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At least 523 records · Page 29Linked to original sources
PubMed2003

Prediction of rupture risk in abdominal aortic aneurysm during observation: wall stress versus diameter.

OBJECTIVES: We previously showed that peak abdominal aortic aneurysm (AAA) wall stress calculated for aneurysms in vivo is higher at rupture than at elective repair. The purpose of this study was to analyze rupture risk over time in patients under observation. METHODS: Computed tomography (CT) scans were analyzed for patients with AAA when observation was planned for at least 6 months. AAA wall stress distribution was computationally determined in vivo with CT data, three-dimensional computer modeling, finite element analysis (nonlinear hyperelastic model depicting aneurysm wall behavior), and blood pressure during observation. RESULTS: Analysis included 103 patients and 159 CT scans (mean follow-up, 14 +/- 2 months per CT). Forty-two patients were observed with no intervention for at least 1 year (mean follow-up, 28 +/- 3 months). Elective repair was performed within 1 year in 39 patients, and emergent repair was performed in 22 patients (mean, 6 +/- 1 month after CT) for rupture (n = 14) or acute severe pain. Significant differences were found for initial diameter (observation, 4.9 +/-.1 cm; elective repair, 5.9 +/-.1 cm; emergent repair, 6.1 +/-.2 cm; P <.0001) and initial peak wall stress (38 +/- 1 N/cm(2), 42 +/- 2 n/cm(2), 58 +/- 4 N/cm(2), respectively; P <.0001), but peak wall stress appeared to better differentiate patients who later required emergent repair (elective vs emergent repair: diameter, 3% difference, P =.5; stress, 38% difference, P <.0001). Receiver operating characteristic (ROC) curves for predicting rupture were better for peak wall stress (sensitivity, 94%; specificity,81%; accuracy, 85% [with 44 N/cm(2) threshold]) than for diameter (81%, 70%, 73%, respectively [with optimal 5.5 cm threshold). With proportional hazards analysis, peak wall stress (relative risk, 25x) and gender (relative risk, 3x) were the only significant independent predictors of rupture. CONCLUSIONS: For AAAs under observation, peak AAA wall stress seems superior to diameter in differentiating patients who will experience catastrophic outcome. Elevated wall stress associated with rupture is not simply an acute event near the time of rupture.

Aged↗
PubMed2002

Effect of apolipoprotein E genotype on hematoma volume after trauma.

OBJECT: The apolipoprotein E-epsilon4 (APOE-epsilon4) allele is associated with poor outcome after head injury and spontaneous intracerebral hemorrhage (SICH). The aims of this study were to determine if patients in whom one or more APOE-epsilon4 alleles are present are more likely to sustain intracranial mass lesions after head injury and to determine whether there is an isoform-specific effect on the size of the intracranial hematoma. METHODS: The authors performed a computerized volumetric analysis of 142 hematomas visible on computerized tomography (CT) scans obtained in 129 patients. The APOE genotype was determined by subjecting buccal smear samples to polymerase chain reaction and restriction enzyme digestion. Allele frequencies were similar in head-injured patients with and without intracranial hematomas (p = 0.36). Univariate analysis revealed that in those patients with one or more APOE-epsilon4 alleles hematoma volume was greater (cube root-transformed values) than that found in patients without the APOE-epsilon4 allele (3.1 cm compared with 2.5 cm, p = 0.0039). The results of univariate analysis also suggested significant effects of patient age, injury severity (mild, moderate, or severe according to admission Glasgow Coma Scale scores) and hematoma location (extraaxial, intraaxial, or both) on hematoma volume. The mechanism of injury (assault, fall, or other) was marginally associated with hematoma volume (p = 0.052). Time from injury to CT scan, hypoxia, and hypotension had no significant effect on hematoma volume. The results of multiple linear regression analysis showed that the presence of an APOE-epsilon4 allele and an extraaxial hematoma location were independent predictors of hematoma volume, after adjusting for patient age, hours between injury and CT scan, injury severity, and injury mechanism. CONCLUSIONS: Larger hematomas were found in head-injured patients with one or more APOE-epsilon4 alleles than in patients without the allele. This may contribute to the poorer outcomes observed in these patients.

