Routine use of dual time 18F-FDG PET for staging of preoperative lung cancer: does it affect clinical management?

Objective

The objective of this study was to compare the diagnostic accuracy of dual-time-point 18F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) to single-time-point ¹⁸F-FDG PET for staging of preoperative lung cancer.

Methods

Between November 2008 and December 2009, 107 patients who were diagnosed as having lung cancer or strongly suspected of having lung cancer were enrolled. They underwent dual-time-point ¹⁸F-FDG PET following conventional imaging. Dual-time-point ¹⁸F-FDG PET imaging (whole body) was performed at 1-h (early) post-FDG injection and repeated (2 h delayed) after injection. The diagnostic accuracy of pre-PET staging and post-PET staging was retrospectively evaluated, and the diagnostic accuracy of dual-time-point ¹⁸F-FDG PET was compared to that of single-time-point ¹⁸F-FDG PET.

Results

In 100 patients, the early ¹⁸F-FDG PET scan resulted in upstaging of the tumor in ten (10 %) and down-staging of the tumor in five (5 %) compared to the conventional scan. The delayed phase of ¹⁸F-FDG PET provided no additional information on staging for lung cancer patients. The remaining seven patients were diagnosed as not having lung cancer.

Conclusion

This study confirmed that dual-time-point ¹⁸F-FDG PET is useful for differential diagnosis between benign and malignant lesions, but has no major impact on staging and therapeutic management of patients with pathologically proven lung cancer.     

Perfusion-metabolism coupling in recurrent gliomas: a prospective validation study with 13N-ammonia and 18F-fluorodeoxyglucose PET/CT

Introduction

We assessed the validity of “perfusion-metabolism coupling” hypothesis in recurrent glioma with ¹³N-ammonia (¹³N-NH₃) PET/CT and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/CT.

Methods

Fifty-six consecutive patients (age, 38.8?±?12.1 years; 62.5 % males) with histologically proven and previously treated glioma presenting with clinical suspicion of recurrence were prospectively enrolled and evaluated with ¹³N-NH₃ PET/CT and ¹⁸F-FDG PET/CT. PET/CT images were evaluated both qualitatively and semiquantitatively. Tumor to white matter uptake ratio (T/W) and tumor to gray matter uptake ratio (T/G) were calculated and analyzed for both the modalities. A combination of clinico-radiological follow-up, repeated imaging, and biopsy (when available) were considered as the reference standard.

Results

Based on the reference standard, 27/56 patients had recurrence. ¹³N-NH₃ PET/CT and ¹⁸F-FDG PET/CT were concordant in 55/56 patients. Overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ¹³N-NH₃PET/CT were 77.8, 86.2, 84.0, 80.7, and 82.1 %, respectively, and for ¹⁸F-FDG PET/CT were 77.8, 89.7, 87.5, 81.2, and 83.9 %, respectively. There was excellent agreement between results of ¹³N-NH₃ PET/CT and ¹⁸F-FDG PET/CT (??=?0.964; P?13N-NH₃ PET/CT and ¹⁸F-FDG PET/CT were not significantly different between high-grade and low-grade glioma (P?=?1.000). A strong positive correlation was noted between the uptake ratios derived on the two modalities (ρ?=?0.866, P?ρ?=?0.918, P?Conclusion A combination of ¹³N-NH₃ PET/CT and ¹⁸F-FDG PET/CT demonstrates that perfusion and metabolism are coupled in recurrent gliomas. These tracers target two different but interrelated aspects of the same pathologic process and can be used as surrogates for each other.     

Comparison of the prognostic values of 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT in patients with well-differentiated neuroendocrine tumor

Purpose

To determine the prognostic value of ⁶⁸Ga-DOTANOC PET/CT in patients with well-differentiated neuroendocrine tumor (NET), and to compare the prognostic value with that of ¹⁸F-FDG PET/CT and other conventional clinicopathological prognostic factors.

Methods

Data from 37 consecutive patients (age 46.6?±?13.5 years, 51 % men) with well-differentiated NET who underwent ⁶⁸Ga-DOTANOC PET/CT and ¹⁸F-FDG PET/CT were analyzed. All patients underwent a baseline visit with laboratory and radiological examinations. Clinical and imaging follow-up was performed in all patients. Progression-free survival (PFS) was measured from the date of the first PET/CT scan to the first documentation of progression of disease.

