Spiral CT in Kidney: Assumption of Renal Function by Objective Evaluation of Renal Cortical Enhancement

PURPOSE: To correlate the degree of renal cortical enhancement, objectively evaluated by means of spiral CT, with the serum level of creatinine, and to determine the extent to which this degree of enhancement may be used to detect renal parenchymal disease. MATERIALS AND METHODS: Eighty patients [M:F=50:30; age=25 -90 (mean, 53) years] with available serum level of creatinine who underwent spiral CT between September and October 1999 were included in this study. In fifty patients the findings suggested hepatic or biliary diseases such as hepatoma, biliary cancer, or stone, while in thirty, renal diseases such as cyst, hematoma, or stone appeared to be present. Spiral CT imaging of the cortical phase was obtained at 30 -40 seconds after the injection of 120 ml of non-ionic media at a rate of 3ml/sec. The degree of renal cortical enhancement was calculated by dividing the CT attenuation number of renal cortex at the level of the renal hilum by the CT attenuation number of aorta at the same level. The degree of renal cortical enhancement was compared with the serum level of creatinine, and the degree of renal cortical enhancement in renal parenchymal disease with that of the normal group. Among eighty patients there were five with renal parenchymal disease and 75 with normal renal function. RESULTS: The ratio of the CT attenuation number of renal cortex to that of aorta at the level of the renal hilum ranged between 0.49 and 0.99 (mean, 0.79; standard deviation, 0.15), while the serum level of creatinine ranged between 0.6 and 3.2 mg/dl. There was significant correlation (coefficient of -0.346) and a statistically significant probability of 0.002 between the ratio of the CT attenuation numbers and the serum level of creati-nine. There was a significant difference (statistically significant probability of less than 0.01) between those with renal parenchymal disease and the normal group. CONCLUSION: The use of spiral CT to measure the degree of renal cortical enhancement provides not only an effective index for estimating renal functional status but also a means of differentiating between patients with renal parenchymal disease and those who are normal.

Chordoma versus Chondrosarcoma of the Central Skull Base: MR and CT Findings

PURPOSE: It is known that due to both their imaging and pathologic features, the accurate differentiation ofchondrosarcoma from chordoma is difficult. Through an analysis of MR and CT findings, this study aims to determinethe differential points between these two tumors. MATERIALS AND METHODS: In 21 patients, CT and MR imagingstudies of chordoma(n=12) and chondrosarcoma(n=9) at the base of the skull were retrospectively reviewed.Diagnosis had been established by histologic examination of surgically removed specimens. Eleven of the chordomaswere subclassified as 'conventional' and one as 'chondroid'; eight chondrosarcoma were 'conventional' andone was 'myxoid'. Four chordoma patients underwent CT and MR ; in six, only MR was performed ; and in two, onlyCT. Eight chondrosarcoma patients underwent both CT and MR, while in one, only CT was performed. All scans wereretrospectively evaluated for the location(midline/off-midline), direction of extension, margin and shape, bonydestruction and calcification, MR signal intensity and enhancement patterns of the tumors. Degree of calcificationwas graded from I to III. RESULTS: The epicenter of the mass of ten chordomas (83%) was midline, in twochondrosarcomas(22%), this was off-midline. Foci of calcification were observed in three of eleven chordomas(27%),and heavy calcification (grade III) was observed in one. In contrast to these findings, foci of calcificationswere observed in eight of nine chondrosarcomas (89%) and grade III calcification was observed in five. In bothtumors, calcification was coarse. Between the two kinds of tumor, there were no significant difference in MRsignal intensity and enhancement patterns, margin and shape, or direction of extension. CONCLUSIONS: Although MRand CT findings were similar in both types of tumor, location and degree of calcification may be features whichusefully distinguish chordoma from chondrosarcoma.

