NUCLEAR MEDICINE OF HEART AND LUNG

Slides of lectures + electronic books:

http://www.nmc.dote.hu/

László Galuska

ÁOK TOK 2011

1

Clinical decision tree in CAD

Abnormal pump

function

Stress-restMPI

Normal

perfusion

Normal

Activeischemia

Stress: defectRest: better or normal

Glucose

metab?

Fixed defect

CoronarographyRevascularization

Viable

hybernated

Present

ScarNo

Nothing

to do

Nothing

to do

The role of risc factors!

2

Single photon isotop labelled

Radiopharmaceuticals for MPI (comparison)

• Thallium-chloride:– K-analogue– Redistribution may occur

– A single injection during stress• Early images after 15’• Late images after 3-4 h

• Metoxy-Iso-Butil-Isonitril (MIBI):

– Passes cells membranes passively (negative membrane potential). Accumulates in the mitrocondrias

– No redistribution– Separate injections for stress and rest study (images after 60’)– Single-day protocol:

• Starting with rest preferred• ~250 + 750 MBq

3

PET Radiopharmaceuticals

Summ. of myocard metabolism

Summary of myocardial substrate metabolism and PET tracers. FTHA 14(R,S)-[18F]fluoro-6-thia-heptadecanoic acid, FOP 15-[18F]fluoro-3-oxapentadecanoate

2

(Takashi Kudo nyomán) 4

Imaging in nuclear medicine.

Gamma camera (up)

Cardio - SPECT (down)SPECT-CT (up)

PET-CT (down5

RADIONUCLIDE STUDIES OF THE HEART

• Ventricular wall motion• Myocardial perfusion

• Myocardial glucose metabolism

• Hybrid technics (PET/CT, SPECT/CT

• 123I-MIBG

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Equilibrium ECG-gated ventriculography

Pharmaceutical: [Tc-99m] in vivo labelled red blood cells(with pyrophosphate)

Phenomenonimaged:

Changing blood content of the ventriclesand atria during the cardiac cycle

Acquisitionmode

ECG-gated, averaging some hundreds ofcycles.

Quantitativeparameters:

• Left (and right) ventricular ejectionfraction

• Peak filling and emptying rate• Left ventricular volume

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ECG gating

8

Normal

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ECG-gated RN ventriculography: apical aneurism

10

Myocardial perfusion scintigraphy

Pharmaceuticals: [Tl-201] Thallium-chloride or[Tc-99m] isonitrile derivatives (e.g. "MIBI")

Phenomenonimaged:

Myocardial perfusion after ergometric orpharmaceutical stress and in resting state.

Abnormalitiesshown:

• "Fix defect" (decreased activity in both thestress and rest images) in scars.

• Reversible perfusion defect in ischeamicregions:Relatively decreased activity uptake (ascompared to the healthy myocardium) inthe regions of stenosed coronary arteries,not or less shown in rest (Tl: delayed)images.

11

Myocardial perfusion scintigraphy:Indications - 1

• Suspicion of CAD with abnormal rest or indeterminate stress ECG

• Localization and severity of ischaemia

• Interpreting the (abnormal) result of coronarography(collaterals, microvasculature); assessing haemodynamic effects of the stenosis

• Result of surgical or catheteric intervention

• Prognosis of CAD

1212

Myocardial perfusion scintigraphy:Indications - 2

• Assessing the location and severity of ischaemia in case of post-infarct angina for angioplasty

• Assessing myocardial viability in severe left ventricular insufficiency after infarct

• Cardiac risk stratification before major (chest, abdominal) surgery

Imaging techniques:

I. planar

II. tomograhic (SPECT; PET)

1313

Planar

projectionsand coronary

vessel territories

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Redistribtion by TlCl

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Coronary artery territories on SPECT views

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A. RCAB. Aortic archC. Pulmonary arteryD. LCAE. LCXF. LAD

SHORT AXIS SLICES

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Polar map

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Reverzible defect:

short axis slices

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Reverzible defect:vertical long axis slices

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Reverzible defect:

horizontal long axis slices

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Reverzible defect: bull’s eye

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Fix defect: horizontal long axis slices

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Fix defect: bull’s eye

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Viable: short axis sl.

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Viable: bull’s eye

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DISA: Perf and metabolic mismach: short ax.

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DISA: Perf+metab. fix defect: non viable scar

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Hybrid technics: The parameters of 64 slice CT are suitable for noninvasiv

investigation of structure of coronary arteries.

In one hybrid system are the CT (structure) and metabolic (functional) informations !

The main question: where is ischemia ? The perfusion stress /rest Images and their

fusion answer it.

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Hybrid technics: 64 (or more) slice CTA and MPI with image fusion

a, b Semiquantitative polar maps of perfusion during vasodilator stress (a) and at rest (b), showing

a reversible perfusion defect at the lateral base (arrowheads). For presentation purposes, functional (MPI)

and morphological (CTA) information was fused, generating three-dimensional (3D) volume-rendered

SPECT/CT images. c Anterior view of fused 3D SPECT-CT images showing serial lesions of the prominent

first diagonal branch (arrows) which are not haemodynamically relevant. d The lateral view shows a

subtotal or total occlusion of the mid LCX (arrows) and the corresponding ischaemia (arrowheads)

matching the territory of the LCX

30

13-N-NH3 stress

18-F-FDG viability

13-N-NH3 rest oblique slices

Images courtesy of Dr. A. Alavi, Univ. of Pennsylvania Hospital, Philadelphia

� flow & viability at same

high sensitivity at same day

� partial match

� as blood supply vanishes

myocardium dies

� dynamic/gated possible

PET in cardiology: NH3 PET blod flow & FDG viability

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Images courtesy of Dr. Blaufox, Montefiore Hospital, New York

1850 MBq 82Rb, 4 min. p.i.

total acq. time: 4.5 min.including em. + transm.

