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Biomedical subjects

A Hemmingsson

Publications and source records attributed to A Hemmingsson.

At least 91 records · Page 5Linked to original sources
PubMed1981

Perceptibility of experimental and clinical lesions in the CT image with and without image processing.

The Ohio-Nuclear Delta 50 FS whole-body CT scanner and image filtering programs FI and SP:SMOOTH provided with the equipment were used to investigate how the perceptibility in the CT image of artificial lesions in a phantom and of liver lesions in patients was influenced by different reconstruction diameters, radiation doses and section thicknesses and by image filtering and different conditions of viewing. The perceptibility of both artificial and clinical lesions was considerably improved, especially in scans with a low radiation dose, when optimum viewing conditions and image filters were used.

Filtration↗
PubMed1981

Diagnosis of endocrine gastrointestinal tumours.

In 32 patients with endocrine gastrointestinal tumours angiography, CT, ultrasound examination, and in some cases phlebography with blood sampling for hormone analyses were compared with respect to diagnosis of the primary tumour and possibly existing liver metastases. Primary tumours in the pancreas and liver metastases could be diagnosed with CT and ultrasound, except for two small insulinomas, which required angiography.

Adenoma, Islet Cell↗
PubMed1981

Computed tomography of recurrent rectal carcinoma.

Computed tomography was performed in 28 patients and gave a correct diagnosis in 21 of 22 cases with abdomino-perineal excision of the rectum and in 5 of 6 with anterior resection. CT is of considerable value in the diagnosis of local recurrence of rectal carcinoma, particularly after rectal excision.

Aged↗
PubMed1981

Computed tomography, ultrasonography and gamma camera scintigraphy after renal transplantation.

In routine postoperative observations on 31 transplanted kidneys, computed tomography (CT), ultrasonography (US) and gamma scintigraphy (GS) were compared with respect to diagnosis of abscess or lymphocele in the vicinity of the transplant, rejection and outflow obstruction. The results showed that US was the most reliable procedure for detecting fluid-filled cavities. In cases of graft rejection, GS was of most value. In demonstrating outflow obstruction, there was no definite difference between the three methods.

Cysts↗
PubMed1981

Haemorrhage into a pheochromocytoma in an anticoagulant-treated patient.

Bleeding in a pheochromocytoma after anticoagulant therapy is described. The symptomatology, diagnosis, treatment and prognosis are surveyed. The importance of computed tomography, possibly with the addition of angiography, in the diagnosis of this rare condition is emphasized.

Adrenal Gland Neoplasms↗
PubMed1981

Preoperative evaluation of abdominal aortic aneurysms: is there a need for aortography?

A comparison was made between angiography (AI), computer tomography (CT) and ultrasound (US) in the preoperative evaluation of 85 consecutive patients with abdominal aortic aneurysm. A total of 63 AI, 24 CT and 43 US were performed. It is concluded that the diagnostic accuracy in identifying aneurysms is higher for CT and US than for AI. AI and CT provide more correct data concerning the anatomy in the region of the renal arteries than US. We suggest that a non-invasive technique should be used for preoperative verification of the diagnosis. AI should only be used when the upper limit of the aneurysm and the relation to the renal arteries cannot be defined by non-invasive methods and, furthermore, in all cases with clinical signs of stenotic disease of the iliac arteries.

Adult↗
PubMed1980

Pulmonary pseudotumours and asbestos.

Ten patients are described in whom a localized reaction in the visceral pleura developed comparatively rapidly, involving parts of the underlying lung parenchyma, forming an atelectatic pseudotumour. The lesions were mistaken for pulmonary malignancy, leading to thoracotomy in 5 patients. It is suggested that these lesions can occur many years after exposure to asbestos and that they are sequelae of benign pleurisy. Computer tomography is of great value in these cases and may obviate thoracotomy.

Adult↗
PubMed1980

Percutaneous nephropyelostomy. A new technique.

Percutaneous nephropyelostomy was carried out in 33 patients with a modified technique. The puncture was performed under control by dynamic ultrasound with a sector-scanner using a needle guide unit fitted to the transducer head and primary insertion of a wide-bore catheter. After 2 days the catheter could be replaced by a balloon catheter for permanent or temporary drainage.

Adult↗
PubMed1980

Computed tomography in staging of bladder carcinoma.

A comparison was made between the use of clinical methods and computed tomography for staging of carcinoma of the urinary bladder in 52 patients. CT was found to be the most reliable method for determining the perivesical extension of the tumour. It is of value for determining the extent of the tumour before irradiation and for establishing the tumour response. It was less reliable for diagnosing metastases in the lesser pelvis.

Carcinoma↗
PubMed1980

Noise and noise texture in CT images before and after post-processing.

Two homogeneous water phantoms were recorded under various CT scanner settings, and the reducing effect of various convolution filters on the noise level was evaluated. The change in noise texture introduced by the filtering process was assessed for a limited range of scanner settings by noise analysis of the autocovariance matrix before and after filtering. The results indicate that reduction of noise expressed as RMSD by a factor of about 8 is possible with the filters available in the software package of the Ohio-Nuclear Delta 50 FS tomograph, with some sacrifice in spatial resolution. Results of preliminary experiments with an inhomogeneous phantom are in agreement with this finding and indicate that filtering allows smaller lesions to be detected.

Computers↗
PubMed1980

Diagnosis of abdominal aortic aneurysms by aortography, computer tomography and ultrasound.

Aortography, computer tomography and ultrasound were compared with respect to the diagnosis and evaluation of abdominal aortic aneurysms. The results show that ultrasound should be the method of choice for diagnosis and that the extension of the aneurysm towards the renal arteries is best evaluated by computer tomography. Aortography can thus be omitted in most cases.

Aorta, Abdominal↗
PubMed1980

Modification of grey scale in computer tomographic images.

Optimum perception of minute but relevant attenuation differences in CT images often requires display window settings so narrow that a considerable fraction of the image appears completely black or white and consequently without structure. In order to improve the display characteristics two principles of grey scale modification are presented. In one method the pixel contents are displayed unchanged within a selectable attenuation band but moved towards the limits of the band for pixels that are outside it. In the other the grey scale is arranged to a constant number of pixels per grey scale interval.

Humans↗
PubMed1979

Image enhancement by digital-analog filtration. II. Tests of filters.

The function of a device for frequency filtration of roentgenograms with digital filters has been tested with the use of different filters. The image was altered in the expected way, which means that the device is suitable for investigating the possibilities of different filters to improve the diagnostic ability. The results of the tests indicate that improvement should be achieved by low-pass filtration.

Femur↗
PubMed1979

Image enhancement by digital-analog filtration. I. Technical description of device.

A device for general (10 x 10 pixels) image filtration of 24 cm x 30 cm roentgenograms in the image domain (10(6) pixels) is described. It combines analog and digital techniques and records the processed image on film in the same scale as the original. Results from preliminary tests of the equipment are reported and it is concluded that it yields images with increased perceptibility of large-scale objects of low photographic contrast in the presence of disturbing structures of high spatial frequency and comparably high photographic contrast.

Bone and Bones↗
PubMed1979

Computed tomography of the ankle.

Transverse computed tomography of injured ankles gives additional information compared with conventional roentgen diagnostic techniques. In transverse sections the distal tibio-fibular joint and the suprasyndesmotic region can be examined with regard to incongruence and synostoses. It is also possible to examine the relations between the talus and the malleolar facets in different ankle positions. The technical problems and advantages are discussed.

Ankle Injuries↗