Comparison of FSE and EPI with Brain MR Imaging

PURPOSE: To compare the usefulness of echo-planar imaging (EPI) and fast spin-echo (FSE) in routine brain MR imaging. MATERIALS AND METHODS: Twenty-five patients with various intracranial diseases were prospectively examined with T2-weighted MR imaging on a 1.5T unit using FSE, spin echo singl-shot EPI (SS-EPI) and multi-shot EPI (MS-EPI) techniques. For qualitative assessment, overall image quality, discrimination between cortical gray-white matter and between basal ganglia-white matter, lesion conspicuity, image distortion and artifacts (motion, ghost, flow, and susceptibility) were all evaluated using a subjective scoring system ranging from 1 to 4 (1 for the worst and 4 for the best). For quantitative assessment, contrast and contrast-to-noise ratio (CNR) were calculated for cortical gray-white matter, basal ganglia-white matter, and lesion-white matter. RESULTS: Overall image quality, discrimination between cortical gray-white matter, basal ganglia-white matter, and lesion-white matter, lesion conspicuity, image distortion and susceptibility artifacts showed the highest value in FSE and the lowest in SS-EPI. Motion artifacts were seen only in FSE, while flow and ghost artifacts were most commonly seen in SS-EPI. Contrast and CNR of anatomical and pathologic structures showed the highest value in FSE, especially for cortical gray-white matter and basal ganglia-white matter . CONCLUSION: With regard to overall image quality, image distortion, susceptibility artifacts, contrast and CNR, EPI is far inferior to FSE. In routine brain MR imaging., the usefulness of EPI techniques would therefore be very limited.

Superselective Intraarterial Chemotherapy into Bilateral Uterine Arteries in Uterine Cervical Carcinomas

PURPOSE: To assess the efficacy of superselective intra-arterial chemotherapy (SSIAC) via the bilateral uterine arteries in cases of cervical carcinoma. MATERIALS AND METHODS: Eighteen patients with stage IIa (n=10), IIb (n=7), or IIIa (n=1) cervical carcinoma underwent one (n=2) or two (n=16) courses of preoperative SSIAC with Vincristine, Cisplatin, and Mitomycin C. We estimated the extent of reduction of tumor volume and improvement of stage, comparing pre-SSIAC MRI to postoperative results. Tumor vascularity, as seen on uterine arteriography, and procedural complications, were also evaluated. RESULTS: A marked reduction in tumor volume was observed in all patients, an average reduction volume of 94.7%. Improvement of stage was noted in 16 patients, and in six of these, no residual viable tumor or microinvasive residual tumor was seen. On angiography, tumor hypervascularity was demonstrated in seven patients, but its degree was not substantially related to therapeutic response. In no case did significant systemic complications of result from chemotherapy; in one patient, however, we experienced a serious complication of necrotizing cystitis due to malpositioning of a catheter in the superior vesical artery. CONCLUSION: SSIAC via the bilateral uterine arteries is an effective complementary modality for the treatment of various stages of cervical carcinoma.

Thin Section Helical CT Findings of Klatskin Tumor and Benign Stricture: Cholangiographic Correlation

PURPOSE: The purpose of this study was 1) to describe the thin section helical CT findings of hilar cholangiocarcinoma and of benign stricture, and to discuss the differential points between the two disease entities and 2) using cholangiographic correlation, to evaluate the diagnostic accuracy of helical CT in determining the extent of hilar cholangiocarcinoma. MATERIALS AND METHODS: Twenty-seven patients with hilar cholangiocarcinoma and eight with benign biliary dilatation were studied. All except four with hilar cholangiocarcinoma, who underwent CT using a conventional scanner, were studied with two-phase helical CT. In all patients, cholangiographs were obtained by digital fluoroscopy after the injection of contrast materials into PTBD catheters. The level of obstruction was classified according to Bismuth, and 35 CT scans were studied blindly and retrospectively by two radiologists. The findings were analyzed for the presence of tumor, and then divided into two groups (cholangiocarcinomas and benign strictures), and the positive predictive value was calculated. The CT images of klatskin tumor were analyzed with special emphasis on the level and shape of the hilar obstruction. The level of biliary obstruction and extent of the tumor were carefully correlated with the results of cholangiography. RESULTS: Thin-section spiral CT correctly identified all tumor mass as a focal wall thickening obliterating the lumen. On arterial/portal phase CT scanning, 81% of infilterative tumors showed high attenuation. In all patients, differentiation between benign stricture and klatskin tumor was possible ; correct identification of the level of obstruction and extent of tumor, according to Bismuth's classification, was possible in 63% of cases. CONCLUSION: For correct diagnosis of hilar cholangiocarcinoma and differentiation of benign stricture, helical CT was highly accurate and effective. Because of limital Z-axis resolution, however, the exact intraductalextent of the tumor was less accorately diagnosed.

