Clinical impact of low tube voltage computed tomography during hepatic arteriography with low iodine to detect hepatocellular carcinoma before transarterial chemoembolization.

PURPOSE: This study aimed to evaluate the clinical impact of low tube voltage computed tomography (CT) during hepatic arteriography (CTHA) using low iodine contrast to detect hepatocellular carcinoma (HCC). MATERIALS AND METHODS: CTHA images were obtained using a dual-spin technique (80 kVp and 135 kVp) with 30 ml of low-dose iodine contrast (75 mgI/ml). Three radiologists reviewed 135 kVp and 80 kVp CTHA images to diagnose HCC, recording their confidence scores and evaluations of sharpness, noise, artifact, and overall image quality. Lesion-to-liver contrast ratios and objective noise were measured by a non-reader radiologist. RESULTS: We included 23 patients (body mass index, 23.6 ± 2.6 kg/m2) with 89 HCCs. The mean radiation dose index volume was 21.3 mGy at 135 kVp and 9.4 mGy at 80 kVp (P < 0.001). The overall sensitivity and positive predictive value for diagnosing HCCs at 80 kVp vs. 135 kVp were 0.787 vs. 0.730 and 0.712 vs. 0.756, respectively. The lesion-to-liver contrast ratio at 80 kVp was significantly higher than at 135 kVp in the first (3.1 vs. 2.0; P = 0.008) and second phase (3.1 vs. 2.3; P = 0.016). Objective noise was significantly higher at 80 kVp than at 135 kVp in the first (15. 6 ± 4.9 vs. 11.0 ± 3.1; P < 0.001) and second (16.9 ± 5.2 vs. 15.0 ± 7.3; P = 0.046) phases. CONCLUSION: An 80 kVp CTHA, with lower-dose iodine, improved the sensitivity and reduced the radiation dose, despite a decreased positive predictive value in comparison with a 135-kVp CTHA with the same iodine dose.

18F-fluorodeoxyglucose uptake in advanced gastric cancer correlates with histopathological subtypes and volume of tumor stroma.

PURPOSE: The aim of this study was to investigate the correlation between preoperative 18F-fluorodeoxyglucose (FDG) uptake and histological subtypes, amount of tumor stroma in advanced gastric cancer (GC), and clinical outcomes. METHODS: We evaluated 56 patients (male/female, 42:14; mean age, 69 years) with advanced GC who underwent surgical resection at our institution and positron emission tomography-computed tomography with 18F-FDG prior to surgery. We used the maximum standardized uptake value (SUVmax) of the tumor and the tumor-to-liver ratio (TLR) of the SUVmax for the analysis. The SUVmax and TLR correlated with histological subtypes, immunohistochemistry (IHC) for CD34, and recurrence-free survival (RFS). Tumor stroma in GC was evaluated by CD34 expression. GCs were classified according to the Lauren and World Health Organization (WHO) classifications. RESULTS: The average FDG uptakes (SUVmax) were 4.17% and 14.04% in diffuse and intestinal type GCs, respectively, according to the Lauren classification, and 4.17%, 13.87%, 7.70%, 9.71%, and 19.45% in the poorly cohesive, tubular, mucinous, and papillary adenocarcinomas, respectively, according to the WHO classification. The FDG uptake in diffuse type was significantly lower than that in the intestinal type (p = 0.000). The SUVmax and TLR of the CD34(+) group (mean SUVmax, 5.50; TLR, 1.56) were significantly lower than those of the CD34(-) group (mean SUVmax, 14.09; TLR, 4.09). RFS was not associated with TLR or CD34 expression. CONCLUSION: GC, which has abundant tumor stroma characterized by high CD34 expression on IHC, shows low FDG uptake.

Effect of Portal Vein and Hepatic Artery Occlusion on Radiofrequency Ablation: Animal Experiment Comparing MR and Histology Measurements of the Ablation Zones.

