Filippo Arrigoni

Introduction: Lumbar spondylolysis is a common cause of low back pain in adolescents, yet early and confident diagnosis often requires CT, exposing patients to radiation. The Black-Bone (BB) MR sequence is a 3D low–flip-angle gradient-echo (GRE) acquisition designed to enhance bone–soft tissue contrast. This study assessed whether adding BB to a standard pediatric lumbar MRI protocol improves diagnostic accuracy, interreader-agreement, and confidence. Methods: Forty-four adolescents (mean age, 12 years; 23 girls, 21 boys) with suspected spondylolysis underwent lumbar MRI including BB, with radiographs and/or CT as reference standard. Thirty patients had confirmed spondylolysis and 14 served as controls. Four blinded readers (2 senior neuroradiologists, 2 residents) independently reviewed all cases twice: first with standard MRI only, then with BB included. Readers scored each pars interarticularis level and side (0 = negative, 1 = probable, 2 = definite). Interrater agreement (weighted Cohen’s κ), sensitivity, specificity, PPV, NPV, and accuracy were calculated. Results: BB improved interrater agreement across all pairs (κ 0.81–0.93 vs. 0.59–0.82 pre-BB). Sensitivity increased for all readers (+ 5–12% points), while specificity remained high (0.89–1.00). PPV was consistently excellent (0.93–1.00), and NPV improved with BB (0.83–0.87 vs. 0.75–0.83 pre-BB). Ambiguous ratings dropped from 58 pre-BB to 5 post-BB, resolving > 90% of indeterminate assessments. Accuracy increased by approximately 2–5% points, whereas diagnostic confidence showed a larger improvement. Conclusion: Incorporating BB into pediatric lumbar MRI protocols improved interreader agreement and diagnostic confidence while markedly reducing equivocal interpretations. Although diagnostic performance metrics improved, these findings should be interpreted cautiously given the limited CT correlation. BB may represent a practical radiation-free adjunct to standard MRI for evaluating suspected pediatric spondylolysis.

Background: Polymicrogyria is a heterogeneous cortical malformation resulting from disruption of multiple processes of cortical development, either genetically determined or acquired. Objective: To characterize early imaging and histopathological features of incipient polymicrogyria in fetuses at early gestational age and correlate radiological patterns with underlying etiopathogenic mechanisms. Materials and methods: Four fetuses at 21 weeks’ gestational age with suspected polymicrogyria on fetal magnetic resonance imaging underwent post-mortem magnetic resonance imaging (PMMRI) and detailed neuropathological examination, including immunohistochemistry (NeuN, NSE, GFAP, MBP, CD3, CD68). Imaging and histological findings were systematically compared. Results: Distinct imaging–histopathological patterns were identified according to etiology (ischemic, infectious, genetic). Key differentiating features included symmetry of involvement, cerebral surface appearance, integrity of the pial basement membrane, laminar pattern alterations, and associated anomalies. Conclusion: Combined PMMRI and neuropathology enable early characterization of polymicrogyria and provide insights into its etiopathogenesis, improving differential diagnosis and genetic counseling.

This article reviews the key concepts in pediatric headaches and provides a guide for neuroimaging assessment of children (≥ 2 years) and adole

Background: Quantitative susceptibility mapping (QSM) is an advanced magnetic resonance imaging (MRI) technique that quantifies tissue magnetic susceptibility, offering non-invasive insights into brain microstructure, including iron content and myelination. While extensively applied in adult neuroimaging, its use in pediatric populations is rapidly expanding. Purpose: This systematic review aims to provide a comprehensive overview of QSM applications in pediatric brain imaging, highlighting methodological advancements, diagnostic potential, and current limitations. Methods: A systematic literature search was performed using PubMed and Google Scholar up to April 2025. Inclusion criteria were original research articles written in English, involving only pediatric populations (0–17 years) and employing QSM in brain imaging. Twenty studies met eligibility criteria and were analyzed in terms of acquisition protocols, post-processing methods, study objectives, and main findings. Results: A systematic search on PubMed and Google Scholar found 54 QSM brain studies in children; after exclusions, 20 original research papers qualified for review and were quality-checked using Quality Assessment of Diagnostic Accuracy Studies version-2 (QUADAS-2). Most studies were recent (85% in the last 5 years), in Asia (55%, with China 35%), and used 3-tesla (T) MRI (80%). Typical imaging parameters: 8 echoes (TE=40 ms), slice thickness=2–2.5 mm, matrix often 256×256; Laplacian was the main phase-unwrapping method and variable-kernel sophisticated harmonic artifact reduction for phase data (VSHARP) the dominant background-field removal. Study aims clustered into improved detection, microstructural analysis, normative comparisons, clinical correlations, developmental patterns, and pathology tracking. Conclusion: QSM emerges as a valuable tool in pediatric neuroimaging, offering quantitative biomarkers for brain development, disease monitoring, and potential clinical translation. Despite promising results, challenges remain, including motion artifacts, lack of normative pediatric data, and methodological heterogeneity. Future research should focus on longitudinal designs, standardization of protocols, and integration with complementary imaging modalities. With further refinement, QSM has the potential to become an integral component of pediatric neuroradiological assessment.

Using a machine learning approach, three distinct structural MRI–based biological subtypes of Friedreich ataxia were identified, with different patterns of brain degeneration and associations with clinical severity.

