European Nuclear Medicine Guide
Based on the clearance of individual tracers, multiple injections can be made during a single study. By using 99mTc-labelled RBCs or HSA, first-pass radionuclide ventriculography (FPRNV) can be performed just before ERNV (methods for the process of labelling of RBCs are described in ERNV procedure). By injecting technetium-99m labelled perfusion agents, it is possible to also acquire, after the FPRNA, a myocardial perfusion SPECT.
FPRNA can be used to:
The use of FPRNA for the evaluation of cardiac function is currently reduced due to the availability of Echocardiography. First-pass angiography allows accurate evaluation of RV function, detection and quantification of intrOacardiac shunts, and analysis of both function and perfusion when a perfusion tracer is injected.
Assessment of diastolic function has achieved increasing importance with clinical recognition of congestive heart failure associated with normal systolic and abnormal diastolic function. Several parameters which can be derived from FPRNA, such as peak filling rate and time-to-peak filling rate, allow evaluation of diastolic function of the ventricles.
For adults, the range of the administered activities is 555-1110 MBq for any 99mTc-labelled tracer. In paediatric nuclear medicine, the activities should be modified according to the EANM paediatric dosage card (https://www.eanm.org/publications/dosage-calculator/). The minimum recommended activity is 80 MBq except for 99mTc-DTPA (34 MBq).
The effective doses per administered activity are [3]:
Caveat
“Effective Dose” is a protection quantity that provides a dose value related to the probability of health detriment to an adult reference person due to stochastic effects from exposure to low doses of ionizing radiation. It should not be used to quantify the radiation risk for a single individual associated with a particular nuclear medicine examination. It is used to characterize a certain examination in comparison to alternatives, but it should be emphasized that if the actual risk to a certain patient population is to be assessed, it is mandatory to apply risk factors (per mSv) that are appropriate for the gender, the age distribution and the disease state of that population."
The interpretation of first-pass data should be performed paying particular attention to the quality of the data. The final representative cardiac cycle used to generate both quantitative results and the qualitative wall motion assessment can be affected by many factors including the adequacy of the injection bolus, the count rate, the number and type of beats chosen for inclusion, the manner in which background activity is determined, and patient motion.
The most common position used is the semi supine, straight anterior view. This position allows an easy position of the chest against the detector, and the LV will easily be in the field of view. The pulmonary background is also reduced in this position, and thereby enhances study quality.
However, in the anterior view there is the anatomic overlap that could occur with the descending aorta and the basal portion of the inferoseptal wall and with the left atrium and the basal portion of the LV. The right oblique orientation (ROA) view helps eliminate both those sources of overlap and enhances right atrial-RV separation for the measurement of RV EF. The injection technique is critical. Rapid injection of a small volume of radiotracer into a large proximal vein or through large-gauge intravenous access in an antecubital vein followed by a saline flush is necessary for optimal results. If the bolus is suboptimal, the results might not be valid. Bolus adequacy can be measured by superior vena cava bolus analysis.
The detailed recommendations regarding the modality of acquisition of radionuclide ventriculography are available in the ASNC Clinical Guidelines and Quality Standards Documents.