Comparison of Tmax values between full- and half-dose gadolinium perfusion studies

Area of Science:

• Neuroradiology
• Medical Imaging
• Stroke Management

Background:

• AHA guidelines recommend perfusion imaging for acute ischemic stroke patient selection within the 6-24 hour window.
• Concerns regarding gadolinium-based contrast agent (GBCA) brain accumulation prompt recommendations to limit their use.
• The Time to Maximum (Tmax) parameter is crucial for stroke assessment in trials like DAWN and DEFUSE 3.

Purpose of the Study:

• To investigate if a reduced gadolinium dose in MR perfusion imaging yields similar Tmax delay patterns compared to standard doses.
• To evaluate the safety and efficacy of half-dose GBCA for Tmax parameter assessment in acute ischemic stroke.

Main Methods:

• Prospective study of 10 acute ischemic stroke patients undergoing two MR perfusion scans.
• Scans included a standard-dose and a subsequent half-dose gadolinium injection (median 7 min apart).
• Comparison of Tmax maps derived from both standard and half-dose perfusion imaging.

Main Results:

• The mean difference in Tmax between half- and full-dose scans was minimal (0.1 s).
• 93.7% of brain tissue showed Tmax differences of no more than ±1 second between the two doses.
• Half-dose gadolinium provided comparable Tmax measurements to full-dose scans in patients with normal or modest Tmax delays.

Conclusions:

• Half-dose gadolinium contrast agents are effective for Tmax measurement in MR perfusion imaging for acute ischemic stroke.
• This approach may allow for reduced GBCA administration while preserving diagnostic information for stroke patient selection.
• Further research can validate these findings and explore broader clinical applications of reduced-dose gadolinium perfusion imaging.