An Effect of Time Gating Threshold (TGT) on the Delivered Dose at Internal Organ with Movement due to Respiration / 의학물리

In this study, we investigated the effect of time gating threshold on the delivered dose at a organ with internal motion by respiration. Generally, the internal organs have minimum motion at exhalation during normal breathing. Therefore to compare the dose distribution time gating threshold, in this paper, was determined as the moving region of target during 1 sec at the initial position of exhalation. The irradiated fields were then delivered under three conditions; 1) non-moving target 2) existence of the moving target in the region of threshold (1sec), 3) existence of the moving target region out of threshold (1.4 sec, 2 sec). And each of conditions was described by the moving phantom system. It was compared with the dose distributions of three conditions using film dosimetry. Although the treatment time increased when the dose distributions was obtained by the internal motion to consider the TGT, it could be obtained more exact dose distribution than in the treatment field that didn't consider the internal motion. And it could be reduced the unnecessary dose at the penumbra region. When we set up 1.4 sec of threshold, to reduce the treatment time, it could not be obtained less effective dose distribution than 1 sec of threshold. Namely, although the treatment time reduce, the much dose was distributed out of the treatment region. Actually when it is treated the moving organ, it would rather measure internal motion and external motion of the moving organ than mathematical method. If it could be analyzed the correlation of the internal and external motion, the treatment scores would be improved.

Influence of Mn-DPDP on MRI and Proton MR Spectroscopy of the Liver

PURPOSE: To determine the influence of manganese dipyridoxyl diphosphate (Mn-DPDP) on MRI and proton MRS. MATERIALS AND METHODS: In an in-vitro study designed to determine changes in the lipid peak at 1.3 ppm, 4.7T MR equipment was used to obtain proton MR spectrographic images of a lipid solution of varying concentration, with and without Mn-DPDP. Before; at 10, 20, and 30 minutes; and at 1, 2, 4, and 24 hours after the IV injection of Mn-DPDP (10umol, 1ml/kg), the concentration of Mn in liver tissue was measured by atomic absorption spectrometry. At the same intervals, T1-weighted MR images were obtained, the signal intensity ofthe liver was thus determined, and the relative enhancement ratio was calculated. MRS of rabbit liver was performed serially at the same intervals, and the peak areas of metabolites, as well as their peak areas relative to lipids, were calculated. The findings were correlated with tissue Mn concentration. RESULTS: At 1.3 ppm with Mn-DPDP, MRS showed that the peak area of the lipid had decreased. Tissue Mn concentration increased just after Mn-DPDP injection and peaked after 20 minutes, decreasing to a level within the normal range after 24 hours. Serial changes in the signal intensity of the liver, as seen at MRI, showed a similar pattern to that of Mn concentration. There was reverse correlation between serial change in the peak area of lipids at 1.3 ppm and Mn concentration after Mn-DPDP injection. CONCLUSION: At T1-weighted MR imaging, the injection of Mn-DPDP led to the enhancement of liver tissue, and at MRS, the lipid peak at 1.3 ppm decreased. There was close correlation between these effects and tissue Mn concentration.

Preliminary Results of Stereotactic Radiosurgery Using Stereotactic Body Frame / 대한방사선종양학회지

PURPOSE: To evaluate efficacy and complication of stereotactic radiosurgery using stereotactic body frame. METHODS AND MATERIALS: From December 1997 to June 1999, 11 patients with primary and metastatic tumors were treated with stereotactic radiosurgery using stereotactic body frame(Precision Therapy(TM)). Three patients were treated with primary hepatoma and seven with metastatic tumor from liver, lung, breast, trachea and one with arteriovenous malformation on neck. We used vacuum pillow for immobilization and made skin marker on sternum and tibia area with chest marker and leg marker. Diaphragm control was used for reducing movement by respiration. CT-simulation and treatment planning were performed. Set-up error was checked by CT-Simulator before each treatment. Dose were calculated on the 80~90% isodose of isocenter dose and given consecutive 3 fractions for total dose of 30 Gy (10 Gy/fraction). RESULTS: Median follow-up was 12 months. One patient (9%) showed complete response and four patients (36%) showed partial response and others showed stable disease. Planning target volumes (PTV) ranged from 3 to 111 cc (mean 18.4 cc). Set-up error was within 5 mm in all directions (X, Y, Z axis). There was no complication in all patients. CONCLUSION: In primary and metastatic tumors, stereotactic radiosurgery using stereotactic body frame is very safe, accurate and effective treatment modality.

