Stent-Graft Treatment of Dissecting Aneurysm in Association with Aortic Intramural Hematoma: When Should the Procedure Be Performed?

Purpose:

To report 2 cases of stent-graft implantation for localized dissecting aneurysm during the conservative treatment of aortic intramural hematoma.

Case Reports:

One patient underwent stent-graft implantation for 2 localized dissecting aneurysms about 23 months after symptom onset. Computed tomography (CT) 1 year after the procedure demonstrated aneurysm shrinkage. In the other patient, a localized dissecting aneurysm was treated about 3 months after symptom onset, even though the intramural hematoma had not resolved. CT scanning 3 months after the procedure demonstrated aneurysm shrinkage, but also revealed poor attachment of the distal stent-graft to the aortic wall due to subsequent resolution of the hematoma.

Conclusions:

Endograft implantation for treatment of localized dissecting aneurysm associated with aortic intramural hematoma should probably not be performed before the hematoma has completely resolved.

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.

Superselective urokinase infusion therapy for dorsalis pedis artery occlusion in Buerger's disease

Occlusion of the proximal left dorsalis pedis artery (DPA) in a patient with Buerger's disease was treated by continuous urokinase intraarterial infusion using a microcatheter. Recanalization of the DPA and healing of a toe ulcer were achieved. The patient remains asymptomatic during a 4-year follow-up.

Experimental TIPS with spiral Z-stents in swine with and without induced portal hypertension

PURPOSE

To assess the suitability of spiral Z-stents for transjugular intrahepatic portosystemic shunt (TIPS) and the influence of portal hypertension on shunt patency in young swine.

METHODS

TIPS were established using spiral Z-stents in 14 domestic swine. In 7 animals, the portal venous pressure was normal; in the other 7, acute portal hypertension was induced by embolization of portal vein branches. Follow-up portal venography and histologic evaluations were done from 1 hr to 12 weeks after TIPS.

RESULTS

Follow-up transhepatic portal venograms showed progressive narrowing of the shunt, most prominent in the midportion of the tract. Ingrowth of liver parenchyma between the stent wires found after 3 weeks led to progressive shunt narrowing and shunt occlusion by 12 weeks. A pseudointima grew rapidly inside the stent, peaked in thickness around 4 weeks, and decreased later. Acutely created portal hypertension rapidly returned to normal and there was no difference in TIPS patency between the two groups of animals.

CONCLUSION

Although the spiral Z-stent can be used as a device for creation of TIPS in patients with cirrhotic livers, it is associated with extensive liver ingrowth in swine that leads to rapid shunt occlusion. Portal hypertension was only transient in this model.

Optimal lipiodol volume in transcatheter arterial chemoembolotherapy for hepatocellular carcinoma: study based on lipiodol accumulation patterns and histopathologic findings

