Dominant outflow vein occlusion in the management of naturally occurring peripheral arteriovenous anomalies in cats and dogs.

Two dogs and 1 cat were referred to a tertiary veterinary center for the consultation and treatment of limb edema, variable dermal sanguineous crusting lesions, and intermittent lameness. A peripheral arteriovenous anomaly (PAA) was diagnosed via computed tomographic angiography (CTA) in each case. Arteriography enabled further evaluation of the PAA with confirmation of a dominant outflow vein. Dominant outflow vein occlusion was achieved by direct ligation in 1 dog and retrograde transvenous glue embolization in the cat and other dog. Repeat arteriography demonstrated resolution of arteriovenous shunting. Presenting clinical signs resolved in all animals. The previously identified aberrant vessels in 1 dog were not identified after CTA 40 days postoperatively. No postoperative complications or recurrence was identified in any case during the 6- to 55-month follow-up period.

Embolization Techniques for Arteriovenous Malformations in Parkes-Weber Syndrome.

BACKGROUND: Multiple high-flow arteriovenous malformations (AVMs) are the hallmark of Parkes-Weber syndrome (PWS). Surgical resection has historically shown poor outcomes with PWS. The aim of this study was to assess the management of PWS in the current era. METHODS: A retrospective review was performed from 2004 to 2017 on all patients presenting to a single institution for the management of PWS. Presentation, techniques, complications, and outcomes were reviewed. RESULTS: Fourteen patients (50% male) with PWS were seen at our institution, and mean age was 19.9 years (range, 4.7-68.8). The lower extremity was affected in 12 (86%) and the upper extremity in 2 (14%) patients. All patients presented with pain and swelling in the affected limb. Seven (50%) patients presented with ulcers, of which 3 (43%) had extensive wounds. Five (36%) patients had echocardiographic evidence of high-output cardiac failure. All patients underwent angiography with the intention to treat. Three (21%) patients were found to have diffuse arteriovenous communication with no discrete AVM nidus and thus did not undergo intervention. The remaining 11 (79%) patients underwent transcatheter embolization of the AVM's arterial inflow. Six (55%) patients required multiple or staged inflow embolization procedures, with a mean of 3.3 (range, 1-10) interventions. Thirty-two arterial embolization procedures were performed in total. n-Butyl-2-cyanoacrylate (nBCA) adhesive was used in 22 (69%), microspheres in 8 (25%), and a combination of coils and nBCA adhesive in 2 (6%) cases. Technical angiographic success was seen in all patients. Six (55%) patients also had interventions to treat the venous component of the malformation, either concomitantly or during a separate procedure. This included radiofrequency ablation in 1 (17%), coil embolization in 1 (17%), sodium tetradecyl sulfate (STS) sclerotherapy in 2 (33%), and a combination of STS, coil embolization, and vein stripping in 2 (33%) patients. Ten (91%) patients experienced a partial response and 1 (9%) patient experienced no response to treatment. No patients had a complete response, as expected with the diffuse nature of this disease. There were no periprocedural complications. Two of 3 patients with complex wounds required major amputations for gangrene, including one above-knee and one below-knee amputation at 128 months and 66 months after the index procedure, respectively. CONCLUSIONS: AVMs in PWS can be successfully treated by a transcatheter approach. Multiple interventions are usually required. Patients with extensive wounds remain at risk for loss of limb.

Major Limb Amputations in Patients with Congenital Vascular Malformations.

