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PubMed1993

X-ray angiography systems.

Despite the emergence of several alternative angiographic imaging techniques (i.e., magnetic resonance imaging, computed tomography, and ultrasound angiography), x-ray angiography remains the predominant vascular imaging modality, generating over $4 billion in revenue a year in U.S. hospitals. In this issue, we provide a brief overview of the various angiographic imaging techniques, comparing them with x-ray angiography, and discuss the clinical aspects of x-ray vascular imaging, including catheterization and clinical applications. Clinical, cost, usage, and legal issues related to contrast media are discussed in "Contrast Media: Ionic versus Nonionic and Low-osmolality Agents." We also provide a technical overview and selection guidance for a basic x-ray angiography imaging system, including the gantry and table system, x-ray generator, x-ray tube, image intensifier, video camera and display monitors, image-recording devices, and digital acquisition and processing systems. This issue also contains our Evaluation of the GE Advantx L/C cardiac angiography system and the GE Advantx AFM general-purpose angiography system; the AFM can be used for peripheral, pulmonary, and cerebral vascular studied, among others, and can also be configured for cardiac angiography. Many features of the Advantx L/C system, including generator characteristics and ease of use, also apply to the Advantx AFM as configured for cardiac angiography. Our ratings are based on the systems' ability to provide the best possible image quality for diagnosis and therapy while minimizing patient and personnel exposure to radiation, as well as its ability to minimize operator effort and inconvenience. Both units are rated Acceptable. In the Guidance Section, "Radiation Safety and Protection," we discuss the importance of keeping patient and personnel exposures to radiation as low as reasonably possible, especially in procedures such as cardiac catheterization, angiographic imaging for special procedures, and interventional radiology, which produce among the highest radiation exposure of all x-ray imaging techniques. We also provide recommendations for minimizing personnel and patient exposures to radiation. For more information about x-ray angiography systems and similar devices, as well as for additional perspectives on which we based this study, see the following Health Devices Evaluations: "Mobile C-arm Units" (19[8], August 1990) and "Noninvasive Electronic Quality Control Devices for X-ray Generator Testing" (21[6-7], June-July 1992).(ABSTRACT TRUNCATED AT 400 WORDS)

Angiography↗
PubMed1995

[Magnetic resonance angiography of intracranial aneurysms after subarachnoid hemorrhage].

Magnetic resonance angiography is now commercially available for a variety of scanners and is being increasingly applied in the diagnosis of cerebrovascular disorders. Considering the clinical consequences, especially in intracranial aneurysms, studies to determine the sensitivity and specificity of the method are essential. Here we report our experience with a 3D-FISH time-of-flight magnetic resonance angiography protocol in 52 patients who have suffered an acute subarachnoid hemorrhage. In 26 of the 52 patients, conventional angiography identified 31 aneurysms (3-20 mm) that were confirmed during surgery or autopsy. Magnetic resonance angiography correctly identified 28 of the 31 aneurysms (sensitivity 90.3%) and missed one ruptured (3 mm) and two incidental aneurysms (3 mm) in patients with multiple aneurysms. The sensitivity for a ruptured aneurysm was 96%. The 26 patients who suffered subarachnoid hemorrhage without evidence of an intracranial aneurysm on repeated angiography served as a control group. Magnetic resonance angiography revealed no false-positive findings, resulting in a specificity of 100%. In correlation with the literature, we conclude that magnetic resonance angiography is not sensitive enough for the management of acute subarachnoid hemorrhage. However, the method provides important complementary information for definition of the bleeding site in patients with multiple aneurysms. In addition, the calculation of projections not possible with conventional angiography can aid surgical planning. Since only very small aneurysms were missed by magnetic resonance angiography, the sensitivity seems appropriate to screen asymptomatic patients who are at risk for intracranial aneurysms.

Adolescent↗
PubMed1996

[Percutaneous radial approach for coronary angiography].

