Usefulness of 2D shear wave elastography for the evaluation of hepatic fibrosis and treatment response in patients with autoimmune hepatitis

Purpose@#The purpose of this study was to determine the usefulness of two-dimensional shear wave elastography (2D SWE) in the assessment of liver stiffness (LS) and dispersion slope (DS) to evaluate hepatic fibrosis and the treatment response in patients with autoimmune hepatitis (AIH). @*Methods@#Patients diagnosed with AIH who underwent 2D SWE between June 2014 and June 2021 were enrolled in this retrospective study. The patients were classified into four groups according to the histologic stage of fibrosis (F1-F4). The baseline characteristics, laboratory test results, histologic results, and 2D SWE results were analyzed. The diagnostic performance of LS measurements in hepatic fibrosis staging was investigated, and variables were compared before and after steroid treatment for AIH. @*Results@#In total, 69 patients were analyzed. The LS values differed according to the stage of liver fibrosis (P<0.001). The area under the curve for LS was 0.903, 0.815, and 0.854 for ≥F2, ≥F3, and F4, respectively. The diagnostic performance of LS measurements was significantly greater than that of serum biomarkers, except for fibrosis index-4 for F4 (P<0.05). Significant differences were observed in follow-up examinations in both the LS value and DS in patients who received steroid therapy (P=0.012 and P=0.011, respectively). @*Conclusion@#In conclusion, 2D SWE is a useful method for the assessment of hepatic fibrosis in patients with AIH. In follow-up examinations, LS and DS can be used as reliable parameters to evaluate the treatment response of AIH.

Reliability of Skeletal Muscle Area Measurement on CT with Different Parameters: A Phantom Study

Objective@#To evaluate the reliability of CT measurements of muscle quantity and quality using variable CT parameters. @*Materials and Methods@#A phantom, simulating the L2–4 vertebral levels, was used for this study. CT images were repeatedly acquired with modulation of tube voltage, tube current, slice thickness, and the image reconstruction algorithm. Reference standard muscle compartments were obtained from the reference maps of the phantom. Cross-sectional area based on the Hounsfield unit (HU) thresholds of muscle and its components, and the mean density of the reference standard muscle compartment, were used to measure the muscle quantity and quality using different CT protocols. Signal-to-noise ratios (SNRs) were calculated in the images acquired with different settings. @*Results@#The skeletal muscle area (threshold, -29 to 150 HU) was constant, regardless of the protocol, occupying at least 91.7% of the reference standard muscle compartment. Conversely, normal attenuation muscle area (30–150 HU) was not constant in the different protocols, varying between 59.7% and 81.7% of the reference standard muscle compartment. The mean density was lower than the target density stated by the manufacturer (45 HU) in all cases (range, 39.0–44.9 HU). The SNR decreased with low tube voltage, low tube current, and in sections with thin slices, whereas it increased when the iterative reconstruction algorithm was used. @*Conclusion@#Measurement of muscle quantity using HU threshold was reliable, regardless of the CT protocol used. Conversely, the measurement of muscle quality using the mean density and narrow HU thresholds were inconsistent and inaccurate across different CT protocols. Therefore, further studies are warranted in future to determine the optimal CT protocols for reliable measurements of muscle quality.

Reliability of Skeletal Muscle Area Measurement on CT with Different Parameters: A Phantom Study

Objective@#To evaluate the reliability of CT measurements of muscle quantity and quality using variable CT parameters. @*Materials and Methods@#A phantom, simulating the L2–4 vertebral levels, was used for this study. CT images were repeatedly acquired with modulation of tube voltage, tube current, slice thickness, and the image reconstruction algorithm. Reference standard muscle compartments were obtained from the reference maps of the phantom. Cross-sectional area based on the Hounsfield unit (HU) thresholds of muscle and its components, and the mean density of the reference standard muscle compartment, were used to measure the muscle quantity and quality using different CT protocols. Signal-to-noise ratios (SNRs) were calculated in the images acquired with different settings. @*Results@#The skeletal muscle area (threshold, -29 to 150 HU) was constant, regardless of the protocol, occupying at least 91.7% of the reference standard muscle compartment. Conversely, normal attenuation muscle area (30–150 HU) was not constant in the different protocols, varying between 59.7% and 81.7% of the reference standard muscle compartment. The mean density was lower than the target density stated by the manufacturer (45 HU) in all cases (range, 39.0–44.9 HU). The SNR decreased with low tube voltage, low tube current, and in sections with thin slices, whereas it increased when the iterative reconstruction algorithm was used. @*Conclusion@#Measurement of muscle quantity using HU threshold was reliable, regardless of the CT protocol used. Conversely, the measurement of muscle quality using the mean density and narrow HU thresholds were inconsistent and inaccurate across different CT protocols. Therefore, further studies are warranted in future to determine the optimal CT protocols for reliable measurements of muscle quality.

