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Background Pulmonary MRI with ultrashort echo time (UTE) has been compared with chest CT for nodule detection and classification. However, direct comparisons of these methods' capabilities for Lung CT Screening Reporting and Data System (Lung-RADS) evaluation remain lacking. Purpose To compare the capabilities of pulmonary MRI with UTE with those of standard- or low-dose thin-section CT for Lung-RADS classification. Materials and Methods In this prospective study, standard- and low-dose chest CT (270 mA and 60 mA, respectively) and MRI with UTE were used to examine consecutive participants enrolled between January 2017 and December 2020 who met American College of Radiology Appropriateness Criteria for lung cancer screening with low-dose CT. Probability of nodule presence was assessed for all methods with a five-point visual scoring system by two board-certified radiologists. All nodules were then evaluated in terms of their Lung-RADS classification using each method. To compare nodule detection capability of the three methods, consensus for performances was rated by using jackknife free-response receiver operating characteristic analysis, and sensitivity was compared by means of the McNemar test. In addition, weighted κ statistics were used to determine the agreement between Lung-RADS classification obtained with each method and the reference standard generated from standard-dose CT evaluated by two radiologists who were not included in the image analysis session. Results A total of 205 participants (mean age: 64 years ± 7 [standard deviation], 106 men) with 1073 nodules were enrolled. Figure of merit (FOM) (

Background Deep learning may help to improve computer-aided detection of volume (CADv) measurement of pulmonary nodules at chest CT. Purpose To determine the efficacy of a deep learning method for improving CADv for measuring the solid and ground-glass opacity (GGO) volumes of a nodule, doubling time (DT), and the change in volume at chest CT. Materials and Methods From January 2014 to December 2016, patients with pulmonary nodules at CT were retrospectively reviewed. CADv without and with a convolutional neural network (CNN) automatically determined total nodule volume change per day and DT. Area under the curves (AUCs) on a per-nodule basis and diagnostic accuracy on a per-patient basis were compared among all indexes from CADv with and without CNN for differentiating benign from malignant nodules. Results The CNN training set was 294 nodules in 217 patients, the validation set was 41 nodules in 32 validation patients, and the test set was 290 nodules in 188 patients. A total of 170 patients had 290 nodules (mean size ± standard deviation, 11 mm ± 5; range, 4-29 mm) diagnosed as 132 malignant nodules and 158 benign nodules. There were 132 solid nodules (46%), 106 part-solid nodules (36%), and 52 ground-glass nodules (18%). The test set results showed that the diagnostic performance of the CNN with CADv for total nodule volume change per day was larger than DT of CADv with CNN (AUC, 0.94 [95% confidence interval {CI}: 0.90, 0.96] vs 0.67 [95% CI: 0.60, 0.74]; P < .001) and CADv without CNN (total nodule volume change per day: AUC, 0.69 [95% CI: 0.62, 0.75]; P < .001; DT: AUC, 0.58 [95% CI: 0.51, 0.65]; P < .001). The accuracy of total nodule volume change per day of CADv with CNN was significantly higher than that of CADv without CNN (P < .001) and DT of both methods (P < .001). Conclusion Convolutional neural network is useful for improving accuracy of computer-aided detection of volume measurement and nodule differentiation capability at CT for patients with pulmonary nodules. © RSNA, 2020 Online supplemental material is available for this article.

Purpose To compare the capability of pulmonary thin-section magnetic resonance (MR) imaging with ultrashort echo time (UTE) with that of standard- and reduced-dose thin-section computed tomography (CT) in nodule detection and evaluation of nodule type. Materials and Methods The institutional review board approved this study, and written informed consent was obtained from each patient. Standard- and reduced-dose chest CT (60 and 250 mA) and MR imaging with UTE were used to examine 52 patients; 29 were men (mean age, 66.4 years ± 7.3 [standard deviation]; age range, 48-79 years) and 23 were women (mean age, 64.8 years ± 10.1; age range, 42-83 years). Probability of nodule presence was assessed for all methods with a five-point visual scoring system. All nodules were then classified as missed, ground-glass, part-solid, or solid nodules. To compare nodule detection capability of the three methods, consensus for performances was rated by using jackknife free-response receiver operating characteristic analysis, and κ analysis was used to compare intermethod agreement for nodule type classification. Results There was no significant difference (F = 0.70, P = .59) in figure of merit between methods (standard-dose CT, 0.86; reduced-dose CT, 0.84; MR imaging with UTE, 0.86). There was no significant difference in sensitivity between methods (standard-dose CT vs reduced-dose CT, P = .50; standard-dose CT vs MR imaging with UTE, P = .50; reduced-dose CT vs MR imaging with UTE, P >.99). Intermethod agreement was excellent (standard-dose CT vs reduced-dose CT, κ = 0.98, P < .001; standard-dose CT vs MR imaging with UTE, κ = 0.98, P < .001; reduced-dose CT vs MR imaging with UTE, κ = 0.99, P < .001). Conclusion Pulmonary thin-section MR imaging with UTE was useful in nodule detection and evaluation of nodule type, and it is considered at least as efficacious as standard- or reduced-dose thin-section CT. © RSNA, 2017 Online supplemental material is available for this article.

