Measurement error of spiral CT Volumetry: Influence of Low Dose CT Technique

PURPOSE: To examine the possible measurement errors of lung nodule volumetry at the various scan parameters by using a small nodule phantom. MATERIALS AND METHODS: We obtained images of a nodule phantom using a spiral CT scanner. The nodule phantom was made of paraffin and urethane and its real volume was known. For the CT scanning experiments, we used three different values for both the pitch of the table feed, i.e. 1:1, 1:15 and 1:2, and the tube current, i.e. 40 mA, 80 mA and 120 mA. All of the images acquired through CT scanning were reconstructed three dimensionally and measured with volumetry software. We tested the correlation between the true volume and the measured volume for each set of parameters using linear regression analysis. RESULTS:For the pitches of table feed of 1:1, 1:1.5 and 1:2, the mean relative errors were 23.3%, 22.8% and 22.6%, respectively. There were perfect correlations among the three sets of measurements (Pearson's coefficient = 1.000, p<0.001). For the tube currents of 40 mA, 80 mA and 120 mA, the mean relative errors were 22.6%, 22.6% and 22.9%, respectively. There were perfect correlations among them (Pearson's coefficient = 1.000, p<0.001). CONCLUSION: In the measurement of the volume of the lung nodule using spiral CT, the measurement error was not increased in spite of the tube current being decreased or the pitch of table feed being increased.

Capillary Hemangioma of Adult Nasal Cavity: A Case Report

Capillary hemangioma of the adult nasal cavity is rare. We report a case which occurred in the right nasal cavity of a 25-years-old woman, together with the multiphase enhanced CT findings. The patients who had a history of recurrent nasal bleeding, had experienced nasal obstruction and swelling during the two-month period prior to presentation, and one month before presentation, spontaneous vaginal delivery occurred. Physical examination revealed the presence of a well-defined round mass, with redness in the right nasal vestibule. The mass showed rim enhancement at early arterial-phase CT scanning, increased enhancement at the late arterial phase, and moderately homogeneous enhancement at the delayed phase.

Recurrent Pyogenic Cholangitis: Clinico-Pathologic Correlation of Focal Attenuation Differences on Multi-Phasic Spiral CT

PURPOSE: To determine the clinical and the pathologic significance of the focal attenuation differences (FAD) and bile duct wall enhancement occurring in recurrent pyogenic cholangitis (RPC) and seen at multiphasic spiral CT. MATERIALS AND METHODS: Among the multiphasic (non-contrast, arterial and portal or delayed phase) spiral CT findings of 60 consecutive patients, two types of FAD were noted during the non-contrast phase. These were Type A (iso) and Type B (low attenuation), and their distribution pattern (lobar versus patchy, multifocal) and the and the presence or absence of bile duct wall enhancement were recorded. The radiologic findings were correlated with the clinical and pathologic findings. RESULTS: Two types of FAD were noted in 40 of the 60 patients. Active in flammation was present in 19 of the 27 with Type-A and in ten of the 15 in whom the presence of RPC was pathologically proven. Ten of the 13 with Type-B FAD were in a subclinical state, and nine of the ten in whom RPC was pathologically proven had chronic inflammation. Among 20 patients who did not have FAD, RPC was subclinical in 18 and dormant in nine of the eleven in whom its presence was pathologically proven (p<0.001). Clinico-pathologic correlation with bile duct wall enhancement and the distribution pattern of FAD showed no statistical significance. CONCLUSION: The inflammatory activity of RPC can be predicted by analysis of the FAD seen at multiphasic spiral CT.

Tumor Vascularity of Experimentally Induced VX2 Carcinoma in the Rabbit Thigh: Evaluation with Enhanced Power Doppler Sonography and DSA Correlated with Histopathologic Findings

PURPOSE: To describe findings of enhanced power Doppler sonography and DSA in experimentally induced VX2 carcinomas in rabbit thigh and to correlate the imaging findings with the histopathologic features. MATERIALS AND METHODS: A total of 30 VX2 carcinomas were implanted in rabbit thigh, and after conventional and enhanced power Doppler sonography and DSA, histopathologic examination was performed. Enhanced power Doppler sonography and DSA, were used to determine the distribution pattern of tumor vascularity; to assess its grade and the percentage of a tumor area occupied by vessels, conventional and enhanced power Doppler sonography, as well as DSA, were used. The grade of necrosis and the development of fibrovascular stroma and capsule were histopathologically determined. The findings of power Doppler sonography were compared with those of DSA and the imaging features were correlated with the histopathologic features. RESULTS: At enhanced power Doppler sonography, the signal was either avascular (n=9), peripheral (n=15) or diffuse (n=6), while at DSA, the corresponding totals were eight, fourteen and eight. There was statistically significant corelation between enhanced power Doppler sonography and DSA, both in their depiction of the distribution of patterns of tumor vascularity and as regards their findings of grade and percentage of vascular area. As determined by both conventional and enhanced power Doppler sonography, and by DSA, grade of necrosis and the development of fibrovascular stroma and a capsule correlated with grade and the percentage of vascular area. CONCLUSION: Experimentally induced VX2 carcinomas in rabbit thigh demonstrated various patterns of tumor vascularity, and the findings of enhanced power Doppler sonography correlated with those of DSA. Tumor vascularity, as demonstrated by two imaging modalities, correlated closely with grade of necrosis and the development of fibrovascular stroma and a capsule, as revealed by histopathologic examination.