� very short half life

(72 s) tracer w. long

positron travel range

� generator isotope

� still good image

quality w/o artifacts

from high activity

in liver

PET in cardiology: 82 Rb PET blod flow

32

Dynamics of norepinephrine and 123J-MIBG.

a Norepinephrine (NE) is stored in synaptic vesicles at sympathetic nerve endings and is released via exocytosis due to nerve excitement. Most of the released NE returns to the nerve ending via the re-absorption mechanismdesignated as uptake-1. A fraction of the released NE becomes bound to the receptors, while the remaining part is released into the blood by spillover. The NE is ultimately inactivated by COMT and MAO.

b MIBG is also incorporated into nerve endings via uptake-1, and released via the excitement of nerves, in a manner similar to NE. MIBG, however, is neither bound to the receptors nor degraded byenzymes. Owing to these characteristics, most of the MIBG is reabsorbed via uptake-1, and retained in the nerve ending for many hours

3333

Method of calculating the H/M ratio and washout rate on 123J-MIBG planar images

34

Evaluation of risk areas in acute coronary syndrome

One case of unstable angina in which MIBG was of diagnostic value. Female, aged 62 years. The patient was admitted to the hospital owing to a diagnosis of unstable angina, but no significant findings were obtained on 201TlCl myocardial perfusion SPECT at rest. MIBG showed decreased accumulation in the infero-posterior wall. On the delayed image, increased washout was observed at the same site, and the abnormal findings became more marked. On coronary angiography performed later, advanced stenosis was recognised in the proximal part of the right coronary artery.

3535

Usefulness of 123J-MIBG in HCM

Prediction of the therapeutic effects of β-blockers by MIBG myocardial scintigraphy (quoted from [59]). In 53 patients with dilated cardiomyopathy who received β-blocker therapy continuously for 6 months or longer, MIBG myocardial scintigraphy was performed twice, before and 6–12 months after the start of the treatment. The improvement in the washout rate after treatment was the strongest predictor of prognosis. No cardiac events occurred in the group of patients showing an improvement in washout rate by 10% or more following β-blocker therapy. Table 1 shows the relationship of various clinical characteristics to washout rate improvement by β-blocker therapy. Lower values of the extent score and higher values of the washout rate on the early image were predictive of washout rate improvement by β-blocker therapy and were thus also predictive of a favourable long-term prognosis. 36

36

The nuclear medicine of lung

Principles of

Lung structure

Combined lung investigations (perfusion-ventillation)

Tc99m-aeroszol

Kr-81m

Xe-133

Tc-99m-MAA: 20um

Normal Matching perf./vetill. defect

primary airway

obstruction

secondary

vasospasm

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Combined lung investigations

Tc99m-aeroszol

Kr-81m

Xe-133

Tc-99m-MAA: mean 20um

Normal Perf./inhal. mismach

bronchokonstrikció

válasz a hypoxiára

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Radiopharmaceuticals

99mTc T1/2: 6 h

generátor-termék

140 keV gammasugárzás

makroaggregats----perfusion

microsphaers-------perfusion

aerosols--------------ventillation

foszfonats---------- bone scan

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Radiopharmaceuticals for ventillation studies

• Solubil:(DTPA, MDP)

• Non solubil:(HSA, Technegas,vvt.)

• Kr-81m gas

Nebulisers:• Pressed air:

(MEDI61, Venticis)• Ultrasonography:

(Solcovent)• Alkoholic solution with

vacuum:(APE)

• Noble gas

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Clinical indications:

•Pulmonary embolisation: Combined perf. and ventill.

Study, 6 directions

•Before lung operation: to measure the ventill. capacity

•Developmental disorders of lung: perf and ventill

Art. Pulm agen.

•Demage of alveolocapillary junction: alveolitis

dynamic ventillation scintigraphy

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The causes of perfusional abnormalities

• pulmonary embolisation(trombus, sepsys, fat, air )

• tumor/or hylar adenopathia• vasculitis• a. pulm. atresia seu

hypoplasia• Fibrotisating mediastinitis

• AVM• a. pulmonary

sarcoma• intravenous drug• TBC• External radiation

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Normal 99mTc-MAA perfusion and 81mKr ventillation study

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Matching perfusion and ventill. defect

45

Art. Pulm. agenesia

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Normal DTPA clearance

Faster DTPA clearance (smoking!)

Dinamic inhalation scintigrphy

47

99m-Tc DTPA clearance is faster:

• smoking ( reversibil) • alveolitis• Sarcoidosis

• pneumonitis• Flame inhalation (fireman!)• interstitial pneumonia• lung manifestations of Immunological illneses

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