Role of angiography in the detection of aortic branch vessel injury after blunt thoracic trauma.

PURPOSE: The occurrence of aortic arch branch vessel injury as an isolated occurrence or in association with aortic injury after blunt chest trauma has not been emphasized in the literature. The imaging evaluation is also controversial. METHODS: We reviewed thoracic aortograms of 166 patients examined at our institution from May 1995 to May 1999 performed after blunt thoracic trauma. We evaluated the aortograms for aortic and arch branch vessel injuries. Twenty-four injuries were detected and all patients had either a wide mediastinum demonstrated on plain radiographs (22 patients) or mechanism of injury conducive to aortic injury. RESULTS: Of the 166 patients, 24 (14%; 16 men, 8 women; mean age, 50 years) had aortic or arch branch vessel injuries. Isolated aortic injury occurred in 15 (9%) of 166 patients. Branch vessel injury occurred in 9 (5%) of 166 patients; seven patients (10 branch vessels) had isolated branch vessel injury and two patients (three branch vessels) had branch vessel injury associated with aortic injury. The injured branch vessels were brachiocephalic artery (four), left common carotid artery (four), left subclavian artery (three), right internal mammary artery (one), and left vertebral artery (one). The types of branch vessel injuries included intimal tears (nine vessels; 69%), and transection causing a pseudoaneurysm (four vessels; 31%). Revised Trauma Scores in patients with branch vessel injuries were 12 in seven patients and 11 and 4 in one each. CONCLUSION: We emphasize the angiographic findings in these patients that can at times be quite subtle. Awareness of the incidence of such injuries either in isolation or associated with aortic injury has implications regarding evaluation of this patient population with less invasive techniques such as CT or transesophageal echocardiography.

Gallbladder stones: imaging and intervention.

Imaging of the gallbladder for cholelithiasis and its complications has changed dramatically in recent decades along with expansion of interventional techniques related to the disease. Ultrasonography (US) is the method of choice for detection of gallstones. The characteristic US findings of gallstones are a highly reflective echo from the anterior surface of the gallstone, mobility of the gallstone on repositioning the patient, and marked posterior acoustic shadowing. Oral cholecystography remains an excellent method of gallstone detection, but its role has been limited due to the advantages of US. Most people with cholelithiasis will not experience symptoms or complications related to gallstones. When biliary colic does occur, it is typically caused by transient obstruction of the cystic duct by a stone. The primary imaging modality in suspected acute calculous cholecystitis is usually US or cholescintigraphy. Detection of gallstones alone does not permit a diagnosis of acute cholecystitis; however, secondary US findings provide more specific information. In detection of choledocholithiasis, endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography are superior to US. In certain clinical settings, interventional radiologic procedures have become an important alternative to surgery in the treatment of gallstones and their complications; techniques include percutaneous cholecystostomy and gallstone removal.

Experimental and computational flow evaluation of coronary stents.

Local flow alterations created by a metallic stent in a simulated coronary artery were studied to compare the hemodynamic effects of two different stent geometries. Dye injection flow visualization and computational fluid dynamics were used. Resting and exercise conditions were studied. Flow visualization using the dye injection method provided a qualitative picture of stent hemodynamics while the computational approach provided detailed quantitative information on the flow next to the vessel wall near the intersections of stent wires. Dye injection visualization revealed that more dye became entrapped between the wires where the wire spacing was smallest. The dye washout times were shorter under exercise conditions for both wire spacings tested. The computational results showed that stagnation zones were continuous from one wire to the next when the wire spacing was small. Results from greater wire spacing (more than six wire diameters) showed that the stagnation zones were separate for at least part of the cardiac cycle. The sizes of the stagnation zones were larger under exercise conditions, and the largest stagnation zones were observed distal to the stent. These studies demonstrate that stent geometry has a significant effect on local hemodynamics. The observation that fluid stagnation is continuous in stents with wire spacings of less than six wire diameters may provide a criterion for future stent design.

