Imaging of pediatric gastrointestinal tumors: A tertiary center experience over 19 years.

PURPOSE: Gastrointestinal tract (GIT) tumors in children are rare and there is a scarcity of data on their imaging features. The purpose of this study was to determine thefrequency of various GIT tumor types in children and to identify key imaging characteristics. METHODS: This retrospective, single-center study was approved by the local ethics committee. Children with histologically proven GIT tumours (malignantand benign) who had imaging available on the institutional PACS between May 1, 2000 and Dec 31, 2019 were included. Demographic data and available imaging was reviewed by two blinded radiologists. RESULTS: In total, 90 children (45 male, mean age 9.3 ± 4.3 years) with GIT tumours were included. The final diagnoses included polyps (n = 28), lymphomas/PTLD (n = 27), neuroendocrine tumours (n = 16), adenocarcinoma (n = 6), adenoma (n = 5), gastrointestinal stromal tumor (GIST) (n = 3), inflammatory myofibroblastic tumours (n = 2) and lastly leiomyoblastoma, leiomyoma and lipoma (1 each). All GIT segments were affected, but overall the small and large bowel had most lesions. Eighty-one percent children had a single lesion while remaining 19 % had multiple lesions. The neoplastic process manifested as intra-luminal lesion (58 %) or wall thickening (42 %) on imaging. Multiple cystic areas and vascular pedicle for polyps; and hypoechogenecity of the mass or wall thickening and aneurysmal dilatation for lymphomas, were the characteristic imaging features. None of the neuroendocrine tumours affecting appendix were seen on pre-resection imaging. CONCLUSIONS: Variety of benign and malignant tumors are seen throughout the childhood. Polyps, lymphomas and appendiceal neuroendocrine tumors are common lesions. Characteristic imaging features of juvenile polyps and lymphomas on ultrasound may help narrowing the differentials, and guide further work up.

Improving protocols for whole-body magnetic resonance imaging: oncological and inflammatory applications.

Whole-body MRI is increasingly used in the evaluation of a range of oncological and non-oncological diseases in infants, children and adolescents. Technical innovation in MRI scanners, coils and sequences have enabled whole-body MRI to be performed more rapidly, offering large field-of-view imaging suitable for multifocal and multisystem disease processes in a clinically useful timeframe. Together with a lack of ionizing radiation, this makes whole-body MRI especially attractive in the pediatric population. Indications include lesion detection in cancer predisposition syndrome surveillance and in the workup of children with known malignancies, and diagnosis and monitoring of a host of infectious and non-infectious inflammatory conditions. Choosing which patients are most likely to benefit from this technology is crucial, but so is adjusting protocols to the patient and disease to optimize lesion detection. The focus of this review is on protocols and the elements impacting image acquisition in pediatric whole-body MRI. We consider the practical aspects, from scanner and coil selection to patient positioning, single-center generic and indication-specific protocols with technical parameters, motion reduction strategies and post-processing. When optimized, collectively these lead to better standardization of whole-body MRI, and when married to systematic analysis and interpretation, they can improve diagnostic accuracy.

Case Report: MRI, CEUS, and CT Imaging Features of Metanephric Adenoma with Histopathological Correlation and Literature Review.

The metanephric adenoma is an extremely rare, benign, embryonal-epithelial neoplasm of the kidney and has a good prognosis with appropriate treatment. It can present at any age and is often asymptomatic. Histologically, the lesion is well established; however, there have been only a few cases described with available detailed imaging findings, most of them with large renal masses typically depicted by computed tomography (CT). This case report includes imaging of contrast-enhanced MRI, contrast-enhanced ultrasound (CEUS), and CT, and thus adds to the information available, potentially promoting a nephron-sparing clinical pathway. We report on the clinical presentation, imaging, histopathological diagnosis, and treatment data of a 27-year-old female, in whom an incidental, symptomatic kidney tumor was detected. CT, CEUS, and MRI showed a suspicious unifocal renal lesion with inhomogeneous enhancement, which was indistinguishable from renal cell carcinoma. After laparoscopic resection, a metanephric adenoma with microscopically partially glandular, partially nest-like solid growth and without distinctive atypia was diagnosed pathohistologically. Immunohistochemistry results were positive for Wilms Tumor 1 and CD57 and negative for EMA and CK7: 2-3% positive cells in MIB1 coloring. At 3-month and 1-year follow-up, the patient was asymptomatic and imaging showed no recurrence of renal masses or metastases.

