Reducing radiation exposure in newborns with birth head trauma

Full Text

Introduction

Reduction of radiation load in children with birth injuries of the head has recently become increasingly practical [1–4]. This is mainly attributable to two factors. First, modern medical care standards for children with head traumas recommend extensive use of skull radiography and computed tomography [5–7]. Lesions of the skull bones or intracranial hematomas are indications of repeated use of radiation diagnostic methods. Second, in newborns and young children, the use of these methods is associated with a high risk of radiation-related complications [8–12]. According to J.D. Mathews et al., a delayed risk of developing cancer in patients exposed to ionizing radiation during childhood is 25% greater than that in the general population [13]. Therefore, non-radial technologies for visualizing skull bones and intracranial spaces are particularly relevant [1, 4]. Most often, this need arises with cephalhematomas (CHs), the frequency of which varies between 0.1% and 10%, according to literature. A majority of these spontaneously resolve without consequences. However, in 3%–20% cases, CHs are combined with linear cranial vault bone fractures and in 2%–5% cases, they are accompanied by epidural hematomas (EH) [14–17]. An early diagnosis of CH is crucial. The reliability of neurological status interpretations is low in newborns. Fractures of the cranial vault bones and EH are often accompanied by satisfactory clinical status of newborns [18]. The most effective methods of neuroimaging are characterized by minimal invasiveness, wide accessibility, and possibility of conducting an examination without taking a newborn from an incubator couveuse. One such method is ultrasonography (US) [1, 4, 17, 19, 20].

Aim. This study aimed at assessing the possibility of using US for diagnosing fractures of the skull vault bones and epidural hematomas in newborns with CH and ensuring a reduction in the radiation load in children with birth injuries of the head.

Materials and methods

The study was performed in maternity hospital No 10 and the city children’s hospital No 1 of Saint Petersburg from September 2014 to February 2017. Totally, 449 newborns with CH were examined in the maternity hospital: 396 (88.2%) newborns had unilateral parietal CHs, 42 (9.4%) had bilateral parietal CHs, 6 (1.3%) had bilateral parietal CHs combined with occipital ones, and 5 (1.1%) had isolated occipital CHs. All patients with CHs underwent transcranial and transfontanellar US (TTUS) to detect intracranial changes and skull US to assess the CH region bone condition (according to the methods of A.S. Iov [1996]).

When examining newborns with a scalp birth trauma (e.g., CH), evaluating the intracranial condition directly in the zone of external damage was particularly important. A widely used transfontanellar US is incapable of solving this problem; the main disadvantages of this method are as follows: 1) inability to assess the intracranial state in areas directly located under the cranial vault bones (in zones where the meningeal hematomas are most often localized); 2) insufficiency of visualization of the midbrain (lack of reliable US-criteria of dislocations and cerebral edema); 3) dependence on the anterior fontanel size; and 4) inability to perform differential diagnosis of pathological conditions in the convective-parasagittal region (subdural clusters/external hydrocephalus) when scanning with only one probe (sector/microconvex).

Using standard TTUS, scanning is performed through the fontanel and squamosa of the temporal bones with the obligatory application of two probes (sector/microconvex and linear). For transfontanellar scanning, multifrequency probes (7–12 MHz, microconvex and linear), and for transtemporal scanning, multifrequency sector probes (2–4 MHz) were used. Figure 1 shows the schematic orientation of the scan planes at TTUS. It is demonstrated that the blind zone visualization, characteristic for transfontanellar US, is provided by the transtemporal horizontal planes H0, H1, and H2.

 

Fig. 1. Scheme of orientation and designation of the scanning planes for transcranial and transfontanellar ultrasonography: a — sagittal and horizontal planes; b — frontal planes

 

When performing TTUS in children with parietal CH, the intracranial space in the CH region is the area of interest, as visualized during scanning through the opposite temporal bone (Figure 2).

 

Fig. 2. Significance of transtemporal ultrasonography scanning in cephalhematomas: a — a newborn with a right parietal bone cephalhematoma; b — the study scheme; the probe is located on the opposite side of the cephalhematoma; the intracranial space in the region of the cephalhematoma is assessed; c — an ultrasonographic image variant without any signs of meningeal hematoma (the brain is attached to the inner bone plate); d — an ultrasonographic image variant with signs of meningeal hematoma (a biconvex hyperechoic object between the bone and the brain)

 

When conducting skull US, a linear multifrequency probe (5–10 MHz) was mounted on the CH region and longitudinal and transverse scanning was performed over the entire CH area. As shown in Figure 3, the hyperechoic line nearest to the probe represents the image of the skin, the line following it represents the image of the bone, and the hypoechoic soft tissue lies between the two (subcutaneous fatty tissue, aponeurosis) (Figure 3).

 

Fig. 3. Scalp and skull ultrasonography under normal conditions: 1 — skin, 2 — subcutaneous tissue, 3 — bone, and 4 — reverberation artifacts

 

In cases of linear skull fractures, interruption of the hyperechoic bone pattern was noted; the “hyperechoic mark” was located under the fracture region (Figure 4). It is noteworthy that with US, a linear fracture looks identical to a normal skull suture. In case of suspected fractures, one should ensure that the probe is not located above the cranial suture.