Adult↗
PubMed2003

Clinical outcomes in patients with suspected acute pulmonary embolism and negative helical computed tomographic results in whom anticoagulation was withheld.

BACKGROUND: Helical computed tomography (CT) techniques for the diagnosis of pulmonary embolism have been refined over the past decade. Helical CT is widely used in the diagnosis of pulmonary embolism despite the lack of well-designed trials supporting this approach. Although helical CT correlates well with pulmonary angiography in detecting central emboli, critics argue that it misses more distal embolic events. It is unknown, however, whether distal emboli are clinically significant. If undetected distal emboli are significant, we reasoned that venous thromboembolic events should occur more often in patients with negative helical CT results who were not receiving anticoagulation. METHODS: We performed a retrospective analysis of 433 sequential helical CT scans ordered for clinical suspicion of pulmonary embolism from March 9, 1999, until April 30, 2002. We excluded 119 studies (27%) that were positive for pulmonary embolism, then excluded 57 others of patients who had received anticoagulation throughout the study period. We then contacted patients and families, and reviewed hospital records and death summaries to determine whether the patients had developed any venous thromboembolic events during the 3-month period following their negative helical CT. RESULTS: Follow-up was completed on 239 (98.4%) of 243 patients. Venous thromboembolic events developed in 4 (1.7%; 95% confidence interval, 0.0%-3.2%). In the 3-month follow-up period, 33 patients died, 1 of a probable pulmonary embolism (0.4% of the study group; 95% confidence interval, 0.0%-1.2%). CONCLUSIONS: Our data support helical CT as a safe, definitive, minimally invasive test that is associated with a low 3-month risk of venous thromboembolism, and may be comparable to results of negative pulmonary angiography or low-probabililty ventilation-perfusion scan.

Acute Disease↗
PubMed1994

Dimensions of the laryngeal framework in adults.

The increasing application of sophisticated electrophysiological, radiological and surgical methods to the diagnosis and treatment of laryngeal disorders requires a profound knowledge of the size and proportions of the human larynx and it's cartilaginous components. Only inadequate data regarding this subject have so far been accessible. The larynges of 53 patients (28 male and 25 female, age 25-88 years, in the means 59 years) were removed during routine autopsy 12-48 h post mortem and immediately submitted to morphometric investigation. None of the patients had histories or visible signs of laryngeal disease. Anatomical preparations were performed with customary surgical tools and morphometric measurements then carried out with a pair of compasses and a calliper rule. A total of 95 measurements were performed on each larynx. These included, aside from evaluation of the whole organ, identification of the internal and external diameters of the cricoid cartilage, height and length of the thyroid alae in different planes, angle of thyroid laminae, height of arytenoid cartilage, width and length of epiglottic cartilage, and internal and external diameter of first tracheal ring. The results obtained provide a full scale of data determining the size and extent not only of it's cartilaginous components, but of the laryngeal framework as a whole. The knowledge of these data may contribute to a precise positioning of electrodes in laryngeal electromyography, to the planning of laryngeal framework surgery, and to the analysis of CT- and MRI-scans of the larynx.

Adult↗
PubMed1994

[Limbus diagnosis by computerized tomography after initial traumatologic dislocation of the shoulder].

This paper shows a retrospective analysis of 98 shoulder joint CT scans after traumatic primary anterior dislocation in the period of 1988 till December 1991. The intraoperative findings and the X-ray characteristics beside arthrographic and MRI examinations led us to a classification of four types by pathomorphologic aspects, the type of the tear correlated to the degree of instability. For anterior limbus tear and lesions, a CT scan gives a diagnostic sensitivity of more than 90% (own rate 94.6%). Concerning our patients, the total lesions rate of 77.6% following first traumatic dislocation justifies a progressive examination and evaluation of the joint structures, that enhance further dislocations. Hereby, inspite of its invasivity, joint CT scan have, in comparison to other diagnostic procedures, proved to be routinely useful.

