Rasmussen's Encephalitis MRI Findings

Rasmussen encephalitis is a chronic, progressive inflammation of the brain of un-known origin. The onset is in childhood and is characterized by an abrupt appearance of focal, persistent motor seizure activity (epilepsia partialis continua), followed by hemiplegia and progressive cognitive deterioration. Early diagnosis and treatment with immunoactive agents or hemispherectomy are sought to prevent the cognitive decline. A hypothesis of the pathogenesis is glutamate receptor autoimmunity associated with persistent viral infection. This receptor activation may trigger seizures in these patients.



CT and MRI Images of All patients display cortical atrophy associated with ipsilateral ventricular enlargement and caudate atrophy, more severe in those with hemiparesis. The most affected areas were insular, temporal and parietal regions. Gray and white matter focal signal intensity abnormalities (hyperintense signal in long TR-weighted images) were found in with hemiparesis.

Histopathologic examination of biopsy material reveals a characteristic triad of findings: perivascular lymphocytic cuffing of round cells, gliosis and microglial nodules. CT and MRI demonstrate progressive destruction of a single cerebral hemisphere. Decreased NAA and elevation of glutamate/glutamine levels on MRS are reported.



MRS performed showed increased lactate and choline and decreased NAA in atrophic regions in a patient with Rasmussen's Encephalitis.

18 FDG PET/CT Role In Inflammatory Conditions

Early diagnosis or exclusion of infection and inflammation is critical for the optimal management of patients with such common disorders. Currently, the integration of molecular imaging using PET with other structural imaging modalities including CT and MRI provides a unique tool combining both functional data with precise anatomic details of the body. Greatest utility of PET imaging has been reported in osteomyelitis, complicated lower-limb prostheses, complicated diabetic foot, arthritis, fever of unknown origin, acquired immunodeficiency syndrome, inflammatory bowel disease, lung and pleural diseases, atherosclerosis, vasculitis, clots, vascular graft infection and fistula. Fused molecular and structural imaging has been recognized and increasingly employed for detecting, characterizing, and monitoring patients with suspected and proven infections, and inflammatory disorders of known and unknown etiologies.

Does MRI Solve Liver Problems?

MR imaging is considered the most accurate modality to the image the liver for the detection and characterization of focal and diffuse liver diseases.The superiority of MR imaging compared with other imaging modalities for liver evaluation has become more even apparent because of substantial improvements in 1.5 T magnets with faster image acquisition and better quality. Advancements in MR imaging hardware ,software and contrast agents have made a major impact on imaging of the liver, phased array surface coil technology significantly improved SNR and conventional spin echo pulse sequences have been replaced by faster sequences .Gradients-echo (GRE) sequences generally are used for T1–weighted sequences and echo-train sequences are used for T2–weighted sequences. Introduction of parallel imaging techniques has enabled further reduction of acquisition time and improved spatial resolution.

Radiology

Radiology is a medical specialty that employs the use of imaging to both diagnose and treat disease visualized within the human body. Radiologists use an array of imaging technologies such as x-ray radiography, ultrasound, computed tomography (CT), nuclear medicine, positron emission tomography (PET) and magnetic resonance imaging (MRI) to diagnose or treat diseases. Interventional radiology is the performance of (usually minimally invasive medical procedures with the guidance of imaging technologies. The acquisition of medical imaging is usually carried out by the radiographer or radiologic technologist.