Intervention Management of Arteriovenous Graft in Hemodialysis Patients / 한양의대학술지

Maintenance of well-functioning arteriovenous graft through interventional management is critical in the patients undergoing repeated, scheduled hemodialysis due to chronic renal failure (CRF). Understanding basics and procedures of intervention applied is critical to the people working in medical fields to adequately manage the patients. The author expects that through understanding interventional procedures, people working in this field adequately manage the patients undergoing hemodialysis due to CRF by well prepared medical aids.

Retroperitoneal Hemorrhage after Endoscopic Removal of a Fish Bone Stuck in the Duodenum of a Patient Receiving Hemodialysis / 대한소화기학회지

Fish bones are often ingested accidently. Most of them passes out through the gastrointestinal tract safely, but serious complications, such as perforation, abscess, obstruction, and bleeding in the gastrointestinal tract, can occur. An ingested fish bone can be easily removed by endoscopy, and surgery is rarely required. However, there may be complications related to the endoscopic procedure including mucosal laceration, bleeding, fever, and perforation. Here, we report a case of retroperitoneal hemorrhage developed after endoscopic removal of a fish bone stuck in the duodenal wall, and then resolved spontaneously by conservative care.

The Ultrasonographic Findings of Bifid Median Nerve

PURPOSE: We wanted to evaluate the ultrasonographic findings of bifid median nerve and its clinical significance. MATERIALS AND METHODS: We retrospectively reviewed five cases (three men and two women, mean age: 54 years) of incidentally found bifid median nerve from 264 cases of clinically suspected carpal-tunnel syndrome that were seen at our hospital during last 6 years. Doppler sonography was performed in all five cases and MR angiography was done in one case for detecting a persistent median artery. The difference (deltaCSA) between the sum of the cross-sectional areas of the bifid median nerve at the pisiform level (CSA2) and the cross-sectional area proximal to the bifurcation(CSA1) was calculated. RESULTS: The incidence of a bifid median nerve was 1.9%. All the patients presented with a tingling sensation on a hand and two patients had nocturnal pain. All the cases showed bifurcation of the nerve bundle proximal to the carpal tunnel. The margins appeared relatively smooth and each bundle showed a characteristic fascicular pattern. A persistent median artery was noted between the bundles in four cases. deltaCSA was more than 2 mm2 in four cases. CONCLUSIONS: Bifid median nerve with a persistent median artery is a relatively rare normal variance and these are very important findings before performing surgical intervention to avoid potential nerve injury and massive bleeding. We highly suggest that radiologists should understand the anatomical characteristics of this anomaly and make efforts to detect it.

A 43-year-old female patient with complaint of left flank pain / 대한내과학회지

No abstract available.

Clinical Utility of Access Blood Flow Measurement by Ultrasound Dilution in Hemodialysis Patients / 대한신장학회잡지

BACKGROUND: Prophylactic stenosis correction is important in the durability of the vascular access, and routine surveillance for the detection of stenosis has been widely recommended to allow preemptive intervention before thrombotic occlusion. The ultrasound dilution technique has been considering not only a popular and validated in vascular access surveillance, but also useful in the measurement of access recirculation and cardiac output. METHODS: Access flow, recirculation, and cardiac output of seventy-six hemodialysis patients with arteriovenous fistulae were measured by ultrasound dilution technique, followed by access flow measurement by color doppler ultrasound in sixty-four patients. Access stenosis was defined as 50% and more reduction in the diameter of vessels by color doppler ultrasound. Cardiac output of thirty-seven patients by echocardiography within a year was also analyzed. RESULTS: Access stenosis was diagnosed in six of sixty-four patients by color doppler ultrasound (9.4%). Access flow in the group with stenosis (621+/-322 mL/min) was lower than the group without stenosis (1, 005+/-633 mL/min), but no statistical significance was found. The access flow measured by ultrasound dilution technique was significantly correlated with color doppler ultrasound (r=0.436, p= 0.01). The cardiac output measured by ultrasound dilution technique was also significantly correlated with echocardiography (r=0.660, p=0.01). CONCLUSION: The data did not provide statistical significances for the detection of stenosis by ultrasound dilution technique. But this study suggests that ultrasound dilution technique is a useful method in the measurement of access flow, cardiac output and recirculation. We hope further prospective studies based on our data will be performed.