Population-based cohort imaging: skeletal muscle mass by magnetic resonance imaging in correlation to bioelectrical-impedance analysis.

BACKGROUND: Skeletal muscle mass is subjected to constant changes and is considered a good predictor for outcome in various diseases. Bioelectrical-impedance analysis (BIA) and magnetic resonance imaging (MRI) are approved methodologies for its assessment. However, muscle mass estimations by BIA may be influenced by excess intramuscular lipids and adipose tissue in obesity. The objective of this study was to evaluate the feasibility of quantitative assessment of skeletal muscle mass by MRI as compared with BIA. METHODS: Subjects from a population-based cohort underwent BIA (50 kHz, 0.8 mA) and whole-body MRI including chemical-shift encoded MRI (six echo times). Abdominal muscle mass by MRI was quantified as total and fat-free cross-sectional area by a standardized manual segmentation-algorithm and normalized to subjects' body height2 (abdominal muscle mass indices: AMMIMRI ). RESULTS: Among 335 included subjects (56.3 ± 9.1 years, 56.1% male), 95 (28.4%) were obese (BMI ≥ 30 kg/m2 ). MRI-based and BIA-based measures of muscle mass were strongly correlated, particularly in non-obese subjects [r < 0.74 in non-obese (P < 0.001) vs. r < 0.56 in obese (P < 0.001)]. Median AMMITotal(MRI) was significantly higher in obese as compared with non-obese subjects (3246.7 ± 606.1 mm2 /m2 vs. 2839.0 ± 535.8 mm2 /m2 , P < 0.001, respectively), whereas the ratio AMMIFat-free /AMMITotal (by MRI) was significantly higher in non-obese individuals (59.3 ± 10.1% vs. 53.5 ± 10.6%, P < 0.001, respectively). No significant difference was found regarding AMMIFat-free(MRI) (P = 0.424). In analyses adjusted for age and sex, impaired glucose tolerance and measures of obesity were significantly and positively associated with AMMITotal(MRI) and significantly and inversely with the ratio AMMIFat-free(MRI) /AMMITotal(MRI) (P < 0.001). CONCLUSIONS: MRI-based assessment of muscle mass is feasible in population-based imaging and strongly correlated with BIA. However, the observed weaker correlation in obese subjects may explain the known limitation of BIA in obesity and promote MRI-based assessments. Thus, skeletal muscle mass parameters by MRI may serve as practical imaging biomarkers independent of subjects' body weight.

Early diagnosis and response assessment in chronic recurrent multifocal osteomyelitis: changes in lesion volume and signal intensity assessed by whole-body MRI.

OBJECTIVE: To assess the effectiveness of whole-body MRI (WB-MRI) in early diagnosis of chronic recurrent multifocal osteomyelitis (CRMO) and the prediction of clinical response through quantitative MRI features. METHODS: 20 children (mean age, 10.3 years; range, 5-14 years) with CRMO underwent WB-MRI and were assessed with a clinical score (Jansson) at baseline (median time after first encounter, 8 months) and follow-up (median time after baseline, 11.5 months). Baseline WB-MRI scans were classified as early (within 6 months after first encounter) and late. Clinical responders and non-responders were compared regarding number and localization of bone lesions, lesion volume and T2 signal intensity (SI) ratio (lesion to muscle). RESULTS: Diagnosis of CRMO was made promptly in the early WB-MRI group (n = 10; median, 3 months) compared to the late WB-MRI group (n = 10; 18 months; p = 0.006). Bone lesions were mainly located in the lower extremities (n = 119/223; 53%). No significant difference was detected regarding the number of bone lesions and lesion volume in the subgroups of clinical responders (n = 10) and non-responders (n = 10). Responders showed a higher volume reduction of bone lesions at follow-up compared to non-responders (p = 0.03). Baseline and follow-up SI ratios were lower in responders (5.6 and 5.8 vs 6.1 and 7.2; p = 0.047 and p = 0.005). CONCLUSION: The use of WB-MRI within 6 months of disease suspicion may serve as a benchmark to support early diagnosis of CRMO. T2 SI ratios and the reduction of lesions' volume correlate with clinical outcome. ADVANCES IN KNOWLEDGE: WB-MRI at an early stage of suspected CRMO plays a key role for early diagnosis. This is the first study showing that quantitative MRI features are suitable for response assessment and can be used as prognostic markers for the prediction of clinical response.

