Positron Emission Tomography Score Research Articles

Pre-treatment 18f-FDG PET/CT for Assessing and Predicting Bone Marrow Involvement in Patients with Newly Diagnosed Peripheral T-Cell Lymphoma

Objective: To explore the value of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in assessing and predicting bone marrow involvement (BMI) in patients with newly diagnosed peripheral T-cell lymphoma (PTCL) prior to treatment. Methods: This retrospective study included 201 eligible patients of PTCL who received bone marrow biopsy (BMB) and PET/CT between January 2017 and December 2022. Extra subgroup analysis was designed considering the variation of avidity of FDG in different distinct entities. The status of bone marrow (BM) by PET was assessed using a visual examination and a quantitative index (the highest SUV of BM divided by the mean SUV of the liver [M/L]). Prognostic value of BM findings was also evaluated regarding progression free survival (PFS) and overall survival (OS). Results: The sensitivity and specificity of PET/CT for patients with confirmed PTCL by BMB were 43.2% and 90.2%, respectively. As for subgroup analysis, the kappa value reflecting the agreement between BMB and visual analysis in angioimmunoblastic T-cell lymphoma (AITL), peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma (ALCL) as well as nodal T-follicular helper (TFH) cell lymphoma (PTCL-TFH) was 0.315, 0.307, 0.426 and 0.581, respectively. (Give the number of cases in each lymphoma group) PET score was an independent factor for PFS (P =0.011) but not for OS (P =0.840). In addition, 25 patients with stage I to II disease had no evidence of BMI by either PET/CT or BMB. Image-guided biopsy was also recommended when PET/CT showed a focal FDG uptake outside the iliac crest. Quantitative analysis revealed the differences in the two-level of M/L; however, they were not statistically significant for both PFS and OS (P =0.246 and P =0.227). Conclusion: PET/CT has a complementary role in assessing BMI and prognosis in PTCL patients.

18F-sodium fluoride positron emission tomography provides pertinent additional information to computed tomography for assessment and management of tarsal pain in horses.

To assess the value of 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) for imaging the tarsus and proximal metatarsus and compare it with CT and lameness evaluation. 25 horses with lameness localized to the tarsal and proximal metatarsal regions that underwent 18F-NaF PET/CT between 2016 and 2021. 18F-NaF PET and CT images were retrospectively independently evaluated by 3 observers. Standardized uptake values (SUV) were used to characterize 18F-NaF uptake. Correlation between PET and CT findings with subjective and objective maximum (Max-D) and minimum pelvic height lameness data was estimated. The inter-observer Kappa-weighted value (κ) was higher for PET (κ = 0.66) than CT (κ = 0.6). CT and PET scores were fairly correlated (R = 0.49; P < 0.05). PET SUVratio (SUV of the main lesion/SUV talus) had the highest correlation with Max-D (R = 0.71; P < .05). PET and CT scores for the plantar region were significantly higher in Quarter Horses (P < .05) and showed consistently higher correlation with objective lameness data (CT plantar grade - Max-D [R = 0.6; P < .05], PET plantar grade - Max-D [R = 0.47; P = .04]) than other regions of the distal tarsal joints. Three Warmbloods presented marked uptake at the medial cochlea of the distal tibia. PET had a moderate correlation with CT for assessment of tarsal lesions. The degree of PET uptake can help differentiate active versus inactive lesions. Specific location of the uptake is important in determining clinical relevance.

