Catheter-based closure of atrial septal defects in the oval fossa with the Amplatzer device in patients in their first or second year of life.

OBJECTIVE: To assess feasibility, safety, and efficacy of the use of Amplatzer occluders in closure of atrial septal defects (ASD) in children in the first 2 years of life. BACKGROUND: Although scattered reports on such closure have been published, no agreement consists on the policy. METHODS: In 654 patients of all ages, closure was achieved in 632 (96.6%). Data were analyzed retrospectively in all 71 children where an attempt had been made to close the ASD before their second birthday. RESULTS: Median age and body weight were 17.2 months (range 3.9-23.8) and 10.0 kg (range 3.8-14.5), respectively. Median fluoroscopy time was 13.6 min and median device size 15 mm. Successful closure was achieved in 68 children (95.8%). Three times the procedure was aborted: in one, the device repeatedly straddled the septum; in the other two, a small left atrium restricted the movement of the left-sided disc. One device embolized and was reimplanted after retrieval. One infant with multiple disorders died 6 days after closure from acute sepsis probably unrelated to the procedure. No other complications occurred. Only trivial shunts closing with time were registered during follow-up. Symptomatic patients profited markedly from closure. CONCLUSION: The results and complications of ASD closure with the Amplatzer device in patients in their first 2 years of life compare favorably with procedures in older patients, provided that the size of the septum and the dimensions in the left atrium are taken into consideration when selecting the size of the device.

Iohexol and metrizamide for urography in infants and children.

The new nonionic contrast medium iohexol, was compared with metrizamide in a double blind investigation. Urography was performed in 40 children below 6 years of age. Adverse reactions were negligible. A small decrease in erythrocyte volume fraction (hematocrit) values after the injection was found in both groups. Excellent films were obtained in most patients and no difference in diagnostic quality between the two media was observed.

Absence of activation of proteolytic enzymes by extracorporeal shock waves.

The mechanism of tissue damage by extracorporeal shock wave lithotripsy has not been clarified, but proteolytic enzymes are known to play an important role in tissue breakdown in response to other types of injury. Screening tests for activation of the proteolytic enzymes kallikrein, plasmin, trypsins 1 and 2, and granulocyte elastase therefore were performed for 4 to 5 hours in 14 dogs after unilateral treatment with 1500 or 2000 extracorporeal shock waves under anesthesia and vigorous hydration. We also studied the activity of the proenzymes prekallikrein, plasminogen, and prothrombin and three plasma protease inhibitors (kallikrein inhibitor, antiplasmin, and antithrombin III). Blood from both renal veins (treated and control kidneys) and the aorta and tissue samples of the injured renal parenchyma and corresponding areas of the control kidneys revealed no proteolytic enzyme activation by the shock waves and no decline in the activities of proenzymes and enzymes inhibitors. Significant proteolysis does not seem to play a part in the tissue injury induced by extracorporeal shock wave lithotripsy.

Complementary investigations in bronchiectasis in children.

The different modalities suitable for image-guided diagnosis of bronchiectasis in children are described. Plain chest radiography is still the most important imaging method of respiratory disease in children, but when it comes to ascertaining the diagnosis of bronchiectasis, high-resolution computed tomography (CT) is currently the method of choice. Ultrafast computed tomography and multislice computed tomography have increased the value of computed tomography as a diagnostic tool by reducing the need for sedation or anaesthesia. Bronchography is as a rule no longer necessary to perform on this indication alone. If modern, high-quality computed tomography is not readily available, however, bronchography may still be necessary preoperatively.

The risk of spontaneous pneumothorax in patients with osteogenic sarcoma and testicular cancer.

Seven cases of unilateral, spontaneous pneumothorax were found in a retrospective study of 63 patients with osteogenic sarcoma who were admitted to The Norwegian Radium Hospital (NRH) in the period 1970--1977. The relative risk of pneumothorax developing doubled, from 7--14%, after the introduction of chemotherapy for this disease at NRH. This difference was not statistically significant. Pneumothorax developed in two of 18 patients (11%) with lung metastases who never received chemotherapy. Pneumothorax occurred in four of 19 patients (21%) treated with chemotherapy for manifest lung metastases, and in one of eight patients (13%) who received adjuvant chemotherapy, but in whom lung metastases developed later. Pneumothorax did not develop in 79 patients treated with chemotherapy for disseminated testicular cancer, despite the fact that 82% of these patients had manifest lung metastases.

