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Purpose:Thermal rheology (TR) fluid, which comprises polyethylene (PE) particles, their dispersant, and solvent, is a material that increases in viscosity to various degrees depending on the type and ratio of these constituents when its temperature rises. The viscosity of type 1 (TRF-1) increases more than that of type 2 (TRF-2) near rabbit body temperature. This preliminary animal study aimed to determine the basic characteristics and embolic effect of TR fluid by comparing TRF-1 and TRF-2., Materials and methods:Twenty-four Japanese white rabbits underwent unilateral renal artery embolization using TRF-1 or TRF-2 and follow-up angiography at 7 or 28 days (4 subgroups, n = 6 each). Subsequently, the rabbits were euthanized, and the embolized kidneys were removed for pathological examination. The primary and final embolization rates were defined as the ratio of renal artery area not visible immediately after embolization and follow-up angiography, respectively, to visualized renal artery area before embolization. The final embolization rate and maximum vessel diameter filled with PE particles were compared between materials. Moreover, the embolic effect was determined to be persistent when a two-sided 95% confidence interval (CI) for the difference in means between the embolization rates was < 5%., Results:The final embolization rate was significantly higher for the TRF-1 than for the TRF-2 at both 7 (mean 80.7% [SD 18.7] vs. 28.4% [19.9], p = 0.001) and 28 days (94.0% [3.5] vs. 37.8% [15.5], p < 0.001). The maximum occluded vessel diameter was significantly larger for TRF-1 than for TRF-2 (870 µm [417] vs. 270 µm [163], p < 0.001). The embolic effect of TRF-1 was persistent until 28 days (difference between rates - 3.3 [95% CI - 10.0-3.4])., Conclusion:The embolic effect of TRF-1 was more persistent than that of TRF-2, and the persistency depended on the type and ratio of TR fluid constituents.

Background Localized pleural adhesion (LPA) evaluation in the apical region is difficult even with four-dimensional ultra-low-dose computed tomography (4D-ULDCT) in the supine position due to smaller pleural movements. Purpose To assess usability of 4D-ULDCT in the lateral decubitus (LD) position for LPA detection in the apical region. Material and Methods Forty-seven patients underwent 4D-ULDCT of a single respiration cycle with 16-cm coverage of body axis in supine and LD positions with the affected lung uppermost. Intraoperative thoracoscopic findings confirmed LPA presence. A pleural point and a corresponding point on costal outer edge were placed in identical axial planes at end-inspiration. Pleuro-chest wall distance between two points (PCD) was calculated at each respiratory phase. In the affected lung, average change in amount of PCD (PCDACA) was compared between patients with and without LPA in total and two sub-groups (non-COPD and COPD, non-emphysematous and emphysematous patients) in supine and non-dependent (ND) LD positions. Receiver operating characteristic (ROC) curve analysis was performed to determine optimal thresholds in PCDACA for differentiating patients with LPA from those without. Results In COPD/emphysematous patients and total population, PCDACA with LPA was smaller than in those without in the supine and NDLD positions for overall, lateral, and dorsal regions. For the lateral region in COPD patients, area under ROC curve (AUC) increased from supine (0.64) to NDLD position (0.81). For the dorsal region in emphysematous patients, AUC increased from supine (0.76) to NDLD position (0.96). Conclusion 4D-ULDCT in LD position may be useful for LPA detection in apical regions for COPD and/or emphysematous patients.

We aimed to reveal specific findings of gastrointestinal stromal tumors (GISTs) in the small intestine on contrast-enhanced computed tomography (CT) by comparing GISTs with non-GISTs. We enrolled 28 patients with 39 GISTs and 20 patients with 22 non-GISTs who underwent enterectomy with a preoperative diagnosis of small intestinal tumor. All lesions were diagnosed by histopathological examination. Two radiologists independently evaluated internal homogeneity, growth pattern, calcification, intratumoral hemorrhage, degeneration, ulceration, and lymphadenopathy and measured the maximum diameter of the tumor and contrast-enhanced CT (CECT) value of the solid portion as well as the diameter and CT value of the feeding artery and drainage vein on CECT in the arterial and venous phases. Intratumoral hemorrhage was seen in 15.4% and 25.6% of GISTs and in 0% and 0% of non-GISTs (p = 0.079 and 0.010), with good interobserver agreement (κ = 0.715). The drainage vein diameter correlated well with the maximum diameter of the tumor (r = 0.744, p

Purpose To assess the usefulness of software analysis using dynamic-ventilation CT for localized pleural adhesion (LPA). Materials and methods Fifty-one patients scheduled to undergo surgery underwent both dynamic-ventilation CT and static chest CT as preoperative assessments. Five observers independently evaluated the presence and severity of LPA on a three-point scale (non, mild, and severe LPA) for 9 pleural regions (upper, middle, and lower pleural aspects on ventral, lateral, and dorsal areas) on the chest CT by three different methods by observing images from: static high-resolution CT (static image); dynamic-ventilation CT (movie image), and dynamic-ventilation CT while referring to the adhesion map (movie image with color map), which was created using research software to visualize movement differences between the lung surface and chest wall. The presence and severity of LPA was confirmed by intraoperative thoracoscopic findings. Parameters of diagnostic accuracy for LPA presence and severity were assessed among the three methods using Wilcoxon signed rank test in total and for each of the three pleural aspects. Results Mild and severe LPA were confirmed in 14 and 8 patients. Movie image with color map had higher sensitivity (56.9 ± 10.7 %) and negative predictive value (NPV) (91.4 ± 1.7 %) in LPA detection than both movie image and static image. Additionally, for severe LPA, detection sensitivity was the highest with movie image with color map (82.5 ± 6.1 %), followed by movie image (58.8 ± 17.0 %) and static image (38.8 ± 13.9 %). For LPA severity, movie image with color map was similar to movie image and superior to static image in accuracy as well as underestimation and overestimation, with a mean value of 80.2 %. Conclusion Software-assisted dynamic-ventilation CT may be a useful novel imaging approach to improve the detection performance of LPA.

Background It is still unclear which image reconstruction algorithm is appropriate for peripheral bronchial luminal conspicuity (PBLC) on dynamic-ventilation computed tomography (DVCT). Purpose To assess the influence of radiation doses and temporal resolution (TR) on the association between movement velocity (MV) and PBLC on DVCT. Material and Methods An ex vivo porcine lung phantom with simulated respiratory movement was scanned by 320-row CT at 240 mA and 10 mA. Peak and dip CT density and luminal area adjusted by values at end-inspiration (CTDpeak and CTDdip, luminal area ratio [LAR]) for PBLC and MVs were measured and visual scores (VS) were obtained at 12 measurement points on 13 frame images obtained at half and full reconstructions (TR 340 and 190 ms) during expiration. Size-specific dose estimate (SSDE) was applied to presume radiation dose. VS, CTDpeak, CTDdip, LAR, and their cross-correlation coefficients with MV (CCC) were compared among four methods with combinations of two reconstruction algorithms and two doses. Results The dose at 10 mA was presumed as 26 mA by SSDE for standard proportion adults. VS, CTDdip, CTDpeak, and LAR with half reconstruction at 10 mA (2.52 ± 0.59, 1.016 ± 0.221, 0.948 ± 0.103, and 0.990 ± 0.527) were similar to those at 240 mA except for VS, and different from those with full reconstruction at both doses (2.24 ± 0.85, 0.830 ± 0.209, 0.986 ± 0.065, and 1.012 ± 0.438 at 240 mA) ( P dip with half reconstruction (–0.024 ± 0.552) at 10 mA was higher compared with full reconstruction (–0.503 ± 0.291) ( P Conclusion PBLC with half reconstruction at 10 mA was comparable to that at 240 mA and better than those with full reconstruction on DVCT.

