Cost-effective imaging approach to the nonbilious vomiting infant.

OBJECTIVE: To develop a cost- and time-effective algorithm for differentiating hypertrophic pyloric stenosis (HPS) from other medical causes of emesis in infants referred from community-based pediatricians and family practitioners to the imaging department of a tertiary children's care facility. METHODS: Eighty-nine vomiting infants (22 females, 67 males) between the ages of 11 and 120 days (mean, 43.5 days) had received nothing by mouth for at least 1 hour before the study. Each child was assessed for duration of vomiting, status of body weight, time and volume of last ingestion, and time of last emesis. A #8 French (Sherwood Medical, St Louis, MO) nasogastric feeding tube was placed in the child's stomach. The contents were aspirated and measured to determine likelihood of HPS. An aspirated volume >/=5 mL implicated gastric outlet obstruction, and ultrasonography (US) was performed. If this study was positive for HPS, the patient was referred for surgery. If US was negative, an upper gastrointestinal series (UGI) was performed. An aspirated stomach contents volume <5 mL suggested a medical cause for the emesis, and UGI was performed. Pediatric surgeons with no knowledge of the volume results palpated the abdomens of 73 of 89 infants (82%). RESULTS: Twenty-three of 89 patients (25%) had HPS. The aspirate criteria for HPS had a sensitivity of 91%, a specificity of 88%, and an accuracy of 89%. Of the false-positive studies (total = 8), six were related to recent significant ingestion (within 2 hours of the study), and two were attributable to antral dysmotility. The surgeons palpated the mass in 10 of 19 patients (53%). Sensitivity and specificity were 53% and 93%, respectively. Only 6 of 89 infants (7%) required both US and UGI to determine the etiology of the nonbilious vomiting. By performing the UGI in 66 patients, it was also found that 14% had slow gastric emptying and 79% had gastroesophageal reflux. Eighty-one percent of the gastroesophageal reflux was significant. CONCLUSION: The volumetric method of determining the proper imaging study is cost- and time-effective in the evaluation of the nonbilious vomiting infant for pyloric stenosis. If US was performed initially in all patients referred for imaging, two studies would have been performed in 68 of 89 patients (76%) to define the etiology of the emesis. Because we used the volumetric method, 62 fewer imaging studies were performed, representing a savings of $4464 and 30 hours of physician time. If children are given nothing by mouth for 3 to 4 hours before gastric aspiration, the specificity of the volumetric method improves to 94%, and the accuracy improves to 96%.

MR imaging findings in children with merosin-deficient congenital muscular dystrophy.

BACKGROUND AND PURPOSE: Our purpose was to determine the brain MR imaging characteristics of merosin-deficient congenital muscular dystrophy in children. METHODS: We reviewed the MR imaging findings of the brain in three children with known merosin-deficient congenital muscular dystrophy to determine the presence of any cerebral or cerebellar abnormalities of development or abnormalities of the white matter. RESULTS: In all three patients, there was normal formation of the cerebrum, the cerebellum, and no evidence of neuronal migration anomalies. All three patients had abnormal white matter in the cerebrum, with sparing of the corpus callosum, internal capsule, cerebellum, and brain stem. CONCLUSION: MR imaging of the brain in children with merosin-deficient congenital muscular dystrophy reveals a consistent pattern of white matter abnormality. We postulate that disruption of the blood-brain barrier associated with merosin deficiency leads to increased water content, resulting in abnormal white matter signal intensity.

Age of closure of the neurocentral cartilage in the thoracic spine.

We reviewed magnetic resonance images (MRIs) of 91 patients to estimate the chronologic age of closure of the neurocentral cartilage in the thoracic spine. The neurocentral cartilage on MRI appeared low signal in both T1- and T2-weighted images. It was thick and clearly identified in younger patients but was thin and vague in older patients. The neurocentral cartilage closed at 11-16 years in female patients and at 12-16 years in male patients.

The natural history of Klippel-Feil syndrome: clinical, roentgenographic, and magnetic resonance imaging findings at adulthood.