Distribution patterns of intramyocellular and extramyocellular fat by magnetic resonance imaging in subjects with diabetes, prediabetes and normoglycaemic controls.

AIM: To evaluate the distribution of intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs) as well as total fat content in abdominal skeletal muscle by magnetic resonance imaging (MRI) using a dedicated segmentation algorithm in subjects with type 2 diabetes (T2D), prediabetes and normoglycaemic controls. MATERIALS AND METHODS: Subjects from a population-based cohort were classified with T2D, prediabetes or as normoglycaemic controls. Total myosteatosis, IMCLs and EMCLs were quantified by multiecho Dixon MRI as proton-density fat-fraction (in %) in abdominal skeletal muscle. RESULTS: Among 337 included subjects (median age 56.0 [IQR: 49.0-64.0] years, 56.4% males, median body mass index [BMI]: 27.2 kg/m2 ), 129 (38.3%) were classified with an impaired glucose metabolism (T2D: 49 [14.5%]; prediabetes: 80 [23.7%]). IMCLs were significantly higher than EMCLs in subjects without obesity (5.7% [IQR: 4.8%-7.0%] vs. 4.1% [IQR: 2.7%-5.8%], P < .001), whereas the amounts of IMCLs and EMCLs were shown to be equal and significantly higher in subjects with obesity (both 6.7%, P < .001). Subjects with prediabetes and T2D had significantly higher amounts of IMCLs and EMCLs compared with normoglycaemic controls (P < .001). In univariable analysis, prediabetes and T2D were significantly associated with both IMCLs (prediabetes: ß: 0.76, 95% CI: 0.28-1.24, P = .002; T2D: ß: 1.56, 95% CI: 0.66-2.47, P < .001) and EMCLs (prediabetes: ß: 1.54, 95% CI: 0.56-2.51, P = .002; T2D: ß: 2.15, 95% CI: 1.33-2.96, P < .001). After adjustment for age and gender, the association of IMCLs with prediabetes attenuated (P = 0.06), whereas for T2D, both IMCLs and EMCLs remained significantly and positively associated (P < .02). CONCLUSION: There are significant differences in the amount and distribution ratio of IMCLs and EMCLs between subjects with T2D, prediabetes and normoglycaemic controls. Therefore, these patterns of intramuscular fat distribution by MRI might serve as imaging biomarkers in both normal and impaired glucose metabolism.

[Osseous variations in radiological diagnostics of the wrist]. / Ossäre Normvarianten in der radiologischen Diagnostik des Handgelenks.

CLINICAL/METHODICAL ISSUE: The carpal joint is one of the most complex joints in the body comprising multiple bones that allow flexibility while simultaneously providing stability. Variations in osseous structures that may be either cause or result of pathological changes may make radiological reporting challenging. Only the knowledge of important osseous variations allows a reliable assessment of carpal imaging studies. STANDARD RADIOLOGICAL METHODS: The standard imaging technique for evaluation of osseous carpal structures is conventional radiography, which is followed by computed tomography (CT) and-under special circumstances-magnetic resonance imaging (MRI). Other imaging methods such as sonography or nuclear medicine studies do not play a significant role in clinical routine. METHODICAL INNOVATIONS: Apart from continuous reduction in effective radiation dose, there have been no significant methodical improvements in the past decade regarding imaging of osseous carpal structures in clinical routine. PRACTICAL RECOMMENDATIONS: As the initial diagnostic procedure, conventional radiography usually allows a safe and reliable diagnosis of osseous structures. Unclear or discrepant imaging findings between clinical and imaging assessment should initiate further imaging, preferably with CT. Only for certain questions or to reduce effective radiation dose in children MRI studies should be performed in clinical routine.

CT-morphologic and CT-textural patterns of response in inoperable soft tissue sarcomas treated with pazopanib-a preliminary retrospective cohort study.

