ABSTRACT
BACKGROUND: Drug handling in paediatric intensive care units (PICU) is prone to medication errors. We aimed to identify type and prevalence of those errors and to assess preventative interventions. METHODS: Prospective intervention study investigating a 3-step intervention for preventing errors in drug handling in a 10-bed PICU of a university hospital. Nurses' drug handling was monitored in daily routine to identify the number of patients affected by errors and overall prevalence and types of errors in drug handling. We implemented a comprehensive intervention consisting of an information handout, a training course, and a 76-page reference book tailored to reduce the prevalence. RESULTS: The prevalence of errors in drug handling decreased from 83 % (555 errors/668 processes)to 63 % (554/883; p < 0.001) after the intervention. The number of affected patients remained unchanged (95 % vs. 89 %, p = 0.370).Peroral (PO) drugs (1.33 errors/process) were more error-prone than intravenous (IV) drugs(0.64), despite being used less frequently (27 % vs.73 % of all processes, p < 0.001). The interventions decreased the prevalence to 0.77 errors/process(p < 0.001) in PO and to 0.52 in IV drugs (p = 0.025). CONCLUSION: Errors in drug handling were alarmingly frequent. PO drugs were frequently subject to errors, even though being used less frequently. The implementation of a comprehensive intervention succeeded in reducing the prevalence of errors. Yet further refinements are necessary to decrease also the number of affected patients.
Subject(s)
Critical Care Nursing/methods , Intensive Care Units, Pediatric , Medication Errors/prevention & control , Medication Systems, Hospital/organization & administration , Administration, Oral , Child , Critical Care Nursing/education , Critical Care Nursing/organization & administration , Critical Care Nursing/statistics & numerical data , Cross-Sectional Studies , Hospitals, Pediatric/organization & administration , Hospitals, Pediatric/statistics & numerical data , Hospitals, University/organization & administration , Hospitals, University/statistics & numerical data , Humans , Infusions, Intravenous/nursing , Infusions, Intravenous/statistics & numerical data , Inservice Training , Intensive Care Units, Pediatric/statistics & numerical data , Medication Errors/statistics & numerical data , Medication Systems, Hospital/statistics & numerical data , Prospective Studies , Surveys and QuestionnairesABSTRACT
High-dose chemotherapy followed by autologous stem cell transplantation has been shown to be feasible and highly effective in newly diagnosed primary central nervous system lymphoma. In this retrospective multicenter study, we investigated prognosis and baseline risk factors in patients with primary central nervous system lymphoma who underwent this treatment approach. We retrospectively analyzed 105 immunocompetent patients with primary central nervous system lymphoma who underwent high-dose chemotherapy followed by autologous stem cell transplantation with or without whole brain radiotherapy as first-line consolidation treated at 12 German centers between 1997 and 2011. We estimated survival rates and investigated the impact of age, performance status, serum lactate dehydrogenase level, and deep brain involvement on overall and progression-free survival. Patients were additionally categorized into three prognostic groups according to the Memorial Sloan Kettering Cancer Center prognostic model. After a median follow up of 47 months, median progression-free survival and overall survival was reached after 85 and 121 months; 2- and 5-year survival rates were 82% and 79%, respectively. The Memorial Sloan Kettering Cancer Center prognostic model did not predict survival. Only age revealed some evidence of prognostic relevance. Overall response rate was 95%; of those patients with progressive disease before high-dose chemotherapy, 7 of 20 achieved ongoing complete remission after therapy without whole brain radiation therapy. Transplantation-associated mortality was 2.8%. High-dose chemotherapy followed by autologous stem cell transplantation is a highly effective and safe treatment modality for selected primary central nervous system lymphoma patients. Superiority compared to standard chemotherapy still warrants further investigation.