Usefulness of Mobile Computed Tomography in Patients with Coronavirus Disease 2019 Pneumonia: A Case Series

The coronavirus disease (COVID-19) outbreak has reached global pandemic status as announced by the World HealthOrganization, which currently recommends reverse transcription polymerase chain reaction (RT-PCR) as the standard diagnostictool. However, although the RT-PCR test results may be found negative, there are cases that are found positive for COVID-19pneumonia on computed tomography (CT) scan. CT is also useful in assessing the severity of COVID-19 pneumonia. Whenclinicians desire a CT scan of a patient with COVID-19 to monitor treatment response, a safe method for patient transport isnecessary. To address the engagement of medical resources necessary to transport a patient with COVID-19, our institutionhas implemented the use of mobile CT. Therefore, we report two cases of COVID-19 pneumonia evaluated by using mobilecone-beam CT. Although mobile cone-beam CT had some limitations regarding its image quality such as scatter noise, motionand streak artifacts, and limited field of view compared with conventional multi-detector CT, both cases had acceptable imagequality to establish the diagnosis of COVID-19 pneumonia. We report the usefulness of mobile cone-beam CT in patients withCOVID-19 pneumonia.

CT and MRI Findings of Small Bowel Involvement of Amyloidosis Mimicking Small Bowel Polyposis Syndrome: a Case Report

Amyloidosis is an all-inclusive disease of deposition of amyloid proteins in the extracellular spaces, which in localized or systemic form cause tissue damage and dysfunction. Herein, we report a case of small bowel involvement of systemic amyloidosis presenting with multiple polypoid wall thickening mimicking small bowel polyposis syndrome in an age 75 male. Interestingly, polypoid wall thickening and amyloidoma showed hypointensity on T2-weighted images. To our knowledge, there has been no literature describing MRI findings of poylpoid wall thickening and amyloidoma. Although the underlying mechanisms are unclear and need validation, hypointensity on T2-weighted images could be valuable in diagnosing small bowel involvement of amyloidosis in patients presenting with poylpoid wall thickening and amyloidoma.

Recent Issues on Body Composition Imaging for Sarcopenia Evaluation

Recently, sarcopenia has garnered renewed interest. Sarcopenia is a disease characterized by decreased skeletal muscle mass and strength/function, which can impair the quality of life and increase physical disability, adverse metabolic effects, and mortality. Imaging tools for evaluating and diagnosing sarcopenia have developed rapidly. Radiologists should be aware of sarcopenia and its clinical implications. We review current knowledge about sarcopenia, its pathophysiological impact, and advantages and disadvantages of methods for evaluation of sarcopenia focusing on body composition imaging modalities such as whole-body dual-energy X-ray absorptiometry, CT, and MRI. Controversial issues are discussed, including the lack of consensus and standardization of the disease definition, imaging modality, measurement methods, and diagnostic cutoff points.

