Trans-arterial embolization of a Yakes type IIb inferior mesenteric arteriovenous malformation: A case report and literature review for angio-architecture analysis.

We herein report a case of acute, massive lower gastrointestinal bleeding caused by Yakes type IIb inferior mesenteric arteriovenous malformation, which was successfully treated with endovascular embolization. The Yakes arteriovenous malformation classification provides curative treatment strategies based on specific angioarchitecture, thus serving as a valuable guide during treatment planning. We reviewed reported cases from 1988 to 2022 and conducted an angioarchitecture analysis based on the Yakes classification. We analyzed these reported cases to estimate the treatment success rates of surgery and embolization.

Characterization of hemodialysis fistulas experienced abrupt thrombosis and determination of a proper follow-up protocol: A retrospective cohort study and an interventionist's perspective.

Abrupt thrombosis is a form of thrombosis that occurs unexpectedly and without being preceded by hemodialysis fistula (AVF) dysfunction during dialysis. We found that AVFs with a history of abrupt thrombosis (abtAVF) appeared to have more episodes of thrombosis and required more frequent interventions than those without such history. Therefore, we sought to characterize the abtAVFs and examined our follow-up protocols to determine which one is optimal. We performed a retrospective cohort study using routinely collected data. The thrombosis rate, AVF loss rate, thrombosis-free primary patency, and secondary patency were calculated. Additionally, the restenosis rates of the AVFs under the follow-up protocol/sub-protocols and the abtAVFs were determined. The thrombosis rate, procedure rate, AVF loss rate, thrombosis-free primary patency, and secondary patency of the abtAVFs were 0.237/pt-yr, 2.702/pt-yr, 0.027/pt-yr, 78.3%, and 96.0%, respectively. The restenosis rate for AVFs in the abtAVF group and the angiographic follow-up sub-protocol were similar. However, the abtAVF group had a significantly higher thrombosis rate and AVF loss rate than AVFs without a history of abrupt thrombosis (n-abtAVF). The lowest thrombosis rate was observed for n-abtAVFs, followed up periodically under the outpatient or angiographic sub-protocols. AVFs with a history of abrupt thrombosis had a high restenosis rate, and periodic angiographic follow-up with a mean interval of 3 months was presumed appropriate. For selected populations, such as salvage-challenging AVFs, periodic outpatient or angiographic follow-up was mandatory to extend their usable lives for hemodialysis.

Quantitative physical examination indicators to detect patients with stenosis at a high risk of thrombosis at hemodialysis vascular access sites: A retrospective case-control study.

BACKGROUND: Quantitative physical examination (PE) indicators, including palpable pulsatility length and outflow scores, can be used to quantify stenosis severity at hemodialysis vascular access sites. It is known that the risk of high-shear-related thrombosis is increased when the minimal luminal diameter (MLD) of stenosis decreases. At present, MLD is measured using sonography or angiography. This study sought to determine the relationship between quantitative PE indicators and MLD and report their diagnostic performance in detecting patients with stenosis at a high risk of thrombosis. METHODS: We performed a retrospective case-control study using routinely collected data. We used the post-stenosis palpable pulsatility length (sPPL) and pulse-and-thrill based outflow score to assess the severity of AVF inflow and outflow stenosis, respectively. We recorded paired quantitative PE indicators and MLD before and after angioplasty in patients enrolled over a 4-month period. RESULTS: A total of 249 paired PE indicators and MLD measurements were obtained from 163 patients. A receiver operating characteristic curve analysis showed that an MLD cutoff value of <1.55 mm and an MLD of <1.95 mm discriminated sPPL = 0 and PESOS (physical examination significant outflow stenosis)/1- of the outflow score, respectively, from all other measurements, with the area under the curve values of 0.8922 and 0.9618, respectively. With sPPL = 0 and PESOS/1- of the outflow score as diagnostic tools to detect inflow stenosis with an MLD of ⩽1.5 mm and outflow stenosis with an MLD of ⩽1.9 mm at vascular access sites, sensitivity = 86.00% and 88.46%; specificity = 97.67% and 92.11%; positive predictive values of 97.73% and 92.00% and negative predictive values of 85.71% and 88.61%, respectively, were observed. CONCLUSIONS: Our preliminary results showed that physical examination can potentially be a diagnostic tool in detecting patients with stenosis who are at a high risk of thrombosis at hemodialysis vascular access sites with high diagnostic accuracy.

