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PubMed2004

Preoperative embolization of intracranial meningiomas with Embosphere microspheres.

BACKGROUND: To reduce intraoperative bleeding and to facilitate surgery by inducing tumor softening, a preoperative embolization of meningiomas is commonly recommended. PATIENTS AND METHODS: We report on our experience with non-resorbable microspheres (Embosphere) in the preoperative endovascular embolization of 17 intracranial meningiomas. After adding contrast media to the particles sized 40-500 micron, the embolization process was followed under fluoroscopy. There was a good passage of microcatheters if high concentrations of particles were avoided. RESULTS: The obstruction of the tumor feeders by particles was accompanied by a regression of tumor blush in DSA. CT controls showed a diminished contrast accumulation of the tumors already 1-2 days after embolization. Histologically, Embosphere microspheres were easy detectable with all commonly used staining methods. Embolization triggered, microscopically detectable necrosis was found in 77 % of the tumors. The mean interval between embolization and tumor extirpation was 2.5 days. The average time required for tumor extirpation was 244 minutes, while the average blood loss was 749 ml. CONCLUSIONS: Our experiences show that Embosphere microspheres are effective embolic agents in obstructing meningeal feeders of preoperatively treated meningiomas.

Adult↗
PubMed1986

[Prognosis of cardiogenic cerebral embolism].

In a retrospective study the reports of 211 cases of cardiogenic cerebral embolism--diagnosed on the base of neurological and cardiological findings--were analyzed in view of signs and findings of prognostic value. There were 21 patients with TIA, 39 cases of RIND and 151 patients with cerebral infarction, 60 of which showed mild and 91 severe neurological symptoms. 38 patients died during the period of hospitalization. While sex of the patients as well as vascular risk factors (hypertension, diabetes mellitus, cigarette smoking) did not influence the clinical course of the disease, patients with TIA or RIND in general were younger (about 5 years) than those with severe stroke. Prognosis of cardiogenic cerebral embolism depended to a great degree on the underlying heart disease. Cerebral embolism after myocardial infarction showed a better remission of symptoms than embolism in atrial fibrillation. In the group of valvular diseases the course of embolic strokes in mitral lesions was worse than in aortal valve disease. Prognosis was worst in endocarditis, both in view of neurological deficit and of mortality. Mostly, the cardiogenic emboli lead to infarctions of the middle cerebral artery territory (78 per cent) with a predilection for the left hemisphere. In media-syndromes the clinical course was significantly worse in patients with additional homonymous visual defect compared to incomplete infarctions. Initial disturbance of conscience reduced prognosis quoad vitam et restitutionem significantly. Of the neuroradiological findings, the detection of arterial occlusion or circulatory disturbance in angiography as well as the finding of an ischemic lesion in computed axial tomography (CAT) was correlated with a severe course of the embolic stroke. While 7 patients with hemorrhagic infarction in CAT-Scan showed no differences in the clinical course, the 14 patients with pathological cerebral spinal fluid findings in embolism had an unfavourable prognosis. The development of epileptic seizures did not influence the further course of the infarction to a significant extent. Results are compared with the current world literature.

Cerebral Infarction↗
PubMed1976

Systemic embolism in chronic sinoatrial disorder.

We attempted to estimate the prevalence of systemic embolism in patients with chronic sino-atrial disorder. In a group of 100 patients, evidence of embolism was found in 16, of whom 15 had the bradycardia-tachycardia syndrome. In 712 controls with chronic complete heart block, who were matched for age and sex, embolism had occurred in only 1.3 per cent (P less than 0.001). A second group of 41 patients with chronic ventricular bradycardia and atrial flutter or fibrillation had an embolic prevalence of 7.3 per cent, which was also greater than that in the controls (P less than 0.05). All patients with sinoatrial disorder in whom systemic embolism developed were over 54 years of age; multiple episodes occurred in six. The risk of embolization remains even if the bradycardia-tachycardia syndrome is replaced by stable atrial fibrillation. Impaired atrial function appears to be a key factor in predisposing to intracardiac thrombosis, and paroxysmal supraventricular tachycardia increases the risk of subsequent embolization.

