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Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Risk factors for acute venous occlusion range from prolonged immobilization to hypercoagulability syndromes, trauma, and malignancy. The aim of this review article is to illustrate the different imaging options for the diagnosis of acute venous occlusion and to assess the value of interventional strategies for venous thrombosis treatment in an emergency setting.First, diagnosis and treatment of the most common form of venous occlusion, at the level of the lower extremities, is presented, followed by pelvic vein and inferior vena cava occlusion, mesenteric venous thrombosis, upper extremity occlusion, acute cerebral vein thrombosis, and finally acute venous occlusion of hemodialysis access.In acute venous occlusion of the lower extremity phlebography is still the reference gold standard. Presently, duplex ultrasound with manual compression is the most sensitive and specific noninvasive test. Limitations of ultrasonography include isolated distal calf vein occlusion, obesity, and patients with lower extremity edema. If sonography is nondiagnostic, venography should be considered. Magnetic resonance venography can differentiate an acute occlusion from chronic thrombus, but because of its high cost and limited availability, it is not yet used for the routine diagnosis of lower extremity venous occlusion only. Regarding interventional treatment, catheter-directed thrombolysis can be applied to dissolve thrombus in charily selected patients with symptomatic occlusion and no contraindications to therapy. Acute occlusion of the pelvic veins and the inferior vena cava, often due to extension from the femoropopliteal system, represents a major risk for pulmonary embolism. Color flow Doppler imaging is often limited owing to obesity and bowel gas. Venography has long been considered the gold standard for identifying proximal venous occlusion. Both CT scanning and MR imaging, however, can even more accurately diagnose acute pelvis vein or inferior vena cava occlusion. MRI is preferred because it is noninvasive, does not require contrast agent, carries no exposure to ionizing radiation, and is highly accurate and reproducible. Apart from catheter-directed thrombolysis, mechanical thrombectomy has proven to be a quick and safe treatment modality by enabling the recanalization of thrombotic occlusions in conjunction with minimal invasiveness and a low bleeding risk. Mechanical thrombectomy devices should only be used in conjunction with a temporary cava filter.Contrast-enhanced CT is at present considered the examination of choice for acute mesenteric vein occlusion which has mortality rates as high as 80%. Patients with proven acute mesenteric venous occlusion and contraindications to surgical therapy and no identified bleeding disposition without looming bowel ischemia or infarction are possible contenders to the less invasive percutaneous approach either by (in)direct thrombolysis or mechanical means. Ultrasonography is the primary imaging modality for the diagnosis of upper extremity thrombosis. Computed tomography and MRI are in addition helpful in diagnosing central chest vein occlusions. The interventionalist is rarely involved in the treatment of this entity. Catheter-directed thrombolysis is known to improve lysis rates. Together with balloon angioplasty good results have been obtained. If stenosis or thrombus remains after thrombolysis and angioplasty, stent placement should follow. Within the first two weeks, thrombosed dural sinus and cerebral venous vessels are typically hyperdense on CT compared with brain parenchyma; after the course of 2 weeks, the thrombus will become isodense. In MRI an axial fluid-attenuated inversion recovery sequence, an axial diffusion-weighted MRI, coronal T1-weighted spin-echo and T2-weighted turbo-spin-echo sequences, a coronal gradient-echo and a 3D phase-contrast venous angiogram should be performed. Local thrombolysis is needed only when patients have an exacerbation of clinical symptoms or imaging signs of worsening disease despite sufficient anticoagulation therapy. Acute occlusions of dialysialysis grafts and fistulae are a frequently encountered complication. Among the various methods described for acute occlusion screening, ultrasonography and MRI have been proven to be accurate and noninvasive; however, if immediate treatment can be anticipated, imaging should be performed directly by digital subtraction angiography before the percutaneous intervention. Initial percutaneous thrombectomy is very effective with success rates and patency rates comparable to those of surgical thrombectomy. A short thrombosis can be treated with balloon angioplasty alone, whereas an extensive thrombosis requires a combination of mechanical devices and/or thrombolytic agents with adjunctive balloon angioplasty.
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PMID:Nontraumatic vascular emergencies: imaging and intervention in acute venous occlusion. 1238 51

This review discusses real-time pulmonary ultrasonography (US) for the practicing pulmonologist. US supplements chest radiography and chest CT scanning. Major advantages include bedside availability, absence of radiation, and guided aspiration of fluid-filled areas and solid tumors. Pulmonary vessels and vascular supply of consolidations may be visualized without contrast. US may help to diagnose conditions such as pneumothorax, hemothorax, pleural or pericardial effusion, pneumonia, and pulmonary embolism in the critically ill patient who is in need of bedside diagnostic testing. The technique of US, which is cost-effective compared to CT scanning and MRI, may be learned relatively easily by the pulmonologist.
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PMID:Real-time chest ultrasonography: a comprehensive review for the pulmonologist. 1242 82

