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Biomedical subjects

Kyoung Ho Lee

Publications and source records attributed to Kyoung Ho Lee.

At least 19 recordsLinked to original sources

Irreversible JPEG 2000 compression of abdominal CT for primary interpretation: assessment of visually lossless threshold.

To estimate the visually lossless threshold for Joint Photographic Experts Group (JPEG) 2000 compression of contrast-enhanced abdominal computed tomography (CT) images, 100 images were compressed to four different levels: a reversible (as negative control) and irreversible 5:1, 10:1, and 15:1. By alternately displaying the original and the compressed image on the same monitor, six radiologists independently determined if the compressed image was distinguishable from the original image. For each reader, we compared the proportion of the compressed images being rated distinguishable from the original images between the reversible compression and each of the three irreversible compressions using the exact test for paired proportions. For each reader, the proportion was not significantly different between the reversible (0-1%, 0/100 to 1/100) and irreversible 5:1 compression (0-3%). However, the proportion significantly increased with the irreversible 10:1 (95-99%) and 15:1 compressions (100%) versus reversible compression in all readers (P < 0.001); 100 and 95% of the 5:1 compressed images were rated indistinguishable from the original images by at least five of the six readers and all readers, respectively. Irreversibly 5:1 compressed abdominal CT images are visually lossless and, therefore, potentially acceptable for primary interpretation.

Contrast Media↗

Hepatic macrosteatosis: predicting appropriateness of liver donation by using MR imaging--correlation with histopathologic findings.

PURPOSE: To retrospectively evaluate the diagnostic performance of magnetic resonance (MR) imaging in predicting the appropriateness of liver donation in potential living liver donors by using histopathologic results as the reference standard. MATERIALS AND METHODS: This study was approved by institutional review board; all patients gave informed consent for the use of MR data for future research. Fifty-seven potential liver donors (40 male, 17 female; age range, 17-57 years; mean age, 32 years) underwent dual-echo 1.5-T MR imaging. Two radiologists qualitatively graded each MR image, with consensus for disagreements. Livers were assigned one of three degrees of hepatic steatosis on the basis of changes in hepatic signal intensity (SI) between in-phase and opposed-phase images. For quantitative analysis, a third radiologist calculated mean hepatic and mean splenic SI by averaging 25 hepatic regions of interest and three splenic regions of interest. Relative SI decrease (RSID) in the liver on opposed-phase images compared with in-phase images was calculated. Linear regression analysis was used to correlate RSID with the degree of total steatosis, macrosteatosis, and microsteatosis. Diagnostic performance for predicting the appropriateness of liver donation was analyzed. RESULTS: Histologic findings of macrosteatosis resulted in 52 patients being categorized as appropriate donors, with the remaining five being categorized as inappropriate donors. RSID was correlated with total steatosis (r = 0.850). When the RSID criterion for inappropriateness of liver donation was set at 20%, the sensitivity, specificity, and accuracy were 100%, 92.3%, and 93%, respectively. When RSID was used, four livers that had been misclassified as inappropriate for transplantation were found to have microsteatosis of various degrees and a less than moderate degree of macrosteatosis at histologic analysis. Qualitative and quantitative analyses were comparably accurate. CONCLUSION: When an RSID criterion of less than 20% was used, dual-echo MR imaging facilitated the correct prediction of appropriateness of liver donation in 53 of 57 patients.

Adolescent↗

Percutaneous drainage of postoperative abdominal abscess with limited accessibility: preexisting surgical drains as alternative access route.

PURPOSE: To retrospectively assess the effectiveness and safety of postoperative percutaneous drainage of abdominal abscesses with limited accessibility by using a preexisting surgical drain as an access route. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was not required. The authors reviewed the medical records of 92 patients (62 male, 30 female; median age, 59 years; age range, 3-79 years) with postoperative abdominal abscesses in whom percutaneous drainage was performed by using surgical drains as an access. Factors evaluated included the location and size of the lesion; time between surgery and the drainage procedure; distance between the lesion and surgical drain; presence of fistula; duration of drainage; type of surgical drain; size, type, and length of drainage catheter; and complications. Technical success was defined as adequate placement of a new drainage catheter into the target abscess. Midterm success was defined as avoidance of surgery or additional percutaneous drainage during the 6 months of follow-up. Univariate analysis and multiple logistic regression analysis were performed to determine factors that affected the technical or midterm success of the procedure. RESULTS: Of 92 postoperative abscesses for which the technique was attempted, 56 (61%) had a subphrenic location and 36 (39%) had a peripancreatic location. Technical success was achieved in 87 of the 92 patients (95%). Technical success was not significantly associated with any of the factors tested. Midterm success was achieved in 75 of the 87 patients (86%) in whom technical success was achieved. Midterm failure showed a statistically significant relationship with the presence of fistula (P = .04). No procedure-related complications were identified. CONCLUSION: Percutaneous drainage by using the surgical drain as an access route is an effective and safe alternative for draining postoperative abdominal abscesses that are less accessible with direct puncture..

