Palmaz stent deployment for subclavian and brachiocephalic arterial occlusive disease. Factors predictive of restenosis

SUMMARY

Palmaz stent deployment is a useful method for subclavian and brachiocephalic arterial occlusive disease. We evaluated restenosis or intimal thickening after Palmaz stent deployment for nine lesions of subclavian or brachiocephalic arterial occlusive disease focusing on stent diameter, atheroma thickness near the stent, and degree of coverage for the lesion. Follow up DSA and IVUS at 5-14 months (mean 9) after therapy showed no significant changes in the size or shape of the stent itself There were two lesions of thin in-stent intimal hyperplasia and five lesions of thick hyperplasia. There was no close relationship between intimal hyperplasia and stent diameter or atheroma size (relative thickness). There was some relationship between the degree of coverage of the lesion by the stent and degree of intimal hyperplasia, but to determine statistical significance, accumulation of a greater number of cases is necessary.

Detection of early venous filling in gliomas on MRI: preliminary study by 2D time-resolved dynamic contrast-enhanced MR angiography with echo-sharing technique

We evaluated the detection of early venous filling of gliomas by 2D time resolved dynamic contrast enhanced MR digital subtraction angiography (MR-DSA) with echo-sharing technique and compared the results with those of conventional contrast digital subtraction angiography (C-DSA). C-DSA and MR-DSA examinations were performed in eight patients with malignant gliomas and compared with regard to the visualization of early filling veins; time intensity curves of arteries, early filling veins and normal veins were made, and rise time and time to peak were evaluated. MR-DSA visualized 12 out of 17 early filling veins depicted on C-DSA. The failure of five veins to be depicted may be due to the overlapping of other structures, such as other vessels and tumor stain. On time intensity curves, the mean difference in rise time was 0.9 sec between the artery and early filling vein, and the mean difference of time to peak was 1.6 sec. C-DSA has been the modality of choice in demonstrating early venous filling, a useful finding in the differential diagnosis of gliomas. However the high temporal resolution of MR-DSA with echo-sharing technique provides sufficient visualization of early venous filling of gliomas. Additional information for precise differential diagnosis may be obtained by adding MR-DSA to the imaging protocol for gliomas.

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.

Enhancement pattern of normal extraocular muscles in dynamic contrast-enhanced MR imaging with fat suppression

PURPOSE

To evaluate the internal structure of normal extraocular muscles on fat-suppressed dynamic contrast-enhanced MR imaging.

MATERIAL AND METHODS

Ten subjects were examined using fat-suppressed dynamic contrast-enhanced MR imaging. We evaluated the enhancement pattern (C-shaped or ring-like) of extraocular muscles and quantified the maximum ratios of enhancement (Rmax) and maximum ratios of signal increase (Vmax). We also quantified Rmax and Vmax in the central and peripheral portions of medial rectus muscles.

RESULTS

In the early phase of dynamic contrast-enhanced MR imaging, a C-shaped or ring-like pattern was observed in 100% of inferior rectus, 95% of medial rectus, 55% of superior rectus, 20% of lateral rectus, and 15% of superior oblique muscles. Overall mean Rmax and Vmax values showed statistically significant differences to the temporal muscles. For the peripheral portion of medial rectus muscles, mean Rmax and Vmax values were greater than for the central portion.

CONCLUSION

Using fat-suppressed dynamic contrast-enhanced MR imaging, the C-shape or ring-like internal structure of the extraocular muscles could be visualized, and were considered to reflect their structure of orbital and global layers. Potential usefulness of the fat-suppressed dynamic contrast-enhanced MR imaging for detecting pathological status is suggested.

Histologic comparison of coronary and iliac atherectomy tissue from cases of in-stent restenosis

Pathologically, restenotic lesions after stenting were investigated by use of atherectomized tissues of seven coronary and seven iliac arteries. The mean interval of the stent deployment to restenosis was 9.1 months for the coronary artery and 33.7 months for the iliac artery, indicating a 3.7-fold longer interval for the latter. This study does not include cases of acute thrombotic occlusion. The atherectomized tissue from restenotic coronary arteries showed abundant neointima with alpha-actin-positive and ultrastructually synthetic-type smooth muscle cells in a rich myxomatous extracellular matrix. In the iliac arteries, the predominant component of restenosis consisted of organized thrombi. The neointima of the iliac arteries was mature, and only a small amount of spindle cells were observed in the hyalinized matrix. The tissue that developed restenosis after stenting was different in the coronary and iliac arteries included in this series. This study on the atherectomized tissue suggests that even in the chronic stage, a major cause of in-stent restenosis among the larger caliber vessels such as the iliac artery is not neointima but stent thrombosis.