To clarify the optimal dose of Lipiodol (Andre Guerbet, Aulnay-sous-Bois, France) during Lipiodol-transcatheter arterial embolization (L-TAE) and segmental L-TAE used to treat hepatocellular carcinoma, we studied the relationship between the volume of Lipiodol used during these procedures and the necrosis rates in resected specimens, as well as the correlation with the Lipiodol accumulation pattern based on the computed tomography findings (L-CT) and the volume of Lipiodol in resected and nonresected cases after L-TAE or segmental L-TAE. The L-CT and the dose of Lipiodol injected (mL) were studied correlatively in 198 cases (28 resected cases and 170 nonresected cases; tumor size < or = 5 cm in 52 cases and > 5 cm in 118 cases) that underwent L-TAE and in 80 cases (14 resected cases and 66 nonresected cases, tumor size < or = 5 cm in 52 cases and > 5 cm in 14 cases) that underwent segmental L-TAE. The L-CT was classified into four types: type I, homogeneous accumulation (type Ia, accumulation around the tumor; type Ib, no accumulation around the tumor); type II, partial defect; type III, sporadic accumulation; and type IV, punctate or no accumulation. In the 42 resected cases (L-TAE, 28 cases; segmental L-TAE, 14 cases), type I was seen in 68% (Ib, 100%) of the L-TAE cases and 93% (Ia, 79%; Ib, 14%) of the segmental L-TAE cases. The necrosis rate of the cases with type Ib L-CT was 90% to 100%, and all type Ia cases showed complete necrosis. In the 236 nonresected cases (L-TAE, 170 cases; segmental L-TAE, 66 cases), the volume of Lipiodol injected correlated with the L-CT type. In the L-TAE cases with a tumor size < or =5 cm, the frequency of the injected Lipiodol volume (D) being greater than the tumor diameter (d) (D > or = d) was 90%, and 87% of the cases with D > or = d showed type Ib L-CT. In the group whose tumor diameter (d) was more than 5 cm, the frequency of D > or = d was 25%, and 70% of the cases of D > or = d were type Ib. The frequency of D < d was 75%, and in 13% of these cases the L-CT was type Ib and the maximum dose was approximately 10 mL. In segmental L-TAE using the same dose of Lipiodol as in L-TAE, the frequency of D > or = d was 83%, and 93% of those cases showed type I, including 85% of type Ia. There was a correlation between the L-CT type and the necrosis rate, and type I, especially Ia in segmental L-TAE, showed complete necrosis in almost all cases. In L-TAE, standards for the optimal dose of Lipiodol are thought to be as follows: D > or = d in cases with d < or = 5, and slightly D < d and 10 mL maximally in cases with d > 5. In segmental L-TAE using the same dose of Lipiodol as in L-TAE, enhancement of the therapeutic effect was seen compared with L-TAE. This is surmised to have been because of the higher Lipiodol volume with anticancer agents per unit volume of the tumor in segmental L-TAE.

[Balloon angioplasty and metallic stent]

Recently, interventional radiology (IVR) has been playing an important role as a treatment for the arterial occlusive diseases. Balloon angioplasty (PTA) is widely used for the stenotic lesions and clinical results are acceptable. However, some other procedures are frequently needed, and metallic stents (MS) are useful quite often. There are three main groups of stents: self-expanding stainless metallic stents (Z-stent, Wallstent), balloon-expandable stents (Palmaz stent, Strecker stent), and shape memory alloy stents, which are not clinically available for the iliac and femoro-popliteal arteries now in Japan except for Palmaz stent. However, it is expected that these MS will be available soon. In this paper we described the clinical utility of PTA and MS for the arterial occlusive diseases in the iliac and femoro-popliteal lesions based on our experience and past reports and also mentioned the future of IVR.

Bile duct injury as a major cause of stenosis and occlusion in transjugular intrahepatic portosystemic shunts: comparative histopathologic analysis in humans and swine

PURPOSE

A comparative histologic analysis of human and swine transjugular intrahepatic portosystemic shunts (TIPS) was performed to investigate factors limiting TIPS patency and to further develop an animal model for TIPS.

MATERIALS AND METHODS

Twenty-one human and 13 porcine shunts were evaluated by means of gross inspection, histologic evaluation, and electron microscopy.

RESULTS

Severe stenosis (> 75% narrowing) or occlusion was detected with portal venography in nine of the 21 human shunts (48%) and in 10 of 13 porcine shunts (77%). Gross or histologic evidence of a substantial biliary fistula was observed in seven of nine porcine shunts and in seven of eight human shunts with severe parenchymal tract stenosis or occlusion. No evidence of substantial bile duct injury was identified in the 13 human shunts or two swine shunts with patent, nonstenotic parenchymal tracts (P < .01, Fisher exact). Histologic findings in porcine shunts mimicked human tissue responses, including a metaplastic proliferation of bile duct epithelium at sites of bile duct transection.

CONCLUSION

Bile duct transection and bile leak are significantly associated with TIPS parenchymal tract abnormalities in patients and swine. TIPS in swine created with the Wallstent faithfully reproduce gross morphologic and histologic changes observed in patients.

