Diagnosing Hepatobiliary disease during myocardial perfusion imaging (MPI), using Tc99m methoxy isobutyl isonitrile (MIBI) as an adjunct benefit

Objectives: Tc99m labeled Hepatic Imino Diacetic Acid (HIDA) derivatives have been used to evaluate gallbladder (GB) disease, which is one of the most common digestive system illnesses around the world. Similarly, Tc99m Methoxy Isbutyl Isonitrile (MIBI) has been used for myocardial perfusion imaging MPI) for the detection of ischemia in patients with known or suspected coronary artery disease (CAD). Then it would not be unusual if a request to perform both studies is ordered for the same patient at the same time. This study was undertaken to investigate the feasibility of effectively evaluating cystic duct patency, during routine visual analysis of the raw MPI and/or the 3-d reconstructed data. Methods: We retrospectively reviewed 2950 consecutive MPI studies collected over a 2 year period, of which 80% were pharmacological and 20% were treadmill data. 91 of these patients (3%) also had HIDA studies performed. GB visualization during either Rest or Stress portion of the MIBI study was indicative of cystic duct patency. These results were then compared to those obtained by the HIDA studies. Results: 10 patients, 5 males and 5 females, had the HIDA and MIBI studies 4 days apart. Age 60.2 +/- 18.6 yrs and a BMI 31.9 +/- 11.4, both studies agreed 100% with the diagnosis of cystic duct patency. 16 additional patients, 5 males and 11 females, had both studies within 3 weeks of each other. Age 59.6 +/- 14.3 yrs and a BMI 31.7 +/- 11.2, both studies had an agreement of 86% with cystic duct patency. The last group of 65 patients, 42 males and 23 females, had both studies 1 to 3 months apart. Age 56.3 +/- 12.9 yrs and a BMI 34 +/- 12, both studies had an agreement of 80% with cystic duct patency. Conclusion: In summary, the initial results of this study, although in a small number of patients (n=10), indicate that MPI studies with Tc99m MIBI are useful in effectively detecting a patent cystic duct. The results showed 100 % agreement with those obtained with Tc99m HIDA for hepatobiliary imaging. This investigation should prove to be a useful addition for GB evaluation, especially in the acute setting.