Twin-tube endografts for aortic aneurysms: an experimental feasibility study

PURPOSE

To explore feasibility of twin-tube endografts (TTEGs) for treatment of abdominal aortic aneurysm (AAA).

MATERIALS AND METHODS

AAAs were created in six dogs by overdilation of Palmaz stents. TTEGs made of seven 9.5-mm-diameter Gianturco Rösch Z (GRZ) stents and covered with PTFE were deployed simultaneously from both femoral arteries through 10-F sheaths to exclude the AAA. Follow-up aortography was performed immediately and at 2, 4, and 8 weeks. Two dogs were killed at 4 weeks and four were killed at 8 weeks. Gross and histologic examinations were performed.

RESULTS

AAA creation and TTEG placement were successful in all six dogs. TTEGs completely excluded AAAs in five dogs. Minor temporary perigraft leak was seen in one dog immediately after stent placement. Four dogs had TTEGs patent to termination at 8 weeks. In two dogs with oversized TTEGs, one of the twin endografts occluded at 2 weeks. At autopsy, TTEGs were formed in semicircular shape and histology did not show any significant inflammatory reaction.

CONCLUSION

TTEGs show promise for treatment of AAA, with the potential of reducing the introductory sheath size. Further experimental studies, particularly with TTEGs extended into iliac arteries, are warranted.

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

PURPOSE

To evaluate the efficacy of antithrombotic agents in the prevention of stenosis of polytetrafluoroethylene (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.

Expandable metallic stent placement for nutcracker phenomenon

A 40-year-old woman presented with asymptomatic gross hematuria caused by the nutcracker phenomenon. Despite treatment with hemostatic agents and injection of silver nitrate into the renal pelvis, the hematuria had continued, and severe anemia (hematocrit 17%) had developed. We performed expandable metallic stent (EMS) placement across the left renal vein. Although mild hematuria continued, the anemia resolved after this interventional radiotherapy. EMS placement is a minimally invasive therapy for the nutcracker phenomenon.

Outcomes of stent-graft treatment of false lumen in aortic dissection

BACKGROUND

Stent-graft treatment for aortic disease promises to lead to a less invasive therapy than conventional surgical therapy. However, this treatment has not been established as a therapy for aortic dissection. The aim of this study was to examine the effect of stent-graft treatment of aortic dissection, as measured by follow-up data on entry site closure, clotting in the false lumen, and the outcome of the false lumen from the acute to chronic phase after operation.

METHODS AND RESULTS

We used a stent-graft of our own design to close the entry site of aortic dissection in 21 cases: 9 were acute (< 14 days), 8 subacute (< 6 months), and 4 chronic (> 6 months). Nine were type A and 12 were type B. In 15 cases, the stent-graft was inserted through the transverse arch, which had been surgically opened under median sternotomy. In the other 6 cases, the stent-graft was inserted by means of a transcatheter through a femoral artery. Using computed tomographic scans, we followed and examined clot formation in the false lumen and reduction in size of the false lumen at 3 levels: at the level of maximum aortic diameter, at the distal end of the stent-graft, and 50 mm distal to the stent-graft. The entry sites were successfully closed in 19 cases (90.4%); in the remaining 2 (both treated with a transcatheter) there was perigraft leakage into the false lumen. The hospital mortality rate of these stent-graft treatments was 14.3% (3 of 21). At 2 weeks after operation, the false lumen had completely clotted, respectively, in 100%, 77%, and 38% of cases at the 3 measurement levels. Substantial shrinkage (> 50% in diameter) of the false lumen at 6 months after the operation was observed in 72%, 60%, and 38% of cases at the respective levels. Shrinkage of the false lumen was particularly enhanced in patients treated within 6 months from the onset of dissection: The false lumen shrank by > 50% in 93%, 75%, and 50% of patients.

CONCLUSIONS

In cases of aortic dissection, the stent-graft is an effective tool for closing the entry site and promoting clot formation in the false lumen and for reducing the size of the false lumen within 6 months of the onset of dissection if the entry site has been closed.

