The role of apparent diffusion coefficient histogram metrics for differentiating pediatric medulloblastoma histological variants and molecular groups.

BACKGROUND: Medulloblastoma, a high-grade embryonal tumor, is the most common primary brain malignancy in the pediatric population. Molecular medulloblastoma groups have documented clinically and biologically relevant characteristics. Several authors have attempted to differentiate medulloblastoma molecular groups and histology variants using diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps. However, literature on the use of ADC histogram analysis in medulloblastomas is still scarce. OBJECTIVE: This study presents data from a sizable group of pediatric patients with medulloblastoma from a single institution to determine the performance of ADC histogram metrics for differentiating medulloblastoma variants and groups based on both histological and molecular features. MATERIALS AND METHODS: In this retrospective study, we evaluated the distribution of absolute and normalized ADC values of medulloblastomas. Tumors were manually segmented and diffusivity metrics calculated on a pixel-by-pixel basis. We calculated a variety of first-order histogram metrics from the ADC maps, including entropy, minimum, 10th percentile, 90th percentile, maximum, mean, median, skewness and kurtosis, to differentiate molecular and histological variants. ADC values of the tumors were also normalized to the bilateral cerebellar cortex and thalami. We used the Kruskal-Wallis and Mann-Whitney U tests to evaluate differences between the groups. We carried out receiver operating characteristic (ROC) curve analysis to evaluate the areas under the curves and to determine the cut-off values for differentiating tumor groups. RESULTS: We found 65 children with confirmed histopathological diagnosis of medulloblastoma. Mean age was 8.3 ± 5.8 years, and 60% (n = 39) were male. One child was excluded because histopathological variant could not be determined. In terms of medulloblastoma variants, tumors were classified as classic (n = 47), desmoplastic/nodular (n = 9), large/cell anaplastic (n = 6) or as having extensive nodularity (n = 2). Seven other children were excluded from the study because of incomplete imaging or equivocal molecular diagnosis. Regarding medulloblastoma molecular groups, there were: wingless (WNT) group (n = 7), sonic hedgehog (SHH) group (n = 14) and non-WNT/non-SHH (n = 36). Our results showed significant differences among the molecular groups in terms of the median (P = 0.002), mean (P = 0.003) and 90th percentile (P = 0.002) ADC histogram metrics. No significant differences among the various medulloblastoma histological variants were found. CONCLUSION: ADC histogram analysis can be implemented as a complementary tool in the preoperative evaluation of medulloblastoma in children. This technique can provide valuable information for differentiating among medulloblastoma molecular groups. ADC histogram metrics can help predict medulloblastoma molecular classification preoperatively.

Validation of Sonographic Fronto-Occipital Ratio Based on Anatomical Landmarks Compared to MR/CT-Derived Indexes in Children with Chiari II and Ventriculomegaly.

INTRODUCTION: Ultrasound (US)-based indexes such as fronto-occipital ratio (FOR) can be used to obtain an acceptable estimation of ventricular volume. Patients with colpocephaly present a unique challenge due to the shape of their ventricles. In the present study, we aimed to evaluate the validity and reproducibility of the modified US-FOR index in children with Chiari II-related ventriculomegaly. METHODS: In this retrospective study, we evaluated Chiari II patients younger than 1 year who underwent head US and MR or CT scans for ventriculomegaly evaluation. MR/CT-based FOR was measured in the axial plane by identifying the widest diameter of frontal horns, occipital horns, and the interparietal diameter (IPD). US-based FOR (US-FOR) was measured using the largest diameter based on the following landmarks: frontal horn and IPD in the coronal plane at the level of the foramen of Monro, IPD just superior to the Sylvian fissures, and occipital horn posterior to the thalami and inferior to the superior margins of the thalami. Intraclass correlation coefficients (ICCs) were used to evaluate inter-rater reliability, and Pearson correlation coefficients and Bland-Altman plots were applied to assess agreement between US and other two modalities. RESULTS: Sixty-three paired US and MR/CT exams were assessed for agreement between US-FOR and MR/CT-FOR measurements. ICC showed an excellent inter-rater reliability for US-FOR (ICC = 0.99, p < 0.001) and MR/CT-FOR (ICC = 0.99, p < 0.001) measurements. The mean (range) values based on US-FOR showed a slight overestimation in comparison with MR/CT-FOR (0.51 [0.36-0.68] vs. 0.46 [0.34-0.64]). The Pearson correlation coefficient showed high cross-modality agreement for the FOR index (r = 0.83, p < 0.001). The Bland-Altman plot showed excellent concordance between US-FOR and MR/CT-FOR with a bias of 0.05 (95% CI: -0.03 to 0.13). CONCLUSION: US-FOR in the coronal plane is a comparable tool for evaluating ventriculomegaly in Chiari II patients when compared with MR/CT-FOR, even in the context of colpocephaly.

Application of the Intracranial Arterial Pulsatility Index for Determination of Prognosis after Lacunar Infarct.

