Transmyocardial therapeutic-delivery using real-time MRI guidance

Entry, Abstracts
Jeremy Maurer, Penn

Fig.1 (a) Needle catheter showing microcoils and extended nitinol injection needle. (b) Portions of the heart segmented on cine stack (TR/TE=3.4/1.54ms, voxel=1.3x1.3x5 mm3, FA 43o) are used to build 3d model of the left, right ventricle and infarcted region. (c) 3D model overlaid into real-time MR images is used to (d) navigate the catheter to pre- defined injection targets. Catheter model is built from MR images of active tracking coils. (e) Injection of iron-oxide laden therapeutic into myocardium (yellow arrow) monitored under real-time MRI. TR/TE=2.8/1.19 ms, voxel=1.9x1.9x5mm3, FA/tracking FA =50o/15o, 1.5-4 frames/s. (f, g) Pre- and post- injection MRI confirms injection of microbeads. TR /TE = 6.8/3.25ms, FA=30o, voxel =1.0×1.0×5.0mm3.Hegde S, Shea S, Pan L, Karmakar P, Barbot J, Kirchberg K, Vadakkumpadan F, Maurer J, Cook J, Trayanova N, Solaiyappan M, Johnston P, Kraitchman D. Transmyocardial Therapuetic-Delivery Using Real-Time MRI Guidance. SCMR 16th Annual Scientific Sessions, San Francisco, CA, January 31 - February 3, 2013. Poster.

Background: Catheter-based transmyocardial injection offers a minimally invasive method to deliver therapeutics to the heart. It is typically performed under X-ray fluoroscopic guidance, which suffers from poor demarcation of myocardial boundaries and an inability to assess myocardial viability. MRI-guided intramyocardial delivery of therapeutics at 3T offers the potential for more precise targeting of these therapies with superior tissue contrast.

Our group has been actively involved with microencapsulated stem cell therapy to improve cell retention and prevent stem cell rejection. However, most microencapsulated stem cell products are too large to be administered transmyocardially. We demonstrate here intramyocardial injection of a prototype single stem cell therapeutic into the myocardium of a normal swine using real-time MR guidance and a custom active injection catheter.

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Prehydration Requirements of Working Dogs

Honorable Mention, Abstracts
Shannon Palermo, University of Pennsylvania

Prehydration Requirements of Working Dogs

Abstract:

Detection dogs work in adverse environments. In the field, dog handlers have used subcutaneous fluids and oral electrolyte solutions in addition to water to prevent dehydration; however, the efficacy of these strategies has not been studied. Our study aimed to determine the effects of 3 prehydration strategies on body weight, blood electrolytes and search performance in police canines working in hot environments.  This field study tested 3 prehydration strategies in each of 3 police detection canines using a cross over design. Each dog was randomly assigned to 10 ml/kg of water (W), subcutaneous balanced electrolyte solution (SQ), or chicken flavored oral electrolyte solution (OES) at the beginning of each work day. All dogs were offered water every thirty minutes; however, OES dogs were offered 10 ml/kg OES if they drank <3 ml/kg of water. At the beginning, middle, and end of each day, we measured body weight, serum electrolytes, lactate, and vital signs. A timed standardized search at the beginning and end of each day was conducted. Dogs in the W (n=3) and SQ (n=3) groups drank a combined mean of 5.0 ml/kg/hr, while the OES dogs (n=3) drank 18.6 ml/kg/hr. Only dogs in the OES group developed isosthenuria and gained weight. Hematocrit decreased by the end of the work day for dogs in the OES and SQ group. Regardless of the hydration strategy all dogs had a small but significant decrease in potassium, no hydration strategy resulted in a significant change in electrolyte values throughout the day. Only dogs in the OES group maintained blood bicarbonate concentrations and had significantly faster afternoon search times compared to the morning. In this study, police dogs performing light to moderate work in hot environments were able to maintain hydration. In addition to maintaining hydration, by then end of the work day dogs in the OES group had improved search times, a significantly decreased hematocrit, and were able to maintain a consistent level of bicarbonate.