Arc-welders' pneumoconiosis (AWP) is a less fibrogenic pneumoconiosis with radiographic shadows that can improve after isolation from dusty environments. Therefore, early diagnosis is important. However, the exact role of chest radiograph and computed tomography (CT) for diagnosing AWP is not fully understood. This study was performed to assess the CT appearance of AWP using semi-quantitative methods and to compare the findings with those of silicosis. The profusion of pulmonary abnormality on chest radiograph were also compared with the semi-quantitative CT score.Sixty-six patients with clinically diagnosed AWP were included and compared with 33 patients with silicosis. The CT images were interpreted according to the International Classification of HRCT for Occupational and Environmental Respiratory Diseases (ICOERD). Data on the profusion score by chest radiograph were also compared with CT score.Ill-defined centrilobular nodules, ground-glass opacity (GGO) and centrilobular branching opacity were more frequently observed (p = 0.0031) in AWP, whereas well-defined rounded opacity (p 0.0001), progressive massive fibrosis (p 0.0001), and mediastinal lymphadenopathy (p 0.0001) were more frequently observed in silicosis. Regarding lung nodules, there was a high correlation between the ICOERD and CXR profusion scores in silicosis, but CXR underestimated AWP.Ill-defined centrilobular nodules, GGO and centrilobular branching opacity were more frequently observed in AWP than silicosis. Because these findings are difficult to detect by chest radiograph, CT should be considered for the assessment of patients with suspected AWP.

Rationale and Objectives The objectives of this study were to compare the visibility and quantification of subsolid nodules (SSNs) on computed tomography (CT) using adaptive iterative dose reduction using three-dimensional processing between 7 and 42 mAs and to assess the association of size-specific dose estimate (SSDE) with relative measured value change between 7 and 84 mAs (RMVC7–84) and relative measured value change between 42 and 84 mAs (RMVC42–84). Materials and Methods As a Japanese multicenter research project (Area-detector Computed Tomography for the Investigation of Thoracic Diseases [ACTIve] study), 50 subjects underwent chest CT with 120 kV, 0.35 second per location and three tube currents: 240 mA (84 mAs), 120 mA (42 mAs), and 20 mA (7 mAs). Axial CT images were reconstructed using adaptive iterative dose reduction using three-dimensional processing. SSN visibility was assessed with three grades (1, obscure, to 3, definitely visible) using CT at 84 mAs as reference standard and compared between 7 and 42 mAs using t test. Dimension, mean CT density, and particular SSDE to the nodular center of 71 SSNs and volume of 58 SSNs (diameter >5 mm) were measured. Measured values (MVs) were compared using Wilcoxon signed-rank tests among CTs at three doses. Pearson correlation analyses were performed to assess the association of SSDE with RMVC7–84: 100 × (MV at 7 mAs − MV at 84 mAs)/MV at 84 mAs and RMVC42–84. Results SSN visibilities were similar between 7 and 42 mAs (2.76 ± 0.45 vs 2.78 ± 0.40) (P = .67). For larger SSNs (>8 mm), MVs were similar among CTs at three doses (P > .05). For smaller SSNs ( Conclusions Comparable quantification was demonstrated irrespective of doses for larger SSNs. For smaller SSNs, nodular exaggerating effect associated with decreased SSDE on CT at 7 mAs compared to 84 mAs could result in comparable visibilities to CT at 42 mAs.

We aimed to estimate the usefulness of transcatheter arterial embolization (TAE) in patients with postoperative abdominal hemorrhage and to evaluate the effects of pancreatic fistula on clinical outcomes and angiographic findings. We enrolled 22 patients (20 males and 2 females; mean age 63 years; range 25–86 years), who underwent transarterial angiography for postoperative hemorrhage after abdominal surgery. This group corresponded to 28 procedures. Technical and clinical success rates were calculated, and clinical findings and outcomes were compared between patients with and without a pancreatic fistula. Pre-interventional CT was performed in all patients before first angiography, and the location of the bleeding was identified in all but one patient. Active arterial bleeding, identified by extravasation of contrast agent (n = 12), pseudoaneurysm formation (n = 12), and arterial wall irregularity (n = 2) were detected in 28 angiographic procedures, and embolization was performed in 26 instances. Various embolization techniques such as isolation, packing, embolization, and stentgraft implantation were performed. The technical and clinical success rates were 96% (25/26 procedures) and 82% (18/22 patients), respectively. In hemodynamically unstable patients (shock index: heart rate/systolic blood pressure > 1), a 92% (12/13 cases) technical success rate was achieved. There were no significant differences in any evaluated parameters between patients with and without pancreatic fistula. TAE is a safe and effective for treating postoperative hemorrhage even in patients with hemodynamic instability and pancreatic fistula. Additionally, pre-interventional CT is useful for effective, consecutive interventions.

We aimed to assess and compare ex vivo MRI of resected colorectal carcinoma before and after formalin fixation. We enrolled 45 consecutive patients (47 carcinomas) who underwent colorectal carcinoma surgery. Specimens underwent two MR scans at 1.5 T (after resection and 24 h after formalin fixation). Two radiologists evaluated all MR images independently regarding T-staging and the subserosal linear architecture. T-stage accuracy and frequency of linear architecture were calculated. A third radiologist measured vertical tumor distance and contrast-to-noise ratio (CNR) of the mucosa, submucosa, muscularis propria, subserosa, and tumor. T-stage accuracy compared to histopathology by the two readers was 91.5% and 87.2% before fixation and 91.5% and 85.1% after fixation, respectively. Linear architecture was observed in 11.1% of T2 tumors and 100% of T3 tumors by both readers. The vertical tumor distance between histopathological and MRI findings was well correlated before and after fixation. The measurement error of the vertical tumor distance between before and after fixation was within 3 mm. CNR of the tumor was significantly lower than those of the submucosa and subserosa before and after fixation (p

Purpose To assess the feasibility of Four-Dimensional Ultra-Low-Dose Computed Tomography (4D-ULDCT) for distinguishing pleural aspects with localized pleural adhesion (LPA) from those without. Methods Twenty-seven patients underwent 4D-ULDCT during a single respiration with a 16 cm-coverage of the body axis. The presence and severity of LPA was confirmed by their intraoperative thoracoscopic findings. A point on the pleura and a corresponding point on the outer edge of the costal bone were placed in identical axial planes at end-inspiration. The distance of the two points (PCD), traced by automatic tracking functions respectively, was calculated at each respiratory phase. The maximal and average change amounts in PCD (PCDMCA and PCDACA) were compared among 110 measurement points (MPs) without LPA, 16 MPs with mild LPA and 10 MPs with severe LPA in upper lung field cranial to the bronchial bifurcation (ULF), and 150 MPs without LPA, 17 MPs with mild LPA and 9 MPs with severe LPA in lower lung field caudal to the bronchial bifurcation (LLF) using the Mann-Whitney U test. Results In the LLF, PCDACA as well as PCDMCA demonstrated a significant difference among non-LPA, mild LPA and severe LPA (18.1 ± 9.2, 12.3 ± 6.2 and 5.0 ± 3.3 mm) (p Conclusions Four D-ULDCT could be a useful non-invasive preoperative assessment modality for the detection of the presence or severity of LPA.

Rationale and Objectives This study aimed to compare sub-solid nodule detection performances (SSNDP) on chest computed tomography (CT) with Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR 3D) between 7 mAs (0.21 mSv) and 42 mAs (1.28 mSv) in total and in subgroups classified by nodular size, characteristics, and location, and analyze the association of SSNDP with size-specific dose estimate (SSDE). Materials and Methods As part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases Study, a Japanese multicenter research project, 68 subjects underwent chest CT with 120 kV, 0.35 seconds per rotation, and three tube currents: 240 mA (84 mAs), 120 mA (42 mAs), and 20 mA (7 mAs). The research committee of the study project outlined and approved our study protocols. The institutional review board of each institution approved this study. Axial 2-mm-thick CT images were reconstructed using AIDR 3D. Standard reference was determined by CT images at 84 mAs. Four radiologists recorded SSN presence by continuously distributed rating on CT at 7 mAs and 42 mAs. Receiver operating characteristic analysis was used to evaluate SSNDP at both doses in total and in subgroups classified by nodular longest diameter (LD) (≥5 mm), characteristics (pure and part-solid), and locations (ventral, intermediate, or dorsal; central or peripheral; and upper, middle, or lower). Detection sensitivity was compared among five groups of SSNs classified based on particular SSDE to nodule on CT with AIDR 3D at 7 mAs. Results Twenty-two part-solid and 86 pure SSNs were identified. For larger SSNs (LD ≥ 5 mm) as well as subgroups classified by nodular locations and part-solid nodules, SSNDP was similar in both methods (area under the receiver operating characteristics curve: 0.96 ± 0.02 in CT at 7 mAs and 0.97 ± 0.01 in CT at 42 mAs), with acceptable interobserver agreements in five locations. For larger SSNs (LD ≥ 5 mm), on CT at 42 mAs, no significant differences in detection sensitivity were found among the five groups classified by SSDE, whereas on CT with 7 mAs, four groups with SSDE of 0.65 or higher were superior in detection sensitivity to the other group, with SSDE less than 0.65 mGy. Conclusions For SSNs with 5 mm or more in cases with normal range of body habitus, CT at 7 mAs was demonstrated to have comparable SSNDP to CT at 42 mAs regardless of nodular location and characteristics, and SSDE higher than 0.65 mGy is desirable to obtain sufficient SSNDP.

