Imaging in neuroblastoma

Neuroblastoma is the most common extracranial solid malignancy of childhood. The prognosis is highly variable ranging from spontaneous involution in infants to fatal outcome, despite aggressive treatment, in disseminated high-risk neuroblastoma. This paper provides a comprehensive review of the crucial role of imaging during the extensive treatment course

Abdominal lymph node size in children at computed tomography

Background: Lymph node enlargement is commonly used to indicate abnormality. Objective: To evaluate the normal size and prevalence of abdominal lymph nodes in children at CT. Materials and methods: In this retrospective study, we included a total of 152 children ages 1–17 years who underwent abdominal CT examination after high-energy trauma. We measured abdominal lymph nodes in five lymph node stations (inguinal, iliac, para-aortic, hepatic and mesenteric). For the largest lymph node in each level, we measured long- and short-axis diameters in both the axial and coronal planes. We then calculated distribution parameters, correlation coefficients between lymph node size and age, and reference intervals. Results: The prevalence of detectable lymph nodes was high for the inguinal (100%), iliac (98%), para-aortic (97%) and mesenteric (99%) stations and lower for the hepatic station (32%). Lymph node size showed small to medium significant correlations (ranging from 0.21 to 0.50) with age. When applying the Lugano criteria and RECIST (Response Criteria in Solid Tumors), 29 children (19%) would have had one or more enlarged abdominal lymph nodes. Conclusion: The results of this study provide normative data of abdominal lymph node size in children. The current adult guidelines for enlarged lymph nodes seem adequate for most children with the exception of young adolescents, in which larger lymph nodes were relatively common, particularly in the inguinal region

A meta-analysis on the diagnostic performance of whole-body MRI for the initial staging of Hodgkin lymphoma in children and adults using FDG-PET/CT as a reference standard

Background: Staging of Hodgkin lymphoma is important for determining prognosis and treatment planning. The current gold standard is FDG-PET/CT, but WB-MRI could be a radiation free alternative. Objective: A meta-analysis of all published data on the diagnostic performance of WB-MRI for the initial staging of Hodgkin lymphoma using FDG-PET/CT as a reference standard. Evidence Acquisition: Both the PubMed/MEDLINE and EMBASE databases were systematically searched (updated until March 14, 2023) for studies that compared WB-MRI with FDG-PET/CT for staging Hodgkin lymphoma. The “quality assessment of diagnostic accuracy studies” tool (QUADAS-2) was used to assess methodological quality. Pooled staging accuracy, sensitivity and specificity of WB-MRI compared to FDG-PET/CT was calculated for determining stage and for both nodal and extra-nodal staging. A sensitivity analysis for children and adults was performed. Evidence Synthesis: A total of nine studies with a combined total of 297 Hodgkin lymphoma patients were included. Pooled sensitivity and specificity for nodal staging were 94% (95%CI 0.92–0.96) and 99% (95%CI 0.98–1.00) respectively. For extra-nodal staging sensitivity and specificity were 90% (95%CI 0.74–0.96) and 100% (95%CI 0.99–1.00). For disease stage, the pooled accuracy was 92% for pediatric studies (95%CI 0.86–0.96), 94% for adult studies (95%CI 0.87–0.97) and 92% (95%CI 0.87–0.96) for all studies combined. Conclusion: When using FDG-PET/CT as a reference standard, WB-MRI shows high sensitivity and specificity for both nodal and extra-nodal staging and for determining disease stage both in children and adults. Clinical Impact: WB-MRI could be used as a good radiation-free alternative for FDG-PET/CT in Hodgkin lymphoma staging

Frequency and characteristics of pulmonary nodules in children at computed tomography

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MRI Characteristics of Pediatric and Young-Adult Renal Cell Carcinoma: A Single-Center Retrospective Study and Literature Review