Background: We aimed to investigate the usefulness of intracranial arterial pulsatility index to assess the prognosis of lacunar infarcts. Materials and Methods: Forty-nine patients with confirmed acute lacunar infarct were enrolled in the study. A transcranial color-coded sonography was performed to assess the pulsatility index of bilateral middle cerebral, posterior cerebral, vertebral, and proximal internal carotid arteries. Patients' clinical status was assessed using a modified Rankin scale. Spearman correlation was used for reporting the relation between quantitative data. Statistical significance was defined as a two-tail p-value of less than 0.05. Results: The mean age ± standard deviation was 64.1 ± 9.07 years old, and 57.1% of the patients were male. Upon discharge, only 8.2% of the patients were ranked as 0 on the modified Rankin scale; however, after a 6-month follow-up period, this number increased to 49%. There were no significant differences between the left and right pulsatility index measurements in any of the assessed arteries. Patients with vertebral artery pulsatility indexes >1 on their primary assessment had significantly worse outcomes during the first, third, and sixth months follow-up (all r > 0.3, p-values < 0.01). Pulsatility indexes from other arteries did not predict the prognosis. Conclusion: Sonography-assisted assessment of the vertebral artery blood flow during the early stage of lacunar infarct provides a reliable reference for prognosis estimation.

Neuroimaging Findings in Parechovirus Encephalitis: A Case Series of Pediatric Patients.

BACKGROUND: Human parechovirus infection can cause parechovirus encephalitis in neonates and should be considered as a differential diagnosis in the emergency department. Neuroimaging features of parechovirus encephalitis have been described in neonates and young infants, but there is a paucity of literature regarding magnetic resonance imaging brain injury patterns in older children. We aim to present three cases of parechovirus encephalitis, showing distinctive magnetic resonance imaging brain patterns of injury in two newborns and, for the first time, in an adolescent. METHODS: We conducted a retrospective review of parechovirus encephalitis cases in our pediatric hospital. Clinical information and neuroimaging findings are described in detail. RESULTS: Classical neuroimaging findings in neonatal parechovirus encephalitis include restricted diffusion of the subcortical and periventricular white matter with frontoparietal predominance, in association with corpus callosum signal abnormality and bilateral swollen thalami. Parechovirus encephalitis in the adolescent appeared with an additional pattern of white matter signal abnormality in the corona radiata in continuity with the corticospinal tracts. CONCLUSIONS: Parechovirus encephalitis should be considered in the differential diagnosis when magnetic resonance imagingdemonstrates white matter injury with typical (sunburst type) distribution in the deep and periventricular white matter in both neonates and adolescents, especially in those with comorbidities or therapy that lead to an immunosuppressive status.

Mediastinal lymph node distribution, size and number: definitions based on an anatomical study.

OBJECTIVE: To create a reference map of mediastinal lymph nodes through the analysis of their size, number and distribution in various lymph node stations. METHOD: A total of 50 cadavers, 38 males and 12 females, were studied. Of those 50, 39 were Caucasian. The mean age was 59.9 +/= 14.1 years, the mean height was 173.1 +/= 7.6 cm, and the mean weight was 71.0 +/= 12.0 kg. A bilateral mediastinal dissection was performed in order to resect and isolate all lymph nodes. The area, as well as the major and minor transverse diameters, of each lymph node was determined by radiographic imaging analysis. RESULTS: In a sample of 485 chains, 1742 lymph nodes were dissected (2.58 +/= 1.89 lymph nodes/station), revealing a mean number of 21.2 +/= 8.5 lymph nodes on the right and 13.6 +/= 6.3 on the left. The lymph node stations 1, 2R, 4R, 5, and 7 were present in more than 90% of the sample. Only the 4R and 7 lymph node stations were always present. The lymph node stations 2L, 3p, and 8 were present in 32, 36, and 54% of the sample, respectively. Mediastinal lymph nodes were present in greater numbers in the 2R, 4R and 7 lymph node stations. In addition, these stations presented the largest mediastinal lymph nodes. CONCLUSION: Composing a reference map for lymph node sizes was feasible. No alterations were observed in the distribution, number, or size of lymph nodes in the age brackets studied, regardless of gender, race, weight, or height.