Subject(s)
Central Nervous System Neoplasms/mortality , Lymphoma/mortality , Adult , Aged , Antineoplastic Agents/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Central Nervous System Neoplasms/therapy , Combined Modality Therapy , Female , Hematopoietic Stem Cell Transplantation , Humans , Lymphoma/therapy , Male , Middle Aged , Prognosis , Radiotherapy , Retrospective Studies , Risk Factors , Transplantation, Autologous , Treatment Outcome , Young AdultABSTRACT
BACKGROUND: Previously, endovascular treatment of wide-necked aneurysms and stenosis involving small vessels measuring <2 mm in diameter was limited. There are no reports in the literature addressing stent placement in small distal cerebral vessels. Recent experience with the Neuroform stent has shown that this device can be safely and effectively used to treat aneurysms in vessels of this caliber. MATERIALS AND METHODS: We report 8 cases of Neuroform stent placement into cerebral vessels measuring <2 mm in diameter (range, 1.1-1.8 mm). All stents were placed for aneurysm treatment in conjunction with coiling. Lesion locations and number were as follows: anterior communicating artery region (n = 5), pericallosal artery A2-A3 (n = 1), middle cerebral artery (MCA) M1-M2 (n = 1), and MCA M3-M4 (n = 1). Clinical follow-up ranged from 4.5 to 18 months. Imaging follow-up was performed with MR imaging/MR angiography. RESULTS: All procedures were successfully performed without immediate or delayed device-related complications. Intraprocedural thrombus developed within the stent in 2 patients and immediately resolved with 10 mg of intra-arterial abciximab. Follow-up at 18 months demonstrated durable results. There were no clinical neurologic symptoms related to the treated vessel territory at follow-up. CONCLUSION: Development of newer low-profile endovascular devices allows access and ability to treat lesions farther out in the smaller cerebral vessels. We have safely and successfully treated 8 vessels smaller than 2 mm in diameter with newer self-expanding stents with good short- and intermediate-term results. Further follow-up and more experience are necessary to determine long-term results.
Subject(s)
Embolization, Therapeutic/instrumentation , Intracranial Aneurysm/therapy , Stents , Aged , Cerebral Angiography , Embolization, Therapeutic/adverse effects , Embolization, Therapeutic/methods , Female , Follow-Up Studies , Humans , Intracranial Aneurysm/diagnostic imaging , Male , Middle Aged , Retrospective Studies , Treatment OutcomeABSTRACT
BACKGROUND AND PURPOSE: The canine vein pouch aneurysm model is widely used for testing and development of devices directed at the endovascular treatment of aneurysms. Our purpose was to determine the incidence of spontaneous thrombosis and rupture of these aneurysms. MATERIALS AND METHODS: A retrospective review of laboratory records of canine vein pouch aneurysms made during a 6-year period was performed. The aneurysm and parent artery dimensions as well as incidences of spontaneous thrombosis and rupture were noted. RESULTS: During the interval studied, 326 vein patch aneurysms were made in 310 canines. Of these, 102 were sidewall (lateral) and 224 were bifurcation aneurysms. Spontaneous occlusion occurred in 9 of the sidewall aneurysms and in only 1 of the bifurcation aneurysms. None of the aneurysms ruptured. CONCLUSION: Spontaneous occlusion of the sidewall canine vein patch aneurysm occurred less than 10% of the time; in the bifurcation aneurysms, it almost never occurred. These characteristics enhance the value of this model for use in testing of devices intended for the endovascular treatment of aneurysms.
Subject(s)
Aneurysm/epidemiology , Aneurysm/therapy , Disease Models, Animal , Dogs , Embolization, Therapeutic , Aneurysm/diagnostic imaging , Aneurysm, Ruptured/epidemiology , Angiography, Digital Subtraction , Animals , Incidence , Thrombosis/epidemiology , VeinsABSTRACT
BACKGROUND AND PURPOSE: Currently, more reliable parameters to predict the risk of aneurysmal rupture are needed. Intra-aneurysmal pressure gradients and flow maps could provide additional information regarding the risk of rupture. Our hypothesis was that phase contrast with vastly undersampled isotropic projection reconstruction (PC-VIPR), a novel 3D MR imaging sequence, could accurately assess intra-aneurysmal pressure gradients in a canine aneurysmal model when compared with invasive measurements. MATERIALS AND METHODS: A total of 13 surgically created aneurysms in 8 canines were included in this study. Pressure measurements were performed in the parent vessel, aneurysm neck, and 5 regions within the aneurysmal sac with a microcatheter. PC-VIPR sequence was used to obtain cardiac-gated velocity measurements in a region covering the entire aneurysm. The velocity and pressure gradient maps derived from the PC-VIPR data were then coregistered with the anatomic DSA images and compared with catheter measurements. RESULTS: In 7 of the bifurcation aneurysms, the velocity flow maps demonstrated a recirculation flow pattern with a small neck-to-dome pressure gradient (mean, +0.5 mm Hg). In 1 bifurcation aneurysm, a flow jet extending from the neck to the dome with significantly greater pressure gradient (+50.2 mm Hg) was observed. All sidewall aneurysms had low flow in the sac with intermediate pressure gradients (mean, +8.3 mm Hg). High statistical correlation existed between PC-VIPR aneurysmal pressures and microcatheter pressure measurements (R = 0.82, P < .01). CONCLUSION: PC-VIPR can provide anatomic as well as noninvasive quantitative and qualitative hemodynamic information in the canine aneurysm model. The PC-VIPR intra-aneurysmal pressure measurements correlated well with catheter measurements.
