Magnetic resonance imaging of the fetus in congenital intrathoracic disorders: preliminary observations.

BACKGROUND AND OBJECTIVE: Advances in magnetic resonance imaging (MRI) provide high-quality images of the intrathoracic organs. We studied the ability of MRI to define spatial relationships of the fetal lungs and measured lung volume in two cases of congenital diaphragmatic hernia (CDH), one of severe oligohydramnios secondary to bilateral cystic renal dysplasia and one case of prenatal chylothorax. PATIENTS AND METHODS: We performed pelvic MRI using single-shot fast spin echo (SSFSE) pulse sequence in four pregnant women referred because of abnormal prenatal ultrasound (US) findings associated with pulmonary hypoplasia. RESULTS: The exact anatomic position of the contents of the hernia in CDH, including the position of the liver, was better defined with MRI. Pleural effusions were identified as well as the renal abnormality in the case of oligohydramnios. Lung volume was measured and the degree of pulmonary hypoplasia was quantified in every case. Lung-to-thorax ratio was calculated in the case of fetal chylothorax. CONCLUSION: Ongoing work suggests that MRI can provide additional detailed quantitative information in prenatal disorders associated with fetal lung compression and resulting hypoplasia. Correlation of fetal lung volume with postnatal management and outcome may affect prognosis in these cases.

Pediatric radiology at the millennium.

PURPOSE: To evaluate the current practice of and job market for pediatric radiologists in the United States and Canada with a 1998 survey and compare findings with those of surveys from 1980 and 1989. MATERIALS AND METHODS: Surveys were mailed to the 728 active members of the Society for Pediatric Radiology. Questions covered professional practice, subspecialization, and involvement in evolving technologies. A pediatric radiology help-wanted index was generated from a diagnostic radiology help-wanted index. RESULTS: Increasing involvement in the interpretation of computed tomographic, ultrasonographic, and magnetic resonance images was found among the 57% (411 of 728) of the members who responded. The attainment of a certificate of added qualification in pediatric radiology was found in nearly three-fourths of the membership, and 85% (348 of 408) had completed a fellowship. More than half of the respondents were involved in interventional procedures amid a continued increase in volume; 24% (100 of 409) of the membership, as compared with 7% in the 1980 survey, was practicing in a community or "other" setting. Subspecialization within pediatric radiology had diminished, and there was a larger percentage of female pediatric radiologists, particularly among the newest members. The job market was robust, having recovered substantially since the middle 1990s. CONCLUSION: The practice of pediatric radiology has evolved, with increasing involvement in advanced techniques and modalities, as well as a greater presence in community settings. The help-wanted index supports the recent discussions of a personnel shortfall.

Acute appendicitis in children: comparison of clinical diagnosis with ultrasound and CT imaging.

BACKGROUND: There is strong evidence that imaging with ultrasound and CT can be of substantial diagnostic value in the diagnosis of acute appendicitis in children, but there is limited information of the impact of imaging on the management of these patients and its possible effect on surgical findings. OBJECTIVE: We studied the impact of imaging in the management of acute appendicitis, in particular its effect on the rate of negative appendectomies and perforations. PATIENTS AND METHODS: We reviewed retrospectively the clinical records and imaging findings of 633 consecutive children and adolescents seen on an emergency basis with clinical suspicion of acute appendicitis. Two hundred seventy patients were operated upon on clinical evidence alone, while 360 were referred for US or CT, and occasionally both, because of doubtful clinical findings. RESULTS: Acute appendicitis was found in 237 of those on clinical grounds alone, 68 of whom had perforation and related complications. Thus the rate of negative exploration and the rate of perforation were13 % and 29 %, respectively. One hundred eighty-two patients had preoperative US (sensitivity 74 %, specificity 94 %), 119 had CT (sensitivity 84 %, specificity 99 %), and 59 had both US and CT (sensitivity 75 %, specificity 100 %, but often with interpretation at variance with each other). The rate of negative appendectomy and perforation was 8 % and 23 %, respectively, for US, 5 % and 54 % for CT, and 9 % and 71 % when both examinations were performed. There is no statistical significance between the rates of diagnostic performance of US, CT, or their combination, nor between the negative appendectomy rates of each group, but the rate of perforation was significantly higher when CT was performed, alone or after US. CONCLUSION: The retrospective nature of the study prevents precise definition of the clinical characteristics and selection criteria for diagnostic examinations that may contribute to the management of children with suspected acute appendicitis. It was designed, however, to reflect the diagnostic approach and management of these patients, under the care of many decision makers and interpreters of imaging examinations, prevalent today in most hospital-based clinical practices. It is suggested that imaging increases diagnostic accuracy in difficult cases, but it might be one of the factors increasing the rate of perforations.