PURPOSE: This animal experimental study evaluated how hepatic artery and portal vein transient occlusion affects the ablation zone of hepatic radiofrequency ablation (RFA). MATERIAL AND METHODS: Twenty-one rabbits were divided into three groups of seven each: (1) control, (2) hepatic artery occlusion, and (3) portal vein occlusion by a balloon catheter. For each rabbit, two or three RFA sessions were performed using an electrode needle. Ablation time, temperature around the tip of RFA needle at the end of RFA, ablation volume on fat-suppressed T1-weighted image in the hepatobiliary phase, and coagulative necrosis area on histopathology were measured and compared between the three groups using the Kruskal-Wallis paired Mann-Whitney U tests. RESULTS: In 43 RFA sessions (group 1, 15; group 2, 14; group 3, 14), mean tissue temperature in group 3 (77.0 °C ± 7.7 °C) was significantly higher compared to groups 1 (59.2 °C ± 18.8 °C; P = 0.010) and 2 (67.5 °C ± 9.9 °C; P = 0.010). In addition, mean ablation volume and coagulative necrosis in group 3 (2.10 ± 1.37 mm3 and 0.86 ± 0.28 mm2, respectively) were larger compared to groups 1 (0.84 ± 0.30 mm3; P < 0.001 and 0.55 ± 0.26 mm2; P = 0.020, respectively) and 2 (0.89 ± 0.59 mm3; P = 0.002 and 0.60 ± 0.22 mm2; P = 0.024, respectively). CONCLUSION: Portal vein occlusion potentially boosts tissue temperature, ablation volume, and area of histopathologically proven coagulative necrosis during hepatic RFA in the non-cirrhotic liver.

Increased 18F-FDG accumulation in less-affected lung area in patients with non-small cell lung cancer and postoperative acute exacerbation of interstitial lung disease.

PURPOSE: To investigate whether or not 18F-FDG accumulation in normal or less-affected lung fields increased in non-small cell lung cancer (NSCLC) patients with postoperative acute exacerbation (PAE) of interstitial lung disease (ILD) MATERIAL AND METHODS: Thirty-six NSCLC patients with ILD and 50 patients without ILD (non-ILD patients) underwent pre-operative 18F-FDG-PET/CT at 2 institutions. Volume-of-interest (VOI) was placed to measure the mean standardized uptake value (SUVmean) in normal or less-affected lung fields at pre-defined 12 areas on ventral and dorsal locations of both lungs. SUVtissue fraction (TF) was defined as corrected SUVmean by using TF and mean computed tomography density on PET/CT. Harmonized SUVmean (hSUVmean) and SUVTF (hSUVTF) were calculated based on results of phantom study, which was performed to optimize the measured SUV difference among 2 institutions. Both the h-SUVmean and the h-SUVTF were compared between 8 patients with PAE of ILD (PAE group) or remaining 28 patients without PAE of ILD (non-PAE group) and non-ILD patients in each of the 12 areas. RESULTS: The hSUVmean in PAE group was higher in 9 out of 12 locations as compared with non-ILD patients, whereas the hSUVmean was mostly similar between non-PAE group and non-ILD patients. In contrast, the hSUVTF in non-PAE group was similar to that in PAE group, and higher than in non-ILD patients in most locations. CONCLUSION: 18F-FDG-PET/CT demonstrated increased SUVmean along with elevated SUVTF in normal or less-affected lung fields for NSCLC patients with PAE of ILD, which may reflect regional invisible fibrosis and inflammatory change.

Usability of the lateral decubitus position on four-dimensional ultra-low-dose computed tomography for the detection of localized pleural adhesion in the pulmonary apical region.

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.

Noncontrast MRI of acute abdominal pain caused by gastrointestinal lesions: indications, protocol, and image interpretation.

Gastrointestinal tract lesions are major causes of acute abdominal pain. A rapid, accurate, and reliable diagnosis is required to manage patients. Magnetic resonance imaging (MRI) is a nonionizing modality that is beneficial for pregnant women, children, and young adults who are sensitive to ionizing radiation. For patients with renal impairment who are not accurately diagnosed with noncontrast computed tomography, noncontrast MRI can serve as an alternative diagnostic modality. MRI protocols used for acute abdominal pain are supposed to be optimized and prioritized to shorten scanning times. Single-shot T2-weighted and fat-suppressed T2-weighted imaging are important pulse sequences that are used to reveal pathology and inflammation in the gastrointestinal tract. Diffusion-weighted imaging clearly depicts inflammation and abscesses as hyperintense lesions. Most acute gastrointestinal tract lesions, including inflammation, ischemia, obstruction, and perforation, demonstrate bowel wall thickening. Bowel obstruction and adynamic ileus present bowel dilatation, and perforation and penetration show bowel wall defects. MRI can be used to reveal these pathological findings with some characteristics depending on their underlying pathophysiology. This review article discusses imaging modalities for acute abdominal pain, describes a noncontrast MRI protocol for acute abdominal pain caused by gastrointestinal tract lesions, and reviews MRI findings of acute gastrointestinal tract lesions.

