Presentation
Nephrotic syndrome. Known renal AL-amyloidosis. Known CAD, status post coronary stenting.
Patient Data
Heart rate: ~90 bpm, hematocrit 0.41
Image quality: good, occasional artifact
Morphology and functional analysis (endo-volume):
LV-EDVI: 56 mL/m²
LV-ESVI: 23 mL/m²
LV-SVI: 34 mL/m²
LV-EF: 59%
cardiac output: 5.2 L/min
cardiac index: 2.7 L/min/m²
LV-ED wall mass index (without papillary muscle): 58 g/m²
interventricular septum thickness: 13 mm
atrial septum thickness: ~7 mm
Findings:
Impaired diastolic filling with visually abnormal relaxation.
Mildly thickened left and right ventricular myocardium as well as thickened atrial septum and right atrial wall.
No significant cardiac valve pathology.
Pericardial effusion especially around the apex and the right ventricular free wall.
Bilateral pleural effusions (right ~15 mm, left ~20 mm).
Myocardial tissue properties:
STIR: diffuse high signal of the myocardium, especially in the septal and inferior segments indicating myocardial edema
Look-Locker: the myocardium is nulled before the blood pool and caused difficulties with the determination of the inversion time
PSIR/DIR: dark blood pool and diffuse partly subendocardial late gadolinium enhancement in a non-coronary distribution also affecting the right ventricular and atrial walls
T1 mapping native: 1175-1235 ms (z-score: 6-8)
extracellular volume (ECV): 46-52%
T2 mapping: 58-62 ms (z-score: 3-4)
*Normal reference ranges based on local data:
-
native T1: 940-1060 ms; ECV: >32%; T2: 44-56 ms
Impression:
cardiac MRI findings are consistent with cardiac amyloidosis
impaired diastolic filling indicating heart failure with a preserved ejection fraction (HFpEF)
myocardial edema in the setting of AL-amyloidosis carries an unfavorable prognosis
Exam courtesy: Kirsten Fleckstein, Jeanette Moses (radiographer)
Serum and urine immunofixation electrophoresis
Elevated free light chains (lambda type).
Renal biopsy
Microscopic appearance:
focal deposits of a PAS negative and Congo red positive material in the widened mesangium and partially on the walls of the capillaries pre-arterioles and arterioles within the cortex of the majority of glomeruli
interlobular arteries with moderately thickened fibrosing intima
tubular apparatus with focal atrophic changes surrounded by a thickened fibrosing interstitium
Immunohistochemistry:
Congo red positive material with positivity for lambda light chains and negativity for kappa light chains
negativity for IgM, IgG, C3, C1q and IgA
Diagnosis:
Moderate glomerular, vascular and interstitial amyloid deposits of the light chain type (AL). Moderate intimal fibrosis of intrarenal arteries and moderate focal tubular atrophy and interstitial fibrosis of the renal cortex.
Image quality: some artifacts, no other limitations
Functional analysis: no significant change in comparison to the previous examination
Impaired diastolic filling with visually abnormal relaxation.
Mildly thickened left and right ventricular myocardium, atrial septum and right atrial wall.
Mild pericardial effusion and small pleural effusions but less than in the previous study.
Myocardial tissue properties:
STIR: diffuse high signal of the myocardium, especially in the septal and inferior segments
Look-Locker: the myocardium is nulled before the blood pool as previous study (and as expected)
PSIR: dark blood pool and diffusely distributed subendocardial late gadolinium enhancement
T1 mapping native: 1100-1160 ms (z-score: 3-5)
extracellular volume (ECV): 40-50%
T2 mapping: 56-60 ms (z-score: 2-3)
*Normal reference ranges based on local data:
-
native T1: 940-1060 ms; ECV: >32%; T2: 44-56 ms
Impression:
known AL-amyloidosis under therapy
minimally restricted systolic function and abnormal diastolic relaxation
abnormal native T1 and T2 values as well as the extracellular volume as anticipated but with mild improvement compared to the previous study under therapy
Case Discussion
This case illustrates MR imaging features of cardiac amyloidosis in a patient with known AL amyloidosis.
Left and right ventricular hypertrophy, thickened atrial walls, abnormal blood-pool gadolinium kinetics and the non-coronary distribution of the findings support the diagnosis of cardiac amyloidosis 1-4 and speak against myocardial scar tissue or findings in the context of coronary artery disease.
The relatively mild increase in interventricular septum thickness, the still normal left ventricular mass, the extracellular volume of 46-52%, as opposed to higher values, and foremost the association with nephrotic syndrome are features that would favor AL over ATTR amyloidosis 5.
Evidence of myocardial edema, seen on T2 mapping and STIR images indicates a less favorable prognosis 6.
Immediately after the diagnosis of cardiac amyloidosis, the patient was also diagnosed with smoldering multiple myeloma after undergoing a bone marrow biopsy. He was treated accordingly with chemotherapy and immunotherapy.
A follow-up examination 8 months later shows mild improvement of the abnormal T1 and T2 values and extracellular volume under therapy.
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