Usefulness of central radiologic review in clinical trials of children with hepatoblastoma.

BACKGROUND: No previous research papers have reported a comparative survey of local radiologic diagnoses and central review in children with hepatoblastoma. OBJECTIVE: To evaluate the utility of central review of children with hepatoblastoma enrolled in a clinical trial. MATERIALS AND METHODS: The study included 91 children enrolled in a clinical trial conducted by the Japanese Study Group for Pediatric Liver Tumor. We compared the results of the initial pre-treatment extent of tumor (PRETEXT) disease staging performed at local sites with the results obtained on central review to determine the concurrence rates for tumor staging and additional criteria. RESULTS: The concurrence rate for PRETEXT staging was 70%. As the stage increased, the concurrence rate decreased. Using additional criteria, central review identified 143 lesions (157.1%), about 1.8 times higher than the number identified for the local site diagnoses. The additional criterion found most often on central review was "multifocal lesion" (n=19). The concurrence rate for lung metastases was high. However, our central review found many false-positive assertions of hepatic vein lesions, portal vein invasion and extrahepatic lesions among the local site diagnoses. CONCLUSION: In a clinical trial of hepatoblastoma, central review provided a more precise diagnosis than local site diagnoses with respect to severe PRETEXT stages III and IV cases and other cases including hepatic and portal vein invasion. The central review process appears to be effective and essential for improving the quality of clinical trials.

Spirometric and radiological evaluation of the remnant lung long after major pulmonary resection: can compensatory phenomena be recognized in clinical cases?

PURPOSES: The purpose of this study was to investigate the compensatory phenomena after lung resection in clinical cases by evaluating the spirometric and radiological parameters. METHODS: Forty patients undergoing lobectomy for stage IA lung cancer were divided into the following groups: (A) patients with <10 (n = 20) and (B) patients with ≥10 resected subsegments (n = 20). Comparisons were made of the predicted and observed postoperative values of spirometry and radiological parameters, such as lung volumetry and the "estimated lung weight". Predicted values were based on the number of resected subsegments. The postoperative time to re-evaluation was at least 1 year for both groups. RESULTS: The predicted postoperative values of spirometry underestimated the actual values, and the differences were more significant in group B (forced vital capacity, p = 0.006, forced expiratory volume in 1 s, p = 0.011). Focusing on the remnant lungs on the surgical side, group B had significantly larger % postoperative lung volumes (161 ± 6.0 %) and % estimated lung weight (124 ± 5.4 %) than did group A (114 ± 3.8%, p < 0.0001; 89.5 ± 4.4%, p < 0.0001, respectively). CONCLUSIONS: Major lung resection in clinical cases causes a compensatory restoration of the pulmonary function and tissue.

Predictive factors for acetabular labral lesions in osteoarthritis of the hip with radial magnetic resonance imaging--a cross-sectional study.

OBJECTIVES: To document the reliability of Abe's classification and to clarify the predictive factors for acetabular labral lesions in osteoarthritis of the hip with radial magnetic resonance (MR) imaging. METHODS: Reliability trial for the classification of acetabular labral lesion was performed by six orthopedic surgeons, grading 20 radial MR images in a blinded fashion at an interval of 4-5 weeks. Radial MR images of 275 hips in 263 patients were prospectively analyzed to determine the relationship between acetabular labral lesions, their distribution, age, and the acetabular coverage. RESULTS: Cohen's quadratic weighted kappa of inter-observer reliability was 0.784 for the grade and 0.812 for the shape category. The weighted kappa of intra-observer reliability was 0.852 for the grade and 0.90 for the shape category. Multiple regression analysis revealed that both the grade and the shape were associated with age, acetabular coverage, and location of the labrum. CONCLUSIONS: Abe's classification of labral lesions was reliable for both the grade and shape categories. Aging, acetabular dysplasia, and the anterosuperior portion would be predictive factors for degeneration of the acetabular labrum using radial MR imaging.

