Post on 03-Jan-2016
description
Dr Hussein Farghaly
PSMMC
Radionuclide Brain Imaging
Master Watermark Image: http://williamcalvin.com/BrainForAllSeasons/img/bonoboLH-humanLH-viaTWD.gif
Lecture 6
Amyloid PET imaging
• New tracer for PET• Carbon-11 (C-11)-labeled Pittsburgh• compound B (PiB), Ab—or amyloid PET• [F-18]florbetapir, achieved approval by the U.S. Food and Drug Administration in April 2012
• Targets amyloid beta senile plaques and neurofibrillary tangles
• Long retention times in hippocampus
Parkinsonism
• results from the deterioration of neurons in the region of the brain called the substantia nigra. These neurons normally produce the neurotransmitter dopamine, which sends signals to the basal ganglia, a mass of nerve fibres that helps to initiate and control patterns of movement.
Tyrosine
L-DOPA
DA
Vesicles
D2 Receptors
Pre-synaptic terminal
Post-synaptic cell
MAO-B
COMT
Glial cell
Dopamine Transporters
Dopamine synthesis
Targets for dopaminergic ligands
Tyrosine
L-DOPA
DA
VesiclesPre-synaptic terminal
Post-synaptic cell
MAO-B
COMT
Glial cell
Targets for dopaminergic ligands
F18-Dopa
I123 FPCIT or ß-CIT
I123 IBZM or epidepride ***
Normal Dopamine Transporter (DATSCAN) images
MRI
DATSCANSPECT
Head of Caudate
Putamen
Body of Caudate
A PD image with DaTSCAN
Medial part of SN projects to caudateLateral part of SN projects to putamen
In PD the lateral part of SN always degenerates first
preferential loss in putamenrelative to caudate
Diagnosis and staging of Parkinson’s Disease
Normal PD: 1 PD: 2 PD: 3
Objective measurement of progression in assessment of therapy
Even on first presentation SPECT shows loss of 50% of
neurones
Clinical diagnosis
Imaging diagnosis
CISTERNOGRAPHY
CSF CIRCULATION• CSF flows from lateral ventricles through interventricular foramina (of Monro), into third ventricle, through cerebral aqueduct (of Sylvius), into fourth ventricle, through median aperture (foramen of Magendie) and lateral apertures (foramina of Luschka) into cisterna magna. CSF enters subarachnoid space, circulating around brain and spinal cord before being absorbed in arachnoid granulations over cerebral hemispheres
CISTERNOGRAPHY
HydrocephalusHydrocephalus is abnormal enlargement of the CSF spaces resulting from abnormalities of CSF production, circulation, or absorption (Table 13-4). MRI and CT are most often used to select patients who might benefit from intervention, whereas radionuclide cisternography is generally reserved for situations that remain unclear
Cisternography: Protocol Summary
Normal cisternogram. Anterior and lateral images 4 and 24 hours after intrathecal radiotracer injection show normal transit up over the convexities with no ventricular reflux.
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Communicating normal pressure hydrocephalus at 24 hours (top row), 48 hours (middle row) and 72 hours (bottom row) in anterior (left), right lateral (middle) and left lateral (right) projections. Ventricular reflux (closed arrowhead) is present,as is very delayed flow over the convexities (open arrowhead). The intracerebral activity at 72 hours was caused by transependymal uptake.
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Surgical Shunt Patency
A variety of diversionary CSF shunts (ventriculoperitoneal, ventriculoatrial, ventriculopleural, lumboperitoneal) have been used to treat obstructive hydrocephalus.
Complications may include catheter blockage, infection, thromboembolism, subdural or epidural hematomas, disconnection of catheters, CSF pseudocyst, bowel obstruction, and bowel perforation.
The diagnosis of shunt patency and adequacy of CSF flow can often be made by examination of the patient and inspection of the subcutaneous CSF reservoir. Whenthis assessment is uncertain, radionuclide studies with In-111 DTPA or Tc-99m DTPA are useful for confirming the diagnosis.
Shunt Patency: Protocol Summary
Cerebrospinal shunt patency evaluation. A,Ventriculoperitoneal shunt at 10 min(left) shows activity in the reservoir port and distal limb of the shunt moving down the neck and chest. Intraventricular activity is also seen. By 30 minutes (middle), activity is in the abdomen with free flow in the peritoneum (right).
Ventriculopleural shunt with normal radiotracer flow through the shunt into the pleural space which decreases over time.
Obstructed cerebrospinal shunt. After injection of Tc-99m DTPA into the reservoir, good reflux into the ventricles is seen, consistent with patency of the proximal limb of the shunt.However, no distal drainage occurs over 60 minutes from obstruction.
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Common sites of cerebrospinal fluid leakage
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Cerebrospinal Fluid Leak
Placement of pledgets for cerebrospinal fluid leak study. The labeled cotton pledgets are placed by an otolaryngologist at various levels within the anterior and posterior nares to detect leakage from the frontal, ethmoidal, and sphenoidal sinuses.
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• Positive radionuclide CSF leak study. In-111 DTPA left lateral views show increasing radioactivity over time originating from the nares and leaking into the nose and mouth (arrowheads).
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