Magnetic resonance imaging in acute pyelonephritis.

The diagnosis of acute pyelonephritis in children remains a clinical challenge. We assessed the feasibility of magnetic resonance imaging (MRI) detection of pyelonephritis in four pediatric patients and compared the results with renal cortical scintigraphy. MRI revealed areas of high signal intensity in the kidney that coincided with photon-deficient regions in the radionuclide scans in two children with acute pyelonephritis. These findings confirm work in experimental animals and indicate that MRI can accurately detect acute pyelonephritis in children.

The thymus: from past misconception to present recognition.

The critical role of the thymus in the development of the immune system was unknown until recently. For a long time physicians were puzzled by the presence of a large thymus in early life and attributed many symptoms to it. This review briefly covers the history of the thymus and its function as a primary lymphoid organ, along with a short background of the development of the immune system. Thymic diseases and their imaging features are also reviewed briefly.

The value of head ultrasound in infants with macrocephaly.

OBJECTIVE: To assess the value of head ultrasound (HUS) in neurologically normal infants with macrocephaly and to develop a rational approach to radiological investigation of macrocephalic infants. MATERIALS AND METHODS: A retrospective analysis of infants with macrocephaly (seen by one pediatric neurologist at this institution) was conducted. Infants with normal neurological examinations, no evidence of raised intracranial pressure and who had undergone a HUS were included. RESULTS: Twenty-seven infants were included in the analysis. Mean age at first assessment was 4.8 months. In 12 of 27 (44%), HUS was reported as normal. The remaining 15 had clinically insignificant abnormalities on HUS; 7 had prominent ventricles and 7 had increased subarachnoid fluid, with 1 infant having both. Seven infants had CT or MRI in addition to HUS. No clinically significant abnormalities were seen on CT or MRI scans that were not evident on HUS. Four infants had mild developmental abnormalities on initial evaluation. Mean duration of follow-up was 13.1 months. No infant developed neurological abnormalities during the follow-up period. CONCLUSION: In infants with macrocephaly with a normal neurological examination and no signs of raised intracranial pressure, HUS in conjunction with close neurological follow-up is reliable for the detection or exclusion of relevant intracranial pathology.

Liver and spleen MRI findings in virus-associated hemophagocytic syndrome in a patient with acute lymphocytic leukemia.

Virus-associated hemophagocytic syndrome is characterized by the phagocytosis of erthythrocytes and other blood elements in multiple organ systems, especially the liver and spleen. Magnetic resonance imaging (MRI) can suggest this diagnosis in the proper clinical setting by demonstrating multiple, rounded signal voids in the spleen corresponding to hemosiderin deposition. We report a patient with virus-associated hemophagocytic syndrome during the course of acute lymphocytic leukemia and MRI findings that suggested the preoperative diagnosis.

Thoracic neuroblastoma: what is the best imaging modality for evaluating extent of disease?

BACKGROUND: Thoracic neuroblastoma accounts for 15% of all cases of neuroblastoma. A minority of children with thoracic neuroblastoma will have dumbbell tumors, i.e., intraspinal extension, but only half these patients will have neurologic signs or symptoms. HYPOTHESIS: MR imaging is the single best test to evaluate the extent of thoracic and spinal disease in thoracic neuroblastoma after the diagnosis of a mass is established on plain film. MATERIALS AND METHODS: A retrospective multi-institutional investigation over 7 years of all cases of thoracic neuroblastoma (n = 26) imaged with CT and/or MR were reviewed for detection of the extent of disease. The chest film, nuclear bone scan, and other imaging modalities were also reviewed. The surgical and histologic correlation in each case, as well as the patients' staging and outcome, were tabulated. RESULTS: The chest radiograph was 100% sensitive in suggesting the diagnosis. MR imaging was 100% sensitive in predicting enlarged lymph nodes, intraspinal extension, and chest wall involvement. CT was 88% sensitive for intraspinal extension but only 20% sensitive for lymph node enlargement. CT was 100% sensitive in detecting chest wall involvement. Direct comparison of CT and MR imaging in six cases revealed no difference in detection of enlarged lymph nodes or chest wall involvement. Neither test was able to detect remote disease, as noted by bone scan. CONCLUSION: The chest film is 100% sensitive in suggesting the diagnosis of thoracic neuroblastoma; MR imaging appears to be the single best test for detecting nodal involvement, intraspinal extension, and chest wall involvement.

Extraperitoneal abdominopelvic inflammatory pseudotumor: report of four cases.

We describe four cases of inflammatory pseudotumor seen at our institution in the past 4 years. Four children were each found to have a large extraperitoneal mass on imaging studies, three of which were in the pelvis. Malignant sarcomatous tumors were suspected. Surgical biopsy of each mass, however, revealed inflammatory pseudotumor.

