Prediction of pathological complete response after neoadjuvant chemotherapy in breast cancer: comparison of diagnostic performances of dedicated breast PET, whole-body PET, and dynamic contrast-enhanced MRI.

PURPOSE: To compare the diagnostic performance of ring-type dedicated breast PET (dbPET), whole-body PET (WBPET), and DCE-MRI for predicting pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). METHODS: This prospective study included 29 women with histologically proven breast cancer on needle biopsy between July 2016 and July 2019 (age: mean 55 years; range 35-78). Patients underwent WBPET followed by ring-type dbPET and DCE-MRI pre- and post-NAC for preoperative evaluation. pCR was defined as an invasive tumor that disappeared in the breast. Standardized uptake values corrected for lean body mass (SULpeak) were calculated for dbPET and WBPET scans. Maximum tumor length was measured in DCE-MRI images. Reduction rates were calculated for quantitative evaluation. Two radiologists independently evaluated the qualitative findings. Reduction rates and qualitative findings were compared between the pCR (n = 7) and non-pCR (n = 22) groups for each modality. Differences in quantitative and qualitative data between the two groups were analyzed statistically. RESULTS: Significant differences were observed in the reduction rates of dbPET and DCE-MRI (P = 0.01 and 0.03, respectively) between the two groups. Univariate and multiple logistic regression analyses revealed that SULpeak reduction rates in WBPET and dbPET (P = 0.02 and P = 0.01, respectively) and in dbPET (odds ratio, 16.00; 95% CI 1.57-162.10; P = 0.01) were significant indicators associated with pCR, respectively. No between-group differences were observed in qualitative findings in the three modalities. CONCLUSION: SULpeak reduction rate of dbPET > 82% was an independent indicator associated with pCR after NAC in breast cancer.

Restrictive mitral annuloplasty with or without surgical ventricular restoration in ischemic dilated cardiomyopathy with severe mitral regurgitation.

BACKGROUND: We assessed changes in left ventricular (LV) volume and function and in regional myocardial wall stress in noninfarcted segments after restrictive mitral annuloplasty (RMA) with or without surgical ventricular restoration (SVR). METHODS AND RESULTS: Thirty-nine patients with ischemic cardiomyopathy (ejection fraction ≤ 0.35) and severe mitral regurgitation (≥ 3) were studied before and 2.8 months after surgery with cine-angiographic multidetector computed tomography (cine-MDCT). Eighteen underwent RMA alone (RMA group) and 21 underwent RMA and SVR (RMA+SVR group). In addition to measuring conventional parameters (LV end-diastolic volume index [LVEDVI], LV end-systolic volume index [LVESVI], and LV ejection fraction), we evaluated the regional circumferential end-systolic wall stress and mean circumferential fiber shortening in both the basal and mid-LV regions using 3-dimensional cine-MDCT images. LV end-diastolic and end-systolic volume indexes were significantly greater in the RMA+SVR group than in the RMA group preoperatively, but these values did not differ significantly postoperatively. LV end-diastolic and end-systolic volume indexes decreased significantly, by 21% and 27% after RMA and by 35% and 42% after RMA and SVR, and the percent reductions in LV end-diastolic and end-systolic volume indexes were significantly larger in the RMA+SVR group. Regional end-systolic wall stress decreased and circumferential fiber shortening increased significantly in the noninfarcted regions after RMA with or without SVR. CONCLUSIONS: RMA plus SVR showed a potentially greater reduction of LV end-diastolic and end-systolic volume indexes than RMA alone. In selected patients with more advanced LV remodeling, concomitant SVR may favorably affect the LV reverse-remodeling process induced by RMA.

Mechanism of beneficial effects of restrictive mitral annuloplasty in patients with dilated cardiomyopathy and functional mitral regurgitation.