Pediatric renal cell carcinoma (RCC) is a rare malignancy. Magnetic resonance imaging (MRI) is the preferred imaging modality for assessment of these tumors. The previous literature has suggested that cross-sectional-imaging findings differ between RCC and other pediatric renal tumors and between RCC subtypes. However, studies focusing on MRI characteristics are limited. Therefore, this study aims to identify MRI characteristics of pediatric and young-adult RCC, through a single-center case series and literature review. Six identified diagnostic MRI scans were retrospectively assessed, and an extensive literature review was conducted. The included patients had a median age of 12 years (63–193 months). Among other subtypes, 2/6 (33%) were translocation-type RCC (MiT-RCC) and 2/6 (33%) were clear-cell RCC. Median tumor volume was 393 cm3 (29–2191 cm3). Five tumors had a hypo-intense appearance on T2-weighted imaging, whereas 4/6 were iso-intense on T1-weighted imaging. Four/six tumors showed well-defined margins. The median apparent diffusion coefficient (ADC) values ranged from 0.70 to 1.20 × 10−3 mm2/s. In thirteen identified articles focusing on MRI characteristics of MiT-RCC, the majority of the patients also showed T2-weighted hypo-intensity. T1-weighted hyper-intensity, irregular growth pattern and limited diffusion–restriction were also often described. Discrimination of RCC subtypes and differentiation from other pediatric renal tumors based on MRI remains difficult. Nevertheless, T2-weighted hypo-intensity of the tumor seems a potential distinctive characteristic

Whole-body MRI versus an [F-18]FDG-PET/CT-based reference standard for early response assessment and restaging of paediatric Hodgkin's lymphoma:a prospective multicentre study

Objectives To compare WB-MRI with an [F-18]FDG-PET/CT-based reference for early response assessment and restaging in children with Hodgkin's lymphoma (HL). Methods Fifty-one children (ages 10-17) with HL were included in this prospective, multicentre study. All participants underwent WB-MRI and [F-18]FDG-PET/CT at early response assessment. Thirteen of the 51 patients also underwent both WB-MRI and [F-18]FDG-PET/CT at restaging. Two radiologists independently evaluated all WB-MR images in two separate readings: without and with DWI. The [F-18]FDG-PET/CT examinations were evaluated by a nuclear medicine physician. An expert panel assessed all discrepancies between WB-MRI and [F-18]FDG-PET/CT to derive the [F-18]FDG-PET/CT-based reference standard. Inter-observer agreement for WB-MRI was calculated using kappa statistics. Concordance, PPV, NPV, sensitivity and specificity for a correct assessment of the response between WB-MRI and the reference standard were calculated for both nodal and extra-nodal disease presence and total response evaluation. Results Inter-observer agreement of WB-MRI including DWI between both readers was moderate (kappa 0.46-0.60). For early response assessment, WB-MRI DWI agreed with the reference standard in 33/51 patients (65%, 95% CI 51-77%) versus 15/51 (29%, 95% CI 19-43%) for WB-MRI without DWI. For restaging, WB-MRI including DWI agreed with the reference standard in 9/13 patients (69%, 95% CI 42-87%) versus 5/13 patients (38%, 95% CI 18-64%) for WB-MRI without DWI. Conclusions The addition of DWI to the WB-MRI protocol in early response assessment and restaging of paediatric HL improved agreement with the [F-18]FDG-PET/CT-based reference standard. However, WB-MRI remained discordant in 30% of the patients compared to standard imaging for assessing residual disease presence

Surgical challenges of excision of retroperitoneal germ cell tumors in children: a single institutional study with literature review

Background: Retroperitoneal germ cell tumors (GCTs) are rare, commonly large tumors, often diagnosed in infancy. Complete surgical resection may pose a serious challenge as encasement of major vessels and organ displacement can lead to perioperative complications. This study aims to illustrate the surgical challenges of excising retroperitoneal GCTs. Results: Nine patients were included: six patients with a teratoma, two patients with a mixed GCT with a yolk sac tumor component, and one patient with a pure yolk sac tumor. Six were males and seven were younger than 1 year of age at time of presentation. In all cases, perioperative vascular or organ-related complications occurred in one patient; this resulted in short bowel syndrome. There was no recurrence or mortality during the follow-up period. Relevant literature is reviewed and described. Conclusions: The anatomical relation of a retroperitoneal GCT to the major vessels and organs is unpredictable. Preoperative radiological evaluation can help to improve the understanding of the vascular anatomy and to plan accordingly. Anteriorly displaced veins may appear insignificant and arteries, such as the superior mesenteric artery may be encased. Preoperative imaging may prevent perioperative complications, leading to safer surgical procedures. Level IV evidence: Therapeutic stud

The diagnostic value of magnetic resonance imaging in differentiating benign and malignant pediatric ovarian tumors