Inner Ear Anomalies Causing Congenital Sensorineural Hearing Loss: CT and MR Imaging Findings

Many congenital dysplasias of the osseous labyrinth have been identified, and the differential diagnosis of these dysplasias is essential for delivering proper patient management. We retrospectively reviewed the computed tomography (CT) and magnetic resonance (MR) imaging findings of 20 children who had congenital sensorineural hearing loss. The children included cases of enlarged vestibular aqueduct and endolymphatic sac (n=8), aplasia of the semicircular canal (n=4), lateral semicircular canal-vestibule dysplasia (n=3), common cavity malformations with a large vestibule (n=1), cochlear hypoplasia (n=1), Mondini's dysplasia with large vestibular aqueduct (n=1), Mondini's dysplasia with a large vestibule (n=1), and small internal auditory canal (n=1). Six cases were unilateral. Nine cases had combined deformities, and nine cases had cochlear implants. CT was performed with a 1.0-mm thickness in the direct coronal and axial sections with using bone algorithms. MR was performed with a temporal 3D T2 FSE 10-mm scan and with routine brain images. We describe here the imaging features for the anomalies of the inner ear in patients suffering from congenital sensorineural hearing loss.

Diagnostic Accuracy of Spiral CT in Detecting Hepatic Tumors: Evaluation Using Portogenously Implanted Hepatic VX-2 Carcinoma in Rabbit

PURPOSE: To assess, by means of CT-pathologic correlation, the ability of CT to detect hepatic VX-2 carcinomas in rabbits, and to determine the factors influencing the sensitivity of tumor detection. MATERIALS AND METHODS: By means of direct portal inoculation, VX-2 carcinomas were implanted in the liver of eight rabbits after laparotomy. Two weeks later, dual-phase spiral CT scanning was performed using scan parameters of 3-mm collimation and reconstruction intervals of 1 mm and 3 mm. Radiologic-pathologic correlation involved the comparison of CT images and pathologic slices. The sensitivity and positive predictive value with which each technique detected the presence of tumors were calculated. RESULTS: Using pathologic slices, 2-40 (mean, 9.1) mm in size, 65 tumor nodules were detected. Overall sensitivity and the positive predictive value were 63% and 73%, respectively. Sensitivities for tumors of 2-5 mm and 6-10 mm were 28% and 79%, respectively. For images reconstructed with a 1-mm interval, sensitivity was significantly higher than that where a 3-mm interval was used (79% vs. 46%), but sensitivities for arterial and portal-phase imaging were not significantly different. Among small tumors (< or = 10 mm), 63% (12/19) showed strong enhancement at arterial-phase imaging. Regarding tumor detection, inter-observer concordance between the three radiologists was excellent for portal-phase images (k=0.86 and 0.83 for 1 mm and 3 mm reconstruction intervals, respectively), and good for arterial-phase images (k=0.77 and 0.73 for 1 mm and 3 mm reconstruction intervals, respectively. CONCLUSION: Even where dual-phase scanning with 3-mm collimation is used, spiral CT is limited in its ability to detect tumors 5 mm or less in diameter, though overlapping reconstruction improves the sensitivity with which those of 6-10 mm are detected. In the evaluation of arterial-phase images obtained at contrast-enhanced dual-phase imaging, special attention should be given to small hyper-attenuating nodules.

Fetal Pericallosal Lipoma: US and MR Findings

We report a case of fetal pericallosal lipoma occurring at the anterior interhemispheric fissure and associated with agenesis of the corpus callosum. During targeted prenatal ultrasonography at 26 weeks' gestation, the lesion was seen as a highly echogenic mass. MR imaging performed at 35 weeks' gestation and during the postnatal period revealed a pericallosal fatty mass and agenesis of the corpus callosum.

