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Advanced Ultrasound Techniques for Pediatric Imaging Misun Hwang, MD,A Maciej Piskunowicz, MD, Phd,A,B Kassa Darge, MD, Phda

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Advanced Ultrasound Techniques for Pediatric Imaging Misun Hwang, MD,A Maciej Piskunowicz, MD, Phd,A,B Kassa Darge, MD, Phda Advanced Ultrasound Techniques for Pediatric Imaging Misun Hwang, MD,a Maciej Piskunowicz, MD, PhD,a,b Kassa Darge, MD, PhDa Ultrasound has become a useful tool in the workup of pediatric patients abstract because of the highly convenient, cost-effective, and safe nature of the examination. With rapid advancements in anatomic and functional ultrasound techniques over the recent years, the diagnostic and interventional utility aDepartment of Radiology, Children’s Hospital of of ultrasound has risen tremendously. Advanced ultrasound techniques Philadelphia and Perelman School of Medicine, University of constitute a suite of new technologies that employ microbubbles to provide Pennsylvania, Philadelphia, Pennsylvania; and bDepartment contrast and enhance flow visualization, elastography to measure tissue of Radiology, Medical University of Gdansk, Gdansk, Poland stiffness, ultrafast Doppler to deliver high spatiotemporal resolution of flow, Dr Hwang conceptualized and wrote the manuscript; three- and four-dimensional technique to generate accurate spatiotemporal Drs Piskunowicz and Darge contributed to the writing and image acquisition; and all authors representation of anatomy, and high-frequency imaging to delineate anatomic approved the final manuscript as submitted and structures at a resolution down to 30 mm. Application of these techniques can agree to be accountable for all aspects of the work. enhance the diagnosis of organ injury, viable tumor, and vascular pathologies This trial has been registered at www.clinicaltrials. at bedside. This has significant clinical implications in pediatric patients who gov (identifiers NCT03549507 and NCT03549520). are not easy candidates for lengthy MRI or radiation-requiring examination, DOI: https://doi.org/10.1542/peds.2018-2609 and are also in need of a highly sensitive bedside technique for therapeutic Accepted for publication Nov 19, 2018 guidance. To best use the currently available, advanced ultrasound techniques Address correspondence to Misun Hwang, MD, for pediatric patients, it is necessary to understand the diagnostic utility of Section of Neonatal Imaging, Division of Body ’ each technique. In this review, we will educate the readers of emerging Imaging, Department of Radiology, Childrens Hospital of Philadelphia, Perelman School of ultrasound techniques and their respective clinical applications. Medicine, University of Pennsylvania, 3401 Civic Center Blvd, Philadelphia, PA 19104. E-mail: [email protected] PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, Ultrasound in which advanced which reflects tissue composition 1098-4275). techniques are used can enhance the and/or architecture, edema, injury, Copyright © 2019 by the American Academy of diagnostic sensitivity of conventional and perfusion. The technique Pediatrics grayscale and color Doppler ultrasound provides a quantitative or FINANCIAL DISCLOSURE: Dr Hwang has received while offering additional functional semiquantitative measure of the funding from the National Institutes of Health KL2 information. In contrast-enhanced tissue evaluated. Two main types of award. Dr Piskunowicz has received funding from ultrasound (CEUS), intravascular National Science Center grant DEC-2012/05/B/NZ5/ elastography include strain and shear 01554. Dr Darge has financial relationships with microbubble agents are used to elastography. Strain elastography can Bracco Diagnostics Inc, Lantheus Medical Imaging, highlight perfusion abnormalities produce a semiquantitative measure Philips Healthcare, and Siemens Healthineers. associated with various pathologies, of tissue stiffness by detecting axial FUNDING: Funded by the National Institutes of Health including organ injury and residual displacements arising from either KL2 award and Radiological Society of North America tumors, which would otherwise be manual compression or internal Research Scholar Grant (Dr Hwang) and National challenging to identify with Science Center grant DEC-2012/05/B/NZ5/01554 – physiologic motion (eg, respiration conventional ultrasound.1 3 The (Dr Piskunowicz). Funded by the National Institutes and heartbeat). Shear-wave of Health (NIH). enhanced diagnostic sensitivity of CEUS elastography applies high-intensity can negate the need for further high- POTENTIAL CONFLICT OF INTEREST: The authors have pulses to deform the tissue and indicated they have no potential conflicts of interest cost, cross-sectional imaging requiring produce laterally propagating shear to disclose. sedation. waves that can be used to quantify Elastography is another functional stiffness. Elastography is approved by To cite: Hwang M, Piskunowicz M, Darge K. ultrasound technique that allows for the Food and Drug Administration Advanced Ultrasound Techniques for Pediatric Imaging. Pediatrics. 