Nobukazu Aoyama

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.

Diffusion-weighted MRI versus 18F-FDG PET/CT: performance as predictors of tumor treatment response and patient survival in patients with non-small cell lung cancer receiving chemoradiotherapy.

OBJECTIVE The purpose of this study was to compare the predictive capabilities of diffusion-weighted MRI (DWI) and 18F-FDG PET/CT for tumor response to therapy and survival in patients with non-small cell lung cancer (NSCLC) receiving chemoradiotherapy. SUBJECTS AND METHODS The study included 64 patients with NSCLC diagnosed as stage III who underwent pretherapeutic DWI and FDG PET/CT and were treated with chemoradiotherapy. For quantitative prediction, apparent diffusion coefficient (ADC) for DWI and maximum standardized uptake value (SUVmax) for PET/CT were measured at all targeted lesions and averaged to obtain final values for each patient. To evaluate the predictive capability of either index for distinguishing partial response and nonresponse (stable or progressive disease) groups, receiver operating characteristic analysis was performed, and sensitivity, specificity, and accuracy of the two modalities were compared using the McNemar test. Finally, overall and progression-free survival curves divided by the corresponding threshold value were compared by means of the log-rank test. RESULTS The area under the curve (Az) for ADC (Az=0.84) was significantly larger than that for SUVmax (Az=0.64, p<0.05). The application of feasible threshold values resulted in specificity (44.4%) and accuracy (76.6%) of DWI becoming significantly higher than those of PET/CT (specificity, 11.1%; p<0.05 and accuracy, 67.2%, p<0.05). In addition, only overall survival and progression-free survival of the two groups divided by ADC at 2.1×10(-3) mm2/s and SUVmax at 10 showed a significant difference (p<0.05). CONCLUSION DWI may have better potential than FDG PET/CT for prediction of tumor response to therapy in NSCLC patients before chemoradiotherapy.

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.

A preliminary study of the T1rho values of normal knee cartilage using 3 T-MRI

INTRODUCTION To investigate the degree of the effect of aging and weight-bearing on T1rho values in normal cartilage. MATERIALS AND METHODS Thirty-two asymptomatic patients were examined using 3.0-T magnetic resonance imaging (MRI) to determine knee cartilage T1rho values and T2 values. The femoral and tibial cartilage was divided into weight-bearing (WB-Rs) and less-weight-bearing (LWB-Rs) regions. Single regression analysis was used to assess the relationship between cartilage T1rho values and age and between T2 values and age. Analysis of variance and post hoc-testing were used to evaluate differences in WB-Rs and LWB-Rs cartilage T1rho values and T2 values. Multiple linear regression modeling was performed to predict cartilage T1rho values. RESULTS Cartilage T1rho values correlated positively with age for all cartilage regions tested (p<0.001). There were no significant correlations between cartilage T2 values and age. In both the medial femoral and tibial cartilage, T1rho values were significantly higher in WB-Rs than in LWB-Rs (p<0.05). There were no significant differences in T2 values between WB-Rs and LWB-Rs. Multiple linear regression analysis showed that both age and weight-bearing were significant predictors of increased medial knee cartilage T1rho values (p<0.001). CONCLUSIONS Aging and the degree of weight-bearing correlate with the change in cartilage T1rho values. Based on multiple regression modeling, aging may be a more important factor than weight-bearing for cartilage T1rho values.

Triexponential function analysis of diffusion‐weighted MRI for diagnosing prostate cancer

To evaluate more detailed information noninvasively through on diffusion and perfusion in prostate cancer (PCa) using triexponential analysis of diffusion‐weighted imaging (DWI).

Neuroimaging features of xeroderma pigmentosum group A

Xeroderma pigmentosum group A (XPA) is a hereditary dermatological disease in which hypersensitivity to ultraviolet radiation and various neurological symptoms are observed. In this study, to evaluate the degeneration occurring in the brain of XPA patients, neurological examinations by an established neurologist and 3‐Tesla magnetic resonance imaging (MRI) were performed in 10 Japanese XPA patients. MRI studies included diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) in addition to conventional sequences. Neurological examinations revealed various deteriorations in the both central and peripheral nervous systems in all subjects. MRI studies demonstrated age‐dependent decline in multimodalities. Severe brain atrophy in conventional sequences, decreased fractional anisotropy (FA) value in DTI, and reduced NAA/Cre ratio in MRS were observed in the adult patients. Multimodal MRI studies unmask the neurological deterioration in XPA patients.

Abdominal apparent diffusion coefficient measurements: effect of diffusion-weighted image quality and usefulness of anisotropic images

This study aimed to assess the effect of diffusion-weighted image (DWI) quality on abdominal apparent diffusion coefficient (ADC) measurements and the usefulness of anisotropic images. Twenty-six patients (10 men and 16 women; mean, 58.1 years) who underwent DW imaging and were diagnosed not to have any abdominal diseases were analyzed. Single-shot spin-echo echo-planar DW imaging was performed, and one isotropic and three orthogonal anisotropic images were created. ADCs were calculated for liver (four segments), spleen, pancreas (head, body, tail) and renal parenchyma. Image quality for each organ part was scored visually. We estimated the correlation between ADC and image quality and evaluated the feasibility of using anisotropic images. ADCs and image quality were affected by motion probing gradient directions in the liver and pancreas. A significant inverse correlation was found between ADC and image quality. The r values for isotropic images were -.46, -.48, -.70 and -.28 for the liver, spleen, pancreas and renal parenchyma, respectively. Anisotropic images had the best quality and lowest ADC in at least one organ part in 17 patients. DWIs with the best quality among isotropic and anisotropic images should be used in the liver and pancreas.

Magnetic resonance imaging (MRI) of articular cartilage of the knee using ultrashort echo time (uTE) sequences with spiral acquisition

The objective of this study was to evaluate the sensitivity of ultrashort echo time (uTE) sequence for visualisation of calcified deep layers of articular cartilage. MRI with a uTE sequence was performed on five healthy volunteers. Signals from the calcified deep layers of the articular knee cartilage were evaluated on uTE subtraction images and computed tomography images. The calcified deep layers of the articular cartilage changed from having a low to a high signal when imaged with a uTE sequence. The reported uTE sequence was effective in imaging the deep layers of the knee cartilage.

Contrast-enhanced multidetector-row computed tomography vs. Time-resolved magnetic resonance angiography vs. contrast-enhanced perfusion MRI: assessment of treatment response by patients with inoperable chronic thromboembolic pulmonary hypertension.

To compare therapeutic effect assessment capability of multidetector‐row computed tomography (MDCT), magnetic resonance angiography (MRA), and dynamic perfusion MRI for chronic thromboembolic pulmonary hypertension (CTEPH) patients.