BACKGROUND: The Sones technique for coronary angiography has been abandoned by most of laboratories. Nevertheless, in some circumstances (anticoagulation, peripheral arteriopathy, outpatients procedures), the femoral entry site may be troublesome. We evaluated the feasibility and safety of percutaneous transradial approach to coronary angiography as an alternative way to the usual femoral approach. METHODS: Since July to october 1995 we performed 200 consecutive coronary angiographies via radial artery with percutaneous approach. Exclusion criteria were the absence of radial pulse, abnormal Allen test and the need to perform right catheterism. No patient was excluded because of age or other clinical reason. We used right radial artery in 192 cases, left radial artery in 7 cases and both right and left artery in 7 cases. Thirteen patients (6.5%) had previous CABG. Thirteen patients were under treatment with heparin or dicoumarol. Twenty-one patients (10.5%) were affected by lower extremities arteriopathy. Five patients had previous coronary angiography by Sones technique. Fifty-eight patients (29%) underwent coronary angiography on outpatient basis. We used 6 F catheters in all cases but one. 5000 UI heparin bolus was injected in all cases. Sheaths were pull-out immediately after the procedure. We used Judkins L 3.5 and Judkins R 4 as first choice catheter. RESULTS: We succeeded in performing a complete coronary angiography in 189 patients (94.5%). In 11 patients the angiography had to be performed or completed by femoral approach: we failed in radial artery puncture in 5 patients; in 2 patients the guidewire could not be advanced beyond brachial bifurcation; in 1 very tall patient the catheter distal extremity did not reach coronary ostia; in 1 case were not able to do selective injection in left coronary ostium because of brachiocephalic trunk tortuosity; in 2 patients resistant radial artery spasm occurred. It was necessary to change the first choice catheter in 17 patients (8.5%) for left coronary artery and in 4 patients (2%) for right coronary artery. Clinical complications were ventricular fibrillation in 1 case and vasovagal reaction in 3 cases. Local complications were mild haematic effusion in 5 cases, small haematomas in 2 cases. In 12 patients radial artery pulsations were not palpable at discharge; in 4 of them radial artery pulse spontaneously reappeared after a week. CONCLUSIONS: Percutaneous transradial approach for coronary angiography is safe and feasible and represents a good alternative entry method mainly in patients with peripheral arteriopathy, in patients treated with anticoagulants and in outpatients coronary angiography.

Adult↗
PubMed1997

Cost-effectiveness of angiography performed during surgery for ruptured intracranial aneurysms.

PURPOSE: To calculate the incremental cost-utility ratio for routine angiography performed during surgery for ruptured cerebral aneurysms. METHODS: Decision-tree and Markov analyses based on a cohort simulation were used to determine the incremental cost-utility ratio of routine intraoperative angiography versus no angiography. Input data from the literature were estimated for the following variables: frequency of unexpected aneurysmal rests and branch artery occlusions; annual rate of rehemorrhage of partially clipped aneurysms; prevalence of clinically relevant infarction resulting from branch artery occlusion; efficacy of clip repositioning; morbidity associated with intraoperative angiography; morbidity and mortality associated with aneurysmal rehemorrhage; sensitivity of intraoperative angiography for aneurysmal rests; and costs of intraoperative angiography, added duration of surgery, ischemic cerebral infarction, aneurysmal rehemorrhage, and rehabilitation. Sensitivity analyses were performed for all relevant input variables. A societal perspective was used, and cost-utility ratios less than $50000/quality-adjusted life years (QALY) gained were considered acceptable. RESULTS: Baseline input variables resulted in an acceptable cost-utility ratio for routine intraoperative angiography ($19000/QALY). The input variables with greatest influence on the cost-utility ratio were frequency of branch artery occlusions, angiographic morbidity, and cost of angiography. However, the cost-utility ratio remained acceptable even over wide ranges of these input variables. Frequency of unexpected partially clipped aneurysms, efficacy of clip repositioning, and costs of stroke, rehemorrhage, and rehabilitation had relatively little impact on the analysis. CONCLUSION: Routine intraoperative angiography is cost-effective if performed in a manner consistent with low morbidity in a patient cohort harboring at least some unexpected branch artery occlusions that, if uncorrected, would result in clinically relevant cerebral infarctions.

Adult↗
PubMed1998

Carotid artery stenosis, occlusion, and pseudo-occlusion: first-pass, gadolinium-enhanced, three-dimensional MR angiography--preliminary study.

PURPOSE: To determine the accuracy of gadolinium-enhanced three-dimensional magnetic resonance (MR) angiography in the evaluation of carotid artery stenosis. MATERIALS AND METHODS: A prospective blinded comparison of first-pass MR angiography with conventional digital subtraction angiography (DSA) was performed in 21 patients suspected of having carotid artery stenosis. MR angiography was performed on a 1.5-T magnet with gradient overdrive equipment, with a coronal radio-frequency-spoiled, three-dimensional, fast low-angle shot sequence after intravenous injection of contrast material. The guidelines of the North America Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection images and conventional angiograms. RESULTS: Grading of stenoses at MR angiography agreed with that at DSA in 92% of the 44 carotid arteries. In the 18 carotid arteries with severe stenosis (70%-99%), agreement was 94%. All internal carotid occlusions (n = 7) or pseudo-occlusions (n = 3) were accurately detected with MR angiography. CONCLUSION: The accuracy of gadolinium-enhanced MR angiography in characterizing the degree of carotid stenosis was high. Findings with MR angiography were accurate for differentiating between occlusion and pseudo-occlusion.

