Biomedical subjects
L Kreel
Publications and source records attributed to L Kreel.
Asymptomatic cerebral calcification--a previously unrecognized feature.
While investigating the radiological appearances of globus pallidus calcification in an autopsy case, cortical-pia mater calcification was detected. There was no documentation of its existence in the literature of radiology, neurology and neuropathology. To establish its incidence and clinical significance, 20 consecutive autopsy brains (15 males, 5 females, age 32-73 years, mean age 56.7) were studied with high resolution radiography and histology. Clinical records, autopsy findings, in-life plain skull films and computed tomography of the brain (if available) were reviewed. Radiologically, the calcifications appeared as 1-2 mm irregular spots or tiny pin-point opacities in the pia mater and subcortical regions, either unilaterally or bilaterally in the frontal (15 cases), temporal (15), parietal (3) and occipital lobes (1). Similar calcification was detected in 1 of the 3 in-life computed tomographic scans available. Histologically, these cortical-pia mater calcifications were extracellular amorphous calcified masses of various sizes in necrotic neural tissue, frequently associated with microscopic haemorrhage and hypoxic neuronal changes in the adjacent brain tissue. Blood vessels in the region were not hyalinized or calcified. The occurrence was not related to age. Hospital stay was less than 7 days in 14 and less than 30 days in 2; 50% of patients died within 48 hours after admission. None of the patients had records of long term cytotoxic chemotherapy, radiotherapy or central nervous system infection. Two had stroke, one had cerebellar atrophy and one mild hypercalcaemia. The high incidence of calcifications in the temporal lobes, while asymptomatic, suggests that cortical calcification may be a pointer to the aetiology of idiopathic epilepsies in the elderly.
Medical imaging.
There is now a wide choice of medical imaging to show both focal and diffuse pathologies in various organs. Conventional radiology with plain films, fluoroscopy and contrast medium have many advantages, being readily available with low-cost apparatus and a familiarity that almost leads to contempt. The use of plain films in chest disease and in trauma does not need emphasizing, yet there are still too many occasions when the answer obtainable from a plain radiograph has not been available. The film may have been mislaid, or the examination was not requested, or the radiograph had been misinterpreted. The converse is also quite common. Examinations are performed that add nothing to patient management, such as skull films when CT will in any case be requested or views of the internal auditory meatus and heal pad thickness in acromegaly, to quote some examples. Other issues are more complicated. Should the patient who clinically has gall-bladder disease have more than a plain film that shows gall-stones? If the answer is yes, then why request a plain film if sonography will in any case be required to 'exclude' other pathologies especially of the liver or pancreas? But then should cholecystography, CT or scintigraphy be added for confirmation? Quite clearly there will be individual circumstances to indicate further imaging after sonography but in the vast majority of patients little or no extra information will be added. Statistics on accuracy and specificity will, in the case of gall-bladder pathology, vary widely if adenomyomatosis is considered by some to be a cause of symptoms or if sonographic examinations 'after fatty meals' are performed. The arguments for or against routine contrast urography rather than sonography are similar but the possibility of contrast reactions and the need to limit ionizing radiation must be borne in mind. These diagnostic strategies are also being influenced by their cost and availability; purely pragmatic considerations are not infrequently the overriding factor. Non-invasive methods will be preferred, particularly sonography as it is far more acceptable by not being claustrophobic and totally free of any known untoward effects. There is another quite different but unrelated aspect. The imaging methods, apart from limited exceptions, cannot characterize tissues as benign or malignant, granulomatous or neoplastic; cytology or histology usually provides the answer. Sonography is most commonly used to locate the needle tip correctly for percutaneous sampling of tissues. Frequently sonography with fine needle aspiration cytology or biopsy is the least expensive, safest and most direct route to a definitive diagnosis. Abscesses can be similarly diagnosed but with needles or catheters through which the pus can be drained. The versatility and mobility of sonography has spawned other uses, particularly for the very ill and immobile, for the intensive therapy units and for the operating theatre, as well in endosonography. The appointment of more skilled sonographers to the National Health Service could make a substantial contribution to cost-effective management of hospital services. Just when contrast agents and angiography have become safe and are performed rapidly, they are being supplanted by scanning methods. They are now mainly used for interventional procedures or of pre-operative 'road maps' and may be required even less in the future as MRI angiography and Doppler techniques progress. MRI will almost certainly extent its role beyond the central nervous system (CNS) should the equipment become more freely available, especially to orthopaedics. Until then plain films, sonography or CT will have to suffice. Even in the CNS there are conditions where CT is more diagnostic, as in showing calculations in cerebral cysticercosis. Then, too, in most cases CT produces results comparable to MRI apart from areas close to bone, structures at the base of the brain, in the posterior fossa and in the spinal cord. Scintigraphy for pulmonary infarcts and bone metastases and in renal disease in children plays a prominent role and its scope has increased with new equipment and radionuclides. Radio-immunoscintigraphy in particular is likely to expand greatly not only in tumour diagnosis but also in metabolic and infective conditions. Whether the therapeutic implications will be realized is more problematic. The value of MRS and NM for metabolic studies in clinical practice is equally problematical, although the data from cerebral activity are extremely interesting. While scanning has replaced many radiographic examinations, endoscopy has had a similar effect on barium meals and to a lesser extent on barium enemas. The combined visual/sonographic endoscope is likely to accelerate this process. There is no doubt that over the last 2 decades medical imaging has changed the diagnostic process, but its influence on the outcome of disease other than infections is less certain and probably indefinable. Data concerning the comparative efficacy in terms of patient outcome for each of the imaging techniques would be of considerable interest and a great help in determining diagnostic strategies.