We investigated the possibility of shortening the time required for loading epirubicin into calibrated polyvinyl alcohol-based hydrogel beads (DC Beads®) to be used for transarterial chemoembolization. After separating the beads suspended in phosphate-buffered saline (PBS) solution by the use of a sieve (clearance 75 µm), epirubicin hydrochloride (EH) was loaded for 20, 30, or 60 s under vibration into DC beads. The EH loading rate into conventionally prepared (control) beads, i.e., beads loaded for 30 min without vibration, and vibration-loaded beads were calculated from the residual EH concentration in the bead-depleted EH solution. The amount of EH eluted from conventionally and vibration-loaded samples into a PBS solution (pH 7.0) was measured at 15 and 30 min and 1, 2, 6, 12, and 24 h. We also recorded the inhibitory effect of the PBS solution on the loading time. Using frozen sections, the EH load in the beads was evaluated visually under a fluorescence microscope. Spectrophotometry (495 nm) showed that the loading rate was 98.98 ± 0.34, 99.02 ± 0.32, and 99.50 ± 0.11 % with 20-, 30-, and 60-s vibration, respectively. The eluted rate was statistically similar between vibration- and statically loaded (control) beads. The PBS solution hampered EH loading into the beads. Visually, the distribution of EH in conventionally and vibration-loaded DC beads was similar. The use of vibration and the removal of PBS solution when epirubicin hydrochloride was loaded into DC beads dramatically shortened the loading time of epirubicin hydrochloride into DC beads.

Introduction The purpose of this study was to evaluate the natural course of the progression of pulmonary subsolid nodules (SSNs). Materials and Methods Eight facilities participated in this study. A total of 795 patients with 1229 SSNs were assessed for the frequency of invasive adenocarcinomas. SSNs were classified into three categories: pure ground-glass nodules (PGGNs), heterogeneous GGNs (HGGNs) (solid component detected only in lung windows), and part-solid nodules. Results The mean prospective follow-up period was 4.3 ± 2.5 years. SSNs were classified at baseline as follows: 1046 PGGNs, 81 HGGNs, and 102 part-solid nodules. Among the 1046 PGGNs, 13 (1.2%) developed into HGGNs and 56 (5.4%) developed into part-solid nodules. Among the 81 HGGNs, 16 (19.8%) developed into part-solid nodules. Thus, the SSNs at the final follow-up were classified as follows: 977 PGGNs, 78 HGGNs, and 174 part-solid nodules. Of the 977 PGGNs, 35 were resected (nine minimally invasive adenocarcinomas [MIAs], 21 adenocarcinomas in situ [AIS], and five atypical adenomatous hyperplasias). Of the 78 HGGNs, seven were resected (five MIAs and two AIS). Of the 174 part-solid nodules, 49 were resected (12 invasive adenocarcinomas, 26 MIAs, 10 AIS, and one adenomatous hyperplasia). For the PGGNs, the mean period until their development into part-solid nodules was 3.8 ± 2.0 years, whereas the mean period for the HGGNs was 2.1 ± 2.3 years ( p = 0.0004). Conclusion This study revealed the frequencies and periods of development from PGGNs and HGGNs into part-solid nodules. Invasive adenocarcinomas were diagnosed only among the part-solid nodules, corresponding to 1% of all 1229 SSNs.

Hideji Otani,1 Tomonori Tanaka,2 Kiyoshi Murata,1 Junya Fukuoka,2 Norihisa Nitta,1 Yukihiro Nagatani,1 Akinaga Sonoda,1 Masashi Takahashi3 1Department of Radiology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu, Shiga, 2Department of Pathology, Nagasaki University Graduate School of Biomedical Sciences, Sakamoto, Nagasaki, 3Department of Radiology, Yujin-Yamazaki Hospital, Takegahana-cho, Hikone, Shiga, Japan Purpose: To evaluate the incidence and pathologic correlation of thin-section computed tomography (TSCT) findings in smoking-related interstitial fibrosis (SRIF) with pulmonary emphysema. Patients and methods: Our study included 172 consecutive patients who underwent TSCT and subsequent lobectomy. TSCT findings including clustered cysts with visible walls (CCVW) and ground-glass attenuation with/without reticulation (GGAR) were evaluated and compared in nonsmokers and smokers and among lung locations. TSCT findings, especially CCVW, were also compared with histological findings using lobectomy specimens. Results: The incidence of CCVW and GGAR was significantly higher in smokers than in nonsmokers (34.1% and 40.7%, respectively, vs 2.0% and 12.2%). CCVW and GGAR were frequently found in the lower and peripheral zones. Histologically, CCVW corresponded more often with SRIF with emphysema than usual interstitial pneumonia (UIP, 63.3% vs 30%). CCVW of irregular size and shape were seen in 19 of 20 SRIF with emphysema and in seven of nine UIP-manifested areas with similar round cysts. A less-involved subpleural parenchyma was observed more frequently in SRIF with emphysema. Conclusion: SRIF with emphysema is a more frequent pathological finding than UIP in patients with CCVW on TSCT. The irregular size and shape of CCVW and a less-involved subpleural parenchyma may be a clue suggesting the presence of SRIF with emphysema. Keywords: pulmonary emphysema, smoking, usual interstitial pneumonia, honeycombing, smoking-related interstitial fibrosis, airspace enlargement with fibrosis

Background Magnetic resonance imaging (MRI) is widely used to diagnose acute abdominal pain; however, it remains unclear which pulse sequence has priority in acute abdominal pain. Purpose To investigate the diagnostic accuracy of MRI and to assess the conspicuity of each pulse sequence for the diagnosis of acute abdominal pain due to gastrointestinal diseases Material and Methods We retrospectively enrolled 60 patients with acute abdominal pain who underwent MRI for axial and coronal T2-weighted (T2W) imaging, fat-suppressed (FS)-T2W imaging, and true-fast imaging with steady-state precession (True-FISP) and axial T1-weighted (T1W) imaging and investigated the diagnosis with endoscopy, surgery, histopathology, computed tomography, and clinical follow-up as standard references. Two radiologists determined the diagnosis with MRI and rated scores of the respective sequences in assessing intraluminal, intramural, and extramural abnormality using a 5-point scale after one month. Diagnostic accuracy was calculated and scores were compared by Wilcoxon-signed rank test with Bonferroni correction. Results Diagnostic accuracy was 90.0% and 93.3% for readers 1 and 2, respectively. Regarding intraluminal abnormality, T2W, FS-T2W, and True-FISP imaging were superior to T1W imaging in both readers. FS-T2W imaging was superior to True-FISP in reader 2 ( P Conclusion T2W and FS-T2W imaging are pivotal pulse sequences and should be obtained before T1W and True-FISP imaging.

Purpose:Dynamic chest radiography (DCR) can observe the dynamic structure of the chest using continuous pulse fluoroscopy irradiation. However, its usefulness remains largely undetermined. The purpose of this study was to examine the relationship between changes in tracheal diameter during deep breathing and obstructive ventilation disorders using DCR., Method:Twelve participants with obstructive ventilatory impairment and 28 with normal pulmonary function underwent DCR during one cycle of deep inspiration and expiration. Three evaluators blinded to pulmonary function test results independently measured lateral diameters of the trachea in DCR images to determine whether there was a difference in the amount of change in tracheal diameter depending on the presence or absence of pulmonary dysfunction. Tracheal narrowing was defined as a decrease in the lateral tracheal diameter of more than 30 %. Participants were divided into a narrowing group and a non-narrowing group, and it was examined whether each group correlated with values of pulmonary function tests., Results:Tracheal diameter was significantly narrowed in subjects with obstructive ventilatory impairment compared to normal subjects (P < 0.01). When subjects were divided into narrowing (tracheal narrowing rate [TNr] = 41.5 ± 7.7 %, n = 9) and non-narrowing groups (TNr = 9.1 ± 7.0 %, n = 31, p < 0.01), FEV1%-G, and %V25 were significantly smaller in the narrowing group than in the non-narrowing group (p < 0.01)., Conclusions:Changes in tracheal diameter during deep breathing were easily evaluated using DCR. DCR may, therefore, be useful for evaluating obstructive ventilation disorders.

