What’s new in Pediatric Imaging – April 2021

3 weeks ago

 

BODY IMAGING

 

Assessment of distal ureteral and ureterovesical junction visualization on contrast-enhanced voiding urosonography.

Benya E, Prendergast FM, Liu D, et al.

Pediatr Radiol Published online 2021;

https://doi.org/10.1007/s00247-021-04979-z.

Question(s) Can contrast enhanced voiding urosonography (CEVUS) replace fluoroscopic voiding cystourethrogram in assessing the distal ureters and ureterovesical junction?

Design Retrospective study between June 2018 and March 2019

Setting Single institution (Ann & Robert Lurie Children’s Hospital, Chicago, IL)

Participants Retrospective review of 34 CEVUS studies in patients with unilateral or bilateral reflux.

Outcomes 2 pediatric radiologists reviewed images from CEVUS and assessed visualization of the distal ureter and ureterovesical junction on a 3-point scale: clear, limited, or absent visualization. They also addressed visualization of any ureteral duplication, periureteral diverticula, or ureteroceles.

Results 34 CEVUS demonstrated vesicoureteral reflux (VUR) in a total of 67 urinary tracts (one patient had a single kidney). Of the 67, reflux was seen in 52 by one reader and 53 by the other. There was low interobserver agreement in visualization of the ureterovesical junction and moderate agreement in distal ureteral visualization. However, there was high interobserver agreement in assessing for ureteral duplication, diverticula, and ureteroceles.

Commentary While CEVUS may detect VUR, evaluation of the distal ureter and ureterovesical junction is limited. Therefore, anatomical variations of these structures can be missed. Voiding cystourethrogram should remain the primary examination if surgical management of VUR is required.

 

Contrast-enhanced ultrasonography in the evaluation of Crohn disease activity in children: comparison with histopathology.

Ponorac S, Gosnak RD, Urlep D, et al.

Pediatr Radiol 2020; 51, 410-418.

https://doi.org/10.1007/s00247-020-04870-3.

Question(s) Can contrast enhanced ultrasound be used to evaluate disease activity in children with Crohn disease?

Design Prospective study from January 2018 to February 2019.

Setting Single center (University of Ljubljana, Ljubljana, Slovenia)

Participants 24 children with Crohn disease with histopathology confirmed active disease with a total of 40 small and large bowel segments (specifically ileum, cecum, and colon) evaluated with ultrasound. Histopathology specimens were obtained by endoscopic biopsy of normal and inflamed mucosa of the colon and terminal ileum.

Outcomes Objective analysis of contrast enhanced ultrasound using peak enhancement value and then subjective analysis to characterize inflammation as none/mild or moderate/severe. Histopathology was used as the reference standard for diagnosis.

Results Histopathology identified moderate to severe inflammation in 18 bowel segments (45%) and remission or mild inflammation in 22 segments (55%). Objective analysis of contrast-enhanced ultrasound using peak enhancement value over 6.9 had a sensitivity of 72%, specificity of 100%, and diagnostic accuracy of 88% for determining moderate to severe inflammation. Subjective analysis of contrast- enhanced ultrasound had a sensitivity of 78%, specificity of 77%, and diagnostic accuracy of 78% for moderate to severe inflammation. Five bowel segments resulted as false negatives.

Commentary While contrast-enhanced ultrasound was able to identify the majority of moderate to severe inflammation, it was unable to identify all cases. Perhaps contrast-enhanced ultrasound could be used as a complementary method in the evaluation of Crohn disease such as for monitoring treatment response. A limitation of generalizability is that not all institutions perform contrast-enhanced ultrasound in children.

 

Diagnostic sensitivity and specificity of CT angiography for renal artery stenosis in children.

Orman G, Masand PM, Kukreja KU et al.

Pediatric Radiology 2021;51:419-426.

https://doi.org/10.1007/s00247-020-04852-5.

Question(s) What are the sensitivity and specificity of CT angiography (CTA) compared to the reference standard of digital subtraction angiography (DSA) for evaluation of hypertension secondary to renal artery stenosis (RAS)?

