Purpose The aim of the study was to evaluate the prognostic significance of intratumoral metabolic heterogeneity on pretreatment 18F-FDG PET/CT in patients with lung cancer who were pathologically N0 (pN0) after curative surgical resection. Methods We examined 119 patients (M/F = 79/40; mean age, 64.6 ± 9.0 years) who had undergone pretreatment 18F-FDG PET/CT and were diagnosed as pN0 after curative surgery for adenocarcinoma (ADC; n = 67) or squamous cell carcinoma (SQCC; n = 52). Heterogeneity factor (HF) and other metabolic parameters (SUVmax, metabolic tumor volume [MTV] and total lesion glycolysis [TLG]) for the primary lesions were measured, and the results were analyzed for recurrence. The HF, defined as the derivative of the volume-threshold function from 20% to 80%, was computed for primary lesions. Univariate and multivariate analyses for recurrence were performed using the Kaplan-Meier method and using the Cox proportional hazards model. Results SUVmax, MTV, TLG, and HF were statistically different between patients with ADC and SQCC. Forty-one (34.5%) of 119 patients experienced recurrence (ADC, 25/67 = 37.3% vs. SQCC, 16/52 = 30.8%). Results of univariate analysis indicate that SUVmax, MTV, TLG, and HF in ADC and TLG and HF in SQCC were predictors for recurrence. After adjusting for sex, age, and histological grade in multivariate analysis, high SUVmax, MTV, TLG, and HF in ADC exhibited an association with increased risk of recurrence. Conclusions Metabolic parameters and heterogeneity of primary tumor on pretreatment 18F-FDG PET/CT can predict recurrence in pN0 NSCLC patients of ADC type who have undergone curative surgery but not in patients of SQCC type.

Radioiodine is highly specific for detecting functioning thyroid tissue in the body. However, an unexpected radioiodine uptake can cause various false-positive results in whole-body scanning. We report a case of a 47-year-old woman who showed strong and focal uptake in the right pelvic area suggesting metastasis on the posttreatment whole-body scan. SPECT/CT revealed that the uptake was located in the colon, and the uptake was completely egested after additional bowel preparation.

BACKGROUND:The aim of this study was to investigate risk factors for recurrence in patients with lung adenocarcinoma (LAD) who were pathologically N0 (pN0) after curative surgical resection.METHODS:A total of 102 LAD patients (M/F = 55/47, mean age, 62.6 ± 9.4 years) diagnosed as pN0 after curative surgery were included in this study. Clinical, biochemical, radiologic, and pathologic findings were reviewed and analyzed for recurrence. Metabolic parameters [SUVmax, metabolic tumor volume (MTV), total lesion glycolysis (TLG)] on pretreatment F-18 FDG PET/CT were also obtained and analyzed for recurrence.RESULTS:Of 102 patients, 38 (37.3%) were found to experience recurrence for 33.6 ± 16.3 months. SUVmax, MTV, and TLG were significantly higher in patients with recurrence. The optimal cutoff values determined using a receiver-operating characteristic curve were 6.90 for SUVmax, 10.78 cm(3) for MTV, and 39.68 for TLG. Univariate analysis showed that tumor size, tumor marker, SUVmax, MTV, and TLG were prognostic factors for recurrence. In multivariate analyses, after adjusting for age, sex, tumor size, pathologic T stage, and tumor marker, high SUVmax, MTV, and TLG showed an association with an increased risk of recurrence.CONCLUSIONS:Metabolic parameters on pretreatment F-18 FDG PET/CT can predict recurrence in pN0 LAD patients who underwent curative surgery. Therefore, patients with high metabolic parameters on PET can be considered as candidates for adjuvant therapy to reduce recurrence and should be monitored carefully for early detection of possible recurrence.

We investigated whether the whole-body metabolic tumour volume (WBMTV) measured by 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can improve the prediction of prognosis in patients with small cell lung cancer (SCLC).

PURPOSE The purpose of this study was to suggest a new diagnostic strategy using metabolic volume (MV) and maximum standardized uptake value (SUVmax) to differentiate malignancy and dysplasia from benign colonic 2-deoxy-2-18F-fluoro-D-glucose (FDG) uptakes. MATERIALS AND METHODS From records of 21,317 consecutive FDG positron emission tomography/computed tomography (PET/CT) scans at 2 centers, 102 focal colonic lesions in 99 patients investigated by colonoscopy and histopathologic examination were eligible for this retrospective study. SUVmax and MV were compared according to colonoscopic and histopathologic results. Firstly, dysplasia was separated from malignancy and benign lesions. Secondly, malignancy and benign lesions were separated from each other. The better parameters of each step were determined, and a diagnostic strategy was developed from their combination. RESULTS A total of 102 incidental colonic FDG uptakes were revealed as 32 malignancies, 43 dysplasias, and 27 benign lesions. MV better differentiated dysplasia from malignancy and benign lesions (cutoff value, ≤3.14 cm3; area under the receiver-operating characteristic curve [AUC] = 0.947), and SUVmax better differentiated malignancy from benign lesions (cutoff value, >9.1; AUC = 0.934). Overall, the stepwise algorithm using MV and SUVmax (AUC = 0.886) was superior to single measurements of SUVmax (AUC = 0.750) and MV (AUC = 0.714) for differentiating malignancy and dysplasia from benign lesions; sensitivity: 92%, specificity: 85%, accuracy: 90%, positive predictive value: 94%, negative predictive value: 79%. CONCLUSIONS The stepwise approach using MV and SUVmax was able to differentiate malignancy and dysplasia from benign colonic FDG uptakes on PET/CT. Colonic FDG uptake with MV ≤3.14 cm3 had a high probability of dysplasia. MV >3.14 cm3 and SUVmax >9.1 indicated malignancy, whereas MV >3.14 cm3 and SUVmax ≤9.1 indicated benign lesions.

PURPOSE:The aim of this study was to compare (131)I whole-body scintigraphy (WBS), WBS with (131)I single photon emission computed tomography/computed tomography (SPECT/CT), and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the detection of distant metastases of differentiated thyroid cancer (DTC). METHODS:A total of 140 patients with 258 foci of suspected distant metastases were evaluated. (131)I WBS, (131)I SPECT/CT, and (18)F-FDG PET/CT images were interpreted separately. The final diagnosis was obtained from histopathologic study, serum thyroglobulin level, other imaging modalities, and/or clinical follow-up. RESULTS:Of the 140 patients with 258 foci, 46 patients with 166 foci were diagnosed as positive for distant metastasis. The sensitivity, specificity, and diagnostic accuracy of each imaging modality were 65, 55, and 59%, respectively, for (131)I WBS; 65, 95, and 85% for (131)I SPECT/CT, respectively; and 61, 98, and 86%, respectively, for (18)F-FDG PET/CT in patient-based analyses. Lesion-based analyses demonstrated that both SPECT/CT and PET/CT were superior to WBS (p<0.001) in all patient groups. SPECT/CT was superior to WBS and PET/CT (p<0.001) in patients who received a single challenge of radioiodine therapy, whereas PET/CT was superior to WBS (p=0.005) and SPECT/CT (p=0.013) in patients who received multiple challenges. CONCLUSION:Both SPECT/CT and PET/CT demonstrated high diagnostic performance in detecting metastatic thyroid cancer. SPECT/CT was highly accurate in patients who underwent a single challenge of radioiodine therapy. In contrast, (18)F-FDG PET/CT presented the highest diagnostic performance in patients who underwent multiple challenges of radioiodine therapy.