Table of contents:

1. Medical US examination
2. MR (Magnetic Resonance Imaging)
3. Usefulness of MR in practice
4. Is it worth deepening the diagnosis with an MR examination?

One of the largest groups of developmental disorders in children is congenital malformations of the central nervous system (CNS). This term includes pathologies such as malformations of the brain and spinal cord, which in a significant number of cases are complex defects. This is due to the fact that events that cause abnormalities in the development of the CNS usually lead to an abnormal situation within more than just one anatomical structure. In Poland, the incidence of congenital CNS abnormalities is estimated at about 16 per 10,000 births, and in 40 per cent of cases, they end in death during the child's first year of life. In the remaining cases, diverse and severe neurological disorders can be expected during development - including mental retardation and epilepsy.

Medical US study

For a very long time,medical ultrasound (US) was the primary (and only) imaging method available for diagnosing congenital malformations. To this day, it remains the cornerstone of the diagnostic process, but like any examination method, Medical US also has certain limitations, and therefore, even with specialised and technologically advanced equipment (even allowing 3D and 4D imaging), it is unlikely that all fetal abnormalities will be detected.

MR (Magnetic Resonance Imaging)

The use of MR (magnetic resonance imaging) to diagnose congenital malformations of the CNS, is due to the fact that the Medical US examination has certain limitations. As medical practice indicates, MR is free of this risk of error. As early as the 1990s, MR was used as a tool to image the anatomical structures of the CNS of a fetus moving in the womb, but at the time it was used as an experimental study - as it turned out, with very good results.

MRI, photo: panthermedia

However, the specialist community raises the question of the place MR should have in the diagnosis of congenital fetal abnormalities and the aspect of its coverage, i.e. how much it should be used as a screening test and how much it should only be used in specific situations.

Usefulness of MR in practice

Referring to studies carried out between 2008 and 2013 in the Magnetic Resonance Laboratory of the Medical Diagnostic Centres in the Department of Medical Radiology and Radiodiagnosis of the Independent Public Clinical Hospital No. 1 in Zabrze, Prof. S. Szyszko, SUM Katowice, we take a closer look at this widely discussed issue of the usefulness of MR in practice.

During the study, more than 80 fetal MR examinations were performed, among which pregnancies were selected which were referred for further diagnostics for fetal developmental anomalies.

Most often, the reason for referral for in-depth examination and extension of the diagnosis to MR examination is dilatation of the fetal cerebral ventricular system. On the other hand, it is also the most common pathology observed on MR examination. According to the information found in the specialist literature (also worldwide), the results obtained in the course of this study have shown that MR has a greater capacity than Medical US to visualise the pathologies that occur in ventriculomegaly.

With regard to less common defects, such as isolated callosal defects, MR examination was effective enough to visualise pathological changes to a much greater extent than Medical US examination. However, with reference to the world literature, no such confirmation is found - as there are various, divergent reports on the sensitivity of Medical US examination in the diagnosis of callosal body defects.

Specialised literature also shows data on the diagnosis of developmental defects of the posterior cranial fossa using MR. Some publications show the superiority of this method over Medical US examination, highlighting additional details in terms of anatomical anomalies.

Is it worth deepening the diagnosis with MR examination?

Observations showed that fetuses with malformations were confirmed by both Medical US and MR examination. This therefore establishes the complementarity of MR examination with Medical US examination. MR examination can be a useful tool to complement prenatal diagnosis, in particular when Medical US examination detects abnormalities. Moreover, MR is a research tool that significantly increases the precision of thesis or solutions and, moreover, the MR image is so detailed that there are cases in which the thesis based on the Medical US examination may change after the MR image is obtained.

Medical US examinationin pregnancy, photo: panthermedia

A significant advantage of MR examination over Medical US examination has also been observed in the diagnosis of malformations of the corpus callosum.

The topic raised by these studies opens the door to further discussion on the efficacy and validity of using MR in the diagnosis of fetal CNS congenital malformations. As indicated by the studies, in the context of the information found in the world literature, it can be concluded that this examination is highly effective in diagnosis, particularly with regard to suspected developmental disorders. However, this examination is expensive and hence, its use is not so widespread. Moreover, MR examination is regarded as a very useful examination complementary to the diagnosis of Medical US, without taking the place of this examination. Undoubtedly, it is an investigative procedure through which a lot of additional information can be obtained, thus clarifying the diagnosis. [1]

Prenatal diagnosis is a very important part of pregnancy control. The basic examination with which developmental disorders and pathologies on the part of the CNS can be detected is the Medical US examination and its effectiveness is not questioned; however, it is also worth returning to the possibility of deepening the diagnosis, which is provided by the MR examination.