Aged↗
PubMed1998

[Improvement of MRA and 3D-CTA does away with the need for cerebral angiography in many cerebral aneurysm operations].

The purpose of this investigation was to study the indication of cerebral angiography in recent operations for cerebral aneurysms. Cerebral angiography has been used for diagnoses and operations for cerebral aneurysms, but, as the diagnostic procedures such as magnetic resonance angiography (MRA) and three dimensional computed tomographic angiography (3D-CTA) have made remarkable progress, cerebral angiography is not always an indispensable diagnostic tool for cerebral aneurysm operations. One hundred nineteen patients (including 40 patients with ruptured aneurysms) out of 165 patients (including 61 patients with ruptured aneurysms) were diagnosed and operated on following MRA and 3D-CTA. All of these cases of cerebral aneurysms were operated uneventfully without the need for cerebral angiography. We concluded that cerebral angiography is not needed for diagnoses and operations of small common cerebral aneurysms such as middle cerebral artery aneurysms, internal carotid artery-posterior communicating artery aneurysms and anterior communicating artery aneurysms. Cerebral angiography is necessary only in relatively large aneurysms to confirm the dynamic circulation of the cerebral blood flow before operation.

Adult↗
PubMed1994

MR angiography of normal pelvic arteries: comparison of signal intensity and contrast-to-noise ratio for three different inflow techniques.

OBJECTIVE: Two-dimensional (2D) time-of-flight (TOF) MR angiography has been the standard technique for evaluating arteries of the lower extremity. However, this technique is limited by artifacts resulting from vessel pulsation, as well as by relatively poor vessel-to-background contrast. The purpose of this study was to evaluate two cardiac-gated inflow techniques to determine whether they exhibited better contrast and signal performance than the standard technique of 2D TOF MR angiography of the iliac arteries. SUBJECTS AND METHODS: Fourteen subjects who had no clinical evidence of vascular disease had standard 2D TOF, gated 2D TOF, and gated 2D turbo field-echo MR angiography. Images were evaluated for signal-intensity ratio, signal-to-noise ratio, and contrast-to-noise ratio, in addition to qualitative evaluation. RESULTS: Turbo field-echo MR angiography exhibited significantly higher signal-intensity, signal-to-noise, and contrast-to-noise ratios than did either gated or standard MR angiography for all vessel segments. We found no significant difference between gated and standard 2D TOF techniques for any vessel segment. Qualitative features of turbo field-echo MR angiography included improved visualization of horizontal vessel segments compared with the standard 2D TOF technique, less effective venous saturation compared with either the gated or standard 2D TOF technique, and increased ghosting artifacts compared with the gated 2D TOF technique. CONCLUSION: Two-dimensional turbo field-echo MR angiography exhibits improved signal and contrast for evaluation of normal iliac segments compared with standard or gated 2D TOF MR angiography. This technique should replace standard 2D TOF MR angiography for evaluation of the iliac arteries.

Adult↗
PubMed1998

Value of CT angiography for postoperative assessment of patients with iliac artery aneurysms who have received endovascular grafts.

OBJECTIVE: The purpose of the study was to assess the usefulness of CT angiography for follow-up of patients with iliac artery aneurysms who have undergone endovascular treatment. SUBJECTS AND METHODS: Twelve patients with iliac artery aneurysms (10 true aneurysms and two pseudoaneurysms) were examined with CT angiography within 1 week of receiving transfemorally placed endovascular grafts. All patients underwent follow-up CT angiography from 3 to 30 months (mean, 11 months) later. Follow-up CT angiography at 6 months or later (mean, 14 months) was also available in 10 patients. All studies were obtained after i.v. contrast administration using 3-mm collimation, 1.6-2.0 pitch, 2-mm retrospective reconstruction, and with subsequent three-dimensional rendering and multiplanar reformation. The shape and patency of the graft, perigraft thrombosis, and the size of the aneurysm were assessed. RESULTS: All grafts remained patent and without deformity. Complete thrombosis of the aneurysm was shown by initial postoperative CT angiography in 11 patients and confirmed by follow-up studies. A single case of a perigraft leak was revealed by CT angiography and confirmed by follow-up angiography. No aneurysm showed change in size at late follow-up. CONCLUSION: CT angiography is an accurate method for evaluating endovascular devices. CT angiography can be used as a primary technique for follow-up of patients who have undergone endovascular repair of iliac aneurysms.

