Magnetic resonance evaluation of disease of the soft tissues in children.

Magnetic resonance imaging was a sensitive modality for identifying pathology in the soft tissues of 32 children, and it consistently showed more abnormality than CT. Magnetic resonance images are not histology specific, but with careful attention to the location of the abnormality, to the definition of the margins, and to the evaluation of involvement of adjacent muscle, bone, subcutaneous fat, and skin, the correct diagnosis can be strongly predicted in most cases. The ability of magnetic resonance to image in multiple planes aids in the evaluation of the extent of lesions and their relationship to adjacent structures. With magnetic resonance imaging, one can accurately predict the extent of abnormality, and there is great potential for the study of disease of soft tissues.

Efficacy of magnetic resonance imaging in 139 children with tumors.

One hundred thirty-nine children with neoplasms were studied using magnetic resonance imaging (MRI). This procedure was as accurate as computed tomography in predicting tumor histology, except that MRI was unable to detect small areas of tumor calcification. Magnetic resonance imaging could accurately identify the organ of origin of tumor masses and differentiate soft tissue from fat, fluid, or hemorrhage. In addition, MRI was helpful in planning surgery in many cases: It was better than computed tomography in defining the size and extent of soft-tissue tumor masses. It was accurate in defining the extent of the spread of bone sarcomas in the bone marrow. Without requiring the injection of intravenous contrast agents, it accurately defined displacement, encasement, or invasion of major abdominal blood vessels by Wilms' tumors and neuroblastomas. As a means of evaluating pediatric neoplasms, MRI is noninvasive, painless, and well tolerated by children, and it uses no radiation.

Magnetic resonance imaging of inflammatory lung disorders: preliminary studies in children.

Magnetic resonance(MR) scans were performed on 14 children with a variety of inflammatory disorders of the lungs. MR successfully identified disease in all of the children and accurately localized the disease within the lung fields. In patients with pneumonia and lung abscesses the acute inflammation was associated with a marked increase in signal intensity on T2 when compared with T1 weighted images. One patient with an inflammatory pseudotumor demonstrated a smaller increase in signal intensity on T2 weighted images than was seen in acute pneumonia. Abscess cavities were well identified along with the wall thickness. In patients with diffuse lung disease (diffuse histoplasmosis, miliary tuberculosis, Letterer-Siwe disease, and allergic alveolitis), each disease appeared different on the MR images. These preliminary studies indicate that magnetic resonance imaging is effective for identifying pulmonary disease in children and may improve the radiologist's ability to differentiate pulmonary disorders.

Ingested manganese chloride as a contrast agent for magnetic resonance imaging.

Solutions of manganese chloride were force-fed to Sprague-Dawley rats. Magnetic resonance (MR) imaging was performed on (a) syringes containing different concentrations of manganese chloride, (b) rats after force feeding and (c) livers excised after sacrifice of the force-fed rats. Imaging was done with a 0.15-T resistive magnet. Multiple pulse sequences were used and T1 values were calculated. The signal intensity and T1 value obtained from a solution depended on the manganese concentration and the pulse sequence employed. At higher concentrations, no signal was produced due to extreme T2 shortening. Absorbed manganese affected the signal intensities and T1 values of the rats' livers. By appropriate selection of manganese concentration and pulse sequence, ingested manganese can serve as a combined gastrointestinal and hepatic MR contrast agent.

Subepithelial pyeloureteric lesions in patients with nephrostomy tubes.

Mural filling defects were identified in the renal pelves or ureters in five patients with nephrostomy tubes. In two patients, infection was documented. In the remaining patients, the urine was sterile. While typical ureteritis cystica associated with infection may be seen in patients with nephrostomy tubes, in some patients, other mechanisms are responsible for this appearance.

Evaluation of pulmonary parenchymal disease by magnetic resonance imaging.

