Beating the clock: time delays to thrombolytic therapy with advanced imaging and impact of optimized workflow.

BACKGROUND: The effectiveness of intravenous tissue plasminogen activator in the management of acute ischemic strokes diminishes significantly with time. Advanced computed tomography (CT) imaging can be helpful to identify candidates for neurointerventional procedures. We have successfully used a 320-slice Toshiba volume CT scanner since mid-2008. Other centers have forgone advanced imaging because of concerns of time delay. This study is to assess the time delay while using this scanner compared with our 64-slice scanner. METHODS: Treatment times of patients scanned with advanced imaging (CT head, dynamic CT angiography, and whole brain perfusion-group A) and patients scanned in a 64-slice scanner (CT head and traditional CT angiogram-group B) were compared. Two groups of stroke patients from November-March 2009-2010 (group 1) and 2012-2013 (group 2) were audited to assess temporal improvement. Multiple timing variables were analyzed. RESULTS: One hundred fifty-three cases from 2009/10 and 192 cases from 2012/13 were analyzed. The median door-to-needle time (DNT) for group 1A and group 2A was 57 minutes and 47 minutes, respectively. The median DNT for group 1B and group 2B was 54 minutes and 49 minutes, respectively. Decrease in the overall DNT with group A can be attributed to the "streamlining" of the stroke code process. There was no difference in the DNT for patients who presented during working hours versus those who presented during nonworking hours. CONCLUSIONS: With adequate experience and training, advanced stroke imaging with whole brain perfusion/dynamic CT angiography can be performed with treatment times that are comparable with traditional CT scanning.

Dynamic characterization of the CT angiographic 'spot sign'.

BACKGROUND AND PURPOSE: Standard (static) CT angiography is used to identify the intracerebral hemorrhage (ICH) spot sign. We used dynamic CT-angiography to describe spot sign characteristics and measurement parameters over 60-seconds of image acquisition. METHODS: We prospectively identified consecutive patients presenting with acute ICH within 4.5 hours of symptom onset, and collected whole brain dynamic CT-angiography (dCTA). Spot parameters (earliest appearance, duration, maximum Hounsfield unit (HU), time to maximum HU, time to spot diagnostic definition, spot volume and hematoma volumes) were measured using volumetric analysis software. RESULT: We enrolled 34 patients: three were excluded due to secondary causes of ICH. Of the remaining 31 patients there were 18 females (58%) with median age 70 (range 47-86) and baseline hematoma volume 33 ml (range 0.7-103 ml). Positive dCTA spot sign was present in 13 patients (42%) visualized as an expanding 3-dimensional structure temporally evolving its morphology over the scan period. Median time to spot appearance was 21 s (range 15-35 seconds). This method allowed tracking of spots evolution until the end of venous phase (active extravasation) with median duration of 39 s (range 25-45 seconds). The average density and time to maximum density was 204HU and 30.8 s (range 23-31 s) respectively. Median time to spot diagnosis was 20.8 s using either 100 or 120HU definitions. CONCLUSION: Dynamic CTA allows a 3-dimensional assessment of spot sign formation during acute ICH, and captured higher spot sign prevalence than previously reported. This is the first study to describe and quantify spot sign characteristics using dCTA; these can be used in ongoing and upcoming ICH studies.