Voice Onset Time Variations of Korean Stop Consonants in Aphasic Speakers

OBJECTIVE: To compare the voice onset time (VOT) differences of Korean stops in the initial and intervocalic positions between the aphasic patients with peculiarities of aspiration and a control group. METHOD: We examined 15 aphasic patients (nine males, six females) who had suffered a stroke (average age 49.7 years) and 15 healthy controls (average age 47.4 years). An aphasia examination was made by an aphasia battery of three standard tests and VOT was analyzed instrumentally. Stop consonants in the initial and intervocalic position were measured to categorize them according to aphasia types, place of articulation, and manner of articulation. RESULTS: VOT of the aphasic patients with peculiarities of aspiration had a greater difference than that of the controls, indicating that the temporal non-coordination between the laryngeal adjustment and oral articulators of aphasic patients happens due to the VOT of stops in the initial and intervocalic positions (p<0.05). CONCLUSION: VOT of stop consonants in the initial position produced by aphasic patients tends to be proportional to their breathing. It can cause glottal width and make aphasic patients' VOT duration longer. Lastly, the method to measure the VOT of aphasic patients is more significant for the types of phonation than for the places of articulation, and makes it possible to induce abnormal VOT.

A Phantom Study for Revealing Factors Related to Image Distortion of Three-Dimensional Reconstruction Rotational Angiogram

PURPOSE: To determine, by means of a phantom study, the distortion-related factors and appropriate iodine concentration for three-dimensional reconstruction rotational angiography. MATERIALS AND METHODS: Four phantoms were created: crossed metal rods, one metal rod, one contrast rod, and a contrast rod under water. Iodine concentrations were 300, 250, 200, and 150 Img/ml, respectively. For each phantom, rotational angiography was performed in the rotational, right-angled (90 degree to rotational), intermedial (45 degree), close to rotational (20 degree), and close to right-angled (70 degree) planes. Two-dimensional projection images were transferred to a workstation at which 3D images were produced using the volume rendering technique. Image quality in each plane was evaluated in terms of opacity, homogeneity, and margin sharpness, which were graded as low, intermediate or high by two neuroradiologists who used images obtained in the right-angled plane as the standard reference. The same assessors evaluated in terms of the same parameters, cross-sectional images obtained at the central, intermedial, and peripheral portions of one metal rod positioned in the right-angled, close to right-angled, and intermedial planes, and in order to compare the values at different sites, one neuroradiologist measured the horizontal and vertical diameters of each cut image. RESULTS: Three-dimensional images of all four phantoms were high quality in the close to right-angled and intermedial plane, but in the rotational and close to rotational plane were degraded. In particular, metal rod images obtained in the rotational plane were poor for all three items. In these two planes, image quality was better for the contrast rod than the metal rod, and at 200 and 250 Img/ml concentrations than at 300 and 150 Img/ml concentrations. There was no significant difference in image quality, nor in measured values of the diameter between cut images. CONCLUSION: A three-dimensional image was more distorted when a linear object was placed at a lesser angle to the rotational plane and when inherent X-ray attenuation was greater, a finding which must be closely related to the beam-hardening artifact. Distortion was least at 200-250 Img/ml of iodine concentration, the concentration thought to be most appropriate for in-vitro 3D angiography.

Bilateral Agenesis of the Internal Carotid Artery: Case Report

Unilateral or, particularly, bilateral congenital agenesis of the internal carotid artery is a rare anomaly. We report an occurrence of the condition, arising bilaterally, and report the findings of magnetic resonance imaging and magnetic resonance angiography.