Percutaneous transcatheter renal ablation with absolute ethanol for uncontrolled hypertension or nephrotic syndrome: results in 11 patients with end-stage renal disease.

PURPOSE: Retrospective review of authors' experience with percutaneous transcatheter renal ablation in patients with uncontrolled hypertension and/or nephrotic syndrome. MATERIALS AND METHODS: Between April 1987 and September 1995, renal ablation was performed on 11 patients aged 10 months to 21 years. All patients had end-stage renal disease (ESRD) with uncontrolled hypertension (10 patients) and/or nephrotic syndrome (four patients). Uncontrolled hypertension was defined as diastolic pressure greater than 90 mm Hg despite multidrug antihypertensive therapy. Nephrotic syndrome was defined as proteinuria exceeding 960 mg/m2 per day, serum albumin level less than 3 g/dL, and generalized edema. Embolization was performed with absolute ethanol from a common femoral artery approach. In most cases, a balloon catheter was used to prevent alcohol reflux into the aorta or nontarget renal artery branches, such as the adrenal arteries. Angiographic stasis of contrast material in the renal arteries was the endpoint. RESULTS: All patients experienced a postembolization syndrome of 3-5 days duration, clinically manifested by variable degrees of nausea, vomiting, fever, and pain. Long-term improvement in hypertension was observed in nine patients. Improvement in hypertension was defined as diastolic blood pressure below 90 mm Hg while the patient received the same or fewer antihypertensive medications. The four patients with nephrotic syndrome were cured of their proteinuria and edema. CONCLUSIONS: Transarterial renal ablation with alcohol is efficacious for treatment of uncontrolled hypertension and nephrotic syndrome in patients with ESRD. The morbidity and mortality in our series were less than those reported for surgical nephrectomy.

Overview of traumatic injury of the thoracic aorta.

Traumatic injury of the thoracic aorta is a major clinical concern in patients who sustain deceleration or crush injuries. Several mechanical factors may explain the typical locations of thoracic aortic rupture (aortic isthmus, ascending aorta). Understanding these factors and the pathophysiology involved helps the radiologist to recognize aortic trauma at various imaging examinations. Chest radiography is the initial screening examination, and radiographs are evaluated specifically for signs of mediastinal hematoma, an indication of significant thoracic trauma. The most important of these signs include loss of aortic contour, tracheal deviation, ratio of mediastinal width to chest width, deviation of a nasogastric tube to the right of the T-4 spinous process, and depression of the left main-stem bronchus (> 40 degrees below the horizontal). Computed tomography (CT) is used increasingly when results of chest radiography are equivocal. CT can clearly demonstrate mediastinal hematoma, but this finding is also mimicked by several entities, including atelectatic lung, thymus, and pericardial recesses. Aortography is the standard for diagnosis. Traumatic aortic injury is treated urgently with surgical repair. The rare patient who survives aortic injury without surgery may develop a chronic pseudoaneurysm.

Angioplasty of a coronary artery via the translumbar approach in a patient with severe peripheral vascular disease.

We report on a woman with severe peripheral vascular disease with unstable angina, in which access to the central circulation was not possible from a peripheral route. The translumbar approach was used for coronary angiography and a successful angioplasty of the left circumflex artery.

A method to evaluate the elastic behavior of vascular stents.

PURPOSE: To develop a simple method for determining the elastic behavior of vascular stents. MATERIALS AND METHODS: An experimental apparatus was constructed to determine the elastic behavior of four different vascular stents. Each stent was expanded within an artificial compliant vessel and was subjected to an increasing external pressure. The cross-sectional area of each stent was recorded at incremental changes in pressure. Compliance was estimated from the slope of a linear regression analysis fit to the pressure-area data in the elastic range of deformation. RESULTS: The self-expandable stents were the most compliant, and balloon-expandable stents exhibited the least compliance. The balloon- expandable stents initially deformed in an elastic manner and then yielded irrecoverably at higher pressures. CONCLUSION: A simple method has been devised that allows the elastic behavior of stents to be assessed. Quantification of stent compliance with this method is important as a predictor of stent resistance to compression in vivo.