[Chemoembolization therapy in small hepatocellular carcinoma]

As chemoembolotherapy (TAE) for relatively small hepatocellular carcinoma (HCC) including small HCC of less than 2 cm in diameter, which is restricted to a sub-subsegment, subsegment or segment of the liver, segmental Lp-TAE using Lipiodol (Lp) mixed with an anticancer agent, which includes subsegmental and sub-sub-segmental therapy, not restricted to the tumor-bearing segment, is expected to move to the forefront of HCC treatments and also causes fewer complications and less strain to the patient. Of the 15 cases that underwent surgery following segmental Lp-TAE, complete necrosis was found histopathologically in more than 80% of the main tumor, satellite nodules in the embolized region and areas of capsular invasion. Its therapeutic efficacy for 51 cases with tumors smaller than 3 cm was comparable to that of surgery.

Acute aortic dissection with intramural hematoma: possibility of transition to classic dissection or aneurysm

Acute aortic dissection with intramural hematoma has been believed to have a good prognosis, but we have encountered the transition of this entity to a classic dissection or aneurysm. We report the serial computed tomography (CT) features in 27 cases of acute aortic dissection with intramural hematoma. Eleven patients (40.7%) developed a classic dissection or aneurysm during follow-up. Four patients (14.8%) showed transition to a classic dissection without resolution of the intramural hematoma; each had a dilated ascending aorta measuring > 5 cm in diameter on the initial CT. One case (3.7%) developed an enlarging aneurysm without resolution of the intramural hematoma. In 19 cases (70.4%), the hematoma resolved; among these 19, the aortic diameter was significantly larger (p < 0.01) than those in a normal control group. Two of these 19 later developed an aneurysm, and four developed a classic dissection. This entity often (40.7%; 11 of 27) required surgical intervention or periodic follow-up CT examinations, particularly with a dilated ascending aorta of > 5 cm in diameter.

Pharmacologic treatment of intimal hyperplasia after metallic stent placement in the peripheral arteries. An experimental study

RATIONALE AND OBJECTIVES

To evaluate the efficacy of oral administration of cilostazol, an antithrombotic agent, for the prevention of thrombotic occlusion and intimal hyperplasia after stenting.

METHODS

Single-bodied Z-stents were placed in the iliac arteries of 23 dogs. Before stenting, an embolizing coil was introduced into the right femoral artery to reduce blood flow in the right iliac artery. Eleven dogs were given cilostazol orally, and the other 12 were unmedicated as a control group. The dogs were killed at 4, 13, and 24 weeks.

RESULTS

Intraluminal narrowing due to thrombus was observed in 25% of dogs in the control group but in none of the dogs in the cilostazol group. The thickness of the neointima was significantly thinner in the cilostazol group than in the control group at 24 weeks on the noncoiled side (P < 0.05), and at 4 and 24 weeks on the coiled side (P < 0.01).

CONCLUSIONS

These results suggest that oral administration of cilostazol is an effective method of preventing thrombotic occlusion and intimal hyperplasia after stenting.

Improved transjugular intrahepatic portosystemic shunt patency with PTFE-covered stent-grafts: experimental results in swine

PURPOSE

To evaluate the ability of stent-grafts made with polytetrafluoroethylene (PTFE) graft material to improve transjugular intrahepatic portosystemic shunt (TIPS) patency.

MATERIALS AND METHODS

TIPS were created in 13 swine by using PTFE-covered stent-grafts. Uncovered TIPS were placed in 13 other swine. Twenty-one of 26 animals were followed up with portal venography for 3 months or until the shunt became severely stenotic. Five animals without severe stenosis were sacrificed before 3 months because of illness.

RESULTS

At 4 weeks after TIPS placement, nine of 13 stent-graft TIPS were patent (< 50% diameter narrowing) compared with only one patent stent in 13 uncovered TIPS. Six of 13 stent-graft TIPS remained patent until the animals were sacrificed. In 11 of 12 uncovered TIPS, stenosis was most prominent in the parenchymal tract. In five of seven stent-graft TIPS, stenosis was most prominent in the hepatic vein above the end of the graft material. Bile leaks were discovered in six occluded uncovered TIPS and in two of the stent-graft TIPS.