Efficacy of Palmaz Stent Deployment for Subclavian Artery Stenosis

Percutaneous angioplasty is a useful method for improvement of posterior circulation of the brain in subclavian artery stenosis and occlusion. Recently, the Palmaz stent was introduced for peripheral vessels stenosis. We evaluated the efficacy and care point of Palmaz stent deployment for subclavian artery stenosis in seven cases (5 stenosis and 2 occlusion) with symptoms and a mean age of 65.1 years. The stents could be deployed exactly at the stenotic region in all cases.

The pressure gradient disappeared in all cases, and the clots were fixed between vessel wall and stent. Antegrade circulation and significant clinical symptoms improvement were obtained in all cases. In angioplasty of subclavian artery stenosis, as compared with balloon angioplasty alone, Palmaz stent is a very useful device with fewer complications including distal thrombosis of the vertebrobasilar circulation.

Ultrasonographic screening for arterial occlusive disease in the pelvis and lower extremities

PURPOSE

To evaluate the accuracy of pulsed Doppler ultrasound (PDUS) and color Doppler ultrasound (CDUS) for the screening of arterial occlusive disease in the pelvis and lower extremities.

METHODS

We studied 52 patients with intermittent claudication or lower extremity "coolness." Pulsed Doppler waveforms were measured in the inguinal and popliteal regions and were classified according to their pattern. Patients with abnormal waveforms underwent subsequent CDUS evaluation from the aortic bifurcation to the popliteal arteries. All patients also underwent conventional angiography.

RESULTS

All stenoses (> 50%) and occlusions on angiography were detected by PDUS. The combination of PDUS and CDUS allowed detection of 78.0% of stenotic lesions (> 50% narrowing) and 96.6% of occlusive lesions in the iliofemoral regions and in 100% of stenotic lesions (> 50% narrowing) and occlusive lesions in the femoropopliteal regions. PDUS required approximately 3 min. About more 5 min are required when CDUS was added.

CONCLUSION

Combined PDUS and CDUS appears to be a rapid, highly sensitive means of screening for arterial occlusive disease in the pelvis and lower extremities.

Age correlation of the time lag in signal change on EPI-fMRI

PURPOSE

We measured the time lags between the start or end of tasks and signal changes in functional MRI (fMRI) for various age groups and evaluated the age correlation of the time lags.

METHODS

Forty subjects, 20-76 years old, were evaluated. fMRI was performed with and echo planar imaging sequence at 0.5 s intervals. We measured the time for the signal of the precentral gyrus to make a half-maximal increase after starting the task (T-inc) and the time to reach the initial level after ceasing the task (T-dec).

RESULTS

Average T-inc was 3.09 s and T-dec was 6.63 s. The values of T-inc could be correlated to age. T-dec had no age correlation.

CONCLUSION

The time lag in fMRI was revealed to be prolonged with increasing age. Our results suggest that the time lag in fMRI is influenced by some factors associated with aging.

Normal myelination of anatomic nerve fiber bundles: MR analysis

PURPOSE

In order to establish milestones of brain maturation by MR imaging, we examined the initiation of myelination of fiber bundles and of surrounding white matter.

METHODS

The subjects included 54 healthy infants ranging in age from 35 to 145 weeks by corrected gestational age. Images were obtained on a 1.5-T MR unit. In 24 sites of 18 fiber bundles in eight cross sections obtained perpendicular to the long axis of the brain stem, we analyzed the initiation of myelination and the age at which fiber bundles become indistinguishable owing to myelination of the surrounding white matter (blurring).

RESULTS

The fiber bundles were classified into two groups on the basis of the presence or absence of blurring. The first group (no blurring) was further divided into group 1A, in which myelination began at 35 weeks or less, and group 1B, in which myelination began at 44 weeks or later. The second group (blurring) was divided into group 2A, in which myelination began at 35 weeks or less and blurring occurred at 43 to 49 weeks; group 2B, in which myelination started at 35 weeks or less and blurring began at 67 to 145 weeks; and group 2C, in which myelination began at 36 weeks or later and blurring occurred at 67 to 145 weeks.

CONCLUSION

The time of blurring, when myelinated fiber bundles become indistinguishable from surrounding white matter owing to the initiation of myelination, is considered to be a useful parameter of brain maturation in infancy.

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.