[A case of inverted papilloma of the renal pelvis, associated with metachronous urothelial carcinoma of the urinary bladder].

The patient visited our hospital because of macrohematuria. Cystoscopical examination did not reveal any bladder tumors but a tumor shadow in the right renal pelvis was revealed by computed tomographic scan. Urothelial carcinoma was suspected and right nephroureterectomy was performed. Pathologically the tumor was diagnosed as inverted papilloma. Four months later during the follow up of the tumor, urothelial carcinoma of the urinary bladder was detected by cystoscopy. Inverted papilloma of the renal pelvis is a rare lesion and only 39 cases to date have been reported. Because inverted papilloma of the upper urinary tract is often associated with other urothelial tumors, careful long-term follow up is advisable.

Diffusion-weighted MRI as an adjunct to mammography in women under 50 years of age: an initial study.

PURPOSE: To evaluate diffusion-weighted magnetic resonance (DW) imaging as an adjunct to mammography for the detection of small invasive breast cancer. MATERIALS AND METHODS: Institutional review board standards were followed for this retrospective study. We performed both breast DW imaging and mammography on 25 women under 50 years of age with pathologically proven T1 breast cancer and on 21 healthy women under 50 years of age. Four offsite radiologists blind to the clinical information independently interpreted the mammograms and DW images and then classified their confidence level regarding the presence of breast cancer. The composite area under receiver operating characteristic curve (AUC), of mammography alone, DW imaging alone, and the combination of DW imaging and mammography (DWI/Cal) were calculated. RESULTS: The AUC of composite ROC curves of mammography, DW imaging, DWI/Cal combination, was 0.79 (95% CI, 0.72-0.87), 0.86 (95% CI, 0.84-0.87), and 0.96 (95% CI, 0.92-1.00), respectively. CONCLUSION: DW imaging may be a useful adjunct to mammography in the detection of small invasive breast cancer in women under 50 years of age.

The incidence and significance of retropharyngeal lymph node metastases in hypopharyngeal cancer.

OBJECTIVE: To evaluate the incidence and clinical significance of retropharyngeal lymph node metastasis in hypopharyngeal cancer. METHODS: Pretreatment computed tomography and/or magnetic resonance images of 152 patients treated between 1998 and 2009 were retrospectively reviewed. The prognostic significance of retropharyngeal lymph node metastasis for 116 patients who received definitive treatment was also analyzed. RESULTS: Twelve patients (8%) were radiologically positive for retropharyngeal lymph node metastasis. Tumors originating from the posterior wall showed significantly higher incidence of retropharyngeal lymph node than those originating from other sites (23.8 vs. 5.3%, P = 0.01). The majority of patients with retropharyngeal lymph node involvement experienced distant metastasis. The overall survival rate of patients with retropharyngeal lymph node metastasis was worse than in those lacking retropharyngeal lymph node involvement (0 vs. 68.8% at 2 years, P < 0.01), and so was the cause-specific survival rate (0 vs. 74% at 2 years, P < 0.01). CONCLUSIONS: Patients with hypopharyngeal cancer, especially those with posterior wall tumors, are at high risk for retropharyngeal lymph node involvement. Patients with retropharyngeal lymph node metastasis developed distant metastasis frequently, and showed dismal outcomes.

A case of COVID-19 with the atypical CT finding.

COVID-19 usually demonstrates the specific pattern of chest CT findings (GGO, inverted-halo sign, etc). However, some COVID-19 cases show atypical CT findings. Physicians should make comprehensive judgments.

Chronic obstructive pulmonary disease and interstitial lung disease in patients with lung cancer.

