Hepatic rupture caused by peliosis hepatis.

Peliosis hepatis is a rare entity that can affect children and cause fatal hepatic hemorrhage or hepatic failure. Radiographic findings are nonspecific and can resemble other hepatic pathologies such as cysts, abscesses, metastases, and hemangiomatosis. Peliosis hepatis can resolve spontaneously or by withdrawal of inciting medications. Certain cases may require surgical resection of the involved portions of the liver. Recently, fatal liver hemorrhage was reported in 2 pediatric patients with a rare congenital muscle disorder known as myotubular (centronuclear) myopathy. One of these patients was found at autopsy to have peliosis hepatis. The authors report the first successful treatment of life-threatening liver hemorrhage caused by peliosis hepatis in a child with myotubular myopathy. Awareness of this condition may reduce the catastrophic complications seen with peliosis hepatis.

Imaging of the ductus venosus in neonates: from patency to closure.

OBJECTIVE: To familiarize the radiologist with the variable sonographic appearance of the involuting ductus venosus in neonates. METHODS: Five sick neonates ranging in age from 24 to 42 weeks had abdominal sonographic examinations to check for intra-abdominal diseases. RESULTS: Doppler sonography showed a patent ductus venosus in 3 neonates and a ductus venosus with thrombosis in 2 neonates. The ductus venosus was identified in the liver between the left portal vein and the inferior vena cava. In 2 patients, follow-up sonography showed that the ductus venosus progressively had thrombosis and then disappeared. CONCLUSIONS: The ductus venosus in a neonate has a variable sonographic appearance depending on its stage of involution. Its detection in a sick neonate can lead to inadvertent diagnosis of a hepatic varix, an abscess, or a tumor.

Imaging of primary rhabdomyosarcoma of the diaphragm.

This is a report on a rare case of embryonal rhabdomyosarcoma involving the diaphragm in a 3-year-old boy. This case illustrates the importance of preoperative imaging in the management of this tumor.

Imaging of an unusual case of parasitic twinning.

Conjoined twins are rare in the literature and parasitic conjoined twins are rarer still. To our knowledge no cases of parasitic conjoined twins have previously been reported in the radiology literature. We present a case of parasitic conjoined twins in which radiographic findings played an important role in management.

Hepatic enhancement analysis in children using smart prep monitoring for 2 : 1 pitch helical scanning.

PURPOSE: To analyze hepatic enhancement by using Smart Prep protocols appropriate for children of different weight groups and 2:1 pitch helical CT imaging as the investigative tools. PATIENTS AND METHODS: A group of 55 children ranging in weight between 20 and 180 lbs underwent 67 contrast-enhanced abdominal helical CT examinations using Smart Prep (GE Medical Systems, Milwaukee, Wisc.). Of these studies, 21 (31 %) were excluded because of failure to follow the prescribed Smart Prep protocols. Smart Prep protocols were established for nine different weight groups. Scan delay, aorta and liver time to peak, and liver enhancement over baseline were recorded. RESULTS: Optimal abdominal CT studies with adequate contrast enhancement of hepatic and portal veins were obtained in 46 patients. There was no significant difference in the time between peak aortic and the liver enhancement among different weight groups (mean time 12.0 +/- 7.1 s for all children). However, the mean hepatic enhancement over baseline in children weighing < 30 lbs was below 50 Hounsfield units (HU) compared to the rest of the children who had mean hepatic enhancement of > 50 HU. CONCLUSION: Two-thirds of the Smart Prep protocols were successfully implemented, and all of these resulted in good contrast enhancement of hepatic and portal veins. Optimal mean liver enhancement (> 50 HU) was seen in children >/= 30 lbs. Children < 30 lbs had mean liver enhancement of 33 HU +/- 7.2 above the baseline likely caused by contrast dose.

Resistive indices in the evaluation of infants with obstructive and nonobstructive pyelocaliectasis.