Subject(s)
Algorithms , Blood Flow Velocity , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Intracranial Aneurysm/diagnosis , Intracranial Aneurysm/physiopathology , Intracranial Pressure , Magnetic Resonance Imaging/methods , Animals , Anisotropy , Dogs , Female , Image Enhancement/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
BACKGROUND AND PURPOSE: Noninvasive assessment of the hemodynamic significance of carotid stenosis is often performed with MR angiography and supplemented with carotid Doppler sonography. Phase contrast with vastly undersampled isotropic projection reconstruction (PC-VIPR), a novel MR imaging technique, accelerates phase-contrast MR flow imaging and provides both images of the vessels and measurements of blood-flow velocities. For this study, we determined the accuracy of PC-VIPR blood-flow velocity measurements to determine pressure gradients across an experimental carotid stenosis. MATERIALS AND METHODS: A focal stenosis was surgically created in each common carotid artery of 6 canines. Digital subtraction angiography (DSA) was performed, and the degree of stenosis was determined using the North American Symptomatic Carotid Endarterectomy Trial methodology. A microcatheter was positioned in the carotid artery proximal and distal to the stenosis, and pressures were measured in the vessel through the catheter. PC-VIPR was then performed on a 1.5T MR imaging scanner with parameters producing 0.8-mm isotropic voxel resolution. From the velocity measurements, pressure gradients were calculated from the Navier-Stokes relationship to compare with the pressures measured by a catheter. RESULTS: Carotid stenoses in the 50%-85% range were produced in the 12 arteries. Pressure gradients across the stenoses ranged from 6 to 26 mm Hg. The pressure gradient calculated from the PC-VIPR data correlated (r = 0.91, P < .0001) with the actual pressure measurements. CONCLUSION: With PC-VIPR, a novel MR imaging technique, the hemodynamic effect of a stenosis on flow and pressure can be evaluated.
Subject(s)
Blood Flow Velocity/physiology , Carotid Stenosis/physiopathology , Disease Models, Animal , Image Enhancement/methods , Image Processing, Computer-Assisted/methods , Magnetic Resonance Angiography/methods , Animals , Blood Pressure/physiology , Carotid Artery, Common/pathology , Carotid Artery, Common/physiopathology , Carotid Stenosis/pathology , Diastole/physiology , Dogs , Female , Systole/physiologyABSTRACT
Four patients underwent angioplasty and stenting of medically refractory symptomatic intracranial atherosclerosis with the new Wingspan stent system. In all 4 patients, CT angiography (CTA) showed an abnormality within the stented segment that was suggestive of nonocclusive in-stent thrombus. However, subsequent conventional angiography findings were typical for in-stent restenosis. The CTA imaging features of in-stent restenosis are important to recognize, and the misinterpretation of in-stent restenosis as in-stent thrombus may result in inappropriate management.
Subject(s)
Blood Vessel Prosthesis/adverse effects , Cerebral Angiography , Graft Occlusion, Vascular/diagnostic imaging , Intracranial Arterial Diseases/diagnostic imaging , Intracranial Arterial Diseases/etiology , Stents/adverse effects , Tomography, X-Ray Computed , Adult , Female , Graft Occlusion, Vascular/etiology , Humans , Male , Treatment OutcomeABSTRACT
BACKGROUND AND PURPOSE: Volume-of-interest C-arm CT is a novel technique for imaging of intracranial high-contrast objects. We performed this study to evaluate the potential diagnostic value and radiation dose reduction of this technique for imaging of intracranial stents and flow diverters. MATERIALS AND METHODS: Twenty-seven patients were imaged with a VOI C-arm CT scan following treatment with a flow diverter or stent-assisted coiling. The radiation dose-area product was recorded for VOI scans. For comparison, the dose-area product from 30 previously acquired consecutive full-view DynaCTs was used. Thermoluminescence dosimetry by using 35 evenly distributed thermoluminescence dosimeters in an anthropomorphic head phantom was also performed by using both conventional full field and VOI acquisitions. Three observers were presented with VOI images for assessment of the potential diagnostic value. RESULTS: The dose-area product measurements showed an exposure reduction of 85% compared with the full field acquisitions used for comparison. The thermoluminescence dosimetry evaluations also showed a considerable dose reduction of 79.8% throughout the volume. For most of the evaluated cases, the observers thought that diagnostically useful information was provided by the VOI images (α = .810). Visualization of device details, such as the extent of opening, positioning, wall apposition, and aneurysm coverage, was judged of good diagnostic quality for most cases (88.9%-92.6%). CONCLUSIONS: In this study, VOI C-arm CT provided high-quality diagnostic images of intracranial stents and flow diverters at a dramatic reduction of radiation exposure. Image content was thought to add useful information. It is a promising method to assess device status during procedures and at follow-up.
