Jinna Kim

Pediatric diffusion tensor imaging: Normal database and observation of the white matter maturation in early childhood

Recent advances in diffusion tensor imaging (DTI) have made it possible to reveal white matter anatomy and to detect neurological abnormalities in children. However, the clinical use of this technique is hampered by the lack of a normal standard of reference. The goal of this study was to initiate the establishment of a database of DTI images in children, which can be used as a normal standard of reference for diagnosis of pediatric neurological abnormalities. Seven pediatric volunteers and 23 pediatric patients (age range: 0-54 months) referred for clinical MR examinations, but whose brains were shown to be normal, underwent anatomical and DTI acquisitions on a 1.5 T MR scanner. The white matter maturation, as observed on DTI color maps, was described and illustrated. Changes in diffusion fractional anisotropy (FA), average apparent diffusion constant (ADC(ave)), and T2-weighted (T2W) signal intensity were quantified in 12 locations to characterize the anatomical variability of the maturation process. Almost all prominent white matter tracts could be identified from birth, although their anisotropy was often low. The evolution of FA, shape, and size of the white matter tracts comprised generally three phases: rapid changes during the first 12 months; slow modifications during the second year; and relative stability after 24 months. The time courses of FA, ADC(ave), and T2W signal intensity confirmed our visual observations that maturation of the white matter and the normality of its architecture can be assessed with DTI in young children. The database is available online and is expected to foster the use of this promising technique in the diagnosis of pediatric pathologies.

Incidence of venous gas embolism during robotic-assisted laparoscopic radical prostatectomy is lower than that during radical retropubic prostatectomy

BACKGROUND Robotic-assisted laparoscopic radical prostatectomy (RALRP) is gaining popularity as a less traumatic and minimally invasive alternative to open radical retropubic prostatectomy (RRP). The aim of this study was to evaluate the incidence and grade of venous gas embolism (VGE) during RALRP compared with those during RRP using transoesophageal echocardiography (TOE). METHODS Fifty-two patients undergoing RRP (n=26) or RALRP (n=26) were consecutively enrolled. TOE was continuously applied during surgery and VGE was graded by an independent researcher. RESULTS The total incidence of VGE (proportion, 95% CI) in the RRP group was higher than that in the RALRP group [20/25 (0.80, 0.60-0.92) and 10/26 (0.38, 0.22-0.58), respectively]. Most VGE in the RALRP group occurred during the transection of the deep dorsal venous complex. There was no difference in the incidence of severe VGE between the two groups. No patients with cardiorespiratory instabilities even with severe VGE were observed in this study. CONCLUSIONS In contrast to general belief, VGE occurred less frequently during RALRP. Although the VGE in this study did not cause any cardiorespiratory instability, close monitoring for possibly fatal VGE must be considered during both types of radical prostatectomy because those who undergo radical prostatectomy frequently have cardiopulmonary co-morbidities.

Preoperative staging of papillary thyroid carcinoma: comparison of ultrasound imaging and CT.

OBJECTIVE The purpose of this study was to compare the diagnostic accuracy of ultrasound imaging with that of CT in the preoperative evaluation of primary tumors and cervical lymph nodes in patients with papillary thyroid carcinoma and to determine whether CT has greater diagnostic value than ultrasound alone in the care of these patients. MATERIALS AND METHODS The study population consisted of 299 consecutively registered patients with pathologically proven papillary thyroid carcinoma. The diagnostic accuracies of ultrasound, CT, and the combination of ultrasound and CT in the evaluation of primary tumors and lymph node metastasis were compared. We performed subgroup analysis to compare the findings on papillary thyroid microcarcinoma (10 mm in maximum diameter or smaller) with the findings on papillary thyroid carcinoma larger than 1 cm in maximum diameter. RESULTS Ultrasound was more accurate than CT in prediction of the presence of extrathyroidal tumor extension and of malignant disease in both thyroid lobes (p < 0.05) for overall lesions and for the two subgroups. In prediction of central node (neck level VI) metastasis, CT had greater sensitivity than ultrasound alone (p = 0.04) for overall lesions. Although the combination of ultrasound and CT had greater sensitivity than ultrasound alone in prediction of the presence of central node metastasis in the two subgroups, the sensitivity of the combination of ultrasound and CT did not reach statistical significance for papillary thyroid microcarcinoma. Ultrasound alone and ultrasound with CT had greater sensitivity than CT in prediction of lateral node (levels II-V) metastasis, but there was no significant difference in diagnostic value between ultrasound and the combination of ultrasound and CT for overall lesions or for the two subgroups (p > 0.05). CONCLUSION High-resolution ultrasound can be accurate in preoperative evaluation for extrathyroidal tumor extension and lateral lymph node metastasis. CT had greater sensitivity than ultrasound alone in the detection of central lymph node metastasis for all lesions. For papillary thyroid microcarcinoma, however, there was no significant difference in the diagnostic accuracy rates of ultrasound, CT, and the combination of ultrasound and CT.

