Usefulness of (1) H-MRS in differentiating bilirubin encephalopathy from severe hyperbilirubinemia in neonates

Magnetic resonance spectroscopy and auditory brain-stem response audiometry as predictors of bilirubin-induced neurologic dysfunction in full-term jaundiced neonates

The purpose of this research was to define the functions of MRS and ABR as predictors of bilirubin-induced neurologic dysfunction (BIND) in full-term neonates who required intervention (phototherapy and/or exchange transfusion). This prospective cohort study was done at the NICU of Tanta University Hospitals over a 2-year duration. Fifty-six full-term neonates with pathological unconjugated hyperbilirubinemia were divided according to MRS and ABR findings into 2 groups: group (1) included 26 cases with mild acute bilirubin encephalopathy (BIND-M score 1-4). Group (2) included 30 cases with neonatal hyperbilirubinemia only. In addition, 20 healthy neonates with similar ages were employed as the controls. When compared to group 2 and the control group, group 1's peak-area ratios of NAA/Cr and NAA/Cho were found to be significantly reduced (P < 0.05). As compared to group 2 and the control group, group 1's Lac/Cr ratio was significantly greater (P < 0.05), but the differences were not significant for group 2 when compared to the control group. Waves III and V peak latencies, I-III, and I-V interpeak intervals were significantly prolonged in group 1 in comparison to group 2 and controls (P < 0.05) with no significant difference between group 2 and control group.   Conclusion: When the symptoms of ABE are mild and MRI does not show any evident abnormalities, MRS and ABR are helpful in differentiating individuals with ABE from patients with neonatal hyperbilirubinemia.    Trial registration:  ClinicalTrials.gov , Identifier: NCT06018012. What is Known: • MRS can be used as a diagnostic and prognostic tool for the differential diagnosis of patients with acute bilirubin encephalopathy, from patients with neonatal hyperbilirubinemia What is New: • ABR is a useful diagnostic and prognostic tool in the care and management of neonates with significantly raised bilirubin. It can be used as early predictor of acute bilirubin encephalopathy in the earliest stage of auditory damage caused by bilirubin.

Predictive and diagnostic measures for kernicterus spectrum disorder: a prospective cohort study

BACKGROUND

Kernicterus spectrum disorder (KSD) resulting from neonatal hyperbilirubinemia remains a common cause of cerebral palsy worldwide. This 12-month prospective cohort study followed neonates with hyperbilirubinemia to determine which clinical measures best predict KSD.

METHODS

The study enrolled neonates ≥35 weeks gestation with total serum bilirubin (TSB) ≥ 20 mg/dl admitted to Aminu Kano Hospital, Nigeria. Clinical measures included brain MRI, TSB, modified bilirubin-induced neurologic dysfunction (BIND-M), Barry-Albright Dystonia scale (BAD), auditory brainstem response (ABR), and the modified KSD toolkit. MRI signal alteration of the globus pallidus was scored using the Hyperbilirubinemia Imaging Rating Tool (HIRT).

RESULTS

Of 25 neonates enrolled, 13/25 completed 12-month follow-up and six developed KSD. Neonatal BIND-M ≥ 3 was 100% sensitive and 83% specific for KSD. Neonatal ABR was 83% specific and sensitive for KSD. Neonatal HIRT score of 2 was 67% sensitive and 75% specific for KSD; this increased to 100% specificity and sensitivity at 12 months. BAD ≥ 2 was 100% specific for KSD at 3-12 months, with 50-100% sensitivity.

CONCLUSIONS

Neonatal MRIs do not reliably predict KSD. BIND-M is an excellent screening tool for KSD, while the BAD or HIRT score at 3 or 12 months can confirm KSD, allowing for early diagnosis and intervention.

IMPACT

The first prospective study of children with acute bilirubin encephalopathy evaluating brain MRI findings over the first year of life. Neonatal MRI is not a reliable predictor of kernicterus spectrum disorders (KSD). Brain MRI at 3 or 12 months can confirm KSD. The modified BIND scale obtained at admission for neonatal hyperbilirubinemia is a valuable screening tool to assess risk for developing KSD. The Barry Albright Dystonia scale and brain MRI can be used to establish a diagnosis of KSD in at-risk infants as early as 3 months.