Subject(s)
Endovascular Procedures , Neuroimaging/methods , Thermoluminescent Dosimetry/methods , Tomography, X-Ray Computed/methods , Endovascular Procedures/instrumentation , Female , Head , Humans , Phantoms, Imaging , Radiation Dosage , StentsABSTRACT
BACKGROUND AND PURPOSE: HYPRFlow is a novel imaging strategy that provides fast, high-resolution contrast-enhanced time-resolved images and measurement of the velocity of the entire cerebrovascular system. Our hypothesis was that the images obtained with this strategy are of adequate diagnostic image quality to delineate the major components of AVMs. MATERIALS AND METHODS: HYPRFlow and 3D TOF scans were obtained in 21 patients with AVMs with correlative DSA examinations in 14 patients. The examinations were scored for image quality and graded by using the Spetzler-Martin criteria. Mean arterial transit time and overlap integrals were calculated from the dynamic image data. Volume flow rates in normal arteries and AVM feeding arteries were measured from the phase contrast data. RESULTS: HYPRFlow was equivalent to 3D-TOF in delineating normal arterial anatomy, arterial feeders, and nidus size and was concordant with DSA for AVM grading and venous drainage in 13 of the 14 examinations. Mean arterial transit time on the AVM side was 0.49 seconds, and on the normal contralateral side, 2.53 seconds with P < .001. Across all 21 subjects, the mean arterial volume flow rate in the M1 segment ipsilateral to the AVM was 4.07 ± 3.04 mL/s; on the contralateral M1 segment, it was 2.09 ± 0.64 mL/s. The mean volume flow rate in the largest feeding artery to the AVM was 3.86 ± 2.74 mL/s. CONCLUSIONS: HYPRFlow provides an alternative approach to the MRA evaluation of AVMs, with the advantages of increased coverage, 0.75-second temporal resolution, 0.68-mm isotropic spatial resolution, and quantitative measurement of flow in 6 minutes.
Subject(s)
Intracranial Arteriovenous Malformations/diagnosis , Magnetic Resonance Angiography/methods , Magnetic Resonance Imaging/methods , Neuroimaging/methods , Adult , Aged , Angiography, Digital Subtraction/methods , Female , Humans , MaleABSTRACT
The mechanism(s) by which HIV-1 affects neural injury in HIV-1-associated dementia (HAD) remains unknown. To ascertain the role that cellular and viral macrophage products play in HAD neurotoxicity, we explored one potential route for neuronal demise, CXCR4. CXCR4, expressed on lymphocytes and neurons, is both a part of neural development and a co-receptor for HIV-1. Its ligand, stromal cell-derived factor-1alpha (SDF-1alpha), affects neuronal viability. GTP binding protein (G-protein) linked signaling after neuronal exposure to SDF-1alpha, virus-infected monocyte-derived macrophage (MDM) secretory products, and virus was determined. In both human and rat neurons, CXCR4 was expressed at high levels. SDF-1alpha/beta was detected predominantly in astrocytes and at low levels in MDM. SDF-1beta/beta was expressed in HAD brain tissue and upregulated in astrocytes exposed to virus infected and/or immune activated MDM conditioned media (fluids). HIV-1-infected MDM secretions, virus and SDF-1beta induced a G inhibitory (Gi) protein-linked decrease in cyclic AMP (cAMP) and increase inositol 1,4, 5-trisphosphate (IP3) and intracellular calcium. Such effects were partially blocked by antibodies to CXCR4 or removal of virus from MDM fluids. Changes in G-protein-coupled signaling correlated, but were not directly linked, to increased neuronal synaptic transmission, Caspase 3 activation and apoptosis. These data, taken together, suggest that CXCR4-mediated signal transduction may be a potential mechanism for neuronal dysfunction during HAD.