CONCLUSION

PTFE-covered stent-grafts significantly improved TIPS patency in swine (P < .01). However, stenosis in the hepatic vein led to late shunt malfunction in selected cases.

Crossover approach with a J-shaped sheath for angioplasty of iliofemoral artery stenoses and occlusions

Thirty patients with atherosclerotic stenoses or occlusions of iliofemoral arteries were treated from the contralateral approach using a newly designed J-shaped sheath. Seven patients with stenoses and one with an occlusion were successfully dilated with balloon angioplasty. Twenty-two patients with occlusions were treated with urokinase infusion, 16 of whom received coaxial infusion with the J-shaped sheath and catheter. Complete thrombolysis was achieved in 18 patients. The treatment success rate was 100% in the stenotic group and 83% in the occlusion group. Initially, J-shaped sheaths were useful for treatment of iliofemoral artery lesions from the contralateral femoral artery.

Combined transjugular intrahepatic portosystemic shunt and segmental Lipiodol hepatic artery embolization for the treatment of esophagogastric varices and hepatocellular carcinoma in patients with cirrhosis: preliminary report

PURPOSE

To evaluate the feasibility of combining placement of a transjugular intrahepatic portosystemic shunt (TIPS) and transcatheter hepatic segmental artery chemoembolization with Lipiodol (Seg-Lp-TAE) in patients with cirrhosis, esophagogastric varices, and hepatocellular carcinoma (HCC).

METHODS

Five patients with bleeding or large, high-flow esophagogastric varices and HCC were treated by TIPS and Seg-Lp-TAE.

RESULTS

The mean portosystemic pressure gradient decreased from 20.8 cm H2O to 7.8 cm H2O after TIPS. The direct portogram and endoscopic examination revealed reduction of varices. At 6 months, one shunt had functionally occluded and could not be reopened; the other TIPS remained functional. Follow-up CT and the changes of alpha fetoprotein indicated effective therapy of Seg-Lp-TAE for HCC. Four patients are in stabile clinical condition at 9, 6, 1, and 1 months after the combined therapy; one died after 14 months due to decompensated liver cirrhosis.

CONCLUSION

The combined therapy of TIPS and Seg-Lp-TAE will become a new interventional approach for patients with HCC and esophagogastric varices.

[Renal ablation by transcatheter renal arterial embolization in the treatment of benign renal disease]

Renal ablation by transcatheter renal arterial embolization (TAE) was performed in 10 patients with benign renal disease (hydronephrosis n = 6; renovascular hypertension n = 3; nephrotic syndrome n = 1). Each affected kidney had little or no renal function. Six patients with hydronephrosis were treated with TAE using absolute ethanol alone in three patients and the combination of absolute ethanol and gelatin sponge in the other three. Each patient was followed by sclerotherapy of the pelvocalyceal system via nephrostomy using absolute ethanol. In four of the six patients, the embolized kidney had no urine, and there was very little urine in the remaining two. The size of the embolized kidney was markedly decreased on CT. The three patients with renovascular hypertension were pre-studied by selective and renal vein sampling for PRA, and the kidney excreting higher renin was embolized by TAE with absolute ethanol. Blood pressure has become manageable without antihypertensive drug in two patients and with a reduced amount of drug in one. The patient with nephrotic syndrome had end stage renal failure and showed significant protein excretion. To prevent further protein loss, both kidneys were embolized with stainless steel coils. Urine output was significantly decreased, and consequently, hypoalbuminemia improved. All patients tolerated the procedure well, and there were no significant complications. Renal ablation by TAE may be an alternative to surgical treatment in selected patients with benign renal disease, particularly in patients with contraindications to surgery and in the elderly. Absolute ethanol and gelatin sponge seem safe and effective for TAE in patients with hydronephrosis and renovascular hypertension. For hydronephrosis, we recommend combining TAE with sclerotherapy of the pelvocalyceal system via nephrostomy using absolute ethanol. Though we successfully applied steel coil for the patient with nephrotic syndrome, absolute ethanol may be equally effective.