BACKGROUND: The diagnostic workup of ovarian tumors in children and adolescents is challenging because preserving fertility, in addition to oncological safety, is of particular importance in this population. Therefore, a thorough preoperative assessment of ovarian tumors is required. OBJECTIVE: To investigate the diagnostic value of MR imaging in differentiating benign from malignant ovarian tumors in children and adolescents. MATERIALS AND METHODS: We conducted a retrospective study of all children and adolescents age <18 years who underwent MR imaging of ovarian tumors during 2014-2019 at a pediatric specialty center. Two radiologists reviewed all MR imaging. We used pathology reports to define the histological diagnosis. RESULTS: We included 30 girls who underwent MR imaging for an ovarian tumor. Signs indicative for malignancy were tumors with a diameter ≥8 cm, with areas of contrast enhancement, irregular margins, extracapsular tumor growth, and ascites. All benign and malignant ovarian tumors were correctly identified by the radiologists. CONCLUSION: The diagnostic utility of MR imaging in classifying ovarian tumors in children and adolescents as benign or malignant is promising and might aid in defining the indication for ovarian-sparing versus non-ovarian-sparing surgery. We recommend evaluating these tumors with MR imaging prior to deciding on surgical treatment

The contribution of surgical clips for optimizing highly-conformal image-guided flank irradiation in pediatric renal tumors: a single center experience

Background and aims: Two-opposing photon beams are considered standard of care for flank irradiation in pediatric patients with renal tumors. Nowadays, Image-Guided Radiotherapy (IGRT) techniques allow high-precision dose delivery to complex flank target volumes taking into account postoperative organ shifts and tumor bed motion. This study examines the contribution of a lateral and superior surgical clip on flank target volume delineation intended for IGRT. Methods: Between 01-2015 and 09-2019, 30/162 newly-diagnosed pediatric patients with renal tumors, lateral/superior surgical clips (n = 30/30) and available 4D-CT-scans (n = 27/30), underwent postoperative flank irradiation. The lateral and superior clip, as respective markers for the lateral tumor extension and intrafraction motion, were analyzed. The positive and negative values depict the lateral/dorsal/cranial or the medial/ventral/caudal direction, respectively. Planning target volumes (PTV) were generated based on lateral clips (PTV latclip), superior clips with 4D-CT technology (PTV supclip), and both clips combined (PTV combined), and compared to an approach without clips (PTV noclip). Results: Indicated by clips, the mean lateral tumor bed extension along the posterior wall was 74° (range: 50°–93°), while mean intrafraction motion was +1.2 mm (range: −1.8/+4.8 mm), +0.6 mm (range: +0.6/+4.9 mm), −0.3 mm (range: −3.8/+0.7 mm) in craniocaudal, ventrodorsal, mediolateral direction, respectively. The median PTV noclip (556 mL) was statistically different from the median PTV latclip (454 mL, p = <0.01), median PTV supclip (373 mL, p = <0.01) and median PTV combined (348 mL p = <0.01). Conclusion: In pediatric patients with renal tumors, surgical clips at the lateral and superior border of the tumor bed can optimize flank target volume delineation and, consequently, reduce the normal tissue volume receiving high-dose irradiation when IGRT techniques are applied

Testis Sparing Surgery in Pediatric Testicular Tumors

OBJECTIVE: The purpose of this review is to evaluate the outcomes of testis sparing surgery (TSS) and to investigate under which circumstances TSS can be considered a safe treatment option in pediatric patients with testicular tumors. METHODS: A database search was performed in Cochrane, Pubmed, and Embase for studies that focused on TSS as treatment for testicular tumors in the pediatric population, excluding reviews and single case reports. RESULTS: Twenty studies, describing the surgical treatment of 777 patients with testicular tumors, were included in the analysis. The majority of pediatric patients with benign germ cell tumors (GCTs) (mean age: 3.7 years) and sex cord-stromal tumors (SCSTs) (mean age: 6.6 years) were treated with TSS, 61.9% and 61.2%, respectively. No cases of testicular atrophy occurred. Four of the benign GCTs, i.e., three teratomas and one epidermoid cyst, recurred. No cases of recurrence were reported in patients with SCSTs. Of the 243 malignant GCTs (mean age: 4.2 years), only one patient had TSS (0.4%). CONCLUSION: TSS is a safe treatment option for prepubertal patients less than 12 years of age with benign GCTs and low grade SCSTs