Adult↗
PubMed2005

[Improved osseointegration of titanium implants after surface coating with polymers in a rabbit model].

In this study we present the first results of the investigation of polymer-coated titanium implants implanted in the proximal tibia and distal femora of New Zealand white rabbits. The results of DEXA scans, micro-CT, and histological analysis showed an increase of osseointegration. We suggest that controlled release kinetics after coupling of these polymers with BMP-2 can additionally increase osseointegration.

Animals↗
PubMed2001

Imaging diagnosis of retroperitoneal ganglioneuroma in childhood.

PURPOSE: To demonstrate the typical appearance of retroperitoneal ganglioneuromas on CT and MRI. MATERIALS AND METHODS: Retrospective analysis of diagnostic imaging (five CT scans, three MRI scans) in five children aged 3-15 years with the histological diagnosis of ganglioneuroma. RESULTS: The scans showed large (maximum 11 cm diameter), round or oval tumours with sharply defined margins. Intraspinal tumour involvement occurred in two cases. Comparing CTwith MRI, MRI was more accurate in defining the intraspinal involvement. The ganglioneuromas were hypodense on unenhanced CT and showed moderate enhancement with administration of contrast medium. In three patients, CT demonstrated tumour calcification with a disseminated speckled pattern. On T1-weighted MRI the tumours were homogeneous and hypointense, showing marked enhancement after gadolinium administration. On T2-weighted scans the tumours were hyperintense. CONCLUSION: At the time of diagnosis, retroperitoneal ganglioneuromas are generally large tumours that can be shown well by CT and MRI. The appearance on CT more readily suggests the diagnosis, but MRI is superior for documenting local or intraspinal tumour extension and lacks radiation load.

Adolescent↗
PubMed2000

Visualisation of the portal flows by porto-scanner.

This study presents a retrospective analysis of 15 portal vein CT scans, conducted for the evaluation of hepatic metastasis in patients suffering from colorectal cancer, with the aim of verifying in vivo the presence of laminar flow as reported by Pironcof. After selective catheterization of the superior mesenteric artery, CT scans were performed during opacification of the portal vein. Different flows were identified by the incomplete opacification they induced in the portal vein. Splenic flows could always be identified, however right colic and superior mesenteric flows were only seen in 3 cases (20%) and gastrocolic flow in 2 (13.6%). Even though incremental (i.e. slower than helical) the CT acquisitions allowed the flows to be viewed by modifying the visualisation window. In vivo evidence of laminar flow is provided which supports Pironcof's experimental observations.

Colorectal Neoplasms↗
PubMed2003

Changes in the proximal neck of abdominal aortic aneurysms early after endovascular treatment.

Long-term success of endovascular treatment of infrarenal abdominal aortic aneurysms (AAA) depends on secure "attachment" of the stent to the proximal and distal necks of the aneurysm. The purpose of this retrospective study was to detect changes in the proximal neck early after endovascular treatment of infrarenal AAA. Between November 1997 and December 1998, we performed endovascular treatment of infrarenal AAA in 43 patients. A bifurcated modular stent (AneuRx by Medtronic) was used in all patients. An oversized stent with a diameter 10% greater than the preoperative diameter of the proximal neck of the AAA was used in all cases. Follow-up examinations were carried out at 1, 6, and 12 months using plain roentgenography, color Doppler ultrasound, and CT scan with contrast injection. Statistical analysis was performed using the Student's t-test. Deterioration of the aortic neck is the result of a variety of mechanisms. The natural history of the infrarenal neck of AAA following endovascular repair (as well as conventional open repair) is progressive enlargement. Stenting could be an added risk factor for expansion. Strict follow-up is essential for early detection of this complication.

Aorta, Abdominal↗
PubMed1994

Pathophysiology and pathogenesis of visceral fat obesity.