Abdominal Abscess↗

Computed tomography diagnosis of acute appendicitis: advantages of reviewing thin-section datasets using sliding slab average intensity projection technique.

OBJECTIVES: We sought to compare sliding slab mode and standard stack mode in the computed tomography (CT) diagnosis of acute appendicitis. MATERIALS AND METHODS: Contrast-enhanced CT was performed in 85 patients, 35 of whom had appendicitis. Four readers retrospectively reviewed 5-mm thick transverse sections (4-mm increment) using the stack mode and 2-mm thick sections (1-mm increment) with the sliding slab, average intensity projection. The sliding slab mode started with a 5-mm thick transverse slab, but the readers were encouraged to change the viewing angle and the slab thickness. RESULTS: In sliding slab mode, the readers changed the viewing angle in 89 of 340 observations (24%) and decreased the slab thickness in 26 observations (8%). Although the receiver operating characteristic analysis did not show a significant difference (P = 0.18), the sliding slab mode enhanced the pooled sensitivity (93.6% vs. 98.6%, P = 0.02), specificity (92.0% vs. 97.5%, P = 0.01), and mean confidence for the diagnosis (P < 0.001) or exclusion (P = 0.002) of acute appendicitis; reduced inconclusive interpretations (5.6% vs. 1.8%, P = 0.01); and visualized the appendix more clearly (P < 0.001). CONCLUSIONS: Compared with the stack mode, the sliding slab mode enhances diagnostic confidence and more clearly visualizes the appendix.

Acute Disease↗

CT Differentiation of cholangiocarcinoma from periductal fibrosis in patients with hepatolithiasis.

OBJECTIVE: The objective of our study was to determine useful CT findings for differentiating cholangiocarcinoma from periductal fibrosis in patients with hepatolithiasis. MATERIALS AND METHODS: CT images of 30 patients with hepatolithiasis and pathologically proven cholangiocarcinoma (n = 14) or periductal fibrosis (n = 16) were retrospectively reviewed. Helical CT scans were obtained before, 30 seconds after, and 65 seconds after the start of contrast material injection. Analysis of CT findings included evaluation for the presence of periductal soft-tissue density, bile duct wall thickening at the stricture site, ascites, portal vein obliteration, lymph node enlargement, and a duct stone; assessment of the degree of ductal dilatation; and evaluation of the enhancement pattern of periductal lesions, thickened ductal wall, and hepatic parenchyma. The CT attenuation coefficients of the thickened ductal wall and adjacent normal-looking bile duct were measured on images obtained during each phase. Among these findings, statistically significant variables were determined using the Fisher's exact test and Student's t test. Sensitivity and specificity values of the CT criteria were also calculated. RESULTS: The presence of periductal soft-tissue density (p = 0.002), higher enhancement of the duct than adjacent bile duct on portal venous phase images (p = 0.008), ductal wall thickening (p = 0.026), portal vein obliteration (p = 0.031), and lymph node enlargement (p = 0.031) were found to be the significant findings for differentiating cholangiocarcinoma from fibrosis in patients with hepatolithiasis. When any two or more of these five criteria were used in combination, we could identify 100% of the patients with cholangiocarcinoma but only 12.5% of the patients with fibrosis. CONCLUSION: Cholangiocarcinoma in patients with hepatolithiasis can be diagnosed using specific CT criteria.

Aged↗

Small-bowel obstruction in a phantom model of ex vivo porcine intestine: comparison of PACS stack and tile modes for CT interpretation.

