Transient Ischemic Dilation - A New Definition [oral presentation]. 2005 American College of Nuclear Physicians Annual Meeting

8/3/2019 Transient Ischemic Dilation - A New Definition [oral presentation]. 2005 American College of Nuclear Physicians Annual Meeting.

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The Bitterroot Mountains From Kellogg Peak

Necessity is the Mother of Invention.

- Plato



Defining Transient Ischemic Dilation

• Background

• Methods

• Results• Conclusion





Transient Ischemic Dilation

“As such, the volumes associated with this

measurement should not be considered to

represent either end-systolic or end-

diastolic volumes alone but rather acomplex average of the two.”

Dan Berman, Rory Hachamovitch, Guido Germano and others,

as quoted in the J Nucl Med. 2004 Dec;45(12):1999-2007.



Transient Ischemic Dilation



Defining the “Complex Average”

• What is the contribution of the ESV?

• What is the contribution of the EDV?

• Can this complex average be derived fromthe gated SPECT data?



“When you cannot explain it in

numbers, your knowledge is of ameager and unsatisfactory kind.”

– Lord Kelvin (William Thomson, 1824-1907)




• Background

• Methods

• Results

• Conclusion



Methods

• Retrospective review of 422 consecutive

patients

• Ischemia determined semi-quantitatively

using a 17 segment, 5 point scale

• Post-stress to rest ventricular volume

ratios correlated with ischemia




• Background

• Methods

• Results

• Conclusion



Ventricular Volume Ratios

- 0.04 *0.08 **0.18 **Difference

1.060.920.84Ischemia –

1.021.001.02Ischemia +

LVEFrEDVrESVr

** p < 0.01, * p < 0.05 for the presence or absence of ischemia usingthe independent samples t-test



Pearson Correlation Coefficients

-0.112 *0.227 **0.259 **Ischemia

LVEFrEDVrESVr

** p < 0.01, * p < 0.05



Partial Correlation Coefficients

Corrected for Type of Stress

-0.1239 *0.2252 **0.2560 **Ischemia

LVEFrEDVrESVr

** p < 0.001, * p < 0.05




Corrected for Type of Stress and Sex

-0.1319 *0.2092 **0.2504 **Ischemia

LVEFrEDVrESVr

** p < 0.001, * p < 0.05




Corrected for Type of Stress, Sex, and Age

-0.1191 *0.2085 **0.2427 **Ischemia

LVEFrEDVrESVr

** p < 0.001, * p < 0.05



Optimization

• Both the ESV and EDV contain significant

correlations

• The ESV is more highly correlated than is

the EDV

• The contribution of the ESV is greater than

that of the EDV to the TID ratio



Optimization

stress (ESV * X + EDV)

rest (ESV * X + EDV)

where X = the ESV weighing factor

What value of X will lead to the highest correlation with myocardial ischemia?




Controlling for Type of Stress

0.2738 **0.2761 **0.2252 **Ischemia

X = 10X = 5X = 0

stress (ESV*X + EDV) / rest (ESV*X + EDV)

where X = the ESV weighing factor

** p < 0.001




0.2

0.22

0.24

0.26

0.28

0 5 10 15 20 25 30 35 40

ESV Weighing Factor

C o r r e l a

t i o n

C o e f f i e n t

Ischemia SDS




0.2754

0.2756

0.2758

0.276

0.2762

3.4 3.8 4.2 4.6 5 5.4 5.8 6.2

ESV Weighing Factor

C o r r e l a

t i o n C

o e f f i c i e n t

Ischemia



Linear Regression

30.885

30.89

30.895

30.9

30.905

4.5 5.0 5.5

ESV Weighing Factor

F S

c o r e

F Score




• Background

• Methods

• Results

• Conclusion



Conclusion

• The ESVr, EDVr, and LVEFr all are significantly

correlated with myocardial ischemia

• The ESVr is more highly correlated with

myocardial ischemia than the EDVr or LVEFr

• The stress (ESVx5 + EDV) / rest (ESVx5 + EDV)

has the strongest correlation with myocardial

ischemia



The “Complex Average” ?

stress ESV * 5 + stress EDVstress ESV * 5 + stress EDV

rest ESV * 5 + rest EDVrest ESV * 5 + rest EDV

Documents

Transient Ischemic Dilation - A New Definition [oral presentation]. 2005 American College of Nuclear Physicians Annual Meeting