Feasibility of scintigraphy in exercise-induced pulmonary haemorrhage detection and quantification: preliminary studies.

The study explores the use of scintigraphy—an imaging technique used to visualize anatomic structures—for detecting and quantifying an exercise-induced condition known as pulmonary haemorrhage in horses. The researchers tested two labelling procedures (99mTc-NDRBC and 99mTc-HDRBC) for this purpose. No significant advantage was noted from the more complex 99mTc-HDRBC labelling procedure.

Research Background

• The researchers hypothesized that scintigraphic imaging could identify and quantify exercise-induced pulmonary haemorrhage (EIPH), a condition where horses bleed from the lungs during strenuous exercises.
• This study involved an imaging technique called scintigraphy—where a small amount of radioactive tracer is injected, and the radiation emitted is captured and turned into an image.
• They proposed using two labeling procedures: one using non-denatured red blood cells (99mTc-NDRBC) and another using heat-treated denatured red blood cells (99mTc-HDRBC).

Research Method

• The research involved two groups of horses. Group 1 received an injection of non-denatured red blood cells at rest. In contrast, Group 2 received red blood cells that were partly denatured by heating.
• They followed the distribution of these labeled red blood cells in all the horses for an hour.
• In a separate trial, they also confirmed the feasibility of visualizing minor pulmonary bleeding via scintigraphy. For this, an endoscope was used to deposit a radioactive solution at the common site of EIPH within a live horse. The radioactivity observed in this region was compared with that in Group 1 and 2.

Research Findings

• In Group 2, the spleen took up more of the 99mTc-HDRBC, and the lung’s radioactivity was higher and reduced slower than in Group 1.
• The complex and time-consuming 99mTc-HDRBC labeling method did not offer any significant advantage over the easier 99mTc-NDRBC procedure.
• The activity level in the endoscopy trial suggested the 99mTc-NDRBC approach was more effective in detecting bleeding.
• Overall, the study verified scintigraphy’s potential utility in detecting small amounts of horse pulmonary bleeding. It also suggested that the detection of minor amounts of bleeding may be affected by the lung’s background radioactivity level.