No single noninvasive test for pulmonary embolism is both sensitive and specific. Some tests are good for "ruling in" pulmonary embolism (e.g., helical CT) and some tests are good for "ruling out" pulmonary embolism (e.g., D-dimer); others are able to do both but are often nondiagnostic (e.g., ventilation-perfusion lung scanning). For optimal efficiency, choice of the initial diagnostic test should be guided by clinical assessment of the probability of pulmonary embolism and by patient characteristics that may influence test accuracy. This selective approach to testing enables pulmonary embolism to be diagnosed or excluded in a minimum number of steps. However, even with the appropriate use of combinations of noninvasive tests, it is often not possible to definitively diagnose or exclude pulmonary embolism at initial presentation. Most of these patients can be managed safely without treatment or pulmonary angiography by repeating ultrasound testing of the proximal veins after one and 2 weeks to detect evolving deep vein thrombosis. Helical CT and MRI are rapidly improving as diagnostic tests for pulmonary embolism and are expected to become central to its evaluation.
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PMID:Diagnosis of pulmonary embolism. 1277 Oct 73

Recently, patent foramen ovale(PFO) has been highlighted as an important risk factor of cerebral infarctions in young adults. We report a patient of multiple cerebral embolism associated with PFO and deep venous thrombosis caused by a uterine myoma. A 40-year-old woman suddenly suffered from right hemiparesis with motor aphasia. Brain angiography showed an occlusion of M2 portion of the left middle cerebral artery, but atherosclerotic changes were not seen. She developed left facial paresis 23 days later and admitted to our hospital. Brain MRI revealed multiple cerebral infarcts in the left insular cortex, the deep white matter of the right frontal lobe, and bilateral thalamus. Hypoxia with the perfusion defects of S1 and S2 sections of the right lung demonstrated by scintigraphy suggested pulmonary embolism. Transesophageal echocardiography showed a PFO with spontaneous left-to-right shunt and right-to-left shunt evoked by the Valsalva maneuver. Although venography could not detect thrombi, it revealed severe compression of the right external iliac vein by a uterine myoma. These findings suggested thrombi in the right external iliac vein were the embolic source when combined with elevated coagulation markers. An uterine myoma should be considered as an important risk factor for an embolic source in case of cerebral embolism with PFO.
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PMID:[Multiple cerebral embolism caused by a patent foramen ovale and a uterine myoma]. 1367 5

The feasibility and diagnostic value of real-time magnetic resonance imaging (RT-MRI) for the diagnosis of acute pulmonary embolism (PE) was evaluated by comparing RT-MRI and magnetic resonance angiography (MRA). In 39 consecutive patients with suspected PE real-time true fast imaging with steady-state precession (TrueFisp) was prospectively compared with contrast-enhanced MRA on a 1.5-T MR scanner. The TrueFisp sequence used allowed acquisition of T2-weighted images at 0.4 s per image so that the pulmonary vasculature could be visualized in three orientations in <3 min without the need for breath holding or contrast media application. Results of additional scintigraphic pulmonary perfusion examinations were available from 17 patients. All 39 primary RT examinations (100%) and 30 of 39 MRA examinations (77%) were of diagnostic quality. The reasons underlying failure to achieve diagnostic quality for MRA were breathing artifacts among dyspneic patients in all 9 cases. Compared with MRA, the sensitivities and specificities of RT sequences for PE were 93 and 100% (per examination), 96 and 100% (lobar artery PE), and 97 and 100% (segmental artery PE), respectively. Compared with scintigraphy, the sensitivity and specificity of RT-MRI were 83 and 100%, respectively. The MRA reached 100% sensitivity and specificity in this subgroup. The RT-MRI proved to be very robust and undisturbed by respiratory movements and patient cooperation. Its image quality assured fast diagnostic examinations, and its sensitivity and specificity, compared with MRA and scintigraphy, were sufficient to allow the diagnosis of acute central, lobar, and segmental PE; therefore, the emergency diagnosis of PE using RT-MRI is feasible and reliable.
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PMID:Real-time MR with TrueFISP for the detection of acute pulmonary embolism: initial clinical experience. 1465 1

Several radiological imaging modalities are available to assist with the clinical diagnosis of pulmonary embolism (PE). The most frequently used techniques-nuclear medicine ventilation-perfusion (VP) scan, computed tomography (CT), magnetic resonance angiography (MRA), and pulmonary angiography (PA)-all have literature-supported, substantial limitations with respect to timeliness and patient safety. Hyperpolarized 3He magnetic resonance gas distribution imaging (HP 3He MRI) recently has shown potential as a safer and faster alternative. In this study, we performed HP 3He MRI on a porcine model (N = 6) of simulated PE using selective occlusion balloon catheterization (N = 4) and nonselective aged autologous clot injection (N = 1). The technique was also performed on a normal pig and again after the animal was killed. Temporal depletion of regional HP 3He MRI signal intensity provided for a qualitative assessment of simulated PE (N = 4), and regional PAO2 (alveolar partial pressure of oxygen) was calculated in affected airspaces for a quantitative assessment of simulated PE (N = 1). The preliminary results suggest that HP (3)He MRI shows promise as a means of assessing regional pulmonary perfusion abnormalities in the porcine models of simulated PE that were used in this study.
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PMID:Detection of simulated pulmonary embolism in a porcine model using hyperpolarized 3He MRI. 1475 54

