***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND AND PURPOSE : Independent evaluation of angiographic images is becoming widely applied in the assessment of treatment outcomes of cerebral aneurysms . In the current study , we assessed the agreement between an independent core laboratory and the operators regarding angiographic appearance in a recent r and omized , controlled trial . MATERIAL S AND METHODS : Data were derived from the Cerecyte Coil Trial . Angiographic images of each coiled aneurysm , taken immediately after embolization and at 5- to 7-month follow-up , were evaluated by the operator at the treating center and by an independent neuroradiologist at the core laboratory . For the purpose of this study , images were interpreted on a 3-point scale to provide uniformity for analysis ; grade 1 : complete occlusion , grade 2 : neck remnant ; and grade 3 : sac filling . “ Unfavorable angiographic appearance ” was defined as grade 3 at follow-up or interval worsening of grade between the 2 time points . RESULTS : The study included 434 aneurysms . Immediately after embolization , grade 3 was reported by operators in 39 ( 9 % ) compared with 52 ( 12 % ) by the core laboratory ( P = .159 ) . On follow-up , grade 3 was reported by operators in 44 ( 10 % ) compared with 81 ( 19 % ) by the core laboratory ( P < .0001 ) . Overall , operators noted unfavorable angiographic appearance in 78 ( 18 % ) compared with 134 ( 31 % ) by the core laboratory ( P < .0001 ) . At every time point , agreement between the core laboratory and the operators was slight . CONCLUSIONS : Unfavorable angiographic appearance was noted almost twice as frequently by an independent core laboratory as compared with the operators . Planning of trials and interpretation of published studies should be done with careful attention to the mode of angiographic appearance interpretation Introduction Since digital subtraction angiography ( DSA ) carries a low risk of morbidity , and is associated with patient discomfort and higher cost , our objective was to determine whether high-resolution 3-D time-of-flight MR angiography ( TOF-MRA ) at 3 T may replace DSA in the follow-up of patients after coiling of an intracranial aneurysm . Methods This prospect i ve study included 50 consecutive patients with a ruptured and subsequently coiled intracranial aneurysm . All patients were followed up at a mean of 14 months after coiling with DSA and high-resolution 3-D TOF-MRA at 3 T generating 0.02 mm3 isotropic voxels . One examiner used DSA and TOF-MR angiograms to assess the need for and risk of retreatment ; these data were used to calculate intermodality agreement . Another two examiners independently assessed aneurysm occlusion by DSA and TOF-MRA according to the Raymond scale ; these data were used to calculate interobserver agreement . Results Discrepancies between DSA and TOF-MRA were found in three patients ( intermodality agreement κ = 0.86 ) . While DSA indicated complete aneurysm occlusion , TOF-MRA showed small neck remnants in the three patients . Coils on all DSA projections obscured these three neck remnants . Interobserver agreement was higher for DSA ( κ = 0.82 ) than for TOF-MRA ( κ = 0.68 ) , which was in part due to the complexity of the information provided by TOF source images and reconstructions . Conclusion 3-D TOF-MRA at 3 T is not only an adjunctive tool but is ready to replace DSA in the follow-up of patients with previously coiled intracranial aneurysms . Additional DSA may only be performed in complex and not clearly laid out aneurysms BACKGROUND AND PURPOSE Digital subtraction angiography ( DSA ) is used to follow-up intracranial aneurysms treated with detachable coils to identify recurrence and determine need for additional treatment . However , DSA is invasive and involves a small risk of neurologic complications . We assessed the feasibility and usefulness of 3D time-of-flight ( TOF ) MR angiography ( MRA ) performed at 3 T compared with DSA for the follow-up of coil-treated intracranial aneurysms . METHODS In a prospect i ve study , 20 consecutive patients with 21 intracranial aneurysms treated with coils underwent DSA and