Introduction: Ventriculomegaly (VM) is the fetal central nervous system (CNS) anomaly most commonly represented in prenatal imaging. It is defined as a lateral ventricle of dimensions greater than or equal to 10 mm; it can be unilateral or bilateral. More generally, hydrocephalus is defined as an imbalance between brain parenchyma and cerebrospinal fluid (CSF) due to an abnormal increase of the latter within the ventricles in an almost bilateral manner. To identify ventriculomegaly and categorize its severity, the appropriate imaging and measurement methods are crucial. Clinical outcomes vary greatly because of the wide differential diagnosis. Furthermore, there is a significant chance that these causes may recur in subsequent pregnancies. Pregnancy care and counseling depend on a precise diagnosis of the underlying cause. Materials and methods: We retrospectively reviewed our institutional fetal MR imaging database (4568 examinations) from 2005 until 2024. We focused on obstructive hydrocephalus and, according to rigorous inclusion/exclusion criteria (Table 1), we enrolled 201 cases. Results: We analyzed isolated aqueduct stenosis (36.3%); hemorrhagic events (30.3%); rhombencephalosynapsis (7.5%); dural sinus malformation (6%); midline cysts (5.4%); diencephalic-mesencephalic junction (DMJ) dysplasia (3.5%); infectious lesions (3%); tumors (2.5%); Chiari 1 (1.5%); Walker Warburg disease (1%); not otherwise specified (3%). Discussion: We discuss the different etiologies of obstructive hydrocephalus in our population and propose an etiology-based approach that allows the clinician and radiologist to reach the correct differential diagnosis and provide an indication for possible fetal surgery. Conclusion: Hydrocephalus arises from embryological abnormalities or acquired insults, requiring precise neuroimaging for diagnosis and management. A thorough imaging approach aids in etiological diagnosis, surgical planning, and essential counseling.

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder, caused by mutations in the ABCD1 gene. Early diagnosis is critical to manage adrenal insufficiency and cerebral forms of the disease. Since 2021, a pilot newborn screening (NBS) program for X-ALD has been launched in Lombardy, Italy. From September 2021 to June 2025, 138,116 newborns (≥37 weeks’ gestational age) were screened for elevated C26:0-lysophosphatidylcholine (C26:0-LPC) levels using a two-tier algorithm. Genetic testing was performed in non-negative cases. Males found to be ABCD1 variant carriers were enrolled in multidisciplinary follow-up, including neurological, endocrinological, and nutritional assessments. Eleven individuals (six males, five females) carried pathogenic or likely pathogenic ABCD1 variants. Three males were diagnosed with adrenal insufficiency and started hydrocortisone therapy between 1 and 2 years of age. Growth parameters were within normal range overall, but two children showed signs of stunting associated with poor dietary compliance. Additionally, three patients were diagnosed with Zellweger spectrum disorders (ZSDs). No patients affected with Aicardi-Goutières Syndrome were identified. Newborn screening for X-ALD in Italy is feasible and enables early detection and intervention. Biochemical markers and genetic analysis are reliable tools for identifying affected males and female carriers. Multidisciplinary management is essential to address medical and psychosocial challenges during follow-up.

SUMMARY: Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is an uncommon condition represented by an infantile-onset disorder, frequently arising from heterozygous mutations in the SLC2A1 gene. Individuals with GLUT1-DS may present with early-onset seizures (typically manifesting before 4 years of age), developmental delay, and complex movement disorders. In fewer cases, stroke-like events or hemiplegic migraine-like symptoms are also reported, defined by unilateral paresis affecting 1 side of the body and/or one-half of the face, occasionally accompanied by speech impairment. Currently, the pathomechanism underlying these acute transient clinical manifestations is poorly understood. MR imaging studies performed in the absence of acute manifestations frequently reveal nonspecific imaging signs associated with this syndrome. We present findings obtained using the arterial spin-labeling technique for perfusion imaging and MRA during the acute onset of stroke-like episodes in a series of 4 pediatric patients with GLUT1-DS. We observed reversible hypoperfusion in the left hemisphere and associated reversible attenuation of distal MCA branches on MRA. A notable association between unilateral cerebral hypoperfusion and transient crossed cerebellar diaschisis was evident on perfusion maps as well.

Background and purpose: Cerebellar heterotopia (CH) is a neuroradiological abnormality poorly reported and investigated in the literature. It can be observed as an isolated finding, but it has been mainly reported in the context of cerebellar dysgenesis and in syndromic conditions. The aim of this study is to provide a comprehensive neuroradiological, clinical, and genetic characterization of a cohort of pediatric patients with cerebellar heterotopia. Materials and methods: Patients with a diagnosis of CH were systematically selected from the neuroimaging databases of the four Italian Centers participating in this retrospective study. For each patient, information regarding demographic, clinical, genetic and neuroradiological data were collected. Results: Thirty-two pediatric patients were recruited and subdivided into two groups: patients with isolated CH and/or cerebellar malformations (n= 18) and patients with CH associated with cerebral malformations (n=14). Isolated CH consistently showed a peripheral subcortical localization in the inferior portion of cerebellar hemispheres, with either unilateral or bilateral distribution. Ten patients belonging to the second group had a diagnosis of CHARGE syndrome, and their nodules of CH were mainly but not exclusively bilateral, symmetric, located in the peripheral subcortical zone and in the inferior portion of the cerebellar hemispheres; the remaining 4 patients of the second group, showed either bilateral or unilateral CH, located in both peripheral cortex and deep white matter and in the superior and inferior portions of cerebellum. Patients with isolated CH showed high prevalence of language development delay; neurodevelopmental disorders were the most represented clinical diagnoses. Recurring features were behavioral problems and motor difficulties. A conclusive genetic diagnosis was found in 18/32 patients. Conclusions: We found distinctive neuroradiological patterns of CH. Genetic results raise the possibility of a correlation between cerebellar morphological and functional developmental disruption, underscoring the importance of CH detection and reporting to orient the diagnostic path. Abbreviations CH Cerebellar heterotopia; MRI Magnetic resonance imaging; CC Corpus callosum; ASD autism spectrum disorder; IVH inferior vermian hypoplasia.