Intracranial cavernomas: indications for and results of surgery.
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Between April 1991 and April 1997, 46 patients were treated in our department presenting with intracranial cavernomas. Initial symptoms were focal seizures, bleeding episodes, and/or headaches. Mean age was 41 year (range 9 to 68 years). There were 24 female and 22 male patients. Computed tomography and magnetic resonance imaging were performed in order to establish the diagnosis, angiography was only indicated when the hemorrhaged area was so close to the subarachnoid space in the vicinity of the basal cisterns that an aneurysm had to be ruled out. Aggressive indication for surgery also in brainstem cavernomas was based on the natural history of the lesion, since the majority of patients presenting with intracranial bleeding had suffered several (up to six) episodes of previous hemorrhages. Patients' clinical status upon admission and accessibility of the cavernoma were taken into account for planning the operation. The operative planning and approach were greatly facilitated by using a neuronavigational device and intraoperative electrophysiological monitoring particularly in cavernomas located in the brainstem, thalamus, and medulla oblongata. Surgical removal of the lesions resulted in a new permanent neurological deficit only in two patients (4%). These data show that patients benefit from modern neurosurgical techniques in contrast to conservative approach in this disease of rather prolonged natural course. (+info)
Various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke.
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BACKGROUND AND PURPOSE: Various clinical subtypes of patients presenting with sudden-onset ischemic stroke have been recognized, but classification of those types is not simple. We identified various patterns of perfusion-weighted MR imaging and MR angiographic findings in hyperacute ischemic stroke with relation to clinical outcomes. METHODS: Twelve patients with symptoms of acute ischemic stroke due to middle cerebral artery occlusion underwent perfusion-weighted MR imaging and MR angiography within 6 hours after the onset of symptoms. Perfusion-weighted imaging was performed with a conventional dynamic contrast-enhanced T2*-weighted sequence, and cerebral blood volume (CBV) maps were then created. CBV maps and MR angiographic findings were compared with 99mTc-HMPAO brain SPECT scans, short-term outcomes, and follow-up imaging findings. RESULTS: The combined CBV and MR angiographic findings were classified into three patterns: arterial occlusion and decreased CBV (n = 8), arterial occlusion and increased CBV (n = 2), and no arterial occlusion and normal CBV (n = 2). These three patterns were strongly related to SPECT findings, short-term outcomes, and follow-up imaging findings. Perfusion on SPECT decreased markedly in the affected regions in all patients with the first pattern, decreased slightly in the second pattern, and was normal in the third pattern. Symptoms were not significantly changed at 24 hours after onset in any of the patients with the first pattern, but resolved completely in all patients with the latter two patterns. Follow-up imaging showed large infarctions in all patients with the first pattern. Initially, no infarction was seen in the second pattern, but watershed infarction developed later in one of these patients. CONCLUSION: Hyperacute ischemic stroke may be differentiated into three imaging patterns with different clinical outcomes. The combined use of perfusion-weighted MR imaging and MR angiography may play a substantial role in guiding the choice of treatment of this disease. (+info)
3D Ultrasound imaging--a useful non-invasive tool to detect AV fistulas in transplanted kidneys.
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BACKGROUND: A precise, non-invasive, non-toxic, repeatable, convenient and inexpensive follow-up of renal transplants, especially following biopsies, is in the interest of nephrologists. Formerly, the rate of biopsies leading to AV fistulas had been underestimated. Imaging procedures suited to a detailed judgement of these vascular malformations are to be assessed. METHODS: Three-dimensional (3D) reconstruction techniques of ultrasound flow-directed and non-flow-directed energy mode pictures were compared with a standard procedure, gadolinium-enhanced nuclear magnetic resonance imaging angiography (MRA) using the phase contrast technique. RESULTS: Using B-mode and conventional duplex information, AV fistulas were localized in the upper pole of the kidney transplant of the index patient. The 3D reconstruction provided information about the exact localization and orientation of the fistula in relation to other vascular structures, and the flow along the fistula. The MRA provided localization and orientation information, but less functional information. Flow-directed and non-flow-directed energy mode pictures could be reconstructed to provide 3D information about vascular malformations in transplanted kidneys. CONCLUSION: In transplanted kidneys, 3D-ultrasound angiography may be equally as effective as MRA in localizing and identifying AV malformations. Advantages of the ultrasound method are that it is cheaper, non-toxic, non-invasive, more widely availability and that it even provides more functional information. Future prospective studies will be necessary to evaluate the two techniques further. (+info)
Surgical renal artery reconstruction without contrast arteriography: the role of clinical profiling and magnetic resonance angiography.
