New videodensitometric method for measuring renal artery blood flow at routine arteriography: validation in the canine model.

A contrast medium was injected in the aortic arch and selectively in a renal artery to estimate the renal blood flow as a percentage of the cardiac output by the videodensitometric (VD) method. Twenty-six paired VD measurements in four mongrel dogs were obtained and the results compared to electromagnetic (EM) flow readings from the aortic arch and a renal artery. The relative renal blood flow estimated by the VD method averaged 9.1% and correlated with the EM flow average of 9.6% with r = 0.96. Previous in vitro investigations of relative flow in a model have now been validated in vivo. These results suggest that videodensitometry could be a clinical tool for measuring renal blood flow in conjunction with routine arteriography.

Assessment of peripheral blood flow in man by video dilution technique: a preliminary report.

Video dilution technique is now available for clinical use in evaluating patients with peripheral vascular disease. The measurements can easily be performed in any modern angiographic suite. The only additional equipment required is a videodensitometer, video tape recorder, and a strip chart recorded. The new technique has been developed and tested in a hydrodynamic model and compared to volumetric flows. Further, the video dilution technique has been compared to electromagnetic flow readings using a canine model to measure the cerebral, renal, splanchnic, and extremity circulation and has proven to be extremely accurate (n = 389; r = 0.99). By applying the technique to patients with peripheral vascular disease, it is possible to evaluate the hemodynamic significance of stenotic lesions and arteriovenous shunts. Other uses of video dilution technique include evaluating the effects of vasoactive drugs and the adequacy of transluminal angioplasty.

Assessment of cerebral blood flow in man by video dilution technique: a preliminary report.

Video dilution technique (VDT) is currently performed in conjunction with routine cerebral angiography to determine carotid blood flow in humans. Preliminary results indicate that the blood flows (as a percentage of cardial output) of the common, internal, and external carotid arteries are 8.5%, 5.5%, and 3.0%, respectively (SD less than 1%). In contradistinction to previous techniques, VDT provides a safe and highly accurate method of determining carotid blood flow in human subjects. The usefulness of this technique in normal and pathologic states is discussed.

Bronchial blood flow measured by video dilution technique in sheep.

Bronchial blood flow was studied with the video dilution technique (VDT) in seven sheep. All animals were anesthetized (thiamylal and halothane) and ventilated. A videodensitometer and a videotape replay of the fluoroscopic image of dye moving through the common bronchial artery were used to construct dye mass vs. time curves. The areas under the curves were inversely proportional to flow in the bronchoesophageal artery, the site of dye injection. At thoracotomy, an electromagnetic flow probe (EMFP) was placed on the common bronchial artery (the major branch of the bronchoesophageal artery) to measure blood flow changes simultaneously by EMFP and by VDT. These two methods of measurement of blood flow to the airways were compared to validate the use of VDT in this circulation. Common bronchial artery blood flow was increased by injection of radiocontrast dye into the fluoroscopically positioned bronchoesophageal artery catheter causing hyperosmotically induced hyperemia. In 160 simultaneous measurements in five sheep, the percent change in flow as measured by EMFP and VDT correlated closely (r = 0.96). When flow changed because of spontaneous aortic pressure changes or pharmacologic intervention (28 simultaneous measurements in five sheep), the percent change in flow by EMFP and VDT also correlated well (r = 0.98). Bronchial blood flow changes in sheep can be measured accurately using the video dilution technique.

Hydrogel embolic agents. Theory and practice of adding radio-opacity.