BACKGROUND: Restrictive mitral annuloplasty (RMA) often leads to reverse left ventricular (LV) remodeling in patients with advanced cardiomyopathy and functional mitral regurgitation. However, the mechanism responsible for its favorable effects on LV ejection performance has been poorly understood. We evaluated systolic wall stress using cineangiographic multidetector computed tomography (MDCT) and our developed software system to assess stress-shortening relations before and after RMA. METHODS AND RESULTS: Twenty-four patients with dilated cardiomyopathy underwent 64-row MDCT before and 2 months after RMA. All patients underwent stringent downsizing annuloplasty with a semirigid complete ring. Reconstructed images were used to calculate LV end-diastolic index (EDVI) and end-systolic volume index (ESVI), LV ejection fraction, and regional and global end-systolic wall stress (ESS). After RMA, LVEDVI and LVESVI decreased from 151±52 to 131±53 mL/m(2) (P=0.0001) and from 114±48 to 92±50 mL/m(2) (P=0.0001), respectively. Global ESS decreased from 157±43 to 139±50 kdyne/cm(2) (P=0.01), and LV ejection fraction improved from 27±8.0 to 33±13% (P=0.0007). There were significant correlations between change in LVEDVI and LVESVI (r=0.88, P<0.0001) and change in LVESVI and global ESS (r=0.68, P=0.0002). Moreover, the magnitude of increase in LV ejection fraction significantly correlated with the degree of reduction in global ESS (r=-0.61, P=0.002). Patients without significant reverse LV remodeling had significantly higher preoperative and postoperative global ESS than those with it. CONCLUSIONS: Our study suggests that decrease in afterload after reduction in volume overload was responsible for postoperative reverse LV remodeling process after RMA.

Left ventricular basal myocardial scarring detected by delayed enhancement magnetic resonance imaging predicts outcomes after surgical therapies for patients with ischemic mitral regurgitation and left ventricular dysfunction.

BACKGROUND: Treatment of heart failure by surgical procedures such as mitral annuloplasty and left ventricular (LV) restoration is increasingly applied to patients with ischemic mitral regurgitation (IMR) and LV dysfunction. The clinical efficacy of delayed enhancement magnetic resonance imaging (DE-MRI) was studied to predict LV functional recovery and adverse outcomes after these therapies. METHODS AND RESULTS: In 26 patients with IMR and a LV ejection fraction < 40%, DE-MRI was performed before the operation and the percentage of regional myocardial scarring was quantified at the basal, mid, and apical LV. Calculated percentage of fibrosis was 12 ± 12% at the base, 24 ± 15% at the mid, and 35 ± 31% at the apical LV. The degree of basal fibrosis was a significant predictor of less improvement of LV ejection fraction and postoperative restrictive diastolic filling. A linear correlation was noted between basal fibrosis and postoperative ejection fraction (P = 0.001, R = -0.61), the early to late mitral valve flow ratio (P = 0.0005, R = 0.66), and deceleration time (P = 0.01, R = -0.51). Logistic regression analysis demonstrated that the percentage of basal fibrosis was the independent predictor of postoperative adverse clinical outcomes (odds ratio, 1.26; P = 0.04). CONCLUSIONS: In patients undergoing surgical heart failure therapy for IMR, the extent of basal fibrosis characterized by DE-MRI might be a useful predictor of postoperative LV systolic and diastolic functional recovery and postoperative adverse outcomes.

(18)F-FDG accumulation in the oral cavity is associated with periodontal disease and apical periodontitis: an initial demonstration on PET/CT.

OBJECTIVE: The objective of this study was to prospectively investigate the relationship between high accumulation of 2-deoxy-2-[(18)F] fluoro-D: -glucose (FDG) in the oral cavity and dental infections on positron emission tomography/computed tomography (PET/CT). METHODS: FDG-PET/CT scans of 103 patients who underwent a health screening were evaluated. The dental examination was performed prior to each PET/CT scan, and dental infections were assessed. Dental infections were classified into six blocks. The severity of dental caries was classified into five grades, and periodontal disease and apical periodontitis were classified into three grades. Two radiologists classified the PET images in the same manner as the dental examination. They evaluated the intensity of FDG uptake by a four-point visual PET image score for each block. The comparison of the dental examination, as a gold standard, and the visual PET image score was performed on a patient or block basis. RESULTS: On a patient-based analysis, 21 of 103 patients (20.4%) showed PET positive findings in the oral cavity; 18 of the 21 patients (85.7%) had dental infections. On a block-based analysis, 25 of 605 blocks (4.1%) showed PET positive findings in the oral cavity; 22 of the 25 blocks (88.0%) had dental infections. On a detailed block-based analysis, a significant difference was observed between the presence of periodontal disease, or apical periodontitis and the positivity of the visual PET image findings (P < 0.01). Their severity correlated with the visual PET image score (P < 0.05). CONCLUSIONS: Periodontal disease or apical periodontitis, but not dental caries, caused FDG accumulation in the oral cavity. This finding should be taken into account when a head and neck FDG-PET study is interpreted.

