^<13>N-ammonia positron emission tomography-derived left ventricular strain in patients after heart transplantation validated using cardiovascular magnetic resonance feature tracking as reference

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Figure legends

Fig. 1 Semi-automatic strain analysis with feature tracking. The upper images of a to c are

short-axis slices, and the lower images are horizontal long-axis slices. The left column of a

to c shows cardiovascular magnetic resonance images, and the right column shows positron

emission tomography images. (a) The endocardial borders defined manually at the end of

the diastole frame (magenta and green lines). The template images are automatically set,

centered by the points on the borders (yellow squares). (b) Automatic tracking of the points

during the cardiac cycle using a local template-matching technique. (c) The endocardial

borders are automatically contoured as lines with spline interpolation of the tracked points.

(d) Calculation of the systolic strain from the strain curves as the minimum values of the

normalized regional lengths

Fig. 2 Scatter plots and Bland Altman plots between PET-derived strains and CMRderived strains. Graphs of the left column of a to d are shown as black dotted plots of the

strain values. The dashed lines represent approximate lines. Graphs of the right column are

shown as Bland Altman plots. Blue solid lines show bias, and dashed red lines show limits

of agreement. Plots of a to d show the basal, middle, apical, and LS regions, respectively.

PET positron emission tomography, CMR cardiovascular magnetic resonance, CS

circumferential strain, LS longitudinal strain

Fig. 3 Circumferential strains between left ventricular regions. Box whisker plots of the

circumferential strains are shown. PET-derived strains (a) and CMR-derived strains (b) are

23

indicated. Regional circumferential strains are anterior, inferior, septum, and lateral, from

left to right. **p < 0.01, *p < 0.05. PET positron emission tomography, CMR

cardiovascular magnetic resonance

Fig. 4 Colored circumferential strain maps according to left ventricular 16-segments model.

PET-derived strain maps at resting and stress states (a and b) and a CMR-derived strain

map (c

red. PET positron emission tomography, CMR cardiovascular magnetic resonance

Fig. 5 Longitudinal strains between left ventricular regions. Box whisker plots of the

longitudinal strains are shown. PET-derived strains (a) and CMR-derived strains (b) are

indicated. The regional longitudinal strains are the free wall and septum (left and right,

respectively). **p < 0.01, *p < 0.05. PET positron emission tomography, CMR

cardiovascular magnetic resonance

b. Search and Matching for a cardiac cycle

c. Auto contouring of endocardium

d. Strain calculation

Strain (normalized wall length) [%]

a. Manual contouring at end-diastole

-20

Circumferential strain

-40

Longitudinal strain

R-R duration [%]

Fig. 1 Semi-automatic strain analysis with feature-tracking

The upper images of a to c are short-axis slices, and the lower images are

horizontal long-axis slices. The left column of a to c shows cardiovascular

magnetic resonance images, and the right column shows positron emission

tomography images.

(a) The endocardial borders defined manually at the end of the diastole frame

(magenta and green lines). The template images are automatically set, centered

by the points on the borders (yellow squares). (b) Automatic tracking of the

points during the cardiac cycle using a local template-matching technique. (c)

The endocardial borders are automatically contoured as lines with spline

interpolation of the tracked points. (d) Calculation of the systolic strain from

the strain curves as the minimum values of the normalized regional lengths.

Fig. 2 Scatter plots and Bland−Altman plots between PET-derived

strains and CMR derived strains

Graphs of the left column of a to d are shown as black dotted plots of the

strain values. The dashed lines are indicated as approximate lines. Graphs

of the right column are shown as Bland–Altman plots. Blue solid lines

show bias, and dashed red lines show limits of agreement.

Plots of a to d show the basal, middle, apical, and LS regions, respectively.

PET, positron emission tomography; CMR, cardiovascular magnetic

resonance; CS, circumferential strain; LS, longitudinal strain.

Fig. 3 Circumferential strains between left ventricular regions

Box–whisker plots of the circumferential strains are shown. PET-derived strains

(a) and CMR-derived strains (b) are indicated. Regional circumferential strains

are anterior, inferior, septum, and lateral, from left to right.

**p<0.01, *p<0.05. PET, positron emission tomography; CMR, cardiovascular

magnetic resonance.

a. Resting PET

b. Stress PET

Circumferential strain [%]

Circumferential strain [%]

Circumferential strain [%]

c. CMR

Fig. 4 Colored circumferential strain maps according to left ventricular 16segments model

PET-derived strain maps at resting and stress states (a and b) and a CMRderived strain map (c) are indicated. Circumferential strains of −20 % to −30 %

are described in blue to red.