Results

⁶⁸Ga-DOTANOC PET/CT was positive in 37 of the 37 patients and ¹⁸F-FDG PET/CT was positive in 21. During follow-up 10 patients (27 %) showed progression of disease and 27 (73 %) showed no progression (24 stable disease, 3 partial response). The median follow-up was 25 months (range 2 – 52 months). Among the variables evaluated none was significantly different between the progressive disease and nonprogressive disease groups, with only SUVmax on ⁶⁸Ga-DOTANOC PET/CT being borderline significant (P?=?0.073). In the univariate analysis for PFS outcome, SUVmax on ⁶⁸Ga-DOTANOC PET/CT (HR 0.122, 95 % CI 0.019 – 0.779; P?=?0.026) and histopathological tumor grade (HR 4.238, 95 % CI 1.058 – 16.976; P?=?0.041) were found to be associated with PFS. Other factors including age, sex, primary site, Ki-67 index, TNM stage, ¹⁸F-FDG PET/CT status (positive/negative), SUVmax on ¹⁸F-FDG PET/CT and type of treatment were not significant. In multivariable analysis, only SUVmax on ⁶⁸Ga-DOTANOC PET/CT was found to be an independent positive predictor of PFS (HR 0.122, 95 % CI 0.019 – 0.779; P?=?0.026).

Conclusion

SUVmax measured on ⁶⁸Ga-DOTANOC PET/CT is an independent, positive prognostic factor in patients with well-differentiated NET and is superior to SUVmax on ¹⁸F-FDG PET/CT and conventional clinicopathological factors for predicting PFS.     

Performance of FDG PET/CT at initial diagnosis in a rare lymphoma: nodular lymphocyte-predominant Hodgkin lymphoma

Purpose

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare Hodgkin lymphoma distinguished from classical Hodgkin lymphoma (cHL) by the nature of the neoplastic cells which express B-cell markers. We wanted to determine the diagnostic performance of FDG PET/CT in initial assessment and its therapeutic impact on staging.

Methods

We retrospectively studied a population of 35 patients with NLPHL (8 previously treated for NLHPL, 27 untreated). All patients underwent an initial staging by pretherapeutic FDG PET/CT. The impact on initial stage or relapse stage was assessed by an independent physician.

Results

In a per-patient analysis, the sensitivity of the pretherapeutic FDG PET/CT was 100 %. In a per-site analysis, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of pretherapeutic FDG PET/CT were 100 %, 99 %, 97 %, 100 % and 99 %, respectively. Pretherapeutic FDG PET/CT led to a change in the initial stage/relapse stage in 12 of the 35 patients (34 %). In contrast to previous results established without FDG PET/CT, 20 % of patient had osteomedullary lesions.

Conclusion

Pretherapeutic FDG PET/CT has excellent performance for initial staging or relapse staging of NLPHL.     

Role of [18F]FDG PET in prediction of KRAS and EGFR mutation status in patients with advanced non-small-cell lung cancer

Purpose

The tumour molecular profile predicts the activity of epidermal growth factor receptor (EGFR) inhibitors in non-small-cell lung cancer (NSCLC). However, tissue availability and tumour heterogeneity limit its assessment. We evaluated whether [¹⁸F]FDG PET might help predict KRAS and EFGR mutation status in NSCLC.

Methods

Between January 2005 and October 2011, 340 NSCLC patients were tested for KRAS and EGFR mutation status. We identified patients with stage III and IV disease who had undergone [¹⁸F]FDG PET/CT scanning for initial staging. SUVpeak, SUVmax and SUVmean of the single hottest tumour lesions were calculated, and their association with KRAS and EGFR mutation status was assessed. A receiver operator characteristic (ROC) curve analysis and a multivariate analysis (including SUVmean, gender, age and AJCC stage) were performed to identify the potential value of [¹⁸F]FDG PET/CT for predicting KRAS mutation.

Results

From 102 patients staged using [¹⁸F]FDG PET/CT, 28 (27 %) had KRAS mutation (KRAS+), 22 (22 %) had EGFR mutation (EGFR+) and 52 (51 %) had wild-type KRAS and EGFR profiles (WT). KRAS+ patients showed significantly higher [¹⁸F]FDG uptake than EGFR+ and WT patients (SUVmean 9.5, 5.7 and 6.6, respectively; p?18F]FDG uptake between EGFR+ patients and WT patients. ROC curve analysis for KRAS mutation status discrimination yielded an area under the curve of 0.740 for SUVmean (p?Conclusion NSCLC patients with tumours harbouring KRAS mutations showed significantly higher [¹⁸F]FDG uptake than WT patients, as assessed in terms of SUVpeak, SUVmax and SUVmean. A multivariate model based on age, gender, AJCC stage and SUVmean might be used as a predictive marker of KRAS mutation status in patients with stage III or IV NSCLC.     