Based on the analysis of fat distribution by CT scanning, we have proposed a classification of obesity: visceral fat obesity, in which fat accumulation is predominant in the intra-abdominal cavity. This type of obesity is more frequently accompanied by disorders of glucose and lipid metabolism, and also with hypertension, than subcutaneous fat obesity. We also showed that almost 90% of obese patients with ischemic heart disease have visceral fat accumulation. From clinical and basic experiments, aging, imbalance of sex hormone, overintake of sucrose and lack of physical exercise have been suggested to be major factors for visceral fat accumulation. Since intra-abdominal fat (mesenteric and omentum fat) have been show to have high activities of both lipogenesis and lipolysis, its accumulation induces a high content of free fatty acids, a product of lipolysis, in portal circulation which goes into the liver directly. Excess free fatty acid may cause the enhancement of lipid synthesis and gluconeogenesis as well as insulin resistance, resulting in hyperlipidemia, glucose intolerance and hypertension and finally atherosclerosis.

Adipose Tissue↗
PubMedDate not supplied

Computed tomographic changes in juvenile hemiplegia.

A retrospective analysis of the computer tomographic scans (CT) in 68 patients with juvenile hemiplegia was done. There was predominance of males (60%) over females, as well as left-sided lesions (57%). The CT findings were normal in 15% with atrophic changes in 34%, low attenuation areas of fluid density in 46% and 2.9% (two cases) with tumours. Typical areas of infarction following vascular injuries could be identified in 15% of cases. Six out of 8 calcifications were associated with tuberculoma of the brain. It is noted that cystic changes are the end-results of most infarctions, infections and other diseases within the brain. Therefore, CT as a diagnostic tool is efficacious in determining the anatomical site of lesion, but incapable of elucidating the aetiological basis of such a lesion.

Adolescent↗
PubMed1989

Computed tomographic features of nonthyroid extraocular muscle enlargement.

While Graves' disease is the most common cause of enlarged extraocular muscles, other disorders may masquerade as dysthyroid orbitopathy. The authors conducted a retrospective analysis of the computed tomographic (CT) scans of 60 patients with nonthyroid enlarged extraocular muscles to establish the differential radiographic features of these disorders. The diseases were classified as primary or local invasion of neoplasm (26%), inflammatory (25%), metastatic tumor (20%), vascular (13%), infection (12%), and acromegaly (3%). The inflammatory cases demonstrated more bilateral involvement (40%) and less involvement of the tendons (47%) than previously appreciated. The relatively high incidence of these features in the inflammatory group is important because both features have been considered pathognomonic for Graves' disease. Primary and metastatic tumors produced a nodular muscle enlargement with sharp borders and frequent bone changes. Certain tumors showed a predilection for certain muscle groups. Vascular cases involved multiple unilateral muscles and usually enlarged the superior ophthalmic vein. Infectious cases usually demonstrated fusiform muscle enlargement with blurred margins, whereas acromegaly caused moderate enlargement of all recti. Although certain diagnosis-specific radiographic patterns are described, no feature is pathognomonic for any disorder.

Diagnosis, Differential↗
PubMed2003

Intensity-modulated radiotherapy as a means of reducing dose to bone marrow in gynecologic patients receiving whole pelvic radiotherapy.

