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J Rydberg

Publications and source records attributed to J Rydberg.

At least 19 recordsLinked to original sources
PubMed2006

Isotropic chest CT examination: diagnostic quality of reformats.

AIM: To evaluate the image quality of axial and coronal reformats obtained from isotropic resolution 40-channel chest computed tomography (CT) examinations. METHODS AND MATERIALS: Thirty consecutive patients with intravenous contrast-enhanced chest CT examinations using a 40-channel CT machine were enrolled for the study. The raw data were reconstructed into two sets of source axial images: 0.9 mm section width and 0.45 mm reconstruction interval (isotropic resolution) and 4mm section width with 3 mm reconstruction interval (anisotropic resolution; group A). The isotropic data set was reformatted into axial and coronal stacks (groups B and C, respectively) with 4 mm section width and 3 mm interval. Three independent readers evaluated stacks A to C using a three-point scale for resolution of right lower lobe segmental bronchi, edge sharpness of major and minor fissures, respiratory motion artefact, reconstruction artefact, noise and overall image quality. RESULTS: The sharpness of fissures scored significantly higher with the coronal reformats (group C) compared with the axial image sets (groups A and B) (p<0.01). Noise in group A scored significantly lower than groups B or C (p<0.01). For other parameters there was no statistical difference between the groups. There was substantial or excellent agreement between the reviewers. CONCLUSION: Isotropic imaging of the chest allows creation of reformats with similar image quality as similar thickness axial source images. These reformats are probably of sufficient quality to form the basis of clinical interpretation.

Adult↗
PubMed2006

Routine isotropic computed tomography scanning of the abdomen and pelvis.

For 30 years, abdominal CT has been imaged and reviewed in the axial plane. It is now possible to carry out isotropic imaging of the whole abdomen and pelvis using a 40-channel scanner. This allows creation of coronal and sagittal reformats with the same image quality as the axial images. In this study, we present our experience of reviewing routinely coronal and, occasionally, sagittal reformats. We discuss situations where these nonaxial reformats are most beneficial.

Adult↗
PubMed2001

Evaluation of prospective living renal donors for laparoscopic nephrectomy with multisection CT: the marriage of minimally invasive imaging with minimally invasive surgery.

Laparoscopic technique for excision of a kidney from a living donor has advantages over conventional open surgery, but operative visibility and surgical exposure are limited. Preoperative multisection computed tomography (CT) can provide necessary anatomic information in a minimally invasive procedure. A three-phase examination is suggested: (a) imaging from the top of the kidneys to the pubic symphysis with a section width of 2.5 mm and no contrast medium, (b) scanning of the kidneys and upper pelvis during the arterial phase of enhancement with a section width of 1.0 mm, and (c) scanning of the kidneys and upper retroperitoneum during the nephrographic phase of enhancement with a section width of 1.0 mm. Emphasis in this article is placed on analysis of the venous anatomy because most radiologists are unfamiliar with the anatomic variations. Conventional radiography of the abdomen and pelvis is performed after CT to evaluate the collecting system and ureters and to provide a lower total radiation dose than if CT were used. Of several postprocessing techniques that may be used, the authors prefer maximum intensity projection for arterial evaluation and multiplanar reformatting for venous evaluation.

Humans↗
PubMed1998

Frequency of late allergy-like adverse reactions following injection of intravascular non-ionic contrast media. A retrospective study comparing a non-ionic monomeric contrast medium with a non-ionic dimeric contrast medium.

PURPOSE: A retrospective study was undertaken of the late adverse reactions following the injection of contrast media. The purpose was to determine whether there was a difference between non-ionic monomeric (iohexol) and non-ionic dimeric (iodixanol) contrast media in the reactions produced. MATERIAL AND METHODS: A total of 3,408 patients were sent a written questionnaire in which they were asked to confirm or deny any subjective discomfort or adverse event during a period of one hour to one week after a previous radiological examination with contrast medium. Patients who had undergone angiography (i.v. or i.a. injection) and CT (i.v. injection) were included. Objective signs of an allergy-like reaction were listed and the patients were asked to subjectively quantify any consequent discomfort. RESULTS: The compliance rate was 84%. Of the 3075 injections finally included in the study, 133 (4.3%) had resulted in contrast-medium-related adverse reactions of which 72 (2.3%) were immediate and 61 (2%) were late. Iohexol induced late reactions in 14/851 (1.7%) cases, and iodixanol in 24/1218 (2.0%) cases following i.v. injection and in 23/1006 (2.3%) cases following i.a. injection. The differences were not significant. There were no differences between the two contrast media in the subjective rating of discomfort except that the patients who had received iodixanol also had the highest individual-intensity score. No patient had been hospitalized owing to an adverse reaction and all reactions had been regarded as mild or moderate. CONCLUSION: The number of late adverse reactions was low. There was no difference in the frequency of the late adverse reactions following i.v. injection between iodixanol and iohexol. There was also no difference in the reactions between the i.a. and i.v. injections of iodixanol.

