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374 Cardiac MRI vs PET Scan

Perfusion-metabolism mismatch using N-13 ammonia & F-18-FDG PET imaging tracer
suggesting decreased perfusion with adequate metabolism in the involving intero- septal
and apical. Myocardium in the lower row images as compared to match defect involving
anterior segment seen in the upper images.

Clinical uses of cardiac MRI Vs PET scan in
infiltrative cardiac disease :

Cardiac MRI Vs PET scan in sarcoidosis ,
Amyloidosis :

The high spatial resolution and soft tissue character-
ization of cardiac MRI imaging has shown a great po-
tential in the identification & evaluation of myocardial
alteration related to inflammatory cardiomyopathies
such as sarcoidosis . Sarcoidosis is a granulomatous
disease of unknown etiology that most commonly
affects the lungs and mediastinal lymphnodes with
cardiac involvement responsible for 30% to 85% of
deaths from an atrio -ventricular conduction block
Resting myocardial perfusion image shows multiple defects in antero-septal and apical or ventricular arrhythmia related to granulomatous in
myocardial segment(Ist row of images.) without any evidence of hibernating myocardium
in the form of match defects on FDG images(2nd row) filtration or subsequent fibrotic scars. The diagnosis
of cardiac sarcoidosis is often confirmed invasively
by endomyocardial biopsy performed through right
heart catheterization. Since cardiac involvement is
homogeneous, the histologic confirmatory diagnos-
tic & procedural risk are related to the number & lo-
cation of samples and there is a high prevalence of
negative findings. An accurate noninvasive imaging
technique is therefore necessary to exclude cardiac
involvement or to help guide biopsy in segments
with suspected infiltration. Cardiac MR imaging has
emerged as the current modality of choice for the
diagnosis of cardiac involvement; with regional func-
tional assessments T weighted sequences for the
2
detection of oedema & inflammation complementing
the LGE sequences for the identification of fibrotic
tissue. The value of F-18 FDG PET studies for identify-
ing cardiac sarcoidosis & correlative studies of CMR &
PET showed comparable accuracy of both modalities
Resting myocardial perfusion image shows multiple perfusion defects seen in anteri- in detecting myocardial lesion with better correlation
or,septal and apical myocardial segments (1 st row of images),which shows significant of abnormal PET findings. But preparation before PET
evidence of hibernating myocardium involving anterior and apical myocardial segments
in the form of mismatch defects without any evidence of hibernating myocardium in study is very much crucial to have optimal images
septal segment in the form of match defect(scarred myocardium
such as extended fasting, a low protein, high fat diet
or heparin infusion. However simultaneous PET / MR
imaging in patients with suspected cardiac sarcoid-
osis benefits from the improved spatial resolution
of LGE sequences to describe areas of myocardial
infiltration that can be further characterized by their
metabolic activity on PET images as inflammatory
or scar related, complimenting the less specific MR
sequences. Additionally PET also provides a more
comprehensive whole body assessment of extra car-
diac involvement including pulmonary or neurologic
extension of the disease that are less accessible by
MR imaging alone.

GCDC 2017