BACKGROUND AND OBJECTIVE: Although lung cancer is frequently accompanied by COPD and interstitial lung disease (ILD), the precise coincidence of these diseases with lung cancer is not well understood. The objectives of this study were to determine the prevalence of abnormal CT and spirometric findings suggestive of COPD or ILD in a population of patients with untreated lung cancer, and to estimate the lung cancer risk in this population. METHODS: The study population consisted of 256 patients with untreated lung cancer and 947 subjects participating in a CT screening programme for lung cancer. Semi-quantitative analysis of low attenuation area (LAA), fibrosis and ground glass attenuation (GGA) on CT was performed by scoring. Gender- and age-matched subpopulations, with stratification by smoking status, were compared using the Mantel-Haenszel projection method. RESULTS: Inter-observer consistency was excellent for LAA, but not as good for fibrosis or GGA scores. Pooled odds ratios for lung cancer risk using LAA, fibrosis, GGA scores and reduced FEV(1)/FVC and %VC were 3.63, 5.10, 2.71, 7.17 and 4.73, respectively (P < 0.0001 for all parameters). Multivariate regression analyses confirmed these results. CONCLUSION: Abnormal CT and spirometric parameters suggestive of COPD and ILD were strong risk factors for lung cancer, even after adjusting for gender, age and smoking status.

Functional computed tomography imaging of tumor-induced angiogenesis: preliminary results of new tracer kinetic modeling using a computer discretization approach.

PURPOSE: The aim of this study was to establish functional computed tomography (CT) imaging as a method for assessing tumor-induced angiogenesis. MATERIALS AND METHODS: Functional CT imaging was mathematically analyzed for 14 renal cell carcinomas by means of two-compartment modeling using a computer-discretization approach. The model incorporated diffusible kinetics of contrast medium including leakage from the capillary to the extravascular compartment and back-flux to the capillary compartment. The correlations between functional CT parameters [relative blood volume (rbv), permeability 1 (Pm1), and permeability 2 (Pm2)] and histopathological markers of angiogenesis [microvessel density (MVD) and vascular endothelial growth factor (VEGF)] were statistically analyzed. RESULTS: The modeling was successfully performed, showing similarity between the mathematically simulated curve and the measured time-density curve. There were significant linear correlations between MVD grade and Pm1 (r = 0.841, P = 0.001) and between VEGF grade and Pm2 (r = 0.804, P = 0.005) by Pearson's correlation coefficient. CONCLUSION: This method may be a useful tool for the assessment of tumor-induced angiogenesis.

Comparison of endobronchial ultrasound, positron emission tomography, and CT for lymph node staging of lung cancer.

STUDY OBJECTIVES: To perform a prospective comparison of direct real-time endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA), positron emission tomography (PET), and thoracic CT for detection of mediastinal and hilar lymph node metastasis in patients with lung cancer considered for surgical resection. DESIGN: Prospective patient enrollment. SETTING: University teaching hospital. PATIENTS: One hundred two potentially operable patients with proven (n = 96) or radiologically suspected (n = 6) lung cancer were included in the study. INTERVENTIONS: CT, PET, and EBUS-TBNA were performed prior to surgery for the evaluation of mediastinal and hilar lymph node metastasis. The convex probe EBUS, which is integrated with a convex scanning probe on its tip, was used for EBUS-TBNA. Surgical histology was used as the "gold standard" to confirm lymph node metastasis unless patients were found inoperable for N3 or extensive N2 disease proven by EBUS-TBNA. MAIN RESULTS: EBUS-TBNA was successfully performed in all 102 patients (mean age, 67.8 years) from 147 mediastinal and 53 hilar lymph nodes. EBUS-TBNA proved malignancy in 37 lymph node stations in 24 patients. CT identified 92 positive lymph nodes, and PET identified 89 positive lymph nodes (4 supraclavicular, 63 mediastinal, 22 hilar). The sensitivities of CT, PET, and EBUS-TBNA for the correct diagnosis of mediastinal and hilar lymph node staging were 76.9%, 80.0%, and 92.3%, respectively; specificities were 55.3%, 70.1%, and 100%, and diagnostic accuracies were 60.8%, 72.5%, and 98.0%. EBUS-TBNA was uneventful, and there were no complications. CONCLUSION: Compared to CT and PET, EBUS-TBNA has a high sensitivity as well as specificity for mediastinal and hilar lymph node staging in patients with lung cancer. EBUS-TBNA should be considered for evaluation of the mediastinum early in the staging process of lung cancer.

