First Pass Radionuclide Angiography (FPRNA)
First Pass Radionuclide Angiography (FPRNA) is a form of radionuclide angiocardiography in which a rapid sequence of images is taken immediately after administration of a bolus of radionuclide, recording only the initial transit of the isotope through the central circulation.
Equilibrium Gated Radionuclide Angiography (ERNA)
Equilibrium Gated Radionuclide Angiography (ERNA) is a form of radionuclide angiocardiography in which images are taken at specific phases of the cardiac cycle over a series of several hundred cycles. Timing of image recording is set, or gated, by the occurrence of specific electrocardiographic waveforms, and the data can be used to determine average activity during specific cardiac cycle phases or can be accumulated and displayed in rapid sequence, as a movie.
First-pass Radionuclide Angiography (FPRNA), Equilibrium Gated
Radionuclide Angiography (ERNA)
Three-camera imaging techniques are available to measure the ventricular function first-pass radionuclide angiography (FPRNA), equilibrium gated radionuclide angiography (ERNA), and GSPECT. During FPRNA, a dynamic bolus of radioactivity is imaged as it quickly transits through different chambers of the heart and lungs. It is a preferred technique for the assessment of peak-exercise ventricular function, and measurement of the right ventricular (RV) function. Both acquisitions of ERNA and GSPECT are synchronized with the patient’s ECG.
During an ERNA study, a blood-pool agent such as 99mTc-labeled erythrocytes is injected and images are acquired over many hundreds of heartbeats. Ventricular cavity counts are used to generate a time–activity curve, from which functional parameters are derived.There are fundamental differences between these procedures and GSPECT. During a GSPECT study, a perfusion tracer is injected which is taken up by the LV myocardium. Definition of the LV myocardium and LV cavity is achieved by delineating the epicardial and endocardial edges on the perfusion image. LV global and regional contractile function is quantitated based on the changes in the LV volume, excursion of the endocardium, and brightening of the myocardium from the end-diastolic image to the end-systolic image, as identified by the ECG. Because RV myocardium is not adequately visualized on the perfusion images, GSPECT is not suitable for accurate RV function measurement.
ERNA has been used as a standard technique for ventricular function measurements for many years. Despite its accuracy and reproducibility, there has been a decline in this procedure in recent years, mainly because of the widespread availability of echocardiography in clinical settings.
General Principles
Framing; Heartbeat Variation and Tolerance
In routine practice, acquisition of 24-32 frames per cardiac cycle is considered satisfactory. The computer determines the length of the cardiac cycle based on the average of multiple R–R intervals before the acquisition. A range of acceptable beats (“acceptance window”) is specified.This is known as “tolerance” and is expressed as the per centage of the mean R–R interval.
Quantitation
LV volume is calculated by multiplying the number of pixels within the LV cavity with the size of a pixel. LV volume can be generated for each of the frames in the cardiac cycle. The largest volume and the smallest volume represent the end-diastolic volume (EDV) and the end-systolic volume (ESV), respectively. LVEF is derived from the volumes using the formula (EDV –ESV)/EDV x 100.
Once the endocardial edge is detected, regional endocardial wall motion (RWM) can be quantitated by computing the distance of a given point on the endocardial surface between end- diastole and end-systole.
First Pass Radionuclide Angiography (FPRNA) is a form of radionuclide angiocardiography in which a rapid sequence of images is taken immediately after administration of a bolus of radionuclide, recording only the initial transit of the isotope through the central circulation.
Equilibrium Gated Radionuclide Angiography (ERNA)
Equilibrium Gated Radionuclide Angiography (ERNA) is a form of radionuclide angiocardiography in which images are taken at specific phases of the cardiac cycle over a series of several hundred cycles. Timing of image recording is set, or gated, by the occurrence of specific electrocardiographic waveforms, and the data can be used to determine average activity during specific cardiac cycle phases or can be accumulated and displayed in rapid sequence, as a movie.
First-pass Radionuclide Angiography (FPRNA), Equilibrium Gated
Radionuclide Angiography (ERNA)
Three-camera imaging techniques are available to measure the ventricular function first-pass radionuclide angiography (FPRNA), equilibrium gated radionuclide angiography (ERNA), and GSPECT. During FPRNA, a dynamic bolus of radioactivity is imaged as it quickly transits through different chambers of the heart and lungs. It is a preferred technique for the assessment of peak-exercise ventricular function, and measurement of the right ventricular (RV) function. Both acquisitions of ERNA and GSPECT are synchronized with the patient’s ECG.
During an ERNA study, a blood-pool agent such as 99mTc-labeled erythrocytes is injected and images are acquired over many hundreds of heartbeats. Ventricular cavity counts are used to generate a time–activity curve, from which functional parameters are derived.There are fundamental differences between these procedures and GSPECT. During a GSPECT study, a perfusion tracer is injected which is taken up by the LV myocardium. Definition of the LV myocardium and LV cavity is achieved by delineating the epicardial and endocardial edges on the perfusion image. LV global and regional contractile function is quantitated based on the changes in the LV volume, excursion of the endocardium, and brightening of the myocardium from the end-diastolic image to the end-systolic image, as identified by the ECG. Because RV myocardium is not adequately visualized on the perfusion images, GSPECT is not suitable for accurate RV function measurement.
ERNA has been used as a standard technique for ventricular function measurements for many years. Despite its accuracy and reproducibility, there has been a decline in this procedure in recent years, mainly because of the widespread availability of echocardiography in clinical settings.
General Principles
Framing; Heartbeat Variation and Tolerance
In routine practice, acquisition of 24-32 frames per cardiac cycle is considered satisfactory. The computer determines the length of the cardiac cycle based on the average of multiple R–R intervals before the acquisition. A range of acceptable beats (“acceptance window”) is specified.This is known as “tolerance” and is expressed as the per centage of the mean R–R interval.
Quantitation
LV volume is calculated by multiplying the number of pixels within the LV cavity with the size of a pixel. LV volume can be generated for each of the frames in the cardiac cycle. The largest volume and the smallest volume represent the end-diastolic volume (EDV) and the end-systolic volume (ESV), respectively. LVEF is derived from the volumes using the formula (EDV –ESV)/EDV x 100.
Once the endocardial edge is detected, regional endocardial wall motion (RWM) can be quantitated by computing the distance of a given point on the endocardial surface between end- diastole and end-systole.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.