Table 1.

Summary of patient demographics, underlying conditions and interventions.

Patients	325
Mean age (years)	40.1 + /- 15.1
Gender (F/M [%])	229/96 [70.5/29.5]
Primary pathology (%)	IIH = 97 (29.8) Chiari-Syringomyelia = 61 (18.8) Tumour / SOL = 32 (9.8) Congenital = 18 (5.5) NPH = 15 (4.6) Aqueductal Stenosis = 13 (4.0) LOVA = 10 (3.1) CSF leak = 8 (2.5) Neurovascular = 3 (0.9) Traumatic brain injury = 3 (0.9) Non-specific = 65 (20.0)
Median days between ICPM and MRI (IQR)	31 (7–60)
Prior intervention (%)	None = 181 (55.7) VPS = 88 (27.1) LPS = 17 (5.2) FMD = 6 (1.8) VSS = 5 (1.5) ETV = 3 (0.9) CFO = 3 (0.9) VAS = 2 (0.6) CPS = 2 (0.6) EVD = 2 (0.6) Multiple = 16 (4.9)
Surgical intervention following ICP / MRI (%)	No further surgical intervention = 239 (73.5) VPS = 59 (18.1) LPS = 6 (1.8) LD = 5 (1.5) FMD = 5 (1.5) CFO = 3 (0.9) VSS = 2 (0.6) EVD = 1 (0.3) VAS = 1 (0.3) SPS = 1 (0.3) Multiple = 3 (0.9)

CFO cyst fenestration with Ommaya reservoir insertion; CPS cysto-peritoneal shunt; ETV endoscopic third ventriculostomy; EVD external ventricular drain ;FMD foramen magnum decompression; ICPM intracranial pressure monitoring; IIH = idiopathic intracranial hypertension; IQR interquartile range; LD lumbar drain;LOVA long standing overt ventriculomegaly in adults; LPS lumboperitoneal shunt; NPH normal pressure hydrocephalus; SOL space-occupying lesion; SPS syringo-pleural shunt; VAS ventriculo-atrial shunt; VPS ventriculoperitoneal shunt; VSS venous sinus stenting.