CASE 836 Published on 22.03.2001

Fetal MRI in holoprosencephaly and mega cisterna magna

Section

Neuroradiology

Case Type

Clinical Cases

Authors

R.N.Sener

Patient

22 years, female

Categories

No Area of Interest ; Imaging Technique MR

No Procedure ; No Special Focus ;

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Clinical History

Fetal MRI

Imaging Findings

A 22-year-old pregnant woman underwent an ultrasound examination for evaluation of her fetus at the 24th week of gestation. Enlarged lateral ventricles, and enlarged posterior fossa were noted. The woman was referred for intrauterine MRI. On MRI, the HASTE (half-Fourier single-shot turbo spin echo), and the TRUFI (True FISP = fast imaging with steady state precession) sequences were used. In each of these fast imaging sequences acquisition time was 11 seconds.

Discussion

Fetal fast MRI with HASTE or TRUFI sequences provides evaluation of especially the brain in a quite detailed fashion. Fetal MRI could be a complementary method to fetal ultrasound studies with respect to confirming the findings especially in brain malformations. In the current fetus, fusion of the frontal lobes, pathognomonic finding for holoposencephaly, was well demonstrated by intrauterine MRI. Lateral ventricles were dilated, and they appeared as a single ventricle. Presence of relatively well developed hemispheres suggested lobar type of holoposencephaly, compared to more severe types referred to as semilobar, and alobar holoposencephaly. An additional finding was mega cisterna magna. Demonstration of a normal 4th ventricule excluded Dandy-Walker malformation. It is known that in some patients with mega cisterna magna supratentorial anomalies can occur, however, coexistence of a severe anomaly like holoprosencephaly is unusual. The pregnancy was terminated, and the diagnosis of holoprosencephaly was confirmed with an impression favoring lobar form of the anomaly.

Differential Diagnosis List

holoprosencephaly and mega cisterna magna

Final Diagnosis

holoprosencephaly and mega cisterna magna

References

[1] Barkovich AJ. Pediatric neuroimaging. Lippincott Williams & Wilkins,
Philadelphia (2000).

[2] Levine D, Barnes PD, Sher S, Semelka RC, Li W, McArdle CR, Worawattanakul S, Edelman RR. Fetal fast MR imaging: reproducibility, technical quality, and conspicuity of anatomy.
Radiology. 1998 Feb;206(2):549-54. (PMID: 9457211)

[3] Vimercati A, Greco P, Vera L, Resta M, Selvaggi L. The diagnostic role of "in utero" magnetic resonance imaging.
J Perinat Med. 1999;27(4):303-8. (PMID: 10560083)

[4] Sener RN.
Holoprosencephaly manifesting with fusion of the gyri cinguli.
J Neuroradiol. 1998 Mar;25(1):52-4. (PMID: 9585632)

[5] Rollins N, Joglar J, Perlman J.
Coexistent holoprosencephaly and Chiari II malformation.
AJNR Am J Neuroradiol. 1999 Oct;20(9):1678-81. (PMID: 10543640)

Case information

URL:	https://www.eurorad.org/case/836
DOI:	10.1594/EURORAD/CASE.836
ISSN:	1563-4086

Figure 1

Fetal MRI

HASTE (half-Fourier single-shot turbo spin echo) sequence. Sagittal view demonstrates mega cisterna magna posterior to and over the cerebellum. The 4th ventricle is normal, excluding Dandy-Walker malformation.

Transverse HASTE image reveals fusion of the two hemispheres, characteristic for holoprosencephaly. Enlarged lateral ventricle, and mega cisterna magna are partly seen in this section.

Transverse HASTE image at a lower section again reveals fusion of the frontal lobes, large lateral ventricles, and mega cisterna magna.

TRUFI (True FISP = fast imaging with steady state precession) sequence. Coronal view demostrates that the lateral ventricles have a single cavity (monoventricle). Fusion of the two hemispheres is seen. The cerebral hemispheres are relatively well developed indicating lobar form of holoprosencephaly.