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PURPOSE: Contrast arteriography is the accepted gold standard for diagnosis and treatment planning in patients with atherosclerotic renovascular disease (RVD). In this study, the results of a selective policy of surgical renal artery reconstruction (RAR) with magnetic resonance angiography (MRA) as the sole preoperative imaging modality are reviewed. METHODS: From May 1993 to May 1998, 25 patients underwent RAR after clinical evaluation, and aortic/renal MRA performed with a gadolinium-enhanced and 3-dimensional phase contrast technique. Clinical presentations suggested severe RVD in all patients and included poorly controlled hypertension (16 patients), hospitalization for hypertensive crises and/or acute pulmonary edema (13), and deterioration of renal function within one year of operation (15). Thirteen patients had associated aortic pathologic conditions (12 aneurysms, 1 aortoiliac occlusive disease), and eight of these patients also underwent noncontrast computed tomography scans. Significant renal dysfunction (serum creatinine level, >/=2.0 mg/dL) was present in all but 4 patients with 14 of 25 patients having extreme (creatinine level, >/=3.0 mg/dL) dysfunction. RESULTS: Hemodynamically significant RVD in the main renal artery was verified at operation in 37 of 38 reconstructed main renal arteries (24/25 patients). A single accessory renal artery was missed by MRA. RAR was comprehensive (bilateral or unilateral to a single-functioning kidney) in 21 of 25 patients and consisted of hepatorenal bypass graft (3 patients), combined aortic and RAR (13 patients), isolated transaortic endarterectomy (8 patients), and aortorenal bypass graft (1 patient). Early improvement in both hypertension control and/or renal function was noted in 21 of 25 patients without operative deaths or postoperative renal failure. Sustained favorable functional results at follow-up, ranging from 5 months to 4 years, were noted in 19 of 25 patients. CONCLUSION: MRA is an adequate preoperative imaging modality in selected patients before RAR. This strategy is best applied in circumstances where the clinical presentation suggests hemodynamically significant bilateral RVD and/or in patients at substantial risk of complications from contrast angiography. (+info)
Intracranial stenoocclusive disease: double-detector helical CT angiography versus digital subtraction angiography.
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BACKGROUND AND PURPOSE: To our knowledge, no large-scale studies comparing the accuracy of CT angiography (CTA) to intraarterial digital subtraction angiography (DSA) of intracranial stenosis have been reported. We attempted to determine the diagnostic value of intracranial CT angiography (CTA) of normal vasculature and variants as well as of stenoocclusive disease. METHODS: One-hundred and twelve patients underwent CTA and intraarterial angiography, and 2205 vascular segments were examined to ascertain presence, visibility, and degree of arterial stenoses (n = 105) as well as anatomic variants. Source, maximum intensity projection (MIP), and MIP-generated multiplanar reformatted (MPR) images were evaluated. RESULTS: All 55 anatomic variants were identified correctly. Visibility of small-vessel segments was increased from 75% to 83% by using source images. MPR was helpful in differentiating distal vertebral hypoplasia from stenosis and in overcoming artifacts. All 43 occlusive segments were graded correctly (sensitivity = 100%, predictive value = 93.4%) as follows: severely stenotic ([n = 23], sensitivity = 78%, predictive value = 81.8%); moderately stenotic ([n = 36], sensitivity = 61%, predictive value = 84.6%); and mildly stenotic ([n = 3], sensitivity = 66%, predictive value = 28%). Normal segments (n = 2100) had a sensitivity of 99.5%, and CTA evinced a specificity of 99% for detecting stenoocclusive disease. Approximately one-third of wrong assessments were related to the petrous segment of the carotid artery. CONCLUSION: CTA with double-detector technology and advanced postprocessing algorithms, including MPR, is about as reliable as MRA in depicting the vasculature of the anterior and posterior circulation and in grading intracranial stenoocclusive lesions, with the exception of the petrous segment of the carotid artery. CTA might be superior to MRA in the evaluation of poststenotic low-flow segments. (+info)