Quantification of the severity of outflow stenosis of hemodialysis fistulas with a pulse- and thrill-based scoring system.

BACKGROUND: Hyper-pulsatility of hemodialysis arteriovenous fistula (AVF) is the basic physical examination finding when there is outflow stenosis. The arm elevation test can also be utilized to detect outflow stenosis. If there is no significant outflow stenosis, the AVF should collapse, at least partially, because of the effect of gravity when the AVF-bearing arm is elevated to a level above that of the heart. However, if there is significant outflow stenosis, the portion of the AVF downstream of the stenosis will collapse, while the portion upstream of the stenosis will remain distended (Clin J Am Soc Nephro 8:1220-7, 2013). In our daily practice, when performing the arm elevation test, we not only observe the collapsibility of the access outflow but also palpate the outflow to identify a background thrill that sometimes disappears with the arm at rest, only to reappear when the arm is elevated. If there is no thrill upon arm elevation, we assume that the outflow stenosis is severe and refer to this condition as "physical examination significant outflow stenosis" (PESOS). The aim of this study is to characterize PESOS using percentage stenosis and Doppler flow parameters. METHODS: We performed a case-control study using data collected prospectively between June 2019 and December 2019. A pulse- and thrill-based score system was developed to assess the severity of AVF outflow stenosis. We recorded the outflow scores and Doppler measurements performed in 84 patients with mature fistulas over a 6-month period. Angiograms were reviewed to determine the severity of outflow stenosis, which was assessed by calculation of percentage stenosis. RESULTS: Receiver operating characteristic analysis showed that a cutoff value of ≥74.44% stenosis discriminated PESOS from other AVF outflow scores, with an area under the curve of 0.9011. PESOS diagnosed cases with ≥75% outflow stenosis in an AVF, with a sensitivity of 80.39%, a specificity of 78.79%, a positive predictive value of 85.42%, and a negative predictive value of 72.22%. CONCLUSIONS: PESOS can be used to diagnose ≥75% outflow stenosis in an AVF, with or without a significant collateral vein, and its diagnostic accuracy is high. The use of PESOS as an indicator for treatment implies that physical examination may represent a useful surveillance tool.

Percutaneous Extraanatomic Bypass for Treatment of Central Venous Occlusions in Patients Undergoing Hemodialysis.

OBJECTIVE. The pipeline technique has been described for percutaneous creation of a long extraanatomic bypass for a thrombosed hemodialysis vascular access in patients with outflow veins that cannot be recanalized. However, when we used the pipeline technique in nonthrombotic vascular access sites to create a bypass to treat central venous occlusion, we encountered two technical challenges not mentioned in previous reports: bleeding from the peripheral incision and difficulty in pushing the stent-graft catheter through the subcutaneous track. CONCLUSION. We report our solutions for these two technical challenges and the treatment outcomes of percutaneous extraanatomic bypass for central venous occlusion in patients undergoing hemodialysis with access-related upper limb swelling.

Measuring the palpable pulsatility length as a physical examination test in defining the severity of inflow stenosis for hemodialysis fistulas.

BACKGROUND: Pulsatility is an important property of hemodialysis arteriovenous fistulas (AVF) and can be perceived by the fingers as a gradual decrease in strength downstream from the anastomosis along the main trunk of the fistula. The distance from the point at which the pulse becomes imperceptible to the anastomosis is termed the palpable pulsatility length (PPL); we considered this length may play a role in assessing the severity of inflow stenosis for hemodialysis fistulas. METHODS: This study was performed by retrospective analysis of routinely collected data. Physical examinations and fistula measurements were performed in a selected population of 76 hemodialysis patients with mature fistulas during half a year. Fistula measurements included the PPL before and after treatment and the distance between the anastomosis and the arterial cannulation site (aPump length). The aPump index (API) was calculated by dividing the PPL by the aPump length. Angiograms were reviewed to determine the location and severity of stenosis. PPL and API were used to detect the critical inflow stenosis, which indicates severe inflow stenosis of an AVF. RESULTS: Receiver operating characteristic analysis showed that the area under the curve was 0.895 for API and 0.878 for PPL. A cutoff value of API < 1.29 and PPL < 11.0 cm were selected to detect the critical inflow stenosis. The sensitivity was 96.0% versus 80.0% and specificity was 84.31% versus 84.31% for API and PPL, respectively. CONCLUSIONS: PPL and API are useful tools in defining the severity of pure inflow stenosis for mature AVFs in the hands of trained examiners with high sensitivity and specificity.