To prospectively evaluate the capability of amide proton transfer-weighted chemical exchange saturation transfer magnetic resonance (MR) imaging for characterization of thoracic lesions.The institutional review board approved this study, and written informed consent was obtained from 21 patients (13 men and eight women; mean age, 72 years) prior to enrollment. Each patient underwent chemical exchange saturation transfer MR imaging by using respiratory-synchronized half-Fourier fast spin-echo imaging after a series of magnetization transfer pulses. Next, a magnetization transfer ratio asymmetry at 3.5 ppm map was computationally generated. Pathology examinations resulted in a diagnosis of 13 malignant and eight benign thoracic lesions. The malignant lesions were further diagnosed as being nine lung cancers, comprising six adenocarcinomas, three squamous cell carcinomas, and four other thoracic malignancies. The Student t test was used to evaluate the capability of magnetization transfer ratio asymmetry (at 3.5 ppm), as assessed by means of region of interest measurements, for differentiating benign and malignant lesions, lung cancers and other thoracic lesions, and adenocarcinomas and squamous cell carcinomas.Magnetization transfer ratio asymmetry (at 3.5 ppm) was significantly higher for malignant tumors (mean ± standard deviation, 3.56% ± 3.01) than for benign lesions (0.33% ± 0.38, P = .008). It was also significantly higher for other thoracic malignancies (6.71% ± 3.46) than for lung cancer (2.16% ± 1.41, P = .005) and for adenocarcinoma (2.88% ± 1.13) than for squamous cell carcinoma (0.71% ± 0.17, P = .02).Amide proton transfer-weighted chemical exchange saturation transfer MR imaging allows characterization of thoracic lesions.

To prospectively compare the capabilities for TNM classification and assessment of clinical stage and operability among whole-body magnetic resonance (MR) imaging, coregistered positron emission tomographic (PET)/MR imaging with and without MR signal intensity (SI) assessment, and integrated fluorine 18 fluorodeoxyglucose (FDG) PET/computed tomography (CT) in non-small cell lung cancer (NSCLC) patients.The institutional review board approved this study, and written informed consent was obtained from each patient. One hundred forty consecutive NSCLC patients (75 men, 65 women; mean age, 72 years) prospectively underwent whole-body MR imaging, FDG PET/CT, conventional radiologic examinations, and surgical, pathologic, and/or follow-up examinations. All factors and clinical stage and operability were then visually assessed. All PET/MR examinations were assessed with and without SI assessment. One examination used anatomic, metabolic, and relaxation-time information, and the other used only anatomic and metabolic information. κ statistics were used for assessment of all factors and clinical stages with final diagnoses. McNemar test was used to compare the capability of all methods to assess operability.Agreements of assessment of every factor (κ = 0.63-0.97) and clinical stage (κ = 0.65-0.90) were substantial or almost perfect. Regarding capability to assess operability, accuracy of whole-body MR imaging and PET/MR imaging with SI assessment (97.1% [136 of 140]) was significantly higher than that of MR/PET without SI assessment and integrated FDG PET/CT (85.0% [119 of 140]; P.001).Accuracies of whole-body MR imaging and PET/MR imaging with SI assessment are superior to PET/MR without SI assessment and PET/CT for identification of TNM factor, clinical stage, and operability evaluation of NSCLC patients.

