Incidentally detected right aortic arch with mirror image branching in a patient with rheumatic calcific mitral valve disease.

An isolated right-sided aortic arch with no congenital heart disease is extremely rare. We report an adult woman with longstanding rheumatic heart disease causing severe calcific mitral stenosis, moderate mitral regurgitation and moderate pulmonary hypertension, for which she underwent mitral valve replacement and tricuspid annuloplasty. On preoperative work-up, she was detected to have a right-sided aortic arch with mirror image branching along with a ductal dimple. However, there were no associated congenital cardiac defects.

Dwell Time of Stentriever Influences Complete Revascularization and First-Pass TICI 3 Revascularization in Acute Large Vessel Occlusive Stroke.

OBJECTIVE: In acute ischemic stroke with large vessel occlusion, the interaction between the clot retriever and the stent is critical for achieving successful recanalization. The ideal time of stent deployment (dwell time [DT]) to improve revascularization is currently unknown. We systematically analyzed the effect of different DT on final angiographic and clinical outcomes of patients who underwent mechanical thrombectomy. METHODS: The DT was progressively increased from 3 minutes to 5 minutes and then 8 minutes during the study period. The effect of DT on recanalization attempts, successful angiographic outcome (thrombolysis in cerebral ischemia [TICI] 2b or TICI 3), total revascularization time, and immediate and 3-month clinical outcomes were evaluated. The DT of 3 minutes and 5 minutes (DT3-5) was compared against DT of 8 minutes (DT8). RESULTS: Forty patients were included in the analysis. Good angiographic outcome was observed in 94.1% of patients in the DT8 cohort with an average attempt of 1.2 compared with 78.3% with average attempts of 2.0 in other group. Single-pass good recanalization (TICI 2b or 3) and single-pass complete revascularization (TICI3) was significantly higher in the DT group compared with the DT3-5 group (82.4% vs. 43.5% [P = 0.013] and 42.9% vs. 8.7% [P = 0.003], respectively). A favorable trend toward a reduced overall procedural time (34.59 vs. 55.59 minutes) was observed, but was not statistically significant (P = 0.15). CONCLUSIONS: Mild prolongation of DT to 8 minutes improves revascularization outcome with fewer attempts, possibly because of better clot-stent interaction.

The application of susceptibility-weighted MRI in pre-interventional evaluation of intracranial dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: Detection and characterization of intracranial dural arteriovenous fistula (DAVF) is important to plan appropriate therapeutic management. The aim of this study was to analyze the utility of susceptibility-weighted MRI (SWI) in the pre-therapeutic assessment of DAVF in comparison with gold standard digital subtraction angiography (DSA). MATERIALS AND METHODS: Prospectively, 26 patients with DAVFs underwent a thorough clinical examination and MRI including SWI followed by cerebral DSA. Two observers blinded to the DSA findings evaluated conventional MRI and SWI images and identified the fistulous area (FA), cortical venous reflux (CVR), and cortical venous ectasia (CVE) and compared these observations with the DSA findings documented by a third observer. RESULTS: Aggressive clinical symptoms were observed in 31% of patients and benign features were noted in 69% of DAVFs. Conventional MRI could identify the FA in only 27% of patients. SWI accurately located 75% of all the FAs in 23 patients. However, SWI failed to identify DAVFs in three patients. CVR was detected in 89.6% of all aggressive DAVFs. The accuracy of SWI to identify CVE was 100% and the extent and degree correlated with DSA observations. CONCLUSIONS: SWI is a reliable non-invasive tool for the localization and characterization of DAVFs and is superior to conventional MRI in the evaluation of DAVFs. This sequence can demonstrate underlying cerebral hemodynamic stresses with a high degree of accuracy and provide valuable pre-therapeutic information.

The making of indigenous vascular prosthesis.

BACKGROUND & OBJECTIVES: Vascular illnesses are on the rise in India, due to increase in lifestyle diseases and demographic transition, requiring intervention to save life, organ or limbs using vascular prosthesis. The aim of this study was to develop indigenous large diameter vascular graft for treatment of patients with vascular pathologies. METHODS: The South India Textile Research Association, at Coimbatore, Tamil Nadu, India, developed seamless woven polyester (Polyethylene terephthalate) graft at its research wing. Further characterization and testing followed by clinical trials were conducted at Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. Fifteen in vivo experiments were carried out in 1992-1994 in pigs as animal model. Controlled (phase I) clinical trial in ten patients was performed along with control graft. Thereafter, phase II trial involved 22 patients who underwent multi-centre clinical trial in four centres across India. RESULTS: Laboratory testing showed that polyester graft was non-toxic, non-leeching and non-haemolytic with preserved long-term quality, further confirming in pigs by implanting in thoracic aorta, comparable to control Dacron grafts. Perigraft incorporation and smooth neointima formation which are prime features of excellent healing characteristics, were noted at explantation at planned intervals. Subsequently in the phase I and II clinical trials, all patients had excellent recovery without mortality or device-related adverse events. Patients receiving the test graft were followed up for 10 and 5 years, respectively. Serial clinical, duplex scans and CT angiograms performed periodically confirmed excellent graft performance. INTERPRETATION & CONCLUSIONS: Indigenously developed Chitra vascular graft was comparable to commercially available Dacron graft, ready for clinical use at affordable cost to patients as against costly imported grafts.

Rosette forming glioneuronal tumor of the fourth ventricle in squash cytology smear.