Endovascular bypass for salvage of vascular access in hemodialysis catheter-consigned patients.

PURPOSE:: This study was performed to retrospectively assess the efficacy of percutaneous creation of an intervascular bypass with or without stent graft deployment (endovascular bypass) for salvage of abandoned vascular access sites in hemodialysis catheter-consigned patients. METHODS:: Salvage of abandoned vascular access sites was attempted in 16 patients with hemodialysis catheters. These vascular access sites were salvaged using endovascular bypass techniques to redirect the access flow to a nonarterialized vein as a new outflow conduit or cannulation segment. The postintervention primary, assisted primary, and secondary patency rates of the access site and bypass were calculated using the Kaplan-Meier method. RESULTS:: The procedural and clinical success rates were both 100%. The postintervention primary patency rate of the bypass and access site at 360 days was 75.7 ± 12.5% and 56.8 ± 14.9%, respectively. The mean follow-up period was 461.9 days (range: 121-900 days). No major complications were observed. One bare bypass tunnel rupture and one pseudoaneurysm were noted during the procedure. CONCLUSION:: Salvage of abandoned vascular access sites for hemodialysis catheter-consigned patients can be technically feasible and clinically successful using endovascular bypass techniques in selected patients when surgical revision is not considered or is not possible.

The Complication of Hepatic Artery Injuries of 1,304 Percutaneous Transhepatic Biliary Drainage in a Single Institute.

PURPOSE: To determine frequency of and assess risk factors for hepatic artery (HA) injury during percutaneous transhepatic biliary drainage (PTBD) and to discuss the technique and report the clinical outcome of embolization for HA injury. MATERIALS AND METHODS: Over a 14-year period (2002-2016), 1,304 PTBD procedures in 920 patients were recorded. The incidence of HA injury was determined, and possible associated risk factors were analyzed. When injury occurred, HA embolization was performed at the site as close to the bleeding point as possible. Clinical outcomes of these patients after embolization were reported. RESULTS: Of 1,304 PTBD procedures, a left-sided approach was used in 722 procedures (55.4%), and intrahepatic duct (IHD) puncture under ultrasound guidance was used in 1,161 procedures (90.1%). The IHD was nondilated in 124 (9.5%) patients. The punctured ductal entry site was peripheral in 1,181 (90.6%) patients. In this series, 8 procedures (0.61%) were complicated by HA injury. IHD dilatation status was the only risk factor (P = .017) for HA injury. Embolization was performed with technical and clinical success in all 8 patients. No recurrent hemobilia, intraabdominal bleeding, or other sequelae of HA injury after embolization was noted during 1 week to 84 months of follow-up. CONCLUSIONS: HA injury is a relatively rare complication of PTBD. IHD dilatation status was the only risk factor for HA injury in this study. When HA injury occurred, embolization therapy was effective in managing this complication.

The use of a Colapinto TIPS Needle under cone-beam computed tomography guidance for true lumen re-entry in subintimal recanalization of chronic iliac artery occlusion.