Segmental transarterial chemoembolization with Lipiodol mixed with anticancer drugs for nonresectable hepatocellular carcinoma: follow-up CT and therapeutic results

We developed segmental Lp-TAE, which is transcatheter hepatic sub-subsegmental, subsegmental, or segmental chemoembolization using Lipiodol introduced into the tumor-bearing hepatic sub-subsegment, subsegment, or segment as the target area. A total of 98 patients with nonresectable hepatocellular carcinoma (HCC) undergoing segmental Lp-TAE (Seg-Lp-TAE) were studied, and the relationship between the CT pattern observed after Seg-Lp-TAE (Seg-Lp-CT) and the therapeutic results obtained in those patients was evaluated. Seg-Lp-CT was classified into four types (type I, homogeneous; type II, defective; type III, inhomogeneous; and type IV, only slight accumulation, if any) according to the Lipiodol accumulation pattern observed after Seg-Lp-TAE. The cumulative nonrecurrence rates of type I were higher than those of types II-IV. The cumulative survival rates of type Ia, in which Lp accumulation is also seen around the main tumor, were the highest (93.8% at 1 year, 85.9% at 2 years, 85.9% at 3 years, and 57.3% at 4 years). The cumulative survival rates achieved with Seg-Lp-TAE were 89.2% at 1 year, 69.4% at 2 years, 58.9% at 3 years, 44.0% at 4 years, and 30.2% at 5 years, which were higher than those achieved with conventional Lp-TAE. Seg-Lp-TAE is very useful in the treatment of HCC limited to one sub-subsegment, subsegment, or segment, and it is important to choose sub-subsegmental, subsegmental, or segmental Lp-TAE on the basis of the size and site of the tumor as well as the type and the number of feeding arteries.

Segmental transcatheter hepatic artery chemoembolization with iodized oil for hepatocellular carcinoma: antitumor effect and influence on normal tissue

PURPOSE

Segmental transcatheter arterial embolization (TAE) with use of iodized oil mixed with an anticancer drug, followed by injection of gelatin sponge particles, was undertaken to evaluate its antitumor effect and its influence on normal tissue in patients with hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Histologic findings in 12 patients who underwent hepatectomy after segmental TAE were compared with findings on plain radiographs and computed tomographic (CT) scans. Visualization of the portal veins contiguous to the tumor on radiographs and the pattern of iodized oil accumulation in the tumor and vicinity on CT scans after TAE were assessed.

RESULTS

Complete necrosis of the tumor was achieved in 10 cases (83%), while complete necrosis of daughter nodules and capsular invasion was observed histologically in eight of these 10 patients (80%). The degree of tumor necrosis correlated with the pattern of iodized oil accumulation in and near the tumor. Partial necrosis of normal tissue near the tumor correlated with accumulation of iodized oil.

CONCLUSION

Segmental TAE may be an excellent therapeutic method for treatment of HCC that is localized in one or a few segmental or subsegmental regions.

Segmental embolotherapy for hepatic cancer: keys to success

Transcatheter chemoembolization using Lipiodol (Lp) mixed with chemotherapeutic agents followed by Gelfoam particle injection only to the tumor-bearing hepatic segment (segmental Lp transcatheter hepatic artery embolization) (TAE) was applied to more than 100 patients with hepatocellular carcinoma and metastatic liver cancer. For segmental Lp-TAE, knowledge of the variations of intrahepatic arterial anatomy is important. Furthermore, the catheters and guidewires, volume of Lp, kinds and dose of chemotherapy, preparation of the mixture of Lp and chemotherapy (Lp-emulsion), method of injection of Lp-emulsion and Gelfoam particles, as well as the follow-up computed tomography examination are key items to the success of the procedure and are reviewed.