Correlations between APOE4 status and regional amyloid and tau burdens in cognitively normal older individuals

AbstractBackgroundThe correlations between apolipoprotein epsilon 4 (APOE4) status and regional Alzheimer’s disease–related biomarkers in cognitively normal elderly are not fully understood. Our cross‐sectional study compared clinical characteristics, amyloid/tau burden, and cortical thickness according to APOE4 carrier status to assess correlations between APOE4 and regional biomarker burdens.MethodWe analyzed 185 cognitively normal participants from the ADNI 3 cohort study. Participants aged 55‐90 with normal cognitive function were eligible. We divided participants into Aß+ APOE4 carriers (group 1, n = 27), Aß+ APOE4 non‐carriers (group 2, n = 29), and Aß‐ normal controls regardless of APOE4 carrier status (group 0, n = 129). We compared clinical characteristics, cerebrospinal fluid (CSF) amyloid β42 &amp; phosphorylated tau, florbetapir positron emission tomography (PET), flortaucipir PET, cortical thickness, and cognitive scores among the 3 groups. Quantitative imaging analyses were performed using the standardized uptake value ratio (SUVR). We additionally assessed correlations between APOE4 carrier status and imaging biomarkers.ResultThe baseline characteristics except age were similar among the groups. The participants in group 2 were oldest. The regional amyloid/tau SUVRs did not differ between groups 1 and 2, but the amyloid/tau SUVRs in most regions were numerically higher in group 1 than group 2 after adjusting for age difference. The regional amyloid and tau SUVRs in the younger (&lt;70) group were higher in group 1 than group 2. APOE4 carrier status showed significant association with amyloid burden in diffuse cortical areas after adjustment for age and sex, but it was not associated with regional tau burden or cortical thickness.ConclusionWe identified that cognitively normal APOE4 carriers showed similar but numerically greater amyloid and tau burdens than did APOE4 non‐carriers after adjusting for age. APOE4 carrier status might be more highly associated with amyloid deposition than with other AD‐related biomarkers such as tau or cortical thickness, especially in the younger group below 70.

Baseline PET radiomics outperforms the IPI risk score for prediction of outcome in diffuse large B-cell lymphoma

AbstractThe objective of this study is to externally validate the clinical positron emission tomography (PET) model developed in the HOVON-84 trial and to compare the model performance of our clinical PET model using the international prognostic index (IPI). In total, 1195 patients with diffuse large B-cell lymphoma (DLBCL) were included in the study. Data of 887 patients from 6 studies were used as external validation data sets. The primary outcomes were 2-year progression-free survival (PFS) and 2-year time to progression (TTP). The metabolic tumor volume (MTV), maximum distance between the largest lesion and another lesion (Dmaxbulk), and peak standardized uptake value (SUVpeak) were extracted. The predictive values of the IPI and clinical PET model (MTV, Dmaxbulk, SUVpeak, performance status, and age) were tested. Model performance was assessed using the area under the curve (AUC), and diagnostic performance, using the positive predictive value (PPV). The IPI yielded an AUC of 0.62. The clinical PET model yielded a significantly higher AUC of 0.71 (P < .001). Patients with high-risk IPI had a 2-year PFS of 61.4% vs 51.9% for those with high-risk clinical PET, with an increase in PPV from 35.5% to 49.1%, respectively. A total of 66.4% of patients with high-risk IPI were free from progression or relapse vs 55.5% of patients with high-risk clinical PET scores, with an increased PPV from 33.7% to 44.6%, respectively. The clinical PET model remained predictive of outcome in 6 independent first-line DLBCL studies, and had higher model performance than the currently used IPI in all studies.

PET Criteria by Cancer Type from Imaging Interpretation to Treatment Response Assessment: Beyond FDG PET Score.

in recent years, the role of positron emission tomography (PET) and PET/computed tomography (PET/CT) has emerged as a reliable diagnostic tool in a wide variety of pathological conditions. This review aims to collect and review PET criteria developed for interpretation and treatment response assessment in cases of non-[18F]fluorodeoxyglucose ([18F]FDG) imaging in oncology. A wide literature search of the PubMed/MEDLINE, Scopus and Google Scholar databases was made to find relevant published articles about non-[18F]FDG PET response criteria. The comprehensive computer literature search revealed 183 articles. On reviewing the titles and abstracts, 149 articles were excluded because the reported data were not within the field of interest. Finally, 34 articles were selected and retrieved in full-text versions. available criteria are a promising tool for the interpretation of non-FDG PET scans, but also to assess the response to therapy and therefore to predict the prognosis. However, oriented clinical trials are needed to clearly evaluate their impact on patient management.