BACKGROUND: To report the technique and clinical outcome of subintimal re-entry in chronic iliac artery occlusion by using a Colapinto transjugular intrahepatic portosystemic shunt (TIPS) needle under rotational angiography (cone-beam computed tomography; CT) imaging guidance. METHODS: Patients with chronic iliac artery occlusion with earlier failed attempts at conventional percutaneous recanalization during the past 5 years were enrolled in our study. In these patients, an ipsilateral femoral access route was routinely utilized in a retrograde fashion. A Colapinto TIPS Needle was used to aid the true lumen re-entry after failed conventional intraluminal or subintimal guidewire and catheter-based techniques. The puncture was directed under rotational angiography cone-beam CT guidance to re-enter the abdominal aorta. Bare metallic stents 8-10 mm in diameter were deployed in the common iliac artery, and followed by balloon dilation. RESULTS: Ten patients (9 male; median age, 75 years) were included in our investigation. The average occlusion length was 10.2 cm (range, 4-15 cm). According to the Trans-Atlantic Inter-Society Consensus (TASC) II classification, there were five patients each with Class B and D lesions. Successful re-entry was achieved in all patients without procedure-related complications. The ankle-brachial index (ABI) values increased from 0.38-0.79 to 0.75-1.28 after the procedure. Imaging follow-up (> 6 months) was available in six patients with patency of all stented iliac artery. Thereafter, no complaints of recurrent clinical symptoms occurred during the follow-up period. CONCLUSION: The use of Colapinto TIPS needle, especially under cone-beam CT image guidance, appears to be safe and effective to re-enter the true lumen in a subintimal angioplasty for a difficult chronic total iliac occlusion.

Use of a portal vein localization sheath in the single-needle pass technique for creation of a portosystemic shunt.

This study aimed to report a modification to the single-needle pass technique by use of a portal vein localization sheath for creation of a portosystemic shunt. The modification makes the single-needle pass technique a more straightforward procedure.

The pipeline technique: a simple endovascular technique for creation of a jump graft bypass.

PURPOSE: The purpose of this study is to describe a technique by which a bypass was created percutaneously with two overlapping covered stents for salvage of a thrombotic right brachial-axillary arteriovenous graft without recanalizable outflow. METHODS AND RESULTS: With the pipeline technique, a 16 cm bypass tract covered with two overlapping Viabahn stents between the hemodialysis graft and the right subclavian vein was created as an alternative access outflow. The hemodialysis graft was successfully salvaged without complications and functioned well for more than 6 months except for one thrombosis which occurred 147 days after its salvage. CONCLUSIONS: We describe an endovascular bypass technique using a sheath-dilator set and two angiographic catheters to salvage a thrombotic hemodialysis graft.

Percutaneous Creation of Bare Intervascular Tunnels for Salvage of Thrombosed Hemodialysis Fistulas Without Recanalizable Outflow.

PURPOSE: This study aimed to retrospectively assess the efficacy of a bare intervascular tunnel for salvage of a thrombosed hemodialysis fistula. We examined the clinical outcomes and provided follow-up images of the bare intervascular tunnel. MATERIALS AND METHODS: Eight thrombosed fistulas lacked available recanalizable outflow veins were included in this study. These fistulas were salvaged by re-directing access site flow to a new outflow vein through a percutaneously created intervascular tunnel without stent graft placement. The post-intervention primary and secondary access patency rates were calculated using the Kaplan-Meier method. RESULTS: The procedural and clinical success rates were 100%. Post-intervention primary and secondary access patency at 300 days were 18.7 ± 15.8 and 87.5 ± 11.7%, respectively. The mean follow-up period was 218.7 days (range 10-368 days). One patient died of acute myocardial infarction 10 days after the procedure. No other major complications were observed. Minor complications, such as swelling, ecchymosis, and pain around the tunnel, occurred in all of the patients. CONCLUSIONS: Percutaneous creation of a bare intervascular tunnel is a treatment option for thrombosed hemodialysis fistulas without recanalizable outflow in selected patients.

Pharmaco-induced vasospasm therapy for acute lower gastrointestinal bleeding: a preliminary report.

