Nuclear imaging in cardiac patient about rest and stress thallium

1. Nuclear imaging
Dr vasanthi
Dnb ctvs
Madras medical Mission

2. SPECT (single photon emission
computed tomography)
• Radioactive material used :
• Myocardial perfusion study : Th 201,Te99m
• Radionuclide ventriculography : I 123 MIBG
Dual isotope
• Thalium for resting image
• Technitium for stress images
Principle :
• i.v – radiactive material injected
• Accumulated in myocardial cells
• Radioactive material decayed after short period of time
• Emitted photons are captured by gamma camera

5. Preparation
• Npo – 4 hrs
• No caffeine for 12 hrs
• Hold beta blockers ,CCB for24hrs
• Avoid insulin

6. • Stress images acquired after exercise or drugs which is compared
with images acquired during rest.
• Image display :
• Short axis
• Vertical long axis (VLA)
• Horizontal long axis (HLA)

7. septum
anterior
inferior
Lateral
ant
Base
apex
inferior
sep Lateral
apex
Base

8. Polar map

14. RWMA
End diastole End systole

16. Indications :
• Suspected false +ve or-ve TMT
• Resting ST changes
• LBBB,RBBB,LVH, digitalis,pre-excitation or pacemaker
• Women with +ve TMT and low or intermediate probability CAD
• Inability to exercise
• Prognosis of known CAD
• Detecting post PTCA or CABG ischaemia ( positive predictive value of 90%)
• Assessing myocardial viability
• Risk evaluation in non- cardiac surgery patients
• Assessment functional significance of documented coronary stenosis

17. Uses of SPECT
• As screening method to detect CAD (sensitivity-68%)
• Medical therapy vs revascularisation : mild defect + no high risk =
medical , high risk + multivessel disease ,large territory =
revascularisation
• Dipyramidol vasodilator stress-predicts future cardiac events

18. PET SCAN(positron emission tomography)
• Radioactive material emit positron which are detected by positron
camera
• Perfusion tracer – Rb82,N13 ammonia (cellular membrane integrity)
• Metabolic tracer – FDG 18 (glucose metabolism)