Whole brain atlas-based diffusion kurtosis imaging parameters for evaluation of minimal hepatic encephalopathy.

BACKGROUND AND PURPOSES: Minimal hepatic encephalopathy (MHE) has no recognizable clinical symptoms, but patients have cognitive and psychomotor deficits. Hyperammonemia along with neuroinflammation lead to microstructural changes in cerebral parenchyma. Changes at conventional imaging are detected usually at the overt clinical stage, but microstructural alterations by advanced magnetic resonance imaging techniques can be detected at an early stage. MATERIALS AND METHODS: Whole brain diffusion kurtosis imaging (DKI) data acquired at 3T was analyzed to investigate microstructural parenchymal changes in 15 patients with MHE and compared with 15 age- and sex-matched controls. DKI parametric maps, namely kurtosis fractional anisotropy (kFA), mean kurtosis (MK), axial kurtosis (AK) and radial kurtosis (RK), were evaluated at 64 white matter (WM) and gray matter (GM) regions of interest (ROIs) in the whole brain and correlated with the psychometric hepatic encephalopathy score (PHES). RESULTS: The MHE group showed a decrease in kFA and AK across the whole brain, whereas MK and RK decreased in WM ROIs but increased in several cortical and deep GM ROIs. These alterations were consistent with brain regions involved in cognitive function. Significant moderate to strong correlations (-0.52 to -0.66; 0.56) between RK, MK and kFA kurtosis metrics and PHES were observed. CONCLUSION: DKI parameters show extensive microstructural brain abnormalities in MHE with minor correlation between the severity of tissue damage and psychometric scores.

Post-Tracheostomy Vascular Injury to the Anomalous Thymic Branch Managed by Endovascular Coiling.

BACKGROUND: Tracheostomy-related arterial haemorrhage can be devastating especially if arising from an obscure anomalous vessel which can potentially complicate treatment decision. METHODS: We report a case of non-Hodgkin's lymphoma with upper airway obstruction, who had profuse bleeding, post-tracheostomy, from the stomal site. CT angiography showed presence of a pseudoaneurysm adjacent to the tracheostomy site which was confirmed on catheter angiography to be arising from anomalous thymic branch of right common carotid artery (CCA). Superselective cannulation of the anomalous thymic artery was done using a microcatheter with subsequent coil embolization. RESULTS: Post-coiling, the bleeding stopped immediately and the patient recovered. He was under oncology care till 3 months following embolization and was doing well. CONCLUSIONS: The emergency physicians should be aware of this rare variation of thymic artery while performing tracheostomy. Ultrasound as point-of-care device may help mitigate these complications. Endovascular embolization is a minimally invasive and effective management option for an injured arterial branch from a tracheostomy.

Unusual Cause of Encephalopathy and Seizures in a Child.

Toxic encephalopathy is an important differential diagnosis in a child with encephalopathy and seizures. Subtle circumstantial evidence and apt neuroimaging features can significantly contribute to management, especially in a case of accidental exposure. 2, 4-D (ethyl ester) poisoning is a rare diagnosis, despite the common usage of this toxic compound as weedicide in northern India. The clinical similarity to the anticholinesterase poisoning, especially in the setting of agrochemical exposure is the main cause of under-diagnosis with usually fatal outcomes. We present an interesting case of accidental 2, 4-D (ethyl ester) poisoning in a child with typical neuroimaging features. A review of the literature regarding neuroimaging patterns of bilaterally symmetrical signal abnormalities involving basal ganglia in brain magnetic resonance imaging (MRI) from the point of view of clinical significance, is also discussed.

Pattern Recognition Approach to Brain MRI Findings in Patients with Dengue Fever with Neurological Complications.

BACKGROUND AND PURPOSE: Dengue can present with variable neurological complications including encephalitis, encephalopathy, acute disseminated encephalomyelitis (ADEM), and ischemic and hemorrhagic stroke. Our study describes a pattern-based approach to recognize different brain MRI findings in dengue-seropositive patients with neurological symptoms. MATERIALS AND METHODS: Thirty-six serologically proven dengue patients with neurological symptoms and undergoing brain MRI over a 6-month period were included in this study. The diagnosis of dengue encephalopathy or encephalitis was established by presence of signs/symptoms of acute encephalitic syndrome with the presence of Immunoglobin M (IgM) antibody against dengue antibody in the serum and/or presence of dengue antigen (NS1) in serum. The MRI brain along with diffusion weighted imaging and susceptibility weighted imaging sequences were evaluated by an experienced neuroradiologist. RESULTS: Eleven patients had normal MRI finding. In the rest 25 patients, 12 were found to have encephalitic pattern, 4 had encephalopathic (seizure related/metabolic) pattern, 3 had features of ADEM, and isolated micro- or macro-hemorrhages were found in 6 patients. In the encephalitis group, eight had concomitant involvement of brainstem, cerebellum, and ganglio-thalamic complexes with additional involvement of cortex and subcortical white matter (WM) found in three. Isolated brainstem and cerebellar involvement were seen in three in this group, whereas one had isolated cerebellar involvement. Interspersed hemorrhage was noted in the structures involved in eight patients in encephalitis group. CONCLUSION: Radiologists should be aware of various MRI brain findings in dengue and a pattern recognition approach often helps in reaching the correct diagnosis albeit after exclusion of other differentials based on laboratory studies.

Tandem occlusion involving accessory middle cerebral artery in acute ischaemic stroke: management strategies.