To compare sub-solid nodules detectability (SSND) between ultra-low-dose chest digital tomosynthesis (ULD-CDT) with/without iterative reconstruction (IR) and chest radiography (CR) by using low-dose computed tomography (LDCT) as the standard of reference (SOR).Institutional Review Board approved this study and written informed consent was obtained. In a single visit, 79 subjects underwent ULD-CDT at 120 kV and 10 mA, CR and LDCT (effective dose: 0.171, 0.117 and 3.52 mSv, respectively). Sixty-three coronal images were reconstructed using CDT with/without IR. SOR as to SSN presence was determined based on LDCT images. Seven radiologists recorded SSN presence and locations by continuously-distributed rating. Receiver-operating characteristic (ROC) analysis was used to compare SSND of ULD-CDT with/without IR and CR, in total and subgroups classified by nodular longest diameter (LD) (or9 mm) and mean CT attenuation value (CTAV) (or-600 Hounsfield of Unit (HU)). Detection sensitivity (DS) was compared among 4 groups classified by combination of the identical thresholds: nodular LD (9 mm) and mean CTAV (-600 HU) in each of ULD-CDT with/without IR and CR with Friedman and Wilcoxon signed rank test.SSND for total 105 SSNs as well as larger SSNs with nodular LD of 9 mm or more at ULD-CDT with IR was higher than either that at ULD-CDT without IR or CR, as the areas under the ROC curve were 0.66 ± 0.02, 0.59 ± 0.01 and 0.52 ± 0.01, respectively (p 0.05). DS at ULD-CDT with IR was 69.5 ± 10.8% in groups with larger (LD 9 mm) and more-attenuated (-600 HU) SSNs, and higher than in the other 3 groups (p 0.05).ULD-CDT with IR demonstrated better SSND than that without IR or CR, with increased DS for larger and more-attenuated SSNs compared with the remaining ones.

Pleurodesis is frequently performed to prevent recurrence of pneumothorax or recurrent pleural effusion in benign or malignant conditions. In essence, it involves producing an area of adhesion between the parietal and the visceral layers of the pleura. The approach to this procedure can be divided into chemical and mechanical methods. Chemical pleurodesis is performed by introducing various substances such as talc, bleomycin, povidone iodine or other chemicals into the pleural space typically using a pleural catheter. The instilled substances cause inflammation of the parietal and the visceral layers of the pleura and leads to adhesion of the pleural surfaces, preventing further fluid or air accumulation. Mechanical pleurodesis, which is performed with thoracotomy or thoracoscopy, involves mechanical irritation of the pleura or removal of parietal pleura. It is important for the radiologist to develop an understanding of the clinical indications for pleurodesis, methods for the procedure and post-procedure imaging appearance so the radiologist can provide a correct interpretation and avoid misdiagnosis of the radiologic appearance as chronic infection, tumor or other entities with a similar appearance. Thus, the aim of this article is to review the indications, techniques and post-procedural appearances of pleurodesis from an imaging perspective.

To evaluate the effects of adrenal obliteration by balloon-occluded retrograde venous ethanol injection.We inserted a micro-balloon catheter into the left adrenal vein of six pigs and retrogradely injected absolute ethanol (0.06 ml/kg) under balloon occlusion. Two pigs were sacrificed on day 3, 7, and 14 after the procedure, respectively. We evaluated adrenal cortical and medullary hormones of the left renal vein, venograms, magnetic resonance imaging scans obtained before and after the procedure, autopsy and microscopic findings, and the weight of the bilateral adrenal glands.The hormone levels were extremely high on day 3 after the procedure. Post-procedure, partially-enhanced parenchyma and shaggy veins were observed. On the post-mortem examination, the left adrenal glands showed hemorrhage and adhesion on the third and seventh day and fatty proliferation 14 days after the procedure. Microscopic examination revealed hemorrhagic necrosis on day 3, inflammatory cell infiltration on day 7, and partial fibrosis 14 days after the procedure. The weight of the left adrenal gland on day 14 was lower than that of the right gland.This procedure elicited partial adrenal infarction with a high catecholamine concentration in the left renal vein.

To evaluate the embolic effect and degradability of gelatin microspheres (GMS) using various degrees of cross-linkage and particle sizes in rabbit renal artery embolization. Four types of GMS were used, as follows: 2 types of cross-linkage and 2 types of particle size. Twenty-four rabbits (6 in each group) were used for the renal artery embolization. Renal angiography was performed before and after embolization of right renal artery. Follow-up renal angiography was performed 2 days (n = 2), 5 days (n = 2), and 15 days (n = 2) after embolization in each group, and then kidneys were removed for histopathological evaluation. Vascular areas of the angiography were measured by Image J software, and the reperfusion rate was calculated. In renal specimens, residual GMS were checked and the degree of degradation was classified according to a 4-point scale. The mean amounts of large- and small-particle-size GMS injected were 15.0 and 34.3 mg, respectively. Tissue necrosis was confirmed in each group; however, no difference was observed among groups. Renal reperfusion was observed more with small GMS than with large GMS. Renal reperfusion was also observed more with low cross-linked GMS than with high cross-linked GMS. In histopathological specimens, large GMS were confirmed in lobar artery, and small GMS were confirmed in lobular artery. Low cross-linked GMS completely degraded 15 days after embolization. In contrast, high cross-linked GMS were persistent 15 days after embolization. Degree of cross-linkage and particle size affected degradability and reperfusion.

Purpose To evaluate interobserver agreement in regard to measurements of focal ground-glass opacities (GGO) diameters on computed tomography (CT) images to identify increases in the size of GGOs. Materials and Methods Approval by the institutional review board and informed consent by the patients were obtained. Ten GGOs (mean size, 10.4 mm; range, 6.5–15 mm), one each in 10 patients (mean age, 65.9 years; range, 58–78 years), were used to make the diameter measurements. Eleven radiologists independently measured the diameters of the GGOs on a total of 40 thin-section CT images (the first [n = 10], the second [n = 10], and the third [n = 10] follow-up CT examinations and remeasurement of the first [n = 10] follow-up CT examinations) without comparing time-lapse CT images. Interobserver agreement was assessed by means of Bland-Altman plots. Results The smallest range of the 95% limits of interobserver agreement between the members of the 55 pairs of the 11 radiologists in regard to maximal diameter was −1.14 to 1.72 mm, and the largest range was −7.7 to 1.7 mm. The mean value of the lower limit of the 95% limits of agreement was −3.1 ± 1.4 mm, and the mean value of their upper limit was 2.5 ± 1.1 mm. Conclusion When measurements are made by any two radiologists, an increase in the length of the maximal diameter of more than 1.72 mm would be necessary in order to be able to state that the maximal diameter of a particular GGO had actually increased.

Rationale and Objectives To examine the feasibility of quantitative high-resolution computed tomography (HRCT) findings to monitor the stage of bleomycin-induced pulmonary fibrosis in rabbits by correlating HRCT and pathologic scores and analyzing sequential changes on HRCT images using regional volume histograms. Materials and Methods Lung fibrosis was induced by injecting bleomycin intratracheally into 23 Japanese white rabbits. Rabbits were randomly separated into seven groups depending on follow-up period (12-hour, 24-hour, 3-day, 7-day, 14-day, 21-day, and 28-day). Four-row HRCT examinations were performed at any of the seven time points in each follow-up period and just after bleomycin administration in addition to pre-bleomycin administration as the baseline scan. Scores of consolidation, homogenous ground-glass opacity (GGO), inhomogeneous GGO, reticulolinear shadow, and honey-comb formation were recorded as ratio of affected area to total cross-section in four transaxial planes. Inflammatory and fibrous changes were scored histopathologically. Correlations between HRCT and pathologic findings were assessed. Sequential changes on HRCT images in areas with pathologically confirmed fibrosis were assessed on volume histograms of cubic regions of interest (ROI) using quantitative parameters. Results Consolidation and inhomogeneous GGO exhibited fair correlations with inflammation scores ( r = 0.273, P = .009, and r = 0.393, P r = 0.327, P = .001, and r = 0.579, P Conclusion Using appropriate ROI settings, quantitative assessment of inhomogeneous GGO with regional volume histograms enables us to monitor the progression of lung fibrosis by sequential observations.