Metabolic positron emission tomography/CT response after induction chemotherapy and chemo(re)irradiation is associated with higher negative resection margin rate in patients with locally recurrent rectal cancer.

Positron emission tomography (PET)/CT can be used to monitor the metabolic changes that occur after intensified treatment with induction chemotherapy and chemo(re)irradiation for locally recurrent rectal cancer (LRRC). This study aimed to analyse the correlation between the PET/CT response and final histopathological outcomes. All LRRC patients who underwent induction chemotherapy prior to surgery between January 2010 and July 2020 and were monitored with pretreatment and post-treatment PET/CT were included. Visual qualitative analysis was performed, and patients were scored as having achieved a complete metabolic response (CMR), partial metabolic response (PMR) or no response (NR). The histopathological response was assessed according to the Mandard tumour regression (TRG) score and categorized as major (TRG 1-2), partial (TRG 3) or poor (TRG 4-5). The PET/CT and TRG categories were compared, and possible confounders were analysed. A total of 106 patients were eligible for analysis; 24 (23%) had a CMR, 54 (51%) had a PMR and 28 (26%) had NR. PET/CT response was a significant predictor of the negative resection margin rate, achieving 96% for CMR, 69% for PMR and 50% for NR. The overall accuracy between PET score and pathological TRG was 45%, and the positive predictive value for CMR was 63%. A longer interval between post-treatment PET/CT and surgery negatively influenced the predictive value. Metabolic PET/CT response evaluation after neoadjuvant treatment proves to be a complementary diagnostic tool to standard MRI in assessing tumour response, and may play a role for treatment planning in LRRC patients.

Pre-Transplantation FDG-PET Predicts Early but Not Late Survival Outcomes Following Allogeneic Transplantation in Chemo-Sensitive Hodgkin Lymphoma

Positron emission tomography (PET) is increasingly employed both to guide response-adjusted therapeutic strategies and to provide prognostic information in patients with Hodgkin Lymphoma (HL). The presence of residual [18-F]FDG-avid lesions prior to autologous stem cell transplantation (ASCT) confers a poor prognosis in terms of relapse risk and event-free survival outcomes, even when analysis is restricted to those with chemo-sensitive disease. The prognostic power of PET in the setting of allogeneic SCT remains more contentious, with relatively little data currently published. Information is particularly sparse in terms of outcomes relating to specific histological subtypes of lymphoma.We identified 160 patients transplanted for HL at four UK transplant centers using T-cell depleted conditioning regimens, based either on fludarabine-melphalan-alemtuzumab (FM-C) or the BCNU-etoposide-cytarabine-melphalan-alemtuzumab (BEAM-C) backbone, in whom pre-transplantation PET data were available. These represent the primary data set. Median age was 30 (12-66) years; 59 had failed a prior ASCT and these patients more commonly received FM-C (56/59 vs 26/101, p<0.001); median number of prior lines of treatment was 4 (2-10); median follow-up was 3.1 years in patients remaining alive. A Deauville score could be assigned according to a visual analysis 5-point scale in 137 cases following central review of digital file data; D1-2 (metabolic complete response) n=54, D3 n=13, D4 n=36, D5 n=34. Of those with a D5 score, 18 were non-progressive, and 16 progressive (D5p) prior to transplant. Overall survival (OS) was significantly worse in the D5p subset (19% [0-41%] at 4 years, p=0.001); it did not differ significantly between D1-2 vs D3-5 (78%[66-90%] vs 67%[54-80%], p=0.626), although the OS curves demonstrated early divergence from years 1-4 followed by convergence at later time points (Figure). The worse OS in the D5p cohort related both to a higher non-relapse-related mortality (NRM)(29%[12-65%] at 1 year) and a higher relapse risk (RR)(38%[19-76%] at 4 years). The latter were equivalent for the D1-2 vs D3-5 cohorts (NRM 17%[9-31%] vs 17% [10-30%] at 1 year; RR 23%[13-40%] vs 24% [15-38%] at 4 years respectively)(Figure). Interestingly the kinetics of relapse differed between the latter 2 groups, with relapse occurring later in the D1-2 cohort, again illustrated by early divergence (RR 16%[9-31%] vs 24%[15-38%] at 2 years) followed by later convergence from year 4. Progression free survival was also equivalent (57%[43-72%] vs 54%[41-67%] at 4 years respectively, p=0.347). Although the number of patients with non-progressive D5 scores was relatively small, exploratory analyses revealed no significant differences in survival outcomes between those with D4 vs D5 scores. Analysis of survival outcomes of D1-3 vs D4-5 also revealed no statistically significant differences.In summary, these data from a large cohort of patients with HL undergoing T-cell depleted allogeneic SCT illustrate inferior outcomes in those with progressive disease prior to transplantation, an altered kinetic of relapse and early survival advantage for those with Deauville 1-2 PET scores compared to those with non-progressive Deauville 3-5 PET scores, but no statistically significant differences in longer term outcomes including relapse risk, PFS and OS. Importantly, these data suggest that the allogeneic graft-versus-tumor activity likely overcomes the poor prognostic impact that has been demonstrated with residual metabolically active disease in the context of conventional dose escalation and ASCT, supporting further exploration of response-adjusted transplantation algorithms. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

