patients had a final diagnosis of malignancy, while 64 were of a benign nature. Comparing the two PET scanners, we found that all metabolic features and most of RFs were significantly different, despite the cross correlation being quite similar. For scanner 1, a combination between grey level co-occurrence matrix (GLCM), histogram, and grey-level zone length matrix (GLZLM) related features presented the best performances to predict the diagnosis; for scanner 2, it was GLCM and histogram-related features and metabolic tumour volume (MTV); and for scanner 1 + 2, it was histogram features, standardized uptake value (SUV) metrics, and MTV. RFs had a significant role in predicting the diagnosis of SPN, but their accuracies were directly related to the scanner.
The clinical and prognostic role of 2-deoxy-2-18Ffluoro-D-glucose positron emission tomography/computed tomography (2-18FFDG PET/CT) in the study of patients affected by differentiated thyroid ...carcinoma (DTC) with positive serum thyroglobulin (Tg) level and negative 131I whole-body scan (131IWBS) has already been demonstrated. However, the potential prognostic role of semi-quantitative PET metabolic volume features, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), has not yet been clearly investigated. The aim of this retrospective study was to investigate whether the main metabolic PET/CT parameters may predict the prognosis. We retrospectively included 122 patients with a positive 2-18FFDG PET/CT for DTC disease after a negative 131IWBS with Tg > 10 ng/mL. The maximum and mean standardized uptake value (SUVmax and SUVmean), MTV and TLG of the hypermetabolic lesion, total MTV (tMTV) and total TLG (tTLG) were measured for each scan. Progression-free survival (PFS) and overall survival (OS) curves were plotted according to the Kaplan–Meier analysis. After a median follow up of 53 months, relapse/progression of disease occurred in 87 patients and death in 42. The median PFS and OS were 19 months (range 1–132 months) and 46 months (range 1–145 months). tMTV and tTLG were the only independent prognostic factors for OS. No variables were significantly correlated with PFS. The best thresholds derived in our sample were 6.6 cm3 for MTV and 119.4 for TLG. In patients with negative WBS and Tg > 10 ng/mL, 2-18FFDG PET/CT metabolic volume parameters (tMTV and tTLG) may help to predict OS.
Both the myocardial perfusion pattern and myocardial blood flow (MBF) are used to assess patients with suspected coronary artery disease (CAD). The aim of this study was to compare the perfusion ...pattern (using the summed difference score SDS) to MBF in a consecutive group of patients undergoing PET/CT with 13 N-ammonia (13NH3).
47 consecutive patients, aged 65 ± 12 years (42 men) with known or suspected CAD, underwent vasodilator stress/rest PET/CT with 13NH3 for clinical indications. The SDS was determined by a commercially available software based on a 17-segment model. MBF was measured at rest and during hyperemia by dynamic acquisition and single-compartment model analysis. From the rest and stress MBF, the absolute difference (stress-rest) in myocardial blood flow defined as difference in myocardial blood flow (DMBF) was derived.
There were no significant differences between patients with no ischemia (SDS ≤ 1) and those with ischemia (SDS > 1) in CFR (2.84 ± 0.73 vs 2.63 ± 0.89, P = NS) and DMBF (1.34 ± 0.45 vs 1.24 ± 0.53 mL·minute−1·g−1, P = NS). There were however significant regional differences (141 different vascular territories in 47 patients) between these two groups (CFR: 2.84 ± 0.95 vs 2.16 ± 0.57, P < .001 and DMBF: 1.39 ± 0.6 vs 0.87 ± 0.39, P < .0001). The correlation between regional CFR and regional DMBF with SDS was significant (y = 2.7145e−0.059xR = 0.358 and y = 1.2769e−0.119xR = 0.44)
The SDS is the difference between two measurements (stress-rest) and it correlates better with regional DMBF, which is another measurement that reflects the difference between stress and rest. The correlation is better on regional than global basis.
Chronic lymphocytic leukemia (CLL) is an indolent, low-grade B-cell lymphoproliferative disorder, which may evolve into aggressive lymphoma, a phenomenon called Richter syndrome (RS). Our aim was to ...study the accuracy of 2-deoxy-2-18Ffluoro-D-glucose positron emission tomography/computed tomography (2-18F-FDG PET/CT) and its semiquantitative parameters for the detection of RS and the impact on overall survival (OS).
