Absent uptake on hepatobiliary scintigraphy in hepatic lobar infarction from portal vein occlusion in cholangiocarcinoma.

Hepatic infarction is an uncommon entity because of the dual blood supply to the liver. We report a case in which multimodalities demonstrate infarction of the left lobe of the liver secondary to left portal vein occlusion by an invasive cholangiocarcinoma. A 99mTc-DISIDA hepatobiliary scan showed complete absence of activity to the left of the gallbladder fossa. The differential diagnosis of absent hepatic activity on a hepatobiliary scan must include hepatic infarction.

Pediatric hepatic imaging.

Common indications for liver imaging in children include trauma, suspected mass, pre-liver transplantation, monitoring after liver transplantation, jaundice, or liver dysfunction. This article highlights areas where the pathology or imaging approach in children differs from that seen in adults. Topics covered include imaging of a suspected hepatic mass, neonatal jaundice, and segmented liver transplantation.

Imaging of congenital vascular and lymphatic anomalies of the head and neck.

Congenital lymphatic and vascular malformations and infantile hemangiomas can be combined under the heading of endothelial malformations. Based on their biologic behavior, endothelial malformations can be divided into two groups: infantile hemangiomas and vascular malformations. Vascular malformations can be subdivided into lymphatic, capillary, venous, and arteriovenous malformations. Often frightening for the patient and the patient's family, some endothelial malformations, however, will resolve; yet others can lead to long-term disfigurement and even can be fatal-due to airway obstruction, secondary infection, or exsanguination. When recognized early, however, the appropriate therapy, or watchful waiting, can be initiated, and the long-term physical and psychological consequences of these malformations can be minimized.

MR imaging of mediastinal masses.

Although ongoing developments in MR imaging have resulted in improved image quality and decreased acquisition time, MR imaging is largely used as an adjunct to CT scanning in the evaluation of mediastinal abnormalities. In this role, MR imaging often provides additional information about the nature, location, and extent of disease. MR imaging is useful in confirming the cystic nature of mediastinal lesions that appear solid on CT and, by revealing small amounts of intralesional fat, can suggest the diagnosis of hemangioma, teratoma, or extramedullary hematopoesis. MR imaging is the preferred modality for imaging neurogenic tumors, because its multiplanar capability and high contrast resolution can best demonstrate the number and nature of the lesions (differentiating cysts from neoplasms), intraspinal extension, and craniocaudad extent. MR imaging is also especially useful for evaluating the mediastinum of patients for whom the administration of iodinated contrast material is contraindicated.

Novel techniques for MR imaging of pulmonary airspaces.

Hyperpolarized gas- and molecular oxygen-enhanced MR imaging are two new techniques for high-resolution MR imaging of pulmonary airspaces. Both techniques produce excellent images in a safe, reproducible, and technically feasible manner. Because morphologic and functional information is obtained, and radiation is not used, these techniques may prove ideal for serially evaluating patients with a variety of lung diseases that affect pulmonary ventilation, such as cystic fibrosis, emphysema, asthma, or bronchiolitis obliterans syndrome in lung transplant recipients. At present, the greatest clinical experience is with hyperpolarized He-3-enhanced MR imaging. This technique is limited, however, by the limited availability of He-3, by its polarization requirements, and by the need to tune the MR system to the resonant frequency of the gas. There is less clinical experience with oxygen-enhanced MR imaging. Although this technique produces images with more inherent noise than hyperpolarized He-3 imaging, this problem can be overcome by signal averaging. Oxygen-enhanced imaging has the major advantages of lower cost and ready availability. For oxygen-enhanced imaging, the MR imaging system does not need to be readjusted; imaging is performed at the conventional hydrogen proton frequency.

Utility of radiographs in the evaluation of pediatric upper airway obstruction.

The evaluation of children with airway obstruction always involves a history and physical examination. The definitive diagnosis is most often made with microlaryngoscopy and bronchoscopy (MLB), and in cases of extrinsic compression, information is gained from magnetic resonance imaging. Although plain radiographs of the airway are often used as a primary diagnostic modality in children with airway obstruction, the accuracy of plain radiographs in predicting specific airway abnormalities has not previously been evaluated. This study was designed to correlate the findings of plain airway radiographs with the diagnosis made at the time of MLB. Medical records from 1991 to 1996 were reviewed to identify patients that had MLB and airway radiographs within 2 days of one another. One hundred forty-four cases were identified and divided into diagnostic categories. Statistical analysis showed a high sensitivity (>86%) for the accuracy of the radiologic diagnoses of exudative tracheitis, airway foreign body, and innominate artery compression. Laryngomalacia and tracheomalacia had a much lower sensitivity (5% and 62%, respectively). We believe that plain radiographic evaluation of the airway provides important information to the diagnostician. However, plain radiographs can be inaccurate and must be considered along with a history, physical examination, and clinical suspicion. Microlaryngoscopy and bronchoscopy remains the ultimate diagnostic test for airway disorders.