Proton MR Spectroscopic Features of Chronic Hepatitis and Liver Cirrhosis

PURPOSE: The purpose of this study was to evaluate change in the proton MR spectroscopic (1H-MRS) features of the liver according to changes in the severity of the chronic hepatitis spectrum (normal-chronic hepatitis-liver cirrhosis), and to determine the possibility of replacing liver biopsy by1 H-MRS. MATERIALS AND METHODS: Sixty profiles of 1H-MRS features from 15 normal volunteers, 30 cases of chronic hepatitis, and 15 of liver cirrhosis were evaluated. All cases of chronic hepatitis and liver cirrhosis were confirmed by biopsy, and histopathologic disease severity was categorized according to Ludwig 's classification. Using the STEAM(STimulated Echo-Aquisition Mode) sequence, 1H-MRS was performed. The ratios of peak areas of [glutamate+glutamine]/lipid, phosphomonoesters/lipid, [glycogen+glucose]/lipid, and [3.9-4 . 1ppm unknown peak]/lipid and their mean and standard deviation were calculated in normal, chronic hepatitis stages I and II, and early and late liver cirrhosis groups and the results were compared between these groups. One-way variable analysis was applied to the statistics. RESULTS: Mean and standard deviation of phosphomonoesters/lipid in the normal, chronic hepatitis grades I and II, and early and late liver cirrhosis groups were 0.0146 +/-0.0090, 0.0222 +/-0.0170, 0.0341 +/-0.0276, 0 . 0 6 9 8 +/-0.0360, and 0.0881 +/-0.0276, respectively, and [glycogen+ glucose]/lipid were 0.0403 +/-0.0267, 0.0922 +/-0.0377, 0.1230 +/-0.0364, 0.1853 +/-0.0667, and 0.2325 +/-0.1071, respectively. These results implied that the ra-tio of the above metabolites to lipid content increased according to increasing disease severity (p<0.05). For [g-lutamate+glutamine]/lipid however, the ratios for each group were 0.0204 +/-0.0067, 0.0117 +/-0.0078, 0.0409 +/-0.0167, 0.0212 +/-0.0103, and 0.0693 +/-0.0371, respectively, and there was no correlation with disease severity. In the chonic hepatitis grades I and II, and early and late liver cirrhosis groups, the ratios for [3.9 -4.1 ppm un-known peak]/l ipid were 0.0302 +/-0.0087, 0.0513 +/-0.0167, 0.1112 +/-0.0351, and 0.1504 +/-0 . 0 3 5 5 ,and these also increased according to increasing disease severity (p<0.05). On MR spectra of normal livers, an unknown peak at 3.9 -4.1ppm was not detected. CONCLUSION: Changes in MR spectroscopic features in cases of chronic hepatitic and liver cirrhosis correlated with changes in disease severity, and the sensitivity of the unknown peak at 3.9 -4.1ppm changed according to disease severity. It is therefore possible to differentiate between normal liver, chronic hepatitis and liver cirrhosis by analysis of the 1H-MRS features of the liver. These results indicate that in cases of chronic hepatitis and liver cirrhosis, biopsy of the liver can be replaced by 1H-MRS.