Aged↗
PubMed2000

Helical CT angiography with maximum intensity projection in the assessment of aortic coarctation after surgery.

OBJECTIVE: The value of CT angiography and three-dimensional (3D) reconstructions was investigated in the postoperative care after surgical repair of aortic coarctation and compared with conventional angiography. SUBJECTS AND METHODS: Twenty-five patients referred because of suspicion of stenosis in the area of former coarctation were prospectively studied with CT angiography and catheter angiography. We determined the morphometric and morphologic findings such as aortic diameter, stenosis, aneurysm, intimal flaps, circumscribed pouch, or arteriosclerotic plaques with 3D reconstructions, using maximum-intensity-projection (MIP) technique and catheter angiography. The results of both techniques were compared. The ratio of the narrowest diameters of the former coarctation and the descending aorta was correlated with the systolic pullback blood pressure gradient in all patients. RESULTS: The former coarctation was normal in 11 patients, (44%), group A; narrowed in 12 children (48%), group B; and dilated in two children (8%), group C. An intimal flap and a circumscribed pouch were delineated in four subjects. MIP reconstructions and catheter angiography revealed identical results regarding the classification into groups A, B, C; intimal flaps; and circumscribed pouches. Statistical analysis revealed good correlation between the narrowest aortic diameters measured on MIP reconstructions and catheter angiography, whereas no correlation between the systolic pullback blood pressure gradient and the diameter ratio of the former coarctation and the descending aorta was found. CONCLUSION: CT angiography and 3D reconstructions using MIP represent a reliable noninvasive technique to replace diagnostic catheter angiography in the postoperative care of patients with coarctation and provide the clinician with valuable information concerning further invasive procedures.

Adolescent↗
PubMed2000

Takayasu arteritis: diagnosis with breath-hold contrast-enhanced three-dimensional MR angiography.

The purpose of the study was to determine the diagnostic accuracy of breath-hold contrast-enhanced three-dimensional (3D) magnetic resonance (MR) angiography in Takayasu arteritis. Thirty patients suspected of having Takayasu arteritis were examined with MR angiography and conventional angiography. Takayasu arteritis was diagnosed in 20 of these patients. MR angiography was performed using a 1.5-T system after bolus injection of 0.1 mmol/kg of gadodiamide. MR angiography clearly depicted various vascular lesions in the aorta and its major branches in all 20 patients with Takayasu arteritis. It also depicted pulmonary artery lesions in 10 (50%) of the 20 patients. MR angiography accurately depicted 323 (98%) of 330 arteries, but 7 (2%) stenotic arteries were overestimated as occluded. The sensitivity and specificity of MR angiography for the diagnosis of Takayasu arteritis were both 100%. Breath-hold contrast-enhanced 3D MR angiography clearly depicts various vascular lesions in both the systemic and pulmonary arteries in Takayasu arteritis, thus allowing a definitive diagnosis of Takayasu arteritis.

Adult↗
PubMedDate not supplied

Relative characteristics of MR angiography and competing vascular imaging modalities.

This article reviews the general characteristics of several vascular imaging modalities with the purpose of identifying the distinguishing features of magnetic resonance (MR) angiography. Brief discussions of conventional x-ray film angiography, intravenous and intraarterial digital subtraction angiography (DSA), duplex and color Doppler flow ultrasound (US), computed tomographic (CT) angiography, transesophageal and intravascular US, angioscopy, and MR angiography are presented. The advantages and disadvantages of each are discussed. The general attributes and image quality features of MR angiography, intraarterial DSA, CT angiography, and US are compared. It is concluded that no single imaging modality will presently suffice for all purposes. Because of its noninvasiveness, rapidly improving image quality, and ability to directly provide velocity information, MR angiography is likely to play a role in an increasing number of clinical applications.

Angiography↗
PubMed2004

CT angiography with three-dimensional techniques for the early diagnosis of intracranial aneurysms. Comparison with intra-arterial DSA and the surgical findings.

