Biomedical subjects
Publications and source records attributed to H G Ringertz.
This report describes a malpractice case involving a delayed diagnosis of a malignant bone tumour in the proximal tibia in a 10-year-old child. This was caused by a combination of factors. The final report on the first examination failed to reach the patient files, and two subsequent X-ray exams failed to diagnose the tumour, due to misinterpretation in one and obscuring plaster of Paris in the other.
We report the case of a girl with known large right-sided and small left-sided neonatal adrenal haematomas who underwent bone scintigraphy 23 days after birth for suspected osteomyelitis. The radionuclide examination showed uptake of bone tracer around the right-sided haematoma, but no abnormality on the left side.
Radiological cases constituted 2% of the total number of legal cases in Sweden during 1996. The young man in this report accused a radiologist of having missed a fracture 7 years earlier based on a new radiology examination and report. In reality the latter report was incorrect and the patient had a rare exostosis that explained the clinical signs and symptoms. The alleged fracture was an epiphyseal line to a non-unified ossification centre at the tip of the unique exostosis.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Fourteen children under 3 years of age with possible airway obstruction were evaluated with an ultrafast CT scanner, Imatron C-100. Serial 0.05-second multilevel scans were obtained through the chest at rates of 17 images per second. No patient sedation or contrast medium was used. Time-density curves generated over each lung and specific pulmonary zones were compared to characterize the normal variation of density during inspiration and expiration and to determine abnormal patterns associated with airway obstruction. There was a high, positive correlation value (r greater than 0.79) between time/density curves over those pulmonary regions in which there was no focal bronchial obstruction and a low, negative correlation value (r = less than -0.58) with bronchial obstruction. Three studies with reconstruction artifacts were excluded. Furthermore, the results indicate that young children generally have denser lungs, particularly in expiration, than older children or adults. This preliminary study suggests that ultrafast CT offers a promising, unique, rapid and noninvasive approach for diagnosing airway obstruction in childhood.
A high-speed computed tomography (CT) scanner was used for measuring flow in a phantom and in the common carotid arteries of six dogs. The general ability of the scanner to assess flow using contrast media boluses was tested with the phantom. The validated simple concept was then used in the animals. The carotid blood flow was varied with a distal occluder on one side and measured with electromagnetic flow probes in both vessels. The results are promising and demonstrate a good correlation between the high-speed CT findings and those measured with the flow probes.
The diagnostic accuracy of ultrafast computed tomography (CT) was evaluated prospectively in 25 infants and children with suspected airway obstruction. All examinations were conducted in spontaneously breathing, nonsedated children. Scan acquisition times were 0.05 or 0.1 second. CT examinations, completed in an average of 10 minutes, routinely included localizing, contiguous sections through the trachea followed by serial images obtained at a rate of 17 per second through regions of interest. Imaging results were correct in 24 of 25 examinations as judged from clinical and surgical data. Ultrafast CT data permitted diagnosis of dynamic changes in airway caliber, small intraluminal polyps, focal tracheal atresia, compressive mediastinal masses, and foreign body obstructions of the major bronchi. Dose measurements showed a maximum skin exposure of 245 mR (0.06 mC/kg) per 0.05-second image. Ultrafast CT provides an accurate, minimally invasive method for dynamic imaging of the airway in nonsedated children.
Magnetic resonance imaging of the lumbar spine was performed in 17 children with acute lymphocytic leukemia (ALL): eight with newly diagnosed ALL, four with ALL in relapse, and five with ALL in remission. Eleven age-matched children were also imaged as controls. The T1 and T2 relaxation times of the bone marrow in the lumbar spine were calculated for all the children. The T1 relaxation times of the bone marrow were as follows (mean +/- standard deviation): newly diagnosed ALL, 968 msec +/- 68; ALL in relapse, 765 msec +/- 19; ALL in remission, 404 msec +/- 135; and age-matched controls, 441 msec +/- 82. T1 relaxation time was statistically significant in differentiating children with newly diagnosed ALL from normal children and from children with ALL in remission. In addition, T1 may be useful in differentiating children with ALL in relapse from children with ALL in remission and from healthy children. T2 was not significantly different among the four groups.