PURPOSE: To compare computed tomographic (CT) image interpretation with picture archiving and communication systems (PACS) stack and tile modes for speed and accuracy of transition zone localization in small-bowel obstruction by using ex vivo porcine specimens. MATERIALS AND METHODS: Twenty-five small-bowel obstruction phantom models made of ex vivo porcine intestines from a slaughterhouse were imaged at CT. One was used for observer training, and 24 were used for experimentation. At 20-cm intervals throughout the intestines, metallic markers were placed in the mesenteries immediately adjacent to bowel. One obstruction was made in each intestine, midway between markers, by ligating intestine with a 3-0 silk suture to simulate mechanical small-bowel obstruction. The lumen proximal to the ligation site was distended with air and a soybean oil-iodized oil mixture until at least two-thirds of the proximal intestine exceeded 2.0 cm in transverse diameter. Dilated segments were 310-550 cm in length. Soybean oil and a mixture of soybean and iodized oil were used to simulate differences in attenuation among bowel wall, intraluminal fluid, and extraluminal abdominal fat. Four experienced abdominal radiologists independently determined the transition zone by using stack mode (cine viewing of stacked images) and, at least 2 weeks later, tile mode (side-by-side image display). Accuracy and degree of error in counting markers were evaluated, and speed of interpretation was recorded. Statistical analysis was performed with the McNemar and Wilcoxon signed rank tests. RESULTS: For all observers, accuracy of transition zone localization tended to be better with stack mode (63%-83% [15-20 phantoms]) than with tile mode (50%-63% [12-15 phantoms]), but the differences were not significant. For each observer, mean counting error was lower in stack mode (range, 0.96-2.48) than in tile mode (range, 1.74-3.22), with significance for three observers (P < .01, P < .01, and P = .04). Interpretation was significantly faster with stack mode by a factor of two to three for all observers (P < .01). CONCLUSION: Stack mode evaluation for identification of the transition zone in obstructed small bowel is faster than evaluation with tile mode. Accuracy is not significantly different between modes, although there is a tendency toward better results with stack mode.

Animals↗

Differentiating malignant from benign common bile duct stricture with multiphasic helical CT.

PURPOSE: To evaluate retrospectively the use of multiphasic helical computed tomography (CT) to differentiate malignant and benign common bile duct (CBD) strictures in patients with only a focal CBD stricture and to determine predictors for this differentiation. MATERIALS AND METHODS: Institutional review board approval and informed patient consent were not required. Fifty patients (35 men, 15 women; age range, 35-87 years; mean age, 61.6 years) with only a focal CBD stricture comprised the sample for this study (32 malignant and 18 benign strictures). The diagnosis of all malignant and five benign CBD strictures was confirmed by reviewing patients' surgical and pathology records; in 13 benign CBD strictures, the diagnosis was confirmed by means of clinical features. Multiphasic CT findings were analyzed with regard to the wall thickness, location, length, and enhancement pattern of the involved CBD, the upstream CBD diameter, and other findings. CT features to identify benign and malignant CBD strictures were compared by means of univariate analysis and multivariable stepwise logistic regression analysis. RESULTS: Malignant strictures were longer (17.9 mm +/- 6.6 [+/- standard deviation]) than benign strictures (8.9 mm +/- 6.8) (P < .0001), and upstream CBD diameters were larger in malignant cases (22.0 mm +/- 5.4) than in benign cases (17.8 mm +/- 4.6) (P = .033). The involved wall thickness was more than 1.5 mm in 26 malignant cases and three benign cases (P < .0001). During both hepatic arterial and portal venous phases, greater enhancement than that in the normal CBD were more frequently observed in malignant cases (in 27 and 30 patients for hepatic arterial and portal venous phase scans, respectively) than in benign cases (in two and three patients, respectively) (P < .0001). Results of multivariable stepwise logistic regression analysis showed that hyperenhancement of the involved CBD during the portal venous phase was the only variable that could be used to independently differentiate malignant from benign strictures. CONCLUSION: Hyperenhancement of the involved CBD during the portal venous phase is the main factor distinguishing malignant from benign CBD strictures.

Adult↗

Squalene aspiration pneumonia in children: radiographic and CT findings as the first clue to diagnosis.