Rationale and Objectives We used rabbits to investigate the possibility of differentiating between nonalcoholic steatohepatitis (NASH) and fatty liver (FL) on scans acquired by open-type‒ and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)‒enhanced magnetic resonance imaging (MRI). Materials and Methods We divided 15 adult rabbits into three equal groups; they received standard (control group), high-fat (FL) content (FL group), or choline-deficient chow (NASH group). With the animals under general anesthesia we acquired scans on an open 0.3-Tesla MRI system. Signal intensity (SI) was measured before and after contrast administration and defined as SI-pre and SI-post, respectively. Relative SI enhancement (Sr) was calculated using the equation: Sr = (average of three SI-post- minus average of three SI values in no-signal fields)/(average of three SI-pre- minus average of three SI values in no-signal fields) × 100. Maximum Sr (Srmax), the time (in seconds) required to reach Srmax (Tmax), and the difference between Srmax and Sr at 30 minutes (Sr 30m R) were analyzed. Results Srmax was significantly higher in the NASH rabbits than the other two groups ( P Conclusions In rabbits, the Srmax value made it possible to differentiate NASH from normal and fatty liver.

Purpose To compare flat-panel detector (FPD) radiography and film-screen (FS) radiography in detectability of faint shadows documented as ground-glass attenuation (GGA) areas in images of computed tomography (CT). Materials and methods Study population was comprised of 50 patients who underwent FS and another 50 patients who underwent FPD. Standard of reference (SOR) was determined on the basis of area of GGA in all cross-sections of CT, in terms of GGA extent and presence or absence of GGA in each trisected lung fields (GGA distribution). Eight radiologists assessed the GGA extent with the 5-grade scale and the GGA distribution. Inter-observer variances of the GGA extents and distributions, degree of divergences and correspondence in the GGA extent and distributions with SOR, were compared between the FS and FPD by the jackknife method and Fisher's exact test. Results Inter-observer variance in the GGA extent and distribution were slightly larger in the FS than in the FPD. The GGA extent scale corresponded with SOR in the FS statistically significantly better ( p = 0.001), as the correct ratio was 0.428 in the FS and 0.310 in the FPD. Divergence in the GGA extent scale with SOR was smaller in the FS, as average kappa pseudo-value of Kendall's rank correlation coefficient was 0.474 in the FS and 0.433 in the FPD. Conclusion These results indicate that some lesions of GGA documented in CT may not be reflected and are difficult to be detected in chest X-ray radiographs with the FPD.

Rationale and Objectives The aim of this study was to evaluate the usefulness of computer-aided diagnosis (CAD) software for the detection of lung nodules on multidetector-row computed tomography (MDCT) in terms of improvement in radiologists' diagnostic accuracy in detecting lung nodules, using jackknife free-response receiver-operating characteristic (JAFROC) analysis. Materials and Methods Twenty-one patients (6 without and 15 with lung nodules) were selected randomly from 120 consecutive thoracic computed tomographic examinations. The gold standard for the presence or absence of nodules in the observer study was determined by consensus of two radiologists. Six expert radiologists participated in a free-response receiver operating characteristic study for the detection of lung nodules on MDCT, in which cases were interpreted first without and then with the output of CAD software. Radiologists were asked to indicate the locations of lung nodule candidates on the monitor with their confidence ratings for the presence of lung nodules. Results The performance of the CAD software indicated that the sensitivity in detecting lung nodules was 71.4%, with 0.95 false-positive results per case. When radiologists used the CAD software, the average sensitivity improved from 39.5% to 81.0%, with an increase in the average number of false-positive results from 0.14 to 0.89 per case. The average figure-of-merit values for the six radiologists were 0.390 without and 0.845 with the output of the CAD software, and there was a statistically significant difference ( P Conclusion The CAD software for the detection of lung nodules on MDCT has the potential to assist radiologists by increasing their accuracy.

The term ‘emphysema’ is generally used in a morphological sense, and therefore imaging modalities have an important role in diagnosing this disease. In particular, high resolution computed tomography (HRCT) is a reliable tool for demonstrating the pathology of emphysema, even in subtle changes within secondary pulmonary lobules. Generally, pulmonary emphysema is classified into three types related to the lobular anatomy: centrilobular emphysema, panlobular emphysema, and paraseptal emphysema. In this pictorial review, we discuss the radiological – pathological correlation in each type of pulmonary emphysema. HRCT of early centrilobular emphysema shows an evenly distributed centrilobular tiny areas of low attenuation with ill-defined borders. With enlargement of the dilated airspace, the surrounding lung parenchyma is compressed, which enables observation of a clear border between the emphysematous area and the normal lung. Because the disease progresses from the centrilobular portion, normal lung parenchyma in the perilobular portion tends to be preserved, even in a case of far-advanced pulmonary emphysema. In panlobular emphysema, HRCT shows either panlobular low attenuation or ill-defined diffuse low attenuation of the lung. Paraseptal emphysema is characterized by subpleural well-defined cystic spaces. Recent topics related to imaging of pulmonary emphysema will also be discussed, including morphometry of the airway in cases of chronic obstructive pulmonary disease, combined pulmonary fibrosis and pulmonary emphysema, and bronchogenic carcinoma associated with bullous lung disease.

Purpose: To determine the feasibility of assessment of arterial stiffness with multiphase analysis of data sets of retrospectively electrocardiogram (ECG)-gated multidetector row computed tomography (MDCT) coronary angiography by comparing wall stiffness of the descending aorta between patients under chronic hemodialysis and age-matched controls undergoing imaging for by-pass graft. Materials and Methods: We retrospectively assessed 33 patients composed of 10 hemodialysis patients and 23 age-matched control subjects, who underwent MDCT to evaluate the coronary arterial lesions and pulse wave velocity (PWV) measurement. Scan data were reconstructed at 25 phases between 0% and 96% of the R-R intervals with an increment of 4%. Pixel-based measurements of arterial dimensions were performed at 1 cross-section of the descending aorta in a transaxial plane including the aortic valve at its widest. Aortic distensibility (AD) was calculated as follows: AD = (maximal dimension − minimal dimension)/minimal dimension × pulse pressure. Comparison in the AD was performed between the hemodialysis patients and control subjects. Correlation between the AD and PWV were assessed separately in the patients under hemodialysis and age-matched controls. Results: AD was significantly smaller in patients under hemodialysis than in age-matched controls. The square of PWV correlated better with the inverse of the AD in the control subjects compared to patients on hemodialysis. Conclusion: Multiphase analysis in ECG-gated MDCT enables us to assess stiffness of the descending aorta objectively and noninvasively.

The application of metallic stents for benign stenosis is limited due to long-term complications. We report here the results of the implantation of a novel biodegradable poly-L-lactic acid (PLLA) esophageal stent in two patients with benign esophageal stenosis after endoscopic submucosal dissection (ESD). Case 1 was a 64-year-old man who received ESD for an early squamous esophageal cancer in the middle esophagus. The mucosal defect was seven-eighths of the circumference, and the distal margin of the resection scar formed the stenosis. After balloon dilatation, the PLLA esophageal stent was endoscopically placed; for 6 months, he has not experienced any symptoms of re-stenosis. Case 2 consisted of a 62-year-old man who developed an early squamous esophageal cancer in the middle esophagus. The lesion was resected by ESD, and the mucosal defect was seven-eighths of the circumference. The resection scar formed the stenosis, and the PLLA esophageal stent was endoscopically placed. He also has not experienced any symptoms of re-stenosis for 6 months. In conclusion, the PLLA esophageal stent provides a new possibility for the management of benign esophageal strictures after ESD. Due to the biodegradable features of this stent, longer term studies are necessary to investigate the relationship between the expected disappearance of the stent and the patency of the stricture.

To conduct computed tomography (CT)-guided puncture exactly and safely, we newly developed a laser guiding puncture system that can be used in a commercially available CT scanner.The laser-guided CT puncture system is built on the CT table with an aluminum frame. Preliminary simulation tests were conducted using two models representing the body and nodular lesions, and puncture procedures were carried out for 15 patients using this system.The mean distance and standard deviation from the center in simulation experiments conducted using this puncture system were 2.95 +/- 1.20 mm for operator A and 3.52 +/- 1.12 mm for operator B. There was no statistically significant difference between the operators (P = 0.40) or the angles (P = 0.32). For five lung biopsy patients, the distance from the target point planned before biopsy to the actual last puncture point was 0-8 mm. For 10 percutaneous vertebroplasty (PVP) patients (two performed in Th11, one in Th12, five in L1, two in L2), the plan before the puncture procedure was to pass the needle through the vertebral pedicle in all cases. The distance between the planned target point and the actual last puncture point was 0-5 mm.This system has the potential to accomplish the CT-guided puncture procedure safely and accurately.

