Keon Ha Kim

Distinguishing Tumefactive Demyelinating Lesions from Glioma or Central Nervous System Lymphoma: Added Value of Unenhanced CT Compared with Conventional Contrast-enhanced MR Imaging

PURPOSE To determine retrospectively whether unenhanced computed tomographic (CT) images of the brain have added value in distinguishing tumefactive demyelinating lesions (TDLs) from primary glioma or central nervous system (CNS) lymphoma, compared with conventional contrast material-enhanced magnetic resonance (MR) images only. MATERIALS AND METHODS This study was approved by the institutional review board, and informed consent was waived. Unenhanced CT and MR images in 15 patients with TDLs (seven women, eight men; mean age, 42 years; range, 27-57 years) and 48 patients with primary brain tumor (27 women, 21 men; mean age, 48 years; range, 19-70 years; 10 lymphomas, 38 gliomas) were retrospectively reviewed. The CT attenuation of regions that were enhanced or unenhanced at MR imaging was visually categorized into three grades, and CT attenuation values were determined quantitatively. The diagnostic accuracy of MR imaging for differentiating TDLs from tumors was compared with that of MR imaging plus CT. RESULTS The following MR imaging features were found more frequently in patients with TDL than in those with brain tumor: incomplete rim enhancement, mixed T2-weighted iso- and hyperintensity of enhanced regions, absence of a mass effect, and absence of cortical involvement (all P values < .05). CT hypoattenuation of MR enhanced regions was observed in 14 (93%) of 15 patients with TDL but in only two (4%) of 48 patients with tumor. The CT attenuation of MR enhanced regions was significantly lower for patients with TDL than for those with tumor (P < .001). The diagnostic accuracy of CT plus MR imaging was significantly higher than that of MR imaging alone (97% vs 73.0%, respectively; P < .001), and the diagnostic accuracy of CT was significantly higher than that of unenhanced T1-weighted MR imaging (95% vs 63%, P < .001). CONCLUSION Unenhanced CT plus MR imaging was more accurate for distinguishing TDLs from glioma or CNS lymphoma than contrast-enhanced MR imaging alone.

Intracranial and spinal ependymomas: review of MR images in 61 patients.

Objective To compare the age distribution and characteristic MR imaging findings of ependymoma for each typical location within the neuraxis. Materials and Methods During a recent eleven-year period, MR images of 61 patients with histologically proven ependymomas were obtained and retrospectively reviewed in terms of incidence, peak age, location, size, signal intensity, the presence or absence of cyst and hemorrhage, enhancement pattern, and other associated findings. Results Among the 61 patients, tumor location was spinal in 35 (57%), infrartentorial in 19 (31%), and supratentorial in seven (12%). In four of these seven, the tumor was located in brain parenchyma, and in most cases developed between the third and fifth decade. Approximately half of the infratentorial tumors occurred during the first decade. The signal intensity of ependymomas was non-specific, regardless of their location. A cystic component was seen in 71% (5/7) of supratentorial, 74% (14/19) of infratentorial, and 14% (5/35) of spinal cord tumors. Forty-nine percent (17/35) of those in the spinal cord were associated with rostral and/or caudal reactive cysts. Intratumoral hemorrhage occurred in 57% (4/7) of supratentorial, 32% (6/19) of infratentorial, and 9% (3/35) of spinal cord tumors. In 17% (6/35) of spinal ependymomas, a curvilinear low T2 signal, suggesting marginal hemorrhage, was seen at the upper and/or lower margins of the tumors. Peritumoral edema occurred in 57% (4/7) of supratentorial, 16% (3/19) of infratentorial and 23% (8/35) of spinal cord tumors. Seventy-two percent (5/7) of supratentorial and 95% (18/19) of infratentorial tumors showed heterogeneous enhancement, while in 50% (17/34) of spinal cord tumors, enhancement was homogeneous. Conclusion Even though the MR imaging findings of ependymomas vary and are nonspecific, awareness of these findings, and of tumor distribution according to age, is helpful and increases the likelihood of correct preoperative clinical diagnosis.

Gene delivery to the rat liver using cationic lipid emulsion/DNA complex: comparison between intra-arterial, intraportal and intravenous administration.

