Direct comparison between apparent diffusion coefficient and macromolecular proton fraction as quantitative biomarkers of the human fetal brain maturation.

BACKGROUND: Apparent diffusion coefficient (ADC) is known as a quantitative biomarker of prenatal brain maturation. Fast macromolecular proton fraction (MPF) mapping is an emerging method for quantitative assessment of myelination that was recently adapted to fetal MRI. PURPOSE: To compare the capability of ADC and MPF to quantify the normal fetal brain development. STUDY TYPE: Prospective. POPULATION: Forty-two human fetuses in utero (gestational age [GA] = 27.7 ± 6.0, range 20-38 weeks). FIELD STRENGTH/SEQUENCE: 1.5 T; diffusion-weighted single-shot echo-planar spin-echo with five b-values for ADC mapping; spoiled multishot echo-planar gradient-echo with T1 , proton density, and magnetization transfer contrast weightings for single-point MPF mapping. ASSESSMENT: Two operators measured ADC and MPF in the medulla, pons, cerebellum, thalamus, and frontal, occipital, and temporal cerebral white matter (WM). STATISTICAL TESTS: Mixed repeated-measures analysis of variance (ANOVA) with the factors of pregnancy trimester and brain structure; Pearson correlation coefficient (r); Hotelling-Williams test to compare strengths of correlations. RESULTS: From the 2nd to 3rd trimester, ADC significantly decreased in the thalamus and cerebellum (P < 0.005). MPF significantly increased in the medulla, pons, thalamus, and cerebellum (P < 0.005). Cerebral WM had significantly higher ADC and lower MPF compared with the medulla and pons in both trimesters. MPF (r range 0.83, 0.89, P < 0.001) and ADC (r range -0.43, -0.75, P ≤ 0.004) significantly correlated with GA and each other (r range -0.32, -0.60, P ≤ 0.04) in the medulla, pons, thalamus, and cerebellum. No significant correlations or distinctions between regions and trimesters were observed for cerebral WM (P range 0.1-0.75). Correlations with GA were significantly stronger for MPF compared with ADC in the medulla, pons, and cerebellum (Hotelling-Williams test, P < 0.003) and similar in the thalamus. Structure-averaged MPF and ADC values strongly correlated (r = 0.95, P < 0.001). DATA CONCLUSION: MPF and ADC demonstrated qualitatively similar but quantitatively different spatiotemporal patterns. MPF appeared more sensitive to changes in the brain structures with prenatal onset of myelination. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;50:52-61.

CLIPPERS: Multiparametric and quantitative MRI features.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare chronic central-nervous-system inflammatory disorder that became known only recently, and the pathogenesis of CLIPPERS remains poorly understood. This report presents clinical and radiological features of a rare case: a young female patient who rapidly died of suspected CLIPPERS. Helpful multiparametric MRI diagnostic criteria are proposed that can help discriminate CLIPPERS from non-CLIPPERS pathologies. We reviewed clinical history, symptoms, quantitative data from brain multiparametric MRI before and after treatment, and histopathological data. Perfusion-weighted imaging revealed a decrease in regional cerebral blood flow by 31% and in cerebral blood volume by 64%, with a moderate increase in transit time and in time to peak by up to 23% in affected pontine and cerebral white matter. As estimated by diffusion tensor imaging, there was elevated density of tracts (n/mm2) and a decrease of fraction anisotropy (×10-3 mm/s2) in the patient's pons as compared to a healthy control: density of tracts = 13.5 vs 12.4 and fraction anisotropy = 0.32 vs 0.45, respectively. Macromolecular proton fraction values proved to be reduced (15.8% and 14.5% in the control, respectively) in the patient's cerebral peduncles by 3% and in the pons by 4.1% and in a periventricular white matter lesion by 6.4% (11.3% in the normal-looking contralateral hemisphere). Based on our findings, we argue that quantitative MRI techniques may be a valuable source of biomarkers and reliable diagnostic criteria and can shed light on the pathogenesis and exact nosological position of this disorder.