Computed tomography morphologic features of pulmonary adenocarcinoma with brain/bone metastasis

BACKGROUND/AIMS: Brain and bone metastases are common in patients with lung cancer. The development of metastasis is associated with poor survival in lung cancer patients. Although tumor morphologic features on radiographs are routinely assessed for differentiation between benign and malignant lung nodules, they are not used to predict metastasis. We assessed morphologic features of pulmonary adenocarcinomas with brain/bone metastasis on computed tomography (CT) to identify related factors for metastasis. METHODS: We performed a retrospective analysis of initial chest CT findings (size, type of contour, percentage of necrosis, enhancement, presence or absence of calcification, and air cavity) from 2009 to 2010 of patients with brain or bone metastasis and compared the findings with those of patients without metastases. RESULTS: In total, 128 patients were included (78 men, 52 women; mean age 69 years; range, 36 to 87). Nineteen patients had brain metastases and 32 had bone metastases. Morphologic features associated with brain metastasis included size ≥ 50 mm (odds ratio [OR], 3.37; 95% confidence interval [CI], 1.24 to 9.17; p = 0.013), necrosis ≥ 30% (OR, 4.51; 95% CI, 1.62 to 12.55; p =0.002), and presence of calcification (OR, 3.97; 95% CI, 1.16 to 13.55; p = 0.035). Morphologic features associated with bone metastasis included necrosis ≥ 30% (OR, 4.639; 95% CI, 1.98 to 10.82; p < 0.001) and T 3 to 4 stage (OR, 2.53; 95% CI, 1.07 to 6.00; p = 0.031). CONCLUSIONS: We found that necrosis ≥ 30% was associated with pulmonary adenocarcinoma with brain and bone metastasis at initial chest CT morphologic feature. To validate these results, further research should be conducted.

Quantitative Measurement of Hepatic Fibrosis with Gadoxetic Acid-Enhanced Magnetic Resonance Imaging in Patients with Chronic Hepatitis B Infection: A Comparative Study on Aspartate Aminotransferase to Platelet Ratio Index and Fibrosis-4 Index

OBJECTIVE: To quantitatively measure hepatic fibrosis on gadoxetic acid-enhanced magnetic resonance (MR) in chronic hepatitis B (CHB) patients and identify the correlations with aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) values. MATERIALS AND METHODS: This study on gadoxetic acid-enhanced 3T MR imaging included 81 patients with CHB infection. To quantitatively measure hepatic fibrosis, MR images were analyzed with an aim to identify inhomogeneous signal intensities calculated from a coefficient of variation (CV) map in the liver parenchyma. We also carried out a comparative analysis between APRI and FIB-4 based on metaregression results. The diagnostic performance of the CV map was evaluated using a receiver-operating characteristic (ROC) curve. RESULTS: In the MR images, the mean CV values in control, groups I, II, and III based on APRI were 4.08 ± 0.92, 4.24 ± 0.80, 5.64 ± 1.11, and 5.73 ± 1.28, respectively (p < 0.001). In CHB patients grouped by FIB-4, the mean CV values of groups A, B, and C were 4.22 ± 0.95, 5.40 ± 1.19, and 5.71 ± 1.17, respectively (p < 0.001). The mean CV values correlated well with APRI (r = 0.392, p < 0.001) and FIB-4 (r = 0.294, p < 0.001). In significant fibrosis group, ROC curve analysis yielded an area under the curve of 0.875 using APRI and 0.831 using FIB-4 in HB, respectively. CONCLUSION: Gadoxetic acid-enhanced MR imaging for calculating a CV map showed moderate correlation with APRI and FIB-4 values and could be employed to quantitatively measure hepatic fibrosis in patients with CHB.

The Magnetic Resonance (MR) Imaging Features of Myxoid Liposarcoma Arising from the Mesentery: a Case Report

Primary mesenteric liposarcoma is rare. It is difficult to make an accurate preoperative diagnosis of the myxoid type of liposarcoma by using imaging such as ultrasound or computed tomography (CT) due to the very small amount of fat that is located in the tumor. We report a case of primary myxoid liposarcoma of the mesentery which was difficult to differentiate from other solid mesenteric tumors with a myxoid component such as low grade fibromyxoid sarcoma, myxoid leiomyosarcoma or myxoma. Use of chemical shift magnetic resonance (MR) imaging to detect small fat components and its cystic appearance with solid components on the MR images can be useful to differentiate myxoid liposarcoma from the other mesenteric tumors with a myxoid component.

