Investigation by perfusion CT and diffusion-weighted MR imaging.
Explore the source record for details and available documents.
Cerebrovascular Circulation↗
Biomedical subjects
Max Wintermark
Publications and source records attributed to Max Wintermark.
Correlation of early dynamic CT perfusion imaging with whole-brain MR diffusion and perfusion imaging in acute hemispheric stroke.
BACKGROUND AND PURPOSE: Compared with MR imaging, dynamic CT perfusion imaging covers only a fraction of the whole brain. An important assumption is that CT perfusion abnormalities correlate with total ischemic volume. The purpose of our study was to measure the degree of correlation between abnormalities seen on CT perfusion scans and the volumes of abnormality seen on MR diffusion and perfusion images in patients with acute large-vessel stroke. METHODS: Fourteen patients with acute hemispheric stroke symptoms less than 12 hours in duration were studied with single-slice CT perfusion imaging and multislice MR diffusion and perfusion imaging. CT and MR perfusion studies were completed within 2.5 hours of one another (mean, 77 minutes) and were reviewed independently by two neuroradiologists. Hemodynamic parameters included cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Extents of abnormality on images were compared by using Kendall correlation. RESULTS: Statistically significant correlation was found between CT-CBF and MR-CBF abnormalities (tau = 0.60, P =.003) and CT-MTT and MR-MTT abnormalities (tau = 0.65, P =.001). Correlation of CT-CBV with MR-CBV approached significance (tau = 0.39, P =.06). Extent of initial hyperintensity on diffusion-weighted images correlated best with extent of MR-CBV abnormality (tau = 0.69, P =.001), extent of MR-MTT abnormality (tau = 0.67, P =.002), and extent of CT-CBV abnormality (tau = 0.47, P =.02). CONCLUSION: Good correlation was seen between CT and MR for CBF and MTT abnormalities. It remains uncertain whether CT perfusion CBV abnormalities correspond well to whole-brain abnormalities.
Acute Disease↗
Traumatic injuries: role of imaging in the management of the polytrauma victim (conservative expectation).
Abdominal US and CT play an important role in the initial management of blunt trauma in adults. Ultrasound is an excellent method for detection of free intra-abdominal fluid. It is the modality of choice for initial screening and enables selection of hemodynamically unstable trauma victims with severe hemoperitoneum for immediate surgery. However, even in experienced hands, US is not sufficient to rule out organ injuries reliably. Computed tomography, and particularly multislice CT (MSCT), has several major advantages over US and is currently unsurpassed for the detection of blunt visceral injuries in the abdomen. Computed tomography has a high sensitivity for the detection of parenchymal splenic and hepatic injuries. Injuries of the gastrointestinal tract may be detected with good sensitivity provided that adequate examination technique and careful diagnostic interpretation are combined. The value of CT-based injury-grading systems for predicting the outcome of conservative treatment remains unproven; however, demonstration of direct vascular injuries with CT, e.g., the intrasplenic "contrast blush" sign, may indicate a high likelihood that conservative treatment will fail, thus warranting angiographic embolization or surgery. Monitoring of conservatively treated trauma victims by means of repeat CT studies enables early detection of a variety of delayed, clinically silent complications of trauma, e.g., posttraumatic biloma or bowel devascularization. Catheter angiography may be reserved to selected cases with vascular injuries proven on CT.
Abdominal Injuries↗
Traumatic injuries: organization and ergonomics of imaging in the emergency environment.
Management of trauma patients relies on a simple but obvious concept: Time is life! This is a challenge to the emergency radiologist in his evaluation of the radiological admission survey of severe trauma patients, since the latter need a quick and thorough survey of craniocerebral, cervical, thoracic, abdominal, and limb lesions. This article reviews the architectural design and the management strategies required to fulfill this purpose. Whereas plain films and ultrasonography have precise but limited indications, multislice spiral CT (MSCT) shows an increasingly preponderant role in the imaging evaluation of trauma patients, as demonstrated through three examples (aortic, spine, and craniocerebral trauma). Multislice CT affords a comprehensive assessment of trauma patients' injuries and allows for their categorization according to the severity of traumatic lesions. With respect to the MSCT data volume, the emergency radiologists have to modify the strategies in their examination reading and result transmission, with a growing role attributed to two- and three-dimensional reconstructions. The emergency radiologist's role is thus of prime importance in the management of trauma patients, and this all the more so since development of interventional radiology affords therapeutic procedures alternative to surgery. Trauma radiology and emergency radiology on the whole will assert themselves as consistent and thorough areas of subspecialization.
Algorithms↗
Prognostic accuracy of cerebral blood flow measurement by perfusion computed tomography, at the time of emergency room admission, in acute stroke patients.