PURPOSE: To report a novel technique and preliminary clinical outcomes in managing lower gastrointestinal bleeding (LGIB). MATERIALS AND METHODS: Eighteen LGIB patients (11 men and 7 women, mean age: 66.2 years) were treated with artificially induced vasospasm therapy by semi-selective catheterization technique. Epinephrine bolus injection was used to initiate the vascular spasm, and followed by a small dose vasopressin infusion (3-5 units/h) for 3h. The technical success, clinical success, recurrent bleeding and major complications of this study were evaluated and reported. RESULTS: Sixteen bleeders were in the superior mesenteric artery and 2 in the inferior mesenteric artery. All patients achieved successful immediate hemostasis. Early recurrent bleeding (<30 days) was found in 4 patients with local and new-foci re-bleeding in 2 (11.1%) each. Repeated vasospasm therapy was given to 3 patients, with clinical success in 2. Technical success for the 21 bleeding episodes was 100%. Lesion-based and patient-based primary and overall clinical successes were achieved in 89.4% (17/19) and 77.7% (14/18), and 94.7% (18/19) and 88.8% (16/18), respectively. None of our patients had complications of bowel ischemia or other major procedure-related complications. The one year survival of our patients was 72.2 ± 10.6%. CONCLUSIONS: Pharmaco-induced vasospasm therapy seems to be a safe and effective method to treat LGIB from our small patient-cohort study. Further evaluation with large series study is warranted. Considering the advanced age and complex medical problems of these patients, this treatment may be considered as an alternative approach for interventional radiologists in management of LGIB.

Endovascular salvage of immature autogenous hemodialysis fistulas.

PURPOSE: To report the technical success and long-term clinical outcomes of immature arteriovenous fistula (AVF) after percutaneous angioplasty (PTA). MATERIALS AND METHODS: Patients with 58 immature AVF underwent PTA treatment in our institute during the past 9 years. Based on pretreatment ultrasound findings, the immature AVFs were categorized as stenosed, thrombosed, and obliterated type. An optimal entry site was punctured under ultrasound guidance followed by conventional fluoroscopy-guided PTA technique. Technical and clinical success as well as complications were recorded. Patency after angioplasty was estimated using Kaplan-Meier analysis. Predictors of patency were estimated using log-rank test. RESULTS: In our series, 50 % (29 of 58), 20.7 % (12 of 58), and 29.3 % (17 of 58) of immature AVF were stenosed, thrombosed, and obliterated, respectively. Technical and clinical success was achieved in 96.6 % (56 of 58) of cases with 100 % success in both the stenosed and thrombosed lesions and 88.2 % (15 of 17) success in the obliterated lesions. Vascular ruptures occurred in 12.1 % (7 of 58) of lesions. The overall primary and secondary patency rates of the 58 lesions were 45.4 and 84.2 % at 12 months and 36.5 and 80.1 % at 36 months. There were no significant differences of patency between the three types of lesions (p = 0.075 and 0.093) and the two groups of patients with or without residual side branches after intervention (p = 0.527 and 0.644). There was a significant difference of primary patency in patients with vascular rupture (p = 0.012) with a hazard ratio of 3.236. CONCLUSION: PTA could effectively prolong the lifetime of immature AVFs with high technical success. Vessel rupture was predictive of shorter primary patency, and long-term secondary patency was acceptable.

Treatment of hemodialysis vascular access rupture irresponsive to prolonged balloon tamponade: retrospective evaluation of the effectiveness of N-butyl cyanoacrylate seal-off technique.

