Ultrasonic characterization of myocardial photocoagulation lesion size in vivo during Nd:YAG laser irradiation.
Endocardial coagulation lesions were created using transcatheter continuous-wave Nd:YAG laser irradiation. Ultrasound monitoring of thermal lesion dimensions was performed using 7.5-MHz and 10-MHz transducers directly from the epicardial surface in short-axis configuration (group A) or through the chest wall (group B). A total of 33 lesions were created in 10 dogs at energy levels ranging from 300 J to 1000 J. Mean histological lesion width (HW) compared with ultrasonically determined mean width (UW) showed that the differences (mean +/- standard deviation) in group A (UW - HW) was = 1.14 +/- 0.8 mm, which was not statistically significantly different from zero. In group B, (UW - HW) = 2.04 mm +/- 0.7 mm (p < .05), which was statistically significantly different from zero. Mean histological depth (HD) differentially related to ultrasound mean depth (UD) for group A and B combined showed (UD - HD) = -0.19 mm +/- 0.46 mm, not statistically significantly different from zero. The frequency distribution for width in group A showed magnitude of UW-HW > 3 mm in 32% of cases. In group B magnitude of UW-HW > 3 mm in 15%, whereas ultrasound width was larger than histology in 75% of the cases. For depth, magnitude of UD-HD > 3 mm in 15% of cases. With further refinement of the technique, ultrasonic tissue characterization may become a useful adjunct to monitoring lesion dimensions during transcatheter laser photocoagulation.
Splinter
R
R
Laser and Applied Technologies Laboratory, Carolinas Medical Center, Charlotte, North Carolina 28203.
Tuntelder
J R
JR
Chuang
C H
CH
Thompson
M
M
Littmann
L
L
Svenson
R H
RH
Dezern
K R
KR
Tatsis
G P
GP
D000818:Animals; D001831:Body Temperature; D006328:Cardiac Catheterization; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology; D004285:Dogs; D004452:Echocardiography; D005240:Feasibility Studies; D005260:Female; D006321:Heart / Q000528:radiation effects; D017075:Laser Coagulation / Q000009:adverse effects*; D008297:Male; D008991:Monitoring, Physiologic; D009206:Myocardium / Q000473:pathology*