Doppler ultrasonography measurement of hepatic hemodynamics during Valsalva maneuver: healthy volunteer study

PURPOSE: The aim of our study was to assess the hemodynamic change of liver during the Valsalva maneuver using Doppler ultrasonography. METHODS: Thirty healthy men volunteers were enrolled (mean age, 25.5+/-3.64 years). The diameter, minimal and maximal velocities, and volume flow of intrahepatic inferior vena cava (IVC), middle hepatic vein (MHV), and right main portal vein (RMPV) was measured during both rest and Valsalva maneuver. These changes were compared using paired t-test. RESULTS: The mean diameters (cm) of the intrahepatic IVC at rest and Valsalva maneuver were 1.94+/-0.40 versus 0.56+/-0.66 (P<0.001). The mean diameter (cm), minimal velocity (cm/sec), maximal velocity (cm/sec), and volume flow (mL/min) of MHV at rest and Valsalva maneuver were 0.60+/-0.15 versus 0.38+/-0.20 (P<0.001), -7.98+/-5.47 versus 25.74+/-13.13 (P<0.001), 21.34+/-6.89 versus 35.12+/-19.95 (P=0.002), and 106.94+/-97.65 versus 153.90+/-151.80 (P=0.014), respectively. Those of RMPV at rest and Valsalva maneuver were 0.78+/-0.21 versus 0.76+/-0.20 (P=0.485), 20.21+/-8.22 versus 18.73+/-7.43 (P=0.351), 26.79+/-8.85 versus 24.93+/-9.91 (P=0.275), and 391.52+/-265.63 versus 378.43+/-239.36 (P=0.315), respectively. CONCLUSION: The blood flow velocity and volume flow of MHV increased significantly during Valsalva maneuver. These findings suggest that hepatic vein might play an important role to maintain venous return to the heart during the maneuver.

Pleural fluid characteristics of pleuropulmonary paragonimiasis masquerading as pleural tuberculosis

BACKGROUND/AIMS: Pleuropulmonary paragonimiasis produces no specific symptoms or radiologic findings, allowing for the possibility of misdiagnosis. We evaluated the specific clinical and pleural fluid features of pleuropulmonary paragonimiasis masquerading as pleural tuberculosis. METHODS: We retrospectively analyzed the clinical and radiologic characteristics of 20 patients diagnosed with pleuropulmonary paragonimiasis between 2001 and 2011. RESULTS: In total, 17 patients presented with respiratory symptoms, including dyspnea (30%), hemoptysis (20%), cough (20%), and pleuritic chest pain (15%). Chest radiographs revealed intrapulmonary parenchymal lesions, including air-space consolidation (30%), nodular opacities (20%), cystic lesions (15%), ground-glass opacities (10%), and pneumothorax (5%). A pleural f luid examination revealed eosinophilia, low glucose levels, and high lactate dehydrogenase (LDH) levels in 87%, 76%, and 88% of the patients, respectively. These traits helped to distinguish pleuropulmonary paragonimiasis from other pleural diseases such as parapneumonic effusion, malignancy, and pleural tuberculosis. CONCLUSIONS: Pleuropulmonary paragonimiasis is often initially misdiagnosed as other pleural diseases. Therefore, it is important to establish the correct diagnosis. In patients with unexplained pleural effusion living in paragonimiasis-endemic areas, pleural fluid obtained by thoracentesis should be examined to distinguish pleuropulmonary paragonimiasis. When marked eosinophilia, high LDH levels, and low glucose levels are identified in pleural fluid, physicians could consider a diagnosis of pleuropulmonary paragonimiasis.