Pyloric volume: an important factor in the surgeon's ability to palpate the pyloric "olive" in hypertrophic pyloric stenosis.

OBJECTIVE: The objective of this study was to determine whether the size of the pyloric mass is one of the factors in the surgeon's ability to palpate the pyloric "olive". MATERIALS AND METHODS: The ultrasonographic images and medical records of 60 infants with surgically confirmed hypertrophic pyloric stenosis (HPS) were reviewed. The pyloric diameter (PD) and pyloric length (PL) were measured and the pyloric volume (PV) was calculated using the equation PV = 1/4pi x (PD)2 x PL. Based on the pediatric surgeon's physical examination the infants were divided into two groups: those with and those without palpable pyloric masses. RESULTS: Infants with a palpable pyloric mass had an average pyloric volume of 3.33 +/- 1.76 mm3, which was statistically larger than those whose hypertrophied pylorus could not be palpated (average volume 2.59 +/- 2.07 mm3, P < 0.01). There was no statistically significant age difference between the two groups. CONCLUSION: Clinical skill of the examiner and other clinical aspects (patient cooperation, etc.) determine palpability of the pylorus in HPS. The size of the hypertrophied pylorus is also an important factor affecting the clinician's ability to palpate the pyloric mass.

Spiral computed tomographic scanning of the chest with three dimensional imaging in the diagnosis and management of paediatric intrathoracic airway obstruction.

BACKGROUND: The usefulness of spiral computed tomographic (CT) scans of the chest with three dimensional imaging (3D-CT) of intrathoracic structures in the diagnosis and management of paediatric intrathoracic airway obstruction was assessed. METHODS: A retrospective review was made of five consecutive cases (age range six months to four years) admitted to the paediatric intensive care unit and paediatric radiology division of a tertiary care children's hospital with severe respiratory decompensation suspected of being caused by intrathoracic large airway obstruction. Under adequate sedation, the patients underwent high speed spiral CT scanning of the thorax. Non-ionic contrast solution was injected in two patients to demonstrate the anatomical relationship between the airway and the intrathoracic large vessels. Using computer software, three-dimensional images of intrathoracic structures were then reconstructed by the radiologist. RESULTS: In all five patients the imaging results were useful in directing the physician to the correct diagnosis and appropriate management. In one patient, who had undergone repair of tetralogy of Fallot with absent pulmonary valve, the 3D-CT image showed bilateral disruptions in the integrity of the tracheobronchial tree due to compression by a dilated pulmonary artery. This patient underwent pulmonary artery aneurysmorrhaphy and required continued home mechanical ventilation via tracheostomy. In three other patients with symptoms of lower airway obstruction the 3D-CT images showed significant stenosis in segments of the tracheobronchial tree in two of them, and subsequent bronchoscopy established a diagnosis of segmental bronchomalacia. These two patients required mechanical ventilation and distending pressure to relieve their bronchospasm. In another patient who had undergone surgical repair of intrathoracic tracheal stenosis three years prior to admission the 3D-CT scan ruled out restenosis as the reason for her acute respiratory decompensation. CONCLUSIONS: 3D-CT scanning is a useful additional diagnostic tool for intrathoracic airway obstruction in paediatric patients.

Human immunodeficiency virus infection and multilocular thymic cysts.

PURPOSE: Pathologic changes of the thymus, often seen in children with the human immunodeficiency virus (HIV), reflect direct invasion by the virus, followed by involution of the gland. A previously unknown form of thymic response to HIV infection, that of a multilocular thymic cyst, is reported. MATERIALS AND METHODS: Findings were examined in three HIV-positive patients, two children and one adult first seen with large thymic masses. RESULTS: All three had large, septate low-attenuation areas at computed tomography consistent with multilocular thymic cysts. The cystic nature of the lesions was confirmed with magnetic resonance imaging in two. Histopathologic examination, performed in two instances, helped establish the diagnosis. All patients remained in clinically stable condition. They all had parotid gland enlargement and lymphocytic interstitial pneumonia. CONCLUSION: Multilocular thymic cysts are probably another manifestation of the diffuse infiltrative lymphocytosis syndrome, usually associated with a milder course of acquired immunodeficiency syndrome.

Simultaneous occurrence of osteosarcoma and osteochondroma following treatment of neuroblastoma with chemotherapy, radiotherapy, and bone marrow transplantation.

Radiation-induced bone changes and second malignancies, as well as benign tumors, following bone marrow transplantation are being reported with increasing frequency. An osteosarcoma of the fourth right rib and an osteochondroma of the left scapula developed in a long-term survivor of abdominal neuroblastoma treated with chemotherapy, local radiation, and bone marrow transplantation. All these treatment modalities are known to induce neoplasia.