[Perfusion magnetic resonance imaging for high grade astrocytomas: Can cerebral blood volume, peak height, and percentage of signal intensity recovery distinguish between progression and pseudoprogression?]. / Resonancia magnética de perfusión en astrocitomas de alto grado: el volumen sanguíneo cerebral, la altura del pico y el porcentaje de recuperación de intensidad de señal ¿pueden discriminar entre progresión y seudoprogresión?

OBJECTIVES: To study the usefulness of common MRI perfusion parameters for identifying pseudoprogression in high grade astrocytomas. MATERIAL AND METHODS: This retrospective case-control study compared the relative cerebral blood volume (rCBV), the relative percentage of signal intensity recovery (rPSR), and the relative peak height (rPH) recorded in a sample of 17 cases of anaplastic astrocytomas and gliomas considered to be undergoing pseudoprogression by biopsy or follow-up with those recorded in a sample of histologically similar tumors that were treated and considered to be undergoing progression by histologic study or follow-up. We evaluated the accuracy of these parameters and the correlations among them. Statistical significance was set at P<.05. RESULTS: The rCBV, rPSR, and rPH were significantly different between the two groups (P=.001). The cutoff values rPH=1.37, rCBV=0.9, and rPSR=99% yielded sensitivity (S)=88% and specificity (Sp)=82.2% for rPH, S=100% and Sp=100% for rCBV, and S=100% and Sp=70.6% for rPSR, respectively. We found negative correlations between rPRS and rPH (-0.76) and between rPRS and rCBV (-0.81) and a high positive correlation between rPH and rCBV (0.87). CONCLUSION: The variables rPH and rCBV were useful for differentiating between pseudoprogression and true progression in our sample. The variable rPRS was also very sensitive, although the overlap in the values between samples make it less useful a priori.

[Thrombolysis in stroke: inappropriate consideration of the 'window period' as the time available]. / Trombólisis en el ictus: consideración inapropiada del 'período de ventana' como tiempo disponible.

AIMS: The earlier r-TPA is administered in ischaemic strokes, the more effective it is. The aim of this study is to analyse the delay times in health care afforded in a consecutive series of cases that had received treatment, with a view to shortening them. PATIENTS AND METHODS: We analysed the medical records of the first patients to be treated in our centre. The paper describes several variables involving demographic and clinical factors, as well as the delay in entering the Emergency department, performing a CAT scan and especially the time elapsed between the CAT scan and starting treatment. We have examined the existence of an inappropriate correlation between delays that should be independent of one another. RESULTS: The mean age of the 17 patients treated was 68 years and they had a stroke severity score of 17 points on the NIHSS. The mean time of delay until arrival, arrival-CAT, and CAT-treatment were slightly under 1 hour each, and onset-treatment delay was 165 minutes, which is very close to the limit of the therapeutic window period. We found a strong inverse linear association between the time elapsed between onset and the CAT scan, and from the latter to the beginning of treatment (Spearman's r: -0.664, p = 0.004). CONCLUSIONS: Findings indicate that in our hospital, as in other centres in the initial phases of implementation, the therapeutic time window for intravenous thrombolysis in ischaemic stroke tends to run out. It must be highlighted that the resolve of the physician who indicates the treatment exerts a decisive effect on the delay.