The patient, a 65-year-old male, presented with sudden onset of left-arm weakness and aphasia. A CT angiogram of the carotids demonstrated right internal carotid stenosis.

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The exam was performed on a LightSpeed® VCT XT using the GE-exclusive VolumeShuttle™ scanning mode.

Acquisition protocol

• Scanner: LightSpeed VCT XT
• Scan type: CT Perfusion using VolumeShuttle
• CT Perfusion VolumeShuttle protocol Axial
• Rotation speed: 0.4 second
• Detector configuration: 64 x 0.625 mm – 8i 5 mm x 2 = 16 5-mm slices
• kVp: 80
• mA: 500
• Total X-ray exposure time: 13.6 seconds
• Total scan time: 46.6 seconds
• Coverage: 80 mm
• Travel distance: 40 mm in 2.8 seconds
• Recon kernel: Standard
• SFOV: 32

Clinical findings

Diamox challenge to assess vascular reserve. Pre/post perfusion exams were done. Non-contrast brain shows small ischemic area in superior parietal area (Figures 1a-d).

Pre-Diamox perfusion scan shows increase in mean transit time in right temporal and parietal area. (Figure 2a-e Series view, BV, BF, MTT, Scout with scan range of 80 mm Figures 2f-I Series view, BV, BF, MTT).

Post Diamox – 10-minute delay – shows increased area of MTT in the parietal area (Figures 3a-e Series view, graph, BV, BF, MTT, Figures 3f-I). Post acquisition is 19 passes for 50.2 seconds.

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Interventions

Based on results and coverage provided by the VolumeShuttle scanning mode on the LightSpeed VCT XT, medical management was prescribed for this patient versus interventional treatment. Neurologist confidence was increased by the additional volume of brain examined.

Advantages of using the GE LightSpeed VCT XT and VolumeShuttle in this exam

• VolumeShuttle provides 80 mm of coverage on the LightSpeed VCT XT, compared to 40 mm of coverage for non-shuttle exams on the LightSpeed VCT and 20 mm of coverage on non-VCT systems.
• This increased coverage provides diagnostic confidence.