Corrigendum to "CLIPPERS: Multiparametric and quantitative MRI features" [Radiology Case Reports 18 (2023) 368-376].

[This corrects the article DOI: 10.1016/j.radcr.2022.10.043.].

Huge cerebral pial arteriovenous fistula in a newborn: illustrative case.

BACKGROUND: Pediatric arteriovenous malformations (AVMs) and pial/dural arteriovenous fistulas (AVFs) are rare but life-threatening complications that can lead to congestive heart failure and hemorrhagic stroke in newborns and pediatric patients. The pronounced shunting in these conditions is associated with early complications and necessitates aggressive surgical management. Here, the authors describe endovascular treatment of an atypical cerebral pial AVF in a newborn. OBSERVATIONS: This AVF formed direct communication between a major cerebral artery (basilar artery) and a large draining vein (dilated deep cerebral vein). The authors performed earlier subtotal embolization of the AVF using 0.020-inch coils, which led to progressive thrombosis of the fistula with restoration of normal arterial blood flow. The patient was discharged 18 days after surgery, examination at 1.5 and 6 months showed magnetic resonance imaging signs of blood flow absence through the fistula and satisfactory condition of the infant without physical and mental developmental delay. LESSONS: Subtotal coiling of a high-flow pial AVF in a newborn can result in a good clinical outcome.

Iniencephaly: radiologic and pathomorphologic perinatal observation.

Iniencephaly (IE) is a rare neural tube malformation involving severe head retroflexion and deformity of the spine. IE is typically accompanied with other congenital abnormalities and carrying a poor fetal prognosis. This report presents radiological findings in a rare case of IE associated with multiple malformations of the skull, spine, face, heart, and body. A 44-year-old pregnant female underwent an obstetric ultrasound examination on the 26th week of gestation followed by fetal magnetic resonance imaging on the 36th week. Imaging revealed complex developmental anomalies, which led to the diagnosis of IE with a large cervical meningocele, occipital bone defect, spina bifida of the cervical vertebrae, multiple malformed vertebra, deformed face, coarctation of the aortic arch, and hypoplastic lungs. Based on these findings, a decision to terminate pregnancy was made. Pathological examination of the fetus showed close agreement with imaging. The presented case underscores the importance of multimodal imaging for clinical decision making in the management of complex neural tube malformations.

Congenital medulloblastoma: Fetal and postnatal longitudinal observation with quantitative MRI.

Congenital medulloblastoma is extremely rare. MRI appearance of this tumor in the fetal brain has not been described. A case of congenital medulloblastoma initially observed by antenatal MRI with postnatal follow-up and treatment is presented. A pregnant female underwent fetal MRI on the 31st gestational week for routine indications. Midline cerebellar lesion of ≤2 cm in size with minor T2 hypointensity and T1 hyperintensity was identified. Additionally, quantitative MRI including apparent diffusion coefficient (ADC) and fast macromolecular proton fraction (MPF) mapping was performed. The lesion showed a marked ADC decrease and MPF increase. MPF maps depicted the lesion most conspicuously. After term delivery, a male neonate presented with symptoms of increased intracranial pressure. Postnatal MRI identified obstructive hydrocephalus caused by a large posterior fossa mass. The child was treated by cerebrospinal fluid shunt placement. Follow-up quantitative MRI on the fifth month revealed tumor growth and vivid changes of its tissue contrast associated with brain maturation. The tumor appeared nearly isointense on T1- and T2-weighted images and slightly hypointense on the ADC map. MPF contrast showed the most remarkable change from hyper- to hypointensity due to brain myelination with stable MPF in the tumor. Subsequently, the child underwent partial tumor resection, and currently continues treatment with chemotherapy. The pathological diagnosis was desmoplastic/nodular medulloblastoma. The described case illustrates evolution of the tumor contrast in the course of fetal and postnatal brain development and highlights the added diagnostic value of MPF mapping in fetal and neonatal neuroimaging.