Design Retrospective study from January 2012 to May 2019

Setting Single-center study (Texas Children’s Hospital, Houston, TX)

Participants 23 patients (mean age 6 years, 3 months) with a total of 59 renal arteries with DSA correlation

Outcomes Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of CTA

Results The sensitivity for CTA for RAS diagnosis was 90% and the specificity was 89.7%. The PPV and NPV for CTA were 81.8% and 94.6%, respectively. The accuracy of CTA was 89.8%.

Commentary This study determined the diagnostic value of CTA for RAS in a pediatric population using DSA correlation as the reference standard, which is a major strength of the study. Limitations of the study include retrospective review of the medical records and radiology reports (rather than imaging review of the CTAs), lag time between the CTA and the DSA, and inherent technical variability between different CT scanners.

 

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

Janssen CL, Littooij AS, Fiocco M et al.

Pediatric Radiology 2021;51:427-434.

https://doi.org/10.1007/s00247-020-04871-2.

Question(s) What is the diagnostic value of MRI in differentiating benign from malignant ovarian tumors in children and adolescents?

Design Retrospective study from October 2014 to March 2019; MR images were reviewed independently by 2 radiologists (10 and 2 years of experience), who were blinded to the clinical information and pathological results

Setting Single-center (Princess Maxima Center for Pediatric Oncology, Utrecht, The Netherlands)

Participants 30 girls age <18 years, who underwent MRI for an ovarian tumor

Outcomes Demographic (age, menarcheal status), clinical (presentation of symptoms, duration of symptoms), radiologic (diameter, cystic morphology, high T1 signal, iso/low T2 signal or solid components, contrast enhancement of solid components, margin, extracapsular growth, lymphadenopathy, ascites, peritoneal deposits, distant metastasis, ADC values), biochemical (AFP, b-HCG, lactate dehydrogenase, CA-125, inhibin-B) and pathologic (benign: mature teratomas, fibrothecomas, grade 1 immature teratomas), borderline: epithelial ovarian tumors, or malignant: grade 2 or 3 immature teratomas, Sertoli-Leydig cell tumors, granulosa cell tumors) data were collected. The sensitivity and specificity for each radiologic finding and kappa statistics were determined.

Results Interobserver agreement ranged from fair (0.283) to very good (0.839). Tumor size > 8 cm had a positive predictive value of 65% and a negative predictive value of 100%; tumor size > 8 cm with enhancing solid components have a positive predictive value 86% and a negative predictive value 93%. Presence of irregular margins, extracapsular tumor growth, and ascites were also indicative of malignancy. The sensitivity and specificity of the overall radiologic assessment were both 100%. There was considerable overlap in ADC values between benign and malignant tumors: the range of ADC values for benign tumors was 0.974-1.255×10-3 mm2/s, and the range for malignant tumors was 0.729-1.509×10-3 mm2/s.

Commentary The authors conclude that MRI assessment of ovarian tumors in children and adolescents can differentiate between benign and malignant tumors, particularly if tumors are larger than 8 cm and have enhancing solid components with ascites, peritoneal deposits, or extracapsular growth. This may have valuable preoperative implications regarding surgical approach. However, there are several limitations. All patients included in the study were referred to a pediatric oncologic center because they already had a diagnosis suspicious for malignancy, resulting in inclusion bias. The small sample size limited determining statistical significance or correlation for ADC values and malignancy.

 

Immediate chest radiograph interpretation by radiographers improves patient safety related to nasogastric feeding tube placement in children.

Keyte E, Roe G, Jeanes Annmarie, et al.

Pediatr Radiol. Published online 10 March 2021.

https://doi.org/10.1007/s00247-021-05032-9.

Question(s) Can radiographers (radiology technicians) be safely trained to preview radiographs for appropriate nasogastric (NG) tube positioning?

Design Retrospective audit over a 13-month period between October 2018 and October 2019

Setting Single Institution (Leeds Children’s Hospital at the Leeds General Infirmary, Leeds, UK)

Participants 282 radiographs performed for NG tube placement in children 0-16 years of age.

