8th Baltic Congress of Radiology

Nuclear Medicine

poster abstract

Crossed cerebellar diaschisis (CCD) is a reduction in glucose metabolism and decrease in blood flow in the cerebellum secondary to a supratentorial lesion in the contralateral cerebral hemisphere, most likely caused by the interruption of the white matter tracts (although the exact mechanism is unknown). The most common cerebral lesion is infarction, but there is a whole plethora of lesions that produce the same findings - e.g. tumors, intracerebral hemorrhage, encephalitis etc. CCD can be seen in computed tomography (CT) and magnetic resonance imaging (MRI) perfusion studies as a decrease in blood flow and volume and in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) as marked hypometabolism of the affected cerebral hemisphere and contralateral cerebellar hemisphere.

In this case report we present an incidental finding of CCD on 18F-FDG PET/CT in a patient with septic endocarditis.

A 90-year-old man was admitted to Tartu University Hospital with gradually worsening frailty and subfebrile temperatures that had lasted for a week, the night before admission he had fallen down the stairs. He was admitted to the hospital with a suspected neuroinfection. Past medical history was significant for an aortic valve bioprosthesis 4 years earlier and an iodine allergy. During admission the patient was somnolent, had left sided hemiparesis, a shallow nasolabial groove, tongue deviation to the right and a positive Babinski sign. He also had elevated inflammatory markers (C-reactive peptide was 115 mg/l). At admission a CT scan of the head was done without contrast media (due to the aforementioned iodine allergy), which did not show any intracranial hemorrhage or signs of acute stroke. During his stay at the hospital blood cultures came back positive for Enterococcus faecalis. The combination of aortic valve bioprosthesis, elevated CRP, temperatures >38 C, and E. faecalis led the cardiologists to suspect endocarditis. Transthoracic and - esophageal echocardiography were inconclusive and did not show any vegetations. 18F-FDG PET/CT scan was ordered with the indication of infection of unknown origin. The PET/CT confirmed the bioprosthesis infection, but also showed a marked reduction in glucose metabolism in the right cerebral hemisphere and contralateral, left cerebellar hemisphere - Crossed Cerebellar Diaschisis - suggesting a right supratentorial lesion. Considering the past medical history the patient probably had an infarction of the right hemisphere due to septic emboli caused by infective endocarditis. An MRI study confirmed the findings of early subacute ischemic stroke in the middle cerebral artery territory. The patient received appropriate antibiotic treatment for endocarditis, which showed to be effective, but developed Clostridium difficile enterocolitis as a complication and, unfortunately, died a few weeks later.

Crossed cerebellar diaschisis (CCD) is a reduction in glucose metabolism and decrease in blood flow in the cerebellum secondary to a supratentorial lesion in the contralateral cerebral hemisphere, most likely caused by the interruption of the white matter tracts. The most common cerebral lesion is infarction. In this case report we present an incidental finding of CCD on 18F-FDG PET/CT in a patient with septic endocarditis.

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