SENSE (Sensitivity Encoding) for Diffusion Tensor Imaging of the Brain

PURPOSE: The sensitivity encoding (SENSE) technique is increasingly being used with clinical MRI scanners. The object of this study is to compare the normative human data and image quality of the diffusion tensor imaging (DTI) with sensitivity encoding (SENSE) and standard single-shot EPI techniques. MATERIALS AND METHODS: 16 normal volunteers underwent single-shot echo-planar DTI with both standard and SENSE sequences using a 1.5 T Philips Intera MR scanner (TR/TE=6755/74 or 5871/66 ms, echo train length 127 or 67, NEX=3, matrix=128x128, FOV=220x220 mm, slice thickness=4 mm, b value=600 s/mm2, six orthogonal diffusion gradients). The diffusion tensor-encoded MR images were transferred to a PC workstation and analyzed using in-house software. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were calculated. The presence of artifacts (ghost susceptibility, eddy current) was graded with a two- or three-point scale. The ADC and FA values were measured in the major white matter tract and gray matter nuclei. The signal-to-noise ratio was also measured. Fisher's exact test and the Mann-Whitney test were used for the statistical analysis. RESULTS: With SENSE, the acquisition time was reduced from 2 min 57 sec to 1 min 22 sec for DTI. Susceptibility artifacts (around the brain stem and temporal base) and eddy current artifacts were significantly reduced on the SENSE DTI as compared with those on the standard DTI (p<0.05). No ghost artifacts were observed on the SENSE DTI, whereas such artifacts were observed in 14 cases (87.5%) on the standard DTI. The ADC value was not significantly different between the SENSE DTI and the standard DTI, whereas the FA values in the cerebral cortex and white matter were significantly higher on the SENSE DTI than on the standard DTI (p<0.05). The signal-to-noise ratio was 8.44 on the standard DTI and 11.40 on the standard DTI. CONCLUSION: The use of SENSE DTI significantly reduces the geometric distortion caused by artifacts, shortens the acquisition time, and allows a relatively high SNR to be maintained, but tends to erroneously increase the FA value of the tissue. Therefore, DTI with SENSE may provide better white matter fiber tracking and diffusivity indices when the imaging parameters for SENSE are optimized.

Measurement of Normal Intracranial Artery Diameter Using Three-dimensional Reconstruction Rotational Angiogram

PURPOSE: To evaluate the distribution of normal intracranial artery diameter according to sex and age, using three-dimensional reconstruction rotational angiography. MATERIALS AND METHODS: One hundred and twenty-five adults with normal intracranial arteries who underwent 3D rotational angiography (n=177) were included in this study. The arterial diameter was measured at four sites of the internal carotid artery (cavernous, paraophthalmic, supraclinoid, and distal), that of the middle cerebral artery at two (proximal and distal), and that of the anterior cerebral artery at one (middle). For each sex and age group ( or = 60 years), the mean diameter of the artery at these seven sites was calculated, and differences analysed. In addition, the middle cerebral artery diameter was compared between a younger group ( or = 50 years). RESULTS: The mean diameter at each site for each sex was as follows: male (mean+/-SD): 4.61+/-0.69, 3.96+/- 0.60, 3.48+/-0.45, 3.61+/-0.50, 2.44+/-0.32, 2.44+/-0.37, 1.81+/-0.32; female: 4.29+/-0.57, 3.83+/-0.56, 3.37+/-0.56, 3.52+/-0.48, 2.32+/-0.37, 2.30+/-0.36, 1.76+/-0.34. For those in their 40s, the diameter at five sites (all four sites of the internal cerebral artery and a distal middle cerebral artery) was significantly greater in males than in females. For other age groups, however, the difference between the sexes was absent, or was significant at only one (cavernous internal cerebral artery for those in their 30s) or two (proximal and distal middle cerebral artery for those in their 50s) of the seven sites. In the older age group, the diameter of the proximal middle cerbral artery was 2.59+/-0.35 mm in males and 2.38+/-0.37 mm in females. For the distal middle cerebral artery, the corresponding figures were 2.63+/-0.43 and 2.39+/-0.35 mm, respectively. For both sexes, the differences between the two age groups were significant. CONCLUSION: For those in their 40s, the normal diameter of the intracranial artery at most arterial sites was significantly greater in males than in females. The normal diameter of the middle cerebral artery was significantly greater or tended to be greater among the older group than the younger group (for males and females, respectively, 2.59+/-0.35 mm and 2.38+/-0.37 mm at the proxinal site, and 2.63+/-0.43 mm and 2.39+/-0.35 mm at the distal site).

Pulmonary Complications in Renal Transplantation

PURPOSE: To evaluate the radiographic and CT findings of pulmonary complications other than pulmonary edema arising from renal transplantation. MATERIALS AND METHODS: Among 393 patients who had undergone renal transplantation at our hospital during a previous ten-year period, 23 with pulmonary complications other than pulmonary edema were included in this study. The complications involved were infection caused by CMV (n=6), bacteria (n=4), fungus (n=4), tuberculosis (n=2), varicella (n=1) or chlamydia (n=1), and malignancy involving lung cancer (n=4) or Kaposi's sarcoma (n=1). Two chest radiologists reviewed all images. RESULTS: The complications manifesting mainly as pulmonary nodules were lung cancer(4/4), tuberculosis (1/2), and Kaposi's sarcoma(1/1). Pulmonary consolidation was a main feature in bacterial infection(4/4), fungal infection(3/4), tuberculosis(1/2), chlamydial infection(1/1), and varicellar pneumonia(1/1). Ground-glass attenuation was a main CT feature in CMV pneumonia(4/6), and increased interstitial marking was a predominant radiographic feature in CMV pneumonia(2/6). CONCLUSION: The main radiologic features described above can be helpful for differential diagnosis of the pulmonary complications of renal transplantation.