Sequential Radiographic Changes of Nodules in Patients with Miliary Pulmonary Tuberculosis

PURPOSE: To evaluate sequential changes in miliary nodules, as seen on chest radiographs in patients withmiliary tuberculosis. MATERIALS AND METHODS: We retrospectively analyzed sequential changes in miliary nodules,as seen on the chest radiographs of 13 patients with miliary tuberculosis who recovered completely ofterantituberculous medication. Two were children and 11 were adults, and their ages ranged from 2 monts to 73years(mean, 38 years). In cases in which miliary tuberculosis had been diagnosed from initial chest radiographs,follow-up chest radiographs were obtained 5 to 15(mean, 10) months later. After complete resolution of miliarynodules, as seen on chest radiographs, high-resolution CT scanning was performed in three patients. RESULTS: Asseen on follow-up chest radiographs obtained at one week, the number and size of miliary nodules had decreased ineight of nine patients (89%), and on those obtained at one month, these decreases were seen in all 13 patients.The mean duration of complete resolution of miliary nodules was 6.3 months ; in children, this was 3.5(range, 2-5)months, and in adults, 6.8 (range, 3-10) months. In all three patients involed, high-resolution CT scans obtainedafter complete radiographic resolution of miliary nodules showed no recurrence. CONCLUSION: In patients withmiliary tuberculosis, the size and number of nodules had decreased within one month of adequate chemotherapy andon chest radiographs, complete resolution was seen at 6.3 months, on average.

CT Measurement of Normal Pericardial Thickness in Adults on Computed Tomography

PURPOSE: The purpose of this study was to establish, using computed tomography, the normal thickness of thepericardium in adults. MATERIALS AND METHODS: CT scans of 50 patients, including sections through the level of theheart, were reviewed. Patients were excluded if there were any suspicions of pericardial abnormality such asinfectious or neoplastic diseases. Twenty-four of the 50 were men and 26 were women; their mean age was 47.0(range,18-76) years. We measured pericardial thickness at the level of the right ventricle, interventricularseptum and left ventricle, and also compared pericardial thickness in terms of age and sex. RESULTS: In allpatients, the pericardium was observed in the right ventricular region; in 41 (82%) at the interventricularseptum; and in 41 (82%) along the left ventricle. The mean thickness of normal pericardium at the level of theright ventricle, interventricular septum, and left ventricle was 1.8 mm +/- 0.5 mm, 1.8 mm +/- 0.4 mm, and 1.7 mm +/-0.5 mm, respectively. No statistically significant correlation was apparent between pericardial thickness and agegroup (p > 0.63, ANOVA test). Mean pericardial thickness was 1.9 mm +/- 0.6 mm in males and 1.7 mm +/- 0.4 mm in females; thus, no statistically significant correlation was apparent between pericardial thickness and sex (p >0.29, Student's t-test). CONCLUSION: The pericardium was best visualized in sections through the right ventricle.The mean thickness of normal pericardium was 1.8 mm +/- 0.5 mm and pericardial thickness did not differ accordingto age or sex.

Distribution of Pleural Effusion Associated with Ascites on Abdominal CT

PURPOSE: To determine through an analysis of the location of pleural effusion associated with ascites, as seen on abdominal CT scan, differences in the distribution of pleural effusion according to the etiology and distribution of ascites. MATERIALS AND METHODS: We retrospectively evaluated 77 consecutive patients in whom abdominal CT scan revealed pleural effusion associated with ascites. Patients with history of surgery or trauma and those with clinically and radiologically diagnosed lung or pleural diseases were excluded. We compared the location of pleural effusion with the etiology and distribution of ascites. RESULTS: Forty-two patients were suffering from hepatobiliary diseases, mainly right dominant pleural effusion (26/42, 62%). Fourteen had intraperitoneal carcinomatosis with no significant difference between the frequency of right dominant (5/14, 36%)and of left dominant (6/14, 43%) pleural effusion. Eleven patients had pancreatic diseases, with mainly left dominant pleural effusion (6/11, 55%). Patients with right dominant ascites usually had right dominant pleural effusion (22/24, 92%) and those with left dominant ascites had left dominant pleural effusion (9/10, 90%). CONCLUSION: Ascites-associated pleural effusion correlated with the anatomical location of the etiology of ascites ; its laterality was, in addition, usually the same as that of ascites.

