Third‐trimester fetal MRI in isolated 10‐ to 12‐mm ventriculomegaly: is it worth it?

Abstract

Objective The justification for magnetic resonance imaging (MRI) in isolated mild ventriculomegaly remains controversial. This study was undertaken to evaluate the contribution of third-trimester MRI in isolated 10-to 12-mm fetal ventriculomegaly.Design Observational prospective cohort study.Setting Universitary prenatal reference centre.Population From February 2000 to May 2005, we prospectively collected data concerning fetuses referred to us for cerebral MRI following detection of ventriculomegaly by ultrasound scan (n = 310).Methods Among these, we identified and analysed those cases in which ventriculomegaly was isolated and did not exceed 12 mm in ultrasound examinations prior to MRI scan (n = 185).Main outcome measure Cases in which MRI provided additional information that was likely to have an impact on prenatal management were detailed.Results During the study period, 310 MRI were performed because of fetal ventriculomegaly. Hundred and eighty-five were suspected to be isolated 10-to 12-mm ventriculomegalies in ultrasound scan and formed our database. MRI confirmed the 10-to 12-mm isolated fetal ventriculomegaly in 106 cases (57.3%) and found other abnormalities in 5 (4.7%) of these 106 cases. MRI found ventricular measurement to be less than 10 mm in 43 cases (23.3%) and more than 12 mm in 36 cases (19.4%). Among these 36 fetuses with ventricle size more than 12 mm, 6 (16.7%) had other abnormalities, whereas MRI did not find other abnormalities in the 43 cases with ventricle size below 10 mm.Conclusion Before advantages of MRI to ultrasound examination can be demonstrated, it seems reasonable that MRI should remain an investigational tool, restricted to selected clinical situations in which the results are expected to modify case management. Where ultrasound scan suspects isolated ventriculomegaly of 10 to 12 mm, our data suggest that when the finding is confirmed with MRI this could be expected in around 5% of cases. Therefore, the policy of routine MRI in such cases should depend on prenatal centres' priorities.

A Prospective Study of Fetuses with Isolated Ventriculomegaly Investigated by Antenatal Sonography and In Utero MR Imaging

“…Early work by Garel and Alberti 17 seemed to support that assumption, but a more recent publication, including the same author, showed the opposite conclusion. 18 The retrospective analysis of Salomon et al 18 included 185 thirdtrimester fetuses who had isolated mild VM (ie, 10-to 12-mm trigones) as measured on sonography. They found that the most frequent disagreement between sonography and iuMR was in the classification of the degree of VM.…”

The significance of fetal ventriculomegaly: etiology, short‐ and long‐term outcomes

“…The value of in utero MRI in cases of ultrasound diagnosed fetal isolated VM is addressed by a number of recent studies (Malinger et al, 2004;Valsky et al, 2004;Ouahba et al, 2006;Salomon et al, 2006;Benacerraf et al, 2007;Glenn and Barkovich, 2006a;Glenn and Barkovich, 2006b;Morris et al, 2007). The percentage of additional abnormalities diagnosed by MRI ranges from 5% (Salomon et al, 2006) to 50% (Morris et al, 2007).…”

“…VM is severe when the measurement of the ventricular width is >15 mm, or ≥15 mm according to different authors (Den Hollander et al, 1998;Graham et al, 2001;Gaglioti et al, 2005;Breeze et al, 2007); it is defined mild or borderline when the measurement is less (Wax et al, 2003;Wyldes and Watkinson, 2004). Recent data would suggest to further divide borderline VM into mild (10-12 mm) and moderate (>12-15 mm) (Signorelli et al, 2004;Gaglioti et al, 2005;Salomon et al, 2006;Falip et al, 2007).…”

“…The value of in utero MRI in cases of ultrasound diagnosed fetal isolated VM is addressed by a number of recent studies (Malinger et al, 2004;Valsky et al, 2004;Ouahba et al, 2006;Salomon et al, 2006;Benacerraf et al, 2007;Glenn and Barkovich, 2006a;Glenn and Barkovich, 2006b;Morris et al, 2007). The percentage of additional abnormalities diagnosed by MRI ranges from 5% (Salomon et al, 2006) to 50% (Morris et al, 2007). Such large differences among studies could be due to the variable standards of ultrasound or MRI, but could also be explained by the type of malformations observed; in fact, it seems that MRI is superior to ultrasound in detecting parenchymal damage, migrational abnormalities, infarctions, germinal matrix hemorrhage and intraventricular hemorrhage, but not other malformations for which a dedicated neurosonographic examination could be superior (Malinger et al, 2004).…”

Fetal mild ventriculomegaly: still a challenging problem

“…The use of magnetic resonance imaging (MRI) has been advocated as a useful tool in evaluating fetuses with mild VM [2,19,22,26]; it adds important information in 6%-10% of the cases, particularly in recognizing associated cortical anomalies. For this reason the appropriate time to perform MRI is in the third trimester; it must be done by experienced operators in reference centers, following an accurate neurosonography in order to avoid useless request of such a sophisticated and expansive procedure.…”