Kyung-Pil Park

Phenotypic variability in Kennedy's disease: implication of the early diagnostic features

Objectives –  The clinical diagnosis of Kennedys disease (KD) is not easy when the typical manifestations are lacking, especially in early stage of the disease. In our study, we tried to identify the relative frequency of common clinical features and early symptoms in KD.

Change in Cortical Vessel Signs on Susceptibility-Weighted Images after Full Recanalization in Hyperacute Ischemic Stroke

Background: The cortical vessel signs (CVSs) on susceptibility-weighted images (SWIs) have been reported in patients with hyperacute ischemic stroke. We evaluated the change of this susceptibility sign on the immediate SWI after full recanalization and its clinical implications. Methods: Nineteen hyperacute ischemic stroke patients who had acute large artery occlusion and underwent post-recanalization SWI were enrolled in this study. The patients had ICA (internal carotid artery, 2 cases), M1 (M1 segment of middle cerebral artery, 7 cases), M2 (M2 segment of middle cerebral artery, 1 cases), T (intracranial ICA bifurcation, 2 cases), ICA/M1 (4 cases) and basilar artery (3 cases) occlusion on imaging studies before thrombolysis and they underwent immediate magnetic resonance imaging, including the SWI, after full recanalization. The recanalization status was evaluated using the thrombolysis in cerebral infarction (TICI) score before and after thrombolysis. The SWI images were evaluated for the presence of asymmetry of veins over the ischemic territory and this was correlated with the site of stenosis or occlusion. The veins in the ischemic territory were classified as ‘prominent’ if there were more numerous veins and/or large veins with a greater signal loss observed compared with the opposite normal hemisphere, ‘equal’ if there were no significant difference in appearance in both the cerebral hemispheres, and ‘less’ if the veins were decreased in the affected area as compared with that of the normal cortex. Baseline clinical parameters and clinical outcomes were reviewed. Results: The initial TICI grades were 0 in all cases. After thrombolysis, TICI grades were 3 in all cases. The pre-recanalization SWIs were obtained in 10 of 19 patients and all 10 showed prominent CVSs over the affected side, which disappeared on the post-recanalization SWI. On the post-recanalization SWI, the observed veins in the affected area were equal (10/19), less (5/19), and both equal and less (4/19). Patients with equal cortical veins in the affected area had small lesions on diffusion-weighted image (DWI) (10/19), while patients with less cortical veins had medium to large lesions on DWI (9/19). Conclusion: The prominent CVSs on SWI can be indicative of acute thromboembolic occlusion and its change immediately after recanalization can be used to reflect the metabolic status. After recanalization, the appearance of the equal CVS (return to normal) on SWI was associated with a favorable clinical outcome and infarction was avoided in our small series study.

Intracranial solitary fibrous tumors: imaging findings in 6 consecutive patients.

BACKGROUND AND PURPOSE: Intracranial solitary fibrous tumors (ISFTs) are rare mesenchymal neoplasms originating in the meninges. The aim of this study was to describe the CT, MR imaging, and angiographic features of the solitary fibrous tumor and to identify imaging characteristics. MATERIALS AND METHODS: We retrospectively reviewed CT, MR, and angiographic findings in 6 cases of ISFT. We evaluated the size, shape, and location of the tumor; the internal content and margin of the lesion; the pattern of enhancement; and the change of the adjacent structures. Density on noncontrast CT scans, signal intensity on MR images, and angiographic features were also documented. RESULTS: Each lesion appeared as a discrete extra-axial mass (size, 3–7 cm; mean, 5 cm). Five lesions were entirely solid, and 1 had peritumoral cyst. All 5 of the noncontrast CT scans showed hyperattenuated masses, and the tumors exhibited marked heterogeneous enhancement. No lesion contained calcification, and 2 cases showed bone invasions. On the MR images, 4 lesions showed mixed signal intensity on T2-weighted imaging. All of the lesions revealed marked heterogeneous enhancement. All of the tumors had thickening of the meninges adjacent to the tumor. Angiography showed delayed tumor blushing in all, and 3 of them had dysplastic dilation of the tumor vessels. CONCLUSION: Although there are no pathognomonic imaging findings, some imaging features, such as the “black-and-white mixed” pattern on T2-weighted images and marked heterogeneous enhancement, might be helpful in the diagnosis of intracranial solitary fibrous tumor.

