Figure 1
Semi-quantitative myocardial perfusion magnetic resonance imaging analysis.
Detailed steps for semi-quantitative perfusion magnetic resonance imaging (MRI) analysis in a 69-year-old patient with intermediate-grade stenosis of the mid portion of the left anterior descending artery on both coronary computed tomography angiography and catheter coronary angiography (not shown).
Peak myocardial enhancement on adenosine perfusion MRI showed a septal and anterior wall mid-left ventricular area of low signal intensity (white arrow, segment 7 in Figure 1A) in the area-at-risk (RISK), whereas the remote area (REMOTE) (arrowhead, segment 10 in Figure 1A) was homogenously enhanced. No abnormal enhancement was present on late-enhancement imaging (not shown).
Equally divided subendocardial (bold lines, END) and subepicardial (thin lines, EPI) regions of interest are drawn in the RISK (red color) and REMOTE segments (blue color) after outlining the endocardial and epicardial borders of the myocardium during maximal hyperemia (Figure 1B). After extending these regions of interest to the whole frames, corresponding time-signal intensity curves and the maximal upslope value of the contrast enhancement were obtained (Figures 1C).
RISK = myocardium beyond stenosis; REMOTE = remote myocardium; [END] = subendocardial; [EPI] = subepicardial; S= adenosine stress imaging.
Figure 2
Study flowchart.
CCTA = coronary computed tomography angiography; CCA = catheter coronary angiography; QCA = quantitative coronary angiography; FFR = fractional flow reserve; MRI = magnetic resonance imaging.
Table 1
Patient demographics and cardiovascular risk factors.
| PATIENT CHARACTERISTICS | NON ISCHEMIC (n = 31) | ISCHEMIC (n = 15) |
|---|---|---|
| Age (years)* | 61 ± 9 [44–80] | 62 ± 9 [48–80] |
| Ratio M/F | 22/9 | 11/4 |
| BMI (kg/m2)* | 29 ± 5 [21–39] | 27 ± 3 [24–35] |
| Resting heart rate (beats per minute)* | 68 ± 13 [51–100] | 67 ± 8 [54–81] |
| Family history of coronary disease | 9 (29%) | 3 (20%) |
| Personal history of coronary disease | 3 (10%) | 5 (33%) |
| Diabetes mellitus | 10 (32%) | 2 (13%) |
| Current tobacco smoker | 10 (32%) | 7 (47%) |
| Elevated blood lipid profile | 23 (74%) | 13 (87%) |
| Systemic hypertension | 25 (80%) | 8 (53%) |
| Agatston coronary calcium score** | 225 [139–480] | 465 [109–578] |
[i] * Mean ± standard deviation [range].
** 4 males with coronary stenting excluded.
M = male; F = female
Table 2
Segmental topography of 49 intermediate-grade coronary artery stenosis.
| LOCATION | n (%) |
|---|---|
| Right coronary artery | 12 (24.5) |
| Proximal segment | 3 (6.1) |
| Mid segment | 7 (14.3) |
| Distal segment | 2 (4.1) |
| Left main trunk | 1 (2) |
| Left anterior descending coronary artery | 28 (57.2) |
| Proximal segment | 14 (28.6) |
| Mid segment | 14 (28.6) |
| Left circumflex coronary artery | 7 (14.3) |
| Proximal segment | 3 (6.1) |
| Mid segment | 2 (4.1) |
| Distal segment | 2 (4.1) |
| Marginal branch | 1 (2) |
| First branch | 1 (2) |
Table 3
Diagnostic values of visual and semi-quantitative analysis of adenosine perfusion MRI for FFR ≤ 0.80 intermediate-grade coronary artery stenoses.
| INTERMEDIATE STENOSES (n = 49) | TP | TN | FP | FN | SENSITIVITY | SPECIFICITY | PPV | NPV | LR+ | LR– | ACCURACY |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Visual consensus reading 1 | 11 | 29 | 5 | 4 | (11/15) 73% | (29/34) 85% | (11/16) 69% | (29/33) 87% | 4.99 | 0.31 | (40/49) 82% |
| Visual consensus reading 2 | 9 | 31 | 3 | 6 | (9/15) 60% | (31/34) 91% | (9/12) 84% | (31/37) 84% | 6.80 | 0.44 | (40/49) 82% |
| Relative myocardial perfusion | 12 | 31 | 3 | 3 | (12/15) 80% | (31/34) 91% | (12/15) 80% | (31/34) 91% | 4.56 | 0.11 | (43/49) 88% |
[i] The proportions by which the percentages were calculated are given in parentheses.
TP = true positive; TN = true negative; FP = false positive; FN = false negative; MRI = magnetic resonance imaging; FFR = fractional flow reserve; PPV = positive predictive value; NPV = negative predictive value; LR = likelihood ratio; relative myocardial perfusion = stress subendocardial relative myocardial perfusion index.
Table 4
Semi-quantitative subendocardial stress enhancement parameters in RISK and REMOTE myocardium during adenosine perfusion in patients with ischemic and non-ischemic intermediate coronary artery stenosis (as defined by the 0.8 FFR cut-off value).
| SUBENDOCARDIAL STRESS ENHANCEMENT PARAMETER | ISCHEMIC (FFR ≤0.80, n = 15) | NON-ISCHEMIC (FFR > 0.80, n = 31) |
|---|---|---|
| Mean maximal upslope in RISK myocardium* | 0.16 ± 0.04 [0.11–0.24] | 0.18 ± 0.05 [0.07–0.29] |
| Mean maximal upslope in REMOTE myocardium* | 0.20 ± 0.04 [0.13–0.26] | 0.18 ± 0.04 [0.09–0.28] |
| RMPI | 0.79 ± 0.14 [0.57–1.05] | 1.01 ± 0.13 [0.81–1.39] |
[i] Values are given as mean ± standard deviation [range].
* Maximal upslopes are normalized by the corresponding left ventricle cavity enhancement upslope; RISK = myocardium beyond stenosis; REMOTE = remote myocardium; RMPI = relative myocardial perfusion index; FFR = fractional flow reserve.