OBJECTIVE: The current study retrospectively evaluated whether the percutaneous N-butyl cyanoacrylate (NBCA) seal-off technique is an effective treatment for controlling the angioplasty-related ruptures, which are irresponsive to prolonged balloon tamponade, during interventions for failed or failing hemodialysis vascular accesses. MATERIALS AND METHODS: We reviewed 1588 interventions performed during a 2-year period for dysfunction and/or failed hemodialysis vascular access sites in 1569 patients. For the angioplasty-related ruptures, which could not be controlled with repeated prolonged balloon tamponade, the rupture sites were sealed off with an injection of a glue mixture (NBCA and lipiodol), via a needle/needle sheath to the rupture site, under a sonographic guidance. Technical success rate, complications and clinical success rate were reported. The post-seal-off primary and secondary functional patency rates were calculated by a survival analysis with the Kaplan-Meier method. RESULTS: Twenty ruptures irresponsive to prolonged balloon tamponade occurred in 1588 interventions (1.3%). Two technical failures were noted; one was salvaged with a bailout stent-graft insertion and the other was lost after access embolization. Eighteen accesses (90.0%) were salvaged with the seal-off technique; of them, 16 ruptures were completely sealed off, and two lesions were controlled as acute pseudoaneurysms. Acute pseudoaneurysms were corrected with stentgraft insertion in one patient, and access ligation in the other. The most significant complication during the follow-up was delayed pseudoaneurysm, which occurred in 43.8% (7 of 16) of the completely sealed off accesses. Delayed pseudoaneurysms were treated with surgical revision (n = 2), access ligation (n = 2) and observation (n = 3). During the follow-up, despite the presence of pseudoaneurysms (acute = 1, delayed = 7), a high clinical success rate of 94.4% (17 of 18) was achieved, and they were utilized for hemodialysis at the mean of 411.0 days. The post-seal-off primary patency vs. secondary patency at 90, 180 and 360 days were 66.7 ± 11.1% vs. 94.4 ± 5.4%; 33.3 ± 11.1% vs. 83.3 ± 8.8%; and 13.3 ± 8.5% vs. 63.3 ± 12.1%, respectively. CONCLUSION: Our results suggest that the NBCA seal-off technique is effective for immediate control of a venous rupture irresponsive to prolonged balloon tamponade, during interventions for hemodialysis accesses. Both high technical and clinical success rates can be achieved. However, the treatment is not durable, and about 40% of the completely sealed off accesses are associated with developed delayed pseudoaneurysms in a 2-month of follow-up. Further repair of the vascular tear site, with surgery or stent-graft insertion, is often necessary.

TIPS in patients with cranial porta hepatis: ultrasound-guided transhepatic portohepatic-portocaval puncture in single needle pass.

OBJECTIVE: The purpose of this study was to describe our technique of transhepatic serial puncture of the portal vein and hepatic vein-inferior vena cava in one needle pass under ultrasound guidance to place a transjugular intrahepatic portosystemic shunt (TIPS) in patients with a porta hepatis cranial to the usual location. MATERIALS AND METHODS: Six patients (five men, one woman) underwent transhepatic TIPS procedures at our institution. The indications for portal decompression were recurrent variceal bleeding in four patients and refractory ascites and hydrothorax in one patient each. In five patients initial attempts at a classic transjugular approach failed because of an unusual angle between the hepatic vein and the portal vein; in the other patient, revision of an occluded shunt had failed. Two patients had main portal vein thrombosis. RESULTS: Technical success was achieved in all six patients. Two patients received a portohepatic venous shunt and four a portocaval shunt (inferior vena cava to right portal vein in three patients and inferior vena cava to left portal vein in one patient).The portosystemic pressure gradient before TIPS was 17-35 mm Hg and after TIPS was 6-10 mm Hg. No procedure-related complications occurred. One patient had severe hepatic encephalopathy. Two patients had shunt occlusion, which was successfully revised 17 and 10 months after the procedure. CONCLUSION: Our technique is a safe, effective, and universally applicable method for establishment of a TIPS in patients with either normal venous anatomy or severely distorted liver parenchyma.

Endovascular revascularization of chronically thrombosed arteriovenous fistulas and grafts for hemodialysis: a retrospective study in 15 patients with 18 access sites.