Globus pallidus/putamen T1WI signal intensity ratio in grading and predicting prognosis of neonatal acute bilirubin encephalopathy

Purpose

This study sought to investigate the relationship between the globus pallidus/putamen T1 weighted image (T1WI) signal intensity ratio (G/P ratio) and the acute bilirubin encephalopathy (ABE) in neonates, and to develop a new strategy for the grading and prognosis of ABE based on the G/P ratio.

Methods

A total of 77 full-term neonates with ABE were scored according to bilirubin-induced neurological dysfunction and divided into mild, moderate, and severe groups. Cranial magnetic resonance imaging examinations were performed and the G/P ratio was recorded. The follow-up reexaminations were carried out at 6 months, 1 year, and 2 years after the initial examination. The neonates were then divided into two groups, the good prognosis group and the kernicterus spectrum disorder (KSD) group, according to the evaluation of Gesell Developmental Schedules and Brainstem Audio Electric Potential at 6 months.

Main findings

The differences of G/P ratios were statistically significant, not only among the mild, moderate, and severe ABE groups for the initial examinations but also between the KSD and the good prognosis groups for the follow-up reexaminations. Therefore, the ABE grading model and prognosis predicting model could be established based on the G/P ratio. In the KSD group, the area under the receiver operating characteristic curve of the G/P ratio-based predicting model was 93.5%, the optimal critical point was 1.29, the sensitivity was 88.2%, and the specificity was 93.3%.

Conclusions

The G/P ratio can be used as an indicating parameter for both the clinical grading of neonatal ABE and the assessment of neonatal ABE prognosis. Specifically, the G/P ratio greater than 1.29 indicates a KSD of neonatal ABE.

The differential value of radiomics based on traditional T1-weighted sequences in newborns with hyperbilirubinemia

BACKGROUND

On the basis of visual-dependent reading method, radiological recognition and assessment of neonatal hyperbilirubinemia (NH) or acute bilirubin encephalopathy (ABE) on conventional magnetic resonance imaging (MRI) sequences are challenging. Prior studies had shown that radiomics was possible to characterize ABE-induced intensity and morphological changes on MRI sequences, and it has emerged as a desirable and promising future in quantitative and objective MRI data extraction. To investigate the utility of radiomics based on T1-weighted sequences for identifying neonatal ABE in patients with hyperbilirubinemia and differentiating between those with NH and the normal controls.

METHODS

A total of 88 patients with NH were enrolled, including 50 patients with ABE and 38 ABE-negative individuals, and 70 age-matched normal neonates were included as controls. All participants were divided into training and validation cohorts in a 7:3 ratio. Radiomics features extracted from the basal ganglia of T1-weighted sequences on magnetic resonance imaging were evaluated and selected to set up the prediction model using the K-nearest neighbour-based bagging algorithm. A receiver operating characteristic curve was plotted to assess the differentiating performance of the radiomics-based model.

RESULTS

Four of 744 radiomics features were selected for the diagnostic model of ABE. The radiomics model yielded an area under the curve (AUC) of 0.81 and 0.82 in the training and test cohorts, with accuracy, precision, sensitivity, and specificity of 0.82, 0.80, 0.91, and 0.69 and 0.78, 0.8, 0.8, and 0.75, respectively. Six radiomics features were selected in this model to distinguish those with NH from the normal controls. The AUC for the training cohort was 0.97, with an accuracy of 0.92, a precision of 0.92, a sensitivity of 0.93, and a specificity of 0.90. The performance of the radiomics model was confirmed by testing the test cohort, and the AUC, accuracy, precision, sensitivity, and specificity were 0.97, 0.92, 0.96, 0.89, and 0.95, respectively.

CONCLUSIONS

The proposed radiomics model based on traditional TI-weighted sequences may be used effectively for identifying ABE and even differentiating patients with NH from the normal controls, which can provide microcosmic information beyond experience-dependent vision and potentially assist in clinical diagnosis and treatment.

