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Respiratory motion detection and correction in ECG-gated SPECT: a new approach.

Bitarafan A, Rajabi H, Gruy B, Rustgou F, Sharafi AA, Firoozabady H, Yaghoobi N, Malek H, Pirich C, Langesteger W, Beheshti M - Korean J Radiol (2008 Nov-Dec)

Bottom Line: The percentages of tracer intensity in the inferior, inferoseptal and septal walls as well as the inferior to lateral (I/L) uptake ratio was significantly higher with the use of RC-GSPECT as compared to the use of GSPECT (p < 0.01).Respiratory induced motion can be successfully corrected simultaneously with the use of ECG-gated SPECT in MPI studies using this proposed technique.However, the effect of respiratory correction depends mainly on the patient respiratory pattern and may be clinically relevant in certain cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics, School of Medical Sciences Tarbiat Modares University, Tehran, Iran.

ABSTRACT

Objective: Gated myocardial perfusion single-photon emission computed tomography (GSPECT) has been established as an accurate and reproducible diagnostic and prognostic technique for the assessment of myocardial perfusion and function. Respiratory motion is among the major factors that may affect the quality of myocardial perfusion imaging (MPI) and consequently the accuracy of the examination. In this study, we have proposed a new approach for the tracking of respiratory motion and the correction of unwanted respiratory motion by the use of respiratory-cardiac gated-SPECT (RC-GSPECT). In addition, we have evaluated the use of RC-GSPECT for quantitative and visual assessment of myocardial perfusion and function.

Materials and methods: Twenty-six patients with known or suspected coronary artery disease (CAD)-underwent two-day stress and rest (99m)Tc-Tetrofosmin myocardial scintigraphy using both conventional GSPECT and RC-GSPECT methods. The respiratory signals were induced by use of a CT real-time position management (RPM) respiratory gating interface. A PIO-D144 card, which is transistor-transistor logic (TTL) compatible, was used as the input interface for simultaneous detection of both ECG and respiration signals.

Results: A total of 26 patients with known or suspected CAD were examined in this study. Stress and rest myocardial respiratory motion in the vertical direction was 8.8-16.6 mm (mean, 12.4 +/- 2.9 mm) and 7.8-11.8 mm (mean, 9.5 +/- 1.6 mm), respectively. The percentages of tracer intensity in the inferior, inferoseptal and septal walls as well as the inferior to lateral (I/L) uptake ratio was significantly higher with the use of RC-GSPECT as compared to the use of GSPECT (p < 0.01). In a left ventricular ejection fraction (LVEF) correlation analysis between the use of rest GSPECT and RC-GSPECT with echocardiography, better correlation was noted between RC-GSPECT and echocardiography as compared with the use of GSPECT (y = 0.9654x + 1.6514; r = 0.93, p < 0.001 versus y = 0.8046x + 5.1704; r = 0.89, p < 0.001). Nineteen (19/26) patients (73.1%) showed abnormal myocardial perfusion scans with reversible regional myocardial defects; of the 19 patients, 14 (14/26) patients underwent coronary angiography.

Conclusion: Respiratory induced motion can be successfully corrected simultaneously with the use of ECG-gated SPECT in MPI studies using this proposed technique. Moreover, the use of ECG-gated SPECT improved image quality, especially in the inferior and septal regions that are mostly affected by diaphragmatic attenuation. However, the effect of respiratory correction depends mainly on the patient respiratory pattern and may be clinically relevant in certain cases.

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Related in: MedlinePlus

Flowchart of respiratory-cardiac gated single-photon emission computed tomography (RC-GSPECT).
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Figure 2: Flowchart of respiratory-cardiac gated single-photon emission computed tomography (RC-GSPECT).

Mentions: The RPM system and the Varian unit have an X-ray synchronized interface. Since X-ray synchronization is not possible in respiratory ECG gated SPECT acquisition, we changed the Varian output unit to display the respiratory waves on an oscilloscope. A PIO-D144 card, which is transistor-transistor logic (TTL) compatible, was used as an input interface for simultaneous detection of both ECG and respiration signals. The ECG and respiratory cycles were detected by the TTL program on the PIO-D144 input to control the output of the ECG cycles according to the respiratory cycles. If TTL was on low level (on), the ECG cycle was accepted; otherwise, it was rejected (Fig. 1). Therefore, the ECG monitor and the RPM camera were connected to the synchronization computer and the output of this computer was set up for connection to the gamma camera (Fig. 2).