Preoperative assessment of localized pleural adhesion: Utility of software-assisted analysis on dynamic-ventilation computed tomography.

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 ±â€¯10.7 %) and negative predictive value (NPV) (91.4 ±â€¯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 ±â€¯6.1 %), followed by movie image (58.8 ±â€¯17.0 %) and static image (38.8 ±â€¯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.

Optimization of pulse sequences in ultrafast magnetic resonance imaging for the diagnosis of acute abdominal pain caused by gastrointestinal disease.

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 < 0.0083). For intramural findings, there was no significant difference in reader 1, whereas T2W, FS-T2W, and True-FISP imaging were superior to T1W imaging in reader 2 (P < 0.0083). For extramural findings, FS-T2W imaging was superior to T2W, T1W, and True-FISP imaging in both readers (P < 0.0083). CONCLUSION: T2W and FS-T2W imaging are pivotal pulse sequences and should be obtained before T1W and True-FISP imaging.

A Novel Technique to Predict Liver Damage After Laparoscopic Gastrectomy From the Stomach Volume Overlapping the Liver by Preoperative Computed Tomography.

BACKGROUND: During laparoscopic gastrectomy (LG), it is necessary to manipulate the lateral segment of the liver to secure the surgical field. Liver retraction during surgery often causes liver dysfunction after LG. However, no previous studies have used preoperative image evaluations to predict postoperative liver damage associated with surgical retraction. We aimed to predict postoperative liver damage after LG. METHODS: In all, 117 consecutive patients with gastric cancer who underwent LG were included in this study. Using preoperative computed tomography (CT), the volume of the stomach overlapping the liver was integrated and calculated as the liver projecting stomach volume (LPSV). The liver projection ratio (LPR) was calculated by dividing the LPSV by the volume of the whole stomach. The relationships among liver damage, the LPSV and LPR were evaluated. RESULTS: A total of 112 patients were divided into two groups as follows: 33 patients in the liver dysfunction group (D group) and 79 patients in the non-dysfunction group (N group). The LPSV was significantly larger in the D group than in the N group (median 77.1 vs 50.1 cm3; p = 0.0061). Similarly, LPR values in the D group were significantly higher than those in the N group (median 33.6 vs 26.2%; p = 0.003). Receiver operating characteristic curve analysis indicated a statistically significant ability of the LPSV and LPR to predict postoperative liver damage (area under the curve; 0.705 and 0.735, respectively). Furthermore, multivariate logistic regression analysis revealed that the increase in the LPR was an independent predictor of postoperative liver damage (odds ratio: 1.042; 95% confidence interval: 1.009-1.078; p = 0.019). CONCLUSIONS: We have developed a novel technique for predicting postoperative liver damage associated with surgical liver retraction following LG. This method confirms the degree of the LPSV and LPR of the stomach via preoperative CT.

Difference of computed tomographic characteristic findings between gastric and intestinal gastrointestinal stromal tumors.

PURPOSE: We aimed to compare the computed tomography (CT) imaging differences between gastric and intestinal gastrointestinal stromal tumors (GISTs). MATERIALS AND METHODS: Thirty-eight patients with 38 gastric GISTs and 27 with 31 intestinal GISTs were enrolled. Tumors were classified as small (< 5 cm) or large (≥ 5 cm). Qualitative and quantitative CT imaging characteristics on non-contrast and contrast-enhanced CT were evaluated by two radiologists independently and statistically compared. RESULTS: Early venous return and higher CT number of the draining vein in the arterial phase were more frequent in small-sized intestinal GISTs than in small-sized gastric GISTs (p < 0.001). Small-sized intestinal GISTs demonstrated a wash-out pattern, whereas small-sized gastric GISTs showed a plateau pattern. Contrast enhancement was higher in small-sized intestinal GISTs than in small-sized gastric GISTs (p < 0.001). CT number was inversely proportional to the diameter of intestinal GISTs in both arterial and venous phases but not to that of gastric GISTs. CONCLUSION: Strong enhancement with wash-out pattern and early venous return are characteristic findings of small-sized intestinal GISTs. Radiologists should be aware that CT findings of GISTs have a wide spectrum and may differ according to size and site of origin.

Peripheral bronchial luminal conspicuity on dynamic-ventilation computed tomography: association with radiation doses and temporal resolution by using an ex vivo porcine lung phantom.

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 < 0.05). CCC for CTDdip with half reconstruction (-0.024 ± 0.552) at 10 mA was higher compared with full reconstruction (-0.503 ± 0.291) (P < 0.05). CONCLUSION: PBLC with half reconstruction at 10 mA was comparable to that at 240 mA and better than those with full reconstruction on DVCT.

