Native T1 mapping in patients with idiopathic dilated cardiomyopathy for the assessment of diffuse myocardial fibrosis: validation against histologic endomyocardial biopsy

Introduction: Diffuse myocardial fibrosis (DFM) is the major mechanism in the pathophysiology of the aortic stenosis and its complications. DMF is detectable by magnetic resonance imaging (MRI) using the T1 mapping technique. Hypothesis: The MRI derived native T1 relaxation time and myocardial extracellular volume fraction (ECV) will be significantly related to the extent of DMF et targeted myocardial left ventricular (LV) biopsy. Methods: The study population consisted of 40 consecutive patients (age 63±8y, 65% males) undergoing surgery for severe aortic stenosis (77.5%), aortic root dilatation (7.5%) or valve regurgitation (15%). All patients underwent MRI-derived T1 mapping and 2D-, 3D speckle tracking-derived strain analysis prior to surgery. The T1 relaxation time was assessed in basal interventricular septum pre and 10 min post contrast administration using the modified Look-Locker Inversion recovery sequence. A LV myocardial biopsy specimen was obtained during surgery from basal interventricular septum under the guidance of the MRI operator to assure spatial concordance with the MRI assessment. The percentage of myocardial collagen was quantified as a ratio of Picrosirius Red-positive area over total sample area using the Image J. Results: The average percentage of myocardial collagen was 22 ± 14.8 %. The average native T1 relaxation time and ECV was 1010 ± 48 ms and 0.288 ± 0.055, respectively. Both native T1 relaxation time with cutoff value of ≥ 1010 ms (Ss=90%, Sp=73%, AUC =0.82) and ECV with cutoff value of ≥ 0.315 (Ss=80%, Sp=90%, AUC =0.85) showed high accuracy to identify extensive (> 30%) myocardial collagen content (Figure 1A, 1B). The native T1 mapping showed significant correlation with LV mass, 2D and 3D global longitudinal strain (all p<0.05) while the ECV did not (p=NS). Conclusions: Native T1 relaxation time is the accurate marker of diffuse myocardial fibrosis with the significant relationship with LV morphology and myocardial function.

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Abstract 15137: Detection of Diffuse Myocardial Fibrosis using Multi-slice T1 Mapping by Slice Interleaved T1 (STONE) Sequence in Patients With Hypertrophic Cardiomyopathy

Circulation ◽

10.1161/circ.132.suppl_3.15137 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Shingo Kato ◽

Sébastien Roujol ◽

Jihye Jang ◽

Tamer Basha ◽

Sophie Berg ◽

...

Keyword(s):

Hypertrophic Cardiomyopathy ◽

Myocardial Fibrosis ◽

Wall Thickness ◽

T1 Mapping ◽

Free Breathing ◽

Left Ventricular ◽

Diffuse Myocardial Fibrosis ◽

Mapping Technique ◽

Native T1 ◽

Native T1 Time

Introduction: In hypertrophic cardiomyopathy (HCM), there are significant variations in left ventricular (LV) wall thickness and fibrosis, which necessitates a volumetric coverage. Slice-interleaved T1 (STONE) mapping sequence allows for the assessment of native T1 time with complete coverage of LV myocardium. Hypothesis: We hypothesized that STONE sequence is useful for the assessment of regional native T1 time abnormality in HCM patients. Methods: Twenty-four septal HCM patients (56±16 years) and 10 healthy adult control subjects (57±15 years) were studied. Native T1 mapping was performed using STONE sequence which enables acquisition of 5 slices in the short-axis plane within a 90 sec free-breathing scan. We measured LV native T1 time and maximum LV wall thickness in each 16 segments from 3 slices (basal-, mid- and apical-slice) and evaluated the relationship between LV native T1 time and wall thickness. Late gadolinium enhanced (LGE) MRI was acquired to assess presence of myocardial enhancement. Results: In HCM patients, LV native T1 time was significantly elevated compared to healthy controls, regardless of presence or absence of LGE (mean native T1 time; LGE (+) segments (n=27), 1139±55 msec; LGE (-) segments (n=351), 1118±55 msec; healthy control (n=160),1065±35 msec; p<0.001 by one-way ANOVA, 6 segments were excluded from analysis due to artifacts). Among 351 segments without LGE, native LV T1 time was diffusely elevated over the 16 segments (Figure). Significant positive correlation was found between LV wall thickness and native LV T1 time (y=1013+8.7x, p<0.001). Conclusions: In HCM, substantial number of segments without LGE showed elevated native T1 time, and native T1 time was correlated with LV wall thickness. Multi-slice T1 mapping by using STONE sequence could be advantageous to overcome limited cardiac coverage of conventional single-slice T1 mapping technique and to accurately detect the diffuse myocardial fibrosis in HCM patients.

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Faculty Opinions recommendation of Effects of myocardial fibrosis and ventricular dyssynchrony on response to therapy in new-presentation idiopathic dilated cardiomyopathy: insights from cardiovascular magnetic resonance and echocardiography.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13436984.14811088 ◽

2012 ◽

Author(s):

Marco Metra ◽

Luca Bettari

Keyword(s):

Cardiovascular Magnetic Resonance ◽

Magnetic Resonance ◽

Dilated Cardiomyopathy ◽

Myocardial Fibrosis ◽

Response To Therapy ◽

Idiopathic Dilated Cardiomyopathy ◽

Ventricular Dyssynchrony

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