The hippocampus is a small but complex anatomical structure that plays an important role in spatial and episodic memory. The hippocampus can be affected by a wide range of congenital variants and degenerative, inflammatory, vascular, tumoral and toxic-metabolic pathologies. Magnetic resonance imaging is the preferred imaging technique for evaluating the hippocampus. The main indications requiring tailored imaging sequences of the hippocampus are medically refractory epilepsy and dementia. The purpose of this pictorial review is threefold: (1) to review the normal anatomy of the hippocampus on MRI; (2) to discuss the optimal imaging strategy for the evaluation of the hippocampus; and (3) to present a pictorial overview of the most common anatomic variants and pathologic conditions affecting the hippocampus.Teaching points
• Knowledge of normal hippocampal anatomy helps recognize anatomic variants and hippocampal pathology.
• Refractory epilepsy and dementia are the main indications requiring dedicated hippocampal imaging.
• Pathologic conditions centered in and around the hippocampus often have similar imaging features.
• Clinical information is often necessary to come to a correct diagnosis or an apt differential.
There are no density thresholds for PCHDs that allow predicting the absence or presence of hemorrhage with 100% specificity and acceptable sensitivity. A CT scan performed at least 19-24 h after endovascular therapy is the only reliable method to differentiate contrast staining from hemorrhage.
A recently-described assay for xanthine oxidase was used for the estimation of serum xanthine oxidase (SXO) in patients with a variety of liver disorders. SXO was markedly increased in acute viral hepatitis, and in some patients with chronic aggressive hepatitis. In other forms of chronic liver disease or obstructive jaundice, there was little or no increase of this enzyme in serum. The results of a study of experimental liver damage in rats suggest that SXO is more sensitive than serum aminotransferases in detecting acute liver damage.
Subtotal resection of the head of the pancreas combined with duct obliteration of the distal pancreas by prolamine was performed in 12 selected patients who had chronic alcohol-induced pancreatitis with most destruction in the proximal pancreas. The main indication for operation was intractable pain. There was no postoperative mortality but morbidity was high when no pancreaticojejunostomy was constructed. After a follow-up period of 32 months, lasting pain relief was obtained in 10 patients; pseudocyst formation occurred in three patients; calcification of the distal pancreas, absent before operation, was demonstrated in four of six patients; six of 11 nondiabetic patients became hyperglycemic either abruptly (1 patient) or progressively (5 patients); quality of life improved in most patients. This procedure preserves the stomach, duodenum, spleen, distal pancreas and common bile duct if possible. However, pancreatic ductal obliteration with prolamine does not prevent relapses of chronic pancreatitis.
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