Diagnosing obstructive uropathy by renal resistive indices calculated from duplex Doppler sonographic waveforms has been supported as well as challenged in the radiology literature relating to adults. Despite reports of normally higher resistive indices in children as compared to adults, two studies have documented high sensitivity and specificity of renal Doppler sonography in the diagnosis of obstructive uropathy in children, using the same discriminatory criterion of a resistive index of 0.7 or greater as used in adults. We evaluated 43 infants with significant or bilateral pyelocaliectasis secondary to both obstructive and unobstructive uropathy and found no significant difference in the mean resistive indices or the mean difference in resistive indices of two kidneys in one patient. We conclude that Doppler sonography in infants has no value in differentiating obstructive from nonobstructive pyelocaliectasis.

Neonatal hepatic abscess.

Neonatal liver abscess is a rare entity. There are no published reports of neonatal liver abscess in the radiology literature in the past 15 years. We recently encountered a premature infant in whom a hepatic abscess was diagnosed solely based on abnormal radiographic studies. We report this case to illustrate the unusual clinical and radiographic abnormalities seen with neonatal solitary hepatic abscess.

Sonographic measurements of the neonatal thyroid gland.

The purpose of this study was to establish the normal dimensions of the thyroid gland in euthyroid neonates. Ultrasonographic evaluation of the thyroid gland was performed in the first week of life in 68 term neonates whose gestational ages at birth were 37 to 41 weeks and whose birth weights ranged from 2570 to 4790 g. Measurements of the thyroid lobes were done in transverse, anteroposterior, and longitudinal planes. All neonates had age-appropriate thyroid stimulating hormone levels at birth. Mean +/- 2 standard deviations for thyroid volume were 472 mm3 and 1430 mm3. The mean measurements for the sum of both lobes for transverse, anteroposterior, and longitudinal dimensions were 13.9 mm, 15.1 mm, and 34.6 mm, respectively. No significant correlation of these measurements was found for gestational age, birth weight, or thyroid-stimulating hormone levels. The correlation coefficient between these measurements and total volume was 0.64 or less. Term euthyroid neonates were found to have a thyroid gland volume ranging between 472 mm3 and 1430 mm3. In term neonates sonographic measurements of thyroid lobes should be obtained in all three planes for reliable assessment of thyroid volume.

Evaluation of image quality using 1 : 1 pitch and 1.5 : 1 pitch helical CT in children: a comparative study.

OBJECTIVE: The objective of this study was to compare the quality of 1 : 1 and 1.5 : 1 pitch helical contrast-enhanced thoracic and abdominal CT images in children who cannot cooperate for breath holding. MATERIALS AND METHODS: This is a retrospective study of 33 contrast-enhanced CT examinations in 11 children of 0-4 years of age. All children had an initial CT study using 1 : 1 pitch helical scanning followed over the next 6-36 months by one to four CT examinations with 1.5 : 1 pitch. Radiation dose with the two techniques was measured with a pencil ionization chamber. RESULTS: The two techniques provided comparable overall image quality. There was 33 % less radiation dose with 1.5 : 1 pitch helical scanning. CONCLUSION: The 1.5 : 1 pitch helical CT provides comparable quality images and a smaller radiation dose than 1 : 1 pitch in examining children aged 0-4 years.

Longitudinal tibial stress fracture.

Fatigue-type stress fractures occur following repetitive loading of normal bone. These occur frequently in the tibia, although vertical orientation to the fracture is much less common than transverse orientation. Without a convincing history of new or accelerated muscular activity, imaging can be difficult to interpret and evaluation may require more than one imaging modality to exclude other diagnostic considerations, including neoplasm and osteomyelitis.

Congenital and acquired lung hernias.

Lung hernia is defined as a protrusion of lung parenchyma beyond the confines of the musculoskeletal thorax. Lung hernias can be classified according to location (i.e., cervical, thoracic, or diaphragmatic) and etiology. Approximately 80% of reported cases of lung hernia are acquired, usually related to trauma or surgery. Symptoms are few, infrequent, and vague. A painless, local, and inconstant bulging is evident on physical examination. The diagnosis of a lung herniation is accomplished using chest radiographs in the most cases. Surgery is usually reserved for large hernias or incarcerated hernias.

Chloral hydrate sedation of children undergoing CT and MR imaging: safety as judged by American Academy of Pediatrics guidelines.