The diagnostic power of the heart volume and the cardiothoracic ratio in congenital heart disease in neonates has been compared. A consecutive series of 130 children with suspicion of heart disease examined radiologically at between 48 h and 15 days of age were followed for 14 +/- 10 months. Of these, 16 (12%) were diagnosed as having congenital heart disease. The number of false positive and negative diagnoses was less for heart volume than for cardiothoracic ratio using +2 SD as limit for pathology. Accuracy, sensitivity and specificity was 84, 75, and 85% respectively for heart volume and 73, 57, and 75% for cardiothoracic ratio. Cases that were false positive with both methods were significantly more often examined between 48 and 72 hours of age indicating that the explanation might be a somewhat late closure of the ductus arteriosus.
The experience from 123 pediatric MRI examinations disclosed several different types of artifacts and age-related variants that could have caused pitfalls in MRI interpretation. Artifacts were caused by metallic objects, patient touching the RF coil, and patient motion. The potential pitfalls are caused by the MRI variant appearances of anatomical structures specific to the growing body. Recommendations concerning preparation and immobilization of children prior to and during MRI examinations to minimize artifacts are given.
A prototype ultrafast cine computed tomographic (CT) scanner, designed specifically for cardiac imaging, was used to evaluate a preliminary series of patients with prior myocardial infarction (n = 21) and a control group without coronary artery disease (n = 5). Multilevel 50-msec CT scan exposures were obtained during peripheral intravenous bolus injections of contrast medium. A comparison was made between cine-CT scans and standard left ventriculographic images in assessing segmental left ventricular motion. Results indicate that cine CT, performed at sufficiently rapid speeds (20 scans per second) to allow useful analysis of regional ventricular wall motion, can provide adequate image quality. Analysis of 110 segments revealed a good correlation (90.9%) between the two techniques in characterizing normal from abnormal regional wall motion. Cine CT, based on this initial study, demonstrates considerable potential for evaluating not only cardiac chamber dimensions but also segmental wall dynamics.
An approach to optimal assessment of cardiac volume in the neonate is described. 117 normal neonates between 0 and 15 days of age have been used to establish normal standards. Different normal ranges must be used for the 1st und 2nd day of life. The elective determination of heart volume should, for optimal differentiation between normal and pathological values, preferably be done after the 2nd day of life and compared with the corresponding normal standards. The volume has been related both to body weight and body surface area (BSA). The relative volume in cm3 per m2 BSA should be avoided in this age-group.
Ten children aged 1 week to 13 years with 12 vascular abnormalities were examined with magnetic resonance imaging (MRI) and other imaging modalities. MRI was the only single non-invasive modality that demonstrated all lesions and their internal structures. The vascular nature of 3 hemangiomas could not be established with MRI alone. No marked differences in MRI appearance was seen in 5 cases with vascular tumors compared with 5 cases with other vascular abnormalities. The status of the blood in the vascular lesions as flowing fast, slow, or not at all was successfully assessed in 9 of the 12 lesions.
The hypothesis that the normal distribution of relative heart volume in the neonatal period is a mixture of two different populations, with different means and variances, has been tested. The definition of the two populations was (i) normally patent ductus and (ii) closed ductus arteriosus. The assumed frequencies of the patency in different age-groups were taken from Gentile et coll. [5]. A material consisting of 100 neonates found to be normal has been analysed radiologically during the first 360 hours after birth. The results strongly supports the hypothesis and explains the large normal range of relative heart volume during the first 48 hours of life.
The CT attenuation of the myocardium varies with the contrast medium concentration of the blood at steady state. The demonstration of myocardial infarcts depends on the differences of CT numbers within the myocardium. In order to make possible objective estimation and measurement of myocardial ischemia the normal regression between CT attenuation of the blood pool and the myocardium has been determined in 13 dogs. The relationship has been applied to 15 dogs with experimental infarcts examined with contrast enhanced CT. The results indicate that this method may be of value in identifying and sizing myocardial infarcts of different ages in patients.
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