MR Imaging-based Evaluation of Mesenteric Ischemia Caused by Strangulated Small Bowel Obstruction and Mesenteric Venous Occlusion: An Experimental Study Using Rabbits.

PURPOSE: This study assessed the MRI findings of strangulated small bowel obstruction (SBO) and mesenteric venous occlusion (MVO) in a rabbit model using 3T MRI. MATERIALS AND METHODS: Twenty rabbits were included in this study. The strangulated SBO and MVO models were generated via surgical procedures in nine rabbits, and sham surgery was performed in two rabbits. The success of generating the models was confirmed via angiographic, macroscopic, and microscopic findings after the surgical procedure. MRI was performed before and 30 min after inducing mesenteric ischemia. T1-weighted images (T1WIs), T2-weighted images (T2WIs), and fat-suppressed T2WIs (FS-T2WIs) were obtained using the BLADE technique, and fat-suppressed T1WIs (FS-T1WIs) were obtained. The signal intensities of the affected bowel before and after the surgical procedures were visually categorized as high, iso, and low intense compared with the findings for the normal bowel wall on all sequences. Bowel wall thickness was measured, and the signal intensity ratio (SI ratio) was calculated using the signal intensities of the bowel wall and psoas muscle. RESULTS: Angiographic, macroscopic, and microscopic findings confirmed that all surgical procedures were successful. The ischemic bowel wall was thicker than the normal bowel. The bowel wall was thicker in the MVO model (3.17 ± 0.55 mm) than in the strangulated SBO model (2.26 ± 0.46 mm). The signal intensity and SI ratio of the bowel wall were significantly higher after the procedure than before the procedure on all sequences in both models. The mesentery adjacent to the ischemic bowel loop exhibited a high signal intensity in all animals on FS-T2WIs. CONCLUSION: Non-contrast MRI can be used to evaluate mesenteric ischemia caused by strangulated SBO and MVO. FS-T2WIs represented the best modality for depicting the high signal intensity in the bowel wall and mesentery caused by ischemia.

Management of acute cholecystitis after biliary stenting for malignant obstruction: comparison of percutaneous gallbladder drainage and aspiration.

PURPOSE: To evaluate and compare the clinical outcomes between percutaneous gallbladder drainage (PGBD) and percutaneous gallbladder aspiration (PGBA) for acute cholecystitis after biliary stenting for malignant biliary obstruction. MATERIALS AND METHODS: Twenty-six and 14 patients underwent PGBD and PGBA, respectively, for acute cholecystitis after biliary stenting for malignant obstruction. The technical success rate, clinical effectiveness, and safety were compared between the 2 groups. RESULTS: Technical success was achieved in all patients. Clinical effectiveness rate was significantly higher in the PGBD group than in the PGBA group [100% (26/26) vs. 57% (8/14), p < 0.01]. In the PGBA group, clinical effectiveness rate was significantly lower in patients with tumor involvement of the cystic duct [13% (1/8) with involvement vs. 83% (5/6) without involvement, p = 0.03]. There were no deaths related to the procedure or acute cholecystitis aggravation. Pleural effusion and biliary peritonitis occurred in 1 patient each after PGBD and intra-abdominal bleeding occurred in 1 patient after PGBA as complications requiring treatment. CONCLUSION: Although PGBD was a more effective treatment for acute cholecystitis after biliary stenting for malignant obstruction, PGBA may be a less invasive option for high-risk patients without tumor involvement of the cystic duct.

Change in hepatic hemodynamics assessed by hepatic arterial blood pressure and computed tomography during hepatic angiography with the double balloon technique.

PURPOSE: To assess the change in hepatic arterial blood pressure (HABP) and computed tomography during hepatic arteriography (CTHA) using the double balloon technique. MATERIALS AND METHODS: Nine patients with hepatocellular carcinoma (HCC) were enrolled. We inserted a 5.2-Fr balloon catheter into the common or proper hepatic artery and a 1.8-Fr microballoon catheter into the lobar or segmental artery feeding the HCC. HABPs were measured with the 1.8-Fr microballoon catheter (usual-HABP), with the 1.8-Fr balloon inflated (B-HABP), and with both the 5.2-Fr and 1.8-Fr balloons inflated (BB-HABP). CTHAs were performed via a 1.8-Fr microcatheter (usual-CTHA), with the 1.8-Fr balloon inflated (B-CTHA selective), with both the 5.2-Fr and 1.8-Fr balloons inflated (BB-CTHA selective), and via the 5.2-Fr catheter with the 1.8-Fr balloon inflated (B-CTHA whole) and with both the 5.2-Fr and 1.8-Fr balloons inflated (BB-CTHA whole). RESULTS: In all cases, B-HABP was lower than usual-HABP. There was a decrease in BB-HABP in comparison with B-HABP in cases with occlusion of the proper hepatic artery. The contrast effect of B-CTHA selective increased in four cases. The contrast effect on B-CTHA whole remained in all cases. CONCLUSION: This technique can be useful in decreasing HABP and collateral blood flow from the adjacent hepatic segment.