OBJECTIVE: To analyze patterns of response in soft tissue sarcomas exposed to pazopanib using CT-morphologic and textural features and their suitability for evaluating therapeutic response. METHODS: Retrospective evaluation of CT response and texture patterns in 33 patients (23 female; mean age: 61.2 years, range, 30-85 years) with soft tissue sarcomas treated with pazopanib from October 2008 to July 2017. Response evaluation was based on modified (m)CHOI-criteria and RECISTv.1.1 and classified as partial response (PR), stable disease (SD), progressive disease (PD). The following CT-texture (CTTA)-parameters were calculated: mean, entropy and uniformity of intensity/average/skewness/entropy of co-occurrence matrix and contrast of neighboring-gray-level-dependence-matrix. RESULTS: Following mCHOI-criteria, 12 patients achieved PR, 7 SD and 14 PD. As per RECISTv.1.1 9 patients obtained PR, 9 SD and 15 PD. Frequent patterns of response were tumor liquefaction and necrosis (n=4/33, 12.1% each). Further patterns included shrinkage and cavitation (n=2/33, 6.1% each). In responders, differences in mean heterogeneity (p=0.01), intensity (p=0.03), average (p=0.03) and entropy of skewness (p=0.01) were found at follow-up whereas in non-responders, CTTA-parameters did not change significantly. Baseline-CTTA-features differed between responders and non-responders in terms of uniformity of skewness (p=0.045). Baseline-CTTA-parameters did not correlate with any morphologic response pattern. CONCLUSION: Most frequent patterns of response to pazopanib were tumor liquefaction and necrosis. Single CT-textural features show strong association with the response to pazopanib-although limited in relation to specific response patterns. ADVANCES IN KNOWLEDGE: Tumor liquefication and necrosis are important patterns of response to pazopanib. CT-texture analysis has limited associations with specific response patterns.

Advanced Virtual Monoenergetic Imaging: Improvement of Visualization and Differentiation of Intramuscular Lesions in Portal-Venous-phase Contrast-enhanced Dual-energy CT.

PURPOSE: To evaluate the effect of advanced monoenergetic imaging (MEI+) postprocessing algorithm on the visualization of various intramuscular lesions on portal-venous-phase contrast-enhanced dual-energy computed tomography (DECT). MATERIAL AND METHODS: Thirty-nine patients (64.3 ± 11.1 years; 26 males) with various intramuscular lesions ranging from malignancy, bleeding, inflammation, edematous changes, and benign neoplasms were included and underwent DECT (100/Sn150kV). Postprocessing with MEI+ technique was used to reconstruct images at four different keV levels (40, 60, 80, 100) and compared to the standard portal-venous-phase CT (CTpv) images. Image quality was assessed qualitatively (conspicuity, delineation, sharpness, noise, and confidence) by two independent readers using 5-point Likert scales, 5 = excellent; as well as quantitatively by calculating signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR), and area under the receiver operating characteristic (ROC) curve (AUC) for lesion characterization. RESULTS: Highest lesion enhancement and diagnostic confidence were observed in MEI+ 40 keV, with significant differences to CTpv (p < 0.001), as well as for malignant lesions (highest conspicuity, noise, and sharpness in MEI+ 40 keV; p < 0.001). CNR calculations revealed highest values for MEI+ 40 keV followed by 60 keV with significant differences to CTpv, and increasing energy levels. ROC analysis showed highest diagnostic accuracy for 40-keV MEI+ datasets regarding the detection of malignant/benign lesions with AUC values of 98.9% (95%-confidence interval: 96.5, 100) and a standard error of 1.2, further AUC values decreased to 83.6% for MEI+100. CONCLUSION: MEI+ at low keV levels can significantly improve lesion detection of benign versus malignant intramuscular entities in patients undergoing portal-venous-phase DECT scans due to increased CNR.

Virtual non-enhanced dual-energy CT reconstruction may replace true non-enhanced CT scans in the setting of suspected active hemorrhage.

OBJECTIVE: To assess virtual non-enhanced dual energy computed tomography (DECT) reconstruction as a potential alternative to true non-enhanced thoracic and abdominal CT scans in patients with suspected active hemorrhage. METHODS AND MATERIALS: Ninety-seven consecutive patients with suspected active bleeding, who underwent routine triphasic CT with intravenous contrast, were included. All patients underwent single energy non-enhanced (TNE) and arterial phase CT as well as venous DECT. Using commercially available software, venous dual energy images were used to generate virtual non-enhanced images (VNE). TNE and VNE were evaluated regarding subjective image quality and diagnostic confidence on a 5-point-scale. The consistency of interpretation with respect to presence and type of hemorrhage between conventional triphasic CT including TNE and biphasic CT with simulated VNE was assessed by two blinded independent readers. RESULTS: Among the included subjects (mean age: 66.3 ± 14.5 years, 63.9% male), 37.1% were diagnosed with acute hemorrhage. VNE yielded significantly lower image quality but superior reduction of artefacts as compared to TNE (p ≤ 0.001). Diagnostic confidence was rated high for both TNE and VNE with a significant superiority of TNE (p = 0.003). Triphasic and biphasic CT datasets yielded perfect intrareader agreement regarding presence and type of hemorrhage. The interrater agreement was almost perfect (K = 0.955). Radiation dose was significantly reduced using biphasic dual energy CT with VNE (p ≤ 0.001). CONCLUSION: Virtual non-enhanced images yield comparable diagnostic confidence and perfect agreement with true non-enhanced images for assessment of acute hemorrhage. This suggests that true non-enhanced images could be replaced by virtual non-enhanced images resulting in a significant reduction of radiation dose.

