The use of hepatocyte extraction fraction to evaluate neonatal cholestasis.

PURPOSE: Hepatobiliary scintigraphy is used routinely to evaluate infants with neonatal cholestasis. Hepatobiliary scintigraphy determines biliary patency by detecting radioactivity in the bowel on imaging, in duodenal and gastric aspirates, or all of these. During hepatobiliary scintigraphy, the hepatocyte extraction fraction (HEF) is calculated by deconvolution analysis. Normal values of HEF are more than 90%. It is believed that HEF may predict hepatic dysfunction, because, during hepatobiliary scintigraphy, the radiopharmaceutical used in this test is extracted by the hepatocytes from the blood stream. Therefore, a low value of HEF is seen with more severe hepatocellular disease. The goal of this study was to determine whether HEF has any correlation with synthetic liver function, whether HEF can differentiate obstructive from nonobstructive lesions that cause neonatal cholestasis, and whether HEF can predict the outcome of the different causes of neonatal cholestasis. METHODS: A retrospective analysis of 68 hepatobiliary scintigraphy results was done in patients with neonatal cholestasis for a period covering 6 years. RESULTS: The HEF was available in 67 of these 68 patients, with a median value of 25% (range, 3.3% to 100%). The results of synthetic liver function tests (i.e., albumin and prothrombin time) were normal in all infants with neonatal cholestasis. No significant correlation was detected between HEF and the serum levels of total and direct bilirubin, albumin, alkaline phosphatase, and prothrombin time by exploratory data analysis (R = 0.08; small, P > 0.2). The HEF values in different causes of neonatal cholestasis were compared: extrahepatic biliary atresia, neonatal hepatitis, and a miscellaneous category consisting of alpha1-antitrypsin deficiency, ischemic hepatitis, paucity of bile ducts, and others. The outcomes of these diseases were assessed as resolution, continuing disease, transplantation, or death, but no predictive correlation was found with HEF. CONCLUSIONS: A single determination of HEF is of no value in assessing synthetic liver function (as assessed by albumin and prothrombin time), specific diagnoses, and outcomes in patients with neonatal cholestasis. Therefore, a low isolated value of HEF should not be considered suggestive of poor prognosis and outcome in these patients.

Pediatric musculoskeletal computed radiography.

BACKGROUND: In conventional radiography, a film-screen system serves as the X-ray detector and the film also functions as an archival and display medium. Unlike film-screen radiography, these functions are uncoupled in computed radiography (CR). CR uses conventional radiographic equipment to expose an image on a storage phosphor plate instead of a film-screen combination. OBJECTIVE: To review the basic concepts of CR and to provide a background for discussion of specific musculoskeletal applications of CR in children. MATERIALS AND METHODS: Various aspects of musculoskeletal CR in children are presented based on our 4 years' experience and a review of the literature. RESULTS: A greater amount of scatter capture occurs with storage phosphor CR than with a film-screen system in the 70- to 120-kVp range. This is attributed to a lower K-absorption edge of barium in the barium fluorohalide (BaFBr) compound used in the imaging plate. A significant reduction of scatter to primary radiation, improvement in bony trabecular sharpness, and improvement in line pair resolution can be achieved in pediatric musculoskeletal imaging using an air gap without an increase in the skin entrance dose as compared to the non-grid table top technique. With CR, in addition to proper radiographic exposure technique, one needs to preprogram and select the optimal processing technique for each anatomic region, projection and age group of the child. CONCLUSION: The main advantages of CR in pediatric musculoskeletal imaging consist of a reduction in radiation dose for many applications, improved contrast resolution, near elimination of repeat radiographs related to exposure errors, and digital processing capabilities for image enhancement, storage, retrieval, display and transmission. The current limitations of CR include the moderately high start-up cost, the long learning curve to produce optimal films, and the reduced spatial resolution.

Musculoskeletal computed radiography in children: scatter reduction and improvement in bony trabecular sharpness using air gap placement of the imaging plate.

