There is a need for increased use of dual imaging modalities in patients presenting with clinical features suspicious for CS. However, in this case the initial CMR was completely normal. That raises the concern for the quality or sensitivity of the current MRI imaging sequences in detecting early cardiac changes, especially localized inflammation that is small enough to be missed in conventional CMR protocols. In a recent study, patients with a new-onset atrioventricular block, 8 % were positive for cardiac sarcoidosis only on CMR compared to 33 % were positive only on FDG PET scan (9). The discrepancy in identification more cardiac involvement in CMR group, could be explained partially by the variability in the size and location of focal inflammation.
Therefore, in select cases such as patients with complete heart block, especially in the absence of extra-cardiac involvement, we propose obtaining thin sequences of the inter-atrial septum and AV nodal region to enhance the ability of CMR to detect small early lesions in the conduction system.