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PubMedDate not supplied

Comparison of interstudy reproducibility of equilibrium electrocardiography-gated SPECT radionuclide angiography versus planar radionuclide angiography for the quantification of global left ventricular function.

BACKGROUND: Electrocardiography-gated single photon emission computed tomography (SPECT) radionuclide angiography (RNA) provides accurate measurement of both left ventricular (LV) ejection fraction (EF) and end-diastolic and end-systolic volumes. In this study we studied the interstudy precision and reliability of SPECT RNA as compared with planar RNA for the measurement of global systolic LV function. METHODS AND RESULTS: The population included 10 patients with chronic coronary artery disease having 2 sets of acquisitions, each consisting of planar and SPECT RNA. SPECT RNA was processed with SPECT-QBS and SPECT-35%. (For SPECT-35%, a manual segmentation method based on the 35% threshold of the maximum LV cavity activity is used to provide estimates of the number of voxels and the activity included in the LV cavity. The calculated LV number of voxels is then used to calculate LV volume measurement. The LV EF is calculated as the ratio of LV end-diastolic and end-systolic activity.) For LV EF, end-diastolic volume, and end-systolic volume, the interstudy precision, as reflected by the correlation coefficient, coefficient of variability, coefficient of repeatability, and within-subject coefficient of variation, and the interstudy reliability, as reflected by the intraclass correlation coefficient, were best with SPECT-35%, followed by planar RNA and then SPECT-QBS, respectively. The sample size needed to objectify a change in a parameter of LV function is lowest with SPECT-35%, followed by planar RNA and then SPECT-QBS, respectively. CONCLUSIONS: The SPECT-35% processing method provides excellent interstudy precision and reliability for LV function measurement. In this aspect it seems to be better than planar RNA and SPECT-QBS. These results need to be confirmed in a larger patient population.

Coronary Artery Disease↗
PubMed1999

3-D power Doppler cerebral angiography in neonates and young infants: comparison with 2-D power Doppler angiography.

The aims of this study were to evaluate the ability of 3-dimensional (3-D) power Doppler angiography (3DPDA) to depict the intracranial vasculature in infants, to compare with 2-D power Doppler ultrasonography (2DPDU), and to explore the potential clinical applications of this procedure in young infants with brain disorders. We performed 3DPDA in 27 infants. 2DPDU were completed in both sagittal and coronal directions in 12 of these patients. In the other 15, only right sagittal plane images were available for comparison. Using a grading system and with only vessels with more than half of the length demonstrated included for comparison, we compared the Doppler signals of major vessels. 3DPDA could have good visualization in more than 60% of the internal carotid artery, ophthalmic artery, pericallosal artery, callosomarginal artery, internal cerebral vein, vein of Galen, and straight sinus in the sagittal plane. 3DPDA also could have good demonstration in about 50% of basilar artery in coronal plane, and posterior communicating artery, posterior cerebral artery, and lenticulostriate artery in sagittal plane. 3DPDA was better than 2DPDU in demonstrating all the major intracranial vessels in different planes, except the anterior communicating artery. In the anterior communicating artery, neither can demonstrate more than 30%.

Brain Diseases↗
PubMed1992

[Magnetic resonance angiography with gadolinium (Gd-DTPA) versus baseline magnetic resonance angiography in the study of the intracranial circulation].