BACKGROUND: The need for major amputations in patients with vascular malformations is rare. This study reviews our contemporary experience with major amputations in patients with vascular malformations. METHODS: A retrospective review from April 2014 to November 2018 identified 993 patients undergoing management of a vascular malformation involving the upper or lower extremity at a tertiary center. This population was analyzed to identify those requiring either a transfemoral or transhumeral amputation. This cohort was investigated for clinical course, surgical procedures, and outcomes. RESULTS: Five patients (0.5%) underwent major amputation, including 3 transhumeral and 2 above-knee amputations. The median age was 37.8 years (interquartile range (IQR): 25.4-40.2), and 2 (40%) were male. Four (80%) patients had high-flow arteriovenous malformations, including 1 (20%) with Parkes-Weber syndrome. One (20%) patient had a low-flow venous malformation associated with Klippel-Trénaunay syndrome. All patients had malformation extending into the chest or pelvis, with the amputation being at the level of residual malformation. As such, amputation had been initially felt to be high risk because of the proximal extent of the lesions. Before amputation, a median of 11 procedures (IQR: 4-39) were performed per patient. This included 29 transarterial embolizations, 4 transvenous embolizations, 20 direct stick embolizations, 3 debulking procedures, 38 debridements, 6 skin grafts or muscle flaps, and 4 minor amputations. The median time course of treatment before amputation was 117 months (IQR: 44-171). Indications for major amputation included chronic pain and recurrent bleeding in all 5 (100%) patients, loss of function in 2 (40%), nonhealing wounds in 2 (40%), and sepsis in 1 (20%) patient. There were no perioperative deaths. The median blood loss was 1,000 mL (IQR: 650-2,750). All patients required transfusion of packed red blood cells with a mean of 1.6 units (standard deviation: 0.54). Transhumeral amputation was facilitated by transcatheter embolization in 1 (33%) and an occlusion balloon within the subclavian artery in 2 (66%) patients. The median length of stay was 6 days (IQR: 5-13). The median length of follow-up was 132 months (IQR: 68-186) from initial intervention and 12 months (IQR: 8-31) from amputation. Two patients (40%) who had undergone transhumeral amputation required revision of the amputation site for recurrent ulceration at 2 and 38 months. Of these, 1 patient underwent 3 transcatheter embolization procedures before revision and 1 underwent 1 embolization after revision. CONCLUSIONS: Although rare, successful amputation at the level of residual malformation can be performed in select patients with refractory complications of vascular malformations including intractable pain, bleeding, or nonhealing wounds. Specific preoperative and intraoperative measures may be critical to achieve satisfactory outcomes, and endovascular techniques continue to play a role after amputation.

Use of percutaneous foam sclerotherapy with 1.5% sodium tetradecyl sulfate for treatment of a pelvic limb venous malformation in a dog.

CASE DESCRIPTION: A 6-year-old 17-kg (37.4-lb) spayed female mixed-breed dog was evaluated because of swelling and intermittent lameness of the right pelvic limb and perianal and vulvar bleeding caused by a suspected arteriovenous malformation. CLINICAL FINDINGS: The right pelvic limb had a diffuse, raised, cobblestone-like appearance with lameness, edema, and multifocal ulcerations. The abdominal skin had multifocal circular erythematous lesions, the perianal region was erythematous, and the vestibule had superficial distended vessels. Ultrasonography and CT did not reveal the presence of an arteriovenous malformation; however, digital subtraction venography confirmed the presence of a venous malformation (VM) throughout the limb. TREATMENT AND OUTCOME: A mixture of foam sclerosant (1.5% sodium tetradecyl sulfate) and contrast medium was agitated with air and injected percutaneously into the VM. The dog received an injection of corticosteroid solution, and a soft-padded bandage was applied to the limb for 3 days. Six weeks later, the dog would intermittently hop when running, and the limb was mildly edematous with ecchymotic lesions; the swelling and lameness had improved considerably. Perianal and vulvar bleeding and dilation of the vestibular vessels had resolved. At 21 months after the procedure, examination revealed no right pelvic limb lameness related to the VM; only small cyst-like lesions and edema around the tarsus remained. CLINICAL RELEVANCE: The favorable clinical outcome for this dog for a 21-month period after treatment of a pelvic limb VM with foam sclerotherapy has suggested that foam sclerotherapy may be used to successfully treat limb VMs in some dogs.

Arteriovenous Malformations: Syndrome Identification and Vascular Management.

