Daisuke Takenaka

High Signal Intensity in the Dentate Nucleus and Globus Pallidus on Unenhanced T1-weighted MR Images: Relationship with Increasing Cumulative Dose of a Gadolinium-based Contrast Material

PURPOSE To explore any correlation between the number of previous gadolinium-based contrast material administrations and high signal intensity (SI) in the dentate nucleus and globus pallidus on unenhanced T1-weighted magnetic resonance (MR) images. MATERIALS AND METHODS The institutional review board approved this study, waiving the requirement to obtain written informed consent. A group of 381 consecutive patients who had undergone brain MR imaging was identified for cross-sectional analysis. For longitudinal analysis, 19 patients who had undergone at least six contrast-enhanced examinations were compared with 16 patients who had undergone at least six unenhanced examinations. The mean SIs of the dentate nucleus, pons, globus pallidus, and thalamus were measured on unenhanced T1-weighted images. The dentate nucleus-to-pons SI ratio was calculated by dividing the SI in the dentate nucleus by that in the pons, and the globus pallidus-to-thalamus SI ratio was calculated by dividing the SI in the globus pallidus by that in the thalamus. Stepwise regression analysis was undertaken in the consecutive patient group to detect any relationship between the dentate nucleus-to-pons or globus pallidus-to-thalamus SI ratio and previous gadolinium-based contrast material administration or other factors. A random coefficient model was used to evaluate for longitudinal analysis. RESULTS The dentate nucleus-to-pons SI ratio showed a significant correlation with the number of previous gadolinium-based contrast material administrations (P < .001; regression coefficient, 0.010; 95% confidence interval [CI]: 0.009, 0.011; standardized regression coefficient, 0.695). The globus pallidus-to-thalamus SI ratio showed a significant correlation with the number of previous gadolinium-based contrast material administrations (P < .001; regression coefficient, 0.004; 95% CI: 0.002, 0.006; standardized regression coefficient, 0.288), radiation therapy (P = .009; regression coefficient, -0.014; 95% CI: -0.025, -0.004; standardized regression coefficient, -0.151), and liver function (P = .031; regression coefficient, 0.023; 95% CI: 0.002, 0.044; standardized regression coefficient, 0.107). The dentate nucleus-to-pons and globus pallidus-to-thalamus SI ratios in patients who had undergone contrast-enhanced examinations were significantly greater than those of patients who had undergone unenhanced examinations (P < .001 for both). CONCLUSION High SI in the dentate nucleus and globus pallidus on unenhanced T1-weighted images may be a consequence of the number of previous gadolinium-based contrast material administrations.

Non–Small Cell Lung Cancer: Whole-Body MR Examination for M-Stage Assessment—Utility for Whole-Body Diffusion-weighted Imaging Compared with Integrated FDG PET/CT

PURPOSE 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. MATERIALS AND METHODS 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. RESULTS 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. CONCLUSION 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.

Quantitative assessment of regional pulmonary perfusion in the entire lung using three-dimensional ultrafast dynamic contrast-enhanced magnetic resonance imaging: Preliminary experience in 40 subjects.

To assess regional differences in quantitative pulmonary perfusion parameters, i.e., pulmonary blood flow (PBF), mean transit time (MTT), and pulmonary blood volume (PBV) in the entire lung on a pixel‐by‐pixel basis in normal volunteers and pulmonary hypertension patients.

Detection of bone metastases in non-small cell lung cancer patients: comparison of whole-body diffusion-weighted imaging (DWI), whole-body MR imaging without and with DWI, whole-body FDG-PET/CT, and bone scintigraphy.

To prospectively compare the capability for bone metastasis assessment of whole‐body diffusion‐weighted imaging (DWI), magnetic resonance imaging (MRI) without and with DWI, [18F] fluoro‐2‐D‐glucose positron emission tomography with computed tomography (FDG‐PET/CT) and bone scintigraphy in non‐small cell carcinoma (NSCLC) patients.