Stent-assisted coil embolization of intracranial wide-necked aneurysms

The endovascular treatment of cerebral aneurysms with coils poses significant technical challenges, particularly with respect to wide-necked aneurysms. We present the results of our initial experiences in using a stent for endovascular treatment of aneurysms, with an emphasis on potential applications, technical aspects, and associated complications. Twenty-three wide-necked aneurysms from 22 patients were treated during the 13-month study period. Seven patients presented with subarachnoid hemorrhage. Aneurysms were located at the internal carotid artery (n=14), the vertebral artery (n=3), the basilar artery (n=5), and the middle cerebral artery (n=1). A Neuroform stent2 was used for stent-assisted procedures. Premedication with antithrombotic agents was available for unruptured cases. Postprocedural antithrombotic medication was prescribed for all patients. Nineteen aneurysms were primarily stented, followed by coil placement. For five of these aneurysms, stenting was performed subsequent to failure of an attempt to frame with an initial coil. Stenting for the remaining four aneurysms was performed as a rescue procedure to prevent the migration of previously placed coils. Complete occlusion was obtained in ten aneurysms, nearly complete occlusion (95% or more occluded) in 11 aneurysms, and partial occlusion (less than 95% occluded) in one aneurysm. In one aneurysm, we failed to navigate the microcatheter into the aneurysmal sac through the interstices of the stent. Stent thrombosis was noted during the procedure in one patient. Hemorrhagic complication on the 25th day after the procedure was noted in one patient. No procedure-related complications were observed during the procedure or during follow-up in the remaining 20 patients, including seven patients who did not receive antithrombotic agents prior to endovascular treatment owing to recent subarachnoid hemorrhage. To overcome the technical limitation in the coiling of wide-necked aneurysms, stent-assisted coil embolization may be a technically feasible and relatively safe method, even though longer periods of follow-up are required.

Relationship between Stress Urinary Incontinence and Pelvic Organ Prolapse

Abstract: We investigated the objective coexisting rate of stress urinary incontinence and pelvic organ prolapse, and also compared the treatment outcomes in patients who had both conditions, treated by a corrective operation on the basis of a precise preoperative evaluation. We reviewed 97 cases who underwent urodynamic studies and evaluation of the prolapse according to the Pelvic Organ Prolapse Quantification (POP-Q) system from among patients who were admitted for treatment of either stress urinary incontinence or pelvic organ prolapse. A Burch urethropexy, either alone or with a parvaginal repair, was done to correct the stress urinary incontinence, as well as additional operations to correct prolapse of stage II or more. The patients were evaluated postoperatively for the stress urinary incontinence and the degree of prolapse at every visit. Nineteen of 30 (63.3%) patients who were admitted with stress urinary incontinence had a coexisting pelvic organ prolapse, most often of the anterior wall. In 42 of 67 (62.7%) cases admitted with pelvic organ prolapse there was a coexisting stress urinary incontinence. A total of 61 patients who had both conditions were followed for 12 months postoperatively. The recurrence rate of stress urinary incontinence and prolapse (all of which were stage II) was 3.3% and 18.0%, respectively. It was noted that the greater the preoperative stage, the higher the recurrence rate (stage II 4.35%; stage III 25.0%; stage IV 33.6%). The coexisting rates of pelvic organ prolapse in patients having stress urinary incontinence, and stress urinary incontinence in patients having a pelvic organ prolapse, were both high. Therefore, when a preoperative evaluation that simultaneously considers both conditions and the correcting surgery is based on this evaluation, the recurrence rates of both conditions could be lowered.

Diffusion tensor MRI visualizes decreased subcortical fiber connectivity in focal cortical dysplasia

Diffusion tensor imaging (DTI) was applied to 12 patients with focal cortical dysplasia (FCD) in frontal or occipital cortex. Fiber tractography was obtained from seeding points in superior longitudinal fasciculus or posterior corona radiata. Mean fractional anisotropy of fiber bundles around the affected cortex was decreased in comparison to the contralateral hemisphere with statistical significance (paired t test, P = 0.0274). On visual analysis, tractography depicted decreased volume of fiber bundles connected to the dysplastic cortex invariably even in those with a normal T2 signal intensity of underlying white matter adjacent to FCD. DTI has high potential to be applied to localize the FCD and to provide a better understanding of the pathological changes in the white matter.