[Study on the evaluation of recurrence of HCC and the effect after transcatheter hepatic arterial embolization--fluctuations in AFP values]

To determine the usefulness of alpha-fetoprotein (AFP) in determining recurrence of HCC after interventional angiography (IVA) and to define the relation between AFP and the imaging diagnosis of HCC recurrence, changes in AFP values in 160 patients with hepatocellular carcinoma who were treated by IVA > or = two times were classified into four patterns: A: the AFP value was decreased after the first IVA, increased at recurrence and decreased again after the second IVA; B: the AFP value was unchanged after the first IVA, but increased at recurrence and decreased after the second IVA; C: the AFP value was decreased after the first IVA, but was not increased at recurrence; D: the AFP value showed no change. The frequency of each AFP pattern and the diagnosis of recurrence by AFP were determined. The relation between tumor type and AFP was defined. Pattern A was the most frequently detected. In 62.6%, AFP was increased at recurrence (A and B), and there was a positive correlation between changes in the AFP value and the findings of imaging diagnosis. In another 37.5%, AFP was not increased at recurrence (C and D), and therefore, the diagnosis of HCC recurrence by imaging methods was very important.

[Usefulness of segmental Lp-TAE using lipiodol mixed with anticancer agent for inoperable hepatocellular carcinoma]

To determine the effect of appraising subsegmental or segmental transarterial embolization with Lipiodol mixed with anticancer drugs followed by gelatin particles (Segmental Lp-TAE) on inoperable hepatocellular carcinoma, we examined CT patterns and therapeutic results in 57 patients after Segmental Lp-TAE. Fifty-six tumors including 47 tumors less than 5 cm in size were the nodular type and 1 tumor was the massive type. The mean tumor size was 3.6 cm and the mean amount of Lipiodol was 4.4 ml. Portal veins in the embolized segment were highly visualized by injected Lipiodol on plain film immediately after Segmental Lp-TAE. On the follow-up CT, the size of the tumor with dense Lipiodol accumulation were reduced in all cases, and atrophy of the embolized segment was recognized. Forty-four of the 57 patients are alive, with the longest surviving patient still alive at 4 years and 5 months. Seventeen patients have survived for more than 2 years (direct crude survival rate: 65.0%), with the cumulative survival rates 93.2% at 1 year, 71.6% at 2 years. No recurrence was recognized in 33 of the 41 patients (80.0%) that were followed up for more than 1 year after Segmental Lp-TAE is a useful therapeutic method for hepatocellular carcinoma.

Iliac artery stenosis and occlusion: preliminary results of treatment with Gianturco expandable metallic stents

Ten patients with atherosclerotic stenosis or occlusion of the iliac artery were treated with Gianturco expandable metallic stents. In the five cases of stenosis, only balloon dilation was performed prior to placement of stents. The five patients with occluded arteries were given intraarterial infusions of urokinase before balloon dilation and stent placement. Clinical symptoms improved in all patients, and no technical failures or complications occurred. Doppler ankle-brachial index studies were performed in nine cases, and in all nine cases the indexes improved after stent placement. During follow-up of 2-18 months (mean, 10.3 months), all arteries remained patent. Follow-up angiograms showed slight intimal thickening and no restenosis. Long-term follow-up and more clinical experience will be necessary to evaluate the efficacy of this stent. However, preliminary results suggest that the Gianturco expandable metallic stent is of value in the treatment of arterial occlusive disease.

Transcatheter hepatic segmental arterial embolization using lipiodol mixed with an anticancer drug and Gelfoam particles for hepatocellular carcinoma

Transcatheter hepatic segmental arterial chemoembolization using Lipiodol mixed with an anticancer drug followed by the injection of Gelfoam particles, introduced into the tumor-bearing hepatic segment as the target area (segmental Lipiodol-TAE), was carried out in 54 patients with hepatocellular carcinoma (HCC), 7 of whom were later resected. In 5 of the resected 7 cases, complete necrosis was histologically verified. No death due to HCC was encountered in 47 nonoperated cases, and better therapeutic results were obtained with segmental Lipiodol-TAE. It was concluded that this technique does not adversely affect normal tissues, and it does reinforce the effect of TAE.