Outcomes Correlation of radiographer interpretation and comments with final read by radiologist, appropriate communication with referring provider. Radiographers received special training in interpreting NG tube checks and had to follow a specific workflow for interpretation and communication.

Results Of the 282 studies performed, 240 (85.1%) used the appropriate radiographer reporting work flow for single NG tube checks. Of these 240, 235 (97.9%) fully agreed with final radiologist interpretation. The discrepancies mainly reflected differences in the length of the NG tube below the diaphragm and recommendation for advancement. Of the 240, 213 (88.8%) were deemed safe to use, 11 (4.6%) were too high, and 16 (6.7%) needed to be removed.

Commentary This study demonstrates that with proper training and a strict workflow, radiographers (radiology technicians) can safely screen for proper NG tube placement. However, improper training or deviation from the work flow could lead to serious safety issues, and a final radiologist read should always be provided. Also, this system may not be needed at institutions with overnight radiologist staff or resident coverage.

 

INTERVENTIONAL RADIOLOGY

 

Confirmatory radiographs have limited utility following ultrasound-guided tunneled femoral central venous catheter placements by interventional radiology.

Lewis SB, Chick JFB, Koo KS, et al.

Pediatr Radiol. Published online 2021;

https://doi.org/10.1007/s00247-020-04957-x.

Question(s) Are radiographs necessary to confirm placement of ultrasound-guided femoral venous catheters?

Design Retrospective cohort study between January 2016 and April 2020.

Setting Single center (University of Washington, Seattle Children’s Hospital, Seattle, WA)

Participants: 484 pediatric patients who underwent bedside ultrasound guided tunneled femoral catheter placement.

Outcomes Technical success, adverse events, post-procedure radiographic practices and inter-modality catheter tip concordance. Technical success was defined at transfemoral placement of catheter with appropriate tip positioning. Appropriate catheter tip placement and concordance was defined as the tip between the lower right atrium or hepatic IVC on both examinations.

Results Technical success was achieved in 481 of 484 patients (99.4%). Ultrasound was able to confirm catheter placement in all 481 successfully placed catheters. 171 confirmatory radiographs were obtained, all of which demonstrated catheter tip concordance with intraprocedural ultrasound. Adverse events occurred in 5 (1.0%) of patients and included hematoma, occlusive iliofemoral thrombosis, arterial access, and supraventricular tachycardia.

Commentary This study demonstrated high concordance between intraprocedural ultrasound and radiographs in confirming femoral catheter placement, suggesting that confirmatory radiographs are not required if the catheter tip is seen with ultrasound. This could reduce the number of radiographs performed on hospitalized patients and thus radiation received. However, limitations of the study include the retrospective nature and single center design, in which success could be related to technical skill of the institution’s interventional radiologists.

 

Contemporary management of pediatric blunt splenic trauma: a national trauma databank analysis.

Shinn K, Gylard S, Chahine A et al.

JVIR. 2021:1-11. Article in Press.

https://doi.org/10.1016/j.jvir.2020.11.024.

Question(s) What are the quantified changes in the management of pediatric patients with isolated splenic injury?

Design Retrospective study, search of the National Trauma Data Bank (NTDB) from 2007 to 2015 using diagnostic codes for any grade of splenic trauma.

Setting National Trauma Data Bank

Participants 24,128 patients below age 18 years with splenic injury were identified. Patients with splenic injury with any grade of aortic injury, grade III or higher brain or spinal injury, grade IV or V liver or kidney injury, pelvic trauma, penetrating injury, or who were dead on arrival were excluded to avoid mortality confounders. Lower grade solid organ injuries were not excluded due to minimal effect on overall mortality.

Outcomes Management trends (rates of techniques, clinical outcomes, and failure rates) during the study period were described. Management covariates [non-operative management (NOM), splenectomy, splenic repair, IR angiography with embolization, or combination therapy as defined by 2 or more of the previously mentioned techniques] were determined and included in the analysis. Additional demographic and clinical covariates (age, sex, systolic blood pressure on admission, AAST grade of splenic injury from I to V) and outcomes covariates [length of stay (LOS) days, ICU days, and ventilator days) were evaluated. Time to intervention (in hours) and mortality rate were also collected.