SAT0224 Macrophage Targeting by Positron Emission Tomography (PET) Imaging Detects Subclinical Synovitis in Hands and Wrists in Early RA Patients in Clinical Remission

BackgroundIn rheumatoid arthritis (RA), intensive treatment regimens aim to achieve a status of clinical remission (CR). Unfortunately, recurrent flares in RA patients in CR are not an uncommon phenomenon1. Studies...

SAT0531 Association between Presence of Subclinical Synovitis on (R)-11C-PK11195 Positron Emission Tomography and Clinical Outcome in Rheumatoid Arthritis Patients without Clinical Synovitis

BackgroundRemission of disease is the best possible outcome of treatment regimens in rheumatoid arthritis (RA). However, definitions of clinical remission, including the most recent ACR/EULAR definitions are all based on...

On the Added Value of Baseline FDG-PET in Malignant Lymphoma

PurposeThe added value of baseline positron emission tomography (PET) scans in therapy evaluation in malignant lymphoma is unclear. In guidelines, baseline PET is recommended but not mandatory except in lymphoma types with variable fluoro-d-glucose uptake. The aim of the present study was to test the hypothesis that adding baseline PET information decreases false positive readings with posttreatment PET and improves observer agreement.MethodsForty-four patients (mean age 56 years, standard deviation 14) with malignant lymphoma were included. Two nuclear medicine physicians retrospectively and independently evaluated the posttreatment PET, 3 weeks later followed by paired reading of baseline and posttreatment PET. For each PET, 22 regions were classified as positive, negative, or equivocal, resulting in an overall PET score of positive, unclear, or negative. In case of discrepancies, consensus was reached.ResultsAddition of baseline to posttreatment PET evaluation affected the classification of metabolic response in 34% of malignant lymphoma patients treated with first-line chemotherapy. In one out of seven patients, addition of the baseline PET lead to opposite conclusions (95% confidence interval 4–14). False positivity was reduced by adding the baseline scan information, but the effect on false negativity was similar. In addition, the amount of unclear classifications halved after paired reading. Observer agreement did not improve upon adding the baseline PET data.ConclusionWithout any other clinical information, pretreatment PET facilitates changes the interpretation of a posttreatment PET in a third of the patients, resulting in both upgrading and downgrading of the posttreatment situation of a malignant lymphoma patient. If these results are confirmed for PET–computed tomography systems, they favor the addition of baseline PET to the current work-up of patients with malignant lymphoma.