Basal cell adenoma of the parotid gland; MR features and differentiation from pleomorphic adenoma.

OBJECTIVES: Among the benign tumours of the parotid gland, basal cell adenoma (BCA) is far less common than pleomorphic adenoma (PA). MR features of BCA, including diffusion-weighted imaging and dynamic contrast-enhanced study, have not been previously described. Assessment of the crucial MR features of BCA appears to offer beneficial clues for distinguishing BCA from PA. METHODS: We retrospectively reviewed 14 BCAs and 179 PAs in the parotid gland, collected between March 2000 and May 2012, from the MRI database. RESULTS: Nearly half of the BCAs had cystic components. The average ratio of the maximum diameter of the cysts to the BCAs (cystic ratio) was 0.80 ± 0.11 [standard deviation (SD)]. The BCA cystic ratio was significantly higher (p = 0.00232) than that of PAs. The cystic ratio threshold was 0.65 between cystic BCA and cystic PA. Sensitivity and specificity were 76.5% and 100%, respectively. The average of the apparent diffusion coefficient (ADC) values of the 12 BCAs [1.24 ± 0.18 (SD) ×10(-3) mm(2) s(-1)] was significantly lower than that of the 151 PAs [1.86 ± 0.40 (SD) ×10(-3) mm(2) s(-1)] (p < 0.001) and also lower than that of the cystic PAs [1.83 ± 0.57 (SD) ×10(-3) mm(2) s(-1)] (p < 0.00495). The ADC threshold was 1.31 × 10(-3) mm(2) s(-1) between BCA and cystic PA, with sensitivity and specificity of 81.2% and 91.7%, respectively, and also the same threshold 1.31 × 10(-3) mm(2) s(-1) between BCA and PA, with sensitivity and specificity of 92.7% and 91.7%, respectively. Time-signal intensity curves (TICs) showed various patterns. CONCLUSIONS: A small cystic mass with well-circumscribed borders and slightly lower ADC value may suggest BCA, although TICs showed various patterns.

MR imaging of salivary duct carcinoma.

BACKGROUND AND PURPOSE: Salivary duct carcinoma (SDC) is regarded as a high-grade malignancy in the current classification of salivary gland neoplasms. The aim of our study was to describe the MR imaging features of SDC. METHODS: Nine patients with SDC underwent MR imaging study. The apparent diffusion coefficient (ADC) values of SDCs were measured from diffusion-weighted images. Time-signal intensity curves (TICs) of the tumors on dynamic MR images were plotted, and washout ratios were also calculated. TICs were divided into four types: type A, curve peaks <120 seconds after administration of contrast material with high washout ratio (> or =30%); type B, curve peaks <120 seconds with low washout ratio (<30%); type C, curve peaks >120 seconds; type D, nonenhanced. We correlated the MR findings of SDC with the pathologic findings. RESULTS: All tumors had ill-defined margins and showed low to moderately high signal intensity for contralateral parotid gland on T2-weighted images. The average of the ADC values of the SDCs was 1.16 +/- 0.14 [SD] x 10(-3)mm(2)/s. Seven of nine (78%) tumors had type B enhancement. On the other hand, six of nine (67%) tumors with rich fibrotic tissue also had type C enhancement. CONCLUSION: The findings of ill-defined margin, early enhancement with low washout ratio (type B), and low ADC value (1.22 x 10(-3)mm(2)/s) were useful for suggesting malignant salivary gland tumors. Although it was reported that type C enhancement was specific for pleomorphic adenoma, SDC frequently has type C-enhanced focus.