The diagnostic role of 18F-FDG PET for primary central nervous system lymphoma

Objective

¹⁸F-FDG PET has become one of the most important methods for studying malignant lymphoma, but its diagnostic role for primary central nervous system lymphoma (PCNSL) has not been established. The aim of this study was to determine the appropriate cut-off values of FDG uptake and to investigate how corticosteroid administration influences PCNSL.

Methods

We retrospectively reviewed 82 patients with contrast-enhanced brain tumors who underwent an FDG PET scan at onset, including 19 PCNSLs. FDG uptake of the lesion was assessed by the maximum standardized uptake value (SUVmax) and the ratio of tumor to normal contralateral cortex activity (T/N ratio). Receiver operating characteristic (ROC) curves were generated from the SUVmax and T/N ratios. To investigate the influence of corticosteroid application before a FDG PET scan, we evaluated the association between the FDG uptake of the lesion and the cumulative dose of corticosteroid administration on 13 PCNSL patients who had received steroid treatment before an FDG PET examination.

Results

The mean FDG SUVmax and T/N ratio of PCNSLs were 22.6 and 2.79, respectively, and these values were significantly higher than those of the other malignant brain tumors. ROC analysis indicated that the evaluation of FDG uptake using the T/N ratio was more reliable than the SUVmax with respect to the differential diagnosis. When PCNSL patients went without steroid application before FDG PET, the accuracy of the T/N ratio with a cut-off point of 2.0 was 91.1 %, the sensitivity was 94.7 %, and the specificity was 87.3 %. Although there are no significant differences in the FDG T/N ratio for PCNSL patients with or without steroid treatment, a negative correlation was found between the T/N ratio and cumulative dose of corticosteroid before PET study (r = ?0.71, p = 0.032).

Conclusions

We concluded that the T/N ratio was superior to SUVmax for FDG uptake assessment as for distinguishing PCNSLs from other malignant brain tumors; the appropriate T/N ratio cut-off point was 2.0. In addition, FDG uptake could be influenced by cumulative doses of corticosteroid before a PET scan, and thus this fact should be taken into consideration when evaluating FDG PET for PCNSL diagnosis.     

What parameters from 18F-FDG PET/CT are useful in evaluation of adrenal lesions?

Purpose

Prior studies have suggested that ¹⁸F-FDG PET/CT can help characterize adrenal lesions and differentiate adrenal metastases from benign lesions. The aim of this study was to assess the value of ¹⁸F-FDG PET/CT for the differentiation of malignant from benign adrenal lesions.

Methods

This retrospective study included 85 patients (47 men and 38 women, age 63.8?±?10.8 years) who had undergone ¹⁸F-FDG PET/CT (60 min after injection 300 – 370 MBq ¹⁸F-FDG; Biograph 64 scanner) for evaluation of 102 nonsecreting adrenal masses. For semiquantitative analysis, the maximum standardized uptake value (SUVmax), adrenal to liver (T/L) SUVmax ratio, mean CT attenuation value and tumour diameter were measured in all lesions and compared with the pathological findings.

Results

Malignant adrenal tumours (68 % of evaluated tumours) had a significantly higher mean SUVmax (13.0?±?7.1 vs. 3.7?±?3.0), a higher T/L SUVmax ratio (4.2?±?2.6 vs. 1.0?±?0.9), a higher CT attenuation value (31.9?±?16. 7 HU vs. 0.2?±?25.8 HU) and a greater diameter (43.6?±?23.7 mm vs. 25.6?±?13.3 mm) than benign lesions. The false-positive findings were tuberculosis and benign phaeochromocytoma. Based on ROC analysis, a T/L SUVmax ratio >1.53, an adrenal SUVmax >5.2, an attenuation value >24 HU and a tumour diameter >30 mm were chosen as the optimal cut-off values for differentiating malignant from benign tumours. The areas under the ROC curves for the selected cut-off values were 0.96, 0.96, 0.88 and 0.77, respectively. A multivariate logistic regression model revealed that the T/L SUVmax ratio was an independent prognostic factor for malignancy (p?25 HU and a tumour diameter >30 mm had no additional individual importance in the diagnosis of malignancy.

