Answer for BIR CoW 03 Aug 2025
Shunt malfunction with hydrocephalus
Findings
Bilateral lateral, 3rd and 4th ventricles appear dilated. Evan’s index - 0.41. Third ventricle measures 11mm. Fourth ventricle measures 14 mm. Left ventriculo-peritoneal shunt noted with tip in the body of the left lateral ventricle. PC CSF flow velocity imaging was done: CSF flow across aqueduct showed flow in the aqueduct and foramen of magendie region. CSF flow quantification revealed relatively increased stroke volume and peak velocity in the aqueduct. Peak Systolic Velocity - 9.3 cm/sec. Stroke Volume - 95 Micro litres. CSF flow across the shunt showed no flow in the shunt tube. Confluent T2 / FLAIR hyperintensities were noted in bilateral periventricular and deep white matter. Small vessel ischemic changes were observed in Fazeka’s grade III. Chronic lacunar infarcts noted in the right ganglio capsular region.
Diagnosis : PC CSF velocity imaging across shunt reveals shunt malfunction with no flow across the shunt. PC CSF flow imaging revealed significantly increased peak systolic velocity and stroke volume across the aqueduct.
Discussion
A CSF flow study MRI is a specialized MRI technique, most often using phase-contrast (PC) sequences, to visualize and measure cerebrospinal fluid (CSF) movement in the brain and spine. It provides both qualitative and quantitative data on CSF dynamics, aiding in the diagnosis of:
Normal Pressure Hydrocephalus (NPH) - Enlarged ventricles + hyperdynamic CSF flow (↑ SV & peak velocity)
Aqueductal stenosis - Low stroke volume & low velocities
Chiari malformation - Altered flow at foramen magnum; reduced or turbulent flow
Shunt evaluation - Patency assessed by presence/absence of flow
References
[1] MRI Brain CSF Flow Study Explained - Cadabam's Diagnostics https://cadabamsdiagnostics.com/bangalore/mri-scan/csf-flow-study-mri-scan
[2] Cerebrospinal fluid flow imaging by using phase-contrast MR ... https://pmc.ncbi.nlm.nih.gov/articles/PMC3473435/
[3] Phase-Contrast MRI CSF Flow Measurements for the Diagnosis of ... https://ajronline.org/doi/10.2214/AJR.16.16995
[4] Interpretation and value of MR CSF flow studies for paediatric ... https://sajr.org.za/index.php/sajr/article/view/208/228
Findings
Bilateral lateral, 3rd and 4th ventricles appear dilated. Evan’s index - 0.41. Third ventricle measures 11mm. Fourth ventricle measures 14 mm. Left ventriculo-peritoneal shunt noted with tip in the body of the left lateral ventricle. PC CSF flow velocity imaging was done: CSF flow across aqueduct showed flow in the aqueduct and foramen of magendie region. CSF flow quantification revealed relatively increased stroke volume and peak velocity in the aqueduct. Peak Systolic Velocity - 9.3 cm/sec. Stroke Volume - 95 Micro litres. CSF flow across the shunt showed no flow in the shunt tube. Confluent T2 / FLAIR hyperintensities were noted in bilateral periventricular and deep white matter. Small vessel ischemic changes were observed in Fazeka’s grade III. Chronic lacunar infarcts noted in the right ganglio capsular region.
Diagnosis : PC CSF velocity imaging across shunt reveals shunt malfunction with no flow across the shunt. PC CSF flow imaging revealed significantly increased peak systolic velocity and stroke volume across the aqueduct.
Discussion
A CSF flow study MRI is a specialized MRI technique, most often using phase-contrast (PC) sequences, to visualize and measure cerebrospinal fluid (CSF) movement in the brain and spine. It provides both qualitative and quantitative data on CSF dynamics, aiding in the diagnosis of:
- Communicating vs. non-communicating hydrocephalus
- Chiari malformation
- Aqueductal stenosis
- Shunt malfunction
- Primary method: Phase-contrast MRI
- Flow parameters detected: speed, direction, and pattern (normal, turbulent, or absent)
- Flow direction representation:
- Cranial flow: shades of black on phase images
- Caudal flow: shades of white on phase images
- Imaging planes:
- Axial plane – for flow quantification (through-plane velocity encoding in craniocaudal direction)
- Sagittal plane – for qualitative evaluation (in-plane velocity encoding in craniocaudal direction)
- Confirm velocity encoding (VENC) is appropriate (typically 5–20 cm/s for CSF)
- Assess both magnitude and phase images
- Peak velocity: Normal = 5–8 cm/s across the cerebral aqueduct
- Stroke volume (SV): >42 µL often indicates hyperdynamic flow (e.g., in normal pressure hydrocephalus)
- Normal CSF pulsatility: biphasic waveform (to-and-fro motion) over the cardiac cycle
- Evaluate:
- Shape
- Amplitude
- Symmetry
(Changes may indicate pathology)
Normal Pressure Hydrocephalus (NPH) - Enlarged ventricles + hyperdynamic CSF flow (↑ SV & peak velocity)
Aqueductal stenosis - Low stroke volume & low velocities
Chiari malformation - Altered flow at foramen magnum; reduced or turbulent flow
Shunt evaluation - Patency assessed by presence/absence of flow
References
[1] MRI Brain CSF Flow Study Explained - Cadabam's Diagnostics https://cadabamsdiagnostics.com/bangalore/mri-scan/csf-flow-study-mri-scan
[2] Cerebrospinal fluid flow imaging by using phase-contrast MR ... https://pmc.ncbi.nlm.nih.gov/articles/PMC3473435/
[3] Phase-Contrast MRI CSF Flow Measurements for the Diagnosis of ... https://ajronline.org/doi/10.2214/AJR.16.16995
[4] Interpretation and value of MR CSF flow studies for paediatric ... https://sajr.org.za/index.php/sajr/article/view/208/228
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!