Objective To compare the efficiency of intra-arterial, intraportal, and intravenous administration of cationic lipid emulsion/DNA complex, as used for gene transfer to rat liver. Materials and Methods DNA-carrier complex for the in-vivo experiment was prepared by mixing DNA and a cationic lipid emulsion. According to the administration route used (intra-arterial, intraportal, or intravenous), the animals were assigned to one of three groups. The heart, lung, liver, spleen and kidneys were removed and assayed for total protein and luciferase concentration. Results The cationic lipid emulsion/DNA complex used successfully transfected the various organs via the different administration routes employed. Luciferase activity in each organ of untreated animals was negligible. Liver luciferase values were significantly higher in the groups in which intra-arterial or intraportal administration was used. Conclusion The intra-arterial or intraportal administration of cationic lipid emulsion/DNA complex is superior to intravenous administration and allows selective gene transfer to the liver.

Hypoechoic Normal Renal Sinus and Renal Pelvis Tumors Sonographic Differentiation

Objective. To evaluate the sonographic findings of an unusually hypoechoic renal sinus that mimics a tumor in the renal pelvis or renal sinus. Methods. Sonographic scans of 7 patients with an unusually hypoechoic portion in the renal sinus were reviewed retrospectively. Computed tomography, excretory urography, or both confirmed all sinuses as normal. Five consecutive cases of renal pelvis tumors, which were detected on sonography initially in same period, were also reviewed to determine the differences between the 2 conditions. All cases were transitional cell carcinomas of the renal calyces. The images were analyzed for location, shape, margin, presence of posterior sonic attenuation, and associated findings such as caliectasis. Results. Sonographic findings noted in patients with hypoechoic normal renal sinuses were irregular and poorly defined margins (n = 7), a central and symmetric location in the renal sinus (n = 6), the presence of posterior sonic attenuation with nonvisualization of the posterior border of the lesion (n = 7), an unaffected peripheral hyperechoic renal sinus (n = 7), and traversing hilar vessels in the lesion on color Doppler sonography (n = 7). In contrast, renal pelvis tumors had a relatively well‐defined margin (n = 4), an eccentric location in the renal sinus (n = 2), a partially or completely obliterated hyperechoic renal sinus (n = 2), a visible posterior margin (n = 5), no posterior shadowing (n = 5), vessel displacement by the mass on color Doppler sonography (n = 5), and associated caliectasis (n = 1). Conclusions. By being familiar with the sonographic characteristics of a hypoechoic renal sinus, it can be differentiated from renal pelvis tumors, and unnecessary diagnostic workups can be avoided.

Small atypical cervical nodes detected on sonography in patients with squamous cell carcinoma of the head and neck: probability of metastasis.

Objective. The purpose of this study was to assess the probability of metastasis of small atypical cervical lymph nodes detected on sonography in patients with squamous cell carcinoma (SCC) of the head and neck. Methods..We reviewed, retrospectively and blindly, sonographic findings of 148 patients (118 men and 30 women; mean age, 58.2 years) who underwent curative neck dissection. Each lymph node was classified by using a 4‐point scale: 1, definitely benign; 2, indeterminate (small [short‐axis diameter <10 mm for levels I and II and <7 mm for levels III–VI] atypical node); 3, definitely metastatic; and 4, large (>3‐cm) metastatic. Lymph nodes were considered atypical if they met at least 1 of the following criteria: a long‐ to short‐axis diameter ratio of less than 2.0, absence of a normal echogenic hilum, and heterogeneous echogenicity of the cortex. These results were verified, on a level‐by‐level basis, with histopathologic findings. Results. Small atypical nodes were found on sonography in 63 cervical levels of 48 patients, of which 18 (28.6%) were proved to have metastatic nodes. The probability of metastasis was significantly higher with than without a large (>3‐cm) ipsilateral metastatic node (0.50 versus 0.20; P = .038) and marginally higher with than without an ipsilateral metastatic node (0.41 versus 0.16; P = .061) but not significantly associated with the T stage of the primary tumor (P = .238) or the presence of an ipsilateral tumor (P = .904). Conclusions. Metastasis was encountered in about 30% of small atypical cervical nodes on sonography in patients with SCC of the head and neck. Our results indicate that small atypical nodes must be interpreted with consideration of metastatic nodes in the ipsilateral neck.