Background To optimize the image reconstruction phase of multidetector-row computed tomography (MDCT) coronary angiography according to the heart rate is crucial. Methods and Results Scan data were reconstructed for 10 different phases in 58 sequential patients who underwent 8-row cardiac MDCT. The obtained images were scored and compared in terms of motion artifacts and visibility of the vessels, and moreover, ECG record-based evaluations were added for clarification of the temporal relationships among these 10 phases. In the cases with lower heart rates ( 65 beats/min), they were obtained in the late systolic period. Conclusion As the heart rate increased, the optimal image reconstruction phase changed from mid diastole to late systole. However, it is recommended to try to decrease the heart rate of patients before data acquisition. (Circ J 2007; 71: 112 - 121)

Purpose To assess the feasibility of magnetic resonance voiding cystourethrography (MRVCUG) using MR fluoroscopy for evaluation of vesicoureteral reflux (VUR), and its use as a noninvasive alternative to standard VCUG. Materials and Methods A total of 22 MR studies of 16 patients (five months to 41 years old) with primary VUR diagnosed by standard VCUG were evaluated. Six patients underwent MR studies and standard VCUG pre- and postoperatively. MR fluoroscopy was executed with a non-enhanced heavily T2-weighted single-shot fast spin-echo (FSE) sequence. The MR findings were correlated with those obtained by the gold standard, standard VCUG. Results Of the 44 kidney-ureter units, 20 were refluxing on MRVCUG and 21 were refluxing on standard VCUG. There were one false-positive and two false-negative units. MRVCUG was 90% sensitive with a specificity of 96% for detecting VURs that were calculated based on kidney-ureter units. Two false-negative units were found in mild cases (grade I and II). For the units of grade III, IV, and V (high-grade reflux), MRVCUG detected all of the refluxing renal collecting systems. Conclusion MRVCUG can demonstrate high-grade reflux without ionizing radiation or catheterization. J. Magn. Reson. Imaging 2007. © 2006 Wiley-Liss, Inc.

Gadofosveset trisodium is available as a prolonged pooling vascular contrast agent for magnetic resonance imaging. As gadolinium (Gd)-based agents may increase the risk for nephrogenic systemic fibrosis in patients with severe renal insufficiency, the present study synthesized carboxymethyl-diethylaminoethyl dextran magnetite (CMEADM) particles as a blood-pooling, non-Gd‑based contrast agent. CMEADM particles carry a negative or positive charge due to the binding of amino and carboxyl groups to the hydroxyl group of dextran. The present study evaluated whether the degree of charge alters the blood‑pooling time. The evaluation was performed by injecting four groups of three Japanese white rabbits each with CMEADM‑, CMEADM2‑, CMEADM+ (surface charges: ‑10.4, ‑41.0 and +9.6 mV, respectively) or with ultrasmall superparamagnetic iron oxide (USPIO; ‑11.5 mV). The relative signal intensity (SIrel) of each was calculated using the following formula: SIrel = (SI post‑contrast ‑ SI pre‑contrast / SI pre‑contrast) x 100. Following injection with the CMEADMs, but not with USPIO, the in vivo pooling time was prolonged to >300 min. No significant differences were attributable to the electric charge among the CMEADM‑, CMEADM2‑ or and CMEADM+ particles when analyzed with analysis of variance and Tukey's HSD test. Taken together, all three differently‑charged CMEADM2 particles exhibited prolonged vascular enhancing effects, compared with the USPIO. The degree of charge of the contrast agents used in the present study did not result in alteration of the prolonged blood pooling time.

Renal sinus fat (RSF) behaves as one of the perivascular fats, however RSF volume (RSFV) is considerably affected by visceral adipose tissue volume (VTAV). The ratio of RSFV to VATV (RSFV/VATV ratio) can be an index of regional perivascular fat accumulation corrected for the influence of VATV. The aim of this study was to investigate the relation between RSFV/VATV ratio and coronary artery calcium (CAC) in patients with suspected coronary artery disease.One hundred and eighty-nine patients (mean age 66.7 ± 10.2; 72% men) underwent ECG-gated cardiac computed tomography (CT) and unenhanced abdominal CT. CAC score (CACS) was assessed using axial CT images. RSFV was measured by partially manipulated segmentation of the right kidney. VATV was automatically quantified in the upper abdomen. Logistic and correlation analyses were performed to examine the correlations between CAC, RSFV/VATV ratio, and risk factors of cardiovascular diseases in total and subgroups classified by the patients' age.Log-transformed RSFV/VATV ratio was associated with CAC presence in 112 middle-aged patients less than 69 years of age as well as total. This association remained significant after multivariate adjustment only in the middle-aged patients (OR 15.9, 95% CI 1.15-218.8). In total, RSFV/VATV ratio (r = 0.228, p = 0.002) and age (r = 0.316, p0.001) correlated with CACS on univariate analyses, but only age correlated on multivariate analyses. RSFV/VATV ratio correlated with CACS in the middle-aged patients (r = 0.418, p0.001), as well as on multivariate analyses.We demonstrated that RSFV/VATV could be an independent risk indicator of CAC in the middle-aged patients.

PURPOSE Pluronic is a substance that is widely used in medical and pharmaceutical fields. In particular, 20% Pluronic F127 solution is a unique substance that is liquid at less than 15° C and gelatinous at 25 to 60° C. In this study, the authors took advantage of the gelation property of Pluronic F127 at human body temperature to simulate embolization and dissolution of the embolism in the renal artery and the superior mesenteric artery (SMA) using a rabbit model. MATERIALS AND METHODS Four female Japanese rabbits (weight, 2.5-3 kg each) were used. The renal artery was fitted with a 4-F cobra-type catheter and embolized with a 20% Pluronic F127 solution at a temperature of 20° C. The embolic effect was evaluated by angiography immediately after the initial injection and every 15 minutes for 2.5 hours after embolization. After 24 hours, pathologic changes of the renal parenchyma were also evaluated. The embolic effect for SMA and ischemic changes of the intestine were evaluated in the same manner. RESULTS Angiographic findings showed that Pluronic F127 caused embolization immediately after injection and dissolved in the renal artery and the SMA after 90 to 120 minutes. The pathologic findings showed no ischemic change in the renal parenchyma. Necrosis was not found in the intestine, but focal hemorrhagic changes were extensively present when the gel had dissolved. This suggested that Pluronic F127 dissolved before severe tissue damage could occur. CONCLUSION Pluronic F127 can potentially be used as a temporary embolic material.

This paper aims at developing a Computer Aided Diagnosis (CAD) system used for the detection of pulmonary nodules in chest Computed Tomography (CT) images. These lung nodules include both solid nodules and Ground Glass Opacity (GGO) nodules. In our scheme, we apply Gabor filter on the CT image in order to enhance the detection process. After this we perform some morphological operations including threshold process and labeling to extract all the objects inside the lung area. Then, some feature analysis is used to examine these objects to decide which of them are likely to be potential cancer candidates. Following the feature examination, a template matching between the potential cancer candidates and some Gaussian reference models is performed to determine the similarity between them. The algorithm was applied on 715 slices containing 25 GGO nodules and 82 solid nodules and achieved detection sensitivity of 92% for GGO nodules and 95% for solid nodules with False Positive (FP) rate of 0.75 FP/slice for GGO nodules and 2.32 FP/slice for solid nodules. Finally, we used an Artificial Neural Network (ANN) to reduce the number of FP findings. After using ANN, we were able to reduce the FP rate to 0.25 FP/slice for GGO nodules and 1.62 FP/slice for solid nodules but at the expense of detection sensitivity, which became 84 % for GGO nodules and 91% for solid nodules.

