Comparison of 3D Double Inversion Recovery (DIR) versus 3D Fluid Attenuated Inversion Recovery (FLAIR) in precise diagnosis of acute optic neuritis.

BACKGROUND: The small size, intraorbital fat, perioptic CSF sheath and air-bone interface pose challenges to optic nerve imaging in cases of acute optic neuritis. The study is intended to compare the diagnostic accuracy of 3-dimensional Fluid Attenuation Inversion Recovery (3D FLAIR) and 3-dimensional Double Inversion Recovery (3D DIR) in cases of acute optic neuritis (AON). METHODS: Cases of AON with visual evoked potentials (VEP) abnormality were recruited and compared with controls. Imaging protocol incorporated 3D FLAIR and 3D DIR to routine sequences. The optic nerve signal was evaluated for hyperintensity across three segments viz, intraorbital, prechiasmatic, and optic-chiasm segments. The inter-modality agreement, odds ratio, receiver operator characteristics (ROC) curve, Signal intensity ratio (SIR) and interobserver agreement (between two experienced neuroradiologists) was compared between the sequences. RESULTS: Good Intermodality agreement (IMA) was found in the PC segment (ICC: 0.748, p < 0.001) in the Likert scale. In a binary scale of analysis (signal Normal vs abnormal) Kappa was highest for the PC segment (0.525, p < 0.001). The 3D-DIR sequence had an overall higher odds ratio (OR) of detecting abnormality compared to 3D-FLAIR. OR was highest for 3D DIR in the Orbital segment (OR: 3.64, P-value < 0.001) and for FLAIR in the chiasmal segment (OR 2.25, P = 0.007) for predicting optic neuritis. The area under the ROC curve for 3-D DIR was larger across all the segments (0.8 vs 0.623, p < 0.001). The Area under ROC for signal intensity ratio was higher for 3D-DIR(0.844 vs 0.704, p = 0.004) CONCLUSION: 3D DIR, under its unique contrast-generating scheme, demonstrates a greater diagnostic accuracy and offers confidence in the diagnosis of AON lesions when compared to 3D FLAIR.

MRI Spectrum of Toxic Encephalopathy-An Institutional Experience.

Background: There are numerous toxins that affect our nervous system, both central and peripheral. Innumerable differentials exist in patients of acute encephalopathy and the list can be narrowed down with appropriate imaging. Specific neuroradiological features point to a particular diagnosis in a substantial number of cases. Objective: Through this study, we aimed to demonstrate the varied imaging findings of toxic encephalopathy on MRI encountered at our institute. Material and Methods: A retrospective analysis of the patients clinically diagnosed as toxic encephalopathy and referred for imaging between March 2015 and December 2019 was done. A total of 25 patients were included. Patient records were reviewed for clinical details, laboratory investigations, and treatment; the institute Picture Archiving and Communication System provided the imaging findings. Results: Patients presenting were aged between 22 and 55 years (mean-34.3 years). Four patients (16%) presented with imaging findings characteristic of Marchiafava-Bignami disease and six patients (24%) had MRI findings of Wernicke encephalopathy. Three patients (12%) had methanol poisoning sequelae while imaging findings of nitroimidazole drug toxicity were observed in another three patients (12%). Two patients (8%) each of carbon monoxide poisoning and lead toxicity were seen. We had one patient (4%) each of isoniazid, methyl iodide, dextropropoxyphene toxicity, chronic toluene abuse, and hyperglycemia-induced hemiballismus-hemichorea. Conclusion: Our study illustrates the amalgamated spectrum of MRI appearances in various subgroups of toxic encephalopathies. Imaging substantiated by relevant history and clinical manifestations can accurately diagnose the possible causative agent in the majority of the cases.

Multiparametric magnetic resonance imaging features of giant intracranial tuberculomas.