RATIONALE AND OBJECTIVES: Spheres of hydrogel have been developed as embolic material with the ability to incorporate radio-opaque materials. To optimize particle design for radiographic or fluoroscopic visualization, we have examined the theoretical determinants of particle contrast. In addition, loaded hydrogel particles were tested in a rabbit model. METHODS: Computer simulations of particle subject contrast were examined regarding particle composition, particle size, patient thickness, and x-ray beam kilovoltage. Embolizations in the rabbit kidney were used to test the practical aspects of the materials. RESULTS: Tantalum and tungsten offer some theoretical and practical advantages over other materials. With this particular hydrogel preparation, contrast material loading was limited to 20% of the volume as loaded contrast agent. The soft particles passed through catheters as small as 3 French; they were usually injected as a suspension of saline/contrast material. Tantalum/hydrogel particles as large as 2 mm could be forced through the 140 cm/3-Fr catheter with a guide wire. CONCLUSIONS: Radio-opacity of embolic material should add an element of control in embolization procedures that is lacking with the current agents. The heavy metals, tungsten and tantalum, are suitable additives for radiopaque material for hydrogel emboli. The input relationship appears predictable with computer monitoring techniques. Initial results in a study of these radiopaque particles are very encouraging. Further studies are underway to evaluate the long-term effects in renal and hepatic circulations.

Partial splenic embolization guided by blood flow measurements.

The author used blood flow measurements to guide partial splenic embolization procedures in five patients. The measurements were obtained by time density analysis of contrast medium injections in the splenic artery using digital subtraction angiographic techniques and modified software. The blood flow measurements demonstrated blood flow changes occurring as a result of the embolization. The embolization procedures continued until the blood flow in the splenic artery had been reduced to 50% of its original value. The blood flow measurements appear to predict the amount of parenchymal reduction achieved by embolization and show promise as a method of monitoring these procedures.

Role of bronchial artery embolization in the management of hemoptysis.

OBJECTIVE: To assess the modern morbidity of hemoptysis and the contribution of therapeutic bronchial artery embolization to its management. METHODS: Medical record review of patients admitted for the treatment of hemoptysis from January 1991 to November 1995 and of patients who had therapeutic bronchial artery embolization from June 1986 to August 1995. Hemoptysis was labeled major or minor. RESULTS: A total of 138 patients were admitted with hemoptysis, 31 with major and 107 with minor hemoptysis. No emergency pulmonary resections were required. Mean follow-up was 13.5 months. Mortality was 29.7% (41/138) but was caused by bronchial bleeding in only 4.3% (6/138). Twenty-six patients underwent therapeutic bronchial artery embolization (mean follow-up [range], 14 months [0.3-69.0 months]). The initial success rate (no further bleeding during the initial admission) was 85% (22/26). The long-term success rate (no further bleeding during follow-up) was 58% (15/26). Only 2 patients with therapeutic bronchial artery embolization died of further hemoptysis. CONCLUSIONS: Hemoptysis signals life-threatening diseases. Therapeutic bronchial artery embolization is a good treatment adjunct to control bronchial bleeding and reduces the need for high-risk emergency lung resections.

Video dilution technique. An accurate measure of blood flow during routine arteriography.

The video dilution technique for measuring blood flow consists of electronically and mathematically processing video-taped selective arteriograms to measure the flow in selectively catheterized arteries and to express this flow as a fraction of the flow in any reference artery. Flows were measured by video dilution and an electromagnetic flowmeter in ten dogs; the correlations were excellent. Video dilution flows were also measured in 105 patients. The technique is accurate, simple, and adds no risk to routine selective arteriography.

Bilateral ureteropelvic junction avulsion after blunt abdominal trauma.

Ureteral pelvic junction avulsion can occur after deceleration injury. A case of this type of injury is presented herein, as well as a review of the literature.

Carotid blood flow in man determined by video dilution technique: 1. Theory, procedure, and normal values.

The blood flows in the common, internal, and external carotid arteries were determined as a percentage of the cardiac output by video dilution technique in 20 normal subjects during routine angiography. Nine women and 11 men, ages 19-63 years, displayed a mean flow in the common carotid of 8.5% (SD +/- 0.9%; n = 40); internal carotid, 5.3% (SD +/- 1.0%; n = 24); and external carotid, 3.2% (SD +/- 0.4%; n = 24). Relative flow is calculated by a modification of the Stewart-Hamilton principle. The technique is fast, simple, highly accurate, and avoids the errors connected with previous videodensitometric mean transit time techniques. The method can be used in routine angiography without prolonging the catheterization procedure or adding to the patient's risk or cost.

Carotid blood flow in man determined by video dilution technique: II. Vascular abnormalities.

