Understanding Cardiac Amyloidosis: Role of Cardiac Magnetic Resonance Imaging

Transcription

1 Understanding Cardiac Amyloidosis: Role of Cardiac Magnetic Resonance Imaging Poster No.: C-1329 Congress: ECR 2013 Type: Educational Exhibit Authors: A. Kono, T. Nishii, M. Shigeru, S. Takamine, S. Fujiwara, K. Sugimura; Kobe/JP Keywords: Cardiac, MR, MR-Functional imaging, Diagnostic procedure, Imaging sequences, Education, Metabolic disorders, Education and training DOI: /ecr2013/C-1329 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 23

2 Learning objectives The purpose of this exhibit is To demonstrate the characteristics and the various findings of cardiac magnetic resonance (CMR) images in patients with cardiac amyloidosis (CA). To offer tips and state the pitfalls of CMR based on the patients with histopathologically proven CA in our institute between 2008 and Page 2 of 23

3 Background General aspects about amyloidosis Amyloidosis is a disease in which an insoluble amyloid protein fibril deposits mainly in the extracellular spaces of organs and tissues. Amyloid fibril proteins are rigid, non-branching fibrils approximately 10 nm in diameter. The fibrils bind the dye Congo red and exhibit green birefringence when viewed by polarisation microscopy. Fig. 1 To date, there are 27 known extracellular fibril proteins in humans (1). There are two classifications of amyloidosis, systemic and localized. Page 3 of 23

4 Definition of cardiac amyloidosis Amyloid deposition in the myocardium, conduction pathway, and coronary vessels is called cardiac amyloidosis. There are 4 types of systemic amyloidosis and one localized amyloidosis in CA. Fig. 2 CA has a poor prognosis, early recognition can improve the prognosis, helping to insure the administration of aggressive medical treatment. However, due to unspecific symptoms, the diagnosis of CA is difficult. Page 4 of 23

5 Fig. 3 The diagnosis of CA is established by direct endomyocardial biopsy or indirect investigation and histologic confirmation of amyloid on noncardiac tissue. Invasive abdominal fat pad aspiration: positive in 50-80% AL type. endomyocardial biopsy: gold standard. bone marrow biopsy: positive in 50% AL type. Non-Invasive Electrocardiogram; low voltage, pseudoinfarction pattern Echocardiogram; increased cardiac wall thickness, 'granular sparkling' appearance of the myocardium. However, this is not specific. 99m Tc-DPD scintigraphy; Accumulation is seen only in TTR-related CA (2). Role of CMR in Cardiac Amyloidosis (3) Page 5 of 23

6 1. Comprehensive exam Morphology Function Tissue characterization 2. Sensitive tool to detect the amyloid deposit LGE can identify cardiac involvement before morphologic abnormalities manifest LGE is associated with the worst clinical states Fig. 4: Representative images of 67-year-old female diagnosed with CA. Upper left: Cine image shows obvious myocardial thickness in the septum. Upper middle: T2weighted image shows high signal intensity in the postero-septal junction (arrow). Upper right: T2 map shows increased T2 value in the postero-septal junction (arrow). Lower left: Perfusion image shows delayed myocardial blood flow in the endomyocardium (arrow). Lower middle: Late gadolinium enhancement image shows global endomyocardial enhancement in the left ventricle (arrow) as well as the right Page 6 of 23

7 ventricle (dashed arrow). Lower right: Increased uptake in the myocardium is seen on 99mTc-pyrophosphate scintigraphy. Page 7 of 23

8 Images for this section: Fig. 4: Representative images of 67-year-old female diagnosed with CA. Upper left: Cine image shows obvious myocardial thickness in the septum. Upper middle: T2-weighted image shows high signal intensity in the postero-septal junction (arrow). Upper right: T2 map shows increased T2 value in the postero-septal junction (arrow). Lower left: Perfusion image shows delayed myocardial blood flow in the endomyocardium (arrow). Lower middle: Late gadolinium enhancement image shows global endomyocardial enhancement in the left ventricle (arrow) as well as the right ventricle (dashed arrow). Lower right: Increased uptake in the myocardium is seen on 99mTc-pyrophosphate scintigraphy. Dept of Radiology, Kobe University Hospital - Kobe/JP Page 8 of 23