Computer-assisted lung nodule volumetry from multi-detector row CT: influence of image reconstruction parameters.

PURPOSE: To investigate differences in volumetric measurement of pulmonary nodules caused by changing the reconstruction parameters for multi-detector row CT. MATERIALS AND METHODS: Thirty-nine pulmonary nodules less than 2 cm in diameter were examined by multi-slice CT. All nodules were solid, and located in the peripheral part of the lungs. The resultant 48 parameters images were reconstructed by changing slice thickness (1.25, 2.5, 3.75, or 5 mm), field of view (FOV: 10, 20, or 30 cm), algorithm (high-spatial frequency algorithm or low-spatial frequency algorithm) and reconstruction interval (reconstruction with 50% overlapping of the reconstructed slices or non-overlapping reconstruction). Volumetric measurements were calculated using commercially available software. The differences between nodule volumes were analyzed by the Kruskal-Wallis test and the Wilcoxon Signed-Ranks test. RESULTS: The diameter of the nodules was 8.7+/-2.7 mm on average, ranging from 4.3 to 16.4mm. Pulmonary nodule volume did not change significantly with changes in slice thickness or FOV (p>0.05), but was significantly larger with the high-spatial frequency algorithm than the low-spatial frequency algorithm (p<0.05), except for one reconstruction parameter. The volumes determined by non-overlapping reconstruction were significantly larger than those of overlapping reconstruction (p<0.05), except for a 1.25 mm thickness with 10 cm FOV with the high-spatial frequency algorithm, and 5mm thickness. The maximum difference in measured volume was 16% on average between the 1.25 mm slice thickness/10 cm FOV/high-spatial frequency algorithm parameters and overlapping reconstruction. CONCLUSION: Volumetric measurements of pulmonary nodules differ with changes in the reconstruction parameters, with a tendency toward larger volumes in high-spatial frequency algorithm and non-overlapping reconstruction compared to the low-spatial frequency algorithm and overlapping reconstruction.

Electrocardiography-triggered high-resolution CT for reducing cardiac motion artifact: evaluation of the extent of ground-glass attenuation in patients with idiopathic pulmonary fibrosis.

PURPOSE: The aim of this study was to evaluate the decreasing of cardiac motion artifact and whether the extent of ground-glass attenuation of idiopathic pulmonary fibrosis (IPF) was accurately assessed by electrocardiography (ECG)-triggered high-resolution computed tomography (HRCT) by 0.5-s/rotation multidetector-row CT (MDCT). MATERIALS AND METHODS: ECG-triggered HRCT were scanned at the end-diastolic phase by a MDCT scanner with the following scan parameters; axial four-slice mode, 0.5 mm collimation, 0.5-s/rotation, 120 kVp, 200 mA/rotation, high-frequency algorithm, and half reconstruction. In 42 patients with IPF, both conventional HRCT (ECG gating(-), full reconstruction) and ECG-triggered HRCT were performed at the same levels (10-mm intervals) with the above scan parameters. The correlation between percent diffusion of carbon monoxide of the lung (%DLCO) and the mean extent of ground-glass attenuation on both conventional HRCT and ECG-triggered HRCT was evaluated with the Spearman rank correlation coefficient test. RESULTS: The correlation between %DLCO and the mean extent of ground-glass attenuation on ECG-triggered HRCT (observer A: r = -0.790, P < 0.0001; observer B: r = -0.710, P < 0.0001) was superior to that on conventional HRCT (observer A: r = -0.395, P < 0.05; observer B: r = -0.577, P = 0.002) for both observers. CONCLUSION: ECG-triggered HRCT by 0.5 s/rotation MDCT can reduce the cardiac motion artifact and is useful for evaluating the extent of ground-glass attenuation of IPF.

