Frequency and characteristics of pulmonary nodules in children at computed tomography

Detail viewDemolished ; site on Q Street where Embassy Suites now stand

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

Whole-body MRI versus an FDG-PET/CT-based reference standard for staging of paediatric Hodgkin lymphoma:a prospective multicentre study

Objectives To assess the concordance of whole-body MRI (WB-MRI) and an FDG-PET/CT-based reference standard for the initial staging in children with Hodgkin lymphoma (HL) Methods Children with newly diagnosed HL were included in this prospective, multicentre, international study and underwent WB-MRI and FDG-PET/CT at staging. Two radiologists and a nuclear medicine physician independently evaluated all images. Discrepancies between WB-MRI and FDG-PET/CT were assessed by an expert panel. All FDG-PET/CT errors were corrected to derive the FDG-PET/CT-based reference standard. The expert panel corrected all reader errors in the WB-MRI DWI dataset to form the intrinsic MRI data. Inter-observer agreement for WB-MRI DWI was calculated using overall agreement, specific agreements and kappa statistics. Concordance for correct classification of all disease sites and disease stage between WB-MRI (without DWI, with DWI and intrinsic WB-MRI DWI) and the reference standard was calculated as primary outcome. Secondary outcomes included positive predictive value, negative predictive value and kappa statistics. Clustering within patients was accounted for using a mixed-effect logistic regression model with random intercepts and a multilevel kappa analysis. Results Sixty-eight children were included. Inter-observer agreement between WB-MRI DWI readers was good for disease stage (kappa= 0.74). WB-MRI DWI agreed with the FDG-PET/CT-based reference standard for determining disease stage in 96% of the patients versus 88% for WB-MRI without DWI. Agreement between WB-MRI DWI and the reference standard was excellent for both nodal (98%) and extra-nodal (100%) staging. Conclusions WB-MRI DWI showed excellent agreement with the FDG-PET/CT-based reference standard. The addition of DWI to the WB-MRI protocol improved the staging agreement

Whole-Body MRI in Pediatric Oncology

Whole-body imaging plays a crucial role in the diagnosis and follow-up of pediatric malignancies, as tumor spread may involve different anatomical regions. Until recently, ultrasonography (US) and computed tomography (CT) have been the imaging technique of choice in children with cancer, but nowadays there is an increasing interest in the use of functional imaging techniques like single-photon emission computed tomography (SPECT) and positron emission tomography (PET). By combining these latter techniques with CT, it becomes possible to simultaneously acquire imaging data on the biological behavior of tumor as well as the anatomical localization and extent of tumor spread. Because of the small but not negligible risk of radiation-induced secondary cancers and the significantly improved overall survival rates of children with cancer, there is an increasing interest in the use of radiation-free imaging techniques such as magnetic resonance imaging (MRI). MRI allows for acquiring images with a high spatial resolution and excellent soft tissue contrast throughout the body. Moreover, recent technological advances have resulted in fast diagnostic sequences for whole-body MR imaging, including functional techniques such as diffusion-weighted imaging (DWI). In this chapter, the current status of the technique, major clinical applications, and future perspectives of whole-body MRI in children with cancer will be discussed

Whole-body MRI in paediatric oncology

Imaging plays a crucial role in the diagnosis and follow-up of paediatric malignancies. Until recently, computed tomography (CT) has been the imaging technique of choice in children with cancer, but nowadays there is an increasing interest in the use of functional imaging techniques like positron emission tomography and single-photon emission tomography. These later techniques are often combined with CT allowing for simultaneous acquisition of image data on the biological behaviour of tumour, as well as the anatomical localisation and extent of tumour spread. Because of the small but not negligible risk of radiation induced secondary cancers and the significantly improved overall survival rates of children with cancer, there is an increasing interest in the use of alternative imaging techniques that do not use ionising radiation. Magnetic resonance imaging (MRI) is a radiation-free imaging tool that allows for acquiring images with a high spatial resolution and excellent soft tissue contrast throughout the body. Moreover, recent technological advances have resulted in fast diagnostic sequences for whole-body MR imaging (WB-MRI), including functional techniques such as diffusion weighted imaging. In this review, the current status of the technique and major clinical applications of WB-MRI in children with cancer will be discussed

Whole-body MRI in paediatric oncology

Imaging plays a crucial role in the diagnosis and follow-up of paediatric malignancies. Until recently, computed tomography (CT) has been the imaging technique of choice in children with cancer, but nowadays there is an increasing interest in the use of functional imaging techniques like positron emission tomography and single-photon emission tomography. These later techniques are often combined with CT allowing for simultaneous acquisition of image data on the biological behaviour of tumour, as well as the anatomical localisation and extent of tumour spread. Because of the small but not negligible risk of radiation induced secondary cancers and the significantly improved overall survival rates of children with cancer, there is an increasing interest in the use of alternative imaging techniques that do not use ionising radiation. Magnetic resonance imaging (MRI) is a radiation-free imaging tool that allows for acquiring images with a high spatial resolution and excellent soft tissue contrast throughout the body. Moreover, recent technological advances have resulted in fast diagnostic sequences for whole-body MR imaging (WB-MRI), including functional techniques such as diffusion weighted imaging. In this review, the current status of the technique and major clinical applications of WB-MRI in children with cancer will be discussed