To determine the usefulness of newly-proposed index (attenuation-volume index, AVI: increase in mean value of lung attenuation (MVLA) divided by volume decrease ratio (VDR)) for quantitative assessment of lobar air trapping (LAT) using expiratory/inspiratory (E/I) computed tomography (CT) by minimizing influence of respiratory level.Institutional review board approved study protocol. Twenty-one moderate or severe COPD (group A), 16 mild COPD (group B) and 26 normal volunteers (group C) underwent both E/I scans via 320-row CT and pulmonary functional test (PFT). Volume image data were automatically segmented into six lung lobes with minimal manual intervention. AVI, pixel index (PI), air trapping ratio (ATR) and relative volume change (RVC860-950) were calculated in total lung (TL) and each lobe. Four indices in TL were correlated with both PFT result and VDR and those in TL and each lobe were compared between three groups.Similar to ATR, AVI correlated with both FEV1/FVC (r=0.772, p0.01) and RV/TLC (r=-0.726, p0.01) and demonstrated a significant difference between three groups in both TL (group A: 1.69±0.45, group B: 2.21±0.45 and group C: 2.80±0.44) and five lobes except for left lingular segment. In a lobe-based analysis regarding relationship with VDR, AVI was much less dependent than ATR, although regression lines of groups A and C were separated for AVI as well as ATR. Coefficient of variation of either PI or RVC860-950 was significantly larger than that of AVI.AVI can be a more suitable CT index for quantitative evaluation of LAT, minimizing influence of respiratory level.

The diagnostic accuracy of thin-section incremental dynamic computed tomography (IDCT) using an electron-beam scanner in evaluating hilar or mediastinal invasion of bronchogenic carcinoma was assessed. Thirty-seven patients with proven bronchogenic carcinoma, contiguous with hilar or mediastinal structures, underwent IDCT. The area of contact was scanned using 19 contiguous 3-mm thick sections during injection of contrast material. The degree of contact between mass and pulmonary artery or vein and their distortion were recorded. Irregular thickening of the bronchial wall, soft tissue within the lumen, or distortion were used to determine airway involvement. Sixty-nine sites were assessed retrospectively and compared with pathology reports. The accuracy, sensitivity, and specificity in evaluating invasion of the pulmonary artery were 75.0%, 77.8%, and 71.4%, respectively. Limited reliability also was found for invasion of the main bronchus and "secondary" carina, with accuracies of 66.7% and 70.5%, sensitivities of 75.0% and 70.0%, and specificities of 57.1% and 71.4%, respectively. Thin-section IDCT with electron beam scanner is not accurate in the detection of hilar or mediastinal invasion by bronchogenic carcinoma.

We used magnetic resonance imaging (MRI) and histologic techniques to compare the uptake by the rabbit atherosclerotic wall of 4 types of superparamagnetic iron oxide (SPIO) particles, i.e. SPIO, mannan-coated SPIO (M-SPIO), ultrasmall SPIO (USPIO), and mannan-coated USPIO (M-USPIO).All experimental protocols were approved by our institutional animal experimentation committee. We intravenously injected 12 Watanabe heritable hyperlipidemic rabbits with one of the 4 types of SPIO (0.8 mmol Fe/kg). Two other rabbits served as the control. The rabbits underwent in vivo contrast-enhanced magnetic resonance angiography (MRA) before- and 5 days after these injections; excised aortae were subjected to in vitro MRI. In the in vivo and in vitro studies we assessed the signal intensity of the vessels at identical regions of interest (ROI) and calculated the signal-to-noise ratio (SNR). For histologic assessment we evaluated the iron-positive regions in Prussian blue-stained specimens.There were significant differences in iron-positive regions where M-USPIOUSPIO, M-SPIOSPIO, USPIOSPIO (p0.05) but not between M-USPIO and M-SPIO. The difference between the pre- and post-injection SNR was significantly greater in rabbits treated with M-USPIO than USPIO and in rabbits injected with M-SPIO than SPIO (p0.05). On in vitro MRI scans SNR tended to be lower in M-USPIO- and M-SPIO- than USPIO- and SPIO-treated rabbits (p0.1).Histologic and imaging analysis showed that mannan-coated SPIO and USPIO particles were taken up more readily by the atherosclerotic rabbit wall than uncoated SPIO and USPIO.

Our purpose was to investigate the utility of superparamagnetic iron-oxide nanoparticles (SPIO) as a blood-pooling contrast agent at magnetic resonance imaging (MRI). We studied four contrast agents: carboxymethyl-diethylaminoethyl dextran magnetite SPIO (CMEADM-S, diameter 54 nm), negatively charged CMEADM ultrasmall SPIO (CMEADM-U, 32 nm), alkali-treated dextran magnetite SPIO (ATDM-S, 55 nm), and ATDM ultrasmall SPIO (ATDM-U, 28 nm) carrying a neutral charge. Each contrast agent (80 μmol/kg) was injected intraperitoneally into apolipoprotein E (apoE) mice and the tissue iron concentration was measured 30-, 60-, 180-, and 300-min later by nuclear MR. For MR angiographic (MRA) evaluation, we injected the agents into the auricular vein of four groups of 15 rabbits. Immediately and 30-, 60-, 180-, and 300-min later, three rabbits from each group were subjected to MRI. The organ/background signal ratio (SR) was calculated. Statistical analyses were performed with Tukey’s honestly significant difference (HSD) test. At 60 and 180 min, blood-iron concentration of CMEADM-U was significantly different from other contrast agents. In the abdominal aorta and inferior vena cava, SR of CMEADM-U was higher at 180 and 300 min than of the other contrast agents. In the thoracic aorta, there was no difference in SR at 300 min between CMEADM-U and CMEADM-S. Negatively charged SPIO nanoparticles may be useful as a blood-pooling contrast agent.

Keiko Tsuchiya1, Norihisa Nitta1, Akinaga Sonoda1, Ayumi Nitta-Seko1, Shinichi Ohta1, Masashi Takahashi1, Kiyoshi Murata1, Kenichi Mukaisho2, Masashi Shiomi3, Yasuhiko Tabata4, Satoshi Nohara51Department of Radiology, 2Department of Pathology, Shiga University of Medical Science, Otsu, Shiga, 3Institute for Experimental Animals, Kobe University School of Medicine, Kobe, Hyogo, 4Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, 5Nagoya Research Laboratory, Meito Sangyo, Kiyosu, Aichi, JapanAbstract: Magnetic resonance imaging (MRI) can detect atherosclerotic lesions containing accumulations of ultrasmall superparamagnetic iron oxides (USPIO). Positing that improved USPIO with a higher affinity for atherosclerotic plaques would yield better plaque images, we performed MRI and histologic studies to compare the uptake of dextran- and mannan–dextran-coated USPIO (D-USPIO and DM-USPIO, respectively) by the atherosclerotic walls of rabbits. We intravenously injected atherosclerotic rabbits with DM-USPIO (n = 5) or D-USPIO (n = 5). Two rabbits were the controls. The doses delivered were 0.08 (dose 1) (n = 1), 0.4 (dose 2) (n = 1), or 0.8 (dose 3) (n = 3) mmol iron/Kg. The dose 3 rabbits underwent in vivo contrast-enhanced magnetic resonance angiography (MRA) before and 5 days after USPIO administration. Afterwards, all animals were euthanized, the aortae were removed and subjected to in vitro MRI study. The signal-to-noise ratio (SNR) of the aortic wall in the same region of interest (ROI) was calculated in both in vivo and in vitro studies. Histological assessment through measurement of iron-positive regions in Prussian blue-stained specimens showed that iron-positive regions were significantly larger in rabbits injected with DM- rather than D-USPIO (P < 0.05) for all doses. In vivo MRA showed that the SNR-reducing effect of DM- was greater than that of D-USPIO (P < 0.05). With in vitro MRI scans, SNR was significantly lower in rabbits treated with dose 2 of DM-USPIO compared with D-USPIO treatment (P < 0.05), and it tended to be lower at dose 3 (P < 0.1). In conclusion, we suggest that DM-USPIO is superior to D-USPIO for the study of atherosclerotic lesions in rabbits.Keywords: atherosclerosis, magnetic resonance imaging, contrast media, plaque, mannan–dextran-coated USPIO

We report a case of a patient with esophageal squamous cell carcinoma who presented with obstruction of the esophagus. On endoscopy, a central ulcerating lesion was found spreading to the anterior wall of the middle esophagus. Four courses of chemoradiation therapy successfully produced a complete response for 3 years. A recurrence occurred which consisted of a morphologically flat lesion that occupied the entire circumference of the esophagus. Endoscopic submucosal dissection removed all lesions en bloc. To prevent a post-procedure mucosal defect of the circumference of the esophagus, biodegradable poly-l-lactic acid monofilaments esophageal stents were placed on the same day. One month later, the patient reported a feeling of obstruction. An endoscopic examination revealed food stuck in the stents, this was removed, and balloon dilatation provided good passage which has been maintained for 7 months.