Influence of Anatomical, Scanning, and Reconstructing Parameters on Image Quality of CT Angiography: Vascular Phantom Study

PURPOSE: To investigate the image quality of CT angiograms obtained with various anatomical, scanning, and reconstruction parameters using a phantom with small vessels, and to determine the technique appropriate to a specific vascular anatomy. MATERIALS AND METHODS: The vascular phantom consisted of three pairs of parallel tubes with a luminal size of 1, 2, and 3 mm. Using the phantom, CT scans were obtained at three inter-tubal distances (1, 2, and 3 mm), three angles of inclination relative to the z-axis (0 degree, 45 degree, and 90 degree), three collimation widths (1, 3, and 5 mm) and two pitch factors (1 and 2). Using axial images obtained at 1-, 2-, and 3-mm reconstruction intervals, two types of three-dimensional images were rendered, and the quality of 972 such images was subjectively graded in terms of edge definition and artifact by three radiologists. RESULTS: All vessels parallel to the z-axis showed good image quality irrespective of other factors. A pair of vessels separated by 1 mm appeared to be stuck to each other. As collimation width and reconstruction interval increased, image quality decreased significantly and artifact increased. The quality of images obtained at 3 mm collimation and with a 6 mm increment was significantly better where collimation and increment were both 5 mm (p=0.001). Vessels 1 mm in size suffered artifactual degradation, especially in the case of SSD images. Most obliquely oriented vessels showed stair-step artifact, which tended to be severe when the reconstruction interval was large. CONCLUSION: In small vessels perpendicular to or inclined relative to the z-axis, a smaller collimation width and reconstruction interval lessens image degradation. When wider scan coverage is intended, a larger pitch rather than a larger collimation width is recommended. To lessen the artifacts occurring where vessels are obliquely oriented, the reconstruction interval should be reduced.

Functional Imaging Study of the Human Cerebral Cortex Activation on 1.5-T MR

PURPOSE: Adequate image post-processing software, essential for functional magnetic resonance imaging (fMRI)of cerebral cortex activation, is not readily available; this study aimed to evaluate the usefulness of a homemade post-processing system for fMRI and to investigate the physiologic and anatomic sources of activation signals infMRI. MATERIALS AND METHODS: Twenty nine fMRIs of motor and visual cortices activated by hand movement and photic stimulation were performed using the GRE technique (TR/TE/flip angle : 80/60/40 degrees, 64x128 matrix) in 10 normal volunteers. By using post-processing software, final functional maps were subsequently obtained. In order to investigate physiologic and anatomic sources of activation signals, fMRIs of motor cortices were repeated with different echo times, flip angles and presaturation of adjacent sections. Activation signals were compared tocortical veins on MR venograms. RESULTS: All fMRIs were successfully performed and those activation signals were detected in regions well known as motor and visual cortices. Mean percentage changes of signal intensities (PCSIs)of activation signals at echo times of 15, 30, and 60 msec were 2.9%, 3.5%, and 12.5%, respectively (p < 0.01).Mean PCSIs of activation signals with 40 degreesnd 10 degreeslip angles were 11.1% and 6.6% (p < 0.01), and those of activation signals without and with presaturation of the adjacent sections were 8.9% and 5.2% (p < 0.01). The shape and location of activation signals corresponded well with those of cortical veins. CONCLUSION: The imagepost-processing system developed in this study is a useful method for fMRI of cerebral cortex activation. Both BOLD (blood oxygen level-dependent) and inflow effects contribute to the physiologic source of activation signals, and the cortical veins draining activated cortex are the main anatomic source of activation signals.