Contrast Media↗
PubMed1996

Fusion rate after posterior lumbar interbody fusion with carbon fiber implant: 1-year follow-up of 51 patients.

Problems associated with posterior lumbar interbody fusion (PLIF) have traditionally included the need for donor bone, prolonged healing time of donor bone, the difficulty of cutting precise bony channels, the risk of retropulsion of graft, postoperative collapse of the bone graft, and pseudarthrosis. To avoid these problems a carbon fiber reinforced polymer implant cage has been developed to facilitate interbody fusion. The aim of the present study was to evaluate the technical problems and fusion rate associated with these new device for PLIF. Between April 1991 and December 1993, 65 pairs of these implant cages were sold in Sweden. They were traced to six hospitals, where they had been used in the treatment of 51 patients operated on at a total of 65 levels. All PLIF were supplemented with VSP (Variable Screw Placement) instrumentation. All medical records were evaluated and all patients were examined with plain radiographs taken at least 1 year after surgery. If that investigation did not show a clear fusion they were also evaluated with CT (18 patients, 27 levels). No intraoperative problems with the device have been reported; 44 patients (86%) and 58 levels (89%) achieved successful fusion. All patients bar one maintained their immediately obtained postoperative disc height. CT with 1-mm slices and sagittal reconstruction is most helpful if radiographs are difficult to interpret.

Adult↗
PubMed1996

Postoperative lumbar MR imaging with contrast enhancement. Comparison between symptomatic and asymptomatic patients.

UNLABELLED: PURPOSE AND MATERIAL: Contrast-enhanced MR imaging of the spine after surgery for lumbar disk herniation almost always shows pathologic changes. To investigate to what extent these changes are correlated to patients' actual clinical symptoms, we compared the postoperative MR findings in 19 asymptomatic patients with 42 symptomatic patients (43 levels). METHODS: The asymptomatic patients underwent MR examination one year after surgery. Twenty-six of the symptomatic patients underwent MR one year or less after surgery, and in 16 patients (17 levels) MR was performed more than one year after surgery. RESULTS: Sixteen percent of the asymptomatic and 42% of the symptomatic patients had disk herniation at the level of previous surgery. Most of the herniated disks were found in the symptomatic patients less than one year after surgery. The amount of epidural scar tissue, displacement and thickening of nerve roots, and compression of the dural sac were also studied. Disk herniation as a probable cause of recurrent sciatica was a common finding among symptomatic patients examined one year or less after surgery. In comparing asymptomatic patients and symptomatic patients with more than one year between surgery and MR examination, no significant radiologic differences, including disk herniation, were found.

Adult↗
PubMed1995

Assessment of a possible imbalance between tumor necrosis factor (TNF) and soluble TNF receptor forms in tuberculous infection of the central nervous system.

Distributions of tumor necrosis factor (TNF) and its soluble receptor forms, R55-BP and R75-BP, were analyzed in the cerebrospinal fluid of patients with severe acute or chronic central nervous system infections. Tuberculous infections were associated with high ratios of R55-BP and R75-BP to TNF, 27.2 and 28.0, respectively, suggesting a small biologically active fraction of TNF. The opposite was found in subjects with acute bacterial meningitis. They had large fractions of biologically active TNF and thus low ratios of R55-BP and R75-BP to TNF, 3.7 and 4.0, respectively. It is hypothesized that chronic infectious diseases, such as tuberculous infections, may be associated with inadequate production of TNF and a concomitant relative increase of soluble TNF receptors, which may prolong the disease.

Acute Disease↗
PubMed1995

A large collar increases neck resorption in total hip replacement. 204 hips evaluated during 5 years.

We evaluated the effect of a prosthetic collar on the proximal femoral bone in 204 hips without any signs of loosening after 5 years. The patients were operated on at 5 centers, using different prosthetic designs, but the same cementing technique. Resorption was more often found in cases with a true and large collar (Lubinus, HD2, Scanhip) than in cases with a flanged or tapered stem (Charnley, Exeter). The resorption was also more pronounced with the former designs. It was concluded that, in spite of theoretical advantages, a large collar is not only unnecessary but may also have negative long-term effects.

