cliot (version 1.0.0)

modified_fisher_grade: Modified Fisher Grading Scale for Subarachnoid Hemorrhage

Description

Calculates the Modified Fisher Grade, an updated radiographic scale for predicting the risk of delayed cerebral ischemia (vasospasm) following subarachnoid hemorrhage. Unlike the original Fisher scale, this version specifically accounts for the presence of intraventricular hemorrhage (IVH) and thick cisternal blood separately.

Usage

modified_fisher_grade(sah_present, ich_ivh_present, clot_thickness_ge_1mm)

Value

A list containing:

Modified_Fisher_Grade

The calculated grade (0-4).

CT_Findings

Description of the radiographic pattern.

Symptomatic_Vasospasm_Risk

Estimated risk percentage.

Arguments

sah_present

Numeric (0 or 1). Is subarachnoid hemorrhage present? (1 = Yes).

ich_ivh_present

Numeric (0 or 1). Is intraventricular hemorrhage (IVH) present? (1 = Yes).

clot_thickness_ge_1mm

Numeric (0 or 1). Is the SAH clot thick (>= 1 mm)? (1 = Yes).

References

Claassen J, Bernardini GL, Kreiter K, et al. Effect of cisternal and ventricular blood on risk of delayed cerebral ischemia after subarachnoid hemorrhage: the Fisher scale revisited. Stroke. 2001;32(9):2012-2020. doi:10.1161/hs0901.095677

Examples

# Example 1: Highest Risk (Grade 4)
# Thick SAH (1), IVH (1)
modified_fisher_grade(1, 1, 1)

# Example 2: Intermediate Risk (Grade 2)
# Thin SAH (0), IVH (1)
modified_fisher_grade(1, 1, 0)