Subject(s)
AIDS Dementia Complex/immunology , Apoptosis/immunology , Neurons/cytology , Receptors, CXCR4/immunology , Signal Transduction/immunology , Animals , Astrocytes/chemistry , Astrocytes/cytology , Astrocytes/virology , Calcium/metabolism , Cell Nucleus/ultrastructure , Cell Nucleus/virology , Cells, Cultured , Chemokine CXCL12 , Chemokines, CXC/genetics , Chemokines, CXC/immunology , Excitatory Postsynaptic Potentials/immunology , Fetus/cytology , Gene Expression/immunology , HIV Envelope Protein gp120/immunology , HIV-1/growth & development , HIV-1/immunology , Hippocampus/cytology , Hippocampus/immunology , Hippocampus/virology , Humans , In Situ Nick-End Labeling , Macrophages/immunology , Macrophages/virology , Microscopy, Electron , Monocytes/immunology , Monocytes/virology , Neurons/chemistry , Neurons/virology , Oligonucleotide Probes , RNA, Messenger/analysis , Rats , Receptors, CXCR4/genetics , Reverse Transcriptase Polymerase Chain Reaction , Synaptic Transmission/immunologyABSTRACT
In a postgraduate training course in general practice in Hamburg two different educational concepts were used and compared with each other. One was oriented more towards problem-based learning, the other more towards lectures. The participants were asked to fill in a written questionnaire after each day (n = 970) and at the end of the course (n = 26). Both courses achieved good results. On a five point scale the median of the general satisfaction was 4. The problem oriented course, however, was judged better than the other in many respects.
Subject(s)
Education, Medical, Continuing , Family Practice/education , Learning , Problem-Based Learning , Teaching/methods , Germany , Humans , Students, Medical , Surveys and QuestionnairesABSTRACT
This paper describes the experiences with different concepts of problem oriented learning in a postgraduate training course in general practice in Hamburg. It is argued that for postgraduate training of general practitioners a four-step-model is more adequate than the "classical" seven-step-model.
Subject(s)
Education, Medical, Graduate , Family Practice/education , Problem-Based Learning , Curriculum , Germany , HumansABSTRACT
BACKGROUND AND PURPOSE: Conventional 3D-DSA volumes are reconstructed from a series of projections containing temporal information. It was our purpose to develop a technique which would generate fully time-resolved 3D-DSA vascular volumes having better spatial and temporal resolution than that which is available with CT or MR angiography. MATERIALS AND METHODS: After a single contrast injection, projections from the mask and fill rotation are subtracted to create a series of vascular projections. With the use of these projections, a conventional conebeam CT reconstruction is generated (conventional 3D-DSA). This is used to constrain the reconstruction of individual 3D temporal volumes, which incorporate temporal information from the acquired projections (4D-DSA). RESULTS: Typically, 30 temporal volumes per second are generated with the use of currently available flat detector systems, a factor of â¼200 increase over that achievable with the use of multiple gantry rotations. Dynamic displays of the reconstructed volumes are viewable from any angle. Good results have been obtained by using both intra-arterial and intravenous injections. CONCLUSIONS: It is feasible to generate time-resolved 3D-DSA vascular volumes with the use of commercially available flat detector angiographic systems and clinically practical injection protocols. The spatial resolution and signal-to-noise ratio of the time frames are largely determined by that of the conventional 3D-DSA constraining image and not by that of the projections used to generate the 3D reconstruction. The spatial resolution and temporal resolution exceed that of CTA and MRA, and the small vessel contrast is increased relative to that of conventional 2D-DSA due to the use of maximum intensity projections.
Subject(s)
Angiography, Digital Subtraction/methods , Four-Dimensional Computed Tomography/methods , Imaging, Three-Dimensional/methods , Intracranial Arteriovenous Malformations/diagnostic imaging , Magnetic Resonance Angiography/methods , Angiography, Digital Subtraction/instrumentation , Animals , Databases, Factual , Feasibility Studies , Four-Dimensional Computed Tomography/instrumentation , Humans , Imaging, Three-Dimensional/instrumentation , Magnetic Resonance Angiography/instrumentation , Phantoms, Imaging , Signal-To-Noise RatioABSTRACT
BACKGROUND AND PURPOSE: Arteriovenous malformations have a high lifetime risk of hemorrhage; however, treatment carries a significant risk of morbidity and mortality, including permanent neurologic sequelae. WSS and other hemodynamic parameters are altered in patients with symptomatic AVMs, and analysis of hemodynamics may have value in stratifying patients into different risk groups. In this study, we examined hemodynamic data from patients with stable symptoms and those who presented with acute symptoms to identify trends which may help in risk stratification. MATERIALS AND METHODS: Phase-contrast MRA using a radial readout (PC-VIPR) is a fast, high-resolution technique that can acquire whole-brain velocity-encoded angiograms with scan times of approximately 5 minutes. Ten patients with AVMs were scanned using PC-VIPR; velocity, area, flow, and WSS in vessels feeding the AVMs and normal contralateral vessels were calculated using velocity data from the phase-contrast acquisition. RESULTS: Patients with an asymptomatic presentation or mild symptoms (n = 4) had no significant difference in WSS in feeding vessels compared with normal contralateral vessels, whereas patients presenting with hemorrhage, severe headaches/seizures, or focal neurologic deficits (n = 6) had significantly higher WSS in feeding vessels compared with contralateral vessels. CONCLUSIONS: In this study, we demonstrate that estimates of WSS and other hemodynamic parameters can be obtained noninvasively in patients with AVMs in clinically useful imaging times. Variation in WSS between feeders and normal vessels appears to relate to the clinical presentation of the patient. Further analysis of hemodynamic changes may improve characterization and staging of AVM patients, when combined with existing risk factors.