The authors evaluated the role of GdDTPA in magnetic resonance angiography (MRA) of intracranial vessels. Fifteen patients affected with different conditions underwent MRA of intracranial vessels before and after paramagnetic contrast medium infusion. A superconductive 1.5-T magnet (Magnetom Siemens) was used, and a head circular coil, together with the 3DFT TOF technique. The enhanced exam was performed following the infusion of 0.2 ml/kg of GdDTPA in about 2 minutes, with simultaneous MRA image acquisition. To compare enhanced with unenhanced images relative to signal intensity, the signal increase at the basilar artery and carotid sinus was studied, together with signal-to-noise (S/N) ratio and spatial resolution. During acquisition, enhanced MRA images at the basilar artery showed a mean intensity value of 423.8 +/- 33.2 vs 357.8 +/- 53.2 of unenhanced scans; a statistically significant difference (p < 0.05; p < 0.01) was observed in favor of enhanced images. At the carotid sinus, enhanced MRA showed 184.5 +/- 28.4 mean intensity value vs 190.5 +/- 19.8 of unenhanced exams; no statistically significant difference was observed (p < 0.05; p < 0.01) in favor of unenhanced exams. At the basilar artery the S/N ratio of baseline exams was 1.9 vs 2.2 for enhanced scans; at the carotid sinus S/N ratio was 2.4 (unenhanced) vs 2.3 (enhanced). Thus, MRA allowed better visualization of peripheral branches of arterial (95.6%) and venous vessels, which unenhanced scans always failed to depict; on the other hand, enhanced images exhibited poorer definition of arterial vessels which were never isolated from the background. The simultaneous visualization of arterial and venous vessels, of choroid plexus and mucosae, affect the quality of enhanced angiograms. At present, GdDTPA is the sole contrast medium suitable for MRA intracranial vessels even though, due to its pharmacokinetic features, it is not the optimum medium.

Adult↗
PubMed1985

A comparison of angiography, intravenous digital subtraction angiography and duplex ultrasound in the diagnosis of carotid artery atherosclerosis.

Duplex ultrasonography and intravenous digital subtraction angiography (IV-DSA) were used as the initial diagnostic studies in 124 patients referred for evaluation of neurological disorders possibly related to carotid bifurcation disease in the neck. Conventional angiograms were subsequently performed in 29 patients. Diagnostic images were obtained in 100% of the angiograms, 94% of the duplex ultrasonograms and 89% of the IV-DSA studies. Using the angiogram as the reference standard for plaque detection, duplex ultrasonography had a sensitivity of 0.93 and specificity of 0.83. Doppler velocity ratio alone was used to detect all patients with angiographically demonstrated disease but demonstrated a specificity of only 0.35. IV-DSA showed a sensitivity of 0.93 and specificity of 0.91. IV-DSA and duplex ultrasonography agreed in the assessment of degree stenosis in over 90% of cases and we conclude that these two modalities have approximately the same sensitivity and specificity for detecting atherosclerotic disease at the carotid bifurcations.

Adult↗
PubMed1985

[Phase and amplitude images using Fourier analysis in radioisotopic angiography. Comparison with contrast angiography for studying regional changes in ventricular contraction].

Phase-amplitude images and phase distribution histograms, derived from a temporal Fourier analysis of equilibrium ecg-gated blood pool studies, were used to assess the overall wall motion synchronism and to detect regional wall motion abnormalities in 69 consecutive patients with suspected or documented coronary artery disease, in whom biplane contrast left ventriculography and coronary angiography were performed. Four regions were considered on the 15 degrees caudal left-anterior oblique view radionuclide image, in order to identify the 7 conventional angiographic left ventricular wall segments (as the American Heart Association Council of Cardiovascular Surgery). Regional abnormalities on the phase-amplitude images from the 15 degrees caudal left anterior oblique view scans were studied in order to identify local hypokinesis, akinesis or dyskinesis (in accord to definitions used for contrast cineangiography) relative to seven conventional left ventricular wall segments. Results of phase-amplitude image analysis were compared with those of contrast cineangiography. The parametric images showed overall sensitivity of 82% and 92% respectively towards biplane and monoplane (left anterior oblique) contrast cineangiography, with a high degree of specificity (97%). Most akinetic and dyskinetic segments were correctly identified. A significant phase delay (greater than or equal to 70 degrees) from mean value, always occurred in dyskinetic segments and generally related to the severity of the wall motion abnormality. Lower accuracy was observed for hypokinetic regions; sensitivity was lower for apical and antero-lateral segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Carotid bifurcation: angiography with magnetic resonance versus carotid angiography].

