At inversion time (TI) = 80 ms, all structures are below the null point and appear gray on the image. At TI = 120 ms, a large portion of the subendocardial left ventricular (LV) myocardium (white arrows) goes through the null point earlier than the LV cavity, which crosses the null point at a TI of 200 ms (white circle). Because this region (subendocardial circumference and right ventricle) is obviously not a coronary artery distribution territory, this area is highly likely to represent myocardial disease such as cardiac amyloid (high signal at 240 ms). The myocardium surrounding this region is likely to be normal, as it is nulled at a TI of 240 ms (white arrows in black framed image). CMRI = cardiovascular magnetic resonance imaging.

(Top row) Contrast short-axis CMRI of Patient #17 (basal slice on the left with subsequent 6-mm slices toward the apex shown to the right; there is a 4-mm gap between slices; TI = 220 ms). For contrast CMRI analysis, each short-axis image was divided into 12 circumferential segments by applying a grid, as demonstrated in the upper row. (Bottom row) Histopathological workup of endomyocardial biopsy (EMB) samples for cardiac amyloidosis included Masson’s trichrome staining with amyloid deposits (arrows) between myocytes (A), Congo red staining (B) with demonstration of typical red/green birefringence (*) under cross-polarized light (C), as well as electron microscopy visualizing amyloid deposits between myocytes expanding the extracellular volume (D and E). LGE = late gadolinium enhancement; other abbreviations as in Figure 1.

In both patients, LGE was diffusely distributed in large areas of the left ventricle involving the entire subendocardium (TI = 230 ms in both patients). Interestingly, the subepicardial myocardium is affected only in areas of transmural LGE. Note that LGE is also located in the papillary muscles (white arrowheads). Histologic images include Mason’s trichrome with amyloid deposits between myocytes (black arrows, large right panels) and Congo red staining (inset right panels) demonstrating typical green birefringence under cross-polarized light. Abbreviations as in Figures 1 and 2.

One patient demonstrated focal intramural LGE at the right ventricular insertion points, which is a typical finding in hypertrophic cardiomyopathy (top row, white arrows, TI = 320 ms). This diagnosis was confirmed by histopathology demonstrating myocyte hypertrophy (red cells) and interstitial fibrosis as shown by Masson’s trichrome staining (blue areas between myocytes, black arrows). Note that LGE is also present in the inferior papillary muscle in this patient (thin white arrow). The second patient was diagnosed with myocarditis exhibiting enhanced numbers of interstitial CD68+ macrophages as well as interstitial edema. Molecular pathology revealed PVB19 in the myocardium. The white arrows in the bottom panel point to typical subepicardial LGE in the left ventricular inferolateral wall (TI = 300 ms). Note that the pattern of LGE found in these patients is completely different from the LGE pattern that is usually present in patients with biopsy proven cardiac amyloidosis (Fig. 3). Abbreviations as in Figures 1 and 2.

Spatial distribution of the mean values for segmental extent of LGE values are represented as gray-scale maps in basal, mid-, and apical short-axis slices in all patients diagnosed with cardiac amyloidosis by endomyocardial biopsy (top row) and all other patients (bottom row). In patients with biopsy-proven cardiac amyloidosis, LGE is typically distributed diffusely in large areas of the left ventricle, mainly involving the subendocardial area circumferentially, whereas the subepicardial myocardium is less affected. Abbreviations as in Figure 2.

Long-axis contrast CMRI (Left) patient #2 (TI = 230 ms). (Right) necropsy sample of a different patient diagnosed with cardiac amyloidosis. Interestingly, the pattern of diffuse LGE originating from the subendocardium nicely matches the pattern of pale subendocardial amyloid deposits indicated by white arrowheads in the necropsy sample. Right panel adapted with permission from (23). Abbreviations as in Figures 1 and 2.