Imaging of nerve injury in neonatal acute bilirubin encephalopathy using 1H-MRS and Glu-CEST techniques

Objectives

To investigate the significance of proton magnetic resonance spectroscopy (1H-MRS) and glutamate chemical exchange saturation transfer (Glu-CEST) techniques in assessing the condition and prognosis of acute bilirubin encephalopathy patients and to understand the mechanism of nerve injury in this disease.

Materials and methods

From September 2019 to February 2021, 31 neonates with acute bilirubin encephalopathy and 16 healthy neonates were enrolled in this study. All the quantitative results of 1H-MRS, Glu-CEST, and conventional magnetic resonance imaging (MRI) of all neonates were analyzed. The associations between statistically significant indicators of imaging and developmental quotients (DQ) were analyzed.

Results

The 31 cases were assigned to the mild subgroup (n = 21) and moderate and severe subgroup (n = 10) according to the bilirubin-induced neurologic dysfunction (BIND) scores. The case group had elevated Cho and GABA absolute concentrations compared to the normal control group (all p &lt; 0.05). Compared with the normal control group, the absolute concentration of GABA of the moderate and severe subgroup was significantly larger (p &lt; 0.05). Compared with the normal control group, the Glu-CEST% values in the left basal ganglia, right thalamus, left frontal cortex and bilateral medial geniculate body of the case group was significantly larger (all p &lt; 0.05). The moderate and severe subgroup had higher Glu-CEST% values in the left basal ganglia, right thalamus, and bilateral medial geniculate body than the normal control group (all p &lt; 0.05). A negative association was revealed between the DQ scores and the Glu-CEST% values in the left basal ganglia (r = −0.888, p &lt; 0.05).

Conclusion

The combination of 1H-MRS and Glu-CEST techniques can monitor the intracerebral metabolite level of acute bilirubin encephalopathy and evaluate the illness severity.

Bilirubin Encephalopathy

PURPOSE OF REVIEW

Hyperbilirubinemia is commonly seen in neonates. Though hyperbilirubinemia is typically asymptomatic, severe elevation of bilirubin levels can lead to acute bilirubin encephalopathy and progress to kernicterus spectrum disorder, a chronic condition characterized by hearing loss, extrapyramidal dysfunction, ophthalmoplegia, and enamel hypoplasia. Epidemiological data show that the implementation of universal pre-discharge bilirubin screening programs has reduced the rates of hyperbilirubinemia-associated complications. However, acute bilirubin encephalopathy and kernicterus spectrum disorder are still particularly common in low- and middle-income countries.

RECENT FINDINGS

The understanding of the genetic and biochemical processes that increase the susceptibility of defined anatomical areas of the central nervous system to the deleterious effects of bilirubin may facilitate the development of effective treatments for acute bilirubin encephalopathy and kernicterus spectrum disorder. Scoring systems are available for the diagnosis and severity grading of these conditions. The treatment of hyperbilirubinemia in newborns relies on the use of phototherapy and exchange transfusion. However, novel therapeutic options including deep brain stimulation, brain-computer interface, and stem cell transplantation may alleviate the heavy disease burden associated with kernicterus spectrum disorder. Despite improved screening and treatment options, the prevalence of acute bilirubin encephalopathy and kernicterus spectrum disorder remains elevated in low- and middle-income countries. The continued presence and associated long-term disability of these conditions warrant further research to improve their prevention and management.

Detecting acute bilirubin encephalopathy in neonates based on multimodal MRI with deep learning

BACKGROUND

Differentiating acute bilirubin encephalopathy (ABE) from non-ABE in neonates with hyperbilirubinemia (HB) from routine magnetic resonance imaging (MRI) is extremely challenging since both conditions demonstrate similar T1 hyperintensities. To this end, we investigated whether the integration of multimodal MRI from routine clinical scans with deep-learning approaches could improve diagnostic performance.