Age Factors↗
PubMed1994

Elevation of serum creatine kinase in divers with arterial gas embolization.

BACKGROUND: Arterial gas embolism due to pulmonary barotrauma and the resultant cerebral gas embolism are catastrophic complications of diving. Previous studies have only rarely noted evidence of gas embolism to noncranial sites. METHODS: Among 142 persons with diving-related injuries evaluated between January 1982 and July 1991, we identified 29 who had arterial gas embolism and who underwent biochemical studies indicative of muscle injury. Of the 29 patients, 4 were excluded because cardiopulmonary resuscitation had been performed and 3 were excluded because the duration of their dives met or exceeded standard limits set for dives not requiring staged decompression. The outcome at the time of hospital discharge in the remaining 22 patients was correlated with clinical factors and the results of biochemical studies. We also studied 22 subjects after uncomplicated dives and 11 patients who had sustained blunt trauma. RESULTS: All the patients with diving-associated gas embolism had elevated serum creatine kinase activity (normal, < or = 175 U per liter); the values were markedly elevated (> 900 U per liter) in 14. The MB isoenzyme of creatine kinase was detected in the serum of 13 of 20 patients in whom it was measured and was > or = 4 percent of total creatine kinase activity in 6 patients. In three patients electrocardiography showed myocardial injury. Changes in serum creatine kinase activity of similar magnitude were not present in the subjects who had uncomplicated dives or in the patients with blunt trauma. Thirteen patients recovered fully, four had minor residual neurologic deficits, three were severely impaired, and two died. Logistic-regression analysis revealed a significant correlation between peak serum creatine kinase values and clinical outcome. CONCLUSIONS: Biochemical evidence of muscle injury is frequently found after diving-associated arterial gas embolism. The correlation between serum creatine kinase activity and outcome suggests that serum creatine kinase is a marker of the size and severity of arterial gas embolism.

Adolescent↗
PubMed1997

Diagnosis of pulmonary embolism with magnetic resonance angiography.

BACKGROUND: Diagnosing pulmonary embolism may be difficult, because there is no reliable noninvasive imaging method. We compared a new noninvasive method, gadolinium-enhanced pulmonary magnetic resonance angiography, with standard pulmonary angiography for diagnosing pulmonary embolism. METHODS: A total of 30 consecutive patients with suspected pulmonary embolism underwent both standard pulmonary angiography and magnetic resonance angiography during the pulmonary arterial phase at the time of an intravenous bolus of gadolinium. All magnetic resonance images were reviewed for the presence or absence of pulmonary emboli by three independent reviewers who were unaware of the findings on standard angiograms. RESULTS: Pulmonary embolism was detected by standard pulmonary angiography in 8 of the 30 patients in whom pulmonary embolism was suspected. All 5 lobar emboli and 16 of 17 segmental emboli identified on standard angiograms were also identified on magnetic resonance images. Two of the three reviewers reported one false positive magnetic resonance angiogram each. As compared with standard pulmonary angiography, the three sets of readings had sensitivities of 100, 87, and 75 percent and specificities of 95, 100, and 95 percent, respectively. The interobserver correlation was good (k=0.57 to 0.83 for all vessels, 0.49 to 1.0 for main and lobar vessels, and 0.40 to 0.81 for segmental vessels). CONCLUSIONS: In this preliminary study, gadolinium-enhanced magnetic resonance angiography of the pulmonary arteries, as compared with conventional pulmonary angiography, had high sensitivity and specificity for the diagnosis of pulmonary embolism. This new technique shows promise as a noninvasive method of diagnosing pulmonary embolism without the need for ionizing radiation or iodinated contrast material.