Rosette forming glioneuronal tumor (RGNT) is a recently recognized and extremely rare glioneuronal tumor occurring in the fourth ventricle. It is crucial for the cytopathologist to be aware of this entity as it can be easily mistaken for more common neoplasms occurring at this site. We present here the cytology of such a rare case of RGNT that was misdiagnosed as ependymoma. The varying cytological features of this entity, as well as the common diagnostic difficulties encountered in cytology, are highlighted in this report.

Neuroenteric cysts of the brain-comprehensive magnetic resonance imaging.

Neuroenteric cysts are developmental cysts that should be differentiated from other, more common non-neoplastic cysts as well as cystic neoplasms. While these lesions may have varied imaging findings, T1 hyperintense prepontine lesion due to mucinous/proteinaceous content is characteristic. Location and imaging characteristics aid in formulating the correct diagnosis of neuroepithelial/neuroenteric cysts. Magnetic resonance spectroscopy (MRS) has the specific finding of N-Acetyl Aspartate (NAA)-like peak at 2.02 ppm which is not seen in other cystic lesions. In this study, we aim to discuss the imaging findings of these lesions on conventional and advanced MRI findings and provide radiologic-pathologic correlation. We also briefly describe the pathogenesis, embryology and radiological differential diagnoses of these cysts.

Multimodality imaging of carotid atherosclerotic plaque: Going beyond stenosis.

Apart from the degree of stenosis, the morphology of carotid atherosclerotic plaques and presence of neovascularization are important factors that may help to evaluate the risk and 'vulnerability' of plaques and may also influence the choice of treatment. In this article, we aim to describe the techniques and imaging findings on CTA, high resolution MRI and contrast enhanced ultrasound in the evaluation of carotid atherosclerotic plaques. We also discuss a few representative cases from our institute with the related clinical implications.

Spontaneous intracranial hypo and hypertensions: an imaging review.

Cerebrospinal fluid (CSF) pressure changes can manifest as either intracranial hypertension or hypotension. The idiopathic forms are largely under or misdiagnosed. Spontaneous intracranial hypotension occurs due to reduced CSF pressure usually as a result of a spontaneous dural tear. Idiopathic intracranial hypertension (IIH) is a syndrome of elevated intracranial tension without hydrocephalus or mass lesions and with normal CSF composition. Neuroimaging plays an important role in excluding secondary causes of raised intracranial tension. As the clinical presentation is varied, imaging may also help the clinician in arriving at the diagnosis of IIH with the help of a few specific signs. In this review, we attempt to compile the salient magnetic resonance imaging findings in these two conditions. Careful observation of these findings may help in early accurate diagnosis and to provide appropriate early treatment.

Applications of 3D CISS sequence for problem solving in neuroimaging.

Three-dimensional (3D) constructive interference in steady state (CISS) is a gradient-echo MRI sequence that is used to investigate a wide range of pathologies when routine MRI sequences do not provide the desired anatomic information. The increased sensitivity of the 3D CISS sequence is an outcome of the accentuation of the T2 values between cerebrospinal fluid (CSF) and pathological structures. Apart from its well-recognized applications in the evaluation of the cranial nerves, CSF rhinorrhea and aqueduct stenosis, we have found the CISS sequence to be useful for the cisternal spaces, cavernous sinuses and the ventricular system, where it is useful for detecting subtle CSF-intensity lesions that may be missed on routine spin-echo sequences. This information helps in the management of these conditions. After a brief overview of the physics behind this sequence, we illustrate its clinical applications with representative cases and discuss its potential role in imaging protocols.

Susceptibility-weighted imaging in differentiating bilateral medial thalamic venous and arterial infarcts.

Bilateral medial thalamic infarcts may be due to thrombosis of internal cerebral veins or occlusion of artery of Percheron. Conventional MR imaging is often not helpful in differentiating the two. We discuss two cases in whom susceptibility-weighted imaging, including phase images contributed in demonstrating the thrombosed or patent internal cerebral veins.

Clinical utility of susceptibility-weighted imaging in vascular diseases of the brain.

Susceptibility-weighted imaging (SWI) is a rapidly evolving technique that utilizes both the magnitude and phase information to obtain valuable information about susceptibility changes between tissues. SWI is very sensitive to the paramagnetic effects of deoxyhemoglobin. SWI plays an important role in the diagnostic evaluation and management of acute stroke. In addition, it also plays an important role in the imaging of patients with chronic arterial occlusion and in understanding the effects of chronic infarction, like incomplete infarction and cortical laminar necrosis. The hemodynamic status and oxygen extraction fraction can also be evaluated. SWI is useful in evaluating cerebral venous sinus thrombosis by demonstrating the hemorrhagic venous infarction and thrombus in the sinus and the cortical veins, as well as secondary phenomena like venous stasis in the form of engorged cortical and transmedullary veins and collateral slow flow. Low-flow vascular malformations that are not visualized well on conventional sequences are depicted in exquisite detail along with the venous components on SWI. SWI is used for evaluating cavernomas, developmental venous anomalies, telangiactasias, dural arteriovenous fistulas and the various components of arteriovenous malformations. It has also evolved as a noninvasive technique for evaluating various anomalies of the venous system without administering contrast. Vasculopathies and vasculitis are associated with cerebral microbleeds which are detected on SWI. On the basis of the additional information provided by SWI, it can be included in the routine brain imaging protocol.