2019;143(3):e20182609 the quantification of tissue stiffness, (FDA) for the evaluation of all Downloaded from www.aappublications.org/news by guest on September 30, 2021 PEDIATRICS Volume 143, number 3, March 2019:e20182609 STATE-OF-THE-ART REVIEW ARTICLE abdominal organs in pediatric encapsulated microbubbles of 2 to We present a challenging case of patients. 3 µm in size (compared with 7–8 µm a large congenital hepatic of red blood cells) that generate an hemangioma diagnosed with CEUS on Furthermore, improvements in three- increased ultrasound signal because initial scanning that would have dimensional (3D) ultrasound of a high acoustic impedance otherwise been a diagnostic challenge techniques enable accurate mismatch. Lumason (Bracco with conventional ultrasound alone quantification and delineation of Diagnostics Inc, Monroe, NJ), sulfur (Fig 1). The lesion demonstrated anatomic structures for improved hexafluoride gas-filled microbubbles heterogeneous echotexture and an diagnosis and surgical guidance. The encapsulated by phospholipids, was integration of four-dimensional (4D) indeterminate color Doppler signal. approved for characterization of focal ultrasound, with the fourth With a CEUS scan, however, the lesion liver lesions and evaluation of dimension representing time, allows proved to have avid enhancement in vesicoureteral reflux by the FDA in for 3D depiction of moving objects, the periphery, to the same degree as 2016.6 The technique requires such as the heart valves in the aorta, and partial centripetal injection of the manually fi echocardiography. There is ongoing lling on day 2 of life (Supplemental reconstituted contrast agent into research to simultaneously scan the Video 1). The diagnosis of a peripheral vein and detecting the whole-organ volume without hemangioma was made at the time. signal reflected from the reconstructive postprocessing, which, Subsequent scans obtained monthly microbubbles flowing in the vessels. if successful, will significantly until 8 months revealed progressive Its safety profile is much superior to advance the clinical potential of 3D irregular enhancement of the computed tomography (CT) and MRI ultrasound.4 periphery of the lesion, still contrast agents.7,8 The contrast agent enhancing avidly as the aorta, with an Ultrafast Doppler (UfD) is an is primarily exhaled and not renally increase in the size of the lesion. MRI advanced Doppler technique with cleared. Because of the excretion obtained at 8 months of life revealed significantly higher temporal through the lungs, the contrast agent the same peripherally avid resolution than conventional Doppler can be safely given to patients with enhancement pattern seen on CEUS (up to 100 000 frames per second as renal insufficiency. In addition, it acquired the same month. A biopsy opposed to 50 frames per second), allows for an ultrasound study with was performed because of the offering real-time blood volume contrast, avoiding the radiation of CT increasing size of the lesion, and the changes shown to correlate with and the sedation needed for MRI. diagnosis of congenital hemangioma 5 neuronal activation. Moreover, high- These serve as major advantages in was made. Subsequent CEUS of the resolution imaging in which pediatric imaging. CEUS is also lower lesion performed 2 months after the a frequency of up to 70 MHz in cost compared with CT or MRI. MRI revealed a slight decrease in the (compared with conventional imaging size of the lesion and a smoother with a frequency of up to 15 MHz) is echotexture and enhancement Benign Focal Parenchymal Lesions used can enhance the diagnostic pattern, most compatible with rapidly sensitivity of various dermatologic, The main benefit of CEUS in small involuting congenital hemangioma. neuromuscular, vascular, and other children is the ability to diagnose superficial pathologies because of the certain benign focal lesions, such as The above case represents an improved resolution in the region hemangioma, focal nodular example in which increased CEUS close to the transducer. hyperplasia, or fatty infiltration, experience and familiarity within the In this review, we will highlight obviating the need for expensive medical community would have recent advancements in anatomic and radiation or sedation requiring, at prevented a biopsy, which is not functional ultrasound techniques that times, lengthy cross-sectional without risks, especially because the have the potential to significantly imaging. Hemangiomas have lesion was seen to regress in size at improve the diagnostic and a characteristic centripetal pattern of 10 months of life. Noninvasive therapeutic potential of ultrasound. enhancement, with avid peripheral monitoring of the lesion with CEUS fi Our goal for the review is to educate
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