Eighty patients with histologically proven CLL were retrospectively included. PET/CT images were qualitatively and semiquantitatively examined by estimating the maximum standardized uptake value body weight (SUVbw), lean body mass (SUVlbm), body surface area (SUVbsa), lesion-to-blood-pool SUV ratio (L-BP SUV R), lesion-to-liver SUV ratio (L-L SUV R), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) and comparing them with the main clinical-histologic variables. OS curves were plotted according to the Kaplan-Meier method.
Seventy-eight patients had positive 2-18F-FDG PET/CT, whereas the remaining 2 were not FDG-avid. All PET/CT metabolic parameters were significantly higher in the RS group compared with the no-RS group, except for MTV and TLG. The best thresholds identified were 9 for SUVbw, 5.3 for SUVlbm, 1.7 for SUVbsa, 2 for L-L SUV R, and 4.8 for L-BP SUV R. After a median follow-up of 32 months, 24 patients died; OS was significantly shorter in patients with RS than patients without RS (16.5 vs. 27.8 months; P = .001). Binet-stage, B symptoms, SUVbw, SUVlbm, SUVbsa, L-L SUV R, and L-BP SUV R were shown to be independent prognostic features.
Semiquantitative PET/CT parameters that are SUV-related may be useful in discriminating patients with a high risk of developing RS and also for predicting OS.
The present study investigated the potential value of 2-deoxy-2-18Ffluoro-D-glucose positron emission tomography/computed tomography (PET/CT) and its metabolic features for the detection of Richter syndrome (RS) and the impact on overall survival. All PET/CT metabolic parameters were significantly higher in RS compared with the no-RS group, except for metabolic tumor volume and total lesion glycolysis. Overall survival was significantly shorter in patients with RS than in patients without RS. Semiquantitative PET/CT parameters were independent prognostic factors.
Purpose
Distant metastases (DM) from DTC occur in 5–25% of cases and are correlated to lower survival; the prognostic significance of the temporal onset of DM is unclear. Our aim was to ...retrospectively analyze the prevalence of DM and to assess the prognostic role of the timing of manifestation of DM regarding the outcome.
Materials and methods
We included 174 patients (mean age 64 years). According to the time of manifestation, DM were divided in two groups: synchronous DM (SDM,
n
= 108) defined as metastases present at initial diagnosis and metachronous DM (MDM,
n
= 66) as diagnosed during follow-up. SDM were further sub grouped in pre-RAIT when diagnosed during pre-surgery work-up (
n
= 35) and baseline-RAIT when detected by first whole body scan after RAIT (
n
= 73). Disease-specific survival (DSS) was analyzed using the Kaplan–Meier method.
Results
Total RAI activities and number of treatments were significantly higher in MDM, also loss of RAI avidity was more frequent in MDM. Forty-four patients died during follow-up, of which 41 were DTC-related deaths, 5-year and 10-year DSS were 80% and 56%. On univariate analysis MDM had significantly shorter DSS; also histotype and RAI avidity were significant risk factors of impaired survival. On multivariate analysis, only loss of RAI avidity remained as independent negative predictor (
p
= 0.043). Considering SDM, DSS was significantly shorter in pre-RAIT group than baseline-RAIT (
p
= 0.004). Instead there was no significant difference between pre-RAIT-SDM and MDM in survival outcome (
p
= 0.875).
Conclusions
In DTC with DM, loss of RAI uptake has an important role in survival. No significant difference in survival outcome was discovered between SDM and MDM; but, among SDM, pre-RAIT had significant shorter DSS than baseline-RAIT.
We proposed a method of synthesis to produce 11CCholine using TRACERlab FXc module that utilized gas phase iodination. The product had radiochemical purity of 99.79 ± 0.14 % and specific activity of ...45.7 ± 7.59 GBq/μmol. 11CCholine did not have at the moment a specific monograph in European Pharmacopeia therefore we used, when possible, as quality controls reference the monograph of 18FFDG and we proposed suitable methods to verify radiochemical purity and to quantify residual DMAE and choline amounts.
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