Assessment of the degree of abdominal myosteatosis by magnetic resonance imaging in subjects with diabetes, prediabetes and healthy controls from the general population.

OBJECTIVES: Intra- and intermyocellular lipid deposition and adipose tissue are part of glucose homeostasis and insulin resistance; however, their role in type 2 diabetes mellitus (T2DM) remains unclear. We assessed differences in the degree of abdominal myosteatosis among subjects with T2DM and prediabetes. MATERIALS AND METHODS: Asymptomatic subjects from the general population were classified as subjects with T2DM, prediabetes or healthy controls and underwent multi-echo Dixon magnetic resonance imaging (MRI) (TR 8.90 ms, six echo times, flip-angle 4°). Abdominal myosteatosis was quantified as proton-density fat-fraction (PDFFmuscle) by a standardized segmentation-algorithm. Cardiometabolic risk factors were prospectively obtained in a comprehensive health assessment and visceral and subcutaneous adipose tissue (VAT and SAT) were quantified semi-automatically. Uni- and multivariate quantile regression were used to examine associations. RESULTS: Among 349 included subjects (mean age: 56.0 ±â€¯8.0years, 56.7% males), 45 were classified as subjects with T2DM and 84 with prediabetes (12.9% and 24.1%; respectively). Median PDFFmuscle was significantly higher in subjects with T2DM and prediabetes compared to healthy controls (13.1% (IQR10.5-16.6%); 11.1% (IQR8.9-15.0%) and 10.1% (IQR7.5-13.3%); respectively, p < 0.001). The observed differences were independent of age and gender (all p < 0.002) but attenuated after adjustment for BMI (ß: -0.02, 95%CI: -1.49 to 1.44, p = 0.974; ß: 0.47, 95%CI: -0.91 to 1.86, p = 0.506; prediabetes and T2DM, respectively). This effect was attributable to VAT, which remained independently associated with PDFFmuscle after full adjustment (ß: 0.01, 95%CI: 0.01-0.02, p = 0.002). CONCLUSIONS: There are significant differences in the degree of abdominal myosteatosis between subjects with T2DM, prediabetes and healthy controls, that may be confounded by VAT. However, abdominal myosteatosis by MRI might serve as a cardiometabolic imaging-biomarker, specifically in the setting of impaired glucose metabolism.

T(2) relaxation time measurements are limited in monitoring progression, once advanced cartilage defects at the knee occur: longitudinal data from the osteoarthritis initiative.

PURPOSE: To study the natural evolution of cartilage T2 relaxation times in knees with various extents of morphological cartilage abnormalities, assessed with 3 Tesla MRI from the Osteoarthritis Initiative. MATERIALS AND METHODS: Right knee MRIs of 245, 45- to 60-year-old individuals without radiographic osteoarthritis (OA) were included. Cartilage was segmented and T2 maps were generated in five compartments (patella, medial and lateral femoral condyle, medial, and lateral tibia) at baseline and 2-year follow-up. We examined the association of T2 values and 2-year change of T2 values with various Whole-Organ MR Imaging Scores (WORMS). Statistical analysis was performed with analysis of variance and Students t-tests. RESULTS: Higher baseline T2 was associated with more severe cartilage defects at baseline and subsequent cartilage loss (P < 0.001). However, longitudinal T2 change was inversely associated with both baseline (P = 0.038) and follow-up (P = 0.002) severity of cartilage defects. Knees that developed new cartilage defects had smaller increases in T2 than subjects without defects (P = 0.045). Individuals with higher baseline T2 showed smaller T2 increases over time (P < 0.001). CONCLUSION: An inverse correlation of longitudinal T2 changes versus baseline T2 values and morphological cartilage abnormalities suggests that once morphological cartilage defects occur, T2 values may be limited for evaluating further cartilage degradation.