Respiratory motion detection and correction in ECG-gated SPECT: a new approach.

Bitarafan A, Rajabi H, Gruy B, Rustgou F, Sharafi AA, Firoozabady H, Yaghoobi N, Malek H, Pirich C, Langesteger W, Beheshti M - Korean J Radiol (2008 Nov-Dec)

Flowchart of respiratory-cardiac gated single-photon emission computed tomography (RC-GSPECT).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2627236&req=5

Figure 2: Flowchart of respiratory-cardiac gated single-photon emission computed tomography (RC-GSPECT).
Mentions: The RPM system and the Varian unit have an X-ray synchronized interface. Since X-ray synchronization is not possible in respiratory ECG gated SPECT acquisition, we changed the Varian output unit to display the respiratory waves on an oscilloscope. A PIO-D144 card, which is transistor-transistor logic (TTL) compatible, was used as an input interface for simultaneous detection of both ECG and respiration signals. The ECG and respiratory cycles were detected by the TTL program on the PIO-D144 input to control the output of the ECG cycles according to the respiratory cycles. If TTL was on low level (on), the ECG cycle was accepted; otherwise, it was rejected (Fig. 1). Therefore, the ECG monitor and the RPM camera were connected to the synchronization computer and the output of this computer was set up for connection to the gamma camera (Fig. 2).

Bottom Line: The percentages of tracer intensity in the inferior, inferoseptal and septal walls as well as the inferior to lateral (I/L) uptake ratio was significantly higher with the use of RC-GSPECT as compared to the use of GSPECT (p < 0.01).Respiratory induced motion can be successfully corrected simultaneously with the use of ECG-gated SPECT in MPI studies using this proposed technique.However, the effect of respiratory correction depends mainly on the patient respiratory pattern and may be clinically relevant in certain cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics, School of Medical Sciences Tarbiat Modares University, Tehran, Iran.

ABSTRACT

Objective: Gated myocardial perfusion single-photon emission computed tomography (GSPECT) has been established as an accurate and reproducible diagnostic and prognostic technique for the assessment of myocardial perfusion and function. Respiratory motion is among the major factors that may affect the quality of myocardial perfusion imaging (MPI) and consequently the accuracy of the examination. In this study, we have proposed a new approach for the tracking of respiratory motion and the correction of unwanted respiratory motion by the use of respiratory-cardiac gated-SPECT (RC-GSPECT). In addition, we have evaluated the use of RC-GSPECT for quantitative and visual assessment of myocardial perfusion and function.

Materials and methods: Twenty-six patients with known or suspected coronary artery disease (CAD)-underwent two-day stress and rest (99m)Tc-Tetrofosmin myocardial scintigraphy using both conventional GSPECT and RC-GSPECT methods. The respiratory signals were induced by use of a CT real-time position management (RPM) respiratory gating interface. A PIO-D144 card, which is transistor-transistor logic (TTL) compatible, was used as the input interface for simultaneous detection of both ECG and respiration signals.

Results: A total of 26 patients with known or suspected CAD were examined in this study. Stress and rest myocardial respiratory motion in the vertical direction was 8.8-16.6 mm (mean, 12.4 +/- 2.9 mm) and 7.8-11.8 mm (mean, 9.5 +/- 1.6 mm), respectively. The percentages of tracer intensity in the inferior, inferoseptal and septal walls as well as the inferior to lateral (I/L) uptake ratio was significantly higher with the use of RC-GSPECT as compared to the use of GSPECT (p < 0.01). In a left ventricular ejection fraction (LVEF) correlation analysis between the use of rest GSPECT and RC-GSPECT with echocardiography, better correlation was noted between RC-GSPECT and echocardiography as compared with the use of GSPECT (y = 0.9654x + 1.6514; r = 0.93, p < 0.001 versus y = 0.8046x + 5.1704; r = 0.89, p < 0.001). Nineteen (19/26) patients (73.1%) showed abnormal myocardial perfusion scans with reversible regional myocardial defects; of the 19 patients, 14 (14/26) patients underwent coronary angiography.

Conclusion: Respiratory induced motion can be successfully corrected simultaneously with the use of ECG-gated SPECT in MPI studies using this proposed technique. Moreover, the use of ECG-gated SPECT improved image quality, especially in the inferior and septal regions that are mostly affected by diaphragmatic attenuation. However, the effect of respiratory correction depends mainly on the patient respiratory pattern and may be clinically relevant in certain cases.

Show MeSH
Related in: MedlinePlus