BACKGROUND: The diagnosis of squalene aspiration pneumonia in children is often difficult because of minimal non-specific symptoms. OBJECTIVE: To investigate the radiological findings of squalene aspiration pneumonia in children. MATERIALS AND METHODS: We reviewed the chest radiographs (n = 8) and CT scans (n = 7), including high-resolution CT (n = 3), of eight patients (four boys, four girls; age 3 months to 6 years) with squalene aspiration pneumonia. All patients presented minimal symptoms. RESULTS: Chest radiographs showed right-sided predominantly parahilar infiltrations. The extent and the opacity of the lesions decreased slowly during the follow-up period (mean 5.4 months) after halting the exposure. On CT, affected areas appeared as dense consolidations surrounded by ground-glass opacities showing a crazy-paving pattern in a geographic lobular distribution in all patients. The lesions were predominantly in the right lung and dependent areas in all patients and extensively involved all pulmonary lobes in five patients. CONCLUSIONS: These radiological findings, although non-specific, can lead to an appropriate diagnosis, particularly when patients present few symptoms.

Child↗

Appropriateness of a donor liver with respect to macrosteatosis: application of artificial neural networks to US images--initial experience.

PURPOSE: To retrospectively compare performance of artificial neural networks (ANNs) applied to ultrasonographic (US) images with that of radiologists for prediction of appropriateness of a donor liver with respect to macrosteatosis before liver transplantation. MATERIALS AND METHODS: Institutional ethics committee approved study; written informed consent was obtained. ANNs, constructed with three-layered 15-neuron back-propagation algorithm, were trained to predict appropriateness of a donor liver with respect to macrosteatosis by using statistically significant laboratory and US parameters derived from univariate analyses, together with correct diagnosis. Input variables for ANNs were alkaline phosphatase, glutamic oxaloacetic transaminase, glutamic pyruvate transaminase, gamma-glutamyltransferase, hepatorenal ratio of echogenicity, and tail area ratio and tail length of portal vein wall echogenicity. Three radiologists graded US images in 94 potential donors (71 men and 23 women) on the basis of four degrees of hepatic steatosis. After training and testing of ANNs, performance of ANNs and radiologists in predicting appropriateness of potential donors was evaluated with receiver operating characteristic (ROC) analysis and compared by means of univariate z score test. RESULTS: Among 94 potential donor livers, 76 were normal or had mild steatosis, and 18 had moderate or severe macrosteatosis at histopathologic examination. Area under ROC curve (Az) of ANNs (Az=0.9673) was significantly greater than that of radiologists (faculty, Az=0.9106, P=.048; fellow, Az= 0.9038, P=.044; resident, Az=0.8931, P=.038). No statistically significant difference in sensitivity for predicting appropriateness as a liver donor with respect to macrosteatosis was found between ANNs (88.9%) and radiologists (P >.05). However, specificity of ANNs (96.1%) was significantly better than that of radiologists (P <.003). CONCLUSION: ANNs might be a useful tool to categorize whether a donor liver is appropriate for transplantation with respect to macrosteatosis on the basis of multiple variables related to laboratory and US features. Further study is needed.

Adolescent↗

Managing the CT data explosion: initial experiences of archiving volumetric datasets in a mini-PACS.

Two image datasets (one thick section dataset and another volumetric dataset) were typically reconstructed from each single CT projection data. The volumetric dataset was stored in a mini-PACS with 271-Gb online and 680-Gb nearline storage and routed to radiologists' workstations, whereas the thick section dataset was stored in the main PACS. Over a 5-month sample period, 278 Gb of CT data (8976 examinations) was stored in the main PACS, and 738 Gb of volumetric datasets (6193 examinations) was stored in the mini-PACS. The volumetric datasets formed 32.8% of total data for all modalities (2.20 Tb) in the main PACS and mini-PACS combined. At the end of this period, the volumetric datasets of 1892 and 5162 examinations were kept online and nearline, respectively. Mini-PACS offers an effective method of archiving every volumetric dataset and delivering it to radiologists.

Database Management Systems↗

In vitro CT evaluation of intrahepatic stones: correlation with chemical composition.