Conclusion

Using a T/L SUVmax ratio >1.53 and an adrenal SUVmax >5.2 in ¹⁸F-FDG PET/CT led to high diagnostic sensitivity, specificity and negative predictive value for characterizing adrenal tumours. The diagnostic accuracies of the two parameters were comparable, but T/L SUVmax ratio was an independent predictor of malignancy.     

Impact of 18F-FDG PET/CT on the management of adrenocortical carcinoma: analysis of 106 patients

Purpose

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy. Limited data are available about on value of ¹⁸F-FDG PET/CT in ACC. We evaluated the impact of PET/CT on the management of ACC.

Methods

We performed a retrospective review in patients with ACC who had undergone PET/CT. The impact of PET/CT on the management plan was evaluated by comparing the findings on PET/CT to the findings on contrast-enhanced CT. The sensitivity, specificity, and accuracy of each form of imaging were calculated. The correlations between PET/CT parameters, including maximum standardized uptake value (SUV_max), total lesion glycolysis, and decline in SUV_max after chemotherapy, and clinical outcome were evaluated.

Results

Included in the analysis were 106 patients with 180 PET/CT scans. Of the 106 patients, 7 underwent PET/CT only for initial staging, 84 underwent PET/CT only for restaging, and 15 underwent PET/CT for both initial staging and restaging. PET/CT changed the management plan in 1 of 22 patients (5 %) at initial staging and 9 of 99 patients (9 %) at restaging. In 5 of the patients in whom PET/CT changed the management plan, PET/CT showed response to chemotherapy but contrast-enhanced CT showed stable disease. Sensitivity, specificity, and accuracy were 100 %, 100 %, and 100 % for PET/CT at initial staging; 92.6 %, 100 %, and 96.4 % for CT at initial staging; 98.4 %, 100 %, and 99.5 % for PET/CT at restaging; and 96.8 %, 98.6 %, and 98.0 % for CT at restaging, respectively. No PET/CT parameters were associated with survival at either initial diagnosis or recurrence.

Conclusion

PET/CT findings could substantially change the management plan in a small proportion of patients with ACC. Although lesion detection was similar between PET/CT and CT, PET/CT may be preferred for chemotherapeutic response assessment because it may predict response before anatomic changes are detected on CT.     

F-18 FDG PET/CT in the evaluation of Takayasu arteritis: An experience from the tropics

Objective

To evaluate the performance parameters of FDG PET/CT in patients with Takayasu arteritis at diagnosis and during immunosuppression.

Methods

Retrospective analysis of 60 FDG PET/CT studies in 51 patients was performed (17 scans at diagnosis out of which 4 had follow-up scans also and 43 scans on immunosuppression). The degree of FDG uptake in the vessels was assessed visually using a 4-point scale and maximum standardized uptake value (SUVmax), SUVratio, extent of vasculitis and association with ESR were calculated.

Results

PET/CT was positive for active vasculitis in all 17 patients at diagnosis. The mean SUVmax and mean SUV ratio of the active areas were 5.1 ± 3.0 and 3.2 ± 1.9, respectively. On immunosuppression, PET scan was positive for active vasculitis in 14/43 (32.5%) scans. The mean SUVmax and mean SUVratio of the active areas were 1.7 ± 2.1 and 0.95 ± 1.2, respectively. There was significant difference between the mean SUVmax and mean SUVratio at diagnosis and on immunosuppression, respectively (P < .01). The median number of vascular segments in each uptake grade group was also statistically different (P < .01) between scans at diagnosis and on immunosuppression. The median ESR level in PET positive scans was 29 mm/hour (2-53), whereas in PET negative scans was 35.5 mm/hour (6-50) and the difference was not statistically significant.

Conclusion

FDG PET/CT showed good sensitivity to detect active vasculitis at diagnosis and during immunosuppression. The change in SUVmax between the successive FDG PET/CT scans may give an objective assessment of response to immunosuppression.     

18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT,radiography and clinical parameters

Purpose

The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with ¹⁸F-FDG.

Methods

Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological ¹⁸F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features.

Results

Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73?±?7.7 years). Six patients served as the control group (53.7?±?9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r?=?0.86. p??=?0.007; r?=?0.94, p?=?0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7?±?6.6 vs. 32.2?±?0.4, p?=?0.02; 37.5?±?5.4 vs. 32.2?±?0.4, p?=?0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8?±?4.2 vs. 18?±?1.8, p?=?0.13; 22.8?±?5.38 vs. 20.1?±?1.54, p=?0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9?±?31.3 vs. 0, p?=?0.03).