[The analysis of superselective catheterization technique; transcatheter segmental arterial embolization using lipiodol for hepatocellular carcinoma]

The practical limitations of catheters used for infusion were studied by their types in 47 patients with hepatocellular carcinoma who were treated by Segmental Lp-TAE. For catheterization into the arterial branches of S5 and S8, a coaxial infusion catheter was helpful. However, a coaxial infusion catheter was seldom used for catheterization into the arterial branches of S6 and S7. For infusion into vessels having diameters of less than 1.9 mm at the tip end of the catheter, positive use of a coaxial infusion catheter is strongly recommendable. A Tracker-18 catheter was especially helpful for catheterization into the vessels of S5.

[Evaluation of a biliary endoprosthesis using expandable metallic stents]

A biliary endoprosthesis constructed of Gianturco self-expanding metallic stents was placed in twenty-nine patients with obstructive jaundice, 27 malignant and 2 benign. All endoprostheses were placed successfully. External drainage catheters were removed in twenty-seven patients. At the follow-up, ranging from two to 59 weeks, the 30 day mortality rate was 7.4%. Twenty-eight patients had obvious clinical improvement with relief of jaundice. Seven patients experienced recurrent jaundice. In two of these patients, the obstruction was relieved by additional metallic stents. The expandable metallic biliary endoprosthesis is suggested as an effective treatment for biliary obstruction.

[Intraarterial urokinase infusion therapy for arterial occlusive disease of the pelvis and extremities with special reference to short-term high dose infusion]

Thirty-five complete arterial occlusions of pelvis and extremity in 29 patients were treated with intraarterial urokinase infusion therapy. In 28 limbs, the occlusions were due to arteriosclerotic change and in 7 lesions, the occlusions were due to Burger's disease. The patients with arteriosclerotic change ranged in age from 52 to 84 years with a mean age of 68 years, and the patients with Burger's disease ranged in age from 35 to 47 years with a mean age of 43 years. There were 24 men and 5 women. The estimated duration of the occlusion was from 5 days to 5 years with a mean duration of 11 months. The length of the occluded segments ranged from 1 to 45 cm with a mean length of 13.9 cm. The occlusion was located in the iliac artery in 13 patients, the femoral artery in 11 patients, both the iliac and the femoral artery in 2 patients, the popliteal artery in 5 patients, the femoro-popliteal artery in 1 patient, the brachial artery in 2 patients and the radial artery in 1 patient. The infusion catheter was gently advanced into the proximal portion of the clot over a flexible guide wire, and urokinase was infused at a rate of 5000-10000 IU/min, as a short term high dose infusion (SHI), until antegrade blood flow was reestablished. The catheter was then withdrawn to a point proximal to all of the remaining clot, and the infusion rate was reduced to 10000-20000 IU/h as a continuous low dose infusion (CLI). After thrombolytic recanalization, a percutaneous transluminal angioplasty (PTA) was performed in those cases which demonstrated a residual narrowing of the lumen. The initial success rate was 86%. Reocclusions were observed in 5 lesions (17%) and a second recanalization was successful in 2 of 3 patients. The 1-year cumulative patency rate following recanalization was 88.4% and the 2-year patency rate was 78.6%. No significant complications directly related to the procedure were observed. SHI combined with CLI and PTA appears to be an effective and safe therapy for chronic long segmental arterial occlusion.

[Computed tomography for the diagnosis of thrombosed aortic dissection with extravasation]

Four cases of thrombosed aortic dissection with extravasation demonstrated by CT were presented. In CT diagnosis for this type of dissection, cautions should be employed not only in an inhomogenous density area in the mediastinum and pleural cavity but also in the presence of deviation of intimal calcification and relatively high density area of crescent shape in aortic wall on plain CT.

