Multi-Res-Attention UNet: A CNN Model for the Segmentation of Focal Cortical Dysplasia Lesions from Magnetic Resonance Images.

In this work, we have focused on the segmentation of Focal Cortical Dysplasia (FCD) regions from MRI images. FCD is a congenital malformation of brain development that is considered as the most common causative of intractable epilepsy in adults and children. To our knowledge, the latest work concerning the automatic segmentation of FCD was proposed using a fully convolutional neural network (FCN) model based on UNet. While there is no doubt that the model outperformed conventional image processing techniques by a considerable margin, it suffers from several pitfalls. First, it does not account for the large semantic gap of feature maps passed from the encoder to the decoder layer through the long skip connections. Second, it fails to leverage the salient features that represent complex FCD lesions and suppress most of the irrelevant features in the input sample. We propose Multi-Res-Attention UNet; a novel hybrid skip connection-based FCN architecture that addresses these drawbacks. Moreover, we have trained it from scratch for the detection of FCD from 3 T MRI 3D FLAIR images and conducted 5-fold cross-validation to evaluate the model. FCD detection rate (Recall) of 92% was achieved for patient wise analysis.

Ectopic Cervical Thymus in an Infant with Normal Orthotopic Thymus: Role of Imaging in Diagnosis and Management.

Ectopic cervical thymus (ECT) is a rare cause of solid cervical mass in the pediatric age group. The location of the mass along the path of thymic descent (thymopharyngeal duct), sonographic echo pattern and MR signal intensity identical to that of normal orthotopic thymus in the anterior mediastinum help us in making a confident diagnosis. To the best of our knowledge only nine cases have been reported in infants in the literature. We present a case of ECT presenting as a right upper neck mass in a 2 month old child.

Haemosiderin cap sign in cervical intramedullary schwannoma mimicking ependymoma: how to differentiate?

A 37-year-old female presented with gradually progressive asymmetric ascending paraesthesia and weakness involving bilateral upper and lower limbs. The MRI spine images revealed expansile intramedullary, solid cystic, peripherally enhancing lesion with a haemosiderin cap along the lower margin. The lesion extended into the left C5 and C6 nerve root exit zones, along with thickening and enhancement of the nerve roots. She underwent excision of the lesion, which revealed intramedullary schwannoma on histopathological examination. Presence of the cap, an extension of the lesion into the nerve root exit zone, with associated thickening and enhancement of the dorsal nerve roots should alert the radiologist to consider the possibility of intramedullary schwannoma rather than ependymoma. Schwannoma showing compact Antoni A area with Schwannian whorls and nuclear palisades (A,B) and loose Antoni B area with haemosiderin pigment (C). The tumour exhibits diffuse positivity for S-100 protein (D) and negativity for GFAP (E). [Stain: A-C: Haematoxylin and Eosin; D,E: Immunoperoxidase. Magnification = Scale Bar, A-E: 100µm].

Bipartite craniopharyngeal canal with a lipoma and cephalocele: a previously unreported entity.

A 13-year-old male child was evaluated for headache and visual deterioration; he underwent routine MRI imaging which revealed a large craniopharyngeal canal, divided by an abnormal bony septum giving a bipartite appearance of the canal, with a lipoma and cephalocele on either side of the septum. The child had undergone a previous surgery for cleft palate repair at the age of 7. The child had normal pituitary function inspite of nonvisualization of pituitary gland in MRI. To best our knowledge, this is the first case with such a variation. We have also discussed the possible embryological hypothesis for this previously unreported entity. Knowledge about this rare variant might have surgical relevance in selected cases.

Is Acoustic Radiation Force Impulse (ARFI) Ultrasound Elastography Valuable in the Assessment of Cervical Lymphadenopathy?

Cervical lymphadenopathy frequently poses a diagnostic challenge as neither clinical nor imaging assessment can reliably differentiate between benign and malignant lymphadenopathy. Non-invasive differentiation between the two may help to reduce the number of FNAC or biopsy. The purpose of this study was to evaluate whether the new ARFI technique (Virtual Touch Quantification), in conjunction with gray scale sonography and Doppler, can help in the characterization and differentiation of benign from malignant cervical lymphadenopathy. Fifty adult patients with cervical lymphadenopathy were included in the study and sonoelastography was done. Sonoelastographic findings were compared to the gold standard histopathology or cytopathology. ARFI measurements in benign and malignant enlarged lymph nodes were compared using the Student t test and ROC curve was used to arrive at the Youden index, sensitivity, specificity, PPV, NPV and diagnostic accuracy. Sonographic patterns indicative of malignancy includes heterogenous echopattern, short axis/long axis ratio > 0.5, absent echogenic fatty hilum and mixed vascular pattern. Sensitivity, specificity, PPV, NPV and accuracy in differentiation between the benign and malignant lymph nodes using ARFI elastography was 79.17, 100, 100, 83.9 and 89.9% respectively. ROC curve analysis of SWVs for differentiation between the malignant and benign lymph nodes gave a cut-off value of 2.8 m/s with an area under curve of 0.892. ARFI imaging technique quantifies the tissue stiffness of the cervical lymph nodes non-invasively and aids in characterisation and differentiation of benign from malignant cervical lymphadenopathy in conjunction with conventional sonography.

Cerebral Vasculopathy in Coarctation of Aorta-a Rare Association.

Coarctation of aorta is a rare congenital cardiovascular condition where patients are at risk of systemic arteriopathy, including hypertension and intracranial aneurysms.1 Here we report a rare case of young ischemic stroke, who was found to be having a cerebral vasculopathy and coarctation of aorta on evaluation.