Maximizing the usefulness of imaging in children with community-acquired pneumonia.

In summary, imaging plays important roles in the diagnosis and treatment of children with community-acquired pneumonia. These roles include confirmation or exclusion of pneumonia, differentiation between viral and bacterial pneumonia, exclusion of other causes of symptoms, evaluation when the pneumonia fails to resolve, and evaluation of related complications.

Unilateral abdominal wall hypoplasia: radiographic findings in two infant girls.

Prune belly syndrome (PBS) is defined as an association of abdominal wall deficiency, genitourinary anomalies, and, in males, cryptorchism. Although PBS is more common in males, females can also have the condition. In both sexes, expression of the disease is often incomplete and prognosis depends upon the specific abnormalities present. PBS in girls or incomplete expression of PBS is called pseudoprune belly syndrome (PPBS). We recently evaluated two baby girls with PPBS. Both girls had unilateral abdominal wall hypoplasia associated with cardiac, genitourinary, gastrointestinal, pulmonary, and musculoskeletal involvement that ranged from normal to severe. One of the patients also demonstrated congenital cytomegalovirus (CMV) infection and focal jejunal hypoganglionosis. Since CMV has been associated with both aganglionosis and PBS, it is possible that CMV induced both conditions in this patient.

CT appearance of parapneumonic effusions in children: findings are not specific for empyema.

OBJECTIVE: Although definitive differentiation of empyema from transudative parapneumonic effusion is based on the analysis of pleural fluid, certain CT findings have been described as highly suggestive of empyema. This study compares the CT findings of parapneumonic effusions with the results of thoracentesis, thoracoscopy, or both to determine whether these CT findings can reliably differentiate empyemas from transudative parapneumonic effusions in children. MATERIALS AND METHODS: CT scans obtained to evaluate pleural or parenchymal complications of pneumonia were reviewed. Parapneumonic effusions were evaluated for the CT findings of pleural enhancement; parietal pleural thickening; thickening, increased attenuation, or both of the extrapleural subcostal fat: and edema of the extracostal chest wall. Each parapneumonic effusion was assigned a CT score on the basis of these CT findings. Individual CT findings and the CT score were correlated with the presence of empyema as determined by thoracentesis or thoracoscopy. RESULTS: Thirty patients were identified as having a parapneumonic pleural effusion revealed on contrast-enhanced CT scans and by pleural fluid analysis. Twenty-one of these parapneumonic effusions met the clinical criteria for empyema, and nine were considered not to be empyemas. Neither any individual CT finding nor the CT score accurately differentiated empyema from transudative parapneumonic effusions (p > .1): pleural enhancement (empyema 100%, transudative effusion 89%), pleural thickening (empyema 57%, transudative effusion 56%), abnormal extrapleural space (empyema 66%, transudative effusion 67%), extracostal chest wall edema (empyema 33%, transudative effusion 56%), and average CT score (empyema 2.5. transudative effusion 2.3). CONCLUSION: CT characteristics of parapneumonic effusions do not allow radiologists to accurately predict empyema. The presence or absence of such CT findings should not influence therapeutic decisions concerning the management of parapneumonic effusions.

Subpleural sparing: a CT finding of lung contusion in children.

PURPOSE: To evaluate the presence of subpleural sparing as an aid in differentiation of contusion from other causes of lung opacification in children. MATERIALS AND METHODS: In 29 children, the computed tomographic (CT) features of 40 lung contusions were reviewed for the presence of subpleural sparing. Other CT characteristics of lung contusion such as location, shape, and confluence were also evaluated. The presence of subpleural sparing was also evaluated in cases of atelectasis, pulmonary laceration, and a control group of CT scans obtained in 45 patients with bacterial pneumonia and no history of trauma. RESULTS: Subpleural sparing was seen at CT in 38 (95%) of the lung contusions and none of the cases of atelectasis, laceration, or pneumonia (P = .0001). Lung contusions tended to be posterior (60%), crescentic (50%), or amorphous (45%) and have confluent and nodular components (70%). CONCLUSION: The presence of subpleural sparing on CT scans enables accurate identification of lung contusion and differentiation of contusion from other causes of lung opacification in children after trauma.

Pneumonia in children: decreased parenchymal contrast enhancement--CT sign of intense illness and impending cavitary necrosis.