Analysis of Variance↗
PubMed1994

Comparison of contrast-enhanced computed tomography and gadolinium-enhanced magnetic resonance imaging one year after lumbar discectomy.

Computed tomography (CT) and magnetic resonance imaging (MRI) with intravenous contrast were performed on a prospective group of 35 consecutive patients 1 year after surgery for disc herniation. The aim of the study was to compare the two methods in the analysis of postoperative changes. Computed tomography showed, compared with MRI, more extensive scar tissue in 12 patients and increased deformation of the dural sac in 5 patients. However, the nerve root was better delineated by MRI, and this facilitated the assessment of root thickening in 13 patients and root displacement, which could not be seen by CT in seven patients. MRI revealed four small protrusions that were not visible with CT. The two methods were found to be of equal value in regard to findings such as disc herniations and foraminal stenosis, which might influence the surgeons decision to perform repeat surgery.

Adolescent↗
PubMed1994

Interleukin 6 response to urinary tract infection in childhood.

This study analyzed the interleukin 6 (IL-6) response in 114 children with suspected urinary tract infection (UTI). Urine and serum samples were obtained at the time of enrollment. There were 90 children with UTI, 41 with and 49 without a temperature > or = 38.5 degrees C. The remaining 24 children did not have bacteriuria; 11 were febrile and 13 were not. The urinary IL-6 concentrations were higher in the children with UTI (mean, 129 units/ml) than in the children without bacteriuria (mean, 7 units/ml, P < 0.01). In contrast the serum IL-6 did not differ between children with or without UTI or between children with or without a temperature > or = 38.5 degrees C. The urinary IL-6 response was higher in children who were infected with P fimbriated Escherichia coli than in other children with UTI (P < 0.05). There was a correlation of urinary IL-6 with the degree of proteinuria, hematuria and urinary leukocyte counts (P < 0.001, P < 0.05, P < 0.05, respectively) but not with serum IL-6, CRP or temperature, and of serum IL-6 to C-reactive protein (P = 0.053) and renal concentrating capacity (P < 0.05). The results demonstrate that infections of the urinary tract activate an IL-6 response in children and that the magnitude of the IL-6 response is influenced by the properties of the infecting strain.

Adolescent↗
PubMed1994

Resistance to fluoroquinolones in Pseudomonas aeruginosa and Klebsiella pneumoniae.

The fluoroquinolone sensitivity of Pseudomonas aeruginosa and Klebsiella pneumoniae was studied by determinations of Minimum Inhibitory Concentrations (MICs) of norfloxacin and ciprofloxacin in consecutive clinical isolates. In P. aeruginosa, resistance or reduced susceptibility (MIC > or = 8 mg/l for norfloxacin and > or = 2 mg/l for ciprofloxacin) was found in 17% (9/54) of the isolates. Reduced susceptibility (MIC > or = 2 mg/l for norfloxacin) was found in 12% (10/84) of K. pneumoniae isolates. P. aeruginosa strains isolated in 1991 had reduced susceptibility to both norfloxacin and ciprofloxacin significantly more often than isolates from 1984-85 (p = 0.02). 10/84 K. pneumoniae strains from 1991 had reduced susceptibility to norfloxacin, compared with 1/34 from 1984-85. This difference was not statistically significant (p = 0.11).

Anti-Infective Agents↗
PubMed1994

Intravenous Helicobacter pylori induces low levels of TNF-alpha and IL-1 alpha in a murine model.

A murine model for testing cytokine production stimulated by Helicobacter pylori is described. H. pylori induced significantly lower levels of TNF-alpha and IL-1 alpha compared to Escherichia coli or Pseudomonas aeruginosa when injected intravenously. The mean TNF-alpha concentration in serum during 6 h after stimulation with H. pylori was 0.2 ng/ml, whereas E. coli induced 4.7 ng/ml and P. aeruginosa 6.0 ng/ml. This was not explained by rapid elimination of H. pylori as bacteria were present for at least 3 h in the blood. The difference in cytokine induction may be a reflection of the bacteria's different biological qualities. E. coli and P. aeruginosa are both capable of causing systemic disease, whereas H. pylori causes only a local, often low grade, inflammation in the gastric mucosa.

Animals↗