Thirty-eight patients with a wide variety of different disorders of the lung have been imaged using magnetic resonance. The disorders studied include congenital abnormalities, acute and chronic inflammation, vascular disorders, primary and secondary tumours of the lung, haematomas and infarcts. Magnetic resonance imaging identified all lesions seen on chest radiographs, but it is not quite as sensitive as computed tomography is for detection of very small abnormalities. Magnetic resonance may provide information to aid in differentiation of a wide variety of disorders causing diffuse pulmonary abnormality and might also prove helpful in differentiating acute inflammation from pulmonary collapse or fibrosis. In some disorders, such as lobar emphysema, cystic adenomatoid malformation and sequestration, the findings on the magnetic resonance scan alone will permit a correct diagnosis to be made in many cases. It is believed that magnetic resonance imaging has more potential for pulmonary imaging than has previously been recognised.

Imaging the diaphragm and its disorders.

Although a radiologic evaluation of the diaphragm is important in many clinical situations, visualization of the diaphragm is difficult because of its thinness, its domed contour, and its contiguity with abdominal soft tissues. Each clinical situation involving the diaphragm presents its own imaging difficulties, and each radiographic technique has advantages and disadvantages. No one modality is best for all situations. Often, several imaging modalities must be used to resolve the clinical question. The particular difficulties in diaphragmatic imaging are (1) distinguishing eventration from paralysis or hernia, (2) distinguishing lipoma from herniated omental fat, and (3) distinguishing unilateral paralysis from weakness and bilateral paralysis from respiratory fatigue. By selecting and applying the appropriate radiographic techniques, the radiologist can serve an essential role in assessing the disorders of the diaphragm.

Laser cameras and radiology department design.

Although newer imaging modalities provide many options for the acquisition, processing, storage, and display of images, film is still an important means of storing and displaying images. Laser cameras may be used to record images from a variety of imaging instruments on film, offering several advantages over conventional multiformat cameras. When a laser camera purchase is planned, several installation requirements must be kept in mind. These are illustrated by showing how laser cameras have been incorporated into a new radiology department.

Simultaneous renal vein thrombosis and bilateral adrenal hemorrhage: MR demonstration.

A case of simultaneous renal vein thrombosis and bilateral adrenal hemorrhage is presented, demonstrating the ability of magnetic resonance (MR) imaging to identify these abnormalities without the use of intravenous contrast agents or radiopharmaceuticals. Adrenal hemorrhage appeared as markedly enlarged adrenal glands with homogeneous high signal intensity on both T1 and T2 weighted spin echo MR images. The kidney involved with renal vein thrombosis was enlarged and demonstrated increased signal from the renal parenchyma on T2 weighted images.

Mass spectrometry of some ultraviolet absorbing derivatives of sugars and related alditols: identification in biologic fluids after separation by high performance liquid chromatography.

The 70 eV electron impact mass spectra of the acyclic perbenzoyl 0-benzyloximes of several mono- and disaccharides of clinical interest and the perbenzoates of certain related alditols have been obtained and compared with those of other similar derivatives studied previously. In general, the spectra of the benzyloximes contain molecular ions and characteristic fragments due to [C6H5]+,[C7H7]+,[C6H5CO]+ and [C6H5CooH]+., losses of HCHO, C6H5COO. and C6H5COOH, and cleavages along the carbon chain. The most unique ions in these spectra arise from the combined loss of C7H7. and C6H5COO.from the molecular ion: m/z 191 (C3), m/z 339 (deoxy-C5), m/z 459 (C5), m/z 473 (deoxy-C6), and m/z 593 (C6). The alditol benzoates fragment similarly, but they do not yield molecular ions. These data are being used to help confirm the identities of carbohydrates in biologic fluids fractionation by high performance liquid chromatography, prior to the establishment of routine quantitative assays for several of these compounds.

Thymus in the superior mediastinum simulating adenopathy: appearance on CT.

A soft-tissue nodule was identified in the mediastinum superior to the left brachiocephalic vein in six patients undergoing computed tomography (CT) of the chest. In one case, biopsy of the mass showed that it was thymic tissue. In the remaining cases, the nodule was identified as thymus on the basis of the CT findings. The findings include equal density of the superior mediastinal nodule and the thymic lobes anterior to the ascending aorta, no displacement or narrowing of adjacent arteries, absence of a fat plane between the nodule and the thymic lobes, and parallel reduction in size of the nodule and the rest of the thymus. Two patients were examined with magnetic resonance (MR) imaging. Sagittal MR images demonstrated continuity of the superior mediastinal nodule with the more caudal portion of the thymus. Recognition of this normal variant in children is important in order to avoid unnecessary mediastinal biopsies or overstaging of malignancies.