Liver Neoplasms: Atypical CT and MR Imaging Findings

The use of advanced imaging techniques in computed tomography(CT) and magnetic resonance imaging (MRI) has established the appearance of most common liver neoplasms. There are, however, considerable overlaps In the appearances of various pathologic entities on CT and MRI, and certain hepatic lesions can show unusual characteristics that may lead to misinterpretation, so it is important for the radiologist to be aware of these uncommon appearances. The purpose of this article is to illustrate the spectra of uncommon patterns and various diagnostic pitfalls encountered on CT and MRI of liver neoplasms.

Radiologic Findings of Neonatal Sepsis

PURPOSE: To review the simple radiographic and sonographic findings in infants with neonatal sepsis. MATERIALS AND METHODS: We retrospectively analyzed simple chest and abdominal radiographs, and brain sonograms in 36 newborn infants (preterm: term=23:13). With neonatal sepsis diagnosed by blood culture and clinical manifestations. RESULTS: Pulmonary parenchymal infiltrate excluding respiratory distress syndrome and pulmonary edema or atelectasis was found in 22 infants (61%). Paralytic ileus, hepatosplenomegaly, and necrotizing enterocolitis were present in 18 (50%), 9 (25%), and 1 (3%) infants, respectively, while skeletal changes suggesting osteomyelitis were found in three. Brain sonography was performed in 29 infants and in four, abnormalities were seen ; these comprised three germinal matrix hemorrhages and one intraparenchymal hemorrhage. In six patients (17%) radiologic examinations revealed no abnormality. CONCLUSION: In patients with neonatal sepsis, pulmonary infiltrates and paralytic ileus were common abnormalities. Although these were nonspecific, radiologic findings may be used to supplement clinical and laboratory findings in diagnosing neonatal sepsis and planning its treatment.

MR Imaging of Intramedullary Tumors of the Spinal Cord

PURPOSE: The purpose of this study was to evaluate the characteristic MR findings of intramedullary spinal cord tumors according to histologic diagnosis. MATERIALS AND METHODS: MR images of 34 patients with surgically-proven intramedullary spinal cord tumor were retrospectively reviewed. Histologic diagnosis revealed 15 ependymomas, ten astrocytomas, three hemangioblastomas, two oligidendrogliomas, one malignant schwannoma, one glioblastoma multiforme, one neuroblastoma and one ganglioglioma. MR images were analyzed for location, size, shape, signal intensity, and degree and pattern of contrast enhancement of the tumors. RESULTS: All tumors showed cord expansion and a varying extent of involvement ranging from 1.5 to 30cm. Variable degrees of contrast enhancement were seen in all cases. Cervical, cervico-thoracic, thoracic, and thoraco-lumbar spinal ependymomas accounted for three, two, six, and four cases, respectively, while four, two, and four cases of cervical, cervico-thoracic, and thoracic spinal astrocytomas respectively, were seen. Other tumors were located most commonly in the thoracic spinal cord. A sharply-defined tumor margin was seen in 13 of 15 ependymomas, in all three hemangioblastomas, one neuroblastoma and one ganglioglioma. Tumors usually showed slightly low- or iso-signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Peritumoral cysts were seen in nine ependymomas, one hemangioblastoma, and one astrocytoma, while peritumoral hemorrhage was seen only in three ependymomas. Relatively homogeneous enhancement was seen in nine of 13 ependymomas, all hemangioblastomas and one neuroblastoma. All ten astrocytomas showed a poorly defined tumor margin and heterogeneous enhancement. CONCLUSION: On the basis of characteristic MR findings, intramedullary cord tumors may be histopathologically diagnosed.

Imaging Findings of Osler-Weber-Rendu Disease Involving the Liver

A 62-year-old woman with hereditary hemorrhagic telangiectasia(HHT) or Osler-Weber-Rendu disease involving the liver is presented. Imaging findings including color Doppler sonograph and CT findings are described.