Adult↗
PubMed2000

Right trisegment portal vein embolization for biliary tract carcinoma: technique and clinical utility.

BACKGROUND: Right portal vein embolization has become popular in preparation for right hepatic lobectomy. However, right trisegment portal vein embolization (R3PE) is not well established. METHODS: We performed R3PE in 15 patients with biliary tract carcinoma and 1 patient with primary sclerosing cholangitis. We used 2 types of 5.5 F triple-lumen balloon catheters to embolize portal branches of the right trisegment (the left medial, the right anterior, and the right posterior segments). RESULTS: R3PE was successful in all patients without any complications. The calculated volume of the right lobe significantly (P < .01) decreased from 650 +/- 161 cm3 before embolization to 585 +/- 143 cm3 after embolization; the volume of the left lateral segment significantly (P < .0005) increased from 240 +/- 58 cm3 to 361 +/- 66 cm3. The volume of the left medial segment was unchanged. The volume gain of the left lateral segment was larger in patients with R3PE than in those patients (n = 41) with right portal vein embolization (122 +/- 39 cm3 vs 66 +/- 35 cm3; P < .0001). Two of the 16 patients underwent only laparotomy because of peritoneal dissemination, and the remaining 14 patients underwent right hepatic trisegmentectomy with caudate lobectomy. In addition, portal vein resection was also performed in 5 patients, and pancreatoduodenectomy and right hemicolectomy was performed in 3 patients. One patient died of posthepatectomy liver failure 87 days after surgery, a mortality rate of 7.1% (1/14 patients). CONCLUSIONS: R3PE is more useful than standard right portal vein embolization in preparation for right hepatic trisegmentectomy and has the potential to increase the safety of this high-risk surgery for patients with biliary tract carcinoma.

Adult↗
PubMed1993

Reconstruction of the ligated external carotid artery for embolization of cervicofacial arteriovenous malformations.

PURPOSE: Until recently, the accepted management of life-threatening complications of unresectable cervicofacial arteriovenous malformations (AVMs) has been ligation of the major feeding vessels, usually the branches or the main trunk of the external carotid artery. Rapid enlargement of collateral vessels around the ligature is usually associated with an early return of symptoms. Percutaneous transcatheter embolization of the nidus of the arteriovenous malformation is now the preferred treatment for symptomatic AVMs that cannot be excised. Previous ligation of the main feeding vessels prevents catheter access and embolization therapy of the lesion. The purpose of this report is to describe our experience with the treatment of patients with symptomatic unresectable cervicofacial AVMs and previous external carotid artery ligation. METHODS: Six patients with symptoms from cervicofacial arteriovenous malformations required surgical reconstruction of their previously ligated external carotid artery with the anticipation of catheter embolization therapy to the branch vessels feeding the malformation. Saphenous vein was used in five reconstructions; a polytetrafluoroethylene graft was used in one. RESULTS: After successful arterial reconstruction, massive swelling of the tongue and perioral tissue developed in two patients, which necessitated tracheostomy in one patient; and embolization therapy before extubation could be safely performed in the other patient. In all, four patients underwent successful embolization therapy. One refused subsequent treatment. In one patient with severe epistaxis, external carotid artery revascularization led to the healing of the nasal ulcers without need for embolization therapy. CONCLUSIONS: For patients with previous ligations of the external carotid artery and symptomatic AVMs, revascularization of the external carotid artery is an important step in treatment. The surgery must be carefully coordinated with the interventional radiologist for possible emergency postoperative embolization therapy. External carotid artery ligation only complicates the treatment of patients with cervicofacial AVMs, and should no longer be used in the treatment of these individuals.

Adult↗
PubMed2001

Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: an experimental analysis.