PURPOSE OF REVIEW: Vascular malformations represent a poorly understood set of conditions that create considerable diagnostic and therapeutic confusion. Historically, extensive surgical resections yielded poor results. More recently, the treatment paradigm has shifted to endovascular therapy such that embolization and sclerotherapy are now considered the first line of treatment. Although there is still a role for traditional surgical techniques, it is now most commonly integrated with endovascular therapies in a hybrid fashion. The goal of this review is to provide a greater understanding of the diagnosis and treatment of vascular malformations. RECENT FINDINGS: Vascular malformations can be high-flow (arteriovenous shunting) or low-flow (venous or lymphatic). Clinical presentation and treatment is different for each. Treatment of high-flow lesions must be directed at reducing or eliminating the nidus, usually via super-selective catheterization and embolization. Low-flow lesions are usually treated by direct injection of sclerosing agents under fluoroscopic or ultrasound guidance. The cornerstone of managing patients with vascular malformations is making the proper diagnosis, which is often challenging. Even after a diagnosis is made, therapy itself may be challenging and generate frustration among patients and providers. Frequently, the treatment of vascular malformations is characterized by only slow and incremental improvements without complete lesion eradication. By combining a thorough understanding of the vascular malformation disease process with an array of endovascular techniques, vascular interventionalists may contribute greatly to the care of these patients.

Embolization techniques for high-flow arteriovenous malformations with a dominant outflow vein.

OBJECTIVE: The aim of this study was to assess the management and outcomes of arteriovenous malformations (AVMs) with a dominant outflow vein (DOV) treated with retrograde venous embolization. METHODS: A retrospective review was performed from November 2010 to May 2014 on all patients with a high-flow AVM and associated DOV who underwent transvenous embolization of the DOV. Indications, techniques, complications, and outcomes were reviewed. RESULTS: Fourteen patients (five male; 36%) underwent transvenous embolization of high-flow AVMs with a DOV. Median age was 41.6 years (15.7-65.8 years). The AVM was located on an extremity in eight patients (57%) and in the pelvis in six patients (43%). The indication for the procedure was pain in 11 patients (79%), swelling in 3 patients (21%), a nonhealing wound in 1 patient (7%), and impotence in 1 patient (7%). The median number of prior procedures to treat the AVM was 2.5 (0-13). Transvenous embolization with coils was performed in 13 patients (93%). The Amplatzer vascular plug and Amplatzer septal occluder (St. Jude Medical, St. Paul, Minn) were used in four patients (29%). Concurrent percutaneous puncture embolization of the AVM nidus was used in seven patients (50%) and transcatheter arterial embolization in eight patients (57%). Technical angiographic success was seen in all patients. Five patients (36%) experienced a complete response to treatment, whereas eight (57%) experienced a partial response. Seven patients (50%) required further procedures for residual symptoms. CONCLUSIONS: AVMs with a DOV can be successfully treated by a transvenous approach. Percutaneous puncture embolization of the nidus or draining vein and transcatheter arterial embolization may assist in reducing flow.

Direct percutaneous transhepatic portomesenteric venous stenting in management of locally advanced pancreatic cancer.

OBJECTIVE: Pancreatectomy with portal and/or superior mesenteric vein resection remains a controversial procedure because of high complexity and morbidity. Neoadjuvant chemotherapy has been shown to increase resectability of these locally advanced lesions. We aimed to assess the utility and efficacy of direct percutaneous transhepatic portomesenteric venous stenting (THVS) with neoadjuvant chemotherapy in increasing surgical resectability of locally advanced pancreatic carcinoma. METHODS: Forty pancreatic carcinoma patients with tumor thrombus involving the portal vein and superior mesenteric vein were identified. Patients underwent THVS followed by neoadjuvant chemotherapy. Whipple procedure was offered to responders. RESULTS: THVS was attempted in all. The tumor thrombus could not be crossed in 2 patients (95% technical success rate). All patients underwent 3 cycles of neoadjuvant gemcitabine, paclitaxel, and capecitabine. Disease progression was noted in 16 patients and surgery was not offered. Twenty-two patients were explored with intent-to-perform a Whipple procedure. In 7 of these (32%), extensive disease precluding surgical resection was identified and the procedure was abandoned. Whipple procedure without vascular resection was performed successfully in 15 patients (68%). There were no perioperative deaths. Negative vascular margins were noted in 3 patients and negative peripancreatic lymph nodes in 5 patients. Median survival was 17 months (range, 5 to 70 mo). In the stented nonoperative group, median survival was 9 months (range, 3 to 19 mo). The stented and resected group achieved a statistically significant (P=0.0422) survival advantage. CONCLUSIONS: THVS in combination with neoadjuvant chemotherapy can increase tumor resectability and survival in a select group of locally advanced pancreatic cancer patients.

