ABSTRACT
BACKGROUND AND PURPOSE: Injection rates have attracted scrutiny because of an incident of an aneurysm rupturing during arteriography. We sought to determine the current injection rates for neuroangiography in the setting of aneurysm evaluation. METHODS: An e-mail survey was distributed to 90 neuroradiology program directors within the United States and Canada. The injection rates and total volumes of contrast material injected for the common carotid, internal carotid, and vertebral arteries were provided for an "average" adult individual evaluated for intracranial aneurysms. RESULTS: Sixty-three (70.0%) program directors replied to the survey. Of these, five perform hand injections only and provided approximate values. The mean injection rates (SD) and total volumes (SD) for common carotid arteries were 7.2 cm(3)/s (1.8) and 9.9 cm(3) (2.0), respectively; for internal carotid arteries, 5.8 cm(3)/s (1.4) and 7.9 cm(3) (1.5); and for vertebral arteries, 5.4 cm(3)/s (1.2) and 7.8 cm(3) (1.7). The modes (rate/total) for the common carotid, internal carotid, and vertebral arteries were 7/12, 6/8, and 5/8, respectively. Forty-eight (81.4%) of 59 respondents did not believe a reduction in current injection rates would lead to a diminution in complications of arteriography. CONCLUSION: The rates of injection of contrast material in the United States for neuroradiologic studies show great variability. It does not seem that reducing arteriographic complications is an impetus to reduce injection rates. The values in this survey can provide "industry norms" for injections in the common carotid, internal carotid, and vertebral arteries if these rates are challenged.
Subject(s)
Cerebral Angiography/adverse effects , Contrast Media/administration & dosage , Injections, Intra-Arterial/adverse effects , Intracranial Aneurysm/diagnostic imaging , Canada , Carotid Artery, Common , Carotid Artery, Internal , Contrast Media/adverse effects , Data Collection , Humans , Injections, Intra-Arterial/methods , Subarachnoid Hemorrhage/diagnostic imaging , United States , Vertebral ArteryABSTRACT
SUMMARY: Methylmalonic acidemia is an inborn disorder of amino acid metabolism that commonly presents with neurologic deficits. We present the results of multi-slice proton MR spectroscopy and diffusion-weighted imaging of the brain in two patients with methylmalonic acidemia. The findings consisted of restricted diffusion and elevated lactate in the globi pallidi, compatible with acute infarction (patient 1) and elevated lactate in CSF (patient 2).
Subject(s)
Brain/pathology , Magnetic Resonance Imaging/methods , Magnetic Resonance Spectroscopy , Methylmalonic Acid/blood , Adolescent , Cerebral Infarction/diagnosis , Cerebral Infarction/metabolism , Female , Globus Pallidus/metabolism , Humans , Infant , Lactic Acid/cerebrospinal fluid , Lactic Acid/metabolism , Male , ProtonsABSTRACT
To test the effect of stenosis of the renal artery on the downstream intrarenal blood flow, a snare was placed around the renal artery in 10 dogs and compressed to create stenosis while Doppler curves were obtained from interlobar arteries. Pulsed Doppler examination of the segmental and interlobar arteries was performed by means of placement of a 7.5-MHz mechanical sector transducer directly on the surface of the kidney. The following calculations were made: degree of stenosis (evaluated with aortography), acceleration index (AI) (the acceleration of systole), and resistive index. The Doppler measurements were compared with findings on angiograms. The AI for normal arteries ranged from 2.2 to 4.3, and for arteries with 75% or greater stenosis, from 1.0 to 1.3. Systolic peaks disappeared as near occlusion was achieved. These changes were reversible within seconds of release of the arterial snare. Such change is identical to change in the pulsus tardus and parvus waveforms seen in both acute and chronic severe stenosis of the renal artery in humans.
Subject(s)
Renal Artery Obstruction/physiopathology , Renal Artery/physiopathology , Renal Circulation/physiology , Animals , Dogs , Pulse/physiology , Radiography , Renal Artery/diagnostic imaging , Renal Artery Obstruction/diagnostic imaging , Systole/physiology , Time Factors , Ultrasonography , Vascular Resistance/physiologyABSTRACT
Three patients with portal venous gas (one with radiographic and computed tomographic findings) had similar sonographic and Doppler patterns in the portal vein (PV). These patterns consisted of hyperechogenic foci moving within the lumen of the PV, producing sharp bidirectional spikes superimposed on the usual Doppler tracing of the PV. An injection of 0.25-0.50 cm3 of air, oxygen, nitrogen, and carbon dioxide into the jejunal vein of nine dogs yielded identical portal venous sonographic and Doppler patterns. In addition, the liver parenchyma of the dogs became hyperechogenic after the injection of gas. Gas in the PV is accompanied by the following signs: echogenic, moving foci within the lumen of the PV; sharp spikes on Doppler spectral display; and hyperechogenic foci within the liver parenchyma.