Combined Radiofrequency Ablation and Double Anti-Angiogenic Protein Therapy to Increase Coagulation Efficacy: An Experimental Study in a Murine Renal Carcinoma Model

OBJECTIVE: To evaluate whether suppression of tumor microvasculature by double anti-angiogenic protein (DAAP) treatment could increase the extent of radiofrequency ablation (RFA)-induced coagulation in a murine renal cell carcinoma model. MATERIALS AND METHODS: Renal cell carcinoma cell lines were implanted subcutaneously into 10 nude mice. Four mice received adenoviral DAAP treatment and 6 mice received sterile 0.9% saline solution as DAAP-untreated group. The effect of DAAP was evaluated according to the vascularity by contrast-enhanced ultrasound (CEUS) using microbubbles. Four DAAP-treated mice and 4 DAAP-untreated mice were then treated with RFA, resulting in 3 groups: no-therapy (n = 2), RFA only (n = 4), and RFA combined with DAAP treatment (n = 4). Immediately after RFA, the size of coagulation necrosis and mitochondrial enzyme activity were compared between the groups using analysis of variance (ANOVA) and post hoc test. RESULTS: The contrast enhancement ratio for tumor vascularization on CEUS was significantly lower in the DAAP treated group than in DAAP-untreated group (30.2 +/- 9.9% vs. 77.4 +/- 17.3%; p = 0.021). After RFA, the mean coagulation diameter was 0 mm for no-therapy group, 6.7 +/- 0.7 mm for the RFA only group and 8.5 +/- 0.4 mm for the RFA with DAAP group (ANOVA, p < 0.001). The area of viable mitochondria within the tumor was 27.9 +/- 3.9% in no-therapy group, 10.3 +/- 4.5% in the RFA only group, and 2.1 +/- 0.7% in the RFA with DAAP group (ANOVA, p < 0.001). CONCLUSION: Our results suggest the potential value of combining RFA with anti-angiogenic therapy.

Visualization of Tumor Angiogenesis Using MR Imaging Contrast Agent Gd-DTPA-anti-VEGF Receptor 2 Antibody Conjugate in a Mouse Tumor Model

OBJECTIVE: To visualize tumor angiogenesis using the MRI contrast agent, Gd-DTPA-anti-VEGF receptor 2 antibody conjugate, with a 4.7-Tesla MRI instrument in a mouse model. MATERIALS AND METHODS: We designed a tumor angiogenesis-targeting T1 contrast agent that was prepared by the bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) and an anti-vascular endothelial growth factor receptor-2 (VEGFR2) antibody. The specific binding of the agent complex to cells that express VEGFR2 was examined in cultured murine endothelial cells (MS-1 cells) with a 4.7-Tesla magnetic resonance imaging scanner. Angiogenesis-specific T1 enhancement was imaged with the Gd-DTPA-anti-VEGFR2 antibody conjugate using a CT-26 adenocarcinoma tumor model in eight mice. As a control, the use of the Gd-DTPA-anti-rat immunoglobulin G (Gd-DTPA-anti-rat IgG) was imaged with a tumor model in eight mice. Statistical significance was assessed using the Mann-Whitney test. Tumor tissue was examined by immunohistochemical analysis. RESULTS: The Gd-DTPA-anti-VEGFR2 antibody conjugate showed predominant binding to cultured endothelial cells that expressed a high level of VEGFR2. Signal enhancement was approximately three-fold for in vivo T1-weighted MR imaging with the use of the Gd-DTPA-anti-VEGFR2 antibody conjugate as compared with the Gd-DTPA-rat IgG in the mouse tumor model (p < 0.05). VEGFR2 expression in CT-26 tumor vessels was demonstrated using immunohistochemical staining. CONCLUSION: MR imaging using the Gd-DTPA-anti-VEGFR2 antibody conjugate as a contrast agent is useful in visualizing noninvasively tumor angiogenesis in a murine tumor model.

Molecular MR Imaging for Visualizing ICAM-1 Expression in the Inflamed Synovium of Collagen-Induced Arthritic Mice