OBJECTIVE: The role of percutaneous angioplasty and stenting of carotid bifurcation lesions has been limited by its potential for producing embolic debris. We evaluated the efficacy of a proximal occlusion catheter (POC) in the prevention of embolic events during carotid artery stenting. In addition, pressure measurements relevant to the clinical application of this device were obtained from 10 patients undergoing carotid endarterectomy. METHODS: The POC is a guiding catheter with an occlusion balloon attached on the outside of the catheter at its distal end. Occlusion of the common carotid artery (CCA) was achieved by inflating the balloon while access to carotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of the POC was connected to a sheath placed in the femoral vein, thereby creating an external arteriovenous shunt. Ten artificial radiopaque particles simulating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patients undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal jugular vein were measured. RESULTS: Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was derived from the thyroid artery. However, once the arteriovenous shunt was activated, reversal of flow in the distal CCA was achieved in each animal, and all the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P <.01). In the patients, the mean stump pressures in the ICA and external carotid artery and the jugular vein pressure were 51.8 +/- 14.2, 62.2 +/- 15.1, and 6.5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three. CONCLUSIONS: Obtaining proximal CCA control by inflating the POC does not sufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embolization. Thus, POC may markedly lower procedural stroke rates during carotid artery stenting. The ability of POC to prevent embolization before crossing the lesion with a guidewire may be an important advantage over other distal protection devices.

Angioplasty, Balloon↗
PubMed2001

Hypogastric artery embolization in endovascular abdominal aortic aneurysm repair.

PURPOSE: Iliac artery anatomy is a central factor in endoluminal abdominal aortic aneurysm therapy. It serves as the conduit for graft deployment and as the region of distal graft seal. Thirty-eight percent of iliac vessels in our patients require special treatment because of aneurysms, tortuosity, or small size. Bilateral hypogastric artery exclusion has been avoided because of concerns of colorectal ischemia, hip/buttock claudication, and impotence. We suggest that elective, staged, bilateral hypogastric embolization can be performed safely with reasonably low morbidity and can expand the anatomic boundaries for stent-graft abdominal aortic aneurysm repair. METHODS: This study was performed as a retrospective chart review of patients requiring hypogastric artery embolization for endovascular repair of abdominal aortic aneurysms between June 1998 and June 2000. Patients with otherwise appropriate anatomy and common iliac artery aneurysms were informed of the option for stent-graft repair with internal iliac artery embolization with its risks of impotence, hip/buttock claudication, and bowel ischemia. Patients underwent unilateral or staged bilateral coil embolizations of their proximal hypogastric arteries with an approximate 1-week interval between procedures. Hospital and office records were reviewed; phone interviews were performed. Follow-up ranged from 1 to 12 months. RESULTS: During a 24-month period, 65 patients underwent endovascular abdominal aortic aneurysm repair; 18 patients (28%) required hypogastric artery embolization. Seven (39%) of these patients underwent bilateral embolization. There were no episodes of clinically evident bowel ischemia. Lactate levels were normal in all measured patients. Postoperative fevers (> 101.0 degrees F) were documented in 10 (56%) of 18 patients. The average white blood cell count was 12.8 x 10(9)/L (range, 8.5-22.9). There were no positive blood culture results. The return to the full preoperative diet occurred in 1 to 3 days. Hip/buttock claudication occurred in approximately 50% of patients with persistent but improved symptoms at 6 months. Eighty-seven percent of patients had preoperative erectile dysfunction. Only two patients noted worsening of erectile function postoperatively. CONCLUSIONS: Preliminary results indicate that bilateral hypogastric artery embolization can be performed, when necessary, with reasonable morbidity in patients undergoing stent-graft abdominal aortic aneurysm repair.

Aged↗
PubMedDate not supplied

Effect of venous air embolization on pulmonary microvascular protein permeability.