OBJECTIVE: To describe in vitro CT features of intrahepatic stones and to correlate CT attenuation with chemical composition. MATERIALS AND METHODS: Of the patients who underwent choledochoscopic intrahepatic stone removal between 1998 and 2001, 54 patients with stones larger than 3 mm were enrolled in this study. In each case, a chemical compositional analysis was performed to determine calcium, cholesterol, total bilirubin, and inorganic phosphorus compositions. The three largest stones obtained from each patient were imaged by CT. CT attenuation numbers were measured in the center images of each stone by drawing free-hand region of interest (ROI). The measured CT attenuation numbers were correlated with their chemical composition. Also, CT attenuation numbers of stones were compared with that of the liver on non-contrast CT (50-70 HU). RESULTS: Stone size ranged from 3.1 to 10.5 mm (mean +/- S.D.: 6.0 +/- 1.4). The CT attenuation numbers (HU) of stones ranged from 36.4 to 410.19 (mean +/- S.D.: 94.6 +/- 49.9). CT numbers of stones were below 70 HU in 11 patients (20.4%), and below 90 HU in 33 patients (59.3%). The chemical analysis data of the stones were as follows: calcium (0.5-6.5 wt.%; mean +/- S.D., 2.6 +/- 1.4), total bilirubin (0.45-24.4 wt.%; 13.1 +/- 6.2), cholesterol (5.4-73.9 wt.%; 29.3 +/- 17.4), phosphorus (0.1-1.2 wt.%; 0.6 +/- 0.3), and non-soluble residue (17.6-85.4 wt.%; 57.0 +/- 22.6). There was a weak but significant correlation between calcium composition and CT attenuation (r = 0.38, P < 0.01) and no significant correlation between other chemical compositions and the CT attenuation (cholesterol, r = 0.01, P > 0.01; total bilirubin, r = 0.05, P > 0.01; phosphorus, r = 0.01, P > 0.01). CONCLUSION: On non-contrast CT, intrahepatic stones would not be hyperattenuating with respect to liver parenchyma in about one fifth of patients. The CT attenuation of stones correlates with calcium and does not correlate with any other chemical composition.

Adult↗

Hepatic attenuation differences associated with obstruction of the portal or hepatic veins in patients with hepatic abscess.

OBJECTIVE: The purpose of our study was to determine the nature of the association between the attenuation difference of the hepatic parenchyma surrounding an abscess and obstruction of the regional portal vein or of the hepatic vein. MATERIALS AND METHODS: Helical CT scans of 60 patients with hepatic abscess were analyzed for the presence of complete or partial obstruction of the portal or hepatic veins and for attenuation differences in the surrounding parenchyma. Clinical (age, sex, underlying disease, and microorganism) and CT (obstruction of the portal or hepatic vein and number, location, and size of abscesses) findings were analyzed statistically for possible associations with each of regional parenchymal hyper- and hypoattenuation by using the chi-square test and multivariate logistic regression analysis. RESULTS: Regional parenchymal hyperattenuation was identified in 40 patients (67%). More patients with portal vein obstruction showed regional parenchymal hyperattenuation than patients without portal vein obstruction (22/27 patients vs 18/33, p = 0.028), and more patients with hepatic vein obstruction showed regional parenchymal hypoattenuation than those without hepatic vein obstruction (11/21 vs 3/39, p = 0.0003). Multivariate logistic regression analysis showed that portal venous obstruction was the only statistically significant predictor of regional parenchymal hyperattenuation (p = 0.032; odds ratio, 3.7) and that parenchymal hypoattenuation was associated with hepatic venous obstruction (p = 0.001; odds ratio, 44.9). CONCLUSION: Parenchymal hypo- and hyperattenuation are frequently observed in the hepatic region surrounding an abscess on dynamic CT. Moreover, these parenchymal attenuation differences are associated with regional portal or hepatic vein obstruction.

Adult↗

Postbiopsy splenic bleeding in a dog model: comparison of cauterization, embolization, and plugging of the needle tract.