CT Evaluation of Target-like Bowel Wall Thickening

PURPOSE: The purpose of this study was to evaluate the CT features of target-like bowel wall thickenings and to correlate target layers with histopathologic layers. MATERIALS AND METHODS: We retrospectively analyzed 37 target-like bowel wall thickenings with inner high-, middle low- and outer high attenuated layers on CT scan. Bowel lesions included 15 cases of ischemic lesion, 12 of inflammation, four of carcinomatosis, four of trauma, and two of radiation enteritis. Target-like bowel wall thickenings were classified into three types : with inner most thickened high-attenuated layer(type I); with middle most thickened low-attenuted layer(type II), and with outer most thickened high-attenuated layer(type III). We analyzed the characteristic CT features of these bowel lesions and correlated target and histopathologic layers in resected bowel specimens. RESULTS: Target-like bowel wall thickening was type I in 18 cases(49%), type II in 13 cases(35%), and type III in 6 cases(16%). Type I ischemic bowel lesions and inflammations were most common, and were found in 60% and 67% of cases, retrospectively. All cases of trauma were type II and radiation colitis was type III. Histopathologic findings showed that each layer of target lesions did not exactly correlate with histopathologic layers. However, the inner high attenuated layer correlated with mucosa and some submucosa, the middle low-attenuated layer correlated with most submucosa and some muscularis, and the outer high-attenuated layer correlated with muscularis, serosa, and periserosal mesentery. CONCLUSION: CT features of target-like bowel wall thickenings showed type characteristics according to bowel lesions. Histopathologic comparison and analysis were considered helpful for the differential diagnosis of bowel lesions.

Differential Diagnosis of Medchanical Bowel Ostruction and Paralytic Ileus on CT Features

PURPOSE: To evaluate CT findings for the differential diagnosis of mechanical bowel obstruction and paralytic ileus. MATERIALS AND METHODS: Without information relating to clinical or operative findings, we retrospectively analyzed the CT scans of 24 patients with mechanical bowel obstruction and 19 patients with paralytic ileus. Final diagnosis was confirmed by operation (n=26), or by clinical symptoms, radiologic findings and follow-up study CT findings were obtained : 1) the diameter of the most dilated part of the small bowel, and the thickness and enhancing pattern of the dilated small bowel wall; 2) the diameter of the most dilated part of the descending colon and the ratio of the diameter of the small bowel to that of the descending colon; 3) the number of transitional zones, length and thickness. and 4) associated ascites and its location. RESULTS: The mean diameters of the most dilated part of the small bowel in mechanical bowel obstruction and paralytic ileus were 3.6cm and 2.9cm, respectively. The diameter of the small bowel in mechanical bowel obstruction was significantly greater than in paralytic ileus(p< .05). The mean thickness of dilated small bowel wall was 4.0mm in mechanical bowel obstruction and 2.4mm in paralytic ielus, and target-like enhancement was prominent in mechanical bowel obstruction (46%) (p< .05). he mean diameter of the most dilated part of the descending colon was not significantly different to that of the most dilated part of the small bowel, but the ratio of the diameter of the small bowel to that of the colon was 2.9 in mechanical bowel obstruction and 1.9 in paralytic ileus, respectively, which was statistically significant (p< .05). A transitional zone was seen in 23 cases (96%) of mechanical bowel obstruction and in nine (47%) of paralytic ileus. In mechanical bowel obstruction, mean transitional zone length was 2cm, shorter than that of paralytic ileus (3.4cm) (p< .05) The thickness of transitional zone and the presence of ascites and its locations were not significantly different between mechanical bowel obstrction and paralytic ileus. CONCLUSION: In the differential diagnosis of mechanical bowel obstruction and paralytic ileus, the following CT findings were considered useful : diameter of the most dilated part of the small bowel ; thickness and target-like enhancing pattern of dilated small bowel wall ; ratio of the diameter of the small bowel to that of the descending colon ; and the number of transitional zones, and their length.