Multiple Hypointense Vessels on Susceptibility-Weighted Imaging in Acute Ischemic Stroke: Surrogate Marker of Oxygen Extraction Fraction in Penumbra?

Background: Multiple hypointense vessels (MHV) on susceptibility-weighted imaging (SWI) are frequently observed in patients with acute cerebral ischemia, but their implication has not been clearly established. To elucidate the clinical significance of MHV on SWI, we investigated the association of MHV on SWI with clinical data and other MR markers in patients with acute ischemic stroke. Methods: We enrolled acute stroke patients with internal carotid or proximal middle cerebral artery occlusion who underwent MRI including SWI within 3 days from stroke onset. Baseline clinical data were reviewed. Stroke severity was measured by the National Institutes of Health Stroke Scale (NIHSS). We graded the degree of MHV on SWI as four groups of none, subtle, relative, or extensive by the modified Alberta Stroke Program Early CT Scan (ASPECTS) system. To evaluate the degree of collateral flow, distal hyperintense vessels (DHV) on FLAIR and vessels on post-contrast time-of-flight MR angiography (TOF MRA) source images were graded respectively as 3 groups: none/subtle/prominent and poor/moderate/good. Diffusion and perfusion lesion volume and diffusion-perfusion mismatch (DPM) ratio were measured in all patients. We analyzed the association of the degree of MHV on SWI with clinical data and MR markers. Results: Eighty patients were included in the study. The mean MR time from stroke onset was 12.4 h (range 0.5-63.0). There is no difference in MR time from stroke onset between groups of MHV on SWI. MHV were observed in 68 (85%) of 80 patients: none in 12, subtle in 11, relative in 13, and extensive in 44. There were no statistically significant associations between MHV on SWI and vascular risk factors. Patients with more extensive MHV on SWI had a smaller diffusion volume (p < 0.001), larger DPM (p < 0.001), and lower initial NIHSS scores (p = 0.022). Prominent DHV was presented in 29 of 44 patients with extensive MHV (p < 0.001). Good collateral flow on TOF MRA source images was presented in 37 of 44 patients with extensive MHV (p < 0.001). Conclusions: More extensive MHV on SWI in acute ischemic stroke is associated with lower initial NIHSS scores, smaller diffusion lesion volume, better collateral flow, and larger DPM. Our results show the possibility that MHV on SWI may be a useful surrogate marker for predicting increased oxygen extraction fraction and diffusion-perfusion mismatch in acute ischemic hemisphere.

Susceptibility-Weighted Imaging for Detection of Thrombus in Acute Cardioembolic Stroke

Background and Purpose Susceptibility-weighted imaging (SWI) can show an intravascular thrombus as a hypointense susceptibility vessel sign (SVS). In this study, we investigated the usefulness of SWI in the detection of an intravascular thrombus in acute cardioembolic stroke by comparing the SVS on SWI to the vessel status on time-of-flight magnetic resonance angiography (MRA). Methods We consecutively enrolled patients with cardioembolic stroke in the anterior circulation within 3 days from stroke onset. The frequency and location of the SVS on SWI were compared with those of occlusion on MRA. Results One hundred and twenty-two patients were conclusively enrolled in this study. The SVS was observed in 75.4% (92/122) of the enrolled patients. MRA showed occlusion in 57% (70/122) of the enrolled patients. The SVS was identified in all 70 patients with occlusion on MRA. The SVS was observed in 22 (42.3%) of 52 patients without occlusion on MRA (P<0.001), which was identified mainly in post-bifurcation segments of the middle cerebral artery: the M2 segment in 4 patients, M3 segment in 10 patients, M4 segment in 4 patients, A3 segment in 1 patient, and multiple segments in 2 patients. The mean length of the SVS in the M1 segment was 13.65 mm (median: 12.39 mm, length range: 2.70–39.50 mm). Conclusions SWI can provide useful information about the thrombus location, the presence of a single thrombus or multiple thrombi especially in distal intracranial arteries, and the thrombus burden, all in acute cardioembolic stroke.

Diffusion-weighted imaging of intramural hematoma in vertebral artery dissection

BACKGROUND AND PURPOSE Dissections of the carotid and vertebral arteries can be detected by several imaging modalities, but there is yet no consensus on the most efficient and effective choice. METHODS We performed diffusion-weighted imaging (DWI) in four patients with vertebral artery dissection documented with T2- and T1-weighted axial magnetic resonance imaging (MRI), and conventional angiography. Intervals from the onset of headache to evaluation ranged from one day to two weeks. RESULTS All the patients showed high signal intensity within the affected vertebral artery on DWI. CONCLUSION The movements of water molecules are more or less restricted within the clots according to the stage of thrombus formation in arterial dissection. Our study may provide another potential imaging method in the difficult task of proving arterial dissection.