[Correlation between MR imaging and histopathological findings of cystic metastatic brain tumors]

To clarify the correlation between the histopathological findings and MR signal intensity of the cyst wall, fifteen cystic metastatic brain tumors of eleven patients were imaged using a 0.5T MR unit just before surgery, and the MRI findings were correlated with the histopathological findings of resected lesions. On T2-weighted images, all cyst walls showed hypointensity. On T1-weighted images, the intensity of the cyst wall could be classified into three groups, compared with the cerebral cortex. Walls with hyperintensity on T1WI(group H; n = 6) consisted of ample tumor cells, blood vessels and connective tissues, suggesting viable tumor cells. Iso-intense walls on T1W1(group I; n = 3)had abundant reactive glial tissues. Hypointense walls on T1W1 (group L; n = 5)revealed hemorrhage and/or hemosicerin in the wall, suggesting hemorrhagic necrosis. Thus a good correlation was demonstrated between the MR signal intensities and histopathological findings of cyst walls of cystic metastatic brain tumors. This may contribute not only to more precise diagnosis on MRI but also to more planning for treatment of cystic brain metastases.

[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.

[Color Doppler sonographic assessment of intrahepatic hemodynamics and shunt patency after transjugular intrahepatic portosystemic shunt (TIPS)]

The usefulness of color Doppler sonography for the assessment of intrahepatic hemodynamics and shunt patency was evaluated in a total of eight patients in whom the intrahepatic hemodynamics before and after transjugular intrahepatic portosystemic shunt (TIPS) could be serially examined by color Doppler sonography. In six of these patients the serial sonographic examinations could be followed for more than one year after TIPS creation. Within one month after TIPS creation, Vmax in the shunt was ranged from 87 cm/sec to 242 cm/sec (mean: 142.5 cm/ sec), and the flow direction in the right anterior portal vein was reversed in all patients. More than 70% stenosis of the shunt could be diagnosed by color Doppler sonography. When the shunt was confirmed by angiography to be more than 70% stenotic or occluded, Vmax in the shunt was decreased to less than 50 cm/sec and the blood flow in the right anterior portal vein become hepatopetal. From three months before stenosis or occlusion of the shunt, it was confirmed that Vmax in the shunt was less than 70 cm/sec or the blood flow of right anterior portal vein was hepatopetal. Color Doppler sonography was useful for the assessment of intrahepatic hemodynamics, and shunt patency and prediction of shunt stenosis or occlusion following TIPS creation.

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.

Systemic lupus erythematosus and anticardiolipin antibodies in Klinefelter's syndrome

A case report of Klinefelter's syndrome is presented that shows features of systemic lupus erythematosus, arteriographically-proven peripheral artery occlusion with leg ulcers, multiple cerebral infarcts and persistent elevations of anticardiolipin antibodies.

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.

Self-expandable spindle for transcatheter vascular occlusion: in vivo experiments. Work in progress

A mechanical vascular occluder was studied in eight pigs to test its efficacy in arteries of different diameters, stability over time, and safety in placement. The main component is a self-expandable spindle made of tubular stainless steel mesh. Simple steel spindles, double spindles, and Dacron-core spindles were placed in the common carotid artery, main renal artery, renal artery branches, and infrarenal aorta. Follow-up arteriograms were obtained immediately, 30-60 minutes, and (except for aortic spindles) 7 days after deployment. The left common carotid artery was occluded in all pigs, regardless of spindle type. In the main renal artery and its branches, simple steel spindles did not achieve complete occlusion. Double and Dacron-core spindles produced immediate occlusion without recanalization on the 1-week follow-up arteriogram, except for one spindle with an incomplete Dacron core and two spindles that did not completely fill the arterial lumen. Two Dacron-core spindles achieved immediate complete occlusion of the infrarenal aorta. No migration was seen with any spindle.

Portal decompression after transjugular intrahepatic portosystemic shunt creation with use of a spiral Z stent

PURPOSE

An experimental swine model of acute presinusoidal portal hypertension was used to investigate the feasibility of a spiral Z stent for transjugular intrahepatic portosystemic shunt (TIPS) placement and the correlation between the shunt (stent) size and degree of portal pressure decrease.

MATERIALS AND METHODS

Twelve young swine were used. Acute portal hypertension was induced by means of selective injections of absolute alcohol, ethiodized oil, and polyvinyl alcohol sponge particles into intrahepatic portal branches.