Tracheal Luminal Diameter on Chest Radiographs: Demographic Data in 690 Normals

PURPOSE: To assess the normal range of transverse and AP diameter of the trachea on simple chest radiographs and to determine whether or not there is any correlation between tracheal diameter and age, sex, height, or bodyweight. MATERIALS AND METHODS: Six hundred and ninety patients with no lesion on chest radiographs and noclinical evidence of respiratory disease were involved in this study. To obtein transverse and lateral diameters,the internal diameter of the tracheal air column was measured at a level 2 cm above the top of the aortic arch onboth posteroanterior and lateral radiographs. RESULTS: The normal ranges of AP and transverse diameters of thetrachea were 16 to 25mm, and 14 to 22mm in men, respectively and 12 to 20mm and 12 to 18mm in women. Statistically significant differences were observed between AP and transverse diameter in both in men and women, the former being consistently larger than the latter in both sexes. In men, significant correlations were observed between transverse diameter and patients' height, and between AP diameter and age as well as height. In women, significant differences were observed between AP diameter and patients' height, and transverse diameter and height as well asbody weight of patients. CONCLUSIONS: Normal tracheal diameter was larger in men than in women. and AP diameter was larger than transverse diameter. Patients' height showed persistent correlation with luminal diameter.

Sequential Changes of Attenuation Values of Bile Duct and Gallbladder on CT after Oral Contrast Ingestion

PURPOSE: The purpose of this study is to evaluate that sequential CT scans after oral contrast ingestion can show morphological and functional status of the biliary tree, especially for the gallbladder and assess whether the CT scans demonstrate other radiological informations than conventional oral cholecystography. MATERIALS AND METHODS: Thirty volunteers in third decades and eight patients with hepatobiliary disease were included for the study. CT scans were obtained 3, 6, 9, 12 hours after oral contrast ingestion and thirty minutes after fat meal in thiry volunteers. Conventional oral cholecystography was also obtained in all volunteers at 12 hours after oral contrast ingestion and after fat meal. We evaluate opacification of gallbladder, biliary tree, and duodenum by contrast media on CT scans and attenuation values of gallbladder, common hepatic duct and common bile duct in each artatomic area on CT and its sequential change. CT scans were performed 6 hours after oral contrast ingestion in eight patients with hepatobiliary disease. And gallbladder function was evaluated by opacification of gallbladder by contrast media in all patients. RESULTS: In thirty volunteers, opacified gallbladder by contrast media was seen in all cases in all sequential periods of time on CT scans, but in 22 cases on conventional oral cholecystography. Contrast-filled intrahepatic ducts were demonstrated in 3 cases at 3 hours after oral contrast ingestion and 11 cases at 6 hours and were not seen thereafter. Contrast-filled common hepatic duct was noted in 28, 18 and 4 cases respectively at 3, 6 and 9 hours after oral contrast ingestion and the CT attenuation values of common hepatic ducts had become progressively decreased. Contrast-filled common bile duct was noted in 28, 18 and 4 cases respectively at 3, 6 and 9 hours and the CT attenuation values of common bile ducts were not changed untill 9 hours but slightly increased at 12 hours. Contrast media was noted in 7, 5, 6 and 5 cases at 3, 6, 9, and 12 hours in cystic duct and 8, 3, 2, 5 cases in duodenum. Contrast-filled cystic duct and duodenum were noted in 24 cases and 19 cases respectively on CT scans after fat meal. The CT attenuation values of gallbladder were increased in sequential periods of time and the difference of density of gallbladder between 3 hours and 6 hours was statistically significant(p=0.0001). The CT attenuation values of gallbladder at 6 hours were heighter than that in 3 hours, statistically. Opacified gallbladder were noted in 2 cases of fatty liver(n=2), 1 case of alcoholic liver disease(n=1), in 1 case of liver cirrhosis(n=1). Patients of gallbladder stone(n=2) or hepatocellular carcinoma (n=2) had non-opacified gallbladder on CT scans. CONCLUSION: The CT scans after oral contrast ingestion can show the morphological and functional aspects of gallbladder better than conventional oral cholecystography and can also show biliary trees and other surrounding structures, so it is helpful method for assessment of not only gallbladder diseases but also other hepatobiliary diseases.