PURPOSE: To determine if computed tomographic (CT) findings of decreased contrast material enhancement are predictive of more intense illness and of the development of cavitary necrosis in children with pneumonia. MATERIALS AND METHODS: Contrast-enhanced CT scans in 44 children with pneumonia who did not respond appropriately to therapy were compared with precontrast CT scans to evaluate enhancement of consolidated lung parenchyma. Enhancement was correlated with admission to the intensive care unit, length of hospital stay, cavitary necrosis in the lung at follow-up CT, and frequency of lung resection. RESULTS: Parenchymal enhancement was decreased in 21 children; pneumonia was enhanced in the other 23 children. Decreased enhancement was associated with increased admission to intensive care (14 of 21 [67%] vs five of 23 [22%] children; P = .0026), increased length of hospital stay (15 vs 10 days; P = .0615), increased frequency of cavitary necrosis at follow-up CT (seven of seven [100%] vs none of three children; P = .0086), and increased frequency of resection (two of 21 [10%] vs none of 23 children). At histopathologic examination, diffuse cavitary necrosis was present in resected lobes in two patients. CONCLUSION: Decreased parenchymal enhancement at CT is a predictor of more intense illness and may herald the development of cavitary necrosis in children with pneumonia.

Frequency of right lower quadrant position of the sigmoid colon in infants and young children.

PURPOSE: To evaluate the frequency of right lower quadrant positioning of the sigmoid colon in infants and young children. MATERIALS AND METHODS: Findings in 169 patients who underwent enema examination were retrospectively reviewed. Sigmoid colon position was categorized as in the left or right lower quadrant or midline. Patients who had an anatomic abnormality that affected colonic position (eg, malrotation or abdominal mass) or had previously undergone abdominal surgery were excluded. The frequency of right lower quadrant sigmoid position was evaluated for a relationship with patient age (analysis of variance) and sex (chi(2) test). RESULTS: Patient ages were 1 day to 5 years (mean age, 13 months). The sigmoid colon was in the right lower quadrant in 74 (44%), in the left lower quadrant in 73 (43%), and in the midline in 18 (11%). The position was variable in one patient and indeterminate in three. When the sigmoid colon was within the right lower quadrant, it often extended laterally, overlying the position of the cecum and ascending colon. There were no significant correlations between right lower quadrant position and patient age (P =.262) and sex (P =.162). CONCLUSION: In children, the sigmoid colon is often within the right lower quadrant. Knowledge of this high frequency should reduce the likelihood of misinterpreting air within a redundant right-sided sigmoid colon as air within the cecum in children suspected of having abnormalities such as intussusception.

Airway compression in children with abnormal thoracic configuration.

PURPOSE: To assess the clinical and imaging findings in children with severe tracheal or bronchial compression caused by abnormal thoracic configuration. MATERIALS AND METHODS: Clinical and imaging findings, care, and outcome were reviewed in six patients with airway compression caused by abnormal thoracic configuration. Radiographs and magnetic resonance (MR) images were available in all patients. RESULTS: Mechanisms of airway compression included alteration of mediastinal anatomy and direct airway compression secondary to a narrow anteroposterior chest diameter. In three patients, the trachea was compressed at the level of the thoracic inlet. In the other three patients, the left main bronchus was compressed. Four patients underwent surgery for the thoracic deformity, with resolution of airway symptoms. In all four patients, the presence, location, and cause of airway obstruction determined at MR imaging were confirmed at surgery. CONCLUSION: Abnormal thoracic configuration, in addition to causing restrictive lung disease, can cause respiratory distress secondary to severe compression of the central airways.

The yield of CT of children who have complicated pneumonia and noncontributory chest radiography.

OBJECTIVE: Our purpose was to investigate the usefulness of CT in evaluating children who do not respond appropriately to treatment for pneumonia, when chest radiography is noncontributory. MATERIALS AND METHODS: Fifty-six contrast-enhanced CT scans were compared with radiographs obtained on the same day in children with complicated pneumonia. CT scans were evaluated for clinically significant findings that were not revealed by radiography: lung parenchymal complications (cavitary necrosis, abscess, decreased enhancement, bronchopleural fistula, or cavity suspected on radiography but not seen on CT), pleural complications (loculation, malpositioned chest tube), inaccurate estimation of cause of chest opacity on radiography (pleural versus parenchymal), bronchial obstruction, or pericardial effusion. RESULTS: One hundred ten CT findings, not revealed by radiography, were seen on 56 CT scans (2.0 per CT scan): parenchymal complications (n = 40), pleural complications (n = 37), inaccurate estimation of cause of chest opacity on radiography (n = 20), pericardial effusion (n = 13). All CT scans showed at least one significant finding (100% yield) not seen on radiography. CONCLUSION: In the evaluation of children with complicated pneumonia, CT often reveals clinically significant findings not apparent on radiography.

