Use of T₁ relaxation time in rotating frame (T₁ ρ) and apparent diffusion coefficient to estimate cerebral stroke...

The major factor for the appropriate treatment strategies for ischemia patients is its onset timing.

To study to evaluate the diagnostic accuracy of T₁ relaxation time in a rotating frame (T₁ ρ) and apparent diffusion coefficient (ADC) from MRI to estimate ischemia stages.

Prospective.

In all, 73 patients (49 males, aged 29-78 years and 24 females, aged 22-94 years) with ischemia were prospectively imaged with T₁ ρ and diffusion MRI during the postischemic period.

3T/T₁ ρ and diffusion-weighted imaging (DWI).

Ischemic parenchyma included tissue with elevated signal areas on DWI and correlative hypointense areas on ADC maps.

The sensitivity of variables to ischemia time was quantified by analyzing the respective correlations of these values with onset time.

ΔT₁ ρ (ipsilateral-contralateral differences in T₁ ρ) (R²  = 0.956) and T₁ ρ_ipsi (ipsilateral ischemia T₁ ρ values) (R²  = 0.941) were elevated in all ischemic lesions; these values increased linearly as a function of time, unlike ΔADC (ipsilateral-contralateral differences in ADC) (R²  = -0.410) and ADC_ipsi (ipsilateral ischemia ADC values) (R²  = 0.550). ΔT₁ ρ and T₁ ρ_ipsi were significantly different between all stages (P < 0.01), except the acute and hyperacute stages (P = 0.589 for ΔT₁ ρ, P = 0.290 for T₁ ρ_ipsi , respectively), but ΔADC and ADC_ipsi only between the late subacute and early subacute stages (P < 0.01) and the late subacute and chronic stages (P < 0.01).

These data suggest that T₁ ρ can provide estimates for the ischemic time in patients. T₁ ρ has the potential to outperform diffusion for single-timepoint examination because the T₁ ρ change during strokes is positive and linear. If patients with suspected stroke are scanned by MRI within the appropriate timeframe, T₁ ρ may provide tools for evaluating stroke onset, potentially aiding in treatment strategies.

4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1247-1254.