Transarterial treatment of congenital renal arteriovenous fistulas.

OBJECTIVE: Congenital renal arteriovenous fistulas (CRAVF) represent a distinct clinical entity with characteristic hemodynamic and angiographic features. Treatment is warranted given potential for growth with renal and hemodynamic compromise. We report our experience in a rare series of treated symptomatic CRAVFs. METHODS: Over a 10-year period, patients treated for symptomatic CRAVFs (no history of predisposing renal pathology, instrumentation, neoplasm, or trauma) were retrospectively investigated for clinical presentation, imaging features, treatment outcomes, and complications. Technical success included delivery of embolic agent with complete obliteration of fistula. Clinical success included resolution of symptoms and freedom from recurrence and/or reintervention. Renal parenchymal loss was estimated by postembolization angiography and categorized as 0%, <25%, 25%-50%, or >50%. RESULTS: Twenty-five patients were referred with a presumptive diagnosis of intraparenchymal renal artery aneurysms. Of these, 10 had true intrarenal aneurysms, three had angiomyolipomas, and 12 had CRAVFs (mean age, 54; range, 29-71 years; eight women). Presenting symptoms included hematuria (eight gross, eight microscopic), refractory hypertension (diastolic blood pressure ≥ 90 mm Hg despite three or more medications; n = 6), flank pain (n = 8), high-output state (HOS; featuring tachycardia and jugular venous distention; n = 3), and flank bruit (n = 1). Defining angiographic features included a high-flow AVF fed by a single, enlarged intrarenal branch shunting into an aneurismal draining vein, occasionally featuring a calcified rim (four patients). All patients underwent transarterial embolization with coils (n = 5), coils and n-butylcyanoacrylate (n = 3), detachable balloons (n = 2), or Amplatzer plugs (n = 2). Technical success was 100%. Hematuria, tachycardia, jugular venous distension, pain, and bruit resolved in all. Hypertension improved in four of six patients (required less than three medications postembolization). Complications included postembolization syndrome in nine patients. Parenchymal loss was limited to <25% and observed in five patients without development of acute kidney injury or worsening hypertension. There were no recurrences or reinterventions at a mean follow-up of 55 months (range, 5-96 months). There was one death at 8 years follow-up from intercurrent coronary disease in a patient without high-output state. CONCLUSIONS: With greater awareness and accurate diagnosis, effective and durable transarterial treatment of CRAVFs can be safely performed.

Interventional management of high-flow vascular malformations.

High-flow vascular malformations are among the most challenging lesions in the field of interventional radiology. For an optimal long-term result, the clinician must have a full understanding of the types of lesions, their natural history, appropriate diagnostic studies, indications for treatment, and all the treatment options, including surgery, embolization, laser, and pharmacotherapy. Surgery should, in general, be used primarily for lesions that are completely resectable or are so bulky that embolization would not provide a satisfactory result. Embolization techniques are directed at elimination of the nidus of the lesion, using a variety of penetrating embolic agents both by direct puncture and transcatheter approaches. This paper reviews the principles and techniques primarily involving embolization for lesions occurring in various parts of the body, emphasizing the lessons learned in treating more than 2000 patients over a 30-year period.

Staged endovascular and surgical treatment of slow-flow vulvar venous malformations.