RESULTS

TIPS was successfully created in all swine by using spiral Z stents that were 6, 8, and 10 mm in diameter; each size stent was deployed in four animals. Being sufficiently flexible, spiral Z stents accommodated for curved shunt tracts. An average of 48% portal pressure decrease was achieved with 6-mm-diameter stents, 61% with 8-mm-diameter stents, and 87% with 10-mm-diameter stents.

CONCLUSION

These results are in agreement with our clinical experience with use of Gianturco-Rösch Z stents for TIPS formation.

Identification of pre- and postcentral gyri on CT and MR images on the basis of the medullary pattern of cerebral white matter

The authors illustrate a new method to identify the pre- and postcentral gyri on computed tomographic (CT) and magnetic resonance (MR) images of the brain on the basis of the pattern of the medullary branches of the cerebral white matter. The most commonly used method to identify the gyri depends on recognition of the central sulcus by surface arrangement of the sulci. The two methods were compared by analysis of CT images of 104 subjects who had normal findings (age range, newborn to 60 years; 57 males and 47 females). The usefulness of the new method was also determined in angiographic studies of nine patients with space-occupying lesions. The method is especially helpful for identification of gyri on the lower level of the centrum semiovale and if space-occupying lesions are present that may result in a blurred depiction of sulci. Since MR imaging depicts the medullary branches more clearly than does CT, this new method should facilitate identification of the gyri with either modality.

Intracerebral hemorrhage in carotid-cavernous fistula

This report describes a case of traumatic carotid-carvernous fistula which presented as an intracerebral hemorrhage. The usual ocular signs were absent due to an atypical drainage pattern from the cavernous sinus. Engorgement of the deep venous system of the brain due to the carotid-cavernous fistula was thought to have caused the intracerebral hemorrhage.

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.

Left-right asymmetry of the temporal and parietal regions in children: based on the medullary pattern of cerebral white matter

Lateralization of the posterior temporal lobe and inferior parietal lobule in childhood was studied on CT of 276 cases and compared with those in adulthood of 371 cases. CT images were analyzed based on the morphological features of medullary branches of the cerebral white matter. In children below 5 years of age, the left planum temporale was already more posteriorly located than the right in 56%, while the right was more so in 21%. The asymmetry of the middle temporal gyrus was similar to those of the planum temporale. The folding of the inferior parietal lobule was extensive and intricate on the left side in 63% and on the right side in 8% of children, almost identical to those in the adult. The visualization rates of the intraparietal sulcus were lower compared to those of the adult, but the higher visualization of the left side was a common tendency regardless of age. These alterations in left-right asymmetry seemed to be a morphologic substratum indicating the processes of localization of auditory function to those association areas.

[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.

MR and CT of tuberous sclerosis: linear abnormalities in the cerebral white matter

A review of MR and CT images in five patients, 8 months to 22 years old, diagnosed as having tuberous sclerosis, revealed linear abnormalities in the cerebral white matter. A linear abnormality connecting a subependymal nodule to a subcortical lesion was shown in two patients as an area of hypointensity on T1-weighted MR images and as an area of hyperintensity on T2-weighted images. These appeared as faintly high-density areas on CT images. Seventeen linear abnormalities extending from the ventricle to the cortex with a subependymal nodule or subcortical lesion on each end were visible in all five patients as areas of hyperintensity on the T2-weighted images. On the T1-weighted images, only nine hypointense lines were noted. CT scans did not show these latter lines. Linear abnormalities in cerebral white matter are suggestive of lesions of demyelination, dysmyelination, hypomyelination, or lines of migration disorder. MR imaging, especially T2-weighted, is particularly sensitive in detecting these abnormalities.

Improvement of T2-weighted images of central nervous system by motion artifact suppression technique (MAST)

Standard spin echo sequences of MRI with and without motion artifact suppression technique (MAST) were compared in 45 paired images of brain and 21 paired images of spine. The images were obtained on a Picker 1.5 T system with TR = 2 sec and TE = 100 or 120 msec. MAST is a method of refocusing transverse magnetization at echo time by modification of the gradient waveforms. Transverse, coronal, and sagittal planes of brain were compared in 10 paired images obtained from adults and five paired images from children. The spine was studied in sagittal images, 11 cervical images of adults, five lumbar images of adults, and five lumbar images of children. MAST was proven to be valuable not only for the detection of lesions but also for picturing anatomical details as in MR-cisternography and MR-myelography and the effects of iron ions. MAST improves significantly the quality of T2-weighted images, especially in children.

[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.

[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.