Dynamic oxygen-enhanced MRI reflects diffusing capacity of the lung

The purpose of this study was to demonstrate the feasibility of dynamic oxygen‐enhanced MRI in a clinical setting. We hypothesized that dynamic oxygen enhancement can reflect the regional diffusing capacity of the lung. Ten patients with pulmonary emphysema and seven healthy volunteers were examined with a respiratory‐synchronized inversion recovery single‐shot turbo spin‐echo sequence (TR = 3200–5000 ms, TE = 16 ms, TI = 720 ms, ETS = 4 ms) following 100% oxygen inhalation, using a 1.5 T whole‐body scanner. Maximum mean relative enhancement ratios calculated by averaging six defined regions of interest (ROIs) in both lungs were statistically compared between healthy volunteers and patients, and were correlated with diffusing lung capacity (%DLCO). In patients with pulmonary emphysema, maximum mean relative enhancement ratios were significantly decreased compared to those in healthy volunteers (P = 0.0008). Maximum mean relative enhancement ratio had excellent correlation with % DLC0 (r2 = 0.83). Dynamic oxygen‐enhanced MRI may reflect the diffusing capacity of the lung; therefore, imaging of oxygen enhancement with MRI may provide maps of the diffusing capacity. Magn Reson Med 47:1139–1144, 2002.

Differentiation of Malignant and Benign Pulmonary Nodules with Quantitative First-Pass 320–Detector Row Perfusion CT versus FDG PET/CT

PURPOSE 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. MATERIALS AND METHODS 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. RESULTS 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). CONCLUSION 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. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100245/-/DC1.

N stage disease in patients with non-small cell lung cancer: efficacy of quantitative and qualitative assessment with STIR turbo spin-echo imaging, diffusion-weighted MR imaging, and fluorodeoxyglucose PET/CT.

PURPOSE 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). MATERIALS AND METHODS 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. RESULTS 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). CONCLUSION 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. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110281/-/DC1.

Whole-body MR imaging vs. FDG-PET: Comparison of accuracy of M-stage diagnosis for lung cancer patients†

To conduct a prospective comparison of the accuracy of whole‐body MR imaging and positron emission tomography (PET) with fluorine‐18 deoxyglucose (FDG) (FDG‐PET) to assess the M‐stage in lung cancer patients.

Postoperative Lung Function in Lung Cancer Patients: Comparative Analysis of Predictive Capability of MRI, CT, and SPECT

OBJECTIVE The purpose of this study was to prospectively compare the utility of dynamic contrast-enhanced perfusion MRI in the prediction of postoperative lung function in patients with lung cancer with the utility of quantitative and qualitative assessment of CT and perfusion SPECT. SUBJECTS AND METHODS One hundred fifty lung cancer patients (87 men, 63 women) underwent dynamic perfusion MRI, MDCT, perfusion SPECT, and measurement of preoperative and postoperative forced expiratory volume in the first second of expiration (FEV1) expressed as percentage of predicted value. Postoperative FEV1 was predicted with dynamic perfusion MRI by semiquantitative assessment of the perfusion of whole lungs and resected segments of lungs, with quantitative assessment of functional lung volume on CT with commercially available software, with qualitative assessment of CT on the basis of the number of segments of total and resected lung, and with perfusion SPECT by assessment of uptake of microaggregated albumin particles in whole lungs and resected segments of lungs. Correlation and limits of agreement between actual and predicted postoperative FEV1 values were statistically evaluated. RESULTS Actual postoperative FEV1 had stronger correlation with postoperative FEV1 predicted from perfusion MRI (r = 0.87, p < 0.0001) and quantitative CT (r = 0.88, p < 0.0001) than with postoperative FEV1 predicted from qualitative CT (r = 0.83, p < 0.0001) and perfusion SPECT (r = 0.83, p < 0.0001). The limits of agreement between the actual postoperative FEV1 and postoperative FEV1 predicted from perfusion MRI (5.3% +/- 11.8% [mean +/- 2 SD]) were smaller than the values for postoperative FEV1 predicted from qualitative CT (6.8% +/- 14.4%) and perfusion SPECT (5.1% +/- 14.0%) and was almost equal to the value for postoperative FEV1 predicted from quantitative CT (5.0% +/- 11.6%). CONCLUSION Dynamic perfusion MRI is more accurate in prediction of the postoperative lung function of patients with lung cancer than are qualitative CT and perfusion SPECT and may be at least as accurate as quantitative CT.

STIR turbo SE MR imaging vs. coregistered FDG‐PET/CT: Quantitative and qualitative assessment of N‐stage in non‐small‐cell lung cancer patients

To conduct a prospective comparison of the accuracy of short inversion time (TI) inversion‐recovery (STIR) turbo spin‐echo (SE) imaging and coregistered 2‐[fluorine‐18] fluoro‐2‐deoxy‐D‐glucose (FDG)–positron emission tomography (PET) with computed tomography (CT) (coregistered FDG‐PET/CT) to assess the N‐stage in non‐small‐cell lung cancer (NSCLC) patients.