Noninvasive techniques to evaluate the vaso-occlusive manifestations of sickle cell disease

Although the pathophysiologic manifestations of sickle cell disease have been assumed to result from microvascular occlusion consequent to in situ sickling of erythrocytes, actual blood vessel obstruction have been rarely demonstrated in vivo. Recent observations utilizing sophisticated biophysical techniques to study the intracellular hemoglobin S polymerization process has led to major revisions in this previously held pathophysiologic paradigm, but in vivo correlations are still lacking. With the development of new noninvasive imaging and para-imaging methods, it is now technically possible and feasible to characterize both regional organ perfusion and tissue biochemistry in quantitative terms. In addition, these modalities promise to clarify pathogenesis of the disease through definition of the events responsible for the progression from tissue ischemia and infarction through the resolution phase. Since these noninvasive techniques are amenable to sequential applications, they should facilitate objective evaluations of clinical trials of therapeutic agents designed to prevent or delay the vaso-occlusive manifestations of sickle cell disease.