Subject(s)
Cerebrovascular Circulation , Imaging, Three-Dimensional , Intracranial Arteriovenous Malformations/diagnosis , Magnetic Resonance Angiography , Adult , Blood Flow Velocity , Cerebral Arteries/pathology , Cerebral Arteries/physiopathology , Female , Humans , Image Processing, Computer-Assisted , Intracranial Arteriovenous Malformations/complications , Intracranial Arteriovenous Malformations/physiopathology , Intracranial Arteriovenous Malformations/therapy , Intracranial Hemorrhages , Magnetic Resonance Angiography/methods , Male , Middle Aged , Shear Strength , Young AdultABSTRACT
BACKGROUND AND PURPOSE: There is no satisfactory parameter that can predict the need for assistant devices for endovascular aneurysm coiling. Our aim was to evaluate the utility of MOA as a predictor of the need for stent-assisted coiling in ICA sidewall aneurysms. MATERIALS AND METHODS: From a retrospective review of an internal data base, 55 consecutive ICA sidewall aneurysms were identified. Thirty-two of the aneurysms were treated by using endovascular techniques. Because 23 of the 55 aneurysms were either untreated or clipped, 3 experienced interventionalists reviewed the 3D images of these aneurysms and then made a decision as to whether stent-assisted coiling would have been required. Thirty-one of the 55 aneurysms would have required stent-assisted coiling, while 24 would not. Neck width, DNR, AR, and MOA were obtained from each aneurysm by using prototype software. These parameters were then correlated with the requirement of stent-assisted coiling. RESULTS: MOA and neck width of aneurysms requiring stent-assisted coiling were significantly larger than those not requiring stent-assisted coiling (P < .001 and <0.001, respectively). Although the DNR and AR of aneurysms requiring stent-assisted coiling were smaller than those not requiring it, the difference was not significant (P = .22 and 0.12, respectively). ROC analysis revealed that MOA was the parameter that best correlated with the need for stent-assisted coiling. Inclusion of MOA with the rest of the parameters significantly increased the predictive performance regarding the need for stent-assisted coiling (P = .005). CONCLUSIONS: In this small study, MOA was a useful parameter to predict the need for stent-assisted coiling in ICA sidewall aneurysms. Further prospective study of this parameter for aneurysms at multiple locations is required to determine its ultimate value.
Subject(s)
Carotid Artery, Internal, Dissection/diagnostic imaging , Carotid Artery, Internal, Dissection/therapy , Embolization, Therapeutic/methods , Intracranial Aneurysm/diagnostic imaging , Intracranial Aneurysm/therapy , Stents , Adult , Aged , Carotid Artery, Internal/diagnostic imaging , Cerebral Angiography , Cohort Studies , Databases, Factual , Humans , Middle Aged , Predictive Value of Tests , Retrospective StudiesABSTRACT
BACKGROUND AND PURPOSE: Color has been shown to facilitate both visual search and recognition tasks. It was our purpose to examine the impact of a color-coding algorithm on the interpretation of 2D-DSA acquisitions by experienced and inexperienced observers. MATERIALS AND METHODS: Twenty-six 2D-DSA acquisitions obtained as part of routine clinical care from subjects with a variety of cerebrovascular disease processes were selected from an internal data base so as to include a variety of disease states (aneurysms, AVMs, fistulas, stenosis, occlusions, dissections, and tumors). Three experienced and 3 less experienced observers were each shown the acquisitions on a prerelease version of a commercially available double-monitor workstation (XWP, Siemens Healthcare). Acquisitions were presented first as a subtracted image series and then as a single composite color-coded image of the entire acquisition. Observers were then asked a series of questions designed to assess the value of the color-coded images for the following purposes: 1) to enhance their ability to make a diagnosis, 2) to have confidence in their diagnosis, 3) to plan a treatment, and 4) to judge the effect of a treatment. The results were analyzed by using 1-sample Wilcoxon tests. RESULTS: Color-coded images enhanced the ease of evaluating treatment success in >40% of cases (P < .0001). They also had a statistically significant impact on treatment planning, making planning easier in >20% of the cases (P = .0069). In >20% of the examples, color-coding made diagnosis and treatment planning easier for all readers (P < .0001). Color-coding also increased the confidence of diagnosis compared with the use of DSA alone (P = .056). The impact of this was greater for the naïve readers than for the expert readers. CONCLUSIONS: At no additional cost in x-ray dose or contrast medium, color-coding of DSA enhanced the conspicuity of findings on DSA images. It was particularly useful in situations in which there was a complex flow pattern and in evaluation of pre- and posttreatment acquisitions. Its full potential remains to be defined.
