Early ischaemic diffusion lesion reduction in patients treated with intravenous tissue plasminogen activator: infrequent, but significantly associated with recanalization.

BACKGROUND AND PURPOSE

Recent studies have shown that thrombolysis could decrease or eliminate ischaemic diffusion-weighted imaging lesions. However, the features of such diffusion-weighted imaging lesion reduction are not well known.

AIMS

To clarify, the frequency of and factors associated with lesion reduction were investigated.

METHODS

Patients given intravenous tissue plasminogen activator therapy within three-hours of onset were prospectively enrolled. Magnetic resonance imaging including diffusion-weighted imaging and magnetic resonance angiography was performed four times: on admission, just after intravenous tissue plasminogen activator, 24 h from intravenous tissue plasminogen activator, and seven-days after intravenous tissue plasminogen activator. The diffusion-weighted imaging lesion volume was measured by manual trace using National Institutes of Health imaging software. All patients were divided into three groups according to the early diffusion-weighted imaging lesion volume change from admission to just after intravenous tissue plasminogen activator: the lesion reduction group (>20% decrease); the lesion growth group (>20% increase); and the lesion unchanged group.

RESULTS

In total, 105 patients [56 males, median age 77 (interquartile range 70-83) years, and National Institutes of Health Stroke Scale score 16 (10-22)] were enrolled. Early diffusion-weighted imaging lesion reduction was observed in seven (7%) patients. The decreased lesion increased subsequently. On multivariate analysis, the glucose level on admission (odds ratio 0·95, 95% confidence interval 0·91 to 0·99, P = 0·045) and early recanalization (odds ratio 15·7, 95% confidence interval 1·61 to 153, P = 0·018) were independently related to early lesion reduction.

CONCLUSION

Early diffusion-weighted imaging lesion reduction was observed in 7% of patients treated with intravenous tissue plasminogen activator. The decreased lesion increased subsequently. Initial glucose level and early recanalization were independently associated with early diffusion-weighted imaging lesion reduction.