Phase I Clinical Trial of Autologous Stem Cell-Sheet Transplantation Therapy for Treating Cardiomyopathy.

BACKGROUND: When transplanted into failing heart, autologous somatic tissue-derived cells yield functional recovery via paracrine effects that enhance native regeneration. However, the therapeutic effects are modest. We developed a method in which scaffold-free cell sheets are attached to the epicardial surface to maximize paracrine effects. This Phase I clinical trial tested whether transplanting autologous cell-sheets derived from skeletal muscle is feasible, safe, and effective for treating severe congestive heart failure. METHODS AND RESULTS: Fifteen ischemic cardiomyopathy patients and 12 patients with dilated cardiomyopathy, who were in New York Heart Association functional class II or III and had been treated with the maximum medical and/or interventional therapies available, were enrolled. Scaffold-free cell sheets of 3 to 9×108 cells derived from autologous muscle were transplanted over the LV free wall via left thoracotomy, without additional interventional treatments. There were no procedure-related major complications during follow-up. The majority of the ischemic cardiomyopathy patients showed marked symptomatic improvement in New York Heart Association classification (pre: 2.9±0.5 versus 6 months: 2.1±0.4, P<0.01; 1 year: 1.9±0.3, P<0.01) and the Six-Minute Walk Test with significant reduction of serum brain natriuretic peptide level (pre: 308±72 pg/mL versus 6 months: 191±56 versus 1 year: 182±46, P<0.05), pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vein resistance, and left ventricular wall stress after transplantation instead of limited efficacy in dilated cardiomyopathy patients. CONCLUSIONS: Cell-sheet transplantation as a sole therapy was feasible for treating cardiomyopathy. Promising results in the safety and functional recovery warrant further clinical follow-up and larger studies to confirm this treatment's efficacy for severe congestive heart failure. CLINICAL TRIAL REGISTRATION: URL: http://www.umin.ac.jp/english/. Unique identifier: UMIN000003273.

Evaluation of the usefulness of color digital summation radiography in temporally sequential digital radiographs: a phantom study.

PURPOSE: The purpose of this study was to assess the usefulness of color digital summation radiography (CDSR) for detection of nodules on chest radiographs by observers with different levels of experience. MATERIALS AND METHODS: A total of 30 radiographs of chest phantoms with abnormalities and 30 normal ones were arranged at random. Set A was conventional radiographs only. Set B consisted of both conventional radiographs and CDSR images, which were colored with magenta. Five chest radiologists and five residents evaluated both image sets on a TFT monitor. The observers were asked to rate each image set using a continuous rating scale. The reading time for each set was also recorded. RESULTS: In set A, the performance of chest radiologists was significantly superior to that of the residents (P < 0.05). However, in set B, there was no significant difference in the performance of the chest radiologists and the residents. In both observer groups, the mean reading time per case in set B was significantly shorter than that in set A (P < 0.01). CONCLUSION: By using CDSR, the detection capability of observers with little experience improves and is comparable to that of experienced observers. Moreover, the reading time becomes much shorter using CDSR.

Evaluation of coronary artery bypass grafts using multidetector-row CT with Japanese patients.

PURPOSE: To evaluate the patency of coronary artery bypass grafting (CABG) with multidetector-row computed tomography (MDCT) in Japanese patients, who have narrower coronary arteries than Caucasians. MATERIALS AND METHODS: Nineteen patients (12 men and 7 women, mean age: 63 +/- 12 years) with 33 coronary bypass grafts were examined with three-dimensional volume rendering (3D-VR) and curved multiplanar reconstruction (MPR) of MDCT. All grafts were compared with those obtained with selective graft angiography. RESULTS: For the 19 patients with 33 grafts, the overall sensitivity and specificity, compared with those for selective bypass angiography, were 96.7% and 100%, respectively. CONCLUSION: The patency of CABG in Japanese patients can be effectively evaluated with 3D-VR and curved MPR of MDCT.

MR imaging of thymic epithelial tumors: correlation with World Health Organization classification.