PURPOSE: To evaluate intensity-modulated whole pelvis radiotherapy (IM-WPRT) (with bone marrow [BM] as a planning constraint) as a means to reduce the volume of pelvic BM irradiated. METHODS AND MATERIALS: Ten women with cervical or endometrial cancer previously treated using IM-WPRT were selected for this analysis. Using the treatment planning CT scan, the clinical target volume was defined to encompass the gross tumor, parametrial tissues, uterus (if present), and regional lymph nodes. The clinical target volume was expanded by a 1-cm margin to form the planning target volume (PTV). The bladder, rectum, small bowel, and pelvic BM were delineated in each patient. Three plans were created for each patient: a standard four-field WPRT plan, an IM-WPRT treatment plan designed to conform the dose to the PTV while minimizing dose to the normal tissues (excluding BM), and a BM-sparing (BMS) IM-WPRT plan that included the BM as an additional treatment planning constraint. Dose-volume histograms for the PTV, small bowel, and BM were compared for each patient. RESULTS: For each of the 10 patients, BMS IM-WPRT treatment plans demonstrated a significant reduction of the volume of BM receiving >40% (18 Gy) of the prescription dose (45 Gy) compared with both IM-WPRT and four-field treatment. On average, BMS IM-WPRT resulted in only 60% of the BM volume irradiated to >50% of the dose compared with 87.4% (p <0.001) of the BM volume in a four-field plan and 75.7% (p < 0.003) of the volume in an IM-WPRT plan. Furthermore, the BMS IM-WPRT plans resulted in significant sparing of all other normal tissues that was comparable to the original IM-WPRT. In all 10 cases, the BMS IM-WPRT treatment plan did not result in any significant differences in the PTV and small bowel dose-volume histograms compared with the IM-WPRT treatment plans. CONCLUSION: BMS IM-WPRT significantly reduces the volume of pelvic BM irradiated compared with conventional WPRT. In addition, BMS IM-WPRT did not compromise the improvements previously seen in IM-WPRT treatment plans that did not consider BM. Clinical studies are necessary to assess the significance of BMS IM-WPRT in reducing hematologic toxicity.

Bone Marrow Diseases↗
PubMed2001

A prospective evaluation of the use of emergency department computed tomography for suspected acute appendicitis.

BACKGROUND: Computed tomography (CT) is used increasingly to evaluate suspected cases of acute appendicitis (AA) in the emergency department (ED). This prospective study was performed to test the hypothesis that the evaluation of AA by CT in the ED remains suboptimal and that erroneous interpretation diminishes its utility. METHODS: Consecutive patients 18 years of age or older were enrolled prospectively if AA was among the first three differential diagnoses listed in the record of patients undergoing evaluation of abdominal pain in the ED. Imaging of the abdomen and pelvis was obtained at the discretion of the ED staff or consultant surgeon. Initial CT interpretation was by a radiology resident or fellow along with the surgical staff, but final review by an attending radiologist occurred later. Age, gender, presenting symptoms, white blood cell (WBC) count, final CT results, and final pathology (for patients undergoing operation) were recorded. X +/- SEM, p < 0.05 by chi(2), ANOVA, or MANOVA was used for statistical analysis as appropriate. RESULTS: A CT scan was performed in 104 patients (83% of those meeting entry criteria), 35 of whom were male (mean age, 37 +/- 2 years) and 69 of whom were female (mean age, 39 +/- 3 years). Thirty-five patients had pathologically proved appendicitis, 28 of whom were diagnosed prospectively by CT. There were seven false-negative scans. Sensitivity, specificity, and positive predictive value for the initial CT reading were 80%, 91%, and 82%, respectively. Gender (p < 0.03), WBC count (p < 0.0002), and a positive initial CT reading (p < 0.0001) correlated with operative management. However, although final CT interpretation did correlate with pathologic confirmation of AA (p < 0.0001), initial CT interpretation did not correlate with the presence of AA (p = 0.52). CONCLUSION: The ability of CT to predict AA is dependent on the interpretative skill of the individual interpreting the images. Widespread use of CT in the evaluation of patients for AA should be implemented with caution until institution-specific protocols are validated.

Acute Disease↗
PubMed1997

Effect of weight loss on body fat distribution in obese children.