OBJECTIVE: The purpose of this prospective study was to determine the frequency of adverse events associated with supplemented and unsupplemented chloral hydrate sedation in a select group of children undergoing CT or MR imaging using the revised American Academy of Pediatrics (AAP) monitoring and management guidelines for pediatric sedation. The AAP guidelines do not recommend drug selection or dosages but define patient selection, discharge criteria, and monitoring standards for sedating children. SUBJECTS AND METHODS: This prospective study included 410 children 4 years of age or younger who were scheduled for CT and MR imaging as outpatients. Selected children were physical status 1 or 2 as determined by the American Society of Anesthesiologists physical status classification and had no contraindications to sedation per our institutional sedation policy. Children younger than 1 year old received only oral incremental doses of chloral hydrate. Children 1-4 years old received hydroxyzine plus incremental doses of chloral hydrate. Children between 2 and 4 years old who were not satisfactorily sedated 30 min after hydroxyzine plus incremental chloral hydrate were given 2 mg/kg meperidine intramuscularly, with a maximum dose of 50 mg. All children were monitored according to the revised guidelines recommended by the committee on drugs of the AAP. Vital signs and arterial hemoglobin oxygen saturation (SpO2) were monitored continuously by registered nurses trained in pediatric advanced life support from the time of sedative drug administration until the recommended discharge criteria were met. RESULTS: Mild hypoxia (SpO2, 90-95%) that resolved spontaneously without any therapeutic intervention was seen in 9% of the chloral hydrate group and in 5% of the chloral hydrate-hydroxyzine group. One child in the chloral hydrate group had severe hypoxia (SpO2, 85-89%), and one child in the chloral hydrate-hydroxyzine group had moderate hypoxia (SpO2, < 85%). Both required therapeutic intervention. In both cases, the severity of the underlying medical disease was underestimated at the time of presedation medical screening. The success rate of sedation was 100% for all the children having CT. For those having MR imaging, success was 100% for children 1-4 years old and 97% for children less than 1 year old. CONCLUSION: Use of supplemented and unsupplemented chloral hydrate sedation provides effective and safe sedation in children if the AAP guidelines for patient selection, monitoring, and management are followed. Careful medical screening and patient selection by knowledgeable medical personnel is important to exclude patients at high risk for life-threatening hypoxia. Monitoring with AAP guidelines is essential for prompt detection and management of life-threatening hypoxia.

Periportal tracking in pediatric blunt abdominal trauma. Correlation with liver enzymes and liver injury.

This is a retrospective study of the computed tomography (CT) examinations and medical records of 243 consecutive pediatric patients sent for CT studies after blunt abdominal trauma. The purpose of the study was to determine the frequency and significance of periportal tracking identified by CT, and correlate this finding with liver enzyme levels and liver injury. Periportal tracking (PPT) was divided into four grades (0-3) depending upon the distribution of decreased attenuation adjacent to the portal vessels. Circumferential PPT extending to the periphery of the liver (grade 3) was found in 20/243 children. They had a higher incidence of liver parenchymal injury seen on CT 20% versus 0.5% in combined PPT grades 0-2. Sixteen children with grade 3 PPT and no liver injury had significantly elevated liver enzymes as compared to children with combined 0-2 grade PPT. Eleven of the 20 children with grade 3 PPT had no other CT evidence of intraabdominal injury and none of these patients developed intraabdominal hemorrhage. Thus, grade 3 periportal tracking as an isolated abnormality did not indicate a clinically significant liver injury in any patient.

Thymopharyngeal duct cyst: MR imaging of a third branchial arch anomaly in a neonate.

Third branchial arch anomalies are rare. The authors present a case report of a neonate with a rapidly growing neck mass due to cystic dilation of a persistent thymopharyngeal duct, which is a derivative of the third branchial arch. The presence of thyroid and thymic tissue in the cyst wall, the communication of the cyst with the piriform sinus, and the relationship of the cyst to carotid vessels and the sternomastoid muscle were consistent with the features of a thymopharyngeal duct cyst embedded in the thyroid gland.