Effects of vascular stent surface area and hemodynamics on intimal thickening.

PURPOSE: To compare the in vivo response to a new mechanically expandable vascular stent with the response to an existing type of balloon-expandable stent. MATERIALS AND METHODS: Prototype stents were deployed by means of a balloon catheter in the left iliac arteries of four healthy dogs. Palmaz stents were deployed in the contralateral iliac arteries to act as a control, and all stents were explanted after 6 weeks. Arteriography was performed at the time of insertion and before harvest, and pressure gradients were measured across each stent. The stents were then harvested and submitted for histologic examination. RESULTS: The performance of the prototype stent was similar to that of the Palmaz stent with respect to structural integrity, migration, maintenance of intraluminal diameter, ease of deployment, radiopacity, and pressure gradients. Unlike the Palmaz stent, the prototype stent did not foreshorten during expansion. The stents showed a lack of uniformity in terms of the measured luminal area and neointimal accumulation. Neointimal accumulation was more confined to the struts of the prototype stent; the lumen therefore had a fluted appearance. Neointimal accumulation was more broadly distributed around the circumference of the vessel wall of the Palmaz stent. CONCLUSION: In vivo performance of the prototype stent was similar to that of the Palmaz stent. Stent geometry may be an important determinant of neointimal response and resultant long-term patency.

Comparison of penile duplex ultrasonography to pudendal arteriography. Variant penile arterial anatomy affects interpretation of duplex ultrasonography.

RATIONALE AND OBJECTIVES: Duplex ultrasonography is currently used as a noninvasive imaging modality for the functional evaluation of penile blood flow in impotent men. However, the accuracy of this test is controversial. The objective of this study was to determine the sensitivity and specificity of duplex ultrasonography, to assess the ultrasonographic parameters most predictive of arterial disease, and to evaluate the causes of misinterpretation of duplex ultrasound studies. METHODS: Duplex ultrasonography and pudendal arteriography were performed on 42 impotent men during a 4-year prospective study. The predictive power of the following ultrasonographic parameters were analyzed: cavernosal arterial diameter, peak blood flow velocity, and pulsations on real-time ultrasonography. RESULTS: The results of both studies were concordant in 81% of the patients with a 77% sensitivity and 85% specificity for ultrasonography when using arteriography as the gold standard. Arterial pulsations and peak blood flow velocity were most predictive, whereas dilation was not helpful. Variant penile arterial anatomy was present in 83% of the patients and was the most frequent cause of misinterpretation of duplex ultrasonography. CONCLUSION: Duplex ultrasonography is a fairly reliable screening test for arterial disease in impotent men. Visualization of arterial pulsations and measurement of peak blood flow velocity are the best predictors of arterial function. Awareness of the potential arterial anomalies may help reduce misinterpretation of ultrasonography. Arteriography is necessary in any patient being considered for penile arterial surgery because of the high frequency of anatomic variations.

Percutaneous nephrostomy for treatment of intractable hemorrhagic cystitis.

Six patients with severe hemorrhagic cystitis unresponsive to traditional localized therapy were treated with percutaneous nephrostomy for diversion of urine. Bladder hemorrhage ceased in 3 patients, decreased in 2 and was unchanged in 1. In 1 patient with profound thrombocytopenia perirenal hematoma developed as a result of the nephrostomy placement but this complication was self-limited and did not require surgery. Our experience with these 6 patients indicates that nephrostomy diversion is safe and effective in most cases of hemorrhagic cystitis refractory to traditional, nonoperative therapy. Percutaneous urine diversion may obviate the need for surgical urinary diversion in patients who have intractable hemorrhagic cystitis.

Transcatheter embolization of a high-flow congenital intrahepatic arterial-portal venous malformation in an infant.