Carotid blood flows were evaluated in 31 individuals with vascular abnormalities using the video dilution technique. In patients with stenoses, angiographically estimated at 70%, blood flow was usually, but not always, measured less than normal. The technique proved to be useful in the evaluation of the efficiency of collateral arterial pathways and in the evaluation of superficial temporal-middle cerebral arterial bypass grafts. It was also helpful in estimating contralateral increase in arterial flows with cross compression techniques for the preoperative evaluation of patients subjected to carotid sacrifice. In a limited number of patients video dilution flows correlated with the degree or proximal arterial spasm and were useful in the preoperative study of these patients. The demonstration of flow abnormalities in patient with seizure disorders may be useful in the medical and surgical management of these individuals.

Selective embolization for control of gastrointestinal hemorrhage.

Transcatheter embolization using Gelfoam plugs or autologous clot is an alternative or adjunct to the conventional management of gastrointestinal hemorrhage. During a 12 month period we successfully treated 10 patients who had massive gastrointestinal hemorrhage with selective embolization; 6 patients had upper gastrointestinal hemorrhage and 4 had bleeding from the colon. Most of these patients were critically ill and were poor surgical candidates. Hemorrhage was controlled by selective catheterization of the bleeding vessel, followed by injection of Gelfoam pledgets. Since the procedure was accomplished with ease and prolonged hemostasis obtained, we recommend it for gastrointestinal hemorrhage, especially in patients who are poor surgical risks or are unresponsive to vasopressin infusion, or both. Operative intervention for the primary disease could subsequently be performed electively, if necessary, days or weeks after transcatheter embolization.

Indirect computed tomography lymphography using iodinated nanoparticles to detect cancerous lymph nodes in a cutaneous melanoma model.

RATIONALE AND OBJECTIVES: To evaluate differences in contrast uptake in normal and cancerous lymph nodes on indirect computed tomography (CT) in swine, we conducted lymphographic examinations after subcutaneous injection of a lymphotropic iodinated nanoparticle suspension. METHODS: Perilesional subcutaneous contrast injections (2 ml per lesion) of a 15% wt/vol iodinated nanoparticle suspension were made in immature Sinclair miniature swine (n = 5) with cutaneous melanomas. Average attenuation, iodine concentration, node volume, and total iodine uptake were estimated on the CT scans for each opacified lymph node 24 hr after injection. Nodes were classified as normal or cancerous microscopically, and the percentage of tumor replacement was estimated in cancerous nodes. RESULTS: Average attenuation and iodine concentration were higher in normal nodes, and total iodine uptake was higher in cancerous nodes with greater than 25% replacement (p < .05). Architectural alterations in opacified cancerous nodes included medullary filling defects, expansile cortical lesions, and disruption of corticomedullary junctions. CONCLUSION: Quantitative and qualitative differences in iodinated nanoparticle enhancement characteristics are useful in distinguishing between normal and cancerous lymph nodes on indirect CT lymphography examinations.

Superior mesenteric artery vasoactivity in hyperlipidemic Watanabe rabbits versus normal lipidemic New Zealand controls.

Recent in vitro studies on isolated coronary and mesenteric arteries have shown that hyperlipidemia appears to hypersensitize the vascular arterial smooth muscle to drugs such as ergonovine and that this increased contractility seems to be mediated by a serotinergic mechanism. This results in vasospasm with exposure to certain vasoactive drugs such as serotonin or norepinephrine. However, in vivo quantification of this observed phenomenon has not been done. In the present study we used Watanabe hereditary hyperlipidemic (WHHL) rabbits (cholesterol level 459 +/- 216 mg/dL) and the normal lipidemic New Zealand white (NZW) rabbit (cholesterol level 35 +/- 19) as a control in the study of hyperlipidemia and blood flow changes in response to various vasoactive drugs. Blood flow measurements were made by the video dilution technique (VDT) following catheterization of the superior mesenteric artery. The serotinergic vasoactive drug ergonovine maleate was injected into the superior mesenteric artery at low dose (0.002) mg/kg) and high dose (0.004 mg/kg). A significant decrease (p less than .05) in blood flow was observed in response to high-dose ergonovine maleate in WHHL rabbits compared to the NZW rabbits. This in vivo experiment confirms the in vitro studies showing that hyperlipidemia sensitizes mesenteric arteries in the presence of serotinergic stimuli. The vasodilators verapamil hydrochloride and calcitonin gene-related peptide (CGRP) injected into the superior mesenteric artery caused a marked increase in flow in both the WHHL and the normal lipidemic NZW rabbits. This model can be used in the assessment of superior mesenteric artery ischemia and its reversal.