PURPOSE: The aim of this study was to determine magnetic resonance imaging (MRI) features of various subtypes of thymic epithelial tumors based on the World Health Organization classification. MATERIALS AND METHODS: The study included 64 patients with histologically proven thymic epithelial tumors. Two observers evaluated the MRI findings in terms of tumor size, contour, lobulation, shape, homogeneity, the presence of intratumor high- and low-signal foci, enhancement degree and pattern, the presence of capsule and septum, and associated mediastinal lymphadenopathy and pleural effusion. RESULTS: Type A tumors were more likely to have a smooth contour, round shape, distinct capsule, and smaller size compared to any other type of thymic epithelial tumor. Thymic carcinomas demonstrated a higher prevalence of low-signal foci within the mass on T2-weighted images and mediastinal lymphadenopathy than any other types. The frequency of heterogeneous intensity on T2-weighted images increased from type A tumors to thymic carcinomas. CONCLUSION: The presence of a smooth contour, round shape, and capsule is highly suggestive of a type A tumor. Foci of low signal intensity in the mass on T2-weighted images and mediastinal lymphadenopathy are highly suggestive of thymic carcinomas.

Evaluation of usefulness of color digital summation radiography for solitary pulmonary nodules on chest radiographs.

PURPOSE: The aim of this study was to evaluate the usefulness of novel color digital summation radiography (CDSR) for detecting solitary pulmonary nodules on chest radiographs by observers with different levels of experience. MATERIALS AND METHODS: A total of 30 healthy controls and 30 patients with newly detected solitary pulmonary nodules were evaluated. Six radiologists and five residents evaluated three image sets: set A, current and prior radiographs only; set B, set A with temporal subtraction images; and set C, set A with CDSR. The observers were asked to rate each image set using a continuous rating scale. In addition, the reading time required for each set was recorded. RESULTS: The radiologists showed no significant differences in the mean A(z) value between set A, set B, and set C. However, the residents showed significant differences between set A and set B and between set A and set C. In addition, for set B and set C, the mean reading time per case of all readers was significantly shorter than that for set A. CONCLUSION: The detection capability of observers with little experience is comparable to that of experienced observers when reading radiographs with temporal subtraction images or with CDSR. The usefulness of CDSR is comparable to that of temporal subtraction.

Air microbubbles as MR susceptibility contrast agent at 1.5 Tesla.

Air microbubbles have been investigated recently at high magnetic field strength (2 Tesla or greater) as potential MR susceptibility contrast agents. We used a phantom to measure their susceptibility at 1.5 T to clarify their usefulness for this purpose. The phantom, filled with fresh Levovist suspension at 4 different doses (67 to 125 mg/mL), was continuously scanned with a gradient-echo technique at a temporal resolution of 10 s. The transverse relaxation increase (R2*) by microbubbles demonstrated a time course of exponential decay at each dose (time-constant, 39 to 57 s). The dependency of R2* on microbubble volume fraction was linear, with a slope of 89 s-1 per percentage microbubble volume fraction. Our study represents the first step towards applying microbubbles as susceptibility contrast agents at 1.5 T.

Computational flow dynamics in abdominal aortic aneurysm using multislice computed tomography.

Following the introduction of a new multislice computed tomography (MSCT) scanner, it has become possible to produce high-speed CT angiography (CTA), the preferred method for imaging in emergent abdominal vascular conditions. Unlike catheter angiography, multislice CTA not only depicts the vessels but also allows perfusion in adjacent organs to be assessed. To make the most effective diagnostic use of multi-detector row CTA and three-dimensional image post-processing, radiologists must be familiar with the optimal CTA protocols and the typical CT findings in various emergent vascular conditions using computational flow dynamics (CFD). This article describes a technical approach to estimating the blood flow state of human abdominal aortic aneurysms (AAA) in more detail by constructing realistic three-dimensional (3D) vessel models using CFD methods, focusing on pre- and postoperative cases.