Human Tail: A Case Report

Human tail is a rare congenital anomaly in which a lesion protrudes from the lumbosacrococcygeal region. We encountered a case of human tail involving an intradural lipoma and tethered cord, occurring in a 1-day -old female who presented with an 8 cm-sized tail shown by MRI to arise from the S3-4 level. The cauda equina and film terminale were entrapped by the lipoma, but there were no bony abnormalities.

Imaging Findings of the Brain Abnormalities in Acute Lymphoblastic Leukemia of Children during and after Treatment

PURPOSE: We evaluated the imaging abnormalities of the brain observed during and after treatment of acute childhood lymphoblastic leukemia. MATERIALS AND METHODS: The study group consisted of 30patients (male: female= 19:11; mean age, 64months) with acute childhood lymphoblastic leukemia during the previous ten-year period who had undergone pro-phylaxis of the central nervous system. Irrespective of the CNS symptoms, baseline study of the brain involving CT and follow-up CT or MRI was undertaken more than once. We retrospectively evaluated the imaging findings, methods of treatment, associated CNS symptoms, and the interval between diagnosis and the time at which brain abnormalities were revealed by imaging studies. RESULTS: In 15 (50% ; male : female=9:6 ; mean age, 77months) of 30 patients, brain abnormalities that included brain atrophy (n=9), cerebral infarctions (n=4), intracranial hemorrhage (n=1), mineralizing microangiopathy (n=2), and periventricular leukomalacia (n=3) were seen on follow-up CT or MR images. In four of nine patients with brain atrophy, imaging abnormalities such as periventricular leukomalacia(n=2), infarction (n=1) and microangiopathy (n=1) were demonstrated. Fourteen of the 15 patients underwent similar treatment; the one excluded had leukemic cells in the CSF. Six patients had CNS symptoms. In the 15 patients with abnormal brain imaging findings, the interval between diagnosis and the demonstration of brain abnormalities was between one month and four years. After the cessation of treatment, imaging abnormalities remained in all patients except one with brain atrophy. CONCLUSION: Various imaging abnormalities of the brain may be seen during and after the treatment of acute childhood lymphoblastic leukemia and persist for a long time. In children with this condition, the assessment of brain abnormalities requires follow-up study of the brain.

Positional Shifting of HRCT Findings in Patients with Pulmonary Edema

PURPOSE: To assess the value of positional shifting to a gravity-dependent area, as revealed by HRCT, in differ-entiating pulmonary edema (PE) from other conditions. MATERIALS AND METHODS: Sixteen consecutive patients in whom plain radiographs suggested the presence of pulmonary edema but the clinical findings were indefinite underwent HRCT of the lung. For initial scanning they were in the supine position, and then in the prone position. Findings of ground-glass opacity, interlobular septal thickening and peribronchovascular interstitial thickening were analyzed in terms of the presence and degree of shifting to a gravity-dependent area, a grade of high, intermediate or low being assigned. RESULTS: PE was diagnosed in 8 of 16 cases, the remainder being designated as non-pulmonary edema (NPE). Ground-glass opacity was observed in all 16, while the degree of positional shifting was found to be high in ten (PE:NPE=6:4), intermediate in four (PE:NPE=2:2), and low in two (PE:NPE=0:2). There was no significant difference between the two groups (p > 0.05). Interlobular septal thickening was observed in all but two NPE cases; the degree of shifting was high in six (PE:NPE=6:0), intermediate in one (PE), and low in seven (PE:NPE=1:6). Shifting was significantly more prominent in PE than in NPE cases (p<0.05). Peribronchovas-cular interstitial thickening was positive in all PE cases and one NPE case, with no positional shifting. CONCLUSION: Positional shifting of interlobular septal thickening to a gravity-dependent area, as demonstrated by HRCT, is the most specific indicator of pulmonary edema.