The intra-abdominal visceral fat to subcutaneous fat ratio (V/S ratio) has been reported to be strongly related to disorders of glucose and lipid metabolism, and hypertension. It is a matter of concern as to whether weight loss causes an improvement of the V/S ratio or not in obese children. Changes in body fat distribution during weight loss in 23 obese children were quantified by weight, bioelectrical impedance analysis (BIA) and computed tomography (CT scan of the abdomen). Twenty-three patients were divided into two groups; six were in the inpatient group and 17 were in the outpatient group. Bodyweight, body fat percentage, subcutaneous fat and visceral fat were significantly higher in the inpatient group than in the outpatient group before weight loss. Whereas the V/S ratio was almost equal between the two groups before weight loss. Bodyweight, body fat percentage, subcutaneous fat and visceral fat were found to decrease significantly during weight loss in the two groups. The V/S ratio of the outpatient group did not change after weight loss. In contrast, the V/S ratio of the inpatient group decreased significantly during weight loss. These preliminary findings suggest that a large amount of body fat and a high obesity rate are not always accompanied by a high V/S ratio in obese children. The fat pattern changes during weight loss with strict dietary therapy and therapeutic exercise. A larger sample of obese children should be studied to test this conjecture.

Abdomen↗
PubMed1994

Transient blindness in pregnancy induced hypertension.

Sudden blindness in pregnancy is a devastating experience for the patient, her family and the treating obstetrician. Four cases of cortical blindness with pregnancy induced hypertension are presented, seen at the General Hospital Kota Bharu, Kelantan, in 1990. The incidence at the GHKB was 1: 1559 (4 cases out of 6,237 deliveries) which is higher as compared to neighbouring Singapore. The pathophysiology of this condition is still not well understood, though it is hoped that newer sophisticated imaging techniques like magnetic resonance imaging (MRI), CT scan, and blood flow waveform analysis by Doppler ultrasound will throw some light on the subject. Two of our cases presented with antepartum and two with postpartum cortical blindness. Therefore, termination of pregnancy alone may not provide the solution to this therapeutic dilemma.

Abortion, Therapeutic↗
PubMed1995

Pathophysiology and pathogenesis of visceral fat obesity.

Based on the analysis of fat distribution by CT scanning, we have proposed a classification of obesity--visceral fat obesity--in which fat accumulation is predominant in the intraabdominal cavity. This type of obesity is more frequently accompanied by disorders of glucose and lipid metabolism and also with hypertension than subcutaneous fat obesity. We also showed that visceral fat obesity was present in almost 90% of obese patients with ischemic heart disease. From clinical and basic experiments, aging imbalance of sex hormone, overintake of sucrose, and lack of physical exercise have been suggested to be major factors for visceral fat accumulation. Since intraabdominal fat (mesenteric and omentum fat) have been shown to have high activities of both lipogenesis and lipolysis, its accumulation induces high contents of free fatty acids, a product of lipolysis, in portal circulation which goes into the liver directly. Excess free fatty acid may cause the enhancement of lipid synthesis and gluconeogenesis as well as insulin resistance, resulting in hyperlipidemia, glucose intolerance, and hypertension and finally atherosclerosis.

Abdomen↗
PubMed2002

Longitudinal follow-up study of smoker's lung with thin-section CT in correlation with pulmonary function tests.

PURPOSE: To evaluate thin-section computed tomography (CT) in depicting longitudinal changes in the lung parenchyma. MATERIALS AND METHODS: One hundred eleven volunteers underwent sequential examination with thin-section CT and pulmonary function tests over a mean period of 5.5 years. According to their smoking habits between initial evaluation (T0) and follow-up (T1), the subjects were classified as persistent current smokers (n = 57), persistent nonsmokers (n = 31), persistent ex-smokers (n = 13), or quitters (n = 10). RESULTS: Significant differences in CT findings between T0 and T1 were seen in only the group of persistent current smokers, who showed a higher frequency of emphysema (40% vs 26%; P =.005) and ground-glass attenuation (42% vs 28%; P =.02). Individual analysis of follow-up CT scans in the 19 persistent current smokers with micronodules at T0 demonstrated (a) no changes in seven cases, (b) a higher profusion of micronodules in seven cases, and (c) replacement of micronodules with emphysema in five cases. Subjects with emphysema and/or areas of ground-glass attenuation at T0 had a significantly more rapid decline in lung function than did those with a normal CT scan. CONCLUSION: Emphysema and/or ground-glass attenuation are linked with impairment of ventilatory lung function over time in persistent current smokers.

Adult↗