Computed tomography and angiography in hepatocellular carcinoma.

Computed tomography and angiography were performed in 12 patients with hepatocellular carcinoma, all demonstrated with CT. In 11, the tumor had a lower attenuation than the liver parenchyma, in one a higher attenuation. Two patients had 2 lesions. The hepatic contour protruded in 10 patients. Angiography failed to demonstrate the tumor in 3 patients. The most common angiographic findings were arterial displacement in 8 patients and a hypervascular mass in 7.

Torsion of a wandering spleen in an infant. Report of a case and a brief review of the literature.

A case of torsion of the wandering spleen in an infant is presented. The value and limitations of various imaging modalities in making a correct preoperative diagnosis are discussed and a brief review of the literature is given.

Iohexol for contrast enhancement of bowel in pediatric abdominal CT.

Abdominal CT scans from 160 examinations performed on pediatric patients using iohexol 2 percent as contrast medium for bowel enhancement were evaluated retrospectively. When diluted with a beverage of the child's choice, iohexol has a neutral taste and cannot be detected, and 139 out of 142 patients drank the full amount of dilute contrast offered to them. The enhancement of bowel in the area of interest was graded as good (58%), reasonable (23%), or poor (19%). The contrast medium was prepared from leftovers from our angiocardiography studies. We conclude that the use of water-soluble contrast medium in a low concentration is a safe and cost-effective way of facilitating ingestion of sufficient amounts of the medium in oncologic pediatric patients undergoing cytotoxic and/or radiation treatment.

[Magnetic tomography--new imaging techniques and future perspectives]. / Magnettomografi innenfor pediatrisk radiologisk diagnostikk.

BACKGROUND: MRI is a promising imaging technique for diseases in most organ systems in children. MATERIAL AND METHODS: This review discusses MRI on the basis of the literature and our own experience. RESULTS: The value of MRI in paediatric neuroradiology is firmly established. In congenital heart defects and other reasons for cardiovascular imaging in children, the non-invasiveness of the method is appealing. MRI is already included in most international paediatric oncology protocols. Paediatric applications for MRI differ from those in adults as they focus on developmental and congenital abnormalities. Furthermore, some pathological conditions are unique to children. MRI is also a promising alternative to established methods for evaluation of the urinary tract. There are some specific problems with MRI in children. Immobilisation and sedation techniques include tight wrapping of the newborn with soft elastic bands, feeding immediately prior to the study, and allowing one parent into the magnet with the child. Midazolam and oral chloral hydrate are usually used for sedation. INTERPRETATION: MRI is of particular value in the paediatric age group as the method is capable of highly accurate imaging in a variety of congenital and paediatric diseases without the use of ionising radiation. Faster sequences and better resolution will further increase the use of MRI in children.

Iohexol and metrizamide for urography in infants and children.

The new non-ionic contrast medium iohexol, was compared with metrizamide in a double blind investigation. Urography was performed in 40 children below 6 years of age. Adverse reactions were negligible. A small decrease in erythrocyte volume fraction (hematocrit) values after the injection was found in both groups. Excellent films were obtained in most patients and no difference in diagnostic quality between the two media was observed.

[The "umbrella closure" of the ductus arteriosus]. / Paraplylukking av ductus arteriosus.

The technical details of the method are outlined, and the Norwegian experience reported: From September 1988 to January 1994 we attempted to close open ducts with the Rashkind technique in 26 patients. Two ducts were too small to accept the device, and in one case the implanted device could not be released. This patient was referred to surgery. In the remaining 23 patients the device was left in place. The mean X-ray fluoroscopy time was 15 minutes. No complications occurred. In eight patients (35%) a residual shunt could be detected by ultrasonic Doppler technique, but in seven of them haemodynamical significance was lacking. The umbrella method is a good alternative to traditional treatment.

Computed tomography and angiography in carcinoid liver metastases.

Fifteen patients with carcinoid metastases in the liver were examined with computed tomography (CT). In 13 patients, liver metastases were demonstrated, while 2 patients had a normal liver at CT. The attenuation of the metastases was lower than that of the liver parenchyma in 12 patients, higher in one. Angiography was performed on 10 patients, and liver metastases were diagnosed in 9. Eight patients had hypervascular metastases with dense accumulation of contrast medium. In one patient, displacement of the intrahepatic arteries was the only sign of an expansive process. In one patient, previously treated with ligation of the common hepatic artery, no signs of liver metastases could be revealed at angiography but were evident at CT.