 

Fig. 4. Ultrasonographic craniography in the cephalhematoma region: a — the norm, no fracture signs (bone continuity is not violated); b — signs of parietal bone linear fracture (bone continuity is violated, the “hyperechoic mark” phenomenon is immediately revealed under the fracture)

 

Children who showed signs of cranial vault bone fractures and EH on US in the maternity hospital were transferred to the Children’s hospital No 1 (17 patients), where they underwent skull X-ray examination and/or CT of the head. All patient representatives agreed for the examination, participation, and processing of personal data for this study.

Results and discussion

In the parietal region CT of the patients (n = 444), 17 (3.8%) had US signs of parietal bone linear fracture on the CH side. Five (1.1%) patients had EH on the fracture side. EHs were visible only through the transtemporal access, reconfirming the low efficiency of the transfontanellar US in diagnosing meningeal convexital hematomas. The presence of a fracture and EH did not depend on the CH size. In cases of occipital CHs (11 patients), occipital fractures and intracranial hematomas were not detected. EHs were confirmed using CT in all cases; linear fractures were confirmed in 16 (94%) cases (Figures 5 and 6).

 

Fig. 5. Spiral computed tomogram of the skull. Linear fracture with lacunar craniopathy. a — top view; b — side view

 

Fig. 6. Cephalhematoma associated with epidural hematoma and linear parietal bone fracture, 5-day-old newborn, а — transcranial and transfontanellar ultrasonography, transtemporal scanning, and visualized subperiosteal and epidural hematomas; b — skull ultrasonography (right parietal bone linear fracture); c — computed tomogram of the head, confirming ultrasonography data

 

The present results showed a high efficiency of skull US in diagnosing cranial vault bone fractures and that of TTUS in diagnosing meningeal hematomas in newborns with CHs.

In 69% patients (11 newborns), the fractures were combined with US and/or CT parietal bone lacunar craniopathy (LC) signs. LC is a single or multiple rounded defect of the cranial vault bones (often parietal) that is ossified during the first few months of life. Isolated LC does not require special treatment. Clinical signs of LC are softness and thinning of the parietal bones (symptom of a “felt hat”); less commonly, they are palpable rounded bone defects. US signs of LC include local bone thinning areas without interruption to its hyperechoic pattern. The data obtained suggest that parietal bone LC increases the risk of linear fractures even during physiological labor.

Conclusion

Skull, transcranial, and transfontanellar ultrasonography enabled the accomplishment of a crucial practical task for modern medicine, that is, the significant increase in the availability of visualization of fractures of the skull bones and meningeal hematomas in newborns, while reducing the use of methods involving radiation.

Funding and conflict of interest

No funding was received for this study. The authors declare no obvious or potential conflicts of interest related to the publication of this article.

About the authors

Irina A. Kriukova

North-Western State Medical University n.a. I.I. Mechnikov

Author for correspondence.
Email: i_krukova@mail.ru

MD, PhD, neurologist, sonologist, assistant

Russian Federation, 41, Kirochnaya street, Saint-Petersburg, 191015

Evgeniy Y. Kriukov

North-Western State Medical University n.a. I.I. Mechnikov; Children City Hospital No 1

Email: e.krukov@mail.ru

MD, PhD, neurosurgeon, sonologist, head of the Department of Pediatric Neurology and Neurosurgery of North-Western State Medical University n.a. I.I. Mechnikov. Children City Hospital No 1

Russian Federation, 41, Kirochnaya street, Saint-Petersburg, 191015;  Saint-Petersburg

Danil A. Kozyrev

Children City Hospital No 1

Email: nil_dk@mail.ru

MD, neurosurgeon, sonologist

Russian Federation, Saint Petersburg

Semen A. Sotniкov

North-Western State Medical University n.a. I.I. Mechnikov; Children City Hospital No 1

Email: sot-sem@yandex.ru

MD, neurosurgeon, sonologist, junior researcher at the research laboratory “Innovative technologies of medical navigation” at North-Western State Medical University n.a. I.I. Mechnikov

Russian Federation, 41, Kirochnaya street, Saint-Petersburg, 191015;  Saint-Petersburg

Dmitriy A. Iova

North-Western State Medical University n.a. I.I. Mechnikov

Email: iova@rnova.ru

MD, neurosurgeon, sonologist, junior researcher at the research laboratory “Innovative technologies of medical navigation” at North-Western State Medical University n.a. I.I. Mechnikov

Russian Federation, 41, Kirochnaya street, Saint-Petersburg, 191015

Ivan N. Usenko

North-Western State Medical University n.a. I.I. Mechnikov; Saint Petersburg State Pediatric Medical University

Email: ivan_usenko91@mail.ru

MD, neurosurgeon, Saint Petersburg State Pediatric Medical University

Russian Federation, 41, Kirochnaya street, Saint-Petersburg, 191015; 2, Litovskay street, Saint-Peterburg, 194100

Аlexandеr S. Iova

North-Western State Medical University n.a. I.I. Mechnikov; Children City Hospital No 1; Almazov National Medical Research Centre

Email: a_iova@mail.ru

MD, PhD, professor, neurosurgeon, sonologist, professor of the department of pediatric neurology and neurosurgery; head of laboratory “Innovative technologies of medical navigation” at St. Petersburg North-Western State Medical University n.a. I.I. Mechnikov, head of laboratory “Innovative technologies of medical navigation” at St. Petersburg North-Western State Medical University n.a. I.I. Mechnikov, head of research laboratory “Perinatal Neurosurgery” at Almazov National Medical Research Centre

Russian Federation, 41, Kirochnaya street, Saint-Petersburg, 191015; Saint-Petersburg; 2 Akkuratova str., Saint- Petersburg, 197341

References

Supplementary files