Cortical Magnetic Resonance Imaging Findings in Patients With Posttraumatic Olfactory Dysfunction: Comparison According to the Interval Between Trauma and Evaluation

OBJECTIVES: Patients with smell loss after craniocerebral trauma are known to have some brain abnormalities, but there was no study to analyze the findings according to the time interval between injury and evaluation. We aimed to identify whether the time interval may influence on the findings in the brain. METHODS: Medical records of 19 patients with posttraumatic olfactory dysfunction were reviewed. All of them underwent a magnetic resonance imaging and olfactory function tests. The patients were divided into early (n=10) and delayed (n=9) groups according to the time interval. RESULTS: Magnetic resonance imaging was taken at a mean time of 2.2 and 59.6 months after trauma in the early and delayed groups, respectively. Abnormal findings in the brain were found in 6 and 8 patients in the early and delayed groups, respectively. The olfactory bulb and orbitofrontal cortex were commonly affected olfactory pathways in both groups. In the early group, the abnormalities were brain tissue defect, hemorrhage, and focal edema whereas tissue defect was the only finding in the delayed group. In the early group, 5 of 6 patients with severe olfactory dysfunction showed brain abnormality while 1 of 4 patients with mild dysfunction had abnormality. In the delayed group, all the patients had severe dysfunction and 8 of 9 patients showed brain abnormality. CONCLUSION: Most patients with traumatic olfactory dysfunction had abnormality in the brain, and brain abnormality might be different according to the timing of evaluation. Furthermore, there might be an association between the severity of olfactory dysfunction and radiological abnormalities.

Differentitation between Primary Central Nervous System Lymphoma and Glioblastoma: Added Value of Quantitative Analysis of CT Attenuation and Apparent Diffusion Coefficient

PURPOSE: Purpose of this study was to determine if quantitative measures of CT attenuation and ADC values in combination with conventional imaging features can differentiate primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM). MATERIALS AND METHODS: Twenty-six patients with histologically-proven GBM (14 men and 12 women; median age, 50 years; age range, 22 - 73 years) and 14 patients with PCNSL (11 men and 3 women; median age, 61 years; age range, 41 - 74 years) were enrolled. Maximum CT attenuation, minimum ADC, and lesion to normal parenchyma minimum ADC ratios were measured in solid tumor regions. Conventional imaging features were evaluated for the following: ill-defined margin, homogeneous enhancement pattern, degree of necrosis, extent of tumor involvement and multiplicity. The Mann-Whitney test was used to compare maximum CT attenuation and minimum ADC values for PCNSL and GBM. Fisher's exact test was used to evaluate relationships between pathologic diagnoses and imaging features. RESULTS: The CT attenuations were similar for PCNSL and GBM (37.84 +/- 6.90 HU versus 37.00 +/- 5.54 HU, p = 0.68), but minimum ADC and minimum ADC ratio were significant lower in PCNSL than in GBM (595.01 +/- 228.28 10(-6) mm2/s versus 736.52 +/- 162.05 10(-6) mm2/s; p = 0.028, 0.87 +/- 0.26 versus 1.14 +/- 0.29; p = 0.007). PCNSL showed greater homogeneous enhancement and smaller necrotic areas than GBM (p = 0.003 and p < 0.001, respectively) and was more likely to have multiple tumors than GBM (p = 0.039). When necrotic PCNSL (n = 4) and necrotic GBM (n = 24) were compared, minimum ADC and minimum ADC ratios were also significantly lower in PCNSL, but CT attenuation were not. CONCLUSION: Although CT attenuation does not provide valuable information, minimum ADC and minimum ADC ratio and some imaging features can aid the differentiation of PCNSL and GBM.

MR Imaging of the Internal Auditory Canal and Inner Ear at 3T: Comparison between 3D Driven Equilibrium and 3D Balanced Fast Field Echo Sequences

OBJECTIVE: To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). MATERIALS AND METHODS: Thirty ears of 15 subjects (7 men and 8 women; age range, 22-71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. RESULTS: Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. CONCLUSION: Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear.

Analysis of the Hepatic Segments on the Isotropic Multi-planar Reformatted CT Images

PURPOSE: We wanted to evaluate the diverse distribution and relation of the hepatic segments, as divided by the portal venous territories, on the isotropic multi-planar reformatted (MPR) CT images and we wanted to find their correlation to the intrahepatic venous structures. MATERIALS AND METHODS: Fifty adult patients who underwent portal phase CT images and who had the normal liver contours at CT were included in our study. The portal phase images were obtained with a slice collimation and reconstruction interval of 1.25 mm, and they were reformatted in the coronal and sagittal planes with a slab thickness of 3 mm. For analysis of these MPR images, various terms were newly defined according to the portal venous territories (e.g., three vertical planes [right, middle and left] and one transverse plane and their plane angles, the transverse and longitudinal angles). Also, the dominant segments of the right lobe were newly divided into the S7- and S8-dominant types by comparing the transverse angles. The imaging analysis was then conducted for the following: (1) the diversity of the three vertical planes and the one transverse plane and their plane angles, (2) the proportion of the dominant segments of the right lobe and their relation with the plane angles, and (3) the correlation between the dominant segments and the intrahepatic venous structures. RESULTS: The number of the S7- and the S8-dominant types was 21 and 29, respectively. The vertical and transverse planes were undulating and diverse according to the dominant segments as follows: the plane angles of the right vertical and middle vertical planes were more vertical in the S7-dominant type than in the S8-dominant type (p < 0.001). The right transverse plane angle was more horizontal in the S8-dominant type (p < 0.05). The left transverse plane angle seemed to be rather vertical than horizontal. For the intrahepatic venous structures, despite of our limited data, the anomalous intrahepatic venous structures might have some correlation with the dominant segments. CONCLUSION: According to our results, we suggest that the isotropic MPR images could successfully depict the vertical and transverse planes of the real hepatic segments, as divided by the portal venous territories, which were diverse according to their dominant types.