Arteriography before needle puncture or renal hilar lesions.

We report on 2 patients with cystic-appearing lesions in the renal hilus that were detected on urography. In 1 case an ultrasound study confirmed a cystic mass but an arteriogram revealed a renal artery aneurysm. The arteriogram before the contemplated puncture of the renal hilar mass prevented an inadvertent puncture. The information about the arterial anatomy helped preoperative planning, which resulted in successful repair of the aneurysm by microdissection and autotransplantation.

Vasodilator response in the lower extremity induced by contrast medium. I Canine model.

The vasodilator response induced by injections of contrast medium was observed in 11 dogs by electromagnetic flow technique. The experiments were performed to further understand video dilution technique (VDT) measurements in patients with arterial obstructive disease. Responses were observed with regard to the contrast dose relationship, time to peak flow, and abnormal flow produced up to 4 ml caused increasing magnitude of peak flow. The time to peak flow was relatively constant for all doses. Mechanical constrictions depressed th peak flow magnitude but did not affect the time to peak. Emboli produced both depression of the flow magnitude and a delay in time to peak flow. The data suggest that the VDT vasodilatory response curves obtained in patients should correlate with the degree of obstructive disease and delay in the peak flow implies outflow disease.

Symptomatic spleno-mesenteric-portal venous thrombosis: recanalization and reconstruction with endovascular stents.

PURPOSE: To evaluate the safety and efficacy of portal reconstruction in patients with symptomatic spleno-mesenteric-portal venous thrombosis. MATERIALS AND METHODS: Portal reconstruction was attempted in 21 patients (seven women, 14 men; mean age, 53.6 years +/- 15.2) with chronic thrombosis of the portal vein alone (n = 8), splenic vein alone (n = 3), or portal, mesenteric, and splenic veins (n = 10). Indications for the procedure were bleeding varices (n = 15), ascites (n = 2), hypersplenism (n = 2), and enteropathy (n = 2). Sixteen procedures were started transhepatically and of these seven were converted to a transjugular intrahepatic portosystemic shunt (TIPS) after successful recanalization of the thrombosed vein. In six patients reconstructions were performed using an intrahepatic portal vein as outflow. Five procedures were performed primarily as TIPS. Wallstents dilated to 7-10 mm were used for reconstruction. The mean follow-up period was 15.2 months +/- 15.9. RESULTS: Technical success of portal reconstruction was 85.7% (18 of 21). Thirty-day mortality was 14.3% (three of 21) but was not procedural related. The cumulative rates of survival, primary patency, and palliation at 43 months of follow-up were 61.2% +/- 13.5%, 63.5% +/- 15.3%, and 31.7% +/- 15.7%, respectively. Secondary patency was 79.1% +/- 13.8%. The only predictor of mortality was the presence of liver disease (P = .001, Cox regression). CONCLUSION: Portal reconstruction is a safe and effective treatment option for patients with symptomatic chronic portal thrombosis. Liver disease predisposes to a higher mortality.

Spontaneous rupture of an iliac artery aneurysm into a ureter: a case report and review of the literature.

A case of massive hematuria from spontaneous rupture of an iliac artery aneurysm into a ureter is reported. The vascular causes for gross hematuria are reviewed and the various arterial aneurysms are discussed. The need to consider vascular abnormalities when dealing with massive hematuria is emphasized.

Renal flow response to contrast medium measured by video dilution technique.

The renal blood flow response following a sequence of small contrast medium injections was analysed in normal dogs and normal human subjects by video dilution technique. The results indicate that the video dilution technique offers an excellent opportunity in detecting abnormal flow responses in patients with renal hypertension.