Munehiro Maeda

Transarterial Embolization for Large Hepatocellular Carcinoma with Use of Superabsorbent Polymer Microspheres: Initial Experience

The authors report the initial experience with transarterial embolization of large hepatocellular carcinoma (HCC) with use of superabsorbent polymer microsphere (SAP-MS) particles. Six patients with nine HCCs (mean diameter, 8.2 cm) underwent 10 embolization procedures. Two patients underwent surgery later. In follow-up, tumor necrosis, postembolization syndrome, and laboratory data were assessed. Complete necrosis in three nodules, nearly complete necrosis in three nodules, and partial necrosis in three nodules were observed. Histologically, SAP-MS occluded intratumoral vessels tightly without ischemic damage of normal hepatic tissue. Postprocedural pain was minimal. No deterioration of liver function occurred. Our initial experience suggests that embolization with use of SAP-MS leads to extensive tumor necrosis of large nodular HCC, sparing use of chemotherapeutic agents.

Comparison of High Resolution Ct Findings of Sarcoidosis, Lymphoma, and Lymphangitic Carcinoma: Is There Any Difference of Involved Interstitium?

PURPOSE The purpose of this study was to determine distinguishing features of three diseases that are distributed along the lymphatics. METHOD CT scans of 40 patients with lymphangitic carcinomatosis, 41 with sarcoidosis, and 44 with malignant lymphoma were retrospectively reviewed. We evaluated the degree of involvement of the interlobular septa, bronchovascular structures, subpleural interstitium, and other CT findings. RESULTS The number of thickened interlobular septa and the extent of involvement of the subpleural interstitium in lymphangitic carcinomatosis were higher than those in sarcoidosis and malignant lymphoma (p<0.0001). Nodules of >1 cm in diameter were more often seen in malignant lymphoma (41.0%) than in the other two diseases (p < 0.001). Bilateral distribution was more common in sarcoidosis (100%) than in the others (p<0.001). CONCLUSION The major difference among lymphangitic carcinomatosis, sarcoidosis, and malignant lymphoma is the greater involvement of the interlobular septa and subpleural interstitium in lymphangitic carcinomatosis than in either sarcoidosis or malignant lymphoma.

Aortic stent-grafting with transrenal fixation : use of newly designed spiral Z-stent endograft

PURPOSE To evaluate the feasibility and efficacy of a newly designed stent-graft placed across the renal arteries for exclusion of abdominal aortic aneurysms (AAAs) with short or tortuous proximal necks. METHODS Among a group of AAA patients treated with endovascular grafting, 5 had tortuous proximal necks and 13 had necks <20 mm (mean 13 mm). In these 18 cases, a 2- to 3-cm uncovered segment of the stent-graft was placed transrenally using a catheter inserted into the renal artery as a guide for graft margin positioning. A newly designed stent-graft was constructed from a custom-made spiral Z-stent covered with a thin-walled Dacron material; the endografts were deployed through 16-F (aortoaortic model) or 18-F sheaths (bifurcated devices). Renal function was assessed by preoperative and postoperative measurement of urea nitrogen and creatinine. Aneurysm exclusion and renal artery patency were evaluated during follow-up using spiral computed tomography and angiography. RESULTS The stent-grafts were correctly placed at the intended site in all 18 patients. Renal function was not affected except transiently in 1 patient who developed bilateral renal artery stenoses 24 hours after the procedure; Palmaz stents were deployed in each renal artery to reestablish satisfactory blood flow. Of the 33 renal arteries crossed by the bare stent-graft segment, all were patent over a mean 14-month follow-up (range 7-24), including the patient with Palmaz stents implanted for postprocedural renal stenosis. Complete aneurysm exclusion was maintained in 15 (83%) of 18 patients; proximal leaks persisted in 3 patients, including 2 with severely angled proximal necks. CONCLUSIONS Transrenal placement of the uncovered leading edge of custom-made spiral Z-stent-based endografts appears feasible and clinically effective in the treatment of AAAs with short or tortuous proximal necks.

