Voxel-Wise Analysis of Diffusion Tensor Imaging for Clinical Outcome of Cochlear Implantation: Retrospective Study

OBJECTIVES: To evaluate retrospectively, the possible difference in diffusion tensor imaging (DTI) metric of fractional anisotropy (FA) between good and poor surgical outcome cochlear implantation (CI) patients using investigator-independent voxel-wise analysis. METHODS: Eighteen patients (11 males, 7 females; mean age, 5.9 years) with profound sensorineural hearing loss underwent DTI scans using a 3.0 Tesla magnetic resonance scanner. Among the 18 patients, 10 patients with categories of auditory performance (CAP) score over 6 were classified into the good outcome group and 8 patients with CAP score below 6 were classified into the poor outcome group. The diffusion tensor scalar measure was calculated from the eigenvalues of the tensor on a voxel-by-voxel basis from each subject and two-sample t-test evaluation between good and poor outcome subjects were performed for each voxel of FA values, across the entire brain, with a voxel-wise intensity threshold of P<0.0005 (uncorrected) and a contiguous cluster size of 64 voxels. Individual values of FA were measured by using the region-of-interest based analysis for correlation analysis with CAP scores, open sentence and open word scores. RESULTS: Two-sample t-test evaluation using SPM voxel-wise analysis found significantly higher FA values at the several brain areas including Broca's area, genu of the corpus callosum, and auditory tract in good outcome subjects compared to poor outcome subjects. Correlation analyses between FA and CAP scores, open sentence and open word scores revealed strong correlations at medial geniculate nucleus, Broca's area, genu of the corpus callosum and auditory tract. CONCLUSION: Investigator-independent voxel-based analysis of DTI image demonstrated that good outcome subjects showed better neural integrity at brain areas associated with language and auditory functions, suggesting that the conservation of microstructural integrity of these brain areas is important. Preoperative functional imaging may be helpful for CI.

Construction of a DNA Chip for Screening of Genetic Hearing Loss

OBJECTIVES: Hearing loss is the most common sensory disorder in humans and genetic causes are estimated to cause more than 50% of all incidents of congenital hearing loss. To develop an efficient method for a genetic diagnosis of hearing loss, we have developed and validated a genetic hearing loss DNA chip that allows the simultaneous analysis of 7 different mutations in the GJB2, SLC26A4, and the mtDNA 12S rRNA genes in Koreans. METHODS: A genotyping microarray, based on the allele-specific primer extension (ASPE) method, was used and preliminary validation was examined from the five patients and five controls that were already known their genotypes by DNA sequencing analysis. RESULTS: The cutoff Genotyping index (GI) of genotyping for each mutation was set up and validated to discriminate among the genotypes. The result of the DNA chip assay was identical to those of previous results. CONCLUSION: We successfully designed the genetic hearing loss DNA chip for the first time in Korea and it would be useful for a clinical genetic diagnosis of hearing loss. Further consideration will be needed in order to examine the accuracy of this DNA chip with much larger patient sample numbers.

The Significance of Radiologic Positive Finding of Paranasal Sinus in Bone Marrow Transplant Patients

BACKGROUND: Bone marrow transplantation (BMT) is a beneficial and curative technique used in different hematologic conditions or malignant neoplastic diseases. However, bone marrow transplant patients are at a higher risk of developing infections and complications due to previous chemotherapy, radiotherapy, immunosuppression, antibiotics therapy, multiple viral infections, and GVHD (graft-versus-host disease). OBJECTIVES: The purpose of this study is to determine the prevalence and clinical data of rhinosinusitis among patients with BMT. We also investigated whether pre-BMT positive radiologic finding could predispose patients to the development of post-BMT rhinosinusitis or not. MATERIALS AND METHODS: We reviewed the records of 203 patients who had received BMT in Kyungpook National University's hospital from September 1998 to August 2006. RESULT: Sixteen patients (7.8%) had radiologic positive finding before BMT. Fifteen patients had no sinonasal symptoms and did not get any treatment. Only one patient had rhinosinusitis so that BMT was delayed and treated with antibiotics. Among these patients, one patient got newly developed rhinosinusitis after BMT. After BMT, sinusitis developed in ten patients (4.9%), including one patient who had invasive fungal sinusitis. Our study revealed a higher incidence of rhinosinusitis among allogenic BMT patients than among autologous BMT patients. The most common symptoms and signs were fever. Only one patient complained of typical sinonasal symptoms. CONCLUSION: Even though the prevalence of rhinosinusitis is low (4.9%) among post-BMT patients, maintenance of a high index of suspicion among these patients is necessary because sinonasal symptoms and signs are generally minimized after BMT. The study concluded that pre-BMT positive radiologic findings without sinonasal symptoms is unlikely to develop post-BMT rhinosinusitis.

Endoscopic Repairment of Septal Perforation with Using a Unilateral Nasal Mucosal Flap

OBJECTIVES: Nasal septal perforation is an anatomic defect of the cartilaginous and bone tissues of the nasal septum. Many approaches and techniques to repair nasal septal perforations have been reported on. The purpose of this paper is to report on our surgical technique and the results of the treatment for nasal septal perforations. METHODS: From May 2001 to March 2008, 14 patients (12 males and 2 females; mean age: 41.3 yr) were enrolled. The mean perforation size was 15 mm, and all the perforations were located at the cartilaginous portion. Our surgical technique is based on an endoscope-assisted endonasal approach, with dissection of unilateral advanced mucosal flaps with using a temporalis fascia graft. The follow-up periods ranged from 3 to 23 months (mean follow-up period: 8 months). RESULTS: Using our surgical technique on 14 patients, 12 cases (85.7%) of septal perforation were closed without complication. The remaining two patients (14.3%) had incomplete closures (about 2-3 mm) without any significant symptoms related to the remaining perforation. CONCLUSION: Our technique is a viable procedure with a high success rate for achieving closure of nasal septal perforations. It has the advantages of shortening the operative time, no external incision and avoiding any other perforation during the operation. Therefore, we consider it to be a good alternative for repairing nasal septal perforations.