Twenty-two patients (15 women and seven men) with Klippel-Feil syndrome were reviewed at an average age of 35 years (range, 26-57 years). The average age at diagnosis was 9 years (range, birth-32 years). All patients had a clinical neurologic and orthopaedic examination. Ten patients (45%) had abnormal findings on clinical examination, and 15 patients (68%) had at least one complaint that could be related to the syndrome. The roentgenograms were unremarkable in all patients, except for the typical findings of congenital fusion; no vertebral subluxation or stenosis was noted in any patient. The magnetic resonance images revealed degenerative changes in the disks of 100% of the patients, evidenced by a low-intensity signal on the T2-weighted images. Nineteen patients (86%) had abnormal findings on the magnetic resonance imaging scans, including disk protrusion (16 patients), osteophytes (four patients), syringomyelia (four patients), and narrowing at the level of the craniovertebral junction (six patients). Our results confirm the well-held belief that the Klippel-Feil syndrome can cause problems in adult life.

Ultrasonographic features of gastrointestinal duplications.

The variable sonographic appearance of duplication cysts is presented. Eighteen sonograms from 14 patients, aged 1 day to 8 years, were reviewed over an 8 year period. Water and other aqueous contrast agents were used in six patients as part of the sonographic evaluation. All lesions were confirmed by surgery. All but two patients were symptomatic. Twenty-four cysts were detected, ranging in size from 1.7 to 15.5 cm. The duplication cysts revealed a spectrum of sonographic findings (cystic to solid appearing masses). The mass characteristics, including the "muscular rim sign," and internal debris or hemorrhage, were demonstrated. Multiple unsuspected cysts (3 of 14 or 20%) and complications such as perforation were readily seen with ultrasonography. Serial sonograms demonstrated the changing morphology of two cysts. Other unsuspected intra-abdominal and pelvic pathologic conditions, including pyloric stenosis and ovarian cysts, were identified. Identification of the muscular rim sign is the most reliable indication of a duplication cyst. Multiple masses as well as possible accompanying anomalies in the abdomen and pelvis are readily evaluated with sonography. Lesions are easily followed with serial studies if there is no surgical intervention.

Evaluation of physeal behavior in response to epiphyseodesis with the use of serial magnetic resonance imaging.

The stages in the closure of the growth plate after percutaneous epiphyseodesis were studied in fourteen patients (eight girls and six boys) with coronal T1-weighted spin-echo images and coronal field-echo images of the knee. A total of thirty-three magnetic-resonance imaging studies of the knee were made the first week, the fourth month, the eighth month, or one year after the epiphyseodesis. A mature bridge of bone was seen at the operative sites approximately eight months after the operation. In the central undisturbed area between the operative sites, there was a progressive decrease in the width of the physeal cartilage that remained visible eight months after the operation. Growth recovery lines were not seen postoperatively in any patient, and the physis closed in all of the patients. The physis of the adjacent untreated bone served as a control bone and showed neither a change in width nor any growth recovery lines. Magnetic resonance-imaging studies provide excellent visualization of the anatomical changes that lead to closure of the physis after an epiphyseodesis, and we believe that these studies provide a method of assessment of the physis after an injury.

Dysplasia epiphysealis hemimelica: diagnosis and treatment.

Clinical features and radiographic findings of eight patients with dysplasia epiphysealis hemimelica are described. In all patients, a single lower extremity was involved. The most common sites of involvement were the distal tibia and the distal femur. Magnetic resonance imaging was beneficial in determining a plane of separation between the accessory ossification center and the normal epiphysis. If the lesion is extraarticular, simple excision of the mass yields favorable results. If the lesion is intraarticular, an osteotomy may be needed to correct an angular deformity. Recurrence of the deformity is common.

Protrusio acetabuli in neurofibromatosis: nondysplastic and dysplastic forms.

Protrusio acetabuli (PA) in neurofibromatosis is not well documented in the literature. Two forms of PA, a nondysplastic and dysplastic type, are noted. Twenty-one percent of hips (13 patients) in neurofibromatosis were found to have some form of acetabular protrusion abnormality. In the control group (83 patients) without stigmata of neurofibromatosis, only 9% of hips were associated with PA. The progressive dysplastic form of PA is usually associated with contiguous soft-tissue neurofibromas and lumbar dural ectasia. The nondysplastic, nonprogressive form has less of an association with regional soft-tissue abnormalities and almost no association with dural dysplasia.

Growth plate of the normal knee: evaluation with MR imaging.

The purpose of this study was to establish the characteristics at magnetic resonance (MR) imaging of the normal physis of the tibia and of the fibula during development and maturation. Sixty MR imaging studies of the knee were performed in male and female subjects aged 1-20 years who had no clinical symptoms or radiographic abnormality in the lower extremity. Images obtained with both T1-weighted and field-echo pulse sequences were reviewed to establish developmental characteristics of the distal femoral and proximal tibial growth plates. Four stages of physeal development were identified. A field-echo pulse sequence with repetition time of 700 msec, echo time of 20 msec, and a flip angle of 40 degrees best depicted growth-plate cartilage. Some coronal and sagittal images of the normal knee show discontinuity of the physeal cartilage (drop-out sign), which should not be mistaken for premature closure.