OBJECTIVE: An increase in pulmonary lymph flow and lymph protein clearance following pulmonary air embolization has been interpreted as evidence of increased pulmonary microvascular permeability. The authors hypothesized that air embolization does not alter the pulmonary microvascular permeability to protein and that this could be demonstrated by determining the effect of air embolization on the pulmonary solvent drag reflection coefficient (sigma(f)). METHODS: Anesthetized dogs were instrumented with left atrial balloon-tipped catheters, pulmonary lymphatic cannulae, and inferior vena caval catheters. Values were determined for pulmonary lymph flow (Q(L)) and the lymph-to-plasma protein concentration ratio (C(L)/C(P)) at baseline, after C(L)/C(P) was decreased to a filtration independent value by raising left atrial pressure via progressive balloon inflation and after 2 h of air embolization into the inferior vena cava with continued left atrial hypertension. RESULTS: Q(L) increased and C(L)/C(P) decreased to a filtration-independent value following induction of left atrial hypertension. Air embolization induced during left atrial hypertension resulted in no significant change in C(L)/C(P). The authors were unable to demonstrate that sigma(f) changed following pulmonary air embolization. CONCLUSIONS: Utilizing the washdown technique, the authors could not find any evidence that pulmonary microvascular protein permeability is altered by air embolization.

Animals↗
PubMed2003

Pulmonary embolism: differences in presentation between older and younger patients.

BACKGROUND: the incidence of pulmonary embolism increases with age but the 'classical' presentation of acute pulmonary embolism may not occur in older persons. OBJECTIVES: to compare the clinical presentation of younger and older patients with acute pulmonary embolism. DESIGN: retrospective identification of 60 consecutive cases of spiral computed tomography confirmed acute pulmonary embolism over a 3-year period, with blinded review of radiological films and electrocardiographs, and analysis of clinical presentation. SETTING: a district general hospital serving a population of 200,000 people. SUBJECTS: 31 younger and 29 older patients with acute pulmonary embolism. RESULTS: older persons less often complained of pleuritic chest pain (P < 0.02), particularly as their primary presenting complaint (P < 0.002). Twenty-four percent of older but just 3% of younger persons presented with collapse (P < 0.02), despite similar proportions of central and peripheral emboli in the two groups. Older persons were more often cyanosed (P = 0.05) and hypoxic (P < 0.04) than younger persons but there were no significant differences with respect to heart rate, respiratory rate or mean arterial blood pressure. CONCLUSIONS: older people present atypically with acute pulmonary embolism, potentially leading to delays in diagnosis and initiation of treatment. Collapse is a particularly important symptom of acute pulmonary embolism in older persons, even in the absence of pain.

Aged↗
PubMed2000

Comparison of preoperative embolization followed by radical nephrectomy with radical nephrectomy alone for renal cell carcinoma.

A series of 474 patients with renal cell carcinoma (RCC), who had radical nephrectomy during a period of 15 years, was studied to assess the prognostic significance of various pathologic parameters (tumor stage [pT], lymph node status, metastasis, tumor grade, venous involvement) and value of preoperative embolization of renal artery. There were: 20 (4%) pT1, 204 (43%) pT2, 245 (52%) pT3, and 5 (1%) pT4 patients. All 474 patients underwent nephrectomy including a group of 118 (25%) patients (24 pT2, 90 pT3, and 4 pT4) who underwent preoperative embolization of the renal artery. To compare treatment outcomes in embolized patients with RCC, a group of 116 (24%) nonembolized patients with RCC was selected. This group was matched for sex, age, stage, tumor size, and tumor grade, with the embolized patients (p<0.01). All important prognostic factors were studied as to their influence on survival by the treatment group. The overall 5- and 10-year survival was 62% and 47%, respectively. The 5- and 10-year survival rates were significantly better (p<0.01) for patients with pT2 than for those with pT3 tumors (79% vs. 50% and 59% vs. 35%, respectively). Involvement of regional lymph nodes (N+) was an important prognostic factor for survival in patients with pT3 tumors. The 5-year survival for pT3 N+ was 39%, compared with 66% in those with pT3N0 (p<0.01). Preoperative embolization was also an important factor influencing survival. The overall 5- and 10-year survival for 118 patients embolized before nephrectomy was 62% and 47%, respectively, and it was 35% and 23%, respectively, for the matched group of 116 patients treated with surgery alone (p = 0.01). The most important finding of this study was an apparent importance of preoperative embolization in improving patients' survival. This finding needs to be interpreted with caution and confirmed in a prospective randomized trial.