The purpose of this study was to determine the prognostic accuracy of perfusion computed tomography (CT), performed at the time of emergency room admission, in acute stroke patients. Accuracy was determined by comparison of perfusion CT with delayed magnetic resonance (MR) and by monitoring the evolution of each patient's clinical condition. Twenty-two acute stroke patients underwent perfusion CT covering four contiguous 10mm slices on admission, as well as delayed MR, performed after a median interval of 3 days after emergency room admission. Eight were treated with thrombolytic agents. Infarct size on the admission perfusion CT was compared with that on the delayed diffusion-weighted (DWI)-MR, chosen as the gold standard. Delayed magnetic resonance angiography and perfusion-weighted MR were used to detect recanalization. A potential recuperation ratio, defined as PRR = penumbra size/(penumbra size + infarct size) on the admission perfusion CT, was compared with the evolution in each patient's clinical condition, defined by the National Institutes of Health Stroke Scale (NIHSS). In the 8 cases with arterial recanalization, the size of the cerebral infarct on the delayed DWI-MR was larger than or equal to that of the infarct on the admission perfusion CT, but smaller than or equal to that of the ischemic lesion on the admission perfusion CT; and the observed improvement in the NIHSS correlated with the PRR (correlation coefficient = 0.833). In the 14 cases with persistent arterial occlusion, infarct size on the delayed DWI-MR correlated with ischemic lesion size on the admission perfusion CT (r = 0.958). In all 22 patients, the admission NIHSS correlated with the size of the ischemic area on the admission perfusion CT (r = 0.627). Based on these findings, we conclude that perfusion CT allows the accurate prediction of the final infarct size and the evaluation of clinical prognosis for acute stroke patients at the time of emergency evaluation. It may also provide information about the extent of the penumbra. Perfusion CT could therefore be a valuable tool in the early management of acute stroke patients.
Acute Disease↗
MR pattern of hyperacute cerebral hemorrhage.
Magnetic resonance (MR) pattern of cerebral hemorrhage relates mainly to the relaxation and susceptibility effects of iron-containing hemoglobin degradation products, as well as to their intra- or extracellular location. The purpose of this article is to report two acute stroke patients who underwent thrombolytic therapy and developed hyperacute cerebral hemorrhage during their admission cerebral MR survey. They constitute the earliest MR appearance of hyperacute intracerebral bleeding reported in the literature, featuring increased diffusion properties and persistent susceptibility effect on perfusion-weighted imaging (PWI)-series.
Aged↗
Intraluminal aortic fat as an unusual presentation of blunt traumatic aortic rupture.
Explore the source record for details and available documents.
Accidents, Traffic↗
CT perfusion scanning with deconvolution analysis: pilot study in patients with acute middle cerebral artery stroke.
PURPOSE: To measure mean cerebral blood flow (CBF) in ischemic and nonischemic territories and in low-attenuation regions in patients with acute stroke by using deconvolution-derived hemodynamic imaging. MATERIALS AND METHODS: Twelve patients with acute middle cerebral artery stroke and 12 control patients were examined by using single-section computed tomography (CT) perfusion scanning. Analysis was performed with a deconvolution-based algorithm. Comparisons of mean CBF, cerebral blood volume (CBV), and mean transit time (MTT) were determined between hemispheres in all patients and between low- and normal-attenuation regions in patients with acute stroke. Two independent readers examined the images for extent of visually apparent regional perfusion abnormalities. The data were compared with extent of final infarct in seven patients with acute stroke who underwent follow-up CT or magnetic resonance imaging. RESULTS: Significant decreases in CBF (-50%, P =.001) were found in the affected hemispheres of patients with acute stroke. Significant changes in CBV (-26%, P =.03) and MTT (+111%, P =.004) were also seen. Significant alterations in perfusion were also seen in low- compared with normal-attenuation areas. Pearson correlation between readers for extent of CBF abnormality was 0.94 (P =.001). Intraobserver variation was 8.9% for CBF abnormalities. CONCLUSION: Deconvolution analysis of CT perfusion data is a promising method for evaluation of cerebral hemodynamics in patients with acute stroke.
Adult↗
Imaging of acute traumatic injuries of the thoracic aorta.
Blunt traumatic aortic injuries are a major concern in the settings of high-speed deceleration accidents, since they are associated with a very high mortality rate; however, with prompt diagnosis and surgery, 70% of the patients with a blunt aortic lesion who reach the hospital alive will survive. This statement challenges the emergency radiologist in charge to evaluate the admission radiological survey in a severe chest trauma patient. With a 95% negative predictive value for the identification of blunt traumatic aortic lesions, plain chest film represents an adequate screening test. If aortography remains the gold standard, it tends, at least in hemodynamically stable trauma patients, to be replaced by spiral-CT angiography (SCTA), which demonstrates a 96.2% sensitivity, a 99.8% specificity, and a 99.7% accuracy. In unstable patients, trans-esophageal echography (TEE) plays a major diagnostic role. Knowledge of advantages and pitfalls of these imaging techniques, as reviewed in this article, will help the emergency radiologist to choose the appropriate algorithm in the diagnosis of traumatic aortic injury, for each trauma patient.
Acute Disease↗
Unilateral putaminal CT, MR, and diffusion abnormalities secondary to nonketotic hyperglycemia in the setting of acute neurologic symptoms mimicking stroke.
A 75-year-old Asian man presented with two episodes of chorea associated with nonketotic hyperglycemia. His chorea rapidly resolved after restitution of a normal serum glucose level, although an MR image obtained at the time of acute symptoms demonstrated high signal intensity on T1-weighted images, low signal intensity on T2-weighted images, and restricted diffusion, all involving the left putamen. A CT scan obtained 1 month later demonstrated faint hyperattenuation of the involved putamen. The reported pathophysiologic considerations for these imaging features are reviewed, and an original explanation is proposed.
Aged↗