Primary vascular leiomyosarcomas are very rare tumors, with the venous variety most often arising from the inferior caval vein and the arterial variety from the pulmonary artery. The tumors show either an exclusive intra- or extravascular pattern or a mixed growth pattern. The clinical symptoms depend on tumor location, with intraluminal tumors of the inferior caval vein causing edema or a Budd-Chiari syndrome. Leiomyosarcomas of the pulmonary artery can mimic chronic central or recurrent peripheral pulmonary embolism. Contrast enhanced spiral CT with multiplanar reconstruction is the diagnostic method of choice when a vascular leiomyosarcoma is suspected. MRI with MR-angiography can be added. If a tumor of undetermined origin shows a broad contact with a vessel and/or an intraluminal component, possible primary vascular leiomyosarcoma should be included in the differential diagnosis.
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PMID:[Diagnostic imaging of vascular leiomyosarcomas]. 1487 71

The purpose of this study was to assess the feasibility of contrast-enhanced 3D perfusion MRI and MR angiography (MRA) of pulmonary embolism (PE) in pigs using a single injection of the blood pool contrast Gadomer. PE was induced in five domestic pigs by injection of autologous blood thrombi. Contrast-enhanced first-pass 3D perfusion MRI (TE/TR/FA: 1.0 ms/2.2 ms/40 degrees; voxel size: 1.3 x 2.5 x 4.0 mm3; TA: 1.8 s per data set) and high-resolution 3D MRA (TE/TR/FA: 1.4 ms/3.4 ms/40 degrees; voxel size: 0.8 x 1.0 x 1.6 mm3) was performed during and after a single injection of 0.1 mmol/kg body weight of Gadomer. Image data were compared to pre-embolism Gd-DTPA-enhanced MRI and post-embolism thin-section multislice CT (n = 2). SNR measurements were performed in the pulmonary arteries and lung. One animal died after induction of PE. In all other animals, perfusion MRI and MRA could be acquired after a single injection of Gadomer. At perfusion MRI, PE could be detected by typical wedge-shaped perfusion defects. While the visualization of central PE at MRA correlated well with the CT, peripheral PE were only visualized by CT. Gadomer achieved a higher peak SNR of the lungs compared to Gd-DTPA (21 +/- 8 vs. 13 +/- 3). Contrast-enhanced 3D perfusion MRI and MRA of PE can be combined using a single injection of the blood pool contrast agent Gadomer.
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PMID:3D pulmonary perfusion MRI and MR angiography of pulmonary embolism in pigs after a single injection of a blood pool MR contrast agent. 1499 36

The clinical picture of cerebral venous thrombosis (CVT) depends on the site of thrombosis in the venous system including superficial veins, deep veins and venous sinuses. Thrombotic changes may occur simultaneously in various parts of the venous system. Since CVT may have various causes, the knowledge of its etiology helps to make the diagnosis. In systemic diseases multiple intravascular clots may result, while in localized pathological conditions thrombosis maybe restricted to the lesion site. The clinical picture is often serious, leading to death, or to severe complications such as pulmonary embolism, and to distant complications--like epilepsy or intracranial hypertension being the cause of chronic headaches (lumbar puncture and CSF pressure measurement are helpful in the diagnosis of intracranial hypertension). In order to prevent complications of crucial importance is not only the proper diagnosis (with MRI and venography as the diagnostic techniques of choice), but also an early and prolonged treatment with anticoagulants. Heparin or fractionated heparin is recommended even though there is a possibility of cerebral haemorrhagic lesions.
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PMID:[Cerebral venous thrombosis--clinical aspects and consequences]. 1517 53

A 22-year-old woman with a newly detected chondroid liposarcoma located in the iliac muscle was diagnosed as having bilateral pulmonary embolism. Gadolinium-enhanced MRI further revealed a long distance thrombus reaching from the iliac vein to the right atrium. The thrombus was attributed to a hypercoagulability state which has been described for chondroid liposarcoma. High-dose chemotherapy with autologous stem cell support reduced the tumor burden and led to a symptom-free interval of 6 months. Despite therapeutic anticoagulation, repeated imaging showed no reduction or remodeling of the thrombus. However, when the thrombus progressed again, the patient underwent cardiac surgery and histology revealed the intravascular growth of the known chondroid liposarcoma. We conclude that in sarcoma patients intravascular tumor growth must be kept in mind when imaging is suggestive for thrombosis.
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PMID:Thrombectomy discloses intravascular growth of chondroid liposarcoma mimicking a long distance vena cava thrombosis. 1536 85


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