Adult↗
PubMed1986

Transcutaneous O2 and CO2 monitoring of neurosurgical patients: detection of air embolism.

Transcutaneous oxygen tension (PtcO2) and transcutaneous carbon dioxide tension (PtcCO2) were monitored in 60 patients undergoing neurosurgical procedures. Twenty-six patients were in the sitting position and underwent routine monitoring for air embolism. Seventeen episodes of air embolism were diagnosed by precordial Doppler ultrasound or transesophageal echocardiography, and the PtcO2 decreased early during the course of each episode. The mean PtcO2 decrease was 48 +/- 35 mmHg. During ten episodes the end-tidal carbon dioxide tension (PETCO2) decreased but only after the PtcO2 had already begun to decrease. PtcCO2 increased during air embolism but PETCO2 changes preceded the change in PtcCO2 by 1-2 min. Transcutaneous values during air embolism were verified with simultaneous arterial blood gas values during six air embolism episodes. A strong positive correlation was found between transcutaneous and arterial oxygen and carbon dioxide tensions. Correcting the PtcCO2 by the patient's baseline PtcCO2/PaCO2 ratio, PtcCO2 monitoring correctly reflected hypocarbia, normocarbia, and hypercarbia in 92% of the cases. PtcO2 monitoring was useful in detecting venous air embolism and may respond sooner than PETCO2. PtcCO2 monitoring was not useful as an early detector of air embolism.

Adult↗
PubMed1996

Diagnosis and management of paradoxical embolism and patent formen ovale.

Recent investigations of patients with cerebral and peripheral arterial emboli of unknown cause suggest that paradoxical embolism through a patent formen ovale (PFO) might be responsible for more arterial embolic events than previously realized. In most cases, however, a causal relationship between the embolic process and the PFO cannot be established with certainty. The presumptive nature of the clinical diagnosis of paradoxical embolism together with the lack of precise data on the risk of recurrent embolization do not facilitate the proper treatment of these patients. In the rare case of proved paradoxical embolism with a thrombus straddling a PFO discovered by echocardiography, the available literature suggest that embolectomy and closure of the PFO is the most logical approach. The long-term treatment of patients with presumed paradoxical embolism is controversial. Further studies are needed to assess the risk of recurrent arterial ischemic events associated with PFO, to determine which patients are at increased risk of recurrent events, and to assess the potential benefits from various therapeutic interventions (anticoagulants or antiplatelet drugs, surgical or transcatheter closure of the PFO). Otherwise, we risk exposing these patients to unnecessary treatment complications.

Embolism, Paradoxical↗
PubMed1992

Venous air embolism: clinical and experimental considerations.

OBJECTIVE: To examine the existing literature concerning venous air embolism. Causes, pathophysiology, and management are emphasized. DATA SOURCES: The literature that was reviewed was retrieved from the MEDLINE System under the headings "venous air embolism," "air embolism," "therapy of air embolism," "etiology of venous air embolism," and "pathophysiology of venous air embolism" for the years 1970 to 1991. A manual search, derived from the references of these papers, was performed to obtain relevant citations for the years preceding 1970. STUDY SELECTION: Experimental (animal) data, case reports, case series, and clinical investigations are included. CONCLUSIONS: Venous air embolism is an infrequent complication of invasive diagnostic and therapeutic maneuvers. The cardiovascular, pulmonary, and central nervous systems may all be affected, with severity ranging from no symptoms to immediate cardiovascular collapse. Therapeutic interventions include mechanical measures, such as positioning, withdrawal of air from the right atrium, and measures aimed at reducing bubble size. Hyperbaric oxygen therapy holds some promise in accomplishing the latter, but randomized, controlled trials demonstrating efficacy have yet to be performed.