INTRODUCTION: Cerebral CT angiography (CTA) is an established method applied to both the detection and treatment planning of intracranial aneurysms. The aim of our study was to compare CTA and digital subtraction angiography (DSA) findings with the surgical results mainly in patients with acute SAH and to evaluate the clinical usefulness of CTA. MATERIALS AND METHODS: During the last 2 years, 82 consecutive patients were admitted under clinical symptoms and signs suggestive of harboring an intracranial aneurysm. CT angiography performed immediately afterwards the plain CT, while DSA was performed within the first 48 h of admission. All aneurysms detected were confirmed during surgery or endovascular embolization. Repeat DSA was performed in all patients having both the initial CTA and the DSA 15 days after the onset of symptoms negative. CT angiograms and conventional angiographies were studied by a consensus of two radiologists for each technique, who performed aneurysm detection, morphological features characterization and evaluation of the technique. RESULTS: Surgical or/and endovascular treatment was performed in 45 patients and 53 aneurysms were confirmed. Using 3D-CT angiography, we detected 47 aneurysms in 42 patients. Conventional angiography depicted 43 aneurysms in 39 patients. The sensitivity of CTA for the detection of all aneurysms versus surgery was 88.7%, the specificity 100%, the positive predictive value (PPV) 100%, the negative predictive value (NPV) 80.7% and the accuracy 92.3%. Accordingly, the sensitivity of DSA was 87.8%, the specificity 98%, the PPV 97.7%, the NPV 89.1% and the accuracy 92.9%. Considering aneurysms > or =3 mm, CTA showed a sensitivity ranging from 93.3 to 100%, equal to that of DSA. CONCLUSION: Cerebral CT angiography has an equal sensitivity to DSA in the detection of intracranial aneurysms >3 mm. It has also 100% detection rate in AcoA and MCA bifurcation aneurysms, while some locations, like posterior communicating artery aneurysms, remain problematic. The delineating features of each aneurysm are better depicted with CTA due to 3D visualization. The use of digital subtraction angiography as a diagnostic tool can be limited in equivocal cases.

Adolescent↗
PubMed1999

Conventional cerebral angiography in children with ischemic stroke.

A retrospective review of conventional cerebral angiograms of 46 children with ischemic stroke was undertaken. Comparison was made with findings on magnetic resonance imaging and magnetic resonance angiography where available. Thirty-six children (78%) underwent magnetic resonance angiography in addition to conventional cerebral angiography. Seven patients had normal cerebral angiograms. Magnetic resonance angiography was diagnostic in 25 of 28 patients with large vessel occlusion, stenosis, or moya-moya syndrome. Conventional angiography was abnormal in four of nine patients with a normal magnetic resonance angiography. All patients with normal conventional angiograms also had normal magnetic resonance angiograms. Conventional angiography, either diagnostic or yielding further information, altered management in five patients with arterial dissection, one patient with large vessel occlusion, one patient with large vessel stenosis, and four patients with arteritis. On the basis of this experience, a clinical algorithm for the use of conventional cerebral angiography in the investigation of ischemic stroke in children is proposed.

Adolescent↗
PubMed2001

Contrast-enhanced moving-table MR angiography: prospective comparison to catheter arteriography for treatment planning in peripheral arterial occlusive disease.

PURPOSE: Prospective comparison of contrast-enhanced moving-table magnetic resonance (MR) angiography to catheter arteriography in endovascular and surgical treatment planning in patients with peripheral arterial occlusive disease. MATERIALS AND METHODS: Thirteen patients scheduled for catheter arteriography for lower extremity arterial occlusive disease underwent contrast-enhanced moving-table MR angiography immediately prior to arteriography. A treatment plan was determined by the vascular surgeon, based on MR angiography, who was blinded to the catheter arteriogram. The treatment plan determined by the MR angiogram was compared to the final treatment plan, which was based on the catheter arteriogram and intraluminal pressure measurements. RESULTS: Treatment plans based on MR angiography and catheter arteriography were identical in 10 of 13 patients (71%). For identifying lesions resulting in intervention, MR angiography had sensitivity of 100% and a positive predictive value of 92%. MR angiography had a treatment specific predictive value of 88% for each lesion identified, and 95% for lesions identified in patients evaluated for claudication. If treatment plans were based on MR angiography only, 46% of patients would have avoided catheter arteriography. CONCLUSION: Contrast-enhanced moving-table MR angiography may be an effective alternative to catheter arteriography in endovascular and surgical treatment planning in selected patients with peripheral arterial occlusive disease, but larger studies are necessary to confirm this.

Adult↗
PubMed1999

[Contrast enhanced MR angiography in the preoperative evaluation of living kidney donors].