PET, positron emission tomography; CMR, cardiovascular magnetic resonance.

Fig.5 Longitudinal strains between left ventricular regions

Box–whisker plots of the longitudinal strains are shown. PET-derived strains (a)

and CMR-derived strains (b) are indicated. The regional longitudinal strains are

the free wall and septum (left and right, respectively).

**p<0.01, *p<0.05. PET, positron emission tomography; CMR, cardiovascular

magnetic resonance.

TABLE 1

Characteristics

Patients after heart transplantation (n = 15)

Male/Female

P-value

10/5

Age (y)

43 ± 14

WHO classification ( / / / )

10/2/3/0

Years after transplantation

12 ± 8

6/9

PET to CMR duration (day)

LV volume parameters

67 ± 23

PET

CMR

EDV (mL)

79.5 ± 22.9

92.3 ± 18.3

0.002

ESV (mL)

22.3 ± 10.1

44.9 ± 13.7

<0.0001

EF (%)

72.8 ± 6.3

52.0 ± 6.1

<0.0001

PET

CMR

Basal CS (%)

-25.0 ± 3.4

-25.5 ± 3.9

0.49

Middle CS (%)

-25.1 ± 4.8

-23.8 ± 4.6

0.048

Apical CS (%)

-27.2 ± 5.1

-25.8 ± 5.1

0.13

LS (%)

-22.0 ± 1.6

-16.9 ± 1.9

<0.0001

LV strain parameters

HR, heart rate; WHO, world health organization; PET, positron emission tomography; CMR,

cardiovascular magnetic resonance; LV, left ventricular; EDV, end-diastole volume; ESV, end-systole

volume; EF, ejection fraction; CS, circumferential strain; LS, longitudinal strain.

TABLE 2 Parameters of agreement of LV strains and LV volumes

LV strains [%]

Parameter

Correlation

coefficients

Bias (LOA)

SDD

ICC (95% CI)

Basal CS

Middle

CS

LV volumes

EDV

ESV

[mL]

[mL]

0.87**

0.80**

0.87**

0.75**

7.1 (

12.7 (

22.6 (

20.8

10.5,

35.6,

39.1,

(11.9,

3.8)

10.2)

6.1)

30.0)

Apical CS

LS

EF [%]

0.69**

0.80**

0.79**

0.6 ( 5.4,

1.3 (

1.4 (

6.5)

5.8, 3.3)

8.2, 5.3)

3.0

2.3

3.4

1.7

11.7

8.4

4.5

0.69

0.89

0.79

0.85

0.85

0.77

0.75

(0.29

(0.70

(0.47

(0.61

(0.62

(0.45

(0.41

0.88)

0.96)

0.92)

0.95)

0.95)

0.92)

0.91)

CI, confidence interval; CS, circumferential strain; EDV, end-diastolic volume; ESV, end-systolic volume;

EF, ejection fraction; ICC, intraclass correlation coefficient; LOA, limit of agreement; LV, left ventricular;

LS, longitudinal strain; SDD, standard deviation of the difference.

Underlined parameters are normal data distribution.

**p < 0.01.

TABLE 3 Correlation coefficients between circumferential strains and myocardial flow reserves

Stress/Resting

Ratio

Stress PET

Resting PET

CMR

Correlation

coefficients

P-value

Correlation

coefficients

P-value

Correlation

coefficients

P-value

Correlation

coefficients

P-value

Global CS vs.

Global MFR

0.30

0.28

0.02

0.94

0.14

0.62

0.21

0.44

RCA CS vs.

RCA MFR

0.05

0.85

0.07

0.80

0.20

0.48

0.03

0.90

LAD CS vs.

LAD MFR

0.53

0.04

0.20

0.48

0.35

0.20

0.37

0.18

LCx CS vs.

LCx MFR

0.32

0.25

0.08

0.77

0.09

0.74

0.07

0.80

due to data non-normal distribution were expressed with underline.

PET, positron emission tomography; CMR, cardiovascular magnetic resonance; CS, circumferential

strain, MFR; myocardial flow reserve; RCA, right coronary artery; LAD, left anterior descending artery;

LCx, left circumflex coronary artery.

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