PubMed · 6833776
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F E Rabe, G J Becker. 1983. Digital vascular imaging.. https://pubmed.ncbi.nlm.nih.gov/6833776/
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OBJECTIVES: We sought to evaluate the efficacy and tissue reaction of a new miniature interventional device for occlusion of large patent ductus arteriosus (PDA) in a neonatal lamb model. BACKGROUND: A variety of devices are used to close PDAs by interventional measures. Spring coils found to have a high cumulative occlusion rate have thus far been limited to smaller PDAs because of the physical limitation of grip forces. METHODS: Memory-shaped double-cone stainless steel coils with enhanced stiffness of the outer rings by a double-helix configuration were mounted on a titanium/nickel core wire. A snap-in mechanism attaches the coil to the delivery wire, allowing intravascular coil retrieval and repositioning. The system was placed through a 4F or 5F Teflon catheter. A chronic lamb model (n = 8) of PDA (>5 mm) was used in which ductus patency was secured by a protocol of repetitive angioplasty procedures. The animals were killed after 1 to 181 days, and the ductal region was examined by inspection as well as by light and electron microscopy. RESULTS: Placement of the coils within the PDA was possible in all lambs. Before final detachment, the coils were retrieved or repositioned, or both, up to 12 times. In all but one animal the ductus was closed within 6 days after the procedure. The coils caused no infections or aortic and pulmonary artery obstruction. Histologic and electron microscopic studies revealed endothelial coverage of the implants but no foreign body reaction or local or systemic inflammation or erosion of the implant. CONCLUSIONS: The device effectively closed large PDAs in our model and may overcome the previous limitations of coils. Clinical trials are indicated.
The usefulness of two-phase helical computed tomography (CT) of the liver was evaluated in clinical cases. First, an optimal scanning protocol was determined using time-attenuation analysis. Monophasic dynamic CT was performed with 100 ml of contrast media (iodine 300 mg/ml) injected either at 3 ml/s or at 2 ml/s. Aortic, hepatic and portal time-attenuation curves were made for each protocol. The results showed that these two different injection protocols produce equivalent enhancements and that the injection rate of 2 ml/s is satisfactorily applicable to clinical cases. The first scanning (arterial phase) must be started 40-45 s after the beginning of the injection of contrast media and the second scanning (delayed phase) 80-120 s after the beginning of injection. Using these CT protocols, 327 cases were examined. In this study 83 hepatic lesions (hepatocellular carcinoma : HCC, n = 29; suspected HCC, n = 30; hemangioma, n = 24) were evaluated. There were 15 HCCs smaller than 30 mm in diameter (71.4%) detected by either arterial phase or delayed phase alone. This result indicates that two-phase helical hepatic CT is very useful in the detection of small HCC. Particularly, four of 5 HCCs of less than 10 mm in size (80%) showed a hyperattenuation area in the arterial phase alone. HCCs which have sufficient vascularity were also easily demonstrated. However, this two-phase helical hepatic CT could not demonstrate 11 lesions (13.3%) with almost normal blood supply. In such cases the complementary role of ultrasound (US) seems to be important. Hence as a screening of hepatic mass lesions both CT and US are necessary. Most HCC could be differentiated from hemangioma by an enhancement pattern using this protocol. But the small liver lesions of less than 15 mm in size with homogeneous hyperattenuation in the arterial phase and isoattenuation in the delayed phase included HCC, hemangioma and metastatic tumors.
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