Wen-Sheng Huang

F-18 FDG PET demonstrates crossed cerebellar diaschisis 20 years after stroke.

Stroke produces an area of focal damage and distant areas of reduced blood blow and metabolism termed diaschisis. Tc-99m ECD and HMPAO brain SPECT have demonstrated crossed cerebellar diaschisis (CCD) in patients with cerebral cortical infarct. SPECT findings reflect abnormal cerebral blood flow. CCD as shown on F-18 FDG PET reflects abnormal reflects glucose metabolism. We present the case of a patient with laryngeal cancer who also had a stroke in the left cerebral hemisphere involving the territory of the middle cerebral artery 20 years ago. This patient underwent PET, including the head and neck. A current brain F-18 FDG PET exhibited hypometabolism in the contralateral cerebellum (CCD) as well as hypometabolism of the primary insult in the left cerebral hemisphere. These findings reflect partial impairment or diminished glucose metabolism in the primary insult to the cerebrum and contralateral cerebellum. In addition, this patient illustrates that on PET imaging, CCD could be demonstrated 20 years after a stroke.

Intrathoracic gastric activity on cholescintigraphy results in a large hiatus hernia with duodenogastric reflux.

Abstract: When a radiopharmaceutial is seen in the intrathoracic cavity on Tc-99m iminodiacetic acid (IDA) cholescintigraphy, basically 2 abnormalities are seen: first the stomach, such as a hiatus hernia, which is abnormally located in the thoracic cavity, and duodenogastric reflux (bile) which is simultaneously seen. However, intrathoracic gastric activity seen on Tc-99m IDA hepatobiliary scintigraphy is rarely documented in a patient with hiatus hernia. This report is of an 83-year-old man with a large hiatus hernia with duodenogastric reflux who underwent hepatobiliary scintigraphy; the scans show an area of increased activity on the top of the liver due to duodenogastric reflux in a large hiatus hernia. This was confirmed by surgery: the patient successfully underwent laparoscopic paraesophageal hernia repair with Nessen fundoplication and laparoscopic cholecystectomy.

Hashimoto thyroiditis and Takayasu aortitis: visualization of the thyroid gland and ring appearance of the mediastinum on F-18-FDG PET.

A woman with Hashimoto thyroiditis, treated with levothyroxine for 4 years, complained of chest pain that radiated to the neck and had progressively worsened for 2 months. CT of the chest showed circumferential thickening of the ascending aorta and aortic arch, compatible with Takayasu arteritis. She underwent F-18 FDG PET imaging, which revealed an abnormal thyroid gland and a ring-like appearance of the mediastinum.

PET-CT Imaging for Radiotherapy: From Clinical Biologic Target Definition to Translational Research

Medical modalities for molecular imaging such as F-18 fluorodeoxyglucose positron emission tomography (FDG-PET), has become an important surrogate biomarker that reflects cellular glucose metabolism. It has been applied to the staging, re-staging, therapeutic monitoring and follow-up of patients with various tumors. Phenotypic information is being used to increase the accuracy of radiation treatment planning, by fusing CT planning images, which has resulted in better tumor control and fewer treatment related toxicities. Applications of PET-CT using biotracers other than FDG in clinical radiotherapy research and in translational research for radiotherapy are intensively investigated which may offer additional parameters in therapeutic targeting.

A Large and Distinct Gallbladder Fossa in a 60-miunte Image of Hepatobiliary Scintigraphy: Correlation with CT, ERCP, and Autopsy Findings

An image at 60 min of hepatobiliary scintigraphy in a patient with severe jaundice and post endoscopic retrograde cholangiopancreatogray (ERCP) illustrated prominent activity in the liver with a large and distinctive defect in the gallbladder fossa, no activity in the gallbladder, biliary duct and bowel. In addition, blood pool activity in the enlarged heart and renal activity of both kidneys and sign of ascites were also seen. These findings correlated with CT and ERCP radiographic findings showing common bile duct stones, gallbladder stones, and ascites. Dysfunction of the liver and heart failure also contributed to these findings. At autopsy, ascites, gallstones, evidence of cirrhosis of the liver secondary to hepatitis C infection, and cardiomegaly with severe coronary artery disease and myocardial infarction were confirmed.