The current study retrospectively evaluated whether endovascular revascularization of chronically thrombosed and long-discarded vascular access sites for hemodialysis was feasible. Technical and clinical success rates, postintervention primary and secondary patency rates, and complications were reported. During a 1-year period, we reviewed a total of 924 interventions performed for dysfunction and/or failed hemodialysis vascular access sites and permanent catheters in 881 patients. In patients whose vascular access-site problems were considered untreatable or were considered treatable with a high risk of failure and access-site abandonment, we attempted to revascularize (resurrect) the chronically occluded and long-discarded (mummy) vascular access sites. We attempted to resurrect a total of 18 mummy access sites (mean age 46.6 ± 38.7 months; range 5-144) in 15 patients (8 women and 7 men; mean age 66.2 ± 11.5 years; age range 50-85) and had an overall technical success rate of 77.8%. Resurrection failure occurred in 3 fistulas and in 1 straight graft. The clinical success rate was 100% at 2 months after resurrection. In the 14 resurrected vascular access sites, 6 balloon-assisted maturation procedures were required in 5 fistulas; after access-site maturation, a total of 22 interventions were performed to maintain access-site patency. The mean go-through time for successful resurrection procedures was 146.6 ± 34.3 min (range 74-193). Postmaturation primary patency rates were 71.4 ± 12.1% at 30 days, 57.1 ± 13.2% at 60 days, 28.6 ± 13.4% at 90 days, and 19 ± 11.8% at 180 days. Postmaturation secondary patency rates were 100% at 30, 60, and 90 days and 81.8 ± 11.6% at 180 days. There were 2 major complications consisting of massive venous ruptures in 2 mummy access sites during balloon dilation; in both cases, prolonged balloon inflation failed to achieve hemostasis, but percutaneous N-butyl cyanoacrylate glue seal-off was performed successfully. Percutaneous resurrection of mummy vascular access sites for hemodialysis is technically feasible with high clinical success rates. In selected patients, resurrection of mummy access sites provides long-discarded access sites one more chance to be used for hemodialysis in an effort to preserve potential extremity sites for future access-site placement and to prevent long-term catheter indwelling.

Single-dose time-resolved contrast enhanced hybrid MR angiography in diagnosis of peripheral arterial disease: compared with digital subtraction angiography.

PURPOSE: To prospectively study the diagnostic performance of hybrid single-dose contrast-enhanced MRA of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: Hybrid MRA, combining time resolved imaging of contrast kinetics and two-station bolus-chase sequences, of lower limb was performed in 31 PAD patients (21 men, 10 women; mean age, 72 years) with two separate gadobenate dimeglumine (8 mL) injections in each sequence. Two independent blinded readers analyzed the vascular stenosis (32 segments in each limb). Sensitivity, specificity, and accuracy in all vascular segments and segments below popliteal artery were calculated. Interobserver agreements on MRA and intermodality agreements between MRA and DSA were calculated by using k statistics. RESULTS: Sensitivity, specificity, and accuracy of the hybrid MRA with regard to hemodynamically significant stenosis in all vascular segments were 92%, 97%, and 95% for reader 1, and 90%, 92%, and 92%, for reader 2, respectively. The interobsever agreements on MRA were good (k = 0.77-0.74) for all-grade stenosis, and excellent (k = 0.82-0.81) for hemadynamically significant stenosis. The intermodality agreements are good to excellent (k = 0.73-0.94). CONCLUSION: Single-dose hybrid MRA is a safe and reliable noninvasive alternative to conventional DSA in the assessment of PAD patients.

Hepatic artery infusion catheter implantation without embolization of the gastroduodenal artery in cases of retrograde blood flow.

Between January 2007 and January 2008, a port/catheter system for hepatic arterial infusion chemotherapy was implanted in seven patients with retrograde blood flow in the gastroduodenal artery (GDA). The GDA was not coil-embolized when the catheter tip was positioned in the right gastroepiploic artery. In all cases, implantation of the port/catheter system was successful, and there were no complications. Interventionalists can economize on expensive microcoils by using this simple and time-saving method.

The usefulness of fast-spin-echo T2-weighted MR imaging in Nutcracker syndrome: a case report.

Nutcracker syndrome occurs when the left renal vein (LRV) is compressed between the superior mesenteric artery and the aorta, and this syndrome is often characterized by venous hypertension and related pathologies. However, invasive studies such as phlebography and measuring the reno-caval pressure gradient should be performed to identify venous hypertension. Here we present a case of Nutcracker syndrome where the LRV and intra-renal varicosities appeared homogeneously hyperintense on magnetic resonance (MR) fast-spin-echo T2-weighted imaging, which suggested markedly stagnant intravenous blood flow and the presence of venous hypertension. The patient was diagnosed and treated without obtaining the reno-caval pressure gradient. The discomfort of the patient lessened after treatment. Furthermore, on follow-up evaluation, the LRV displayed a signal void, and this was suggestive of a restoration of the normal LRV flow and a decrease in LRV pressure.