A stroke neurologist/nurse operated acute stroke TCD service can reliably identify MCA occlusion when compared to MRA.
Background: Hyperacute neurovascular imaging has great potential to help clinicians better tailor stroke therapy. Future decisions to use intravenous and/or intra-arterial lytics may depend on site of MCA occlusion. TCD has not been seriously considered as such a technique because of the misconception TCD is too operator dependent and not reliable. We evaluated if our acute stroke TCD service could accurately and reliably identify MCA occlusion. Methods: A series of acute stroke patients underwent TCD examination by 1 of 3 stroke physicians or 1 stroke nurse. MRA was also performed at a time closely corresponding to TCD exam. Blind to MRA findings and patient info except symptom side, all 4 sonographers independently interpreted the TCD exam for presence of MCA occlusion using previously established TCD criteria and evaluated TIBI flow grades (5 normal waveform, 4 stenotic, 3 dampened, 2 blunted, 1 minimal, 0 absent) at 65, 55, 45 mm MCA depths. This result was compared to blinded neuroradiologists MRA interpretation for M1-MCA and distal MCA occlusion. Results: 37 cases compared. Mean age 67, median baseline NIHSS 8. Median symptom onset to TCD 5.9 hours and MRA 6.3 hours. Median time between TCD and MRA 1.3 hours. TPA treatment preceded or occurred during TCD or MRA imaging in 27% of cases. MRA identified 19 MCA occlusion (12 M1-MCA, 7 distal MCA) and 18 no MCA occlusion. Comparing all sonographer TCD interpretations (n=148) with MRA the sensitivity, specificity, PPV, NPV for MCA occlusion was: 82%, 81%, 82%, 81% respectively. Intraclass correlation coefficent for TIBI flow grades at prox, mid, distal MCA depths was : 0.73,0.84,0.83. Median TIBI scores at these 3 MCA depths respectively were: 5,5,5 when no MCA occlusion on MRA, 3,3,3 if distal MCA occlusion and 2,2,2 if M1-MCA occlusion. Conclusion: TCD showed good accuracy at identifying MCA occlusion compared to MRA when TCD was performed and interpreted by a stroke clinician/nurse. TIBI flow grades were reliably identified and appear potentially useful to discriminate between normal MCA, and proximal or distal MCA occlusion. TCD is a useful bedside tool that could aid future stroke treatment.