Prevalence, Concomitance, and Distribution of Ossification of the Spinal Ligaments: Results of Whole Spine CT Scans in 1500 Japanese Patients.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To investigate the prevalence, concomitance, and distribution of various types of ossification of the spinal ligaments in healthy subjects using computed tomography (CT). SUMMARY OF BACKGROUND DATA: CT has better diagnostic accuracy for ossification of the spinal ligaments compared to plain radiography. Currently there is no study that examines the prevalence of ossification of the spinal ligaments using whole spine CT scans. METHODS: One thousand five hundred Japanese patients (888 men and 612 women) who underwent positron emission tomography and CT (PETCT) in a private health check center between 2006 and 2013 were included. This PETCT was performed on self-paying participants as a preventive cancer screen. Existence of ossification of the posterior longitudinal ligament (OPLL), ligamentum flavum (OLF), anterior longitudinal ligament (OALL), diffuse idiopathic skeletal hyperostosis (DISH), and nuchal ligament (ONL) was examined. RESULTS: The prevalence of spinal ligament ossifications was found to be 6.3% in cervical OPLL (8.3% in men and 3.4% in women), 23% in ONL (33% in men and 8.8% in women), 1.6% in thoracic OPLL (1.4% in men and 2.0% in women), 12% in thoracic OLF (15% in men and 7.7% in women), 37% in thoracolumbar OALL (45% in men and 26% in women), and 12% in DISH (16% in men and 6.2% in women). Thirteen percent of patients with cervical OPLL had thoracic OPLL, 34% of cervical OPLL had thoracic OLF, 45% of cervical OPLL had ONL, and 36% of cervical OPLL had DISH. The most common level was C5 for cervical OPLL, T1/2 for thoracic OPLL, T11 for thoracic OLF, and T8/9 for OALL. CONCLUSION: Accurate prevalence of various types of ossification of the spinal ligaments evaluated by CT was revealed. High concomitance was observed in each classification of spinal ligament ossification. LEVEL OF EVIDENCE: 3.

Mid-term results of freestyle aortic stentless bioprosthetic valve: clinical impact of quantitative analysis of in-vivo three-dimensional flow velocity profile by magnetic resonance imaging.

BACKGROUND AND AIM OF THE STUDY: The study aim was to investigate the in-vivo flow profiles of a stentless aortic bioprosthetic valve by MRI flow quantification, and to identify the clinical implication of prosthesis size and implantation method. METHODS: Twenty-six patients with a Freestyle stentless aortic bioprosthetic valve were studied using three-dimensional flow velocity profile by MRI, and compared with four patients with a stented aortic bioprosthetic valve and four healthy volunteers. Flow velocity profiles were analyzed quantitatively by the hydromechanics parameter, mean to peak velocity ratio at peak systole and compared with parameters monitored echocardiographically. RESULTS: In larger-sized valves or full root implantation, flow profiles showed an optimal pattern with low gradients, a high mean to peak velocity ratio, and minimum disturbance which approximated that of a normal valve. By contrast, a subset of patients, notably with 21 mm valves and subcoronary implantation, showed suboptimal flow pattern with high gradient and low mean to peak velocity ratio which approximated that of stented valves. The mean to peak velocity ratio was more strongly related to peak velocity than to the indexed effective orifice area. CONCLUSION: Although stentless aortic bioprostheses have excellent hemodynamic performance, some patients show suboptimal results. This seems to occur more often when the subcoronary technique is used, and especially with 21-mm valves. Care must be taken when using the subcoronary technique with a 21-mm valve in patients with a small body surface area.

Image quality of high-resolution CT with 16-channel multidetector-row CT: comparison between helical scan and conventional step-shoot scan.

OBJECTIVE: The aim of this study was to evaluate the image quality of high-resolution CT (HRCT) reconstructed from volumetric data with 16-channel multidetector-row CT (MDCT). SUBJECTS AND METHODS: Eleven autopsy lungs that were diagnosed histopathologically were scanned by 16-channel MDCT with the step-and-shoot scan mode and three helical scan modes. Each helical mode had each size of focal spot, pitch, and time of gantry rotation. HRCT images were reconstructed from the volumetric data with each helical mode and axial sequence data. Two observers evaluated the image quality and noted the most appropriate diagnosis for each imaging. RESULTS: Visualization of abnormal structures with one helical mode was equal to those with axial mode, whereas those with the other two helical modes were inferior to those with axial mode (Wilcoxon signed rank test; p<0.0001). There was no significant difference in diagnostic efficacy between modes. CONCLUSION: The image quality of HRCT with appropriate helical mode is equal to that with axial mode and diagnostic efficacy is equal among all modes. These results may indicate that sufficient HRCT images can be obtained by only one helical scan without the addition of conventional axial scans.