OBJECTIVE: To determine the utility of intercellular adhesion molecule (ICAM)-1 antibody-conjugated gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA-anti-ICAM-1) as a targeted contrast agent for the molecular magnetic resonance imaging (MRI) in collagen-induced arthritis (CIA). MATERIALS AND METHODS: Three groups of mice were used: non-arthritic normal, CIA mice in both the early inflammatory and chronic destructive phases. The MR images of knee joints were obtained before and after injection of Gd-DTPA-anti-ICAM-1, Gd-DTPA, and Gd-DTPA-Immunoglobulin G (Ig G) and were analyzed quantitatively. The patterns of enhancement on the MR images were compared with the histological and immunohistochemical ICAM-1 staining. RESULTS: The images obtained after injection of Gd-DTPA-anti-ICAM-1 displayed gradually increasing signal enhancement from the moment following injection (mean +/- standard deviation [SD]: 424.3 +/- 35.2, n = 3) to 24 hours (532 +/- 11.3), rather than on pre-enhanced images (293 +/- 37.6) in the early inflammatory phase of CIA mice. However, signal enhancement by Gd-DTPA and Gd-DTPA-IgG disappeared after 80 minutes and 24 hours, respectively. In addition, no significant enhancement was seen in the chronic destructive phase of CIA mice, even though they also showed inflammatory changes on T2-weighted MR images. ICAM-1 expression was demonstrated in the endothelium and proliferating synovium of the early inflammatory phase of CIA mice, but not in the chronic destructive phase. CONCLUSION: Molecular MRI with Gd-DTPA-anti-ICAM-1 displays specific images targeted to ICAM-1 that is expressed in the inflamed synovium of CIA. This novel tool may be useful for the early diagnosis and differentiation of the various stages of rheumatoid arthritis.

Usefulness of a Small-Field Digital Mammographic Imaging System Using Parabolic Polycapillary Optics as a Diagnostic Imaging Tool: a Preliminary Study

OBJECTIVE: To evaluate the efficacy for spatial resolution and radiation dose of a small-field digital mammographic imaging system using parabolic polycapillary optics. MATERIALS AND METHODS: We developed a small-field digital mammographic imaging system composed of a CCD (charge coupled device) detector and an X-ray source coupled with parabolic polycapillary optics. The spatial resolution and radiation dose according to various filters were evaluated for a small-field digital mammographic imaging system. The images of a test standard phantom and breast cancer tissue sample were obtained. RESULTS: The small-field digital mammographic imaging system had spatial resolutions of 12 lp/mm with molybdenum and rhodium filters with a 25-micrometer thickness. With a thicker molybdenum filter (100 micrometer thick), the system had a higher spatial resolution of 11 lp/mm and contrast of 0.48. The radiation dose for a rhodium filter with a 25-micrometer thickness was 0.13 mGy within a 10-mm-diameter local field. A larger field image greater than 10 mm in diameter could be obtained by scanning an object. On the small-field mammographic imaging system, microcalcifications of breast cancer tissue were clearly observed. CONCLUSION: A small-field digital mammographic imaging system with parabolic polycapillary optics may be a useful diagnostic tool for providing high-resolution imaging with a low radiation dose for examination of local volumes of breast tissue.

Erratum

No abstract available.

Micro-CT System for Small Animal Imaging / 의학물리

We developed a high-resolution micro-CT system based on rotational gantry and flat-panel detector for live mouse imaging. This system is composed primarily of an x-ray source with micro-focal spot size, a CMOS (complementary metal oxide semiconductor) flat panel detector coupled with CsI (Tl) (thallium-doped cesium iodide) scintillator, a linearly moving couch, a rotational gantry coupled with positioning encoder, and a parallel processing system for image data. This system was designed to be of the gantry-rotation type which has several advantages in obtaining CT images of live mice, namely, the relative ease of minimizing the motion artifact of the mice and the capability of administering respiratory anesthesia during scanning. We evaluated the spatial resolution, image contrast, and uniformity of the CT system using CT phantoms. As the results, the spatial resolution of the system was approximately the 11.3 cycles/mm at 10% of the MTF curve, and the radiation dose to the mice was 81.5 mGy. The minimal resolving contrast was found to be less than 46 CT numbers on low-contrast phantom imaging test. We found that the image non-uniformity was approximately 70 CT numbers at a voxel size of ~55x55x100micrometer3. We present the image test results of the skull and lung, and body of the live mice.