Nasal Bone Fractures : Evaluation with Thin-section CP

PURPOSE: To determine the value of thin-section CT in the diagnosis of nasal bone fractures. MATERIALS AND METHODS: We evaluated the thin-section CT scans of 40 patients with nasal bone fracture. CT scans were obtained with both axial and coronal planes, 1.5mm collimation with 2mm interval, and 9.6cm field-of-view. The axial scan plane was kept parallel to the orbitomeatal line from the nasion to the lower limit of the nose and the coronal plane was kept perpendicular to the axial plane. The data were reconstructed with bone algorithm. Nasal bone fracture was classified into 1 of 3 types on thin section CT:(I) simple fracture;(ll) simple fracture with displacement;(III) comminuted fracture. Associated facial bone injuries were also evaluated Simple radiographs of nasal bone were reviewed for comparison. RESULTS: Six patients had simple fracture, 10 patients had simple fracture with displacement, and 24 patients had comminuted fracture. Twenty-six patients had associated facial bone injuries which included fracture of nasal septum (n=15), fracture of frontal process of maxilla (n=9), fracture of ethmoid (n=6), widening of nasofrontal suture (n=5), and fracture of nasolacrimal duct (n=2). In 15 of 40 patients, CT could identify nasal bone fractures not detected on simple radiographs. CONCLUSION: Thin-section CT is a valuable aid in the evaluation of nasal bone fracture for accurate identification, nature, and combined facial injury.

Transcatheter Instillation of Urokinase into Loculated Pleural Effusion: Analysis of Treatment Effect

PURPOSE: To evaluate the indication for intracavitary Urokinase(UK) in the treatment of Ioculated pleural effusion. MATERIALS AND METHODS: We analyzed CT and US in 31 patients who were treated with intracavitary UK in Ioculated pleural effusion. In each patient, a single chest catheter (10-12F) was insected under imaging guidance. When the amount of drainage was less than 100ml/day, UK was instilled through the catheter until less than 50ml/day was drained. On follow-up chest radiographs of more than 1 month, we classified the results of treatment into 3 groups:(1) completely effective (lung expansion, over 80%);(2) partially effective (20-80%); (3) ineffective (below 20%) group. Sonographic pattern of pleural fluid was classified into anechoic, septated, and honeycomb appearances and the thickness of parietal pleura was measured on CT. RESULTS: Sixteen patients were completely effective, nine were partially effective, and six were ineffective. patients with completely or partially effective outcome had anechoic and linear septated appearance on had less than 4mm of parietal pleural thickness on CT. Of six ineffective patients, US showed linear septated in one patient and honeycomb appearance in five patients and the thickness of parietal pleura on CT was 3 mm in one patient, 4ram in two patients, 5mm in one patient, and 6mm in two patients. CONCLUSION: UK instillation through percutaneous catheter was an effective method in the treatment of Ioculated pleural effusion. However, we found near complete reaccumulation of pleural fluid when honeycomb appearance of pleural fluid on US or more than 5mm parietal pleural thickness on CT was observed, which might suggest that we should consider the other kinds of treatment method in those patients.