Conclusion

Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted.     

Pretherapy metabolic tumour volume is an independent predictor of outcome in patients with diffuse large B-cell lymphoma

Purpose

We investigated the prognostic value of total metabolic tumour volume (TMTV) in diffuse large B-cell lymphoma (DLBCL).

Methods

TMTV was measured in 114 patients with newly diagnosed DLBCL who underwent ¹⁸F-FDG PET/CT at baseline before immunochemotherapy. TMTV was computed by summing the volumes of all lymphomatous lesions after applying the local SUVmax threshold of 41 % using semiautomatic software. Prognostic value was assessed by Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS).

Results

Median follow-up was 39 months. Average pretherapy TMTV was 509?±?568 cm³. The 3-year estimates of PFS were 77 % in the low metabolic burden group (TMTV ≤550 cm³) and 60 % in the high metabolic burden group (TMTV >550 cm³, p?=?0.04), and prediction of OS was even better (87 % vs. 60 %, p?=?0.0003). Cox regression showed independence of TMTV for OS prediction (p?=?0.002) compared with other pretherapy indices of tumour burden, such as tumour bulk and the International Prognostic Index.

Conclusion

Pretherapy TMTV is an independent predictor of outcome in patients with DLBCL.     

The role of metabolic tumor volume and total lesion glycolysis on 18F-FDG PET/CT in the prognosis of epithelial ovarian cancer

Purpose

This study assessed the prognostic value of pre-operative 2-[¹⁸F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) volumetric parameters, including metabolic tumor volume (MTV) and total lesion glycolysis (TLG), in patients with epithelial ovarian cancer.

Methods

A total of 175 patients with epithelial ovarian cancer who underwent ¹⁸?F-FDG PET/CT and subsequent cytoreductive surgery were retrospectively enrolled. Maximum standardized uptake value (SUVmax) on ¹⁸F-FDG PET/CT was measured for all patients. Because nine patients showed low tumor-to-background uptake ratios, MTV and TLG were measured in 166 patients. Univariate and multivariate analyses were performed to evaluate the prognostic significance of SUVmax, MTV, TLG, and clinicopathological factors for disease progression-free survival.

Results

Disease progressed in 78 (44.6 %) of the 175 patients, and the 2-year disease progression-free survival rate was 57.5 %. Univariate analysis showed that tumor stage, histopathological type, presence of regional lymph node metastasis, residual tumor after cytoreductive surgery, pre-operative serum carbohydrate antigen 125 (CA125) level, SUVmax, MTV, and TLG were significant prognostic factors (p?100.0).

Conclusion

Along with tumor stage, TLG is an independent prognostic factor for disease progression after cytoreductive surgery in patients with epithelial ovarian cancer. By combining tumor stage and TLG, one can further stratify the risk of disease progression for patients undergoing cytoreductive surgery.     

Quantitative interpretation of FDG PET/CT with myocardial perfusion imaging increases diagnostic information in the evaluation of cardiac sarcoidosis

Background

FDG PET/CT with myocardial perfusion imaging is a useful method for evaluating cardiac sarcoidosis (CS), but interpretation is not standardized. We developed a method for quantification of cardiac FDG PET/CT and evaluated its relationship to conventional interpretation, perfusion defects, clinical events, and immunosuppressive treatment.

Methods and Results

FDG PET/CT with MPI studies performed for CS (n = 38) were retrospectively compared to negative control studies acquired for oncologic indications (n = 10). Quantitative measures of FDG volume-intensity (Cardiac Metabolic Activity, CMA) was performed using standardized uptake values (SUVs). CMA (477.7 ± 909 vs 0.55 ± 2.1 vs 0.3 ± 0.3 g glucose, P = .02) was significantly greater in visually FDG-positive studies compared to visually negative and oncologic negative studies. Among patients with CS, CMA was greater in studies with an EF < 50% (760.3 ± 1,148 vs 87.4 ± 161 g glucose, P = .03) and preceding an adverse clinical event (1,095 ± 1,253 vs 73 ± 144 g glucose, P = .006). CMA was the only independent predictor of events by multivariate analysis. In patients with repeat examinations (n = 7), CMA decreased with prednisone treatment in 5 of 6 patients.

Conclusions

Quantification of FDG uptake in CS correlates with lower EFs, clinical events, and immunosuppression treatment.     

