Yes, you must obtain a CT scan before administering rTPA
A non-contrast CT head is absolutely essential and must be performed before giving rTPA to exclude intracranial hemorrhage, which is an absolute contraindication to thrombolytic therapy. 1, 2
Why CT is Mandatory Before rTPA
The American Heart Association and American College of Radiology both provide Class I, Level A recommendations that either non-contrast CT (NECT) or MRI must be obtained before administering intravenous tPA to exclude intracranial hemorrhage (ICH). 1 This is non-negotiable because:
Hemorrhage exclusion is absolute: ICH is an absolute contraindication to thrombolytic therapy, and administering tPA in the presence of hemorrhage would be catastrophic. 1, 2
Early ischemic changes guide treatment: The CT also identifies early ischemic changes that help estimate irreversible tissue damage using scoring systems like ASPECTS, which is essential for therapeutic decision-making. 1
Stroke mimics must be excluded: Non-contrast CT rules out other etiologies (tumors, subdural hematomas, etc.) that may present with stroke-like symptoms but require completely different management. 1, 2
The Critical Caveat: Don't Let Imaging Delay Treatment
While imaging is mandatory, the acquisition of CT cannot unduly delay tPA administration within the 3-hour window. 1 This means:
Keep it simple initially: Within the first 3 hours, obtain non-contrast CT head rapidly. Additional studies like CTA or perfusion imaging are justifiable but cannot delay tPA bolus. 1
Time targets matter: In clinical practice, the average time from CT completion to tPA administration should be under 60 minutes, with door-to-needle times ideally under 60 minutes total. 3
Advanced imaging is optional early: MRI with diffusion-weighted imaging (DWI) is superior to CT for detecting acute ischemia, but only use it if it doesn't delay tPA administration. 1
What About Additional Vascular Imaging?
For patients within 3 hours presenting with suspected large vessel occlusion (LVO), you should obtain CTA head immediately after non-contrast CT if it doesn't delay tPA. 1 Here's the algorithm:
Start with non-contrast CT in all suspected stroke patients to exclude hemorrhage. 1, 2
Add CTA head immediately if clinical presentation suggests LVO (high NIHSS, cortical signs) because this identifies candidates for endovascular thrombectomy. 1
CTA neck can be added simultaneously to assess extracranial vasculature and aid surgical planning for thrombectomy. 1
CT perfusion is usually unnecessary within the first 6 hours and may actually be harmful by creating delays in clear thrombectomy candidates. 1
Special Considerations for Extended Time Windows
For patients presenting 6-24 hours after symptom onset with confirmed LVO on CTA, CT perfusion or MR perfusion may be required to determine thrombectomy eligibility. 1 This reflects the paradigm shift from time-based to tissue-based selection in extended windows. 1
Common Pitfalls to Avoid
Never give tPA without imaging first: Even if the clinical presentation is classic for stroke, hemorrhage must be excluded. 1
Don't order contrast-enhanced CT alone: There is no role for CT head with IV contrast in acute stroke evaluation—it provides no benefit and may obscure hemorrhage. 1, 2
Don't let perfusion imaging delay treatment: In the early window (<6 hours) with clear LVO, perfusion studies create harmful delays. 1
Frank hypodensity >1/3 MCA territory is a strong contraindication: While early ischemic changes don't preclude treatment, large completed infarcts on CT are a contraindication. 1
**Microbleeds on gradient-echo MRI (<5) are not contraindications**: If you happen to get MRI first, small numbers of microbleeds don't preclude tPA, though the risk with >5 microbleeds is uncertain. 1