Post-splenectomy nodules.
Explore the source record for details and available documents.
Hypertension, lipoprotein(a), and apolipoprotein A-I as risk factors for stroke in the Chinese.
We analyzed the serum concentrations of lipids and lipoproteins and the prevalence of other risk factors in a case-control study of 304 consecutive Chinese patients with acute stroke (classified as cerebral infarction, lacunar infarction, or intracerebral hemorrhage) and 304 age- and sex-matched controls. For all strokes we identified the following risk factors: a history of ischemic heart disease, diabetes mellitus, or hypertension; the presence of atrial fibrillation or left ventricular hypertrophy; a glycosylated hemoglobin A1 concentration of greater than 9.1%; a fasting plasma glucose concentration 3 months after stroke of greater than 6.0 mmol/l; a serum triglyceride concentration 3 months after stroke of greater than 2.1 mmol/l; and a serum lipoprotein(a) concentration of greater than 29.2 mg/dl. We found the following protective factors: a serum high density lipoprotein-cholesterol concentration of greater than 1.59 mmol/l and a serum apolipoprotein A-I concentration of greater than or equal to 106 mg/dl. The patterns of risk factors differed among the three stroke subtypes. When significant risk factors were entered into a multiple logistic regression model, we found a history of hypertension, a high serum lipoprotein(a) concentration, and a low apolipoprotein A-I concentration to be independent risk factors for all strokes. The attributable risk for hypertension was estimated to be 24% in patients aged greater than or equal to 60 years. In this population, in which cerebrovascular diseases are the third commonest cause of mortality, identification of risk factors will allow further studies in risk factor modification for the prevention of stroke.
The radiological (CT) and clinical sequelae of primary intracerebral haemorrhage.
To determine the radiological and clinical outcome of primary intracerebral haemorrhage, a prospective study was carried out involving computed tomography (CT) of 388 consecutive Chinese patients admitted with acute stroke to a large public hospital in Hong Kong. Further CT and functional assessment were performed 3 months later in 71% of survivors. The patients were admitted over a 6 month period. 120 (31%) were found to have had presumed primary intracerebral haemorrhage. Of these, 64 patients (53%) died within 3 months. From 40 of the 56 survivors who returned for a follow-up study at 3 months, 30 were functionally independent and five mildly disabled; only five were significantly disabled. Follow-up CT showed no residual lesion in 27%, low attenuation areas in 37%, slit-like lesions in 25% and calcification in 10% of patients. The size of residual lesions correlated statistically with the degree of residual disability, although the association was not close. It is concluded that primary intracerebral haemorrhage accounts for a high percentage of strokes among Hong Kong Chinese with more than half of the patients dying within 3 months. Many survivors, in whom follow-up CT appearances are variable, show good functional recovery.
Computed tomography contrast enhancement of cervical lymphadenopathy.
In a prospective study of 51 cases of lymphadenopathy (44 with cervical metastatic nasopharyngeal carcinoma, NPC) using intravenous contrast and computed tomography (CT), a ring enhancement was observed. A retrospective review of 105 cervical carcinomatous lymph nodes (64 with metastatic NPC) showed a prominent peripheral hypervascular pattern not seen in 48 lymphomas and 60 normal controls. We conclude that in carcinomatous cervical lymphadenopathy, enhancement can be achieved by intravenous contrast and CT; and the peripheral hypervascularity is the anatomical basis for the ring appearances seen radiographically.
Demonstration of Lipiodol in paraffin sections using a modified silver impregnation technique.
To demonstrate postangiographic Lipiodol (LIP) in hepatocellular carcinoma (HCC) in paraffin sections, direct impregnation of formalin-fixed tissue blocks with silver nitrate (AgNO3) was followed by routine processing. LIP appeared as black globules in the sinusoids. Ninety-four tissue blocks from 13 postangiographic LIP HCCs and 69 from 8 non-LIP HCCs and 4 fatty livers were studied. Seventy-two of 73 negative controls and all positive blocks as seen on soft tissue radiographs (STRs) were correctly coded (specificity 98.6%, sensitivity 100%). Twenty-six of the 44 LIP-negative areas on STRs from LIP cases contained scanty globules of less than 10 microns in diameter. Fatty change gave no positive readings. Thus, modified AgNO3 impregnation is a simple, accurate means of detecting LIP in high-quality paraffin sections suitable for tumor diagnosis and, if applied to postangiographic LIP, ultrasonographically guided liver biopsy, can verify that a biopsy has reached a suspected tumor focus.
Unilateral proptosis.
A male aged 19 presented with a protruding left eye increasing slowly for 3 years. On examination there was proptosis and downward displacement of the eye globe.
Pulmonary varix--pathognomonic appearance.
Explore the source record for details and available documents.