METHODS

A total of 75 neonates with ABE and 75 neonates with HB (non-ABE) were included in the study. Each patient had three types of multimodal images taken, i.e., a T1-weighted image (T1WI), a T2-weighted image (T2WI), and an apparent diffusion coefficient (ADC) map. The three types of MRI contrasts and their combination were fed into two deep convolutional neural networks (CNNs), i.e., ResNet18 and DenseNet201. The performance of CNNs was compared with a traditional statistical method named logistic regression.

RESULTS

We demonstrated that diagnostic methods with the multimodal data were better than any of the single-modal data. Both CNN models outperformed the logistic regression method. The best performance was achieved by DenseNet201 with the combination of three modalities of T1WI, T2WI, and ADC, with an accuracy of 0.929 ± 0.042 and an area under the curve (AUC) of 0.991 ± 0.007.

CONCLUSIONS

Our study demonstrated that CNN models with multimodal MRI significantly improve the accuracy of diagnosing ABE.

IMPACT

We proposed an efficient strategy of detecting ABE in neonates based on multimodal MRI with deep learning, which achieved an accuracy of 0.929 ± 0.042 and an AUC of 0.991 ± 0.007. We demonstrated the advantage of integrating multimodal MRI in detecting ABE in neonates with HB, using deep-learning models. Our strategy of diagnosing ABE using deep-learning techniques with multimodal MRI from routine clinical scans is potentially applicable to clinical practice.

Detecting neonatal acute bilirubin encephalopathy based on T1-weighted MRI images and learning-based approaches

Background

Neonatal hyperbilirubinemia is a common clinical condition that requires medical attention in newborns, which may develop into acute bilirubin encephalopathy with a significant risk of long-term neurological deficits. The current clinical challenge lies in the separation of acute bilirubin encephalopathy and non-acute bilirubin encephalopathy neonates both with hyperbilirubinemia condition since both of them demonstrated similar T1 hyperintensity and lead to difficulties in clinical diagnosis based on the conventional radiological reading. This study aims to investigate the utility of T1-weighted MRI images for differentiating acute bilirubin encephalopathy and non-acute bilirubin encephalopathy neonates with hyperbilirubinemia.

Methods

3 diagnostic approaches, including a visual inspection, a semi-quantitative method based on normalized the T1-weighted intensities of the globus pallidus and subthalamic nuclei, and a deep learning method with ResNet18 framework were applied to classify 47 acute bilirubin encephalopathy neonates and 32 non-acute bilirubin encephalopathy neonates with hyperbilirubinemia based on T1-weighted images. Chi-squared test and t-test were used to test the significant difference of clinical features between the 2 groups.

Results

The visual inspection got a poor diagnostic accuracy of 53.58 ± 5.71% indicating the difficulty of the challenge in real clinical practice. However, the semi-quantitative approach and ResNet18 achieved a classification accuracy of 62.11 ± 8.03% and 72.15%, respectively, which outperformed visual inspection significantly.

Conclusion

Our study indicates that it is not sufficient to only use T1-weighted MRI images to detect neonates with acute bilirubin encephalopathy. Other more MRI multimodal images combined with T1-weighted MRI images are expected to use to improve the accuracy in future work. However, this study demonstrates that the semi-quantitative measurement based on T1-weighted MRI images is a simple and compromised way to discriminate acute bilirubin encephalopathy and non-acute bilirubin encephalopathy neonates with hyperbilirubinemia, which may be helpful in improving the current manual diagnosis.

Clinicopathological Spectrum of Bilirubin Encephalopathy/Kernicterus

Bilirubin encephalopathy/kernicterus is relatively rare, but continues to occur despite universal newborn screening. What is more interesting is the spectrum of clinical and even neuropathological findings that have been reported in the literature to be associated with bilirubin encephalopathy and kernicterus. In this review, the authors discuss the array of clinicopathological findings reported in the context of bilirubin encephalopathy and kernicterus, as well as the types of diagnostic testing used in patients suspected of having bilirubin encephalopathy or kernicterus. The authors aim to raise the awareness of these features among both pediatric neurologists and neuropathologists.