Diagnostic value of FDG PET and salivary gland scintigraphy for parotid tumors.

PURPOSE: The purpose of this study was to examine the diagnostic value of the combination of F-18 fluorodeoxyglucose (FDG) PET and Tc-99m pertechnetate salivary gland scintigraphy in parotid tumors. MATERIALS AND METHODS: Seventy-two patients with benign parotid gland tumors (n = 52), malignant parotid tumors (n = 12), and inflammation (n = 8) underwent both FDG PET and salivary gland scintigraphy within 1 week, and 66 of the patients also underwent gallium scintigraphy. All patients were negative on their first fine-needle aspiration (FNA). RESULTS: Malignant parotid tumors showed significantly higher FDG uptake (standard uptake values [SUVs]) than both benign tumors and inflammation, except in Warthin's tumor (5.82 +/- 3.95 vs. 2.07 +/- 1.33; P <0.01). Although the SUV values of Warthin's tumor and malignant parotid tumors overlapped somewhat, Warthin's tumor did demonstrate increased radiotracer uptake, and it was reliably distinguished from other parotid gland tumors by the use of salivary gland scintigraphy. Considering a SUV value >3 as being positive for malignancy and excluding Warthin's tumor on the basis of salivary gland scintigraphy, sensitivity and specificity of FDG PET were 75% and 80%, respectively. These results were superior to those of gallium scintigraphy (58% and 72%, respectively). CONCLUSIONS: Although the diagnostic value of FDG PET in the differentiation of malignant from benign parotid gland tumors was limited because of the high FDG uptake in some benign tumors, and particularly pleomorphic adenomas, combining salivary gland scintigraphy with FDG PET may help to negate this drawback, and this combination may be a more promising approach for differentiation of various parotid gland tumors in patients compared with nondiagnostic needle aspiration.

Warthin tumor of the parotid gland: diagnostic value of MR imaging with histopathologic correlation.

BACKGROUND AND PURPOSE: The purpose of our study was to describe the MR imaging appearance of Warthin tumors multiple MR imaging techniques and to interpret the difference in appearance from that of malignant parotid tumors. METHODS: T1-weighted, T2-weighted, short inversion time inversion recovery, diffusion-weighted, and contrast-enhanced dynamic MR images of 19 Warthin tumors and 17 malignant parotid tumors were reviewed. MR imaging results were compared with those of pathologic analysis. RESULTS: Epithelial stromata and lymphoid tissue with slitlike small cysts in Warthin tumors showed early enhancement and a high washout rate (> or =30%) on dynamic contrast-enhanced images, and accumulations of complicated cysts showed early enhancement and a low washout ratio (< 30%). The areas containing complicated cysts showed high signal intensity on T1-weighted images, whereas some foci in those areas showed low signal intensity on short tau inversion recovery images. The mean minimum signal intensity ratios (SIRmin) of Warthin tumor on short tau inversion recovery (0.29 +/- 0.22 SD) (P < .01) and T2-weighted images (0.28 +/- 0.09) (P < .05) were significantly lower than those of malignant parotid tumors (0.53 +/- 0.19, 0.48 +/- 0.19). The average washout ratio of Warthin tumors (44.0 +/- 20.4%) was higher than that of malignant parotid tumors (11.9 +/- 11.6%). The mean apparent diffusion coefficient of Warthin tumors (0.96 +/- 0.13 x 10(-3)mm2/s) was significantly lower (P < .01) than that of malignant tumors (1.19 +/- 0.19 x 10(-3)mm2/s). CONCLUSION: Detecting hypointense areas of short tau inversion recovery and T2-weighted images or low apparent diffusion coefficient values on diffusion-weighted images was useful for predicting whether salivary gland tumors were Warthin tumors. The findings of the dynamic contrast-enhanced study also were useful.

Induction of chromatin damage and distribution of isochromatid breaks in human fibroblast cells exposed to heavy ions.