9 Imaging findings OR Procedure details This educational exhibit shows A review of typical CMR findings such as cine, T2WI, T2 map, perfusion, and late gadolinium enhancement (LGE). This exhibit will especially focus on LGE. Tips and pitfalls of CMR in acquisition and interpretation. The techniques are described and illustrated. Morphological finding Concentric and symmetrical hypertrophy is frequent in CA in contrast to hypertrophic cardiomyopathy, which presents asymmetrical hypertrophy. Fig. 5 Page 9 of 23

10 Understanding morphological change helps to diagnose in CA when extra-cardiac histopathological evidence can be obtained by abdominal fat pad aspiration or duodenal biopsy. Moreover there is a relation between the wall thickness and the prevalence of heart failure (4). Functional analysis Diastolic function is decreased prior to the decrease of systolic function. Diastolic function can be assessed correctly by CMR (5). Diastolic function can be assessed by Time-volume curve of left ventricle analysis assessed by cine imaging (Fig.6) Flow analysis at mitral valve assessed by phase-contrast imaging (Fig.7) Fig. 6: Systolic function is preserved, however diastolic function is impaired in CA. Page 10 of 23

11 Fig. 7 T2-weighted imaging (T2WI) and T2 mapping T2WI can reveal the increase of the water component in the diseased myocardium. On the other hand, amyloid fibrils make T2 relaxation time shorter because of high molecular weights. Myocardial edema was reported in 10% of CA patients. Conventional T2WI on CMR has some limitations; 1) signal intensity variability caused by phased array coils, 2) high signal from slow moving ventricular chamber blood that can mimic and mask elevated T2 in the myocardium, and 3) motion artifacts. To overcome these limitations, T2 mapping is preferable. T2 relaxation time in CA was comparable with normal controls (6). This is explained by reduced proton density enhanced T2 decay due to the fixed position of amyloid protons in the beta pleated sheet proton structure spin-spin interactions between amyloid and adjacent water protons leading to dephasing Page 11 of 23

12 Fig. 8: High signal intensity is seen in the inferior wall (blue arrow) and the inferior septum (red arrow) on T2WI. However, the former is considered artifact because it is not seen on T2 mapping. The latter is also seen on T2 mapping. Perfusion imaging About one-third of CA demonstrates subendocardial abnormalities on rest perfusion imaging (6). This is presumed that these perfusion defects reflect subendocardial amyloid deposition infiltration of small-caliber coronary vessel walls by amyloid Page 12 of 23

13 Fig. 9: After rapid injection of the Gd-contrast agent, the signal intensity of the myocardium is getting higher. However, the endomyocardium is dark (red arrow) because of the subendocardial amyloid deposition or infiltration of small-caliber coronary vessel walls by amyloids. Inversion time scouting (TI scout) The kinetic of the gadolinium contrast agent of CA is known to be different from normal hearts and hearts with other cardiac diseases. The T1 relaxation time in myocardium is similar to that in blood, and the blood gadolinium clearance was faster in CA (7). As a result, inversion time (TI) of the myocardial nulling is faster than that of the blood pool in contrast to other diseases such as myocardial infarction. Page 13 of 23

14 Fig. 10: Inversion time (TI) of the myocardial nulling is faster than that of the blood pool in contrast to other diseases such as myocardial infarction. Late gadolinium enhancement (LGE) Graphic representation of LGE patterns are shown. Considerable number of CA patients shows various LGE on CMR; %. Because CA is a systemic disease, the LGE is observed in the global myocardium. On the other hand, due to the strange kinetic of the gadolinium agent described above, some CA cases don't have a myocardial abnormality, but have low signal intensity blood pools. This is an indirect indication, and a useful finding for the diagnosis of CA. Page 14 of 23