BACKGROUND: Three-dimensional (3D) navigator-gated and prospectively corrected free-breathing coronary magnetic resonance angiography (MRA) allows for submillimeter image resolution but suffers from poor contrast between coronary blood and myocardium. Data collected over >100 ms/heart beat are also susceptible to bulk cardiac and respiratory motion. To address these problems, we examined the effect of a T2 preparation prepulse (T2prep) for myocardial suppression and a shortened acquisition window on coronary definition. METHODS AND RESULTS: Eight healthy adult subjects and 5 patients with confirmed coronary artery disease (CAD) underwent free-breathing 3D MRA with and without T2prep and with 120- and 60-ms data-acquisition windows. The T2prep resulted in a 123% (P<0. 001) increase in contrast-to-noise ratio (CNR). Coronary edge definition was improved by 33% (P<0.001). Acquisition window shortening from 120 to 60 ms resulted in better vessel definition (11%; P<0.001). Among patients with CAD, there was a good correspondence with disease. CONCLUSIONS: Free-breathing, T2prep, 3D coronary MRA with a shorter acquisition window resulted in improved CNR and better coronary artery definition, allowing the assessment of coronary disease. This approach offers the potential for free-breathing, noninvasive assessment of the major coronary arteries. (+info)
Visualization and functional assessment of proximal and middle left anterior descending coronary stenoses in humans with magnetic resonance imaging.
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BACKGROUND: Coronary artery bypass grafting improves survival in patients with >70% luminal diameter narrowing of the 3 major epicardial coronary arteries, particularly if there is involvement of the proximal portion of the left anterior descending (LAD) coronary artery. Measurement of coronary flow reserve can be used to identify functionally important luminal narrowing of the LAD artery. Although magnetic resonance imaging (MRI) has been used to visualize coronary arteries and to measure flow reserve noninvasively, the utility of MRI for detecting significant LAD stenoses is unknown. METHODS AND RESULTS: Thirty subjects (23 men, 7 women, age 36 to 77 years) underwent MRI visualization of the left main and LAD coronary arteries as well as measurement of flow in the proximal, middle, or distal LAD both at rest and after intravenous adenosine (140 microgram/kg per minute). Immediately thereafter, contrast coronary angiography and when feasible, intracoronary Doppler assessments of coronary flow reserve, were performed. There was a statistically significant correlation between MRI assessments of coronary flow reserve and (a) assessments of coronary arterial stenosis severity by quantitative coronary angiography and (b) invasive measurements of coronary flow reserve (P<0.0001 for both). In comparison to computer-assisted quantitative coronary angiography, the sensitivity and specificity of MRI for identifying a stenosis >70% in the distal left main or proximal/middle LAD arteries was 100% and 83%, respectively. CONCLUSIONS: Noninvasive MRI measures of coronary flow reserve correlated well with similar measures obtained with the use of intracoronary Doppler flow wires and predicted significant coronary stenoses (>70%) with a high degree of sensitivity and specificity. MRI-based measurement of coronary flow reserve may prove useful for identification of patients likely to obtain a survival benefit from coronary artery bypass grafting. (+info)
Migraine complicated by brachial plexopathy as displayed by MRI and MRA: aberrant subclavian artery and cervical ribs.
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This article describes migraine without aura since childhood in a patient with bilateral cervical ribs. In addition to usual migraine triggers, symptoms were triggered by neck extension and by arm abduction and external rotation; paresthesias and pain preceded migraine triggered by arm and neck movement. Suspected thoracic outlet syndrome was confirmed by high-resolution bilateral magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the brachial plexus. An unsuspected aberrant right subclavian artery was compressed within the scalene triangle. The aberrant subclavian artery splayed apart the recurrent laryngeal and vagus nerves, displaced the esophagus anteriorly, and effaced the right stellate ganglia and the C8-T1 nerve roots. Scarring and fibrosis of the left scalene triangle resulted in acute angulation of the neurovascular bundle and diminished blood flow in the subclavian artery and vein. A branch of the left sympathetic ganglia was displaced as it joined the C8-T1 nerve roots. Left scalenectomy and rib resection confirmed the MRI and MRA findings; the scalene triangle contents were decompressed, and migraine symptoms subsequently resolved. (+info)