The frequency of chromatid breaks and the distribution of isochromatid breaks were measured in G2-phase normal human fibroblasts prematurely condensed a short time after exposure to low- or high-LET radiations. The average number of isochromatid breaks from a single particle traversal increased with increasing LET values, while the average number of chromatid-type breaks appeared to reach a plateau. The distribution of isochromatid breaks after high-LET iron particles exposure was overdispersed compared to gamma-rays, indicating that a single iron particle traversal through a cell nucleus can produce multiple isochromatid breaks.

Diffuse pulmonary involvement by mycosis fungoides: high-resolution computed tomography and pathologic findings.

The authors report the high-resolution computed tomography (HRCT) appearance of diffuse pulmonary involvement by mycosis fungoides in a 74-year-old woman whose clinical and radiographic manifestations simulated pneumonia. The HRCT showed multiple, dense, peribronchovascular nodules with surrounding ground-glass opacity and several wedge-shape peripheral opacities. The autopsy specimen revealed angiocentric and peribronchovascular involvement of mycosis fungoides and pulmonary infarctions distal to angiocentric infiltration of the tumor cells.

Fat suppression strategies in MR imaging of breast cancer at 3.0 T: comparison of the two-point Dixon technique and the frequency selective inversion method.

PURPOSE: To compare two fat suppression methods in contrast-enhanced MR imaging of breast cancer at 3.0 T: the two-point Dixon method and the frequency selective inversion method. MATERIALS AND METHODS: Forty female patients with breast cancer underwent contrast-enhanced three-dimensional T1-weighted MR imaging at 3.0 T. Both the two-point Dixon method and the frequency selective inversion method were applied. Quantitative analyses of the residual fat signal-to-noise ratio and the contrast noise ratio (CNR) of lesion-to-breast parenchyma, lesion-to-fat, and parenchyma-to-fat were performed. Qualitative analyses of the uniformity of fat suppression, image contrast, and the visibility of breast lesions and axillary metastatic adenopathy were performed. RESULTS: The signal-to-noise ratio was significantly lower in the two-point Dixon method (P < 0.001). All CNR values were significantly higher in the two-point Dixon method (P < 0.001 and P = 0.001, respectively). According to qualitative analysis, both the uniformity of fat suppression and image contrast with the two-point Dixon method were significantly higher (P < 0.001 and P = 0.002, respectively). Visibility of breast lesions and metastatic adenopathy was significantly better in the two-point Dixon method (P < 0.001 and P = 0.03, respectively). CONCLUSION: The two-point Dixon method suppressed the fat signal more potently and improved contrast and visibility of the breast lesions and axillary adenopathy.

Detection of adrenal veins on selective retrograde CT adrenal venography in comparison with digital subtraction angiography in subjects with established diagnosis of one-sided adrenal aldosterone-producing tumor confirmed by adrenal vein sampling, histopathology and clinical course.

PURPOSE: Adrenal vein (AV) sampling (AVS) is the diagnostic gold standard for primary aldosteronism (PA), but right-sided AVS is difficult. We compared detection of AVs by selective retrograde CT adrenal venography (SRCTAV) with digital subtraction angiography (DSA). MATERIALS AND METHODS: Data on 29 subjects (11 males, mean age 55 y) with increased serum aldosterone concentrations (SAC) and a diagnosed right or left aldosterone-producing tumor (APT) by AVS who underwent laparoscopic adrenalectomy were retrospectively analyzed. Before AVS, visualizing AVs was attempted by DSA and SRCTAV (Aquilion). If after the adrenocorticotropic hormone loading test serum cortisol concentration (SCC) from either AV was >200 µg/dl, AVS was considered successful. If the SAC/SCC ratio for one side was ≥4 times higher than the other side, we diagnosed a one-sided APT. RESULTS: Left and right AV, respectively, were visualized in 29 (100%) and 22 subjects (76%) by DSA and 29 (100%) and 28 subjects (97%) by SRCTAV, with right-AV detection significantly higher by SRCTAV (p<0.05). Cannulations were regarded successful in 28 subjects having both AVs observed on SRCTAV but not in the remaining subject whose adrenocortical scintigram was positive, however. Adrenalectomy was performed with a diagnosis of adenoma. Among 28 subjects with successful AVS, histopathological diagnoses included adenoma (25), nodular hyperplasia (2) and normal (1). After adrenalectomy, antihypertensive drug usage in 28 patients was reduced or stopped with decreases in SAC (97%). CONCLUSIONS: Detection of AV was significantly higher by SRCTAV than DSA, especially on the right side, in 29 subjects diagnosed with one-sided APT.

