Lung imaging perfusion

A subsequent investigation (6 ) studied the resolution and sensitivity of Mn-52m as a quantitative measurement of the size and location of myocardial ischemia. Comparison between microsphere distributions and Mn-52m images taken at 1.5 cm levels revealed that an ischemic area down to the size of 2.5 cm with 50% of the normal myocardial perfusion can be seen in the positron images. In addition, a relative change of 10% or more of the normal perfusion in the ischemic area can also be observed. Large clinical studies with the Fe-52m/Mn-52m generator have recently been initiated at the National Heart and Lung and Institute, National Institutes of Health, Bethesda, Maryland ... 

Rubidium-82 myocardial perfusion images are used to study patients with myocardial ischemia or infarction. An example of this study is shown in Figure 8. Three patients with known myocardial infarction were imaged with Rb-82. Twenty millicuries of Rb-82 were administered in a 20 ml bolus in 20 sec. Data accumulated from 0-90 seconds post infusion show the blood pool as the radioactivity enters the right side of the heart, flows out to the lungs, and returns to the left side of the heart. Data accumulated from 90-300 seconds reflect uptake of Rb-82 in the myocardium as distributed by blood flow. These results by a non-invasive procedure correlated with the results of catheterized contrast x-ray studies (27,28). 

Tc" 6h To image skeleton and heart muscle, brain, thyroid, lungs (perfusion and ventilation), liver, spleen, kidney (structure and filtration rate),... 

Figure 14 Planar anterior and posterior images obtained following inhalation of two different-size pMDI aerosols, with the outline of the lung drawn from the anterior and posterior perfusion scans. The difference in geometry and distribution of deposited radioactivity between the anterior and posterior images reflects the proximity of that area of the lung to the gamma camera face.

Reinartz P, Schirp U, Zimny M, Sabri O, Nowak B, Schafer W, et al. Optimizing ventilation-perfusion lung scintigraphy parting with planar imaging. Nuklear-medizin 2001 40(2) 38-43. 

Earlier we described how pharmacokinetic and dynamic properties of inhaled drugs are relevant for pulmonary selectivity. The assessment of pharmacokinetic and dynamic properties is consequently relevant for drug development and clinical practice. This section reviews some of the relevant techniques for assessing such properties. The available tools range from cell culture or isolated lung perfusion models to mucociliary clearance analysis, imaging techniques, and in vivo pharmacokinetic and dynamic analysis of the inhaled drug. 

Preliminary studies explored preparation of " Ta-labeled myocardial perfusion agents (Holman et al. 1979 Layne et al. 1991) and also applications for lung and liver imaging (Neirinckx et al. 1979). High resolution and statistical quality FPRNA studies of ventricular performance were demonstrated in a group of 38 patients in comparison with the traditional Tc methods (Lacy et al. 1991). Verani et al. (1992a) demonstrated the usefulness of this... 

This approach can be used to extract further clinically relevant information from CT scans acquired at normal dose levels. For example, it is possible to identify iodine in liver or kidney tissue and to display the contrast enhancement either by colorcoding it in the CT image or by subtracting it to obtain virtual unenhanced images. This also works in lung tissue for the evaluation of pulmonary perfusion. Also, bones can be eliminated from angiography datasets by the spectral properties of calcium so that the evaluation of vessels becomes easier and faster in a maximum intensity projection. Applications without contrast material include the differentiation of kidney stones and the depiction of tendons and ligaments. 

Amundsen T, Torheim G, Waage A, Bjermer L, Steen PA, Haraldseth O. Perfusion magnetic resonance imaging of the lung characterization of pneumonia and chronic obstructive pulmonary disease. A feasibility study. J Magn Reson Imaging 2000 12 224-231. 

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