Score — Marfan Z

[ Z = \frac\textObserved aortic root diameter - \textPredicted mean diameter\textStandard deviation (SD) of predicted mean ]

Predicted mean = ( 14.0 + 18.7 \times 2.04 = 14.0 + 38.15 = 52.15 \text mm ) SD = ( 1.89 + 1.08 \times 2.04 = 1.89 + 2.20 = 4.09 \text mm ) marfan z score

[ Z = \frac46 - 52.154.09 = \frac-6.154.09 = -1.50 \ (\textstill normal) ] [ Z = \frac\textObserved aortic root diameter -