Clinical study on amplitude integrated electroencephalogram in cerebral injury caused by severe neonatal hyperbilirubinemia

BACKGROUND

This study was designed in order to assess the validity of the use of amplitude-integrated electroencephalogram (aEEG) in cerebral injury caused by severe neonatal hyperbilirubinemia.

METHODS

A total of 56 full-term neonates diagnosed with severe neonatal hyperbilirubinemia and admitted to the NICU of our hospital from July 2013 to December 2014 were continuously selected for the study. The total serum bilirubin (TSB) was higher than 342 μmol/L and was dominated by a higher amount of unconjugated bilirubin. Each patient underwent aEEG monitoring upon admission. And according to the results of the test, they were assigned into an aEEG normal group (N.=38) or an aEEG abnormal group (N.=18). Dynamic monitoring of bilirubin and blood biochemistry was also conducted for all the children after admission. Patients were treated with blue light, anti-infection agents, acidosis correction measures, transfusion exchanges, intravenous drips of albumin or globulin and other specific treatments as needed in each particular case. Brainstem auditory evoked potential (BAEP), MRI examination and a behavioral neurological assessment (NBNA) with 20-item examinations were provided within 4-17 days after admission. Follow-up observations were conducted on growth level (physical development and Gesell scores) at 3, 6, 12 and 18 months.

RESULTS

The results of all the diagnostic tests performed in the patients of both groups all yielded a significantly higher abnormality rate in the aEEG abnormal group compared to the results in the aEEG normal group. Furthermore, the results of follow-up tests showing growth and child development also showed higher abnormality rates in the aEEG abnormal group than in the aEEG normal group.

CONCLUSIONS

Since the results of our aEEG monitoring were consistent with the findings of other diagnostic tests, we proved the convenience and effectivity of aEEG for guiding the treatment and prognosis of severe hyperbilirubinemia in neonates.

Brain magnetic resonance imaging and magnetic resonance spectroscopy findings of children with kernicterus

Background

The term kernicterus, or bilirubin encephalopathy, is used to describe pathological bilirubin staining of the basal ganglia, brain stem, and cerebellum, and is associated with hyperbilirubinemia. Kernicterus generally occurs in untreated hyperbilirubinemia or cases where treatment is delayed. Magnetic resonance imaging (MRI)-based studies have shown characteristic findings in kernicterus. The objective of our study was to describe the role of ¹H magnetic resonance spectroscopy (MRS) in demonstrating these metabolic changes and to review conventional MRI findings of kernicterus.

Material/Methods

Forty-eight pediatric cases with kernicterus were included in this study. MRI and MRS examinations were performed on variable dates (10–29 days after birth). NAA, Cr, Cho, NAA/Cr, NAA/Cho, and Cho/Cr values were evaluated visually and by computer analysis.

Results

There was no statistically significant difference between the NAA and Cho levels in the acute kernicterus patients and the control group (healthy patients), whereas both were significantly elevated in the chronic kernicterus patients. Both the mean NAA/Cr and Cho/Cr ratio values were significantly higher in the acute and chronic cases compared to the control group. The NAA/Cho ratio value was statistically lower in the acute cases than in the control group while it was similar in the chronic cases.

Conclusions

Conventional MR imaging and ¹H-MRS are important complementary tools in the diagnostics of neonatal bilirubin encephalopathy. This study provided important information for applying these MR modalities in the evaluation of neonates with bilirubin encephalopathy.

Magnetic resonance imaging of bilirubin encephalopathy: current limitations and future promise

Infants with chronic bilirubin encephalopathy often demonstrate abnormal bilateral, symmetric, high-signal intensity on T2-weighted magnetic resonance imaging of the globus pallidus and subthalamic nucleus, consistent with the neuropathology of kernicterus. Early magnetic resonance imaging of at-risk infants, while frequently showing increased T1-signal in these regions, may give false-positive findings due to the presence of myelin in these structures. Advanced magnetic resonance imaging including diffusion-weighted imaging, magnetic resonance spectroscopy, and diffusion tensor imaging with tractography may shed new insights into the pathogenesis of bilirubin-induced brain injury and the neural basis of long-term disability in infants and children with chronic bilirubin encephalopathy.