Results Overall, the majority of patients underwent NOM (90.3%), followed by splenectomy (5.6%), splenic artery embolization (2.7%), splenic repair (1.1%) and combination therapy (0.3%). Rate of NOM did not significantly change from 90% to 91%. Rate of embolization increased from 1.5% to 3.5%. Rate of splenectomy decreased from 6.9% to 4.4%. NOM was associated with the shortest LOS overall at 5.1 days, which was significantly lower compared to splenectomy, embolization, and combination therapy (10.1, 7.4, and 12.4 days, respectively; P<0.001 for each). NOM was also associated with the shortest ICU stay with 1.9 days compared to splenectomy, embolization and combination therapy (4.5, 3.4 and 6.8 days, respectively; P<0.001). After adjusting for age, sex, baseline SBP, type of facility, and grade of splenic injury, patients with NOM had the lowest mortality rate, followed by embolization, though without statistical significance. Splenectomy and combination therapy had significantly higher mortality rates in compared to embolization or NOM.

Commentary The study showed that NOM for splenic injury is common, effective and associated with favorable outcomes, compared to surgical intervention. The results from this study showed that there is an increasing trend of splenic artery embolization for splenic injuries that do require intervention. A limitation of the study is that the data collected may not be generalizable nationally due to the voluntary nature of the databank. Additionally, outcomes of 30-day survival or further long-term follow-up were not assessed.

 

NEURORADIOLOGY

 

Fetal brain MRI findings predict neurodevelopment in children with tuberous sclerosis complex.

Hulsof HM, Slot EMH, Lequin M, et al.

J Pediatr. Published online 2021,

https://doi.org/10.1016/j.jpeds.2021.02.060.

Question(s) Can fetal MRI brain findings predict epilepsy characteristic and neurodevelopment in children with tuberous sclerosis complex (TSC)?

Design Retrospective cohort study

Setting 6 centers across EPISTOP consortium, a multicenter, randomized, long-term prospective study in Europe and Australia that evaluates epileptogenesis in TSC.

Participants: 41 children with a definitive diagnosis of TSC who had fetal MRI of sufficient quality as well as available neurologic outcome data at 2 years of age.

Outcomes The presence, number, and size of subcortical tubers for each of the 8 cerebral lobes and 2 cerebellar hemispheres. Subependymal nodules and white matter disease were not evaluated.

Results Fetal MRI demonstrated subcortical lesions in all but one patient. At 2 years old, 58.5% of patients had epilepsy and 22% had drug-resistant epilepsy. Cognitive, language, and motor development were delayed in 38%, 81%, and 50% of patients, respectively. 20.5% were diagnosed with autism spectrum disorder. High number of fetal MRI lesions was significantly associated with delayed cognitive development, motor development, and autism diagnosis, but not with epilepsy diagnosis.

Commentary Fetal MRI can be used to determine neurologic burden of tubers in patients with TSC. Higher lesion burden correlates with delayed cognitive and motor development as well as autism. The authors hypothesize that the decreased number of patients with epilepsy in their study is due to earlier diagnosis and preventative treatment. While fetal MRI may not be widely available, it can help with early parental counseling and treatment of children with suspected/confirmed TSC.

 

Uncomplicated intraventricular hemorrhage is not associated with lower estimated cerebral volume at term age.

Graca AM and Cowan FM.

European Journal of Paediatric Neurology. 2021. Journal Pre-Proof.

https://doi.org/10.1016/j.ejpn.2021.01.002.

Question(s) Are uncomplicated intraventricular hemorrhages (IVH) associated with poor outcomes, as measured by cerebral brain volume by cranial ultrasound (cUS) at term-equivalent age (TEA)?

Design Prospective cohort of preterm infants born between 2014 and 2017. A historical cohort of preterm infants born between 2008 and 2010 and without abnormality on cUS was used to establish the original model (control).