[Treatment with expandable metallic stent for arterial occlusive disease]

Gianturco expandable metallic stents were used in 4 cases with ASO of the iliac artery after PTA for the purpose of the prevention of restenosis. The insertion of stent was succeeded in all 4 cases, and the improvement of clinical symptoms and elevation of ankle pressure index were observed. Follow-up over 3 to 8 months revealed no occlusion and migration of stent. Expandable metallic stent was suggested to be contributable to the treatment of arterial occlusive disease.

[Ultrasonic detectability of multiple small hepatic nodules]

We analyzed the ultrasonic detectability of multiple daughter nodules accompanied by 18 hepatocellular carcinomas and multiple small nodules in 11 metastatic liver tumors identified by infusion hepatic angiography. In the cases of hepatocellular carcinoma, ultrasonic detectability of daughter nodules was remarkably limited. If any daughter nodules are detected by US, there is the great possibility that many other daughter nodules are undetected. However, US is effective in detecting small nodules in the metastatic liver tumor.

[Non-vascular interventional radiology expandable metallic biliary endoprosthesis and afterloading intracavitary irradiation for malignant biliary obstruction]

Biliary endoprostheses (EMBE) using expandable metallic stents or intracavitary irradiation with remote afterloading (RALS) were carried out in eighteen patients with malignant biliary obstruction. There were 11 patients with bile duct cancer, 3 patients with gallbladder cancer, 2 patients with pancreas cancer and 2 patients with metastatic gastric cancer. The favourable results were obtained. Placement of stents was successful in all 17 cases in which the EMBE was conducted, and in all cases but one, the duct was cleared. At the follow-up of 2 to 59 weeks, all stents maintained patency and there were no severe complications, although only one patient had jaundice due to obstruction at the stented duct 4 months after EMBE. In nine cases, intracavitary irradiation with RALS was performed using a newly developed 14 Fr applicator. The bile duct walls at the irradiation site were smooth and expansion of the constricted area was seen. These results indicate that the combined use of EMBE and intracavitary irradiation with RALS could form a new part of treatment of malignant tumors of the bile duct in which radical surgery is not possible.

[An experimental and clinical study of thin-slice high-resolution CT for lung detail]

The clinical usefulness of thin-slice high-resolution CT in the diagnosis of the chest was assessed by (1) experiments using a phantom and an inflated fixed lung (Heitzman's method), (2) evaluation of the CT delineativity of the bronchi and major fissure and (3) clinical examination of patients with diffuse pulmonary diseases. 1) In a phantom experiment using catheters, 10 mm-thick slice scan showed the 6 catheters as a single faint line. By 1.5 mm-thick slice scan, the catheters were defined as 6 separate lines. The profile images suggested that 1.5 mm-thick slice scan enables delineation of more minute details of structures. 2) In an experiment using an inflated fixed lung, 1.5 mm-thick slice scan produced more informative images that resembled macroscopic or soft X-ray images. 3) By 1.5 mm-thick slice scan, the subsegmental bronchi of both the right and left lobes were identified in most cases, while identification was possible in only half the cases by 10 mm-thick slice scan. 4) By 10 mm-thick slice scan, the sub-subsegmental bronchi were not identified in most cases. However, identification was possible in approximately half the cases by 1.5 mm-thick slice scan. 5) By 1.5 mm-thick slice scan, the major fissure was delineated as a linear shadow in most cases. It was hardly recognizable by 10 mm-thick slice scan. 6) In diffuse pulmonary diseases, 1.5 mm-thick slice scan allowed more minute visualization of the patho-morphological changes compared to 10 mm-thick slice scan. 7) Thin-slice high-resolution CT is thus expected to contribute to pathological analysis and more accurate diagnosis of pulmonary diseases.

Afterloading intracavitary irradiation and expanding stent for malignant biliary obstruction

A double lumen catheter was developed as an applicator for the remote afterloading (RALS) of 60Co source for the intracavitary irradiation of an obstructed common bile duct caused by carcinoma of the gallbladder. This was followed by the placement of nylon-covered expandable metallic stents to maintain patency. This combination effectively provided palliation.