Pulmonary Infection in AIDS

PURPOSE: To analyze the clinical and radiological manifestations of pulmonary infection in patients with AIDS. MATERIALS AND METHODS: We reviewed the medical records and analyzed retrospectively analysed the chestradiographs (n=24) and CT scans (n=11) of 26 patients with AIDS who had been followed up at our institute from1987 to June 1998. Pulmonary infections were confirmed by sputum smear and culture (n=18), pleuralexamination(n=3), bronchoalveolar lavage (n=3), autopsy (n=4), transbronchial lung biopsy (n=1) or clinicalhistory (n=9). The study group included 23 men and three women aged 25-54 (average 35.2) years. We correlated theradiologic findings with CD4 lymphocyte counts. RESULT: Pulmonary infections included tuberculosis (n=22),Pneumocystis carinii pneumonia (n=9), cytomegalovirus (n=3), and unidentified bacterial pneumonia (n=2).Radiologically pulmonary tuberculosis was classified as primary tuberculosis (n=11 ; mean CD4 counts: 41.3cells/mm3) and post-primary tuberculosis (n=11 ; mean CD4 counts: 251.3 cells/mm3). CT findings of tuberculosisincluded lymphadenitis (n=6), bronchogenic spread (n=5), large consolidation (n=4), esophago-mediastinal fistula(n=2), and cavity (n=1). Tuberculosis in AIDS responded rapidly to anti-TB medication with complete or markedresolution of lesions within three months. Radiologic findings of Pneumocystis carinii pneumonia included diffuseground glass opacities, cysts, and reticular opacities. CONCLUSION: Tuberculosis was the most common infection inpatients with AIDS in Korea, and this is attributed to the high prevalence of tuberculosis. Radiological findingsvaried with CD4+ cell count, showing those of primary tuberculosis as a patient's CD4+ cell count decreased.Pulmonary tuberculosis in AIDS responded rapidly to anti-Tb medication.

Liver Hmangioma: Comparison of Echogenecity and Contrast-enhancement on Dynamic MRI

PURPOSE: To evaluate the differences in sonographic appearance and hemodynamics between hypoechoic andhyperechoic hemangioma. MATERIAL AND METHOD: We retrospectively reviewed the sonographic appearance and MRIfindings of 23 hypoechoic hepatic hemangiomas in 16 consecutive patients. Nine were men and seven were women, witha mean age of 50 years(range, 40-72). We analyzed the sonographic appearance such as size, shape, border,echogenecity, posterior acoustic enhancement and the presence of fatty liver, and MRI findings such as signalintensity, enhancement pattern. For comparison, we also reviewed the sonographic appearance and MRI findings of 23hyperechoic hemangiomas in 16 randomly selected patients. RESULTS: There were no differences in size, shape,incidence of posterior acoustic enhancement, MR signal intensity or enhancement pattern between hypoechoic andhyperechoic hemangiomas(p>0.05, Chi-square). However, fatty infiltration of the liver and echogenic rim of themasses were more commonly seen in hypoechoic hemangiomas(9:1, 5:0, respectively, p<0.05). CONCLUSIONS: There wereno differences in MR enhomcement pattern or incidence of posterior acoustic enhancement between hypoechoichyperechoic hemangioma. The vascularity of a mass therefore seems to contribute little to its echogenecity.

Local Vascular Complications of the Puncture Site in Angiography

PURPOSE: To evaluate the types, follow-up studies, and management of local vascular complications of the puncture site in transfemoral angiography. MATERIALS AND METHODS: Fourteen patients who suffered local vascular complications during angiography of postangiographically were evaluated. We reviewed their clinical findings, radiological follow-up studies(Doppler-USG, angiography), treatment and final outcomes. RESULTS: The complications were three cases of perforation which needed emergency treatment, three cases of thrombosis which occurred several hours after angiography, two cases of arteriovenous fistula and two cases of arteriovenous fistula combined with pseudoaneurysm which appeared a few days after angiography, and four cases of pseudoaneurysm that showed variable detection time, from a few days to several months. The causes of complication were faulty puncture sites, carelessness and vascular fragility due to underlying vascular diseases such as diabetes mellitus and atherosclerosis. The complications were evaluated by angiography or doppler-USG and eight cases were treated successfully by interventional methods(manual compression, USG-guided compression, coil embolization,thrombolysis). Five cases needed surgical intervention. It was decided not to treat one case, but only to observe it. CONCLUSION: Local vascular injuries are serious complications occurring during angiography or postangiographically. They may, however, be properly controlled by various interventional techniques. It is important to be aware of their occurrence, findings and method of management.