Comparison of characteristic computed tomographic findings of gastrointestinal and non-gastrointestinal stromal tumors in the small intestine.

PURPOSE: 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. METHODS: 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. RESULTS: 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 < 0.001). The CT value of the solid tumor part in the arterial and venous phases (p < 0.01) and the CT value of the drainage vein in the arterial phase (p < 0.05) were higher for GISTs than for non-GISTs (p < 0.01). CONCLUSIONS: Strong parenchymal enhancement with the peak in the arterial phase and the CT value of the drainage vein in the arterial phase was characteristics findings of GIST compared with non-GISTs. The diameter of the drainage vein was proportional to the maximum diameter of GISTs.

Continuous quantitative measurement of the main bronchial dimensions and lung density in the lateral position by four-dimensional dynamic-ventilation CT in smokers and COPD patients.

PURPOSE: The purpose of this study was to measure changes in lung density and airway dimension in smokers in the lateral position using four-dimensional dynamic-ventilation computed tomography (CT) during free breathing and to evaluate their correlations with spirometric values. MATERIALS AND METHODS: Preoperative pleural adhesion assessments included dynamic-ventilation CT of 42 smokers (including 22 patients with COPD) in the lateral position, with the unoperated lung beneath (dependent lung). The scanned lungs' mean lung density (MLD) and the bilateral main bronchi's luminal areas (Ai) were measured automatically (13-18 continuous image frames, 0.35 seconds/frame). Calculations included cross-correlation coefficients (CCCs) between the MLD and Ai time curves, and correlations between the quantitative measurements and spirometric values were evaluated by using Spearman's rank coefficient. RESULTS: The ΔMLD1.05 (from the peak inspiration frame to the third expiratory frame, 1.05 seconds later) in the nondependent lung negatively correlated with FEV1/FVC (r=-0.417, P<0.01), suggesting that large expiratory movement of the nondependent lung would compensate limited expiratory movement of the dependent lung due to COPD. The ΔAi1.05 negatively correlated with the FEV1/FVC predicted in both the lungs (r=-0.465 and -0.311, P<0.05), suggesting that early expiratory collapses of the main bronchi indicate severe airflow limitation. The CCC correlated with FEV1/FVC in the dependent lung (r=-0.474, P<0.01), suggesting that reduced synchrony between the proximal airway and lung occurs in patients with severe airflow limitation. CONCLUSION: In COPD patients, in the lateral position, the following abnormal dynamic-ventilation CT findings are associated with airflow limitation: enhanced complementary ventilation in the nondependent lung, early expiratory airway collapses, and reduced synchrony between airway and lung movements in the dependent lung.

Sub-solid nodule detectability in seven observers of seventy-nine clinical cases: comparison between ultra-low-dose chest digital tomosynthesis with iterative reconstruction and chest radiography by receiver-operating characteristics analysis.

PURPOSE: 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). MATERIALS AND METHODS: 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) (> or < 9 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. RESULTS: 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). CONCLUSION: 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.

Transcatheter Arterial Embolization for Postoperative Bleeding Following Abdominal Surgery.

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Ex vivo MR imaging of colorectal carcinoma before and after formalin fixation: correlation with histopathologic findings.

PURPOSE: We aimed to assess and compare ex vivo MRI of resected colorectal carcinoma before and after formalin fixation. METHODS: 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. RESULTS: 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 < 0.05). CNRs of the tumor and muscularis propria were decreased after formalin fixation (p < 0.05). CONCLUSIONS: Subserosal linear architecture represented fibrosis with tumoral invasion, suggesting a T3-4 tumor. The submucosa and subserosa showed high intensity and the mucosa and muscularis propria showed low intensity compared with tumor. CNRs of the tumor and muscularis propria were decreased by formalin fixation.