OBJECTIVES: To evaluate Magnetic Resonance Imaging (MRI) features of Giant Tuberculomas (GT) of the brain and deduce characteristic imaging phenotypes which may differentiate GT from higher grade glioma. METHODS: A retrospective analysis of MRI was done on Tuberculomas of size >2 cm. The diagnosis was established by histopathology or presumed from size reduction on follow-up MRI while on empirical anti-tubercular therapy (ATT). Multimodality characteristics of GT on T1/T2W, Fluid attenuation recovery (FLAIR), Diffusion-Weighted imaging (DWI), Susceptibility Weighted Imaging (SWI), Spectroscopy (MRS) and Perfusion weighted sequences were assessed. These imaging features were also evaluated in WHO Grade IV, IDH-wild type glioma (histopathologically and genetically proven) and a comparative analysis of the imaging features between GT and glioma was done. RESULTS: Thirty-two GT and 20 glioma were evaluated. Pronounced intralesional T2 hypointensity (n = 8;25%), T2 hyperintense crescent beneath the periphery (n = 25, 78.1%), T2W lamellated/whorled appearance (n = 17;53.125%), hyperintense rim on T1W MT (n = 25;78.1%), peripheral rim of diffusion restriction (n = 22; 68.75%), peripheral rim of blooming on SWI (n = 20, 62.5%), prominent lipid resonance on MR spectroscopy (n = 30; 93.75%), overshoot of the signal intensity-time curve above the base line (n = 9/10; 90%) on dynamic susceptibility contrast (DSC) perfusion, were remarkable imaging characteristics. Reduction of peripheral T1 hyperintensity, compaction of T2 hypointense core, expansion of sub-marginal T2 hyperintense rim and increased peripheral susceptibility (n = 20; 62.5%) during follow-up imaging, while on ATT, were standout features. GT could be differentiated from WHO grade IV (IDH-wild type) glioma on the basis of a significantly higher proportion of GTs showing a whorled/lamellated appearance, T1 hyperintense rim, T2 hypointense core, DWI-ADC mismatch, well-defined rim on SWI, prominent lipid peak on MRS and a submarginal T2 hyperintense rim. GT showed a higher normalized ADC ratio from the core as well as the rim. Significantly higher proportion of glioma showed a T1 hypointense and T2 hyperintense core and a nodular rim enhancement. A significantly higher r CBV, Choline to creatine, choline to NAA ratio and mean thickness of the peripheral enhancing rim were defining features among gliomas. CONCLUSION: Neuroimaging features of GT have been elucidated. Reduction of peripheral T1 hyperintensity, compaction of T2 hypointense core, expansion of sub-marginal T2 hyperintense rim, and increased peripheral susceptibility on follow-up may be considered imaging markers of response to anti-tubercular therapy. Multiparametric MRI features can differentiate GT from WHO grade IV (IDH-wild type) glioma.

Isolated thrombosis of cortical veins - Clinical and radiological correlation.

Isolated cortical venous thrombosis (ICVT) is a relatively rare clinical entity with non-specific clinical presentations. Anatomical variations in cortical veins and the lack of a gold standard imaging feature make the diagnosis of ICVT challenging. Headache and seizures were the most common presentations. The Vein of Trolard followed by superficial middle cerebral vein (SMCV) were the most commonly involved. Susceptibility Weighted Imaging (SWI) cord sign was observed in 100% of the cases. CT cord sign and filling defects on contrast enhanced CT were evident in 46.7% and 10% of the cases, respectively. Notably, in the absence of filling defect visualized on contrast CT, MRI, replacement of flow void was the surrogate marker for the ICVT. A high index of clinical suspicion, a thorough understanding of neurovascular anatomy, multiparametric, multiplanar MRI protocol is required to diagnose this rare entity. A serpiginous blooming structure within the subarachnoid space identifiable in less than two contiguous sections on SWI in the vicinity of haemorrhagic infarction should alert the clinician to the imaging possibility of ICVT.

Endovascular management of dissecting posterior cerebral artery aneurysm associated with persistent hypoglossal artery: A case report.

Persistent embryological connections between the anterior and posterior circulations are rare entities. Persistent hypoglossal artery is the second most common persistent carotid-basilar anastomosis. As it is often associated with hypoplasia of vertebral arteries, it poses a challenge during endovascular interventions. We present a case of a 32-year-old woman who presented with occipital headache of four weeks' duration. Magnetic Resonance Angiography showed hypoplastic vertebral arteries with a persistent hypoglossal artery arising from the cervical segment of the left internal carotid artery and supplying the entire posterior circulation, associated with a dissecting aneurysm of the right posterior cerebral artery. Endovascular parent vessel occlusion was performed for the dissecting posterior cerebral artery aneurysm by navigating the guide catheter, microwire, and microcatheter through the persistent hypoglossal artery because the vertebral arteries were hypoplastic. Post-intervention, the patient did not develop any neurological deficit and was discharged in a stable condition.

