Morphometric Analysis of Temporal Bone Radiology for Cochlear Implant Candidacy.

Cochlear Implantation (CI) is a well-accepted treatment for severe-to-profound sensorineural hearing loss, refractory to conventional hearing amplification. Pre-operative Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) play pivotal roles in patient selection to rule out findings that preclude surgery or identify conditions that may impact the surgical procedure. A prospective study was carried out in a tertiary care center over three years, from January 2020 to January 2023. One hundred and ninety (380 ears) patients' High-Resolution Computed Tomography (HRCT) studies of the temporal bone and MRI scans of the auditory pathways were analyzed. A reporting format was followed which was devised by a team of senior implant surgeons and senior neuro-radiologists. Our study aims to provide a comprehensive radiologic protocol for CI candidacy including normative data for the essential morphometrics in the Indian setting.

Widening the clinical, radiological and genetic spectrum of autosomal recessive ataxia of Charlevoix-Saguenay in Indian patients.

BACKGROUND: Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), classically presenting as a triad of early-onset cerebellar ataxia, lower extremity spasticity and peripheral neuropathy, is caused by mutations in SACS gene which encodes the protein sacsin. OBJECTIVE: To provide new insight into the occurrence of SACS mutations in South India. METHODS: Patients with three cardinal features of ARSACS-peripheral neuropathy, cerebellar ataxia, and pyramidal tract signs were included. Nine patients were clinically identified and genetically evaluated. Mutation screening of SACS by targeted sequencing of 40 recessive ataxia genes panel by next-generation sequencing was conducted. Additional investigations included magnetic resonance imaging (MRI), fundoscopy, optical coherence tomography (OCT) and nerve conduction studies (NCS). Functional disability was assessed by the Spinocerebellar Degeneration Functional Score. RESULTS: Two hundred and fifteen cerebellar ataxia patients were screened, and 9 patients with cerebellar ataxia with spasticity, peripheral neuropathy and MRI brain characteristics, consistent with a clinical diagnosis of ARSACS were identified, of which 7 patients were identified to have mutation in the SACS gene and are detailed hereafter. Age of presentation ranged from 20 to 55 years (29.8 ± 11.9) with a mean disease duration of 12.7 years (SD-7.65, range 5-22 years). All except one had onset of symptoms in the form of an ataxic gait noticed before 20 years of age. Additional features were subnormal intelligence (4/7), slow and hypometric saccades (1/7), seizures (1/7), kyphoscoliosis (1/7) and dysmorphic facies (1/7). SDFS was 3 in 5/7 patients signifying moderate disability with independent ambulation. MRI showed cerebellar atrophy with predominant atrophy of the superior vermis (7/7), horizontal linear T2 hypointensities in the pons(7/7), hyperintensities where lateral pons merges with the middle cerebellar peduncle (MCP) (7/7) well seen in fluid-attenuated inversion recovery (FLAIR) images, thickening of MCP (3/7), symmetric lateral thalamic hyperintensities (6/7), posterior fossa arachnoid cyst (4/7),thinning of posterior mid-body of corpus callosum (7/7), marginal mineralisation of the basal ganglia (7/7), bilateral parietal atrophy (7/7) and thinning of corticospinal tract on diffusion tensor imaging (DTI) (7/7). We identified pathogenic homozygous frameshift mutations in the SACS gene in six patients (including two siblings), while one patient had a heterozygous pathogenic deletion. CONCLUSIONS: This is the largest series of genetically confirmed ARSACS patients from India highlighting the clinical, ophthalmological, imaging and genetic features of this cohort.

Spontaneous Intracranial Hypotension: A Review of Neuroimaging and Current Concepts.

Spontaneous intracranial hypotension (SICH) is the emerging cause of orthostatic headache as it has been better recognized in recent years. SICH happens due to spinal cerebrospinal fluid (CSF) leak; however, the manifestations are predominantly cranial and hence imaging in SICH includes brain and spine. There are few characteristic brain imaging features to be concerned about to diagnose SICH in patients with vague symptoms or low clinical suspicion. Spine screening is recommended in these patients to assess spinal CSF leaks. While neuroradiologists play a significant role from the time of diagnosis to treatment of SICH, there is a need for all the general radiologists to be aware of the condition. Computed tomography myelogram and digital subtraction myelogram are performed for diagnostic and therapeutic management of SICH. There is a known risk for SICH recurrence in patients with sagittal longitudinal epidural collection and hence, targeted blood patch should be used instead of blind patch. Most importantly, slow mobilization is recommended following the patch to avoid recurrence.

Igg4 Related Disease of Skull Base-A Diagnostic Challenge.