OBJECTIVE: The purpose of our study was to compare radiofrequency cauterization, embolization using an absorbable gelatin sponge, and a Histoacryl-Lipiodol mixture plugging as postbiopsy bleeding reduction methods after splenic core needle biopsy in a dog model. MATERIALS AND METHODS: Eleven mongrel dogs were randomly separated into nonheparinized (n = 5) and heparinized (n = 6) groups. Eight splenic biopsies per animal were performed using an 18-gauge automated core biopsy needle: two as controls, two ablated by radiofrequency, two embolized using an absorbable gelatin sponge, and two plugged using a Histoacryl-Lipiodol mixture. Procedure times and postbiopsy bleeding amounts were assessed. Statistically significant differences were determined by repeated measures analysis of variance; the Tukey-Kramer test for multiple comparisons was used for post hoc comparisons. Three-day follow-up CT scans were obtained to check for procedure-related complications or delayed bleeding. RESULTS: The postbiopsy bleeding reduction groups showed significantly less blood loss than the control group for both the nonheparinized (p < 0.0001) and heparinized groups (p < 0.0001). In the heparinized group, both radiofrequency cauterization (p < 0.01) and gelatin sponge embolization (p < 0.05) significantly reduced bleeding compared with Histoacryl-Lipiodol mixture plugging. Gelatin sponge embolization was the longest procedure (p < 0.001). On follow-up CT, no delayed bleeding was observed. However, multiple Histoacryl-Lipiodol emboli were observed in the splenic and portal veins in all the dogs we treated. CONCLUSION: Radiofrequency cauterization was found to be the most useful postbiopsy bleeding reduction method in terms of the amount of bleeding and the procedure time.

Analysis of Variance↗

Value of contrast-enhanced sonography for the characterization of focal hepatic lesions in patients with diffuse liver disease: receiver operating characteristic analysis.

OBJECTIVE: Our aim was to assess the diagnostic performance of contrast-enhanced agent detection sonographic imaging to characterize focal hepatic lesions in patients with diffuse liver disease in comparison with baseline sonographic images and to determine whether agent detection imaging can reduce the necessity of further diagnostic workup for lesion characterization. MATERIALS AND METHODS: Contrast-enhanced sonography using 4 g of Levovist at a concentration of 300 mg/mL was performed on 75 focal hepatic lesions in 75 patients with diffuse liver disease. Interval reviews for both baseline without and with contrast-enhanced sonography were performed independently by two radiologists. They were requested to determine the malignity of focal hepatic lesions using a 5-point confidence level and to record the specific diagnoses and the necessity for further imaging for lesion characterization. Radiologists' performances for lesion differentiation using baseline and contrast-enhanced sonography were evaluated using receiver operating characteristic (ROC) analysis. Interobserver agreement was also analyzed. RESULTS: When contrast-enhanced sonography was used, ROC analysis revealed a significant improvement for both reviewers (area under the receiver operating characteristic curve [A(z)] = 0.753 and 0.830 and 0.971 and 0.974 at baseline sonography and contrast-enhanced sonography, respectively; p < 0.002) for differentiating malignant and benign focal liver lesions. Contrast-enhanced sonography also improved specificity from 12% to 91% for reviewer 1 and from 26% to 85% for reviewer 2 compared with baseline sonography. Furthermore, excellent interobserver agreement was achieved for contrast-enhanced sonography (weighted kappa = 0.919), whereas only good agreement was achieved for baseline sonography (weighted kappa = 0.656). A better result for specific diagnosis was obtained by contrast-enhanced sonography (79% and 75%) than by baseline sonography (37% and 48%, p < 0.05). Contrast-enhanced sonography (72% and 63%) outperformed baseline sonography (35% and 28%, p < 0.05) as a confirmatory imaging technique. CONCLUSION: Contrast-enhanced agent detection sonography can be used to characterize focal hepatic lesions in patients with diffuse liver disease reliably and with a higher diagnostic confidence than baseline sonography. Furthermore, contrast-enhanced sonography reduced the need for further diagnostic workups for focal hepatic lesion characterization.

Adult↗

Visualization of jejunal bleeding by capsule endoscopy in a case of eosinophilic enteritis.

Eosinophilic enteritis is a rare disease characterized by tissue eosinophilia, which can affect different layers of bowel wall. Normally, the disease presents as colicky abdominal pain, and rarely as an acute intestinal obstruction or perforation. In this paper, we report a case of eosinophilic enteritis, hitherto unreported, presenting as an ileal obstruction, and followed by jejunal bleeding, which was visualized by capsule endoscopy. A 62-year-old man received a 15 cm single segmental ileal resection at a point 50 cm from the IC valve due to symptoms of obstruction, which were diagnosed as eosinophilic enteritis. Seventeen days after operation, intermittent abdominal pain occurred again, and subsided upon 30 mg per day treatment with prednisolone. Fourteen days after this pain attack, the patient exhibited hematochezia, in spite of continuous prednisolone treatment. Capsule endoscopy showed fresh blood spurting from the mid-to-distal jejunum, in the absence of any mass or ulcer. This hematochezia rapidly disappeared following a high-dose steroid injection, suggesting it was a manifestation of jejunal eosinophilic enteritis.