Detection of Thrombus in Acute Ischemic Stroke Value of Thin-Section Noncontrast-Computed Tomography

Background and Purpose— Previous studies on the hyperdense middle cerebral artery (MCA) sign were conducted using ≥5-mm thickness noncontrast-computed tomography (NCT). The purpose of this study was to compare thin-section NCT with 5-mm NCT in the detection of thrombus in acute ischemic stroke. Methods— Enrolled were consecutive 51 patients with acute infarction in the anterior or MCA territory. All patients underwent both 5-mm NCT and either 1.25- or 1-mm thin-section helical NCT within 6 hours of symptom onset. Patients were assigned to either the single or multisegmental occlusion group, depending on the thrombus extent on thin-section NCT. Thin-section NCT and 5-mm NCT were compared in the detection of thrombi. Results— Thrombi were identified in 45 patients (88%) on thin-section NCT and 16 on 5-mm NCT (31%; P<0.001). No occlusion was seen in 6 patients. Both sensitivity and specificity of thin-section NCT in detection of thrombus were 100%. Conclusions— Acute thrombus can be detected with higher sensitivity on thin-section NCT than on 5-mm NCT, and its extent is more accurately determined on thin-section NCT.

Surgical Treatment of Carotid Body Paragangliomas: Outcomes and Complications According to the Shamblin Classification

Objectives The objective of this study was to review our experience in the surgical management of carotid body paragangliomas and evaluate the outcomes and complications according to the Shamblin classification. Methods Thirteen patients who had been diagnosed and surgically treated for carotid body tumors (CBTs) were enrolled in this study. We reviewed patient demographics, radiographic findings, and surgical outcomes collected from medical records. Results Fifteen CBTs were found in 13 patients and 13 tumors were resected. Selective preoperative tumor embolization was performed on six patients. The median blood loss, operation time, and hospital stay for these patients were not significantly reduced compared to those without embolization. The median tumor size was 2.3 cm in Shamblin I and II and 4 cm in Shamblin III. The median intraoperative blood loss was 280 mL and 700 mL, respectively (P<0.05). Internal carotid artery ligation with reconstruction was accomplished on three patients (23%), and they all belonged to Shamblin III (38%). One Shamblin III patient (8%) developed transient cerebral ischemia, and postoperative stroke with death occurred in another Shamblin III patient. Postoperative permanent cranial nerve deficit occurred in three patients (23%) who were all in Shamblin III (P=0.03). There were no recurrences or delayed complications at the median follow up of 29 months. Conclusion Shamblin III had a high risk of postoperative neurovascular complications. Therefore, early detection and prompt surgical resection of CBTs will decrease surgical morbidity.

Alterations of white matter diffusion anisotropy in early deafness

To explore the effects of white matter in the absence of auditory input in the early deaf, we conducted a tract-based statistical analysis of the diffusion tensor anisotropy and the voxel-based morphometry in the white matter of 13 early deaf and 29 hearing individuals. Deaf individuals showed significant decreases in diffusion anisotropy and in regional volume reductions within the temporal white matter. Decreased anisotropy was also found at the internal capsule, superior longitudinal fasciculus, and the inferior frontal white matter. In contrast, the forceps major of the corpus callosum, where interhemispheric connections between visual cortices exist, showed increased anisotropy. We interpreted these white matter alterations in terms of both disuse-driven atrophy and compensatory plasticity in the early deaf.

Visualization of endolymphatic hydrops and correlation with audio-vestibular functional testing in patients with definite Meniere's disease

OBJECTIVES Visulization of endolymphatic hydrops has been reported using magnetic resonance imaging (MRI) in patients with Menieres disease. However, the relationship between the endolymphatic hydrops visualized by MRI and audio-vestibular functional tests have not been sufficiently investigated, such as pure tone audiometry (PTA), electrocochleography (EcoG), and vestibular evoked myogenic potential (VEMP). METHODS Here we attempted to visualize endolymphatic hydrops in patients with Menieres disease using 3Tesla (3T)-MRI following intratympanic gadolinium-diethylene-triamnie petaaetic acidbis (Gd-DTPA) injection and correlated the presence of hydrops with auditory testing. Following intratympanic Gd-DTPA contrast injections in 26 patients diagnosed as having definite Menieres disease, 3D-fluid-attenuated inversion recovery (3D-FLAIR) sequence imagings were performed. The PTA, EcoG, and VEMP testing was done bilaterally. Patients had typical results of auditory testing for Menieres disease. RESULTS The 3D-FLAIR MRI clearly demonstrated endolymphatic hydrops with signal voids in the cochlea (81%) and saccule (69%) in the definite Menieres disease group. Auditory tests verified that the visualized cochlear hydrops (basal turn) was correlated with a high tone hearing threshold in PTA and an abnormal EcoG. Though the absence of VEMP did not correlate with vestibular hydrops on MRI, large vestibular hydrops were detected by imaging. This study demonstrates that endolymphatic hydrops could be visualized by 3D-FLAIR MRI in Menieres disease patients. CONCLUSION Cochlea hydrops and vestibular (saccular) hydrops are readily visualized using these techniques. Hydrops, as visualized on MRI, may be a reliable means to diagnosis Menieres disease; this is supported by appropriate correlations with auditory vestibular functional testing.