Relationship Between Non-small Cell Lung Cancer FDG Uptake at PET, Tumor Histology, and Ki-67 Proliferation Index

We compared primary non-small cell lung cancer (NSCLC) F-fluorodeoxyglucose (FDG) uptake at positron emission tomography (PET) to tumor histologic features and Ki-67 proliferation index. This large, prospectively-recruited patient cohort has previously been analyzed based on differences in FDG uptake across stage groups; the current analysis adds further dimensions to this characterization. One hundred seventy-eight patients with potentially-resectable NSCLC were scanned with FDG PET before therapy. A partial volume correction algorithm was used to correct FDG uptake values for their dependence on tumor size. Primary tumor resection specimens, core biopsies, and biopsies of metastatic lymph nodes were used to assess each tumor's NSCLC histologic subtype, degree of differentiation, and Ki-67 proliferation index. Bronchioalveolar carcinomas were found to have lower FDG uptake at PET and lower Ki-67 scores than any other histologic subtype. Non-bronchioalveolar adenocarcinomas had lower FDG uptake and Ki-67 scores than squamous cell carcinomas or large cell undifferentiated carcinomas. Better differentiated NSCLCs had lower FDG uptake and Ki-67 scores than more poorly differentiated NSCLCs. There was a significant positive correlation between FDG uptake and Ki-67 scores. Partial volume correction increased the strength of this correlation, while also diminishing the strong positive correlation between FDG uptake and tumor size. There are significant differences in NSCLC FDG uptake across histologic subtypes and differentiation groups. These differences parallel nearly identical differences in Ki-67 scores, implying that differences in NSCLC tumor cell proliferation may give rise to commensurate differences in tumor glucose metabolism.

Grooved pegboard test as a biomarker of nigrostriatal denervation in Parkinson's disease

Recent pharmacotherapy trials in Parkinson's disease (PD) using dopaminergic neuroimaging as outcome parameter failed to show significant relationships between imaging and clinical results. One possible explanation is that there is a non-linear relationship between striatal denervation and motor performance reflecting a statistical "floor" effect in the imaging data with advanced disease. Both the motor manifestations and the striatal dopamine denervation of idiopathic PD, however, are typically asymmetric and more meaningful associations may be found by comparing data from the least denervated striatum with motor performance in the corresponding body side. PD patients (n=28) underwent [11C]beta-CFT dopamine transporter (DAT) positron emission tomography (PET) and grooved pegboard testing. Voxel-based analysis of DAT PET and bimanual pegboard scores demonstrated significant correlation clusters within the bilateral striata (P<0.001). However, findings were most prominent in the least denervated striatum. There was a significant inverse correlation between pegboard scores of the least affected arm and DAT binding of the least denervated striatum (Rs=-0.69, P<0.0001) but no significant correlation between pegboard scores of the clinically most affected arm and DAT binding of the most denervated striatum (Rs=-0.15, ns). These data indicate that the robustness of the grooved pegboard test as a biomarker for nigrostriatal denervation in PD mainly reflects the relationship between test performance of the clinically least affected limb and the least denervated striatum. These findings indicate that there is both a statistical "floor" and "ceiling" effect for the most affected striatal and body sides that must be considered when employing imaging as an outcome measure in clinical trials in PD.

Is chronically dysfunctional yet viable myocardium distal to a severe coronary stenosis hypoperfused?

