Paediatric ultrasonography of the liver, hepatobiliary tract and pancreas

Transcutaneous Mediastinal Ultrasonography for Lymphadenopathy in Children: A Pictorial Essay of Technique and Imaging Findings

Ultrasonography (US) forms the mainstay of imaging in children; however, in the chest, its use has traditionally been limited to evaluation of pleural pathology. US techniques such as endobronchial and endoscopic ultrasound, which are commonly used for detection of mediastinal lymphadenopathy are invasive, aerosol generating, and often require sedation. Transcutaneous mediastinal sonography (TMUS) offers a useful alternative, which is easier to perform and overcomes these limitations. In this review, we summarize the technique, as well as imaging appearances of lymph nodes on TMUS. We also list common problems faced by operators and suggest troubleshooting methods for these.

[Imaging of hepatic tumors in children and adolescents]

BACKGROUND

Pediatric liver tumors are relatively rare, but thorough knowledge of their imaging features is still important.

OBJECTIVES

Frequency and imaging features of benign and malignant liver masses during childhood and adolescence.

MATERIALS AND METHODS

Discussion of relevant original articles, review manuscripts and expert recommendations concerning imaging of childhood liver tumors.

RESULTS

The most common malignant tumors of the liver are hepatoblastoma, which usually occur in younger children, as well as in some regions hepatocellular carcinoma. In contrast to most benign masses, such as focal nodular hyperplasia, simple cysts or fatty liver infiltrations, their imaging morphology is not very characteristic. Radiologically, sonography and magnetic resonance imaging (MRI) are used for assessment. Both methods benefit from intravenous contrast agent administration.

CONCLUSIONS

Childhood liver tumors show a broad spectrum of morphological manifestations. Some entities can be characterized using standard imaging, some require multimodal imaging or histological assessment. In addition to morphological imaging criteria, age and the medical history as well as laboratory data play an important role in establishing the correct diagnosis.

Approach to the postnatal sonographic evaluation of prenatally detected abdominopelvic cysts

Prenatally detected abdominal and pelvic masses are commonly cystic in morphology and usually seen on mid-trimester sonography. Sonography is the favored imaging modality for the postnatal evaluation of these lesions in newborns, given its availability, low cost, lack of ionizing radiation, lack of sedation, and high spatial resolution in small patients. The differential diagnosis of abdominopelvic cystic masses in newborns is broad given that they can arise from many organs and may have overlapping features on imaging. This article illustrates an approach to the postnatal sonographic evaluation of prenatally detected cystic abdominal and pelvic masses based on their anatomic location and distinctive sonographic characteristics, which can aid in an accurate diagnosis and guide appropriate management.

Pediatric ultrasonography of the pancreas: normal and abnormal findings

The pancreas is easily investigated in children thanks to the relative lack of fat tissue and the large left hepatic lobe with an optimal acoustic window. The use of high frequency, even linear transducers, usually results in detailed images of all pancreatic areas. A wide spectrum of pancreatic pathologic conditions can be identified and monitored at ultrasound although they are relatively uncommon during childhood compared to the adult. In this paper we briefly review the anatomy, technique, and sonographic aspects of normal and pathological pediatric pancreas.

Specialized Imaging and Procedures in Pediatric Pancreatology: A North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Clinical Report

OBJECTIVES

An increasing number of children are being diagnosed with pancreatitis and other pancreatic abnormalities. Dissemination of the information regarding existing imaging techniques and endoscopic modalities to diagnose and manage pancreatic disorders in children is sorely needed.

METHODS

We conducted a review of the medical literature on the use of the following imaging and procedural modalities in pediatric pancreatology: transabdominal ultrasonography (TUS), computed tomography (CT), magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP), endoscopic ultrasonography (EUS), and endoscopic retrograde cholangiopancreatography (ERCP). Recommendations for current use and future research were identified.

RESULTS

TUS offers noninvasive images of the pancreas but has limitations to details of parenchyma and ductal structures. CT offers improved detail of pancreatic parenchyma, solid masses, and traumatic injuries, but requires relatively high levels of ionizing radiation and does not adequately assess ductal anatomy. MRI/MRCP offers detailed intrinsic tissue assessment and pancreatic ductal characterization, but requires longer image acquisition time and is relatively poor at imaging calcifications. EUS provides excellent evaluation of pancreatic parenchyma and ductal anatomy, but can be subjective and operator dependent and requires sedation or anesthesia. EUS offers the capacity to obtain tissue samples and drain fluid collections and ERCP offers the ability to improve drainage by performing sphincterotomy or placing pancreatic stents across duct injuries and strictures.

CONCLUSIONS

Various imaging modalities may be used in pediatric pancreatology, but TUS and MRI/MRCP are favored. Interventional therapeutic maneuvers primarily involve use of ERCP and EUS. Future research is necessary to optimize equipment, expertise, and appropriate indications.

Pediatric emergency medicine point-of-care ultrasound: summary of the evidence

The utility of point-of-care ultrasound is well supported by the medical literature. Consequently, pediatric emergency medicine providers have embraced this technology in everyday practice. Recently, the American Academy of Pediatrics published a policy statement endorsing the use of point-of-care ultrasound by pediatric emergency medicine providers.  To date, there is no standard guideline for the practice of point-of-care ultrasound for this specialty. This document serves as an initial step in the detailed "how to" and description of individual point-of-care ultrasound examinations.  Pediatric emergency medicine providers should refer to this paper as reference for published research, objectives for learners, and standardized reporting guidelines.

Initial evaluation of hepatic T1 relaxation time as an imaging marker of liver disease associated with autosomal recessive polycystic kidney disease (ARPKD)

Autosomal recessive polycystic kidney disease (ARPKD) is a potentially lethal multi-organ disease affecting both the kidneys and the liver. Unfortunately, there are currently no non-invasive methods to monitor liver disease progression in ARPKD patients, limiting the study of potential therapeutic interventions. Herein, we perform an initial investigation of T1 relaxation time as a potential imaging biomarker to quantitatively assess the two primary pathologic hallmarks of ARPKD liver disease: biliary dilatation and periportal fibrosis in the PCK rat model of ARPKD. T1 relaxation time results were obtained for five PCK rats at 3 months of age using a Look-Locker acquisition on a Bruker BioSpec 7.0 T MRI scanner. Six three-month-old Sprague-Dawley (SD) rats were also scanned as controls. All animals were euthanized after the three-month scans for histological and biochemical assessments of bile duct dilatation and hepatic fibrosis for comparison. PCK rats exhibited significantly increased liver T1 values (mean ± standard deviation = 935 ± 39 ms) compared with age-matched SD control rats (847 ± 26 ms, p = 0.01). One PCK rat exhibited severe cholangitis (mean T1  = 1413 ms), which occurs periodically in ARPKD patients. The observed increase in the in vivo liver T1 relaxation time correlated significantly with three histological and biochemical indicators of biliary dilatation and fibrosis: bile duct area percent (R = 0.85, p = 0.002), periportal fibrosis area percent (R = 0.82, p = 0.004), and hydroxyproline content (R = 0.76, p = 0.01). These results suggest that hepatic T1 relaxation time may provide a sensitive and non-invasive imaging biomarker to monitor ARPKD liver disease.