The effect of various air gaps on computed radiographic musculoskeletal images was investigated using a knee phantom. Scatter to primary radiation ratios were measured using the beam stop method at air gaps ranging from 0 to 30 in. (0-762-mm). Bony trabecular sharpness, line pair resolution, quantum mottle and visualization of low-contrast beads in the soft tissues were evaluated. A significant reduction of scatter to primary radiation ratio, from a value of almost 1 at table top to about 0.4 at 10-in. (254-mm) air gap and about 0.2 at 25-in. (635-mm) air gap placement of the computed radiography (CR) imaging plate, was obtained. A progressive improvement in bony trabecular sharpness and line pair resolution, compared with the table top and Bucky images was observed on 10-in. (254-mm) through 25-in. (635-mm) air gap images. Sharpness of the bony trabeculae and line pair resolution were best on the 25-in. (635-mm) air gap images. The skin entrance radiation dose does not have to be increased for air gap digital radiography. The radiographic noise or quantum mottle is highest on the Bucky image, higher on air gap images and minimal on the table top images, despite a high scatter to primary radiation ratio at the table top. The lower quantum mottle on the table top images allowed for maximal visualization of low contrast densities in the soft tissues. Air gap radiography further improves musculoskeletal computed imaging by reducing the scatter to primary radiation ratio without an increase in the skin entrance dose. For significant reduction of the scatter to primary radiation ratio and best evaluation of line pair spatial resolution and bony trabeculae, a 25-in. (635-mm) air gap with digital radiography would be optimal. For evaluation of low contrast densities in the soft tissues, table top placement would be the technique of choice.

Brain imaging during seizure: ictal brain SPECT.

The role of single photon computed tomography (SPECT) in presurgical localization of medically intractable complex partial epilepsy (CPE) in children is reviewed. 99mTechnetium Neurolite, a newer lipophylic agent with a high first pass brain extraction and little or no redistribution is injected during a seizure, while the child is monitored with a video recording and continuous EEG and SPECT imaging is performed in the next 1-3 hours with the images representing regional cerebral profusion at the time of injection. On SPECT studies performed with radiopharmaceutical injected during a seizure, ictal focus is generally hypervascular. Other findings on ictal brain SPECT include hypoperfusion of adjacent cerebral cortex and white matter, hyperperfusion of contralateral motor cortex, hyperperfusion of ipsilateral basal ganglia and thalamus, brain stem and contralateral cerebellum. Ictal brain SPECT is non-invasive, cost effective and highly sensitive for localization of epileptic focus in patients with intractable CPE.

Pediatric air-gap chest digital imaging: an experimental study.

Geometrically magnified computed radiography (CR) chest radiographs can be obtained in children using the same techniques as for non-grid, non-magnified CR radiographs. The resulting magnification images have less scatter than grid images and better line pair resolution.

Brain sonography, computed tomography, and single-photon emission computed tomography in term neonates with perinatal asphyxia.

The clinical diagnosis of hypoxic-ischemic brain injury in neonates can be supported by radiologic studies including cranial sonography, computed tomography (CT), single-photon emission computed tomography (SPECT), magnetic resonance imaging, and positron emission tomography. The role of cranial sonography, CT, and SPECT in term neonates with perinatal asphyxia is reviewed in this article.

Neonatal skull depression: review of four cases.

Neonatal skull depressions may occur from traumatic delivery or abnormal intrauterine position. Surgery has been recommended when the condition is thought to threaten neurologic development; however, normal neurologic outcomes have been observed in conservatively managed infants. A review of four patients with neonatal skull depression is presented together with the obstetric history and findings from nursery examinations, skull roentgenograms, electroencephalograms, and follow-up pediatric visits. Two patients underwent surgical elevation of the depression, while two children with depressions of similar severity were managed without intervention. Neurologic and cosmetic outcomes have been normal in all four patients. It is suggested that uncomplicated depressions should be treated conservatively, with surgical elevation reserved for neonates with intracranial complications.

The enthesopathic changes of hypophosphatemic osteomalacia in adults: radiologic findings.

The enthesopathy (bone proliferation at sites of ligament, tendon, joint capsule, and interosseous membrane attachment) that may be present in adults who have longstanding hypophosphatemic osteomalacia, the most common type of osteomalacia, has received little attention in the radiologic literature. These proliferative enthetic changes may be associated with various musculoskeletal symptoms. The spectrum of proliferative enthesopathic changes, involving the axial and appendicular skeleton, is described in six patients 18-63 years old. Proliferative changes at the attachment of the annulus fibrosus were present in six of six patients and ranged in extent from tiny hyperostoses at a few levels to thin marginal symmetric syndesmophytes involving the entire lumbosacral spine and mimicking spondylitis. Thoracic spinal syndesmophytes were present in four patients and cervical hyperostoses of various magnitudes were present in three patients. Changes in the sacroiliac joints were present in four of six patients and varied from mild widening to symmetric intraarticular and anterior paraarticular bony bridging. Proliferative enthesopathy involving the pelvis and proximal femora was present in six of six patients. Appendicular changes included accessory ossicles within the wrist and hands and bony proliferation of the distal radius and metacarpal heads. These were noted in four patients. Ossification of the interosseous membrane of the forearms or the lower extremities was present in six patients and paraarticular bony proliferation about the elbows was noted in four patients. It is apparent that the severity of the enthesopathy that occurs may vary, and that hypophosphatemic osteomalacia should be recognized as a cause of enthesopathy even if other radiographic findings of osteomalacia may not be present on available radiographs.