Tumores cutâneos raros em cabeça e pescoço: experiência de 4 anos em uma instituição terciária / Head and neck rare skin tumors: 4 years of experience in a tertiary institution

Introdução: O câncer de pele é o mais incidente dentre as neoplasias. Os tipos histológicos mais comuns são Carcinoma Basocelular (CBC), Carcinoma Espinocelular (CEC) e, menos frequente, o Melanoma. Geralmente acometem segmentos corporais expostos aos raios ultravioletas, principalmente a região de cabeça e pescoço. Porém, há outros tipos mais de tumores que acometem esta área e que fazem parte da prática da oncologia cutânea encaminhada aos cirurgiões de cabeça e pescoço. Objetivo: O objetivo deste trabalho é descrever estas neoplasias percutâneas raras que foram operadas no Instituto do Câncer do Estado de São Paulo (ICESP) nos últimos 4 anos. Resultados: As entidades Carcinoma de células de Merkel, Dermatofibrossarcoma protuberans, Angiossarcoma, Fibroxantoma atípico, Porocarcinoma, Carcinoma triquilemal, Carcinoma de células claras, Carcinoma sarcomatoide e Carcinoma apócrino compuseram 4,4% dos atendimentos de oncologia cutânea realizada pela Cirurgia de Cabeça e Pescoço. Uma breve revisão de cada entidade foi realizada. Discussão: A compreensão dos tipos histológicos raros é importante no tratamento de tumores cutâneos na prática da cirurgia de cabeça e pescoço.

Introduction: Skin cancer is the most frequent cancer among neoplasms. The most common histological types are Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC) and, less frequent, Melanoma. They generally affect body segments exposed to ultraviolet rays, especially the head and neck region. However, there are other types of tumors involving this area and they are part of the practice of cutaneous oncology referred to head and neck surgeons. Objective: The objective of this paper is to describe these rare cutaneous neoplasms, which were treated at the Instituto do Câncer do Estado de São Paulo (ICESP) in the last 4 years. Results: Merkel cell carcinoma, Dermatofibrosarcoma protuberans, Angiosarcoma, Atypical Fibroxanthoma, Porocarcinoma Trichilemmal carcinoma, Sarcomatoid carcinoma and Apocrine carcinoma comprised 4.4 % of cases of cutaneous oncology conducted by Head and Neck Surgery. A brief review of each neoplasm was performed. Discussion: understanding of the rare histological types is important in the treatment of skin tumors in the practice of head and neck surgery.

Distribuição, tamanho e número dos linfonodos mediastinais: definições por meio de estudo anatômico / Mediastinal lymph node distribution, size and number: definitions based on an anatomical study

OBJETIVO: Criar um mapa de referência dos linfonodos mediastinais através da análise de seu tamanho, número e distribuição nas diversas cadeias. MÉTODO: Um total de 50 cadáveres foram estudados, 38 do sexo masculino e 12 do feminino, sendo 39 brancos, com média de idade de 59,9 ± 14,1 anos, altura de 173,1 ± 7,6 cm e peso de 71,0 ± 12,0 kg. A dissecção do mediastino foi realizada bilateralmente, sendo todos os linfonodos ressecados e isolados. A área e os diâmetros transversos maior e menor de cada linfonodo foram determinados por análise de imagem. RESULTADOS: Em 485 cadeias, foram dissecados 1742 linfonodos (2,58 ± 1,89 linfonodos/cadeia). Observou-se uma média de 21,2 ± 8,5 linfonodos à direita e 13,6 ± 6,3 à esquerda. As cadeias 1, 2R, 4R, 5, e 7 estão presentes em mais de 90 por cento da amostra. Apenas as cadeias 4R e 7 estiveram sempre presentes. As cadeias 2L, 3p e 8 estiveram presentes em 32, 36 e 54 por cento, respectivamente. Os linfonodos mediastinais estão presentes em maior número nas cadeias 2R, 4R e 7. Estas mesmas cadeias também congregam os maiores linfonodos mediastinais. CONCLUSÃO: A composição de um mapa referencial para os tamanhos linfonodais foi factível. A distribuição, número e tamanho dos linfonodos não se alteraram no intervalo de idades estudado e não sofreram influência do sexo, raça, peso ou altura.

OBJECTIVE: To create a reference map of mediastinal lymph nodes through the analysis of their size, number and distribution in various lymph node stations. METHOD: A total of 50 cadavers, 38 males and 12 females, were studied. Of those 50, 39 were Caucasian. The mean age was 59.9 ± 14.1 years, the mean height was 173.1 ± 7.6 cm, and the mean weight was 71.0 ± 12.0 kg. A bilateral mediastinal dissection was performed in order to resect and isolate all lymph nodes. The area, as well as the major and minor transverse diameters, of each lymph node was determined by radiographic imaging analysis. RESULTS: In a sample of 485 chains, 1742 lymph nodes were dissected (2.58 ± 1.89 lymph nodes/station), revealing a mean number of 21.2 ± 8.5 lymph nodes on the right and 13.6 ± 6.3 on the left. The lymph node stations 1, 2R, 4R, 5, and 7 were present in more than 90 percent of the sample. Only the 4R and 7 lymph node stations were always present. The lymph node stations 2L, 3p, and 8 were present in 32, 36, and 54 percent of the sample, respectively. Mediastinal lymph nodes were present in greater numbers in the 2R, 4R and 7 lymph node stations. In addition, these stations presented the largest mediastinal lymph nodes. CONCLUSION: Composing a reference map for lymph node sizes was feasible. No alterations were observed in the distribution, number, or size of lymph nodes in the age brackets studied, regardless of gender, race, weight, or height.