To compare the use of dynamic oxygen-enhanced magnetic resonance (MR) imaging with the use of quantitatively assessed computed tomography (CT) for assessment of clinical stage and evaluation of pulmonary functional change due to treatment in patients with asthma.The institutional review board of Kobe University Hospital approved this study, and written informed consent was obtained from each subject. Thirty consecutive patients with asthma (17 men and 13 women; age range, 27-78 years) underwent dynamic oxygen-enhanced MR imaging, multidetector CT, and assessment of forced expiratory volume in 1 second. All patients were classified as having one of four stages of asthma according to the guidelines of the National Asthma Education and Prevention Program. Relative enhancement ratio ( RER relative enhancement ratio ) and wash-in time maps were generated by means of pixel-by-pixel analyses. Regions of interest were placed on images of the lung in all sections, and all measurements were averaged to determine mean RER relative enhancement ratio and mean wash-in time for each subject. Percentage of airway wall area and mean lung density were determined at quantitative CT. For comparison of the modalities for assessment of clinical stage, indexes of subjects at all clinical stages were compared by means of the Tukey honestly significant difference test. Evaluation of pulmonary functional improvement was assessed by correlating improvement of each index with that of forced expiratory volume.Mean wash-in time was significantly different among patients with asthma of different clinical stages (P.05), but significant differences between mean RER relative enhancement ratio and percentage of airway wall area were observed for a limited number of clinical stages (P.05). Improvement of mean RER relative enhancement ratio (r = 0.63, P = .0002) and mean wash-in time (r = -0.75, P.0001) was significantly correlated with forced expiratory volume.Dynamic oxygen-enhanced MR imaging has potential as a tool for assessment of clinical stage and evaluation of pulmonary functional change due to treatment in patients with asthma.

To prospectively compare the capabilities of dynamic perfusion area-detector computed tomography (CT), dynamic magnetic resonance (MR) imaging, and positron emission tomography (PET) combined with CT (PET/CT) with use of fluorine 18 fluorodeoxyglucose (FDG) for the diagnosis of solitary pulmonary nodules.The institutional review board approved this study, and written informed consent was obtained from each subject. A total of 198 consecutive patients with 218 nodules prospectively underwent dynamic perfusion area-detector CT, dynamic MR imaging, FDG PET/CT, and microbacterial and/or pathologic examinations. Nodules were classified into three groups: malignant nodules (n = 133) and benign nodules with low (n = 53) or high (n = 32) biologic activity. Total perfusion was determined with dual-input maximum slope models at area-detector CT, maximum and slope of enhancement ratio at MR imaging, and maximum standardized uptake value (SUVmax) at PET/CT. Next, all indexes for malignant and benign nodules were compared with the Tukey honest significant difference test. Then, receiver operating characteristic analysis was performed for each index. Finally, sensitivity, specificity, and accuracy were compared with the McNemar test.All indexes showed significant differences between malignant nodules and benign nodules with low biologic activity (P.0001). The area under the receiver operating characteristic curve for total perfusion was significantly larger than that for other indexes (.0006 ≤ P ≤ .04). The specificity and accuracy of total perfusion were significantly higher than those of maximum relative enhancement ratio (specificity, P.0001; accuracy, P.0001), slope of enhancement ratio (specificity, P.0001; accuracy, P.0001), and SUVmax (specificity, P.0001; accuracy, P.0001).Dynamic perfusion area-detector CT is more specific and accurate than dynamic MR imaging and FDG PET/CT in the diagnosis of solitary pulmonary nodules in routine clinical practice.

To prospectively compare the diagnostic capability of short inversion time inversion-recovery (STIR) turbo spin-echo (SE) imaging, diffusion-weighted (DW) magnetic resonance (MR) imaging, and fluorodeoxyglucose (FDG) combined positron emission tomography (PET) and computed tomography (CT) in N stage assessment in patients with non-small cell lung cancer (NSCLC).This prospective study was approved by the institutional review board, and written informed consent was obtained from all patients. A total of 250 consecutive patients with NSCLC (136 men; mean age, 73 years; 114 women; mean age, 72 years) prospectively underwent pretherapeutic STIR turbo SE imaging, DW MR imaging, and FDG PET/CT, as well as surgical and pathologic examinations (N0 disease, n = 157; N1 disease, n = 72; N2 disease, n = 16; N3 disease, n = 5). Lymph node-to-saline ratio (LSR), lymph node-to-muscle ratio (LMR), apparent diffusion coefficient (ADC), maximal standardized uptake value (SUV(max)), and visual scoring were assessed for 135 metastatic lymph nodes and 135 randomly selected nonmetastatic lymph nodes. Receiver operating characteristic curve analysis was used to determine feasible threshold values. Diagnostic capabilities for N stage assessment were compared with the McNemar test on a per-patient basis.When feasible, threshold values were used for quantitative assessment; sensitivity and accuracy of LSR and LMR (sensitivity, 82.8%; accuracy, 86.8%) proved to be significantly higher than those of ADC (sensitivity: 74.2%, P = .01; accuracy: 84.4%, P = .04) and SUV(max) (sensitivity: 74.2%, P = .01). For qualitative assessment, sensitivity of STIR turbo SE imaging (77.4%) was significantly higher than that of DW MR imaging (71.0%, P = .03) and FDG PET/CT (69.9%, P = .02).Quantitative and qualitative assessments of N stage disease in patients with NSCLC obtained with STIR turbo SE MR imaging are more sensitive and/or more accurate than those obtained with DW MR imaging and FDG PET/CT.http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110281/-/DC1.