Setting Single-center study (NICU of Centro Hospitalar Universitario de Lisboa Norte, Portugal)

Participants 18 preterm infants of <32 weeks’ gestation with grade 2 or 3 IVH detected on cUS during the 1st week after birth; 71 preterm infants had normal scans.

Outcomes Estimated cranial volume. (cm3), estimated cerebral volume (cm3), Levene ventricular index (mm), thalamo-occipital distance (mm); additional clinical factors [such as prenatal steroids, Apgar score, clinical risk index for babies (CRIB) score, invasive ventilation, inotropes, patent ductus arteriosus (PDA) treatment, culture-proven sepsis, necrotizing enterocolitis surgery, significant retinopathy of prematurity, chronic lung disease, and post-natal steroids] were also analyzed between the 2 groups.

Results Preterm infants with IVH grade 2 and 3 had lower gestational age (GA) and birth weight than preterm infants with normal scans (P<0.001 and P<0.05, respectively). Using the 3D model and adjusting for GA, there was no significant difference at TEA for cranial and cerebral volumes between the infants with uncomplicated IVH and the infants with normal scans. The Levene ventricular index was significantly higher for patients with IVH (P<0.05). No difference was seen for the thalamo-occipital distance between the 2 groups. Uncomplicated IVH in preterm infants was associated with multiple negative clinical factors and complications, including lower Apgar scores, higher CRIB scores, higher need for invasive ventilation and PDA treatment, and presence of sepsis.

Commentary The authors conclude that uncomplicated IVH is not associated with lower estimated cerebral volume, which they suggest may be implicated in neurodevelopmental prognosis. Limitations of the study include using a historical rather than contemporaneous cohort  as the control, not following up with brain MRI to validate the results, and not addressing neurodevelopment of their cohort.

 

Utility of skull radiographs in infants undergoing 3D head CT during evaluation for physical abuse.

Pennell C, Aundhia M, Malik A et al.

J Ped Surg. 2021. Journal Pre-Proof.

https://doi.org/10.1016/j.jpedsurg.2021.02.037.

Question(s) What is the accuracy of 3D head CT (3DCT) and skull radiography (SR) for detecting skull fractures in infants? Does SR add any diagnostic information to a physical abuse evaluation that was not already obtained from a 3DCT?

Design Retrospective review from January 2017 to December 2018. Two radiologists reviewed the imaging studies. Diagnostic accuracy was compared using McNemar’s test.

Setting Single center study at an urban level 1 pediatric trauma center (St. Christopher’s Hospital for Children, Philadelphia, PA).

Participants 158 infants up to age 12 months (mean age 5 months), who underwent 3DCT and SR.

Outcomes Interobserver reliability (kappa statistics) for SR and 3DCT, relative diagnostic accuracy of SR compared to 3DCT. Fracture location and type were also described on both modalities.

Results The most common location for fracture on both 3DCT and SR was the parietal calvarium. The most common fracture type identified on both 3DCT and SR was a simple, linear fracture. On 3DCT, Radiologist 1 identified fractures in 28.5% of children, while Radiologist 2 identified fractures in 29.1%. Overall concordance for fracture identification was 98.1% (k=0.95, almost perfect agreement). On SR, Radiologist 1 identified fractures in 34.2% of children, while Radiologist 2 identified fractures in 23.4%. Overall concordance was 85.5% (k=0.65, substantial agreement). The diagnostic accuracy of 3DCT and SR for detection of skull fractures was not significantly different (P=0.211).

Commentary The authors determined that SR does not have added benefit in identifying skull fractures in infants already undergoing 3DCT for physical abuse evaluation because there was no difference between 3DCT and SR for detecting skull fractures and because the interobserver reliability was nearly perfect for 3DCT analysis (over SR). The results of this study are not particularly surprising as they are in concordance with various studies referenced in the article; furthermore, certain pediatric institutions may have protocols that already exclude obtaining a SR for fractures if the patient is planning to have/has already had a 3DCT. Nonetheless, the data support the authors’ hypothesis.

References
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