Liver attenuation values at computed tomography related to liver copper content.

Forty-three patients were examined with computed tomography of the liver and liver biopsies with measurement of hepatic copper content. All recorded liver attenuation values were within normal range, even in patients with markedly elevated hepatic copper content. No statistically significant correlation between the liver attenuation values and the copper concentrations in liver tissue was demonstrated. At present, therefore, computed tomography has no place in monitoring the development of copper accumulation.

Acute morphological changes in canine kidneys after exposure to extracorporeal shock waves. A light and electron microscopic study.

The acute effects of extracorporeal shock waves on renal morphology were studied by light and electron microscopy in 14 dogs. One kidney received an average clinical number of exposures, the nonexposed, contralateral kidney serving as control. The original Dornier HM-3 generator was used in 3 animals, the modified version in 11. Intravascular radiographic contrast medium was administered in five animals. Damage was observed in all exposed kidneys, none in the contralateral control kidney. The effects were characterized by renal and perirenal hemorrhage and edema, parenchymal hemorrhagic foci with tissue destruction, often extending from cortex to medulla. In the nearby regions there was endothelial cell damage in arteries, veins and glomerular capillaries. Breaks in the wall of these vessels were detected with platelet plug formations and thrombi. In glomeruli, breaks of Bowman's capsule and epithelial cell damage with loss of foot processes were observed. A wide range of tubular cell damage was demonstrated, ranging from vacuolization to complete necrosis. Tubular lumina were filled with red cells, indicating renal origin of hematuria. The tissue damage was less pronounced in kidneys exposed to the modified lithotriptor than to the original. No difference in the quantity or quality of damage was detected whether radiographic contrast medium was administered or not.

Does the administration of systemic radiographic contrast media influence the acute changes in renal physiology following exposure to extracorporeal shock waves in dogs?

Five anesthetized dogs were studied for 4 to 5 hours after administration of extracorporeal shock waves to one kidney, the contralateral organ serving as control. Repetitive major doses of the nonionic monomeric radiographic contrast medium (CM) iohexol were injected intravascularly before and after application of the extracorporeal shock waves for further provocation of kidney function. Urinary excretion of electrolytes, N-acetyl-beta-glucosaminidase (NAG) and kallikrein, clearances of creatinine, inulin and para-amino-hippuric acid (PAH), serum aldosterone level and plasma renin activity (PRA) were determined. On the exposed side there was a significant fall in urinary osmolality. Effective renal plasma flow (ERPF) was reduced and glomerular filtration rate (GFR) was unchanged; thus filtration fraction (FF) was increased. Extraction of PAH was reduced, and true renal plasma flow was unchanged. Urinary osmolality on the control side was unchanged. There was a fall in ERPF and increased GFR; therefore, FF increased. The mean rise of PRA in the exposed kidney was significant after shock waves. Urine volume and urinary excretion of electrolytes and kallikrein were stable bilaterally. Relating the results to those obtained in identical canine experiments without CM, simultaneous administration of CM does not seem to significantly influence the changes in kidney function parameters caused by extracorporeal shock waves in the dog.

Computed tomography of a tuberculous paravertebral abscess.

Spinal tuberculosis with extensive abscess formation in a 5-year-old girl of Asian origin is reported. The role of CT in the preoperative visualisation of the different compartments of the lesion, including extra- and intraspinal extension, is discussed. At present, CT seems to be the method of choice in the preoperative study of infectious spinal and paraspinal processes.

[Percutaneous closure of ductus arteriosus using the umbrella technic]. / Perkutan lukning av ductus arteriosus med paraplyteknikk.

In four patients between three and five years of age we performed closure of open ductus arteriosus with the Rashkind umbrella technique after percutaneous approach from the right groin. The smallest internal ductus diameter measured between 2 and 4 mm, and pulmonary blood flow was from 1.4 to 2.0 times systemic flow. In all four patients, pulmonary artery pressure was normal. In three patients the ductus arteriosus was completely closed, in the fourth a small residual shunt persisted. There were no complications. We describe the method in detail.