Use of computed tomography, magnetic resonance imaging, and localized 1H magnetic resonance spectroscopy in Canavan's disease: a case report.

The neuroradiological evaluation of Canavan's disease in a 38-month-old girl is discussed. Computed tomography showed diffuse symmetrical low attenuation values of the subcortical and deep cerebral white matter. Magnetic resonance imaging demonstrated symmetrical diffuse low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. With the use of 1H magnetic resonance spectroscopy, we were able to show elevated levels of N-acetylaspartic acid in the occipital lobe of our patient. The in vivo measurement of N-acetylaspartic acid in the brain by 1H magnetic resonance spectroscopy offers an additional noninvasive diagnostic test for establishing the diagnosis of Canavan's disease. With the increasing availability of magnetic resonance spectroscopy, clinicians may be able to confirm the diagnosis of Canavan's disease immediately after magnetic resonance imaging reveals the typical abnormalities of the white matter.

Intraspinal epidermoid tumors in children: problems in recognition and imaging techniques for diagnosis.

Iatrogenic intraspinal epidermoid tumors are very rare. The similarity of the clinical manifestations of the tumor with other childhood problems can pose a problem in diagnosis. In addition, because of the lag in time between the lumbar puncture and the development of a symptomatic tumor, this relationship is overlooked and can cause a delay in diagnosis, as in the present report of four children. Magnetic resonance imaging was found to be superior to myelography in defining the tumor and its relationship to other structures inside the dural sac. All patients underwent surgical excision, with subsequent resolution of symptoms.

Aneurysmal bone cyst of the spine in children. MRI imaging at 0.5 tesla.

Two patients with aneurysmal bone cysts of the spine demonstrate striking similarities when examined with magnetic resonance imaging (MRI), while the plain radiographs and images on computed tomography (CT) are quite different. Gadolinium DTPA enhanced T1W images were especially helpful in the definition of the lesion by showing enhancement of the septations of the aneurysmal bone cysts. The septations represent the fibrous walls inherent to these lesions.

Computed tomography in the diagnosis of lymphangiomas in infants and children.

The computed tomographic features in 14 children (age range = 2 days to 10 years) with cystic hygromas of the neck and lymphangiomas of the chest, abdomen, and extremities were studied. Computed tomography can determine the morphology of these masses, their exact locations and their relationship to other organs. Most lymphangiomas appear as cystic masses of low attenuation value with or without septations. The septations may be thin or thick and result in a conglomerate of cysts of irregular borders, varying in size from a few millimeters to several centimeters. Some of the septae show enhancement after a bolus injection of contrast material. Contrary to what has been reported, lymphangiomas may invade nearby tissues and organs.

Magnetic resonance imaging and computed tomography in Pelizaeus-Merzbacher disease.

Six patients with the classical form of Pelizaeus-Merzbacher disease (PMD) were studied with computed tomography (CT) and magnetic resonance imaging (MRI) of the brain. While final diagnosis of PMD should be made on the basis of histopathologic findings in the brain, findings in this group support the fact that MRI can be used for tentative early diagnosis when computer tomographic examination is normal or nondiagnostic. All patients had MRI findings reflecting a pattern of diffuse white matter disease that can be considered characteristic in the appropriate clinical setting.

Plastic bowing of the ribs in children.

Four cases of plastic bowing of the ribs are presented. In three patients with Werdnig-Hoffman disease, plastic curvatures were associated with chronic pneumonia and atelectasis. We postulate that intrapulmonary retractive forces can deform ribs thinned by muscular atrophy. In turn, thoracic collapse can perpetuate lobar and segmental atelectasis. In one case of osteogenesis imperfecta without pneumonia, we believe normal muscle forces bent ribs weakened by deficiency of normal cortical architecture.

Computed tomography in the evaluation of tubo-ovarian abscesses in children.

There are many reports in the literature describing ultrasonic features of tubo-ovarian abscess. Computed tomography characteristics of these lesions are less frequently described. This presentation shares our experience with computed tomography findings in two girls, aged 6 and 14 years, with tubo-ovarian abscesses.