To prospectively compare the capability of quantitative first-pass perfusion 320-detector row computed tomography (CT) (ie, area-detector CT) with that of combined positron emission tomography and CT (PET/CT) for differentiation between malignant and benign pulmonary nodules.This prospective study was approved by the institutional review board, and written informed consent was obtained from 50 consecutive patients with 76 pulmonary nodules. All patients underwent dynamic area-detector CT, PET/CT, and microbacterial and/or histopathologic examinations. All pulmonary nodules were divided into three groups: malignant nodules (n = 43), benign nodules with low biologic activity (n = 6), and benign nodules with high biologic activity (n = 27). For each dynamic area-detector CT data set, the perfusion derived by using the maximum slope model (PF(MS)), extraction fraction derived by using the Patlak plot model (EF(PP)), and blood volume derived by using the Patlak plot model (BV(PP)) were calculated. These parameters were statistically compared among the three nodule groups. Receiver operating characteristic (ROC) analyses were used to compare the diagnostic capability of the CT and PET/CT indexes. Finally, the sensitivity, specificity, and accuracy of each index were compared by using the McNemar test.All indexes in the malignant nodule group were significantly different from those in the low-biologic-activity benign nodule group (P.05). Areas under the ROC curve for PF(MS) and EF(PP) were significantly larger than those for BV(PP) (P.05) and maximal standard uptake value (SUV(max)) (P.05). The specificity and accuracy of PF(MS) and EF(PP) were significantly higher than those of BV(PP) and SUV(max) (P.05).Dynamic first-pass area-detector perfusion CT has the potential to be more specific and accurate than PET/CT for differentiating malignant from benign pulmonary nodules.http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100245/-/DC1.

To prospectively and directly compare the capability of whole-body diffusion-weighted (DW) imaging, whole-body magnetic resonance (MR) imaging with and that without DW imaging, and integrated fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for M-stage assessment in non-small cell lung cancer (NSCLC) patients.The institutional review board approved this study; informed consent was obtained from patients. A total of 203 NSCLC patients (109 men, 94 women; mean age, 72 years) prospectively underwent whole-body DW imaging, whole-body MR imaging, and FDG PET/CT. Final diagnosis of the M-stage in each patient was determined on the basis of results of all radiologic and follow-up examinations. Two chest radiologists and two nuclear medicine physicians independently assessed all examination results and used a five-point visual scoring system to evaluate the probability of metastases. Final diagnosis based on each of the methods was made by consensus of two readers. Receiver operating characteristic (ROC) analysis was used to compare the capability for M-stage assessment among whole-body DW imaging, whole-body MR imaging with and that without DW imaging, and PET/CT on a per-patient basis. Sensitivity, specificity, and accuracy were compared with the McNemar test.Area under ROC curve (A(z)) values of whole-body MR imaging with DW imaging (A(z) = 0.87, P = .04) and integrated FDG PET/CT (A(z) = 0.89, P = .02) were significantly larger than that of whole-body DW imaging (A(z) = 0.79). Specificity and accuracy of whole-body MR imaging with (specificity, P = .02; accuracy, P.01) and that without DW imaging (specificity, P = .02; accuracy, P = .01) and integrated FDG PET/CT (specificity, P.01; accuracy, P.01) were significantly higher than those of whole-body DW imaging.Whole-body MR imaging with DW imaging can be used for M-stage assessment in NSCLC patients with accuracy as good as that of PET/CT.