In-vivo monitoring of erythropoietin treatment after myocardial infarction in mice with [68Ga]Annexin A5 and [18F]FDG PET

Background

Several studies substantiate the cardioprotective effects of erythropoietin (EPO). Our goal was to quantify the effects of EPO treatment on the early expression of the apoptosis marker phosphatidylserine as well as on the left ventricular volumes and function by means of small animal PET.

Methods and Results

Myocardial infarction (MI) was induced in C57BL/6 mice. Animals were assigned to saline or EPO groups and underwent Annexin PET (day 2) and gated FDG PET (days 6 and 30). Annexin uptake was significantly higher in the infarction than in remote myocardium, with no differences between treatment groups. Infarct size showed a slight decrease in the EPO group and a slight increase in the controls, which did not reach statistical significance. Follow-up analyses revealed a significant increase of end-diastolic and end-systolic volumes in the EPO group, in which a stable left ventricular ejection fraction (LVEF) was maintained.

Conclusion

We find that deleterious effects of EPO can outweigh cardioprotective effects. The present EPO treatment did not significantly reduce apoptosis after MI, but seemingly provoked significant myocardial dilation while maintaining a stable LVEF. Molecular mechanisms of EPO treatment may need further elucidation to optimize therapy regimens.     

18F-FDG PET-CT uptake is a feature of both normal diameter and aneurysmal aortic wall and is not related to aneurysm size

Purpose

Aortic metabolic activity is suggested to correlate with presence and progression of aneurysmal disease, but has been inadequately studied. This study investigates the 2-[¹⁸F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) uptake in a population of infra-renal abdominal aortic aneurysms (AAA), compared to a matched non-aneurysmal control group.

Methods

The Positron Emission Tomography – Computed Tomography (PET/CT) database was searched for infra-renal AAA. Exclusion criteria were prior repair, vasculitis, and saccular/mycotic thoracic or thoraco-abdominal aneurysms. Matching of 159 non-aneurysmal (<3 cm diameter) controls from the same population was assessed. Infra-renal aortic wall FDG uptake was assessed using visual analysis; maximum standardized uptake value (SUV_max) and target to background mediastinal blood pool ratio (TBR) were documented. Predictors of FDG uptake (age, sex, aortic diameter, hypertension, statin use, and diabetes) were assessed using univariate analysis. Follow-up questionnaires were sent to referring clinicians.

Results

Aneurysms (n?=?151) and controls (n?=?159) were matched (p?>?0.05) for age, sex, diabetes, hypertension, smoking status, statin use, and indication for PET/CT. Median aneurysm diameter was 5.0 cm (range 3.2–10.4). On visual analysis there was no significant difference in the overall numbers with increased visual uptake 24 % (36/151) in the aneurysm group vs. 19 % (30/159) in the controls, p?=?ns. SUV_max was slightly lower in the aneurysm group vs. controls (mean (2 SD) 1.75(0.79) vs. 1.84(0.58), p?=?0.02). However there was no difference in TBR between the AAA group and controls (mean (2 SD) 1.03 (0.46) vs. 1.05(0.31), p?=?0.36). During a median 18 (interquartile range 8–35) months’ follow-up 20 were repaired and four were confirmed ruptured.

Conclusions

The level of metabolic activity as assessed by ¹⁸F-FDG PET/CT in infra-renal AAA does not correlate with aortic size and does not differ between aneurysms and matched controls.     

Metabolic parameters using 18F-FDG PET/CT correlate with occult lymph node metastasis in squamous cell lung carcinoma

Purpose

The aim of this study was to investigate predictability of occult lymph node metastasis (OLM) using metabolic parameters on pretreatment ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/CT in squamous cell non-small cell lung carcinoma (SC-NSCLC) patients who were clinically node negative (cN0) before surgery.

Methods

A total of 63 cN0 SC-NSCLC patients (M/F = 61/2, mean age 64.1?±?8.0) who underwent curative surgery with lymph node dissection were enrolled in this study. Metabolic tumor volume (MTV) of the primary tumor was obtained with a standardized uptake value (SUV) threshold of 2.5. Total lesion glycolysis (TLG) was calculated by multiplication of the MTV and its SUV_mean. Metabolic parameters (SUV_max, MTV, and TLG) and clinicopathological factors were analyzed for OLM.