Percutaneous nonendoscopic gastrostomy in children.

Surgical gastrostomy has long been a standard method of providing nutrition to infants and children. Recently, percutaneous endoscopic gastrostomy has been advocated as a safer, quicker, less expensive method in children. We report our experience with 16 percutaneous gastrostomies in 14 infants and children; in all cases, both sonographic and fluoroscopic guidance were used. Four patients had had previous surgical gastrostomy in which the tubes could not be replaced once they were removed. The remaining patients were referred for percutaneous placement of gastrostomy tubes as the first procedure. In 13 procedures, parenteral sedation and local anesthesia were used; the remaining three procedures were done with the patient under general anesthesia. Tubes were successfully placed in all procedures. In two patients, tubes became dislodged, necessitating a second procedure. There were no instances of local infections, hemorrhage, or peritonitis, and none of the patients died. Two patients had postprocedure septicemia, which responded to antibiotics. Percutaneous nonendoscopic gastrostomy can be safely and effectively performed in infants and children.

Uptake of technetium 99m MDP by hepatoblastoma.

Focal uptake of 99mTc-MDP was seen in a case of hepatoblastoma. The focal uptake corresponded to an area of calcification on CT, which was shown histologically to consist of osteoid with mineralization. The mechanism of uptake by the tumor in this case is likely to be the same as for skeletal uptake.

CT cholangiography of a choledochocele.

Choledochocele is a rare anomaly which has been imaged by a variety of techniques, including CT. A case of choledochocele in an eleven-year-old boy is reported. CT demonstrated a fluid-filled lesion protruding into the lumen of the duodenum and containing stones. CT following oral cholangiogram contrast administration and intravenous sincalide confirmed connection of the cystic lesion with the biliary tree. This is a safe and noninvasive method for the diagnosis of choledochocele.

Society for Pediatric Radiology John Caffey Award. MR appearance of blood and blood products: an in vitro study.

There are conflicting reports on the appearance of blood and blood clot as seen in the human body by MRI. This study was designed to show the in vitro MR signal intensity of human blood products in the fresh state and to evaluate the serial MRI changes that occur over time (2 weeks). T1 relaxation times were also measured. Anticoagulated whole blood, plasma, serum, white blood cell concentrates, platelet concentrates, lysed red cells, red cell concentrates, and blood clot were studied. The results show that plasma and serum have similar T1 values, as do lysed and intact erythrocytes. T1 of serum and plasma rose initially and then fell with the aging of the samples. T1 of red blood cells, clot, and packed red blood cells decreased for the first 48 hr and then remained constant for 7 days before increasing to the initial values by 2 weeks. Platelets and white blood cells had little influence on the MR image. However, temperature had a significant effect on T1 and signal intensity. In vivo clots are complex mixtures of whole clot, lysing clot, serum, and plasma influenced in various ways by the adjacent normal or diseased tissues. The chemical and physical properties of the mixture change constantly. Because of the clot's complex nature, determining the age of a hematoma from the appearance of clots on the MR image may not be possible.

Retroaortic left renal vein demonstrated by nuclear magnetic resonance imaging.

A case of retroaortic left renal vein is presented, demonstrating the ability of nuclear magnetic resonance imaging to identify vascular anomalies without the use of contrast agents.

Magnetic resonance differentiation of acute and chronic osteomyelitis in children.

A comparison has been made of the MRI findings of 17 studies in 16 patients with osteomyelitis: eight studies were performed in patients with acute osteomyelitis, six in chronic and three in healed osteomyelitis. Soft tissues, cortex and marrow were assessed in all patients. The best predictors of acute osteomyelitis were poorly defined soft tissue planes, absence of cortical thickening, and a poor interface between normal and diseased marrow. In contrast, chronic osteomyelitis was suggested by the presence of well-defined soft tissue abnormality, thickened cortex, and a relatively good interface between normal and diseased marrow. The appearance of osteomyelitis did not vary in different anatomic sites.