Occlusion of both the limbs of accessory middle cerebral artery (AMCA) poses a unique challenge in management of acute ischaemic stroke by mechanical thrombectomy. The patient is a 30-year-old man, presenting with acute onset of left-sided hemiparesis for 4 hours. Non-contrast CT brain showed no bleed and three-dimensional CT angiogram of head and neck vessels showed dissection involving right carotid bulb and tandem occlusion of right MCA with presence of two MCA stumps. Aspiration thrombectomy was done using a reperfusion catheter, advanced separately into both the MCA stumps and complete recanalisation of both the limbs of MCAs was achieved, which was found to be AMCA. Balloon angioplasty for the internal carotid artery dissection was performed. Although occlusion of AMCA in acute ischaemic stroke is a chance occurrence, it is important to identify this variant as recanalisation of both the limbs by mechanical thrombectomy is required for favourable outcome after the procedure.

Intracranial Germinoma Masquerading as Secondary Granulomatous Hypophysitis: A Case Report and Review of Literature.

Germinomas are highly immunogenic tumors eliciting a strong peri-tumoral immune response that can spillover into the surrounding healthy tissues. This phenomenon can also occur in intracranial germinomas, manifesting as secondary hypophysitis. Herein, we report a case of 12-year-old-girl presenting with polyuria and polydispsia. She had central diabetes insipidus (CDI) and panhypopituitarism. Imaging revealed a sellar-suprasellar mass with infundibular stalk thickening. Transphenoidal biopsy revealed epithelioid granulomas with immunostaining negative for germinomatous cells. Other causes of hypophysitis were ruled out. Accordingly, she was diagnosed as primary granulomatous hypophysitis and treated with high-dose corticosteroids. Three years later she again presented with headache, vomiting and diminution of vision. Imaging showed a heterogeneous, solid-cystic peripheral rim-enhancing lesion at the same location with involvement of hypothalamus, ependyma and pineal gland. Cerebrospinal fluid beta-human chorionic gonadotropin was markedly elevated, confirming the diagnosis of an intracranial germ cell tumor. She was started on chemotherapy; however, she succumbed to febrile neutropenia. We performed a literature search and found 18 anecdotal cases of secondary hypophysitis associated with intracranial germinomas. There was a slight male preponderance (male:female 5:4). Two-thirds of the cases were below 18 years of age. Polyuria was the most common presenting manifestation (83%). CDI and panhypopituitarism were seen in 89 and 78% cases, respectively. Imaging evidence of pituitary stalk thickening was seen in 12 cases (67%), while pituitary enlargement and/or sellar mass were reported in 11 cases (61%). Pineal involvement was extremely rare, being reported in only 1 case, implying the predilection of suprasellar (rather than pineal) germinomas in causing secondary hypophysitis. Histologically, 82% had lymphocytic hypophysitis, while 18% had granulomatous hypophysitis. Initially, the diagnosis of germinoma was missed in 60% of the cases who were wrongly treated with corticosteroids. To conclude, physicians should make it a dictum that all children and adolescents presenting with CDI and pituitary stalk thickening should be rigorously screened for an underlying intracranial germinoma before labeling them as primary hypophysitis.

Synchondral Fracture of the Posterior "Hemiarch" of Pediatric Atlas with Cerebrospinal Fluid Fistula following a Penetrating Neck Injury.

INTRODUCTION: As such, the incidence of spinal fractures in young children is less than that of adults due to an increased pliability of the immature bones. The presence of unfused synchondroses in these children predisposes them to an infrequent pattern of fractures that traverse through ossification centers. Such synchondral injuries are uncommonly reported in the C1 and C2 vertebrae. Those that have been occasionally described in C1 involved the anterior synchondrosis. Furthermore, penetrating injuries to a pediatric spine are relatively rare. CASE PRESENTATION: In this context, we present a 4-year-old child in whom a penetrating injury to an immature atlas led to an unusual disjunction of the posterior synchondrosis with fracture displacement of the posterior "hemiarch" of the atlas that plunged into the dura, resulting in a cerebrospinal fluid fistula. CONCLUSION: We discuss the possible mechanism and considerations in the management of this unique presentation. Such an atypical fracture pattern involving the posterior hemi ring of the pediatric atlas is previously unknown.

Anomalous V3 Segment Aneurysm Associated with Congenital Atlantoaxial Dislocation: Case Report and Discussing the Challenges in Management.

BACKGROUND: An anomalous vertebral artery is not a deterrent for posterior C1-C2 joint manipulation and reduction of atlantoaxial dislocation (AAD). However, presence of an incidental aneurysm in the aberrant segment of artery with concurrent AAD adds to the surgical challenge. CASE DESCRIPTION: A 30-year-old woman presented with neck pain and spastic quadriparesis. Her imaging revealed atlantoaxial dislocation and bony segmentation defects. Three-dimensional computed tomography angiography showed bilateral anomalous vertebral arteries (V3 segment) and an incidental aneurysm on the arterial segment that crossed the right C1-C2 joint posteriorly. Because the artery bearing the aneurysm was nondominant, it was ligated and successful C1-C2 posterior reduction and fusion could be performed. CONCLUSION: The association of an incidental aneurysm with an anomalous vertebral artery in congenital AAD is unusual. The etiology could be an underlying collagen defect or repeated shearing trauma to the vessel wall due to C1-C2 instability. It would be less risky to proceed with endovascular embolization followed by occipitocervical fusion without opening the joints in case the aneurysm is present on the dominant aberrant V3 segment. Ventral decompression can be supplemented for irreducible AAD. On the contrary, if the aneurysm is present on the nondominant aberrant V3 segment, the C1-2 joint can be opened and manipulated following an initial endovascular treatment of the aneurysm. If the circumstances demand, the nondominant artery can be ligated and sacrificed, although there is a small risk of formation of stump aneurysm.