nonenhanced and enhanced multiple overlapping thin-slab acquisition 3D TOF MRA at 3 T on the same day at a mean follow-up of 6 months ( range , 4 - 14 months ) after coil placement . MRA images were evaluated for presence of artifacts , presence and size of aneurysm remnants and recurrences , patency of parent and branch vessels , and added value of contrast material enhancement . MRA and DSA findings were compared . RESULTS Interobserver agreement of MRA was good , as was agreement between MRA and DSA . All three recurrences that needed additional treatment were detected with MRA . Minor disagreement occurred in four cases : three coil-treated aneurysms were scored on MRA images as having a small remnant , whereas on DSA images these aneurysms were occluded ; the other aneurysm was scored on MRA images as having a small remnant , whereas on DSA images this was a small recurrence . Use of contrast material had no additional value . Coil-related MR imaging artifacts were minimal and did not interfere with evaluation of the occlusion status of the aneurysm . CONCLUSION High-spatial-resolution 3D TOF MRA at 3 T is feasible and useful in the follow-up of patients with intracranial aneurysms treated with coil placement Background and Purpose — The purpose of this study was to estimate the performance measures of MR angiography ( MRA ) in the diagnosis of aneurysm residual flow after coil occlusion . Methods — Patients having at least 1 cerebral aneurysm treated with coil occlusion were prospect ively and consecutively enrolled . Time of flight and contrast-enhanced MRA were performed the same day of the DSA follow-up . The degree of aneurysm occlusion and dimensions of the residual flow were evaluated by independent readers at MRA and digital subtraction angiogram . MRA performance measures were estimated in a cross-sectional analysis and repeated in subgroups of aneurysm sizes and locations . MRA predictive values for recurrence were also estimated using a longitudinal design . Results — We obtained 167 aneurysm evaluations for each imaging modality . Class 3 residual flow was seen on digital subtraction angiogram follow-up in 27 % . The sensitivity and specificity of MRA was 88 % ( 95 % CI , 80–94 ) and 79 % ( 95 % CI , 67–88 ) , respectively . The positive predictive value for a Class 3 recurrence was 67 % ( 95 % CI , 51–80 ) and the negative predictive value was 93 % ( 95 % CI , 86–97 ) . Time-of-flight MRA underestimated the length of the residual flow ( P=0.039 ) , whereas contrast-enhanced MRA overestimated its width ( P<0.0001 ) . MRA sensitivity for a Class 3 residual flow was lower for aneurysms < 6 mm ( P=0.01 ) . Conclusions — MRA has sufficient accuracy for screening of aneurysm residual flow after coil occlusion . Due to its lower negative predictive value , recurrent aneurysms should be confirmed with digital subtraction angiogram before planning a retreatment . Routine use of MRA to follow small aneurysms should wait better estimation of its performance in this particular subgroup BACKGROUND AND PURPOSE : Blood-pool agents are promising in the imaging of small vessels with slow or complex flow . Our aim was to compare blood-pool contrast-enhanced MR angiography ( BPCE-MRA ) using gadofosveset trisodium ( Vasovist ) with 3D time-of-flight MRA ( TOF-MRA ) in the follow-up of intracranial aneurysms after endovascular therapy . MATERIAL S AND METHODS : We included 32 patients with a total of 37 coiled aneurysms . MRAs in the early steady-state phase were performed on a 1.5 T scanner within 8 days of digital subtraction angiography ( DSA ) . Two radiologists independently analyzed TOF-MRA and BPCE-MRA images . Consensus was reached by review involving a third neuroradiologist . DSA images were interpreted separately by an interventional radiologist . Findings were assigned to 1 of 3 categories : 1 ) complete occlusion , 2 ) residual neck , and 3 ) residual aneurysm . RESULTS : Follow-up DSA demonstrated 13 complete obliterations ( class 1 ) , 13 residual necks ( class 2 ) , and 11 residual aneurysms ( class 3 ) . Weighted κ statistics showed substantial concordance of TOF-MRA and DSA ( 0.664 ) as well as BPCE-MRA and DSA ( 0.724 ) ratings . Comparison between TOF-MRA and BPCE-MRA found excellent agreement ( 0.818 ) with only 6 ( 16.2 % ) discrepancies . For detecting residual flow , the difference in accuracy of both MRA techniques ( 83.8 % versus 91.9 % ) was not significant ( McNemar , P = 1.000 ) . BPCE-MRA showed a tendency towards higher sensitivity and specificity ( 91.7 % and 92.3 % , respectively ) compared with TOF-MRA ( 87.5 % and 76.9 % ) . CONCLUSIONS : In classifying the completeness of endovascular cerebral aneurysm therapy , we found that BPCE-MRA and 3D TOF-MRA showed very good agreement . The use of Vasovist did not lead to a significantly increased accuracy of MRA follow-up BACKGROUND AND PURPOSE : MR angiography ( MRA ) is increasingly used as a noninvasive imaging technique for the follow-up of coiled intracranial aneurysms . However , the need for contrast enhancement has not yet been eluci date d. We compared 3D time-of-flight MRA ( TOF-MRA ) and contrast-enhanced MRA ( CE-MRA ) at 3 T with catheter angiography . MATERIAL S AND METHODS : Sixty-seven patients with 72 aneurysms underwent TOF-MRA , CE-MRA , and catheter-angiography 6 months after coiling .  Occlusion status on MRA was classified as adequate ( complete and neck remnant ) or incomplete by 2 independent observers . For TOF-MRA and CE-MRA , interobserver agreement , intermodality agreement , and correlation with angiography were assessed by κ statistics . RESULTS : Catheter-angiography revealed incomplete occlusion in 12 ( 17 % ) of the 69 aneurysms ; 3 aneurysms were excluded due to MR imaging artifacts . Interobserver agreement was good for CE-MRA ( κ = 0.77 ; 95 % confidence interval [ CI ] , 0.55–0.98 ) and very good for TOF-MRA ( κ = 0.89 ; 95 % CI , 0.75–1.00 ) . Correlation of TOF-MRA and CE-MRA with angiography was good . The sensitivity of TOF-MRA and CE-MRA was 75 % ( 95 % CI , 43%–95 % ) ; the specificity of TOF-MRA was 98 % ( 95 % CI , 91%–100 % ) and of CE-MRA , 97 % ( 95 % CI , 88%–100 % ) . All 5 incompletely occluded aneurysms , which were additionally treated , were correctly identified with both MRA techniques . Areas under the receiver operating characteristic curve for TOF-MRA and CE-MRA were 0.90 ( 95 % CI , 0.79–1.00 ) and 0.91 ( 95 % CI , 0.79–1.00 ) . Intermodality agreement between TOF-MRA and CE-MRA was very good ( κ = 0.83 ; 95 % CI , 0.65–1.00 ) , with full agreement in 66 ( 96 % ) of the 69 aneurysms . CONCLUSIONS : In this study , TOF-MRA and CE-MRA at 3 T were equivalent in evaluating the occlusion status of intracranial aneurysms after coiling . Because TOF-MRA does not involve contrast administration , this method is preferred over CE-MRA Introduction To prospect ively compare of the diagnostic value of digital subtraction angiography ( DSA ) and time-of-flight magnetic resonance angiography ( TOF-MRA ) in the follow-up of intracranial aneurysms after endovascular treatment . Methods Seventy-two consecutive patients were examined 3 months after the embolization . The index tests included : two-dimensional DSA ( 2D-DSA ) , three-dimensional DSA ( 3D-DSA ) , and TOF-MRA . The reference test was a retrospective consensus between 2D-DSA images , 3D-DSA images , and source rotational DSA images . The evaluation included : detection of the residual flow , quantification of the flow , and validity of the decision regarding retreatment . Intraobserver agreement and interobserver agreement were determined . Results The sensitivity and specificity of residual flow detection ranged from 84.6 % ( 2D-DSA and TOF-MRA ) to 92.3 % ( 3D-DSA ) and from 91. 
    Output:
    
Reliability varied significantly as a function of imaging methods , grading scales , occlusion rates , and their interaction .
Observer agreement substantially increased with increasing occlusion rate in digital subtraction angiography but not in MR angiography .
Reliability was higher in studies using 2- or 3-value grading scales than in studies with 4-value grading scales .
On the basis of our analysis , we found that the combination of magnetic resonance angiography , 3-value grading scale , and 2 trained raters seems most promising for usage as surrogate study end points