OBJECTIVE: The objective of the study was to report our experience in a rare series of treated symptomatic slow-flow vulvar venous malformations (VVMs) using a staged, multidisciplinary approach. STUDY DESIGN: Consecutive patients with symptomatic lesions treated over a 7 year period (2005-2012) were followed up for technical success, resolution of symptoms, aesthetic outcomes, and complications. Direct endovenous sclerotherapy (DEVS) using sodium tetradecyl sulfate (STS) foam was performed in all patients under ultrasound and contrast-enhanced fluoroscopic guidance. Surgical excision and layered primary closure was performed within 24 hours after the last DEVS session. RESULTS: Eleven patients (mean age, 25 years; range, 4-43 years) were treated. Presenting symptoms included pain (n = 11), soft tissue swelling (n = 11), local heaviness (n = 11), dyspareunia (n = 2), and dysmenorrhea (n = 2). Most were isolated lesions (n = 8). There were 2 cases of Klippel-Trénaunay syndrome and 1 case of Maffucci syndrome. The latter required Nd:YAG laser photocoagulation prior to sclerotherapy. On average, approximately 3 DEVS sessions were required prior to surgical excision (range, 1-6). Mean estimated surgical blood loss was 130 mL (range, 20-400 mL). Mean follow-up was 23 months (range, 3-55 months). Elimination of pain and soft tissue redundancy was achieved in all patients with satisfactory aesthetic outcomes. All patients experienced minor pain and swelling after DEVS. Following surgical excision, there was 1 case of hematoma and wound dehiscence requiring surgical evacuation. No other reinterventions, endovascular or surgical, were required. CONCLUSION: VVMs require increased awareness and appropriate preoperative evaluation for proper identification and treatment. A multidisciplinary approach can provide improvement in clinical signs and symptoms with satisfactory cosmesis and minimal complications.

Endovascular palliation of multivessel blowout syndrome in the setting of a nonresectable neck sarcoma.

Carotid blowout syndrome is a rare life-threatening complication of head and neck malignancy. Current literature has focused exclusively on the carotid system and associated branches. We present a unique case of multivessel blowout in the setting of a large nonresectable neck sarcoma requiring various endovascular techniques for palliation.

Massive and submassive pulmonary embolism: experience with an algorithm for catheter-directed mechanical thrombectomy.

BACKGROUND: The role of catheter-directed mechanical thrombectomy (CDMT) for the treatment of massive pulmonary embolism (MPE) and submassive pulmonary embolism (SMPE) is not clearly defined. We report our experience with an algorithm for CDMT as a primary treatment in patients with MPE and SMPE. METHODS: We retrospectively reviewed our experience in treating MPE and SMPE in consecutive patients over a 2-year period (2008-2010). Patients with computed tomography angiography evidence of saddle, main branch, or ≥2 lobar pulmonary emboli in the setting of hypoxia, tachycardia, echocardiographic right heart strain, and/or cardiogenic shock underwent AngioJet CDMT, with or without adjunctive thrombolytic power-pulse spray. Outcomes, including angiographic success, clinical improvement, complications, and survival to discharge, were evaluated. RESULTS: Fifteen patients (8 men, 7 women; 14 SMPE, 1 SMPE) with a mean age of 59 years (range: 35-90 years) were treated for heart strain (100%), tachycardia (67%), hypoxia (67%), and cardiogenic shock (7%). Ten patients (67%) also received Alteplase power-pulse spray. Resolution of symptoms and improvement in heart strain were achieved in all patients. There were no in-hospital mortalities. Complications occurred in 3 patients (20%), including 2 patients with acute tubular necrosis and 1 patient with an intraoperative cardiac arrest. Average hospitalization was 9 days (range: 4-26 days). All patients were discharged on full anticoagulation. None required supplemental oxygen at discharge. CONCLUSION: CDMT as primary treatment of MPE and SMPE has a high rate of technical and clinical success in a high-risk patient population. Experience and strict patient selection criteria may improve therapeutic outcomes.

Endoleak management following endovascular aneurysm repair.

Endoleaks continue to be a challenge in the endovascular approach to aneurysm repair, both in the abdominal and thoracic aorta. Some of these leaks are related to anatomic factors and patient selection, others are device related, and some (especially type II leaks) appear intrinsic to the endovascular approach. Certain endoleaks require treatment as soon as they are detected due to continued pressurization of the aneurysm sac, while the need for treatment of others remains controversial. Using endovascular techniques, the vast majority of these problems can be successfully addressed without the need for open surgery. This paper reviews our 14 year experience in the management of endoleaks and summarizes our current approach to these patients.

Is endovascular therapy the preferred treatment for all visceral artery aneurysms?