Histopathologic Study on Liver Tissue Damage after Injection of Various Contrast Materials into the Liver Parenchyma of Rat

PURPOSE: To evaluate the severity of tissue necrosis of liver according to various kinds of contrast materials used in percutaneous transhepatic procedure. MATERIALS AND METHODS: Four kinds of commercially available contrast material were used in the this study :meglumine ioxithalamate (ionic monomer, Telebrix 30, Guerbet, France), meglumine ioglicinate (ionic dimer, Rayvist 300, Schering, Germany), iopromide (nonionic monomer, Ultravist 300, Schering, Germany), and iotrolan (nonionic dimer, Isovist 300, Schering, Germany). The same amount(0.1 ml) of each contrast material was directly injected into the liver of Sprongue-Dawley rats. After two days and four weeks, the histopathologic findings of resected liver were assessed and analysed with special emphasis on the difference in the area of tissue necrosis between each group. RESULTS: In the liver resected 48 hours later, the area of necrosis was related to the osmolality and ionicity of contrast material used :the higher the osmolality, the wider the area of necrosis and ionic contrast material exhibited wider area of necrosis than nonionic contrast material. In the liver resected four weeks later, almost complete recovery was seen at the site of necrosis in all groups. CONCLUSION: Nonionic contrast materials caused less tissue necrosis than ionic contrast materials in percutaneous transhepatic procedure because of their lower osmolality.

CT Measurement of Wall Thickness of Early Gastric Cancer: Correlation with Upper GI Series

PURPOSE: The purpose of this study is to determine the detection rate of early gastric cancer and to measure the focal gastric wall thickening in computed tomography. MATERIALS AND METHODS: From November 1991 to November 1993, 19 patients (age;33--76 years, male ;female:4;5) with surgically proven early gastric cancer were examined by upper gastrointestinal series and abdominal computed tomography. Twenty lesions in these patients were included in this study. Computed tomography was performed with conventional technique using gastrografinR (17 cases) or water filling (2 cases) method in supine position. Additional scans were obtained either in right down decubitus (15 cases) or supine position (4 cases) with an ingestion of gas forming agent. We determined the detection rate of early gastric cancer at computed tomography and measured the maximum thickness of the lesion. RESULTS: The pathologic types of the early gastric cancer were type lib + IIc in 5 cases, type IIc in 6, type III in 3 and type I, I + IIc, Ila, lib, lib + III and IIc + III in one, respectively. Seventy-five percent (15 cases) of early gastric cancer was detected at upper gastrointestinal series and fifty percent (10 cases) at computed tomography. Computed tomography could detect 100% of elevated carcinomas (3/3) and 41% of depressed carcinomas (7/17). The maximum thickness of the lesion ranged from 7 mm to 11 mm (mean ;8mm). CONCLUSION: In a well-distended stomach, CT could detect focal gastric wall thickening (mostly, less than 1 cm) caused by early gastric cancer in half of the cases.

Balloon Dilatation for Postoperative Stricture of Gastrointestinal Tract

PURPOSE: To assess the effects and complications of balloon dilatation in the treatment of postoperative stricture at the gastrointestinal tract. MATERIALS AND METHODS: From February 1991 to July 1993, balloon dilatation was performed under fluoroscopic guidance on 5 patients (age:l month to 64 yrs, male:female=2:3) who previously had undergone abdominal surgery because of stomach cancer (n=2), congenital tracheoesophageal fistula (n=l), lye stricture (n=l), and colon cancer (n=l). Causes of the stricture were all benign (n=4) except for one (recurrence of malignant tumor). We dilatated the stricture site with balloon catheter (8--25 mm in diameter) 3 to 4 times per session which was repeated 1 to 5 times in each patient. Follow-up periods ranged 8 to 15 months after the treatment. RESULTS: Two out of four benign strictures were relieved at one session, and the remaining two needed repeated sessions of balloon dilatation. Symptoms did not improve in the patient with malignant stricture in~pite of balloon dilatation, and feeding jejunostomy was reginred. Partial tear of anastomosis site occurred in one patient, however, it did not require any treatment. CONCLUSION: Balloon dilatation is relatively safe and effective in the treatment of postoperative stricture at the gastrointestinal tract.