Animals↗
PubMed1986

Transcatheter renal arterial embolization with the mixture of ethanol and iodized oil (Lipiodol).

We induced experimental renal arterial embolization with the radiopaque solution of ethanol and iodized oil (Lipiodol) in 35 rabbits to evaluate the capability of the mixture to induce renal ablation. Serial renal angiography and plain abdominal radiography were performed immediately, one week and two weeks after embolization. Neither pure Lipiodol nor a 50% ethanol solution caused renal embolization. However, infusion of 50% and 75% ethanol-Lipiodol solutions resulted in embolization equal to that caused by absolute ethanol. The 50% ethanol-Lipiodol solution was so radiopaque that we could easily observe the embolization process during fluoroscopy. Renal arterial embolization with the 50% ethanol-Lipiodol solution was successful in three patients with hypernephroma. Our results suggest that a 50% ethanol-Lipiodol solution is radiopaque and an effective agent for renal arterial embolization.

Animals↗
PubMedDate not supplied

Regional relative blood volume MR maps of meningiomas before and after partial embolization.

PURPOSE: Our goal was to evaluate the role of relative blood volume (rBV) measurements in monitoring the embolization effect in meningiomas by using maps of susceptibility-weighted first pass MR data. METHOD: Eighteen examinations of nine patients before and following partial embolization were performed on a 1.5 T scanner. Embolization was achieved by injection of particles (45-150 microns). During dynamic imaging a bolus (0.2 mmol/kg) of gadopentetate dimeglumine was injected. RESULTS: The tumor rBV/gray matter rBV ratio was 3.11 +/- 1.40 for untreated tumors and 0.12 +/- 0.09 for successfully embolized tumors. The regional rBV in embolized meningiomas was significantly lower than that in untreated meningiomas (t test, p < 0.001). Vital tumor tissue showed positive enhancement in T1 and high rBV; nonvital tissue lacked T1 enhancement and bolus effect in the first pass, thus leading to low or missing rBV values. However, we also observed lack of bolus formation despite T1 enhancement (6/9 postembolization regions), possibly due to slow collateral flow. One of the patients treated with embolization bled during surgery. CONCLUSION: Maps of relative regional cerebral BV provide hemodynamic information in meningiomas and monitor the treatment effect of embolization in meningiomas more precisely than T1-weighted contrast-enhanced imaging.

Blood Loss, Surgical↗
PubMedDate not supplied

Detection of central pulmonary embolism on computed tomography densitometry images before computed tomography pulmonary angiography.

OBJECTIVE: The purpose of this article is to describe the imaging findings of acute central pulmonary embolism on computed tomography (CT) densitometry images performed before contrast-enhanced CT pulmonary angiography. METHODS: A retrospective review was conducted of reports from all CT pulmonary angiograms performed at our institution, and cases of acute central pulmonary embolism, defined as those with clot in the main, left, or right pulmonary arteries, were identified. Images of positive studies were reviewed on a picture archiving and communications system (PACS) workstation. RESULTS: A total of 1282 CT pulmonary angiograms were obtained for evaluation of possible acute pulmonary embolism, and 1 combined CT aortogram and pulmonary angiogram was performed for aortic dissection and acute pulmonary embolism. Two hundred fourteen (16.7%) examinations positive for acute pulmonary embolism were identified, 26 (12.1%, 2.0% of total examinations) of which had central clots. Of the 26 patients with central acute pulmonary embolism, 12 (46.1%, 5.6% of all positive studies and 0.9% of all CT pulmonary angiograms) had clots that were visible on the densitometry images. CONCLUSION: Although an uncommon finding, acute central pulmonary embolism can be detected on CT densitometry performed to optimize opacification of the pulmonary arteries for CT pulmonary angiography and may prove useful in selected clinical situations.

Acute Disease↗