Subject(s)
Algorithms , Angiography, Digital Subtraction/methods , Colorimetry/methods , Pattern Recognition, Automated/methods , Radiographic Image Enhancement/methods , Radiographic Image Interpretation, Computer-Assisted/methods , Adult , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
BACKGROUND AND PURPOSE: CBV is a key parameter in distinguishing penumbra from ischemic core. The purpose of this study was to compare CBV measurements acquired with standard PCT with ones obtained with C-arm CT in a canine stroke model. MATERIALS AND METHODS: Under an institutionally approved protocol, unilateral MCA strokes were created in 10 canines. Four hours later, DWI was used to confirm the presence of an infarct. CBV maps acquired with PCT were compared with ones acquired by using C-arm CT. Three experienced observers, blinded to the technique used for acquisition, evaluated the CBV maps. RESULTS: An ischemic stroke was achieved in 9 of the 10 animals. Areas of reduced CBV were detected in 70%-75% of the PCT studies and in 83%-87% of the C-arm CT examinations, with false-positives in 1.7% and 3.3%, respectively. False-negatives were found in 25% of the PCT and 12.2% of the C-arm CT studies. In all studies, there was a significant difference between the absolute CBV values in normal and abnormal tissue (P < .005) and no significant difference between PCT and C-arm CT CBV values in either the normal or the abnormal parenchyma (P > .05). CONCLUSIONS: CBV measurements made with C-arm CT compare well with ones made with PCT. While further work is required both to fully validate the technique and to define its ultimate clinical value, it appears that it offers a feasible method for assessing CBV in the angiography suite.
Subject(s)
Blood Volume Determination/methods , Brain Ischemia/diagnostic imaging , Cerebrovascular Circulation , Stroke/diagnostic imaging , Tomography, X-Ray Computed/methods , Acute Disease , Animals , Cerebral Angiography/methods , Cerebral Angiography/standards , Disease Models, Animal , Dogs , False Negative Reactions , False Positive Reactions , Tomography, X-Ray Computed/standardsABSTRACT
BACKGROUND AND PURPOSE: Cerebral blood volume (CBV) is an important parameter in estimating the viability of brain tissue following an ischemic event. We tested the hypothesis that C-arm CT measurements of CBV would correlate well with those made with perfusion CT (PCT). MATERIALS AND METHODS: CBV was measured in 12 canines by using PCT and C-arm CT. Two measurements with each technique were made on each animal; a different injection protocol was used for each of these techniques. PCT was performed by using a 64-section V-scanner. C-arm CT was performed by using a biplane Artis dBA system. PCT images were transferred to a commercially available workstation for postprocessing and analysis; C-arm CT images were transferred to a commercially available workstation for postprocessing and analysis by using prototype software. From each animal, 2 sections from each technique were selected for analysis. RESULTS: There was good agreement of both the color maps and absolute numbers between the 2 techniques. The maximum and mean deviations of values between the 2 techniques for the first 5 animals were 30.20% and 7.82%; for the second 7 animals, these values were 26.79% and 7.40%. The maximum and mean deviations between the 2 C-arm CT studies performed on the first 5 animals were 33.15% and 12.24%; for the second 7 animals, these values were 41.15% and 10.89%. CONCLUSIONS: In these healthy animals, measurement of CBV with C-arm CT compared well with measurements made with PCT.