Conexões embriológicas persistentes entre as circulações anterior e posterior são entidades raras. A artéria hipoglossa persistente é a segunda anastomose carotídeo-basilar persistente mais comum. Como está frequentemente associada à hipoplasia das artérias vertebrais, apresenta um desafio durante as intervenções endovasculares. Apresentamos o caso de uma mulher de 32 anos que apresentou cefaleia occipital com duração de quatro semanas. A angiografia por ressonância magnética mostrou artérias vertebrais hipoplásicas com artéria hipoglossa persistente surgindo do segmento cervical da artéria carótida interna esquerda e suprindo toda a circulação posterior com um aneurisma dissecante da artéria cerebral posterior direita. A oclusão endovascular do vaso parental foi realizada para o aneurisma da dissecção da artéria cerebral posterior pela passagem de cateter guia, microfio e microcateter pela artéria hipoglossa persistente, pois as artérias vertebrais eram hipoplásicas. Após a intervenção, a paciente não apresentou déficit neurológico e recebeu alta em uma condição estável.

"Neuroimaging in ethambutol induced optic neuropathy: MRI in time can save the vision".

Ethambutol is an integral part of Antitubercular therapy (ATT) and is often associated with optic neuropathy, However, neuroimaging of ethambutol induced optic neuropathy has been sparsely reported in the literature. We describe the case of a 45-year male patient, diagnosed as Tuberculous spondylodiscitis and was on ATT. Four months after ATT initiation, he presented with visual blurring in both the eyes with bitemporal hemianopia and central scotomas. Visual evoked potential (VEP) revealed prolonged latencies in N75 and P100 waveforms bilaterally. Magnetic Resonance Imaging (MRI) showed optic chiasma and bilateral optic tract hyperintensities on 3D Fluid Attenuated Inversion Recovery (FLAIR) and 3D Double Inversion Recovery (DIR) sequences. Ethambutol was discontinued immediately. On follow-up after 8 weeks, visual acuity reversed back to normal in both eyes.

Endovascular management of dissecting posterior cerebral artery aneurysm associated with persistent hypoglossal artery: A case report / Tratamento endovascular do aneurisma dissecante da artéria cerebral posterior associado à artéria hipoglossa persistente: relato de caso

Abstract Persistent embryological connections between the anterior and posterior circulations are rare entities. Persistent hypoglossal artery is the second most common persistent carotid-basilar anastomosis. As it is often associated with hypoplasia of vertebral arteries, it poses a challenge during endovascular interventions. We present a case of a 32-year-old woman who presented with occipital headache of four weeks' duration. Magnetic Resonance Angiography showed hypoplastic vertebral arteries with a persistent hypoglossal artery arising from the cervical segment of the left internal carotid artery and supplying the entire posterior circulation, associated with a dissecting aneurysm of the right posterior cerebral artery. Endovascular parent vessel occlusion was performed for the dissecting posterior cerebral artery aneurysm by navigating the guide catheter, microwire, and microcatheter through the persistent hypoglossal artery because the vertebral arteries were hypoplastic. Post-intervention, the patient did not develop any neurological deficit and was discharged in a stable condition.

Resumo Conexões embriológicas persistentes entre as circulações anterior e posterior são entidades raras. A artéria hipoglossa persistente é a segunda anastomose carotídeo-basilar persistente mais comum. Como está frequentemente associada à hipoplasia das artérias vertebrais, apresenta um desafio durante as intervenções endovasculares. Apresentamos o caso de uma mulher de 32 anos que apresentou cefaleia occipital com duração de quatro semanas. A angiografia por ressonância magnética mostrou artérias vertebrais hipoplásicas com artéria hipoglossa persistente surgindo do segmento cervical da artéria carótida interna esquerda e suprindo toda a circulação posterior com um aneurisma dissecante da artéria cerebral posterior direita. A oclusão endovascular do vaso parental foi realizada para o aneurisma da dissecção da artéria cerebral posterior pela passagem de cateter guia, microfio e microcateter pela artéria hipoglossa persistente, pois as artérias vertebrais eram hipoplásicas. Após a intervenção, a paciente não apresentou déficit neurológico e recebeu alta em uma condição estável.