Endoscopy, Gastrointestinal↗

VX2 carcinoma in rabbits after radiofrequency ablation: comparison of MR contrast agents for help in differentiating benign periablational enhancement from residual tumor.

PURPOSE: To prospectively compare the accuracy of a blood pool agent, SH L 643A, with that of gadopentetate dimeglumine in differentiating benign periablational enhancement from residual tumor in VX2 carcinomas in rabbits after radiofrequency (RF) ablation. MATERIALS AND METHODS: Experiment was approved by the animal care committee. Sequential MR images were obtained before and with SH L 643A (17 000 Da, 0.05 mmol/kg) and, after a 24-hour interval, gadopentetate dimeglumine (546 Da, 0.1 mmol/kg) in 12 rabbits with VX2 carcinoma in the back muscle prior to (n = 12) and early (n = 12), 1 week (n = 8), and 4 weeks (n = 4) after RF ablation. RF ablation was performed with output of 90 W but at less than 300 seconds to ensure incomplete tumor ablation. The pathologic specimens were sectioned in the same plane as MR imaging, and the enhancement ratios (ie, the ratios of postcontrast to precontrast signal intensity) and the microvessel densities of residual tumor and benign periablational enhancement were assessed. RESULTS: With SH L 643A, the peak enhancement ratios of residual tumor (1.64 +/- 0.31 [standard deviation]) were significantly higher than those of benign periablational enhancement (0.97 +/- 0.16) (P < .001). With gadopentetate dimeglumine, the peak enhancement ratios of residual tumor (1.82 +/- 0.33) were not different from those of benign periablational enhancement (1.71 +/- 0.36). In benign periablational enhancement, enhancement ratios with injection of SH L 643A were lower than those with injection of gadopentetate dimeglumine for all time points up to 30 minutes (P < .05). The microvessel density was 25.72 +/- 5.43 vessels per field of view for residual tumor and 10.37 +/- 2.88 vessels per field of view for benign periablational enhancement (P < .001). CONCLUSION: Blood pool contrast agent SH L 643A permits more accurate differentiation of benign periablational enhancement from residual tumor compared with the extracellular agent gadopentetate dimeglumine.

Animals↗

Four-dimensional volume contrast ultrasound imaging of the gallbladder compared with tissue harmonic imaging: preliminary experience.

Comparison of volume contrast US imaging with tissue harmonic imaging for the evaluation of gallbladder lesions and determination of the adequate slice thickness in volume contrast US imaging were performed. Forty-one patients who had gallbladder lesions (polyps in 26, stones in 12, and sludge in 3) were enrolled in our study. A Voluson 730 Expert US scanner was used throughout. Volume contrast US imaging with slice thicknesses of 3, 5, 10 and 15 mm and tissue harmonic imaging of the gallbladder were obtained. Two abdominal radiologists reviewed the masked images and graded by consensus these images using a five-point scale [from grade 1, (best), to grade 5, (worst)], based on the sharpness of the anterior gallbladder wall, internal artifact, lesion conspicuity and acoustic shadowing from stone. Volume contrast US imaging with thin slice thicknesses (3 or 5 mm) was judged superior to both tissue harmonic imaging and with thick slice thicknesses (10 or 15 mm), with respect to the sharpness of the anterior wall and lesion conspicuity ( P<0.001). In terms of internal artifact, volume contrast imaging with thin slice thicknesses was significantly superior to both tissue harmonic imaging and volume contrast imaging with a 15 mm thickness ( P<0.001) and was judged to be marginally better than with a 10 mm thickness ( p>0.01). With regard to acoustic shadowing, volume contrast imaging with thin slice thicknesses was also significantly better than with thick slice thicknesses ( P<0.01), and it was also marginally better than tissue harmonic imaging ( P>0.01). Volume contrast US imaging with thin slice thicknesses provides a better image quality with fewer artifacts than three other types of images for the evaluation of gallbladder diseases.

Adult↗