Intraperitoneal Fluid Collection: CT Characteristics in Dertermining the Causes

PURPOSE: Abdominal CT scans in patients with intraperitoneal fluid were retrospectively studied to identify characteristic features useful for differential diagnosis of various causes. MATERIALS AND METHODS: One hundred and seventy patients with intraperitoneal fluid collection were classified as categories of hepatic disease, carcinomatosis, and infectious disease. We analyzed sites of fluid collection, the presence of peritoneal thickening, omental and mesenteric fat infiltration, and lymph node enlargment. RESULTS: Intraperitoneal fluid was present in subhepatic space, subphrenic space, paracolic gutter, mesentery, and fossa of the gallbladder in decreasing order of frequency. Fluid in the gallbladder fossa was the most frequent in hepatic diseases. The fluid collection in subhepatic and subphrenic space was less frequent in infectious diseases. Peritoneal thickening was noted in infectious diseases, and carcinomatosis. Omental fat infiltration and enlarged lymph nodes were the most frequent in carcinomatosis (58% and 44%, respectively), whereas, mesenteric fat infiltration and enlarged lymph nodes were the most common in infectious diseases (61%, and 26%, respectively). CONCLUSION: The location of peritoneal fluid collection showed some lesion specific characteristics, and CT features of fat infiltration and enlarged lymph nodes of peritoneum, omentum, and mesentery were helpful for differential diagnosis between carcinomatosis and infectious diseases.

CT Diagnosis of Intestinal Obstruction: Findings and Usefulness

PURPOSE: To present the findings of intestinal obstruction and evaluate the value of CT in the diagnosis of intestinal obstruction. MATERIALS AND METHODS: We prospectively analyzed CT scans of twenty-two patients who were suspected to have intestinal obstruction. All 22 patients were confirmed with surgery:10 patients with adhesion, four with primary intestinal tumor, one with metastatic intestinal tumor, two with inflammatory bowel disease, two with intussusception, two with extrinsic compression by ovarian tumor, and one with inguinal hernia. The CT scans were evaluated with special attention to their causes, locations, and CT findings of intestinal obstruction. CT diagnosis and findings were compared with surgical results. RESULTS: Their causes were diagnosed correctly on CT scans in seventeen of 22 cases(77.3%). Locations of the intestinal obstruction were diagnosed correctly in 16 cases(72.7% ). The CT findings of intestinal obstruction were categorized into dilated proximal bowel loops with normal distal loops, thickening of the affected bowel wall, presence of the transitional zone, and no detectable abnormalities. The associated extraluminal findings were fat infiltration around the dilated bowel loops, ascites, and mesenteric lymphnodes enlargement. There were two limitations of CT in our study:first, no detectable differences between jejunum and ileum on CT scans, and second, difficulty in differential diagnosis between thickened bowel wall mimicking normal non-dilated segment and mechanical obstruction from tumors or inflammatory bowel diseases. CONCLUSION: We conclude that CT is useful method in the evaluation of causes and locations of intestinal obstruction and the demonstration of the associated extraluminal abnormalities.