Cavitary necrosis complicating pneumonia in children: sequential findings on chest radiography.

OBJECTIVE: The objective of this study was to describe the sequential clinical and radiographic findings of cavitary necrosis complicating pneumonia in childhood. MATERIALS AND METHODS: A study group of 17 children (mean age, 6 years) was identified by reviewing CT examinations of all patients who underwent CT of the chest to evaluate possible complications of pneumonia over a 3-year period. Children included in the study group were those who met the criteria for cavitary necrosis: loss of lung architecture, decreased enhancement, and multiple cavities with thin, nonenhancing walls. In the 17 identified cases, sequential chest radiographs were reviewed for visibility of a lung cavity. Long-term follow-up radiographs were evaluated for persistent abnormalities. RESULTS: Ten of the 17 cases of cavitary necrosis seen on CT showed cavities at some time on radiography: one cavity was visible at the time of diagnosis on CT and nine were visible only later. All three cavities that were predominantly air-filled on CT were revealed by radiography, whereas 50% (7/14) of predominantly fluid-filled cavities were revealed by radiography. Eleven children underwent follow-up radiography more than 40 days after the diagnosis of cavitary necrosis. Radiographs of those 11 children showed clear lungs without pulmonary sequelae. CONCLUSION: In children, cavitary necrosis is associated with severe illness; however, cases usually resolve without surgical intervention, and long-term follow-up radiography shows clear lungs without pulmonary sequelae. Evidence of cavitary necrosis complicating pneumonia is often seen on CT before or in the absence of findings on chest radiography.

Acute graft-versus-host disease in children: abdominal CT findings.

PURPOSE: To review the computed tomographic (CT) appearance of acute gastrointestinal graft-versus-host disease (GVHD) in children. MATERIALS AND METHODS: Sixteen abdominal CT scans obtained in 12 children with acute gastrointestinal GVHD who underwent allogeneic bone marrow transplantation (BMT) were compared with 16 CT scans obtained in autologous bone marrow recipients not at risk for GVHD (control group). Autopsy findings in six patients with GVHD were compared with CT findings. RESULTS: All CT scans in patients with GVHD showed an abnormally enhanced, thin mucosal layer of bowel wall involving fluid-filled, dilated, poorly opacified bowel loops from the duodenum to the rectum. This corresponded histologically to mucosal destruction and replacement by a thin layer of highly vascular granulation tissue. Bowel wall thickening was often absent. Infiltration of mesenteric fat was seen in 91% of patients The control group showed no similar abnormalities. CONCLUSION: Acute gastrointestinal GVHD characteristically appears on CT scans as multiple, diffuse, fluid-filled bowel loops with a thin, enhancing layer of bowel wall mucosa. Bowel wall thickening often is absent.

MR imaging of conotruncal abnormalities.

MR imaging has been shown to be accurate in the diagnosis and follow-up of congenital abnormalities of the heart and great vessels in infants and children [1-3]. Although echocardiology, in many cases, remains the primary imaging technique in congenital heart disease, MR imaging is a useful adjunct [1-3]. The advantages of MR imaging include a wide field of view and multiplanar capabilities [1-3]. Echocardiology is often suboptimal in evaluating the superior mediastinum because of the narrow imaging window [3]. This fact is especially true in patients after surgery and in older children. Therefore, MR imaging often plays a role in the evaluation of the great vessels.

Abnormalities of the chest wall in pediatric patients.

A variety of focal processes and diffuse abnormalities are found predominantly in children. In addition, thoracic manifestations of trauma differ in children because of increased chest wall compliance. Familiarity with both these abnormalities as well as the common normal variations provides optimal imaging evaluation.

Thrombocytopenia and absent radii (TAR) syndrome associated with horseshoe kidney.

The TAR syndrome is an inherited disorder characterized by limb abnormalities, especially absent radii, and hypomegakaryocytic thrombocytopenia. Previous reports have included two infants with genitourinary abnormalities. We report a newborn with bilaterally absent radii and foreshortened ulnae, hypoplastic humeri, a left clubfoot, a ventricular septum defect, and persistent thrombocytopenia. This constellation of abnormalities is consistent with the TAR syndrome. In addition, he had a horseshoe kidney with parenchyma of normal appearance. This is the first report of horseshoe kidney in association with the TAR syndrome.