Pneumothorax following ultrasound-guided jugular vein puncture for central venous access in interventional radiology: 4 years of experience.

PURPOSE: The purpose of our study was to review the rate of pneumothorax following central venous access, using real-time ultrasound guidance. MATERIALS AND METHODS: Data related to ultrasound-guided venous puncture, for central venous access, performed between July 1, 2004 and June 30, 2008 was retrospectively and prospectively collected. Access route, needle gauge, catheter type, and diagnosis of pneumothorax on the intraprocedure spot radiographs and or the postprocedure chest radiographs, were recorded. RESULTS: A total of 1262 ultrasound-guided jugular venous puncture for central venous access were performed on a total of 1066 patients between July 1, 2004 and June 30, 2008. Access vessels included 983 right internal jugular veins, 275 left internal jugular veins, and 4 right external jugular veins. No pneumothorax (0%) was identified. CONCLUSION: Due to an extremely low rate of pneumothorax following ultrasound-guided central venous access, 0% in our study and other published studies, we suggest that routine postprocedure chest radiograph to exclude pneumothorax may be dispensed unless it is suspected by the operator or if the patient becomes symptomatic.

Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke research.

BACKGROUND AND PURPOSE: The measurement of ischemic lesion volume on diffusion- (DWI) and perfusion-weighted MRI (PWI) is examiner dependent. We sought to quantify the variance imposed by measurement error in DWI and PWI lesion volume measurements in ischemic stroke. METHODS: Fifty-eight consecutive patients with DWI and PWI within 12 hours of symptom onset and follow-up MRI on >or= day-5 were studied. Two radiologists blinded to each other measured lesion volumes by manual outlining on each image. Interexaminer reliability was evaluated by intraclass correlation coefficients (ICC) and relative paired difference or RPD (ratio of difference between 2 measurements to their mean). The ratio of between-examiner variability to between-subject variability (variance ratio) was calculated for each imaging parameter. RESULTS: The correlation (ICC) between examiners ranged from 0.93 to 0.99. The median RPD was 10.0% for DWI, 14.1% for mean transit time, 18.9% for cerebral blood flow, 21.0% for cerebral blood volume, 16.8% for DWI/MTT mismatch, and 6.3% for chronic T2-weighted images. There was negative correlation between RPD and lesion volume in all but chronic T2-weighted images. The variance ratio ranged between 0.02 and 0.10. CONCLUSIONS: Despite high correlation between volume measurements of abnormal regions on DWI and PWI by different examiners, substantial differences in individual measurements can still occur. The magnitude of variance from measurement error is primarily determined by the type of imaging and lesion volume. Minimizing this source of variance will better enable imaging to deliver on its promise of smaller sample size.