CASE 841 Published on 27.03.2001

CISS sequence in endoscopic aqueductoplasty

Section

Neuroradiology

Case Type

Clinical Cases

Authors

R.N.Sener

Patient

10 years, male

Categories

No Area of Interest ; Imaging Technique MR

No Procedure ; No Special Focus ;

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Clinical History

Endoscopic aqueductoplasty for aqueductal stenosis secondary to a aqueductal web.

Imaging Findings

The patient presented with signs and symptoms of increased intracranial pressure. CT and MR imaging studies revealed hydrocephalus, and the findings were in favor of aqueductal stenosis. Endoscopic aqueductoplasty was performed, and a web was perforated. Immediately after this procedure, a MRI examination was performed to monitor the patency of the aqueduct. Besides T1 and T2-weighted images, the CISS sequence (constructive interference of steady state), which is a gradient-echo sequence, was applied. Slice thickness was 1 mm in the CISS sequence.

Discussion

Several MRI techniques have previously been used for monitoring the patency of the aqueduct after endoscopic aqueductoplasty. These have included T1 and T2-weighted images, and flow studies by cine phase-contrast imaging. Same techniques have also been applied after endoscopic third ventriculostomy. We have recently started using a relatively new gradient-echo sequence called CISS imaging. CISS sequence appears to be superior to T1 and T2-weighted MRI for detecting the efficiency of neuroendoscopic procedures directed to the aqueduct, and to the floor of the third ventricle. Comparison of T1 and T2-weighted images with the CISS sequence are provided in detail in the figure legends.

Differential Diagnosis List

Efficient endoscopic aqueductoplasty shown by CISS imaging

Final Diagnosis

Efficient endoscopic aqueductoplasty shown by CISS imaging

References

[1] Schroeder HW, Schweim C, Schweim KH, Gaab MR. Analysis of aqueductal cerebrospinal fluid flow after endoscopic aqueductoplasty by using cine phase-contrast magnetic resonance imaging.
J Neurosurg. 2000 Aug;93(2):237-44. (PMID: 10930009)

[2] Schroeder HW, Gaab MR. Endoscopic aqueductoplasty: technique and results.
Neurosurgery. 1999 Sep;45(3):508-15. (PMID: 10493373)

[3] Kulkarni AV, Drake JM, Armstrong DC, Dirks PB. Imaging correlates of successful endoscopic third ventriculostomy.
J Neurosurg. 2000 Jun;92(6):915-9. (PMID: 10839249)

[4] Wilcock DJ, Jaspan T, Worthington BS, Punt J. Neuro-endoscopic third ventriculostomy: evaluation with magnetic resonance imaging.
Clin Radiol. 1997 Jan;52(1):50-4. (PMID: 9022581)

[5] Laitt RD, Mallucci CL, Jaspan T, McConachie NS, Vloeberghs M, Punt J. Constructive interference in steady-state 3D Fourier-transform MRI in the management of hydrocephalus and third ventriculostomy.
Neuroradiology. 1999 Feb;41(2):117-23. (PMID: 10090604)

Case information

URL:	https://eurorad.org/case/841
DOI:	10.1594/EURORAD/CASE.841
ISSN:	1563-4086

Figure 1

Endoscopic aqueductoplasty

T1-weighted image is negative for detection of presence or absence of flow through the aqueduct.

T2-weighted image, too, can not display if aqueductal flow is present or not. Note a hyperintense area in the corpus callosum secondary to the endoscopic intervention.

CISS (constructive interference of steady state) image clearly displays presence of aqueductal jet flow as a gray line (arrow). Flow through the aqueduct should be expected to improve by time, as the images were obtained immediately after the endoscopic procedure.