15 Fig. 11: A. No LGE B. Global subendocardial LGE C. Transmural LGE D. Pathy LGE E. Global transmural LGE; the contrast (bright myocardium and dark lumen) is inverted with A F. Suboptimal myocardial nulling with black blood pool; the blood pool is darker than usual, and the image has poor signal-to-noise ratio with a grainy appearance. G. Combination of various patterns described above; e.c. B+C+E A. No LGE (3%) B. Global subendocardial LGE (60%) C. Transmural LGE (NA) D. Pathy LGE (6%) E. Global transmural LGE (23%); the contrast (bright myocardium and dark lumen) is inverted with A F. Suboptimal myocardial nulling with black blood pool (8%); the blood pool is darker than usual, and the image has poor signal-to-noise ratio with a grainy appearance. G. Combination of various patterns described above (NA); e.c. B+C+E Page 15 of 23

16 The percentages in parentheses were reported from 35 histologic-proven CA cases (3). Fig. 12: Representative LGE image of 67-year-old female diagnosed with CA. This enhancement is a combination of global subendocardial enhancement, transmural enhancement and black blood pool. Clinical impact of CMR for the diagnosis of CA The diagnosis of CA has been depending on clinical symptoms, laboratory data, and echo. Furthermore, the definitive diagnosis has been made by endomyocardial biopsy (Fig.13). However, existing diagnostic steps will be changed by CMR, which has the potential to eliminate cardiac echos and invasive biopsies (Fig.14). Page 16 of 23

17 Fig. 13 Page 17 of 23

18 Fig. 14 Page 18 of 23

19 Images for this section: Fig. 10: Inversion time (TI) of the myocardial nulling is faster than that of the blood pool in contrast to other diseases such as myocardial infarction. Dept of Radiology, Kobe University Hospital - Kobe/JP Page 19 of 23

20 Fig. 11: A. No LGE B. Global subendocardial LGE C. Transmural LGE D. Pathy LGE E. Global transmural LGE; the contrast (bright myocardium and dark lumen) is inverted with A F. Suboptimal myocardial nulling with black blood pool; the blood pool is darker than usual, and the image has poor signal-to-noise ratio with a grainy appearance. G. Combination of various patterns described above; e.c. B+C+E Dept of Radiology, Kobe University Hospital - Kobe/JP Page 20 of 23

21 Fig. 14 Dept of Radiology, Kobe University Hospital - Kobe/JP Page 21 of 23

22 Conclusion LGE on CMR is a promising technique to diagnose CA because LGE is sensitive in detecting amyloid deposits within the myocardium. In order to analyze and interpret the various CMR image findings, radiologists must be able to precisely diagnose CA. Page 22 of 23

23 References Sipe JD, Benson MD, Buxbaum JN, Ikeda S, Merlini G, Saraiva MJ, et al. Amyloid fibril protein nomenclature: 2010 recommendations from the nomenclature committee of the International Society of Amyloidosis. Amyloid Sep;17(3-4): Gertz MA, Comenzo R, Falk RH, Fermand JP, Hazenberg BP, Hawkins PN, et al. Definition of organ involvement and treatment response in immunoglobulin light chain amyloidosis (AL): a consensus opinion from the 10th International Symposium on Amyloid and Amyloidosis, Tours, France, April Am J Hematol Aug;79(4): Syed IS, Glockner JF, Feng D, Araoz PA, Martinez MW, Edwards WD, et al. Role of cardiac magnetic resonance imaging in the detection of cardiac amyloidosis. JACC Cardiovascular imaging Feb;3(2): Klein AL, Hatle LK, Burstow DJ, Seward JB, Kyle RA, Bailey KR, et al. Doppler characterization of left ventricular diastolic function in cardiac amyloidosis. J Am Coll Cardiol Apr;13(5): Paelinck BP, Lamb HJ, Bax JJ, Van der Wall EE, de Roos A. Assessment of diastolic function by cardiovascular magnetic resonance. Am Heart J Aug;144(2): Sparrow P, Amirabadi A, Sussman MS, Paul N, Merchant N. Quantitative assessment of myocardial T2 relaxation times in cardiac amyloidosis. J Magn Reson Imaging Sep 24;30(5): Maceira AM, Joshi J, Prasad SK, Moon JC, Perugini E, Harding I, et al. Cardiovascular magnetic resonance in cardiac amyloidosis. Circulation Jan 18;111(2): Page 23 of 23