IgG4 related disease (IgG4-RD) is a fibro-inflammatory disease, with tendency to affect any organ of the body. However, few cases affecting the skull base have been reported in literature. We report one such case in an elderly male, who presented us with a mass lesion in the skull base that mimicked nasopharyngeal malignancy. On thorough clinical history, examination, and investigations, IgG4 Related disease was diagnosed and treatment was started for it. The patient responded well to the treatment and is on follow up.

Coronavirus Disease 2019 (COVID-19)-Associated Rhino-Orbito-Cerebral Mucormycosis: A Multi-Institutional Retrospective Study of Imaging Patterns.

BACKGROUND: Mucormycosis infection of the maxillofacial region and brain has been associated with coronavirus disease 2019 (COVID-19) infection. Mucormycosis was relatively a rare infection before COVID-19, and imaging findings are not very well described. MATERIALS AND METHODS: A retrospective imaging study of 101 patients diagnosed with COVID-19-associated mucormycosis by histopathology and/or culture was performed. All patients underwent computed tomography and/or magnetic resonance imaging based on the clinical condition of the patient and on consensus decision by the team of treating physicians. A simple 3-stage classification system based on imaging findings was adopted. RESULTS: One hundred one cases were included in the final analysis (mean age = 55.1 years; male/female ratio = 67:34). The affected patients had diabetes in 94% of the instances (n = 95), 80.1% (n = 81) received steroids), whereas 59.4% (n = 60) patients received supplemental oxygen. The majority underwent surgical intervention, whereas in 6 cases, patients were treated with antibiotic regimens. Sixty subjects improved following therapy, whereas 18 eventually succumbed to the illness. We noted a significant positive correlation between the imaging stage and outcomes. No association was seen between other clinical parameters and final clinical outcomes. Salient imaging findings include lack of normal sinonasal mucosal enhancement, perisinus inflammation, ischemic optic neuropathy, perineural spread, pachymeningeal enhancement, and presence of strokes. CONCLUSIONS: We describe the imaging findings in the largest cohort of patients with rhino-orbito-cerebral mucormycosis in the context of the current COVID-19 pandemic. A simplified staging system described here is helpful for standardized reporting and carries prognostic information.

Giant Facial Nerve Schwannoma with Extra-Temporal Involvement: A Series Of Two Cases.

Facial nerve schwannoma is a rare benign tumor of temporal bone arising from the schwann cells with incidence of 0.8%. They can arise from any segment of facial nerve with geniculate ganglion being the most common and labyrinthine segment the second commonest site. Intra-temporal location is common while only 9% of the cases have extra-temporal or parotid gland involvement. Bony remodeling or scalloping of the facial canal and the surrounding bone is the classic radiological feature of schwannoma. However schwannomas of temporal bone location can show bony erosions. The management option depends on site, extent, facial nerve function and hearing status. Surgery is reserved for large tumors with poor facial functions, hearing loss and giddiness. Giant facial nerve schwannoma with extra-temporal involvement is a rare entity with only handful number of cases reported in the literature. We present a series of two cases of giant facial nerve schwannoma with parotid gland involvement.

Interobserver Variation in Response Evaluation Criteria in Solid Tumors 1.1.

PURPOSE: Response Evaluation Criteria in Solid Tumors (RECIST 1.1) is the gold standard for imaging response evaluation in cancer trials. We sought to evaluate consistency of applying RECIST 1.1 between 2 conventionally trained radiologists, designated as A and B; identify reasons for variation; and reconcile these differences for future studies. METHODS: The study was approved as an institutional quality check exercise. Since no identifiable patient data was collected or used, a waiver of informed consent was granted. Imaging case report forms of a concluded multicentric breast cancer trial were retrospectively reviewed. Cohen's kappa was used to rate interobserver agreement in Response Evaluation Data (target response, nontarget response, new lesions, overall response). Significant variations were reassessed by a senior radiologist to extrapolate reasons for disagreement. Methods to improve agreement were similarly ascertained. RESULTS: Sixty one cases with total of 82 data-pairs were evaluated (35 data-pairs in visit 5, 47 in visit 9). Both radiologists showed moderate agreement in target response (n = 82; ĸ = 0.477; 95% confidence interval [CI]: 0.314-0.640-), nontarget response (n = 82; ĸ = 0.578; 95% CI: 0.213-0.944) and overall response evaluation in both visits (n = 82; ĸ = 0.510; 95% CI: 0.344-0.676). Further assessment demonstrated "Prevalence effect" of Kappa in some cases which led to underestimation of agreement. Percent agreement of overall response was 74.39% while percent variation was 25.6%. Differences in interpreting RECIST 1.1 and in radiological image interpretation were the primary sources of variation. The commonest overall response was "Partial Response" (Rad A:45/82; Rad B:63/82). CONCLUSION: Inspite of moderate interobserver agreement, qualitative interpretation differences in some cases increased interobserver variability. Protocols such as Adjudication, to reduce easily avoidable inconsistencies are or should be a part of the Standard Operating Procedure in imaging institutions. Based on our findings, a standard checklist has been developed to help reduce the interpretation error-margin for future studies. Such check-lists may improve interobserver agreement in the preadjudication phase thereby improving quality of results and reducing adjudication per case ratio. CLINICAL RELEVANCE: Improving data reliability when using RECIST 1.1 will reflect in better cancer clinical trial outcomes. A checklist can be of use to imaging centers to assess and improve their own processes.