PURPOSE: To compare Gadolinium-enhanced MR angiography with conventional DSA in the preoperative evaluation of living kidney donors. MATERIAL AND METHODS: 27 potential living kidney donors were examined with contrast-enhanced MR angiography after conventional angiography. The MR angiograms were evaluated for the number of renal arteries, the presence of early arterial branching and vascular pathologies by two independent readers. The results were compared with those of selective conventional angiography and intraoperative findings. RESULTS: Conventional angiography detected 14 accessory renal arteries. Reader A detected 13 of 14 accessory arteries with no false positive result (sensitivity 93%, specificity 100%). Reader B detected 11 of 14 accessory vessels with one false positive finding (sensitivity 79%, specificity 98%). Early arterial branching was detected by both readers in 9 of 12 vessels with no false positive result (sensitivity 75%, specificity 100%). None of the patients had additional vascular pathology. DISCUSSION: Gadolinium-enhanced MR angiography is a non-invasive alternative to conventional angiography in the preoperative evaluation of living kidney donors. In order to achieve high accuracy in detecting accessory renal arteries and early arterial branching extensive experience with the method and the specific preoperative needs is required. Selective conventional angiography is still superior in detecting very small accessory vessels and early arterial branching.

Adult↗
PubMed1994

[Does indocyanine green angiography aid in deciding indications for laser therapy of exudative senile macular degeneration?].

BACKGROUND: Only a few patients with neovascularized age-related macular degeneration (AMD) have clinical and fluorescein angiographic manifestations that meet eligibility criteria for photocoagulation therapy. Angiography with indocyanine green (ICG) may expand those criteria. MATERIAL AND METHODS: Fifty-two patients with exudative AMD were studied by fluorescein and ICG angiography (using the Rodenstock scanning laser ophthalmoscope). The ICG-angiograms were studied in relation to the questions, how often subretinal neovascularizations (SNV) were visible and how often the results were helpful for laser treatment. RESULTS: In 18 cases (about one third) a SNV was detected by ICG-angiography and in 8 (15%) the result allowed a laser treatment. "Ideal" SNV presented as neovascular trees with a visible feeder-vessel. Other cases showed a circumscribed area of diffuse hyperfluorescence especially in the late phase. Macular edema often prevented the resolution of subretinal membranes. CONCLUSIONS: Only randomised studies will be able to show whether the combination of fluorescein and ICG angiography allows the possibility of treating more patients with SNV than fluorescein angiography alone. In the following circumstances this might be the case: 1. If in subfoveal SNV a feeder-vessel could be delineated with ICG-angiography that might be treated selectively. 2. If an occult SNV might be reclassified as manifest SNV due to findings provided by ICG-angiography. 3. Examination of patients with ICG-angiography immediately after laser photocoagulation might be a way of proving the completeness of the treatment.

Aged↗
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↗
PubMed2001

Coronary magnetic resonance angiography for the detection of coronary stenoses.

BACKGROUND: An accurate, noninvasive technique for the diagnosis of coronary disease would be an important advance. We investigated the accuracy of coronary magnetic resonance angiography among patients with suspected coronary disease in a prospective, multicenter study. METHODS: Coronary magnetic resonance angiography was performed during free breathing in 109 patients before elective x-ray coronary angiography, and the results of the two diagnostic procedures were compared. RESULTS: A total of 636 of 759 proximal and middle segments of coronary arteries (84 percent) were interpretable on magnetic resonance angiography. In these segments, 78 (83 percent) of 94 clinically significant lesions (those with a > or = 50 percent reduction in diameter on x-ray angiography) were also detected by magnetic resonance angiography. Overall, coronary magnetic resonance angiography had an accuracy of 72 percent (95 percent confidence interval, 63 to 81 percent) in diagnosing coronary artery disease. The sensitivity, specificity, and accuracy for patients with disease of the left main coronary artery or three-vessel disease were 100 percent (95 percent confidence interval, 97 to 100 percent), 85 percent (95 percent confidence interval, 78 to 92 percent), and 87 percent (95 percent confidence interval, 81 to 93 percent), respectively. The negative predictive values for any coronary artery disease and for left main artery or three-vessel disease were 81 percent (95 percent confidence interval, 73 to 89 percent) and 100 percent (95 percent confidence interval, 97 to 100 percent), respectively. CONCLUSIONS: Among patients referred for their first x-ray coronary angiogram, three-dimensional coronary magnetic resonance angiography allows for the accurate detection of coronary artery disease of the proximal and middle segments. This noninvasive approach reliably identifies (or rules out) left main coronary artery or three-vessel disease.

Adult↗