Aortic compliance in patients with aortic regurgitation: evaluation with magnetic resonance imaging.

PURPOSE: To assess by means of cine magnetic resonance imaging (MRI) aortic compliance before and after aortic valve replacement (AVR with SJM valve) in patients with aortic regurgitation (AR). MATERIALS AND METHODS: Two groups (healthy controls and patients with severe isolated AR) of 10 subjects each were included in this study. Cine MRI was performed at three locations of the aorta, and aortic compliance was calculated by dividing the maximum change in the aortic area by pulse pressure. RESULTS: Cine MRI is useful to assess abnormalities of aortic compliance in patients with AR. Compared with the control group, aortic compliance in the AR group was significantly less in the ascending aorta (p<0.05), decreasing in order of aortic location. After AVR, aortic compliance improved for all locations. CONCLUSION: Cine MRI enables assessment of aortic biophysical properties such as a compliance for evaluating the progression of AR and the efficacy of treatment.

Full-size digital storage phosphor chest radiography: effect of 4K versus 2K matrix size on observer performance in detection of subtle interstitial abnormalities.

PURPOSE: To compare observer performance in the detection of subtle interstitial abnormalities on 3,520 x 3,520 (4K) matrix and 1,760 x 1,760 (2K) matrix full-size digital storage phosphor (DSP) chest radiographs. MATERIALS AND METHODS: Thirty-five 4K DSP chest radiographs with subtle interstitial abnormalities (n=27) or normal lungs (n=8) were processed with a half-band low-pass filter to produce 2K DSP radiographs. Although the actual matrix size of the 2K DSP radiographs remained 4K, the effective matrix size was reduced to 2K. Four chest radiologists independently evaluated full-sized hard-copy of the 4K and 2K DSP radiographs, and scored the presence of interstitial abnormalities for both right and left lungs on a five-point confidence scale. With findings on high-resolution computed tomography as the reference standard, observer performance was evaluated using multireader-multicase receiver operating characteristic (ROC) analysis. RESULTS: The average area under the ROC curve (Az) values for 4K and 2K DSP radiographs were 0.791+/-0.055 and 0.804+/-0.050, respectively. Both individual and averaged Az values showed no statistically significant differences (p>0.05) between 4K and 2K DSP radiographs. CONCLUSION: Observer performance in the detection of subtle interstitial abnormalities on 4K full-size DSP chest radiographs was equivalent to that on 2K full-size DSP chest radiographs.

Voxel dimensions required for micromorphologic evaluation of ground-glass opacity on lung high-resolution CT.

PURPOSE: To clarify the appropriate voxel dimensions required for pathologic evaluation of areas with ground-glass opacity on lung high-resolution computed tomography (HRCT). MATERIALS AND METHODS: Synchrotron radiation CT (SRCT) images of autopsied lung speci-mens (n=25) that showed ground-glass opacity on HRCT were reconstructed with 12 different voxel dimensions ranging from 0.006 to 0.6 mm. The specimens were micromorphologically categorized into one of three pathologic groups: alveolar, interstitial, and mixed abnormalities. Each SRCT image was independently diagnosed as one of three pathologic groups by six chest radiologists. The diagnostic accuracy required to estimate the appropriate voxel dimensions was compared among different voxel dimensions by means of the Tukey test. RESULTS: Diagnostic accuracy with voxel dimensions less than or equal to 0.06 mm was significantly higher than that with voxel dimensions of 0.18 mm or more (p<0.01). There was, however, no significance of difference in diagnostic accuracy with voxel dimensions of less than or equal to 0.06 mm. In addition, no significant difference in diagnostic accuracy was found with voxel dimensions of 0.18 mm or more. CONCLUSION: The appropriate voxel dimensions are approximately 0.06 mm for pathologic differentiation of areas with ground-glass opacity on HRCT.