Endovascular intervention can provide an alternative method of treatment for visceral artery aneurysms. We conducted a retrospective review of all patients with visceral artery aneurysms at a single university medical center from 1990 to 2003, focusing on the outcome of endovascular therapy. Sixty-five patients with visceral artery aneurysms were identified: 39 splenic (SAA), 13 renal, seven celiac, three superior mesenteric (SMA), and three hepatic. Eleven patients (16.9%) had symptoms attributable to their aneurysms, which included a total of four ruptures (6.2%): three splenic and one hepatic. Management consisted of 18 (27.7%) endovascular interventions, nine (13.9%) open surgical repairs, and 38 (58.5%) observations. Mean aneurysm diameter for patients treated expectantly was significantly less than for those who underwent intervention (p = 0.001). Endovascular interventions included 15 (83.3%) embolizations (11 SAA, three renal, one hepatic) and three (16.7%) stent grafts (two SMA, one renal). The initial technical success rate of the endovascular procedures was 94.4% (17/18). However, there were four patients (22.2%) with major endovascular procedure-related complications: one late recurrence requiring open surgical repair, two large symptomatic splenic infarcts, and one episode of severe pancreatitis. These four patients had distal splenic artery aneurysms at or adjacent to the splenic hilum. There were no endovascular procedure-related deaths. Reasons for performing open surgical repair included three SAA ruptures diagnosed at laparotomy and complex anatomy not amenable to endovascular intervention (six patients). One surgical patient had a postoperative small bowel obstruction treated nonoperatively; and there was one perioperative death in a patient operated on emergently for rupture. Endovascular management of visceral artery aneurysms is a reasonable alternative to open surgical repair in carefully selected patients. Individual anatomic considerations play an important role in determining the best treatment strategy if intervention is warranted. However, four of 11 (36.4%) patients with distal splenic artery aneurysms treated with endovascular embolization developed major complications. Based on our experience, traditional surgical treatment of SAA with repair or ligation and concomitant splenectomy when necessary may be preferred in these cases.

The use of cyanoacrylate adhesives in the management of congenital vascular malformations.

This article outlines the use of liquid acrylic adhesives in the management of congenital vascular malformations. Specifically, the chemical features of cyanoacrylates, including the physical and chemical properties, exovascular use of cyanoacrylates, and the techniques for use of these agents, are discussed.

Transcatheter embolization of extremity vascular malformations: the long-term success of multiple interventions.

Vascular malformations of the extremities present a difficult therapeutic challenge. Ligation of feeding vessels may lead to tissue necrosis and limb loss and can make subsequent attempts at transcatheter therapy impossible. The purpose of this study was to review our results with transcatheter embolization therapy in symptomatic vascular malformations in the upper and lower extremities in 50 patients. A retrospective review was conducted of a computerized database of all patients undergoing transcatheter therapy of peripheral vascular malformations at our institution. The mean age of the patients was 22 years (range 1-51 years), and 34% were male. The most common presenting symptoms included pain (80%), swelling (68%), ulceration or distal ischemia (18%), and hemorrhage (6%). Previous unsuccessful surgical treatment or embolization had been performed in 24% and 18% of patients, respectively. Predominantly venous lesions were treated by sclerotherapy with injection of ethanol. Arteriovenous and arterial lesions were treated by embolization via the arterial branch feeding vessels with cyanoacrylate. The most common vessels involved and treated were branches of the profunda femoris and tibial arteries (83% of lower extremity lesions), and branches of the brachial and radial arteries (82% of upper extremity lesions). Patients required a mean of 1.6 embolization procedures (range 1-5) over a mean period of 57 months. Sixteen patients (32%) underwent more than one embolization procedure. Of these, one was a planned staged procedure and 15 were performed secondary to residual or recurrent symptoms. Adjunctive surgical procedures were performed subsequent to embolization in three cases (6%). Ninety-two percent of patients remained asymptomatic or improved at a mean follow-up of 56 months. There was one case of limb loss (2%). Diffuse extremity vascular malformations are difficult to eradicate completely and recurrences are common. Although patients may require multiple embolization procedures and occasional adjunctive surgical resection, directed transcatheter embolization should be the treatment of choice for symptomatic extremity vascular malformations.

Two-station bolus-chase MR angiography with a stationary table: a simple alternative to automated-table techniques.

