In vivo evaluation of a mechanically oscillating dual-mode applicator for ultrasound imaging and thermal ablation.

Unresectable liver tumors are often treated with interstitial probes that modify tissue temperature, and efficacious treatment relies on image guidance for tissue targeting and assessment. Here, we report the in vivo evaluation of an interstitial applicator with a mechanically oscillating five-element dual-mode transducer. After thoroughly characterizing the transducer, tissue response to high-intensity ultrasound was numerically calculated to select parameters for experimentation in vivo. Using perfused porcine liver, B-mode sector images were formed before and after a 120-s therapy period, and M-mode imaging monitored the therapy axis during therapy. The time-averaged transducer surface intensity was 21 or 27 W/cm (2). Electroacoustic conversion efficiency was maximally 72 +/- 3% and impulse response length was 295 +/- 1.0 ns at -6 dB. The depth of thermal damage measured by gross histology ranged from 10 to 25 mm for 13 insertion sites. For six sites, M-mode data exhibited a reduction in gray-scale intensity that was interpreted as the temporal variation of coagulation necrosis. Contrast ratio analysis indicated that the gray-scale intensity dropped by 7.8 +/- 3.3 dB, and estimated the final lesion depth to an accuracy of 2.3 +/- 2.4 mm. This paper verified that the applicator could induce coagulation necrosis in perfused liver and demonstrated the feasibility of real-time monitoring.

Thymoglobulin induction in liver transplant recipients with a tacrolimus, mycophenolate mofetil, and steroid immunosuppressive regimen: a five-year randomized prospective study.

This randomized, comparative study assessed the long-term efficacy and tolerability of thymoglobulin (TMG) induction in 93 liver transplant patients with an initial regimen of tacrolimus (Tac), mycophenolate mofetil (MMF), and steroids. Forty-four patients were randomly allocated to the TMG+ group, and 49 patients were randomly allocated to the TMG- group. In both groups, Tac was given orally at the initial daily dose of 0.075 mg/kg twice daily, and MMF was given at the initial daily dose of 2 g/day. Steroid withdrawal was planned at 3 months after liver transplantation. The results were evaluated with respect to acute rejection incidence, patient and graft survival, graft function, and medical complications until 5 years or death for all patients. No significant differences were found between groups for the incidence of acute rejection at 5 years (11.4% versus 14.3%), 5-year patient survival (77.3% versus 87.8%), graft function, or postoperative renal function. One patient in the TMG- group underwent retransplantation. There was no difference between groups with respect to the incidence of medical complications, excepted for a higher rate of leukopenia in the TMG+ group, during the 5-year follow-up. In conclusion, the results of this prospective randomized study suggest that the addition of TMG to a triple immunosuppressive regimen (Tac, MMF, and steroids) did not modify the incidence of acute rejection episodes or long-term survival and was responsible for increased leukopenia rates.

Back-table reconstruction of the donor replaced right hepatic artery prior to liver transplantation: what is the real impact on arterial complications?

BACKGROUND/AIMS: The aim of this study was to analyze the technique of reconstruction, prior to liver transplantation, of donor replaced right hepatic arteries and to study its impact on graft outcome. METHODOLOGY: Two groups of liver grafts were retrospectively examined. The first group (group 1) did not require any arterial reconstruction prior to liver transplantation (n=507). The second one (group 2) included grafts with right replaced hepatic arteries which required reconstruction (n=75). Patients' data were analyzed to evaluate the effect of the arterial reconstruction on the incidence of posttransplant mortality, arterial and biliary complications on one hand and patient and graft survivals on the other. We also made a comprehensive literature search to analyze the different approaches described to reconstruct such variation. RESULTS: The two groups showed no statistical sig nificant difference for early posttransplant mortality and arterial complications. Hepatic arterial thrombosis occurred in two cases in the group 2 (2.6%) and in four cases in group 1 (0.7%); p=0.17. Patient and graft survivals over the whole follow-up period were not significantly different between the two groups. The analysis of the literature found few publications dealing with reconstruction of right replaced hepatic arteries, though because various techniques were reported and the samples of patients were small, a preferred method could not clearly be identified. CONCLUSIONS: Graft arterial reconstruction of a right replaced hepatic artery using a safe and rigorous technique does not enhance the risk of arterial complications or graft loss and the technique using the GDA stump could be recommended for routine use.

Right-sided posttraumatic diaphragmatic rupture and delayed hepatic hernia.