CT Findings of Palpable Neck Masses in Children

PURPOSE: We performed this study to assess the value of CT in the differential diagnosis of palpable neck masses in children. MATERIALS AND METHODS: We retrospectively reviewed the CT scans of the palpable neck masses in 30 children. The masses were proved histopathologically and classified into cystic, solid, and inflammatory mass and their CT findings were analyzed. RESULTS: Twelve cases were cystic masses, 4 were solid masses, and 14 were inflammatory lesions. Cystic masses included cystic lymphangiomas (n=6), branchial cleft cysts (n=3), thyroglossal duct cysts (n=2), and ranula (n=l). Cystic lymphangiomas showed insinuating appearances into adjacent structures and 4 cases occurred in the posterior cervical space. All branchial cleft cysts were round cystic masses with smooth wall and displaced the submandibular gland anteriorly and the sternocleidomastoid muscle posteriorly. Two thyroglossal duct cysts occurred centrally adjacent to the hyoid bone and 1 ranula in the submental area. Solid masses were juvenile hemangioma, pleomorphic adenoma in submandibular gland, neurilemmoma, and fibromatosis colli. Juvenile hemangioma showed well-enhancing mass with indistinct margin and the other solid masses had well-defined margin with their characteristic location. Inflammatory lesions were abscess (n=4), deep neck infections with lymphadenopathy (n=4), submandibular gland inflammation (n=3), and tuberculous lymphadenitis (n=3) and they showed strand-like enhancement in adjacent subcutaneous tissues. Tuberculous lymphadenitis had multiple lymph node enlargement with internal low attenuation areas and showed less surrounding strand-like enhancement than suppurative lymphadenopathies. CONCLUSION: Most neck masses in infants and children were of congenital or inflammatory origin. CT is useful for the evaluation of the child presenting with a neck mass, because it can differentiate various forms of neck masses and is able to reveal the relationship of the masses to the adjacent structures with their characteristic location.

Radioopaque Intrahepatic Duct Stones in Plain Radiograph: Case Report

We experienced 3 cases of intrahepatic duct stones detected on plain radiographs. The patients had history of multiple episodes of recurrent cholangitis. Radiographic characteristics of these stones included multiple, round or rectangular radioopaque densities surrounded by calcified rim; these densities showed a branching pattern along the intrahepatic ducts.

Comparative study of radiologic findings in reduced and nonreduced intussusception by barium enema

One hundred and eighty one cases, which comfirmed tobe intussusception, were reviewed retrospectively to identify the differences between radiologic findings of reduced and nonreduced intussusceptions by barium enema. The number of cases of reduced intussusception was 148 and nonreduced was 33, so the rate of reduction was 82%. On conventional radiographs, air-fluid levels were seen in 23 cases(15.5%) of the reduced intussusception and in 18 cases(54.6%) of the nonreduced intussusception, and soft tissue masses were seen in 20 cases(13.5%) of the reduced intussusception and in 2 cases(36.4%) of the nonreduced intussusception. The mean value of a ratio of maximal diameter of small bowel to interpedicular distance of L3vertebral body was 0.93 in the reduced intussusception and 1.25 in the nonreduced intussusception. On barium enema, the dissection sign was seen in 33.1% of the reduced intussusception and in 75.8% of the nonreduced intussusception. The morphologic abnormalities of ascending colon were seen in 11.5% of the reduced intussusception and in 38.7% of the nonreduced intussusception. So, the findings of the air-fluid level soft tissue mass, marked small bowel dilatation, dissection sign and morphologic abnormality of ascending colon were more frequently seen in the nonreduced intussusception than the reduced cases. There was no correlation between the location of intussusceptum and the reduction rate.

CT findings of cervical lymphadenopathy: morphological analysis

To evaluate the effectiveness of computed tomography for the differential diagnosis of cervical lymphadenopathy, we reviewed CT scans of 26 patients with cervical lymphadenopathy retrospectively. These included 10 patients with tuberculous lymphadenitis, 11 patients with metastasis and 5 patients with lymphoma, We evaluated the CT scans with a special attention to internal nodal density, feature of contrast enhancement and location of lymphadenopathy. Tuberculous lymphadenitis involved multiple nodes unilaterally and showed central low density with even or uneven rim enhancement, usually occurring in young patients (mean: 31.6 years). Two cases with tuberculous lymphadenitis showed calcifications within the lymph nodes. Lymphoma involved unilateral or bilateral nodes and appeared as conglomerated isodense mass with even rim enhancement. Metastasis involved multiple nodes unilaterally and showed focal, diffuse of mixed pattern of central low density with variable rim enhancement, usually occurring in old patients (mean: 59.4 years). Locations of most frequent lymph node involvements were internal jugular group (76%), spinal accessory group (54%) and retropharyngeal group(12%).

Evaluation of CT densities of intrahepatic duct stones

No abstract available.