The Imaging of Localization Related Symptomatic Epilepsies: The Value of Arterial Spin Labelling Based Magnetic Resonance Perfusion.

Accurate identification of the epileptogenic zone is an important prerequisite in presurgical evaluation of refractory epilepsy since it affects seizure-free outcomes. Apart from structural magnetic resonance imaging (sMRI), delineation has been traditionally done with electroencephalography and nuclear imaging modalities. Arterial spin labelling (ASL) sequence is a non-contrast magnetic resonance perfusion technique capable of providing similar information. Similar to single-photon emission computed tomography, its utility in epilepsy is based on alterations in perfusion linked to seizure activity by neurovascular coupling. In this article, we discuss complementary value that ASL can provide in the evaluation and characterization of some basic substrates underlying epilepsy. We also discuss the role that ASL may play in sMRI negative epilepsy and acute scenarios such as status epilepticus.

Arterial spin labeling hyperperfusion in Rasmussen's encephalitis: Is it due to focal brain inflammation or a postictal phenomenon?

BACKGROUND AND PURPOSE: The study evaluated the utility of arterial spin labeling (ASL) perfusion imaging in Rasmussen's encephalitis (RE). MATERIAL AND METHODS: The hospital electronic database was searched using the search words "encephalitis," "autoimmune encephalitis" and "Rasmussen's encephalitis" for the period of 1 Jan 2015 to 31 Jan 2017. Clinically diagnosed cases of RE for which epilepsy protocol magnetic resonance imaging (MRI) with perfusion imaging (ASL) performed on a 3T scanner were retrieved. The diagnosis of RE was based on Bien's criteria (Bien et al., 2005). We obtained patient's demographic details, clinical features, electrophysiological studies, and follow-up data from electronic hospital records. RESULTS: We included nine patients with RE of whom seven patients showed increased perfusion, and two patients decreased perfusion. Among these patients, MRI changes of gyral hyperintensity without volume loss corresponded to regional ASL hyperperfusion in six patients and ASL hypoperfusion in one patient. Two patients who showed ASL hypoperfusion had corresponding atrophy on MRI. Eight patients of RE had epilepsia partialis continua (EPC) or daily seizures, and one patient was seizure-free post-surgery. Five patients showed a concordance of ASL hyperperfusion with clinical ictal onset zone. Among the seven patients with ASL hyperperfusion, the finding was concordant (complete or partial) with the electroencephalogram (EEG) ictal onset zone in six patients and with interictal epileptiform discharges (IED) in seven patients. CONCLUSION: Increased perfusion in ASL of the involved brain parenchyma in RE is a common MRI finding and may be due to either active inflammation of the brain involved or a seizure-related finding.

Utility of mobile devices in the computerized tomography evaluation of intracranial hemorrhage.

AIM: To evaluate the utility of a mobile device to detect and assess intracranial hemorrhage (ICH) on head computed tomographys (CT) performed in the emergency setting. MATERIALS AND METHODS: 100 head CT scans were randomly selected from our emergency radiology database and anonymized for patient demographics and clinical history. The studies were independently interpreted by two experienced radiologists in a blinded manner, initially on a mobile device (iPad, Apple computers) and subsequently, at an interval of one week, on a regular desktop workstation. Evaluation was directed towards detection, localization and characterization of hemorrhage. The results were assessed for accuracy, sensitivity, specificity and positive predictive value. Statistical significance was ascertained using Fisher's exact test. RESULTS: 27 of the examinations were positive for ICH, of which 11 had multiple hemorrhages. Of these there were 17 subdural, 18 intraparenchymal, 8 subarachnoid, 4 intraventricular and 2 extradural hemorrhages. In 96 of the studies there was complete concurrence between the iPad and desktop interpretations for both radiologists. Of 49 hemorrhages, 48 were accurately detected on the iPad by one of the radiologists. In the remaining case, a tiny intraventricular hemorrhage was missed by both radiologists on the iPad as well as on the workstation, indicating that the miss was more likely related to the very small size of the hemorrhage than the viewer used. CONCLUSION: We conclude that in the emergency setting, a mobile device with appropriate web-based pictue archiving and communication system (PACS) is effective in the detection of intracranial hemorrhage present on head CT.