The early diagnosis of posttraumatic diaphragmatic lesions is often difficult which explains the 30 to 50% of non diagnosed cases. This is due to the lack of sensitivity and specificity of the radiographic exams. Missed diaphragmatic lesions results in herniation of abdominal contents into the chest and may be revealed many years from the time of the original trauma. Symptoms such as dyspnea and chronic abdominal complaints are often observed and life-threatening complications, such as visceral strangulation or perforation, contribute to the late morbidity and mortality of the missed injury. Liver herniation is rare and few cases are described in the literature. We report two cases of delayed discovery of the diaphragmatic injury resulting in liver herniation. In one case, there was also an involvement of the duodeno-pancreas. The diagnosis was made 3 and 12 years after the original trauma, respectively, and respiratory embarrassment was the major presenting symptom. The surgical approach was different in the two patients; the first patient was managed by thoracotomy whereas the second patient was treated by laparotomy. The diaphragmatic defect was repaired and reinforced by a prosthetic mesh in the first case. It was closed only by suturing in the second patient. From these two cases, we reviewed the relevant literature and analysed the different approaches for diaphragmatic repair.

Developing an interstitial ultrasound applicator for thermal ablation in liver: results of animal experiments.

BACKGROUND: In this project, an interstitial ultrasound applicator was developed for the treatment of primary and secondary cancers of the liver. Experiments on animals were used to check the destructive capabilities of this probe within the hepatic parenchyma of the pig in vivo, with a study of the physical parameters of the ultrasound treatment. In parallel, the possibility of visualizing the lesions induced by means of ultrasound imaging was also studied. MATERIALS AND METHODS: Thirteen pigs were used in this project, which had received the prior approval of the ethics committee of Lyon Veterinary School. Ultrasound lesions were performed by varying the physical parameters of the treatment (acoustic intensity and shot time) with the aim of obtaining larger and larger areas of destruction. An operative device was developed to ensure precision in treatments. Two types of lesions were performed: elementary lesions corresponding to single shots at 40 degrees to 50 degrees rotation intervals, and cylindrical lesions obtained by a continuous rotary deployment of the probe. The effect of hepatic pedicle clamping on the size of ultrasound lesions was studied. The aspect and dimension of the lesions were analyzed by means of operative ultrasound imaging and macroscopic examination. Histological analysis showed the impact of the treatment on the hepatic parenchyma. RESULTS: This work made it possible to study the elementary ultrasound lesions produced by our probe. Seventy elementary ultrasound lesions were analyzed. Treatments could be performed on all pigs without any difficulty. There were no operative incidents. The ultrasound-induced elementary lesions showed complete necrosis, with lesion length of up to 37 mm obtained without resort to pedicle clamping; this must be considered as a radius of the final lesion obtained over a complete rotary deployment (360 degrees ), then a diameter of 7 cm of thermal ablation can theoretically be obtained. The effect of pedicle clamping was studied and showed improvement of the lesion length. Results of continuous rotary deployment of the probe were encouraging. Operative ultrasound imaging proved to be a simple tool for directing and positioning the applicator in the target zone on the one hand and which, on the other hand, enabled accurate, real-time visualization of the ultrasound lesions. On histological analysis, the ultrasound-induced necrosis was complete and well defined. CONCLUSION: This work shows that it is feasible to treat cancers of the liver using interstitial ultrasound probe. Thermal damage obtained on the hepatic parenchyma of pigs in vivo is complete and can be monitored using simple diagnostic ultrasound. The ultrasound parameters can be adapted to obtain destruction of variable size.

[Pancreatic acinar cell carcinoma in a patient with familial adenomatous polyposis]. / Carcinome pancréatique à cellules acineuses et polypose adénomateuse familiale.

The relative risk of pancreatic cancer has been shown to be about 4 times that of the general population in familial adenomatous polyposis patients, but its frequency remains low, and the histological nature of these pancreatic tumors has been rarely reported. We describe the case of a 65-year-old patient, with a history of familial adenomatous polyposis coli, who developed advanced duodenal polyposis and a synchronous 25 mm tumor of the pancreatic isthmus. After total pancreatectomy and antrectomy, histological examination revealed an acinar cell carcinoma and duodenal adenomas with low and high-grade dysplasia, but no cancer. To our knowledge, this is the first description of the association of familial adenomatous polyposis with acinar cell carcinoma of the pancreas.