Purpose: We followed the 4-week course of implanted VX2 tumors in rabbits and compared MRI and pathological findings to determine the appropriate time for starting therapy in animal liver tumor models. Materials and Methods: We used 18 Japanese white rabbits. The VX2 liver tumor was harvested from one tumor-bearing rabbit and implanted in the liver of the other 17 rabbits. They were then sacrificed at 1 (n = 5), 2 (n = 3), 3 (n = 4), and 4 weeks (n = 5) after implantation and MRI study. Using MRI scans and/or pathological specimens of individual rabbits, we evaluated the tumor survival ratio, the major tumor axes, intrahepatic metastases, and peritoneal dissemination. Results: All tumor transplantations were successful. At 1 week, 56.25% of the implanted tumors were visualized on MRI scans. At 2 weeks or later, all transplanted rabbits were confirmed to be tumor-bearing on MRI scans. At 3 weeks after implantation, the tumor size was similar on MRI scans and in pathological specimens. There were no intra-hepatic metastases or peritoneal disseminations within 2 weeks of tumor transplantation. Conclusion: We suggest that in studies of implanted VX2 models addressing the treatment of solid hepatic tumors, it may be prudent to start hepatic arterial embolization at 2 weeks after implantation.

Regenerative therapy is a new treatment of vascular occlusive diseases. The purpose of this study was to examine the advantages of repeated low-dose growth factor infusions compared with a single high-dose infusion in an ischemic hind-limb rabbit model.Thirty-two rabbits were used to construct an ischemic hind-limb model by resection of the left femoral artery. For the vascular regenerative method, basic fibroblast growth factor (bFGF) was impregnated into 3 mg of gelatin microspheres 30 microm in diameter and a reservoir system was implanted in the left femoral artery for infusion. The gelatin microspheres were then infused into the left internal iliac artery via the reservoir system. The rabbits were divided into three groups according to different infusion methods: single high-dose infusion, repeated low-dose infusions, and saline (control). Therapeutic effects were evaluated by thigh temperature, blood pressure, blood flow, angiography, and pathology.There was no significant difference between the two infusion methods in thigh temperature, blood pressure, blood flow, angiography, and pathology. In pathologic analyses at 2 and 4 weeks, both the repeated low-dose infusion and the single high-dose infusion groups showed significant differences in the number of vessels when compared with the control group.The efficacy of repeated bFGF infusions for neovascularization via the reservoir method was investigated. Despite the pathologic confirmation of neovascularization, there was no significant difference in treatment effect by the two administration methods.

AIM: To report 13 patients with benign esophageal stenosis treated with the biodegradable stent. METHODS: We developed a Ultraflex-type stent by knitting poly-l-lactic acid monofilaments. RESULTS: Two cases were esophageal stenosis caused by drinking of caustic liquid, 4 cases were due to surgical resection of esophageal cancers, and 7 cases were patients with esophageal cancer who received the preventive placement of biodegradable stents for post-endoscopic mucosal dissection (ESD) stenosis. The preventive placement was performed within 2 to 3 d after ESD. In 10 of the 13 cases, spontaneous migration of the stents occurred between 10 to 21 d after placement. In these cases, the migrated stents were excreted with the feces, and no obstructive complications were experienced. In 3 cases, the stents remained at the proper location on d 21 after placement. No symptoms of re-stenosis were observed within the follow-up period of 7 mo to 2 years. Further treatment with balloon dilatation or replacement of the biodegradable stent was not required. CONCLUSION: Biodegradable stents were useful for the treatment of benign esophageal stenosis, particularly for the prevention of post-ESD stenosis.

The aim of this study was to assess quantitatively the impairment of diaphragmatic motion after lung resection, with special reference to the location of the resected lobe, duration of the postoperative period, and patient posture. We used magnetic resonance imaging to make the assessments. In 44 patients (29 men, 15 women; mean age 62.2 years) with lung cancer, diaphragmatic motion was measured during maximum deep, slow breathing using a spoiled gradient-recalled echo sequence before and after lung resection. The study group consisted of 34 patients who were examined using a 1.5-T unit in the supine position and 10 patients using a vertically open 0.5-T unit in both the sitting and supine positions. The influence of surgery site and patient posture on diaphragmatic motion after lung resection was investigated. In all cases after lung resection, diaphragmatic motion on the operated side was significantly decreased (P < 0.001), and that on the nonoperated side was significantly increased (P = 0.045). After left upper lobectomy and right bilobectomy, the diaphragmatic motion on the operated side was significantly decreased (P < 0.001), and that of the other side was significantly increased (P < 0.001). The diaphragmatic motion was not significantly changed after right middle lobectomy. The diaphragmatic motion on the operated side was impaired significantly more (P = 0.035) in the supine position than in the sitting position. After lobe resection, diaphragmatic motion was impaired more significantly in the supine than in the sitting position; and it differed according to the location of the resected lobe. The improvement in diaphragmatic function after lobectomy was observed over a period of 3–24 months.

A novel photosensitizer with magnetic resonance imaging (MRI) activity was designed from fullerene (C(60)) for efficient photodynamic therapy (PDT) of tumor. After chemical conjugation of polyethylene glycol (PEG) to C(60) (C(60)-PEG), diethylenetriaminepentaacetic acid (DTPA) was subsequently introduced to the terminal group of PEG to prepare PEG-conjugated C(60) (C(60)-PEG-DTPA). The C(60)-PEG-DTPA was mixed with gadolinium acetate solution to obtain Gd(3+)-chelated C(60)-PEG (C(60)-PEG-Gd). Following intravenous injection of C(60)-PEG-Gd into tumor-bearing mice, the PDT anti-tumor effect and the MRI tumor imaging were evaluated. The similar O(2)(*-)generation was observed with or without Gd(3+) chelation upon light irradiation. Both of the C(60)-PEG-Gd and Magnevist(R) aqueous solutions exhibited a similar MRI activity. When intravenously injected into tumor-bearing mice, the C(60)-PEG-Gd maintained an enhanced MRI signal at the tumor tissue for a longer time period than Magnevist(R). Injection of C(60)-PEG-Gd plus light irradiation showed significant tumor PDT effect although the effect depended on the timing of light irradiation. The PDT efficacy of C(60)-PEG-Gd was observed at the time when the tumor accumulation was detected by the enhanced intensity of MRI signal. This therapeutic and diagnostic hybrid system is a promising tool to enhance the PDT efficacy for tumor.

RATIONALE AND OBJECTIVES The image quality of a newly developed full-field digital phase contrast mammography (PCM) system and of a conventional screen-film (SF) mammography system were compared via images of a phantom and receiver operating characteristic (ROC) analysis of clinical images. METHODS Magnified (1.75X) PCM images were scanned (sampling rate, 43.75 microm) and then reduced to original-sized, 25-micron pixel images printed on photothermographic film. Along with corresponding SF images, the phantom images were evaluated subjectively, and the clinical images of 38 patients were subjected to ROC analysis of mass and microcalcification. RESULTS In the image quality of a phantom, the PCM exceeded the SF. In both mass and microcalcification, the ROC analysis Az values of the PCM clinical images surpassed those of the SF images. CONCLUSION The PCM provides better images than the SF. Clinical trials suggest superior detection of both mass and microcalcification by full-field digital PCM over conventional SF mammography.

The role of cross-sectional imaging in the diagnosis of Crohn disease has expanded with recent technologic advances in computed tomography (CT) and magnetic resonance (MR) imaging that allow rapid acquisition of high-resolution images of the intestines. To acquire images of diagnostic quality, administration of a fairly large amount of intraluminal contrast agent prior to examination and scanning with intravenous contrast material injection are necessary. Both CT and MR imaging are reported to have a sensitivity of over 95% for the detection of Crohn disease; however, they may not allow early diagnosis. Colonoscopy and conventional enteroclysis studies are indicated for patients with early-stage disease. At more advanced stages, CT and MR imaging can help identify and characterize pathologically altered bowel segments as well as extraluminal lesions (eg, fistulas, abscesses, fibrofatty proliferation, increased vascularity of the vasa recta, mesenteric lymphadenopathy). These modalities can also clearly depict inflammatory lesion activity and conditions that require elective gastrointestinal surgery, thereby aiding in treatment planning. In the clinical setting, CT is currently the imaging modality of choice at most institutions; however, it is expected that MR imaging will soon play a comparable role. CT or MR imaging should be included in a comprehensive evaluation of patients with Crohn disease, along with conventional imaging and clinical and laboratory tests.