Anterior dislocation of the shoulders with bilateral brachial plexus injury.

A case of bilateral anterior shoulder dislocation accompanied by bilateral brachial plexus injuries is presented. A 53-year-old man fell and landed on his chest and arms flexed at the elbows. The dislocations were satisfactorily reduced using the forward elevation, flexion maneuver. Electromyography and nerve conduction studies confirmed bilateral brachial plexus lesions. Arthrogram of the right shoulder demonstrated a rotator cuff tear. The patient is undergoing physical therapy and making a slow recovery.

Diaphyseal bone disease: scintigraphic-radiographic correlation.

Though generally nonspecific, the patterns of diaphyseal uptake of bone seeking radionuclides, when correlated with the radiographic findings and clinical histories, often suggest specific diagnoses and may obviate the need for further imaging. Diaphyseal uptake is considered in terms of "hot spots," unilateral long segment lesions and bilateral processes that may be symmetric or asymmetric in distribution. Scintigrams and corresponding radiographs of 18 different lesions are illustrated.

Acute recurrent appendicitis with appendicolith.

Appendiceal disease can be acute, acute recurrent, or chronic. Acute appendicitis is the most common form. Acute recurrent appendicitis is more common than chronic appendicitis. In children the clinical manifestations of appendicitis are variable. Patients who have an appendicolith usually develop appendicitis, often with perforation. A case is presented of 3-year follow-up of a patient with an appendicolith and acute recurrent appendicitis. The literature about appendicoliths is reviewed. In the appropriate clinical setting, a history of prior episodes of similar right lower quadrant pain does not preclude the diagnosis of appendiceal disease. Awareness of the less common forms of appendicitis is important so that appropriate treatment is not delayed.

Ribbing's disease: radiographic-scintigraphic correlation and comparative analysis with Engelmann's disease.

Engelmann's disease is an uncommon condition characterized radiographically by symmetric diaphyseal sclerosis involving predominantly the tubular bones. Ribbing described an entity with similar but less extensive or severe changes which he thought differed sufficiently to constitute a distinct process. We present two cases of Ribbing's disease and one of Engelmann's disease, emphasizing the differences between the two. Radiographic-scintigraphic correlation is provided to demonstrate the value of skeletal scintigraphy in cases of Ribbing's disease and progressive diaphyseal dysplasia.

Thanatophoric dysplasia and cloverleaf skull.

Nine infants with thanatophoric dysplasia (TD) and cloverleaf skull (CS) are reported. Twenty-two previously published CSTD cases are reviewed. These CSTD cases are compared to cases of TD without CS. It is concluded that there are two types of TD: type 1, with curved femora and very flat vertebral bodies; and type 2, with straight femora and taller vertebral bodies. Consistent but subtle histopathological characteristics differentiate the two types. Only a very few type 1 cases have CS, and the CS is mild. Almost all type 2 cases have severe CS.

Acute plastic bowing fractures in children.

We report the cases of two children with acute plastic fractures of the long bones following trauma. Bowing deformity was evident clinically and radiographically in both cases. The unique radiologic features consisted of absence of fracture lines and of periosteal new bone formation during the healing phase. The mechanism of injury as well as possible complications in management of acute plastic bowing fractures are discussed.

Metabolic bone disease in pseudohypoparathyroidism: radiologic features.

We reviewed the radiographs of six patients with pseudohypoparathyroidism (PHP) manifested by variable renal and skeletal resistance to parathyroid hormone (PTH). Features compatible with hyperparathyroid bone disease, osteomalacia, and rickets were observed. Skeletal changes of hyperparathyroidism included (a) subperiosteal bone resorption, (b) radiolucent lesions, caused by either brown tumors or bone cysts, (c) slipped capital femoral epiphyses, (d) focal areas of osteosclerosis, (e) periosteal neostosis, and (f) osteopenia with reduced cortical and trabecular bone volume. Histologic bone features were compatible with osteitis fibrosa in all patients, which suggests that the skeleton responded to the bone-remodeling effects of PTH despite hormonal resistance at other target sites. Skeletal changes of rickets included metaphyseal irregularities, cupping, and widening of the growth plates. Osteomalacia was indicated by Looser zones in one patient and confirmed by histologic evidence in three patients.