Measurements of cervical lymph nodes in children on computed tomography

Background: No normal measurements or specific size criteria have been described for cervical lymph nodes in children. Objective: To determine the normal measurements of cervical lymph nodes in children on CT. Materials and methods: We included 142 children (ages 1–17 years) who underwent cervical CT examination after high-energy trauma. We evaluated axial and coronal 2-mm reconstructions for lymph nodes at six cervical levels. For the largest lymph node at each level, we measured diameters in both the long and short axial axes and the long coronal axis. Results: A total of 733 lymph nodes were measured in 142 children (62% boys, 38% girls). The greatest measured diameters were 14 mm for the short axis in the axial plane, 24 mm for the long axis in the axial plane and 28 mm for the long axis in the coronal plane. The Pearson correlation coefficient for age and lymph node size at Levels IV–VI was in the range of 0.19–0.47. Conclusion: Lymph nodes with an axial short-axis diameter exceeding 15 mm for Level II and 10 mm for all other cervical levels are uncommon in otherwise healthy children

Whole-tumor apparent diffusion coefficient measurements in nephroblastoma : Can it identify blastemal predominance?

PURPOSE: To explore the potential relation between whole-tumor apparent diffusion coefficient (ADC) parameters in viable parts of tumor and histopathological findings in nephroblastoma. MATERIALS AND METHODS: Children (n = 52) with histopathologically proven nephroblastoma underwent diffusion-weighted magnetic resonance imaging (MRI) (1.5T) before preoperative chemotherapy. Of these, 25 underwent an additional MRI after preoperative chemotherapy, shortly before resection. An experienced reader performed the whole-tumor ADC measurements of all lesions, excluding nonenhancing areas. An experienced pathologist reviewed the postoperative specimens according to standard SIOP guidelines. Potential associations between ADC parameters and proportions of histological subtypes were assessed with Pearson's or Spearman's rank correlation coefficient depending on whether the parameters tested were normally distributed. In case the Mann-Whitney U-test revealed significantly different ADC values in a subtype tumor, this ADC parameter was used to derive a receiver operating characteristic (ROC) curve. RESULTS: The 25(th) percentile ADC at presentation was the best ADC metric correlated with proportion of blastema (Pearson's r = -0.303, P = 0.026). ADC after preoperative treatment showed moderate correlation with proportion stromal subtype at histopathology (r = 0.579, P = 0.002). By ROC analysis, the optimal threshold of median ADC for detecting stromal subtype was 1.362 × 10(-3) mm(2) /s with sensitivity and specificity of 100% (95% confidence interval [CI] 0.65-1.00) and 78.9% (95% CI 0.57-0.92), respectively. CONCLUSION: ADC markers in nephroblastoma are related to stromal subtype histopathology; however, identification of blastemal predominant tumors using whole-tumor ADC measurements is probably not feasible.

Intra- and interobserver variability of whole-tumour apparent diffusion coefficient measurements in nephroblastoma : a pilot study

Background: The apparent diffusion coefficient (ADC) is potentially useful for assessing treatment response in nephroblastoma (Wilms tumour). However the precision of ADC measurements in these heterogeneous lesions is unknown. Objective: To assess intra- and interobserver variability of whole-tumour ADC measurements in viable parts of nephroblastomas at diagnosis and after preoperative chemotherapy. Materials and methods: We included children with histopathologically proven nephroblastoma who had undergone MRI with diffusion-weighted imaging before and after preoperative chemotherapy. Three independent observers performed whole-tumour ADC measurements of all lesions, excluding non-enhancing areas. One observer evaluated all lesions on two occasions. We performed analyses using Bland–Altman plots and concordance correlation coefficient (CCC) calculations with 95% limits of agreement for median ADC, difference between pre- and post-chemotherapy median ADC (ADC shift) and percentage of pixels with ADC values −3 mm2/s. Results: In 22 lesions (13 pretreatment and 9 post-treatment) in 10 children the interobserver variability in median ADC and ADC shift were within the interval of approximately ±0.1 × 10−3 mm2/s (limits of agreement for median ADC ranged −0.08–0.11 × 10−3 mm2/s and for ADC-shift −0.11–0.09 × 10−3 mm2/s). The interobserver variability for percentage of low-ADC pixels was larger and also biased. The calculated CCC confirmed good intra- and interobserver agreement (ρ-c ranging from 0.968 to 0.996).  Conclusion: Measurements of whole-tumour ADC values excluding necrotic areas seem to be sufficiently precise for detection of chemotherapy-related change