Ruptured vertebrobasilar junction aneurysm unmasking subclavian steal syndrome.

BACKGROUND: Subclavian steal occurs due to stenosis or occlusion of the subclavian artery or innominate artery proximal to the origin of the vertebral artery. Often asymptomatic, the condition may be unmasked due to symptoms of vertebrobasilar insufficiency triggered by strenuous physical exercise involving the affected upper limb. The association of vertebrobasilar junction (VBJ) aneurysms with subclavian steal syndrome has been rarely reported. Hereby, we present a case of VBJ aneurysm associated with subclavian steal treated successfully with endovascular coiling. CASE DESCRIPTION: A 65-year-old female presented in the emergency department with acute severe headache and vomiting with no focal neurological deficits. Non-contrast computed tomography of the brain showed modified Fischer Grade 3 subarachnoid hemorrhage. Subsequent digital subtraction angiogram (DSA) showed VBJ aneurysm directed inferiorly with the left subclavian artery occlusion. There was retrograde filling of the left vertebral artery on right vertebral injection, confirming the diagnosis of subclavian steal. Balloon assisted coiling of the VBJ aneurysm was performed while gaining access through the stenotic left vertebral artery ostium which provided a more favorable hemodynamic stability to the coil mass. CONCLUSION: Subclavian steal exerting undue hemodynamic stress on vertebrobasilar circulation can be an etiological factor for the development of the flow-related aneurysms. Access to the VBJ aneurysms may be feasible through the stenosed vertebral artery if angioplasty is performed before the coiling of the aneurysm.

Endovascular Management of Traumatic Vertebral Artery Pseudoaneurysm Associated with Vertebral Arteriovenous Fistula Using a Covered Stent.

Vertebral arteriovenous fistula is an abnormal communication between the vertebral artery and adjacent venous structures. The most common cause of vertebral arteriovenous fistula is trauma, however, spontaneous occurrence is also known. We report a case of traumatic pseudoaneurysm with associated vertebral arteriovenous fistula which occurred following stab injury to the left vertebral artery. The diagnosis was suspected clinically and on CT angiography. Digital subtraction angiography confirmed the diagnosis, and a covered stent was placed in the left vertebral artery at the site of the injury following which there was complete closure of the pseudoaneurysm and fistula and anterograde flow was restored in the vertebral artery.

Pulmonary mycotic pseudo-aneurysm with a prior history of ventricular septal defect. Case report with review of literature.

In general aneurysms of the pulmonary arteries are less frequent than intracranial, aortic or other vascular locations. Infectious causes include bacteria such as Staphylococcus sp and Streptococcus sp, mycobacteria, Treponema pallidium (syphilis) and rarely fungi. We report a 7 year old female with two right-sided parahilar pseudo-aneurysm of fungal origin with a prior history of ventricular septal defect. Pulmonary mycotic pseudo-aneurysms are very rare and require a high suspicion to diagnose. If a patient is still symptomatic for fever and cough for a long time, and consolidation on x-ray is not improving on antibiotics, contrast-enhanced computed tomography is indicated. It can be suspected that the "friable mass attached to ventricular septal defect patch" was a source of fungeal emboli to pulmonary arteries thus giving weight to the infective endocarditis etiology. A prior history of ventricular septal defect repair could favour fungal endocarditis.

Rhinosporidiosis: A Rare Cause of Proptosis and an Imaging Dilemma for Sinonasal Masses.

Background. Rhinosporidiosis is a common disease entity in tropical countries; however, it can be encountered in other parts of the world as well due to increasing medical tourism. It may mimic other more malignant and vigorous pathologies of the involved part. Case Report. We present a case of a 36-year-old male presenting with proptosis due to involvement of nasolacrimal duct which is rare. We will discuss typical CT and MRI features of the disease which were present in the case. Conclusion. For a surgeon and a radiologist, this is a necessary differential to be kept in mind for sinonasal masses. CT and MRI are invaluable investigations. However, FNAC is confirmatory. Both clinical and radiological aspects are required to reach correct diagnosis.