OBJECTIVE: Our purpose was to evaluate a simple, two-station, bolus-chase, peripheral MR angiography technique that relies on manual patient translation using a plastic patient-transfer board. SUBJECTS AND METHODS: Twenty patients successfully completed both lower extremity MR angiography and digital subtraction angiography within a 3-month period. For MR angiography, patients were placed on the scanner table on a standard plastic patient-transfer board. We performed unenhanced and contrast-enhanced imaging at the level of the pelvis using a three-dimensional gradient-echo sequence (TR range/TE range, 3.8-4.6/1.3-1.8; flip angle range, 25-40 degrees ). Then patients were quickly pulled 350-400 mm using the transfer-board handles, and two subsequent acquisitions were obtained at the level of the thighs. For each modality, two radiologists who were unaware of correlative imaging results retrospectively scored all vessel segments as either greater than or equal to 50% stenosis or less than 50% stenosis, and interobserver agreement was determined. Using digital subtraction angiography as the standard of reference, we used consensus data to compute MR angiography sensitivity and specificity. RESULTS: In the 261 vessel segments considered, MR angiography had a sensitivity of 75% (12/16) and a specificity of 98% (94/96) for the detection of stenosis greater than or equal to 50% from the aorta through the common femoral arteries. For the superficial and profunda femoral arteries through the popliteal arteries, these values were 97% (31/32) and 94% (34/36), respectively. MR angiography interobserver agreement for detection of stenosis was good (kappa = 0.68) for the aorta through the common femoral arteries and excellent (kappa = 0.88) for the superficial and profunda femoral arteries through the popliteal arteries. These values were comparable to those found for digital subtraction angiography (kappa = 0.67 and kappa = 0.88, respectively). CONCLUSION: Stationary-table MR angiography is a useful, simple strategy for lower extremity angiography in centers without a moving table.

CT differentiation of large exophytic renal angiomyolipomas and perirenal liposarcomas.

OBJECTIVE: The purpose of our study was to describe the imaging findings and CT characteristics that lead to accurate distinction of large exophytic renal angiomyolipomas from retroperitoneal perirenal liposarcomas, which at times can be confused on imaging studies and even at pathologic examination. MATERIALS AND METHODS: We retrospectively analyzed CT images of 15 large exophytic renal angiomyolipomas and 12 well-differentiated perirenal liposarcomas. Pathologic correlation was available for six of 15 angiomyolipomas and all of the liposarcomas. All examinations were evaluated for lesion size, renal parenchymal defect, enlarged vessels, kidney displacement, lesion encapsulation or margination, associated hemorrhage, and additional angiomyolipomas. The records of patients with tuberous sclerosis or the forme fruste of that condition were excluded from the study. RESULTS: The average size of the angiomyolipomas was 14 x 10 cm. They showed a renal parenchymal defect (n = 15), enlarged vessels (n = 12), renal displacement (n = 14), good margination without a distinct capsule (n = 14), hemorrhage (n = 1), and additional (one or two) angiomyolipomas (n = 4). The average size of the liposarcomas was 18 x 11.6 cm. They showed enlarged vessels (n = 3), renal displacement (n = 11), and encapsulation (n = 4); none showed a renal parenchymal defect, hemorrhage, or associated angiomyolipomas. CONCLUSION: Although large exophytic angiomyolipomas and well-differentiated retroperitoneal liposarcomas may have similar appearances on imaging, careful evaluation for a defect in the renal parenchyma combined with the presence of enlarged vessels in angiomyolipomas should enable accurate differentiation in almost all cases. Achieving an accurate diagnosis can have a significant impact on patient treatment.

Are type II (branch vessel) endoleaks really benign?

The natural history and clinical significance of type II or branch vessel endoleaks following endovascular aortic aneurysm (AAA) repair remain unclear. Some investigators have suggested that these endoleaks have a benign course and outcome and that they can be safely observed. The purpose of this study was to document the natural history and outcome of all type II endoleaks that have occurred following endovascular AAA repair at our institution. A review of a prospectively compiled database of all endovascular AAA repairs performed at our institution was performed. From this review, we determined that type II endoleaks appear to have a relatively benign course, with a reasonable chance of spontaneously sealing within a 2-year period. No cases of rupture or aneurysm enlargement were documented in patients with open type II leaks. However, almost one-third of the patients did not manifest a type II leak until after their initial CT scan. The implications of such a "delayed" leak are unclear. Careful follow-up remains mandatory in patients with type II endoleaks to better define outcome.