SLC25A4 and C10ORF2 Mutations in Autosomal Dominant Progressive External Ophthalmoplegia.

Background and Purpose Progressive external ophthalmoplegia (PEO) with Mendelian inheritance is a heterogeneous group of diseases associated with multiple deletions of mitochondrial DNA (mtDNA), which results from the disturbed replication and maintenance of mtDNA secondary to the mutations of nuclear genes including POLG, SLC25A4, C10ORF2, POLG2, OPA1, and RRM2B. The aim of this study was to identify the genetic defects underlying the pathology and clinical features in two Korean kindreds with autosomal dominant PEO. Methods Two pathologically proven PEO patients with a clear autosomal dominant pattern of inheritance were selected. To exclude a large-scale rearrangement, a long-range polymerase chain reaction (PCR) was performed using DNA extracted from biopsied muscle tissue taken from each patient. All coding regions and exon-intron boundaries of POLG, SLC25A4, C10ORF2, and POLG2 were amplified by PCR and directly sequenced. Results One patient showed multiple deletions of mtDNA on long-range PCR analysis, and two known heterozygous missense mutations in SLC25A4 (p.Asp104Gly) and C10ORF2 (p.Glu479Lys) were identified in each patient. The p.Asp104Gly mutation in SLC25A4 was identified in the patient with an early onset, slowly progressive, pure PEO phenotype, while the p.Glu479Lys mutation in C10ORF2 was identified in the other patient, with a late-onset disease and PEO plus phenotype. Conclusions Two mutations affecting nuclear genes were identified in Korean patients with autosomal dominant PEO. Further studies are necessary to identify the clear pathogenetic mechanisms and establish genotype-phenotype correlations in autosomal dominant PEO.

Hemimacropsia after medial temporo-occipital infarction

Dysmetropsia is a disorder of visual perception characterised by an apparent modification of the size of perceived objects.1–3 Objects can appear larger (macropsia) or smaller (micropsia) than their actual size. Dysmetropsia can result from retinal oedema causing a dislocation of the receptor cells and from lesions affecting other parts of extracerebral visual pathways. Transient micropsia can also result from epileptic seizure, migraine, infectious mononucleosis, the action of mescaline and other hallucinogenic drugs, and psychopathological phenomena. Permanent dysmetropsia following focal cerebral lesions is rare. Most of the prior reports described hemimicropsia due to lesions mainly involving the lateral aspect of the visual association cortex.1–3 However, reports of hemimacropsia following focal cerebral lesions have been extremely rare1,4 and hemimacropsia following a focal vascular lesion has not been described previously. We describe a patient with left hemimacropsia due to right medial temporo-occipital infarction. A 64-year-old right-handed man with hypertension was admitted 4 days after a sudden onset of visual disturbance. He …

Neuroanatomical correlation of urinary retention in lateral medullary infarction

We prospectively recruited 10 patients who presented with urinary retention as a neurological deficit that was attributable to lateral medullary infarction. Of these, 9 patients underwent a urodynamic study, which demonstrated detrusor underactivity of the bladder in 7 patients. Urinary retention developed mainly when the lesions involved the lateral tegmentum of the middle or caudal medulla. We concluded that interruption of the descending pathway from the pontine micturition center to the sacral spinal cord in the lateral medulla was responsible for the development of urinary retention. Ann Neurol 2015;77:726–733

Effects of retinoic acid on ischemic brain injury-induced neurogenesis

Neurogenesis can be induced by pathological conditions such as cerebral ischemia. However the molecular mechanisms or modulating reagents of the reactive neurogenesis after the cerebral ischemia are poorly characterized. Retinoic acid (RA) has been shown to increase neurogenesis by enhancing the proliferation and neuronal differentiation of forebrain neuroblasts. Here, we examined whether RA can modulate the reactive neurogenesis after the cerebral ischemia. In contrast to our expectation, RA treatment decreased the reactive neurogenesis in subventricular zone (SVZ), subgranular zone (SGZ) and penumbral region. Furthermore, RA treatment also decreased the angiogenesis and gliosis in penumbral region.