Results

Of 63 patients, 12 (19.0 %) had OLM. Significantly higher SUV_max, MTV, TLG, and pathological tumor size were observed in patients with OLM. The optimal cutoff values for prediction of OLM determined using a receiver-operating characteristic (ROC) curve were 8.8 for SUV_max, 18.9 cm³ for MTV, 88.4 for TLG, and 2.8 cm for pathological tumor size. Univariate analysis showed correlation of SUV_max, MTV, and TLG with the rate of OLM. In multivariate analyses, high SUV_max and MTV showed an association with an increased risk of OLM, after adjusting for age, sex, pathological tumor size, T stage, and location.

Conclusion

Metabolic parameters on pretreatment ¹⁸F-FDG PET/CT were significant predictors for OLM in cN0 SC-NSCLC patients. Surgical planning can be tailored based on the parameters in order to reduce the risk of hidden residual lymph node metastases in patients.     

Comparison of choline-PET/CT,MRI, SPECT,and bone scintigraphy in the diagnosis of bone metastases in patients with prostate cancer: a meta-analysis

Published data on the diagnosis of bone metastases of prostate cancer are conflicting and heterogeneous. We performed a comprehensive meta-analysis to compare the diagnostic performance of choline-PET/CT, MRI, bone SPECT, and bone scintigraphy (BS) in detecting bone metastases in parents with prostate cancer. Pooled sensitivity, specificity, and diagnostic odds ratios (DOR) were calculated both on a per-patient basis and on a per-lesion basis. Summary receiver operating characteristic (SROC) curves were also drawn to obtain the area under curve (AUC) and Q* value. Sixteen articles consisting of 27 studies were included in the analysis. On a per-patient basis, the pooled sensitivities by using choline PET/CT, MRI, and BS were 0.91 [95 % confidence interval (CI): 0.83–0.96], 0.97 (95 % CI: 0.91–0.99), 0.79 (95 % CI: 0.73–0.83), respectively. The pooled specificities for detection of bone metastases using choline PET/CT, MRI, and BS, were 0.99 (95 % CI: 0.93–1.00), 0.95 (95 % CI: 0.90–0.97), and 0.82 (95 % CI: 0.78–0.85), respectively. On a per-lesion basis, the pooled sensitivities of choline PET/CT, bone SPECT, and BS were 0.84 (95 % CI: 0.81–0.87), 0.90 (95 % CI: 0.86–0.93), 0.59 (95 % CI: 0.55–0.63), respectively. The pooled specificities were 0.93 (95 % CI: 0.89–0.96) for choline PET/CT, 0.85 (95 % CI: 0.80–0.90) for bone SPECT, and 0.75 (95 % CI: 0.71–0.79) for BS. This meta-analysis indicated that MRI was better than choline PET/CT and BS on a per-patient basis. On a per-lesion analysis, choline PET/CT with the highest DOR and Q* was better than bone SPECT and BS for detecting bone metastases from prostate cancer.     

Value of 18F-FDG uptake on PET/CT and CEA level to predict epidermal growth factor receptor mutations in pulmonary adenocarcinoma

Purpose

The identification of the mutation status of the epidermal growth factor receptor (EGFR) is important for the optimization of treatment in patients with pulmonary adenocarcinoma. The acquisition of adequate tissues for EGFR mutational analysis is sometimes not feasible, especially in advanced-stage patients. The aim of this study was to predict EGFR mutation status in patients with pulmonary adenocarcinoma based on ¹⁸F-fluorodeoxyglucose (FDG) uptake and imaging features in positron emission tomography/computed tomography (PET/CT), as well as on the serum carcinoembryonic antigen (CEA) level.

Methods

We retrospectively reviewed 132 pulmonary adenocarcinoma patients who underwent EGFR mutation testing, pretreatment FDG PET/CT and serum CEA analysis. The associations between EGFR mutations and patient characteristics, maximal standard uptake value (SUVmax) of primary tumors, serum CEA level and CT imaging features were analyzed. Receiver-operating characteristic (ROC) curve analysis was performed to quantify the predictive value of these factors.

Results

EGFR mutations were identified in 69 patients (52.2 %). Patients with SUVmax ≥6 (p?=?0.002) and CEA level ≥5 (p?=?0.013) were more likely to have EGFR mutations. The CT characteristics of larger tumors (≥3 cm) (p?=?0.023) and tumors with a nonspiculated margin (p?=?0.026) were also associated with EGFR mutations. Multivariate analysis showed that higher SUVmax and CEA level, never smoking and a nonspiculated tumor margin were the most significant predictors of EGFR mutation. The combined use of these four criteria yielded a higher area under the ROC curve (0.82), suggesting a good discrimination.

