Myocardial Viability

Metalloporphyrins and Functional Analogues as MRI Contrast Agents

“…Except for slight discoloration that faded considerably over 24 hours, during animal experiments no detectable side effects were reported with porphyrin agents at a dose range of 0.05-0.1 mmol/kg [7,[38][39][40][76][77][78][79][80][81][82][83][84][85][87][88][89][90][91][92][93][94]97,99,100]. Unfortunately, despite optimistic expectations [104], further commercial development of these chromatic porphyrin complexes has been abandoned by the industry, most likely due to predicted unsatisfactory clinical tolerance and adverse effects upon the unalterable natures of these dark pigments (Fig.…”

“…7) [7,9,11,14,38,39,104]. Even negative findings after CE with NACAs help to reliably exclude the presence of necrosis and to reaffirm tissue viability, which would also be of high significance for differential diagnoses in clinical cardiology [76,81,95]. Local high concentrations of NACAs enabled both T1 and T2 CE in reperfused MI at relevant MRI sequences, suggesting their extraordinary bifacial MR enhancing capacities [14].…”

“…In addition to intravenous doses of porphyrinNACAs at 0.05-0.1 mmol/kg for cardiac MRI to visualize acute MI with an extended imaging window over 3-48 h [7,[76][77][78][79][80][81][82][83][84][85][88][89][90][91][92][93][94], intracoronary delivery of Gadophrin-2 at a tiny dose of 0.005 mmol/kg in combination with the percutaneous transcatheter coronary angioplasty procedures could function as a diagnostic adjuvant for myocardial viability determination and therapeutic assessment after these routine cardiac interventions [9,14,76,86,95]. This approach was rated by the French specialists as one of the best cardiac imaging techniques in 2002 [96].…”

“…Unfortunately, these porphyrin-based CAs can no longer be considered as true tumor-specific markers, but their superb necrosis targetability has elicited novel and even more exciting utilities for MRI visualization of acute myocardial infarction [9,14,[76][77][78][79][80][81][82][83][84][85][86]] and brain infarction [87]. Being able to induce strong, selective and stable CE is an important criterion for consideration of tissue or disease specific MRI CAs.…”

“…With regard to the quality of CE in necrosis, the tested porphyrin CAs perfectly meet this criterion. To distinguish from other antibody or receptor mediated tissue specific CAs that feature apparently different mechanisms of targetability, we propose to nominate these metalloporphyrin compounds and later developed functional analogues of nonporphyrin species as "Necrosis-Avid Contrast Agents" or NACAs because of the exhibited extraordinary avidity to necrotic and/or infarcted tissues as their main targets [9,14,[76][77][78][79][80][81][82][83][84][85][86].…”