Effect of antithrombotic agents on the patency of PTFE-Covered stents in the inferior vena cava: An experimental study

AbstractPurpose: To evaluate the efficacy of antithrombotic agents in the prevention of stenosis of polytetrafluororethylene (PTFE)-covered stents in the venous system. Methods: Spiral Z stents covered with PTFE (PTFE-covered stents) were placed in the inferior vena cava (IVC) of 34 dogs. Nineteen dogs, used as a control group, were sacrificed at 2, 4, and 12 weeks. Fifteen dogs, previously given antithrombotic agents [cilostazol (n=5), warfarin potassium (n=5), cilostazol plus warfarin potassium (n=5)] were sacrificed at 4 weeks, and then examined angiographically and histopathologically. The effect of the antithrombotic agents was compared between groups. Results: The patency rate of the antithrombotic agent group was 93% (14/15), which was higher than the control group rate of 63% (12/19). The mean stenosis rate of the patent stent at both ends and at the midportion was lower at 4 weeks in the antithrombotic agent group than in the control group. In particular, the mean stenosis rate in the cilostazol plus warfarin potassium group was significantly lower than the control group (Tukey’s test, p < 0.05). The mean neointimal thickness of the patent stent at both ends and at the midportion was thinner at 4 weeks in the antithrombotic agent group than in the control group. In particular, the thickness of the neointima in the cilostazol plus warfarin potassium group was significantly decreased when compared with the control group (Tukey’s test p < 0.05). At 4 weeks, endothelialization in the antithrombotic agent group tended to be almost identical to that in the control group. Conclusion: The present study suggests that administration of an antithrombotic agent is an effective way of preventing the stenosis induced by a neointimal thickening of PTFE-covered stents in the venous system.

Percutaneous Modular Stent-Grafts in the Treatment of Abdominal Aortic Aneurysms

Purpose: To describe a newly designed bifurcated modular stent-graft and assess the feasibility and safety of its use in the treatment of abdominal aortic aneurysms (AAA). Methods: Thirteen patients (10 men; mean age 61.2±16 years, range 57–78) with AAAs underwent treatment with a bifurcated stent-graft consisting of 4 components: an unsupported bifurcated stent-graft, an inner bare stent, and 2 stent-grafts. The system was placed sequentially through a percutaneously introduced 12-F sheath; the preloaded bifurcated main body of the stent-graft was deployed first, followed by the inner bare stent and individual stent-graft limbs through separate 10-F sheaths. Spiral computed tomography (CT) was performed before treatment and at 1 week, 3 months, and then at 6-month intervals. Results: The stent-grafts were successfully deployed in all patients, although 3 types of procedure-related adverse events occurred: left limb kinking in 1, postimplantation syndrome (fever, leukocytosis, and decreased platelet count) in 5, and a small access site arteriovenous fistula in 1. Postprocedural angiography and 1-week follow-up CT scanning did not identify any endoleaks. At a mean 9.2±4.6-month follow-up, all devices were intact, with complete exclusion of the aneurysms and no endoleaks. Conclusions: This newly designed bifurcated modular stent-graft appears to be effective for percutaneous AAA repair; further investigation is warranted.

Endovascular stent graft placement for patients with aortic aneurysm and end-organ dysfunction.

Endovascular stent grafts (ESGs) for the treatment of aortic aneurysm is becoming popular because it is less invasiveness for the patient. This new modality seems to be especially useful for treating high risk patients, such as those with end-organ dysfunction. In this study we retrospectively analyzed the results of ESG placement for patients with renal or hepatic dysfunction. From January 1996 to December 1997, six patients with end-organ dysfunction (two with descending thoracic aneurysm and four with abdominal aneurysm) underwent ESG placement. Five of these patients had renal dysfunction, with serum creatinine levels of 2.0 mg/dl or greater, and the remaining patient had hepatic dysfunction with a prothrombin time less than 60%. One of the patients also had severe atherosclerotic disease with a history of multiple brain infarctions. All the patients received custom made endovascular spiral Z stents covered with a woven Dacron (DuPont Co., Wilmington, DE) graft, which was delivered via a femoral artery under local anesthesia. None of the patients showed significant changes in renal or hepatic function after the procedure. None of the five patients with renal dysfunction needed hemodialysis after ESG placement, although the mean preoperative level of serum creatinine and blood urea nitrogen was 3.4 mg/dl and 42.0 mg/ dl, respectively. All the patients left the recovery room on postoperative day 1. These results indicated that endovascular stent graft placement is extremely useful in the treatment of aortic aneurysm patients with end-organ dysfunction.

Time study of computer aided diagnosis—a preliminary results on temporal subtraction

Abstract In this paper, we present the results of time study of CAD (Computer-Aided Diagnosis) on temporal subtraction for ground-glass shadow on chest radiographs. Our results showed that the average reading time with the CAD system was significantly longer than without employing the CAD system. However, diagnostic accuracy with temporal subtraction images was slightly improved than without temporal subtraction (with; Az=0.96, without; Az=0.95). Consequently, we could interpret that the radiologists performance was enhanced by CAD on temporal subtraction, even with longer reading time.