Clinical evaluation of two dark blood methods of late gadolinium quantification of ischemic scar

Abstract

Background Late gadolinium enhancement (LGE) imaging was validated for diagnosis and quantification of myocardial infarction (MI). Despite good contrast between scar and normal myocardium, contrast between blood pool and myocardial scar can be limited. Dark blood LGE sequences attempt to overcome this issue. Purpose To evaluate T1 rho (T1ρ)‐prepared dark blood sequence and compare to blood nulled (BN) phase sensitive inversion recovery (PSIR) and standard myocardium nulled (MN) PSIR for detection and quantification of scar. Study Type Prospective. Population Thirty patients with prior MI. Field Strength/Sequence Patients underwent identical 1.5 T MRI protocols. Following routine LGE imaging, a slice with scar, remote myocardium, and blood pool was selected. PSIR LGE was repeated with inversion time set to MN, to BN, and T1ρ FIDDLE (flow‐independent dark‐blood delayed enhancement) in random order. Assessment Three observers. Qualitative assessment of confidence scores in scar detection and degree of transmurality. Quantitative assessment of myocardial scar mass (grams), and contrast‐to‐noise ratio (CNR) measurements between scar, blood pool, and myocardium. Statistical Tests Repeated‐measures analysis of variance (ANOVA) with Bonferroni correction, coefficient of variation, and the Cohen κ statistic. Results CNRscar‐blood was significantly increased for both BN (27.1 ± 10.4) and T1ρ (30.2 ± 15.1) compared with MN (15.3 ± 8.4 P < 0.001 for both sequences). There was no significant difference in CNRscar‐myo between BN (55.9 ± 17.3) and MN (51.1 ± 17.8 P = 0.512); both had significantly higher CNRscar‐myo compared with the T1ρ (42.6 ± 16.9 P = 0.007 and P = 0.014, respectively). No significant difference in scar size between LGE methods: MN (2.28 ± 1.58 g) BN (2.16 ± 1.57 g) and T1ρ (2.29 ± 2.5 g). Confidence scores were significantly higher for BN (3.87 ± 0.346) compared with MN (3.1 ± 0.76 P < 0.001) and T1ρ (3.20 ± 0.71 P < 0.001). Data Conclusion PSIR with inversion time (TI) set for blood nulling and the T1ρ LGE sequence demonstrated significantly higher scar to blood CNR compared with routine MN. PSIR with TI set for blood nulling demonstrated significantly higher reader confidence scores compared with routine MN and T1ρ LGE, suggesting routine adoption of a BN PSIR approach might be appropriate for LGE imaging. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:146–152.

Dark-blood late gadolinium enhancement cardiovascular magnetic resonance for improved detection of subendocardial scar: a review of current techniques

“…Differences in sensitivity and accuracy further increased when only slices with < 25% transmural infarction were considered (98 and 95% vs 80 and 85%, respectively). Although Foley et al found a 37.5% larger transmural extent of scar using dark-blood LGE compared to conventional LGE, no significant difference between both techniques was reported when using the full-width half-maximum (FWHM) quantification method [ 24 ]. This method, however, was found to under-estimate dark-blood LGE scar size by over 25% [ 28 ].…”

“…While most novel dark-blood methods are compared to conventional LGE, only FIDDLE and blood-nulled PSIR LGE have been validated against histology [ 14 , 26 ], and direct comparison studies evaluating different dark-blood LGE methods are limited [ 24 ]. Such comparison studies are mostly hindered by the limited availability of most techniques.…”

“…Also in 2019, Foley et al performed a study in which this blood-nulled PSIR LGE was compared against T 1 -rho FIDDLE and conventional LGE in a cohort of thirty patients with confirmed prior MI [24]. While both Fig.…”

“…Also in 2019, Foley et al performed a study in which this blood-nulled PSIR LGE was compared against T 1 -rho FIDDLE and conventional LGE in a cohort of thirty patients with confirmed prior MI [ 24 ]. While both blood-nulled LGE and T 1 -rho FIDDLE showed increased scar-to-blood contrast, only blood-nulled LGE was able to simultaneously maintain, and even exceed, scar-to-myocardium contrast compared to conventional LGE.…”

Clinical value of dark-blood late gadolinium enhancement cardiovascular magnetic resonance without additional magnetization preparation

“…However, a potential disadvantage of these dark- and black-blood methods is the decrease in scar-to-myocardium contrast, potentially compromising the detection of non-ischemic scar compared to bright-blood LGE [31]. In contrast, dark-blood LGE without magnetization preparation is able to maintain, or even exceed, the scar-to-myocardium contrast of conventional LGE, in addition to its superior scar-to-blood contrast [32].…”