Background. Controversy exists regarding the perfusion status of chronically dysfunctional yet viable myocardium. Studies investigating the pathophysiology of this condition have reached different conclusions, with some suggesting that myocardial blood flow (MBF) in these regions is normal at rest with regional dysfunction resulting from repetitive stress-induced ischemia (stunned myocardium), whereas others have proposed that MBF is chronically reduced at rest (hibernating myocardium). However, adequately powered experimental studies investigating this question in an appropriate animal model using clinically available techniques have not been performed. Based on the mixed results of prior studies, we hypothesized that these chronically dysfunctional yet viable regions may actually represent a mixture of hibernation and stunning. Consequently, the purpose of this study was to quantitatively determine the distribution of MBF in left ventricular regions with chronically impaired resting function but preserved viability in a large population of animals with single-vessel coronary stenosis in an attempt to further elucidate the mechanism(s) responsible for chronic, reversible myocardial dysfunction. Methods. Fifty-two adult mini-swine with 90% proximal left circumflex (LCx) stenosis underwent dynamic positron emission tomography (PET) with 13N-ammonia and 18F-fluorodeoxyglucose and dobutamine stress echocardiography (DSE) (5 to 40 μg/kg/min) 1 month after stenosis creation. Values of MBF and FDG uptake by PET and wall motion score index (WMSI) by DSE were compared using a standard 16-segment model. Results. Of 312 possible LCx segments seen on PET, 303 (97.1%) were visualized by DSE. Of the 303 LCx segments, 279 (92.1%) had rest dysfunction (WMSI ≥ 2) by DSE. One hundred eighty-two segments (60.1%) had decreased (< 85% reference) MBF at rest with preserved to increased (> 60% reference) FDG uptake and were classified as hibernating. Ninety-two segments (30.4%) had preserved MBF (≥ 85% reference) and were classified as stunned. Five segments (1.7%) with reduced (≤ 60% reference) FDG uptake by PET and akinesis or dyskinesis at rest (WMSI ≥ 3) and no contractile reserve were considered infarcted. Hibernating segments had significantly higher FDG uptake at rest (360.7 ± 48.3 vs 212.3 ± 17.7% septal values; p < 0.001) than stunned segments consistent with greater resting ischemia. Likewise, mean rest WMSI was also worse in hibernating versus stunned segments (2.35 ± 0.04 vs 2.13 ± 0.04; p < 0.001). There was no difference in the percentage of hibernating versus stunned segments exhibiting contractile reserve during dobutamine infusion (55.5 vs 63.7%; p = 0.4), indicating similar degrees of viability. Conclusions. Myocardial hibernation and stunning appear to frequently coexist in regions served by a stenotic coronary vessel. Hibernating regions appear to have greater resting ischemia based on higher values of FDG uptake and greater resting dysfunction. Reversible left ventricular dysfunction in the setting of chronic coronary artery disease is likely due to a combination of these two mechanisms.

Positron emission tomography scanning in the evaluation of hepatocellular carcinoma

Background/Aims: 18F-fluorodeoxyglucose uptake allows estimation of glucose metabolism by tumor cells using positron emission tomography (PET). We evaluated the role of PET imaging in the diagnosis of hepatocellular carcinoma. Methods: PET images were collected after intravenous injection of 8–12 mCi of 18F-FDG in 20 patients with hepatocellular carcinoma (HCC). PET tumor activity level was assessed on a scale of 1 to 4 compared to normal liver tissue. The PET score was compared with abdominal computerized tomography (CT) scan results and between tumors of different grades and differentiation. Results: Of the 20 patients studied, 11 (55%) had positive PET scans (PET score: 3 or 4) while nine (45%) were negative (PET score: 1 or 2). CT scan was positive in 18 patients (90%) and negative in two (10%). PET, however, revealed metastases in three patients that were not seen on CT. On pathological review, well-differentiated and low-grade tumors had lower PET scores. Comparison of the well-differentiated with the moderately- and poorly-differentiated tumors revealed a statistically significant difference. No statistical significance was observed between the moderately- and poorly-differentiated tumors or between different tumor grades and PET scores. Conclusions: The sensitivity of PET in diagnosis of HCC was 55% compared to 90% for CT scanning, although only PET detected some tumors (including distant metastases). Well-differentiated and low tumor grades had lower activity on PET and correspondingly lower PET scores. PET imaging may help assess tumor differentiation and may be useful in the diagnosis and staging and prognostication of HCC as an adjunct to CT.