Subject(s)
Blood Volume Determination/methods , Brain/blood supply , Brain/physiology , Cerebral Angiography/methods , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Animals , DogsABSTRACT
BACKGROUND AND PURPOSE: Recent advances in flat panel detector angiographic equipment have provided the opportunity to obtain physiologic and anatomic information from angiographic examinations. To exploit this possibility, one must understand the factors that affect the bolus geometry of an intra-arterial injection of contrast medium. It was our purpose to examine these factors in a canine model. MATERIALS AND METHODS: Under an institutionally approved protocol conforming to Guide for the Care and Use of Laboratory Animals of the National Institutes of Health, 7 canines were placed under general anesthesia with isoflurane and propofol. Through a 5F catheter placed into the right common carotid artery, a series of biplane angiographic acquisitions was obtained to examine the effects caused by variation in the volume of injection, the rate of injection, the duration of injection, the concentration of contrast medium, and the catheter position on arterial, capillary, and venous opacification. The results of each injection protocol were determined from analysis of a time-contrast concentration curve derived from locations over an artery, in brain parenchyma, and over a vein. The curve was generated from 2D digital subtraction angiography acquisitions by using prototype software. The area under the curve, the amplitude of the curve, and the time to peak (TTP) were analyzed separately for each injection parameter. RESULTS: Changes in the injection protocols resulted in predictable changes in the time-concentration curves. The injection parameter that contributed most to maximum opacification was the volume of contrast medium injected. When the injection rate was fixed and the volume was varied, there was an increase in opacification (maximal) proportional to the injected volume. The injected volume also had an indirect (secondary) impact on the temporal characteristics of the opacification. The time-concentration curve became wider, and the peak was shifted to the right as the injection duration increased. The impact of injected volume on maximal opacification was significant (P < .0001), regardless of the site of measurement (artery, tissue, and vein); however, the impact on the temporal characteristics of the time-concentration curve reached statistical significance only in measurements made in the artery and the vein (P < .05), but not in the tissue (P > .1). The impact of injected volume on maximal opacification became nonproportional in the tissue and vein when the volume was very large (>12 mL). Increasing the concentration of contrast medium resulted in a nonproportional increase in the height of the time-concentration curves (P < .05). Injection rate had an impact on both maximal opacification and TTP. The impact on TTP occurred only when the injection rate was very slow (1 mL/s). Changes of concentration had a similar impact on the time-concentration curve. Catheter position did not cause significant alterations in the shape of the curves. CONCLUSIONS: There were predictable effects from modification of injection parameters on the contrast bolus geometry and on time-concentration curves as measured in an artery, brain parenchyma, or a vein. The amplitude, TTP, and area under the time-concentration curve depend mainly and proportionally on the amount of iodine traversing the vasculature per second. Other injection parameters were of less importance in defining bolus geometry. These findings mimic those observed in studies of parameters affecting bolus geometry following an intravenous injection.
Subject(s)
Angiography, Digital Subtraction/methods , Arteries/metabolism , Capillaries/metabolism , Cerebral Angiography/methods , Contrast Media/administration & dosage , Contrast Media/pharmacokinetics , Veins/metabolism , Animals , Capillaries/diagnostic imaging , Dogs , Injections, Intra-Arterial , Metabolic Clearance Rate , Organization and AdministrationABSTRACT
BACKGROUND AND PURPOSE: Stenosis of the carotid artery may be a cause of reduced cognitive performance that can be ameliorated with placement of a stent. The goal of this study was to measure cognitive performance and speed of psychomotor performance prospectively before and after carotid stent placement. MATERIALS AND METHODS: Patients referred for stent placement for a unilateral carotid artery stenosis were enrolled in the study. Neuropsychologic testing was performed with a Mini-Mental State Examination, an extended mental status examination, a subjective cognitive status measure, and a psychomotor performance test for speed. The severity of the stenosis was measured on angiograms performed before stent placement. Three months after stent placement, CT angiograms were performed and the neuropsychologic testing was repeated. Differences in neuropsychologic test scores before and after stent placement were calculated and tested for significance with a Student t test. RESULTS: Seventeen patients with a single unilateral carotid stenosis of more than 50% completed the study. Stenosis of the carotid artery averaged 80% before treatment and 18% after treatment. After stenting, the scores from the extended mental status examination improved significantly. The scores from the subjective cognitive status measure also improved. No significant change was noted in the scores from the Mini-Mental State Examination or in the speed of psychomotor performance. CONCLUSION: Carotid stent placement in patients with a unilateral stenosis of the carotid artery resulted in significant improvement in cognitive test scores in this highly selected patient group. Further studies are needed to confirm these preliminary observations.