A pictorial review of benign hepatocellular nodular lesions: comprehensive radiological assessment incorporating the concept of anomalous portal tract syndrome.

BACKGROUND/PURPOSE: Although the pathological categorization system advocated by the International Working Party (IWP) on Terminology has been helpful in categorizing benign hepatocellular lesions, the diverse clinicopathological features of the lesions still cause confusion of diagnosis in clinical settings. Recently, an integrated disease concept termed "anomalous portal tract syndrome" (APTS) has been proposed as a congenital anomaly of the portal tract, being a single unifying etiological factor underlying the disorder. In this article, we discuss the radiological features of benign nodular hepatocellular lesions incorporated in the concept of APTS. METHODS: We systematically reviewed the literature on benign hepatocellular lesions based on the concept of APTS, as well as standard IWP terminology. For this pictorial review, we selected six representative cases and assessed the radiological features of the cases based on the concept of APTS. RESULTS: The comprehensive assessment based on APTS enabled the systematic categorization of benign hepatocellular lesions, including nodular regenerative hyperplasia, large regenerative nodules, partial nodular transformation, focal nodular hyperplasia, and hepatocellular adenoma, and was helpful in understanding the overlapping features of these lesions. CONCLUSIONS: Although the disease concept of APTS is still evolving, it is nonetheless helpful in comprehensively understanding the clinicopathological and radiological features of various benign hepatocellular lesions.

Dual-time point scanning of integrated FDG PET/CT for the evaluation of mediastinal and hilar lymph nodes in non-small cell lung cancer diagnosed as operable by contrast-enhanced CT.

PURPOSE: To evaluate whether dual-time point scanning with integrated fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography and computed tomography (PET/CT) is useful for evaluation of mediastinal and hilar lymph nodes in non-small cell lung cancer diagnosed as operable by contrast-enhanced CT. MATERIALS AND METHODS: PET/CT data and pathological findings of 560 nodal stations in 129 patients with pathologically proven non-small cell lung cancer diagnosed as operable by contrast-enhanced CT were reviewed retrospectively. Standardized uptake values (SUVs) on early scans (SUVe) 1h, and on delayed scans (SUVd) 2h after FDG injection of each nodal station were measured. Retention index (RI) (%) was calculated by subtracting SUVe from SUVd and dividing by SUVe. Logistic regression analysis was performed with seven kinds of models, consisting of (1) SUVe, (2) SUVd, (3) RI, (4) SUVe and SUVd, (5) SUVe and RI, (6) SUVd and RI, and (7) SUVe, SUVd and RI. The seven derived models were compared by receiver-operating characteristic (ROC) analysis. k-Fold cross-validation was performed with k values of 5 and 10. p<0.05 was considered statistically significant. RESULTS: Model (1) including the term of SUVe showed the largest area under the ROC curve among the seven models. The cut-off probability of metastasis of 3.5% with SUVe of 2.5 revealed a sensitivity of 78% and a specificity of 81% on ROC analysis, and approximately 60% and 80% on k-fold cross-validation. CONCLUSION: Single scanning of PET/CT is sufficiently useful for evaluating mediastinal and hilar nodes for metastasis.