Conclusion

The combined evaluation of FDG uptake, CEA level, smoking status and tumor margins may be helpful in predicting EGFR mutation status in patients with pulmonary adenocarcinoma, especially when the tumor sample is inadequate for genetic analysis or genetic testing is not available. Further large-scale prospective studies are needed to validate these results.     

Right ventricular 18F-FDG uptake is an important indicator for cardiac involvement in patients with suspected cardiac sarcoidosis

Purpose

Cardiac sarcoidosis is most commonly found in the left ventricular (LV) free wall. Presence in the right ventricle (RV) is less common but might be useful for detecting cardiac involvement of sarcoidosis. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET has been used to detect LV regions with cardiac sarcoidosis. However, the same has not been done for RV involvement. The aims of the current study were to evaluate RV ¹⁸F-FDG uptake and its relationship to the distribution of LV wall ¹⁸F-FDG-positive segments in the LV, and to evaluate whether patients with positive RV ¹⁸F-FDG uptake met the 1993 diagnostic criteria of the Japanese Ministry of Health and Welfare (JMHW) guidelines regarding sarcoidosis with suspected cardiac involvement.

Method

Fifty-nine biopsy-proven extra-cardiac sarcoidosis patients (age 56.1 ± 14.7 years) with suspected cardiac involvement based on abnormal electrocardiography or echocardiography findings underwent fasting ¹⁸F-FDG PET or PET/CT. The LV wall was divided into 17 segments and RV uptake was also evaluated.

Result

Among 59 patients, 35 (59.3 %) showed some abnormal ¹⁸F-FDG uptake in the RV and/or LV wall. With respect to the RV wall, 13 (22.0 %) showed abnormal ¹⁸F-FDG uptake. The number of LV-involved segments was 4.8 ± 2.4 in the patients with RV ¹⁸F-FDG uptake, which was significantly higher than in the patients without RV uptake, 1.8 ± 2.2 (P < 0.0001). Patients with RV uptake more frequently met the diagnostic criteria of the 1993 JMHW guidelines (n = 27), than did those without RV uptake (84.6 vs. 34.8 %, P = 0.0033).

Conclusion

¹⁸F-FDG PET identified RV involvement less frequently than LV involvement in this study population. However, patients who had RV uptake showed a greater number of LV-involved segments and met the JMHW diagnostic criteria more frequently. Although RV uptake is less frequent, ¹⁸F-FDG RV uptake may be useful in diagnosing cardiac involvement in sarcoidosis.

Clinical trial registration

UMIN000006533.     

18F-Fluorocholine PET/CT for localization of hyperfunctioning parathyroid tissue in primary hyperparathyroidism: a pilot study

Purpose

Primary hyperparathyroidism is a common endocrine disorder which is diagnosed biochemically and for which therapy is surgical. A prerequisite for minimally invasive surgery, which minimizes morbidity and cost, is accurate localization of the involved gland(s). The aim of this study was to evaluate the usefulness of ¹⁸F-fluorocholine PET/CT for preoperative localization of hyperfunctioning parathyroid tissue.

Methods

¹⁸F-Fluorocholine PET/CT and conventional parathyroid scintigraphic imaging consisting of ^99mTc-sestaMIBI SPECT/CT, ^99mTc-sestaMIBI dual-phase imaging and ^99mTc-sestaMIBI/pertechnetate subtraction imaging were performed in 24 patients. The diagnostic performance of the imaging methods was compared against histology as the gold standard and postoperative serum Ca²⁺ and iPTH values.

Results

The sensitivity and specificity of ¹⁸F-fluorocholine PET/CT were 92 % and 100 %, respectively, in contrast to 49 % and 100 %, 46 % and 100 %, and 44 % and 100 % for ^99mTc-sestaMIBI SPECT/CT, ^99mTc-sestaMIBI/pertechnetate subtraction imaging and ^99mTc-sestaMIBI dual-phase imaging, respectively. Combined conventional scintigraphic imaging had a sensitivity and specificity of 64 % and 100 %, respectively. The performance of ¹⁸F-fluorocholine PET/CT was superior particularly in patients with multiple lesions or hyperplasia.

Conclusion

¹⁸F-Fluorocholine PET/CT appears to be a promising, effective imaging method for localization of hyperfunctioning parathyroid tissue.