Get a radiograph perpendicular to the valve, identify the valve type, confirm orientation with its marker, then read the setting against the manufacturer template. Report the valve type and the setting.
Obliquity distorts the dial and hides orientation markers. Repeat a centred view perpendicular to the valve rather than guess.
A flipped image reverses the reading on Hakim, Strata and Miethke valves. Check the orientation marker first.
Compare with the prior shunt series; settings change deliberately and after MRI.
Medtronic Strata
Figure · click to enlarge
Strata valve at performance levels 0.5 to 2.5. The arrow marks the notch in the dark dial. Source: Lollis SS et al. AJNR 2010;31:1343–6, Fig 2; via UW Emergency Radiology.
Find the two small round markers beside the dial; the notch in the dark dial points to the performance level.
MRI can change the setting: confirm after every MRI.
Codman Hakim
Figure · click to enlarge
A, Hakim valve radiograph. B, Manufacturer X-ray setting template: place the round indicator marker on the right, then read the notch in the white ring. Source: Lollis SS et al. AJNR 2010;31:1343–6, Fig 1; via UW Emergency Radiology.
The round indicator marker belongs on the right-hand side. If it is on the left, the image is reversed: flip it before reading.
The notch in the radiopaque ring points to the setting: 30–200 mmH₂O in 10 mmH₂O steps (18 settings), arranged clockwise from 30 at 3 o'clock.
MRI can reset the valve: confirm after every MRI.
Codman Certas / Certas Plus
Figure · click to enlarge
Certas Plus: the red circle marks the right-hand X-ray marker; the green box marks the setting indicator at each of positions 1–8. Source: Codman Certas Plus X-ray procedure guide (Johnson & Johnson, 2015); via UW Emergency Radiology.
Orient the small round marker to the upper right.
Read which position the T-shaped setting indicator points to.
Position
1
2
3
4
5
6
7
8
mmH₂O
25
50
80
110
145
180
215
Virtual off (>400)
Sophysa (Sophy and Polaris)
Figure · click to enlarge
A, Sophy valve: rotor (two white squares) in positions 1–8 with opening pressures. B, Polaris valve: positions 1–5. Source: Lollis SS et al. AJNR 2010;31:1343–6, Fig 3; via UW Emergency Radiology.
The rotor is the pair of radiopaque squares; its angle gives the position.
Sophy standard pressure model (8 positions): 30, 50, 70, 90, 110, 140, 170, 200 mmH₂O.
Polaris: position 1 is nearest the inlet; the dots beside the inlet give the model, which sets the pressures (table). It has a magnetic lock, but recheck after MRI.
Polaris model (dots by inlet)
Pos 1
Pos 2
Pos 3
Pos 4
Pos 5
SPV-140 (no dot)
10
40
80
110
140
SPV (1 dot)
30
70
110
150
200
SPV-300 (2 dots)
50
100
150
220
300
SPV-400 (3 dots)
80
150
230
330
400
Aesculap / Miethke proGAV
Figure · click to enlarge
A, proGAV radiograph. B, Manufacturer template: the rotor tip shows the opening pressure (0–20 cmH₂O); note the orientation of the flat side. C, Gravitational unit coding. Source: Lollis SS et al. AJNR 2010;31:1343–6, Fig 4; via UW Emergency Radiology.
Lay the template over the valve with the flat side matching; the rotor tip points to the adjustable unit setting, 0–20 cmH₂O.
The fixed gravitational unit adds opening pressure in the upright position. Its size and number of rings give the value (table).
Report both: adjustable setting and gravitational unit.
Gravitational unit
Size / rings
Added upright pressure
Small
No ring
10 cmH₂O
Large
No ring
15 cmH₂O
Large
1 ring
20 cmH₂O
Large
2 rings
25 cmH₂O
Large
3 rings
30 cmH₂O
Large
4 rings
35 cmH₂O
Aesculap / Miethke proSA
Figure · click to enlarge
proSA (programmable shunt assistant) template and radiograph. The cut-out marks orientation; the rotor tip gives the setting on a 0–40 cmH₂O scale. Source: Aesculap; via UW Emergency Radiology.
Align the cut-out in the outer ring, then read where the rotor tip points on the 0–40 cmH₂O scale.
The proSA is the adjustable gravitational unit, usually paired with a proGAV or another valve: report both components.
MRI and the setting
Valve
After MRI
Codman Hakim
Reset possible: check
Medtronic Strata
Change possible: check
Sophysa Sophy
Change possible: check
Codman Certas Plus
Designed to resist; confirm
Sophysa Polaris
Magnetic lock; confirm
Aesculap proGAV 2.0 / proSA
Locked; confirm if in doubt
Figures reproduced from Lollis et al. (AJNR 2010), Codman and Aesculap materials as collected by the UW Emergency Radiology Trauma Radiology Reference Resource. Follow the current manufacturer instructions for the specific model.
Radessential summarizes published classification systems for practicing radiologists. Summaries are condensed; confirm details against the cited source before relying on them for patient care.
RadEssentialReading-room reference