Evaluation of Renal Microvasculature Using Micro-computed Tomography in Rat / 대한비뇨기과학회지

PURPOSE: Rodent models that mimic human renal diseases are being increasingly recognized as powerful tools in the development of new drugs and for evaluating the efficacy of novel therapeutics in a preclinical setting. However, there are few reports on microvasculature imaging of the urinary system in small animals. An experimental study was performed to evaluate the microvasculature in a rat kidney using micro- computed tomography(CT) with three-dimensional images. MATERIALS AND METHODS: Five Sprague-Dawley male rats(age: 10-12 weeks, weight: 200-250g) underwent a laparotomy under anesthesia with an intramuscular injection of 0.5cc xylazine hydrochloride and ketamine mixed solution(1:10). After ligation of the abdominal aorta and inferior vena cava immediately above the renal artery, a 24 gazed catheter was inserted into the abdominal aorta. A physiological solution and heparin(500U) were infused through the catheter to flush the blood from the renal vasculature. The kidney was enhanced using self-made contrast material. The excised kidney was frozen for the micro-CT scan. RESULTS: The mean longitudinal diameter and weight of the 10 resected kidneys was 1.95+/-0.15cm and 2.0+/-0.28g, respectively. The images were represented by three-dimensional arrays of cubic voxels with opacities in the blood vessels. In the section taken from the arrays, four regions of the kidney could be identified easily by their characteristic vascular features. CONCLUSIONS: Micro-CT is a promising method for evaluating the renal microvascular architecture in a rat kidney. It can for the foundation of an experimental study aimed at providing quantitative information on the urinary system in a rodent model.

Impact of the Use of Contrast-Enhanced Multidetector CT for Acute Appendicitis: A Prospective Comparison with the Alvarado Score

PURPOSE: To determine the diagnostic performance of contrast-enhanced multidetector CT (MDCT) and the Alvarado score for acute appendicitis. MATERIALS AND METHODS: MDCT and determination of the Alvarado score were prospectively performed in 282 patients with 146 pathologically proven cases of acute appendicitis and 136 pathologically proven or clinically diagnosed cases of non-acute appendicitis. To compare the diagnostic performance of MDCT and the Alvarado score, the patients were subdivided according to age and sex, and receiver operating characteristics (ROC) analysis and Spearman rank correlation were performed. RESULTS: ROC analysis revealed that the optimal cut off value of the CT appendicitis grades was 2 in all patients, resulting in a sensitivity of 96.6% and a specificity of 94.9%. The optimal cut off values of the Alvarado score was different according to age and sex, resulting in a sensitivity of 85.6% and a specificity of 48.5%. There was a significant correlation between the CT appendicitis grades and the surgical-pathological grades (r=0.496, p<.0001). However, no significant correlation was observed between the Alvarado score and the surgical-pathological grades. CONCLUSION: Contrast-enhanced MDCT has a higher diagnostic accuracy and significant correlation with pathological findings than those of the Alvarado score in patients with acute appendicitis.

Development of Microbubble Contrast Agents for High Frequency Ultrasound Microscopy

PURPOSE: To develop optimal microbubble contrast agents (MBCAs) for performing ultrasound microscopy when examining small animals. MATERIALS AND METHODS: We prepared three types of MBCAs. First, a mixture of three parts of 40% dextran and one part of 5% human serum albumin were sonicated with perfluorocarbon (PFC) (MB1-D40A5P). Second, three parts of 40% dextran and one part of 1% human serum albumin were sonicated with PFC (MB2-D40A1P). Third, all parts of 1% bovine serum albumin were sonicated with PFC (MB3-A1P). We measured the microbubbles' sizes and concentrations with using image analysis software. The acoustic properties of the microbubbles were assessed both in vitro and in vivo. RESULTS: The majority of the MB1-D40A5Ps had a diameter of 2-5 um, the mean diameter of the MB2-D40A1Ps was 2.5 um, and the mean diameter of the MB3-A1Ps was less than 2.0 um. Among the microbubbles, the MB1-D40A5Ps and MB2-D40A1Ps showed increased echogenicity in the abdominal vessels, but the duration of their contrast effect was less than 30 sec. On the contrary, the MB3-A1Ps exhibited strong enhancement in the vessels and their duration was greater than 120 sec. CONCLUSION: A microbubble contrast agent consisting of all parts of 1% serum albumin sonicated with PFC is an effective contrast agent for ultrasound microscopy.