Findings of Intravenous Gadolinium Inner Ear Magnetic Resonance Imaging in Patients With Acute Low-Tone Sensorineural Hearing Loss

Objectives@#Acute low-tone sensorineural hearing loss (ALHL) is thought to have a different etiology from that of idiopathic sudden sensorineural hearing loss. We hypothesized that endolymphatic hydrops (EH) in the inner ear organ contributes to ALHL, even in patients without vertigo. This study investigated the presence of EH in ALHL and compared the clinical characteristics of patients with or without EH. @*Methods@#We retrospectively reviewed 38 patients diagnosed with ALHL without vertigo from January 2017 to March 2022. EH was measured in all patients using inner ear magnetic resonance imaging (MRI). In addition, we selected patients who showed only mid- or high-frequency hearing loss and had available MRI data as a control group and compared the ALHL and control groups. @*Results@#After treatment, the pure-tone average at low frequencies significantly improved compared to the initial hearing (P<0.001). Hearing recovery was observed in 63.1% of patients; however, the recovery rate did not differ based on the treatment method. During the follow-up period, six patients (15.8%) progressed to Meniere’s disease, and 18 (47.4%) experienced recurrence. In the ALHL group, the cochlear hydrops ratio on the affected side (0.34±0.09) was significantly higher than on the contralateral side (0.29±0.12) (P=0.005), and most patients showed hydrops in the apex area of the cochlea. Compared with the control group (0.25±0.15), the ALHL group showed a significantly higher cochlear hydrops ratio (P=0.043). The correlation analysis showed a tendency for hearing thresholds at low frequencies to increase as the hydrops ratio increased, albeit without statistical significance. @*Conclusion@#The cochlear hydrops ratio, especially in the apex area on the affected side, was significantly higher in patients with ALHL, suggesting that EH in the cochlea contributes to the pathogenesis of ALHL.

Imaging of Facial Nerve With 3D-DESS-WE-MRI Before Parotidectomy: Impact on Surgical Outcomes

Objective@#The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state waterexcitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI. @*Materials and Methods@#This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESSWE-MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors. @*Results@#The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESSWE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64–8.25] and 2.02 [95% CI: 0.32–12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19–16.75] and 1.94 [95% CI: 0.20–18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001). @*Conclusion@#Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.

Normal Anatomy of Cranial Nerves III–XII on Magnetic Resonance Imaging

Because of the inherent complex anatomy and functional arrangement of the cranial nerves (CNs), neuroimaging of cranial neuropathy is challenging. With recent advances in magnetic resonance imaging (MRI) techniques, the cause of cranial neuropathy can now be detected in many cases. As an active multidisciplinary team member of cranial neuropathy, it is essential for the neuroradiologist to be familiar with the detailed anatomy of the CNs on MRI. This review contains the basic MRI anatomy of CNs III–XII according to a segmental classification from the brain stem to the extracranial region. The optimal imaging options to best evaluate the specific segment of the CNs will also be discussed briefly.

Microarray Analysis in Spontaneously Hypertensive Rat Heart after Losartan Treatment / 이화의대지

OBJECTIVES: Spontaneously hypertensive rats (SHR) are frequently used as rat models of essential hypertension. The mechanism for the development of hypertension is complicated and it is unknown. The renin-angiotensin system (RAS) plays a key role in the control of blood pressure. Microarrays are a powerful tool for studying genetics. The purpose of this study was to investigate changes of gene expression in the heart tissues of SHR after losartan treatment to provide basic data that is useful in the early diagnosis of hypertension and gene treatment. METHODS: Rats were divided into three groups: the control (C) group; the hypertension (H) group (SHR), and the losartan (L) group; treated with losartan (10 mg/kg/day) in SHR. Rats were sacrificed at week 5 and microarray analysis was performed. RESULTS: 102 gene expressions including the genes associated with cell proliferation such as Raf1, Uchl1, Btla, Spock1 were increased. The other 139 gene expressions, including the genes related to the regulation of metabolism such as TFIID, Auf1, Bmp, Hub, Taf51 showed decreases in gene expression. A total of 31 genes were differentially expressed in the L group compared to the H group. Of these, 16 genes including the genes associated with macromolecule metabolism such as MGC105766, Ppp1r1a, Rpl3l showed increased expression. The other 15 genes including the genes associated with primary metabolism such as Mcpt4, Ngn3, Tdo, Ak2 Hyal2 showed decreased expressions. CONCLUSION: According to microarray analysis, there was significant gene expression change in SHR compared with normal rats as well as significant gene expression changes after losartan treatment in SHR.