The reliability of Magnetic Resonance Angiography (MRA) was investigated in the study of stenosis and obstruction of carotid bifurcation; digital carotidography was the gold standard. Twenty-five consecutive patients with clinical suspicion of cerebrovascular insufficiency entered the study. MRA was performed with a 1.5 T superconductive magnet (Magnetom Siemens) and a linear head coil. The TOF 3D (FA 20 degrees, TR 30 ms, TE 7 ms) technique was applied. Images were acquired on the sagittal plane and rotated in postprocessing according to MIP on the z axis from 60 to 120 degrees (step 5). MRA exhibit 80.5% sensitivity, 96% specificity, 89.4% accuracy, 94.7% positive predictive value and 86.3% negative predictive value. When calculating the interrupted flow relative to hemodynamically significant stenoses (range 31%-occlusions), MRA sensitivity was 80.5%, specificity 100%, negative predictive value 86.3%, positive predictive value 94.7% and overall diagnostic accuracy 91.2%. MRA is to be considered a diagnostically reliable procedure in the study of carotid bifurcation and its diagnostic accuracy may even be increased in the future by the possible assessment of over- and underestimated cases.

Adult↗
PubMed1990

A hematologist's view of contrast media, clotting in angiography syringes and thrombosis during coronary angiography.

While ionic contrast media (CM) are stronger anticoagulants and antiplatelet agents, both nonionic and ionic CM retard clotting, fibrinopeptide A generation and platelet aggregation (at least by Born-O'Brien aggregometry). Thus, nonionic CM do not cause clots and thrombi. Rather, the driving force for clot or thrombus formation, when it occurs, is blood contact with and activation by the foreign surface of a syringe or catheter itself. A marked enhancement of clotting by glass syringes in comparison to plastic ones supports this view. Blood in any syringe or catheter, therefore, will clot more slowly in the presence of nonionic or ionic CM, the inhibitory effects of the latter being more profound. With respect to models of thrombosis at sites of vascular injury or stenosis, the antithrombotic effects of CM may either be transient owing to the dynamic nature of blood flow (local endothelial cell denudation model), or as in the case of ionic CM, actually to enhance local platelet aggregation (stenosis model). In these situations, preservation of the antithrombotic functions of endothelium with nonionic CM may be quite critical.

Angiography↗
PubMed2001

Comparison of contrast enhanced MR-angiography-MRI and digital subtraction angiography in the evaluation of pancreas and/or kidney transplantation patients: initial experience.

To evaluate whether combined contrast enhanced MRA and MRI (ce-MRA-MRI) has the potential to replace intra-arterial DSA (i.a.DSA) in patients with impaired graft function or suspected of vascular complications after pancreas and/or kidney transplantation. 7 patients after combined pancreas-kidney and 22 patients after kidney transplantation underwent ce-MRA-MRI and i.a.DSA within a 3 days interval. Qualitative and quantitative comparison of the arterial and venous supply, the parenchyma and urinary collecting system was made. Both ce-MRA and i.a.DSA showed good results in the detection of arterial stenoses. However, ce-MRA falsely suggested stenoses if vascular clips were used; on the other hand, i.a.DSA was less informative if the graft arteries were very tortuous. Ce-MRA was superior in depicting the venous anatomy (p < 0.001) and the parenchymal enhancement of the pancreatic grafts. For the assessment of the contrast excretion, the pyelocalyceal system and the ureter of the renal graft ce-MRA-MRI was superior (p < 0.001), for small caliber arteries in the renal grafts i.a.DSA was of greater value (p < 0.001). The combination of ce-MRA and MRI is reliable for evaluating the vascular anatomy and has several advantages over i.a.DSA after pancreas and/or kidney transplantation. It can replace i.a.DSA in patients with impaired graft function or suspected of vascular complications after pancreas and/or kidney transplantation.

Adult↗
PubMed2001

Newer diagnostic modalities for pulmonary embolism. Pulmonary angiography using CT and MR imaging compared with conventional angiography.

CTPA is a highly sensitive and excellent primary method for evaluating patients with symptoms of PE. Ongoing studies will demonstrate the good clinical outcome of patients with negative CTPA results. The ability to visualize the lung parenchyma in addition to the pulmonary vasculature, and the smaller number of nondiagnostic scans, make CT more cost effective than V/Q scans, and CT therefore should be used as a first-line evaluation. MR imaging is a continually developing modality with more imaging options that could make it an invaluable or adjunctive test in the near future.

Algorithms↗