An intrahepatic arterial-portal venous malformation (APVM) was diagnosed in a 4 1/2-month-old infant with portal hypertension. Visceral angiography showed a large saccular vascular space in the left hepatic lobe with a multiplicity of feeding arteries and drainage into the left portal vein. The lesion was successfully treated by transcatheter embolization following two unsuccessful surgical procedures. Two years later portal vein thrombosis with cavernous transformation was diagnosed, possibly a consequence of the high-flow arterial-portal shunt and its subsequent occlusion. Knowledge of the anatomic differences between this rare congenital APVM and the more commonly occurring arterial-portal fistula is crucial in planning effective transcatheter embolotherapy or surgery for these lesions.

Peripheral arterial occlusive disease: prospective comparison of MR angiography and color duplex US with conventional angiography.

Conventional angiography, two-dimensional inflow magnetic resonance (MR) angiography, and color duplex ultrasound (US) were performed on 12 patients in a blinded, prospective study. The ability to grade arterial lesions and plan revascularization interventions were compared. Arterial lesions were categorized as nonsignificant (0%-49% diameter reduction) or significant (50%-100% diameter reduction). Determination of nonsignificant and significant lesions with MR angiography was in agreement with that at conventional angiography in 100 of 140 lesions (71%). Agreement between results of conventional angiography and color duplex US occurred with 114 of 123 infrainguinal lesions (93%). Twenty-one vascular interventions were planned by using conventional angiography; there was agreement with color duplex US in 11 cases and MR angiography in five. Color duplex US performed well in the assessment of infrainguinal disease but was limited in the evaluation of iliac segments because of nonvisualization. The iliac region was visualized in more patients with MR angiography than with color duplex US, but image quality with MR angiography was inconsistent. Strategies to improve MR angiography of the peripheral vasculature merit further study.

Urokinase infusion: feasibility of monitoring for complications in a non-intensive care setting.

In an effort to more effectively use critical care facilities and to reduce costs, during a 2 1/2-year period, the condition of 32 patients who received 37 local intraarterial urokinase (UK) infusions was monitored in a non-intensive care unit (ICU) setting. Techniques of infusion, mean total dose of lytic agent used (1.7 million IU), and mean duration of infusion (22 hours) were similar to those reported previously in series of patients monitored in the ICU. Complete lysis (no angiographically detectable residual clot within the treated segment) was achieved in 28 of 37 infusions (76%). Major complications occurred during two infusions (5.4%). In 33 of the 37 cases, systemic heparin was administered during UK infusion. No cases of pericatheter thrombosis were encountered. At the authors' institution, patients can be safely monitored during local UK infusion in a non-ICU setting without compromising effectiveness of therapy. This approach has resulted in enhanced cost-effectiveness of thrombolytic therapy and more effective use of critical care facilities.

Anomalous origin of bronchial arteries: potential pitfall of embolotherapy for hemoptysis.

Bronchial artery embolization was performed in two patients with anomalous origins of the bronchial artery. In one patient, the anomalous bronchial artery originated from the convex surface of the aortic arch between the origins of the brachiocephalic and left carotid arteries, while in the other, it originated from the internal mammary artery. Anomalous bronchial arteries represent a potential pitfall during bronchial artery embolization. Radiologists involved in embolotherapy for hemoptysis should therefore be alerted to the possible presence of anomalous bronchial arteries, especially when significant bronchial artery supply to areas of abnormal pulmonary parenchyma is not demonstrated at a catheter search or aortography of the descending aorta. In these instances, arch aortography should be performed to identify anomalous origins of the bronchial arteries or other nonbronchial systemic collateral vessels.

Transcatheter thrombosis of a leaking saccular aneurysm of the main renal artery with preservation of renal blood flow.

Percutaneous techniques have been used in the treatment of aneurysms and pseudoaneurysms in a variety of anatomic locations, including the kidney. An elderly patient with a leaking saccular aneurysm of the main left renal artery was considered a poor operative risk. We were able to embolize and thrombose the aneurysm selectively by using a combination of coil springs, guidewire, thrombin, and bucrylate without occluding the renal artery.