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1.
Abdom Radiol (NY) ; 47(1): 184-195, 2022 01.
Article in English | MEDLINE | ID: mdl-34677624

ABSTRACT

PURPOSE: The purposes of this study are (1) to utilize multivariable logistic regression in order to evaluate which image feature combination is most predictive in the diagnosis of cholecystitis for computed tomography (CT) and ultrasound (US) in adult ED patients and (2) to use these results to compare the accuracy of CT and US. METHODS: For RUQ pain patients undergoing US and CT at the same visit, multiple image features were evaluated independently by 2 radiologists blinded to additional data. Inter-reader variability was measured with the Kappa statistic. Sonographic Murphy's sign (SMS) information was obtained from original reports. Multivariable logistic regression was utilized to develop optimal predictive models for each modality. For US, models with/without SMS were compared to establish its relative value. RESULTS: 446 patients met inclusion criteria. For CT, the combination of cholelithiasis, short-axis gallbladder diameter > 3 cm, pericholecystic fluid or inflammation, and mural thickening > 3 mm provided the optimal model for both readers. For US, the optimal model included cholelithiasis, short-axis diameter > 3 cm, mural heterogeneity/striation, and sludge/debris for both readers. Kappa = 0.79-0.96 for included image features. For both readers, CT and US models had equivalent diagnostic performances; the SMS did not contribute significantly to US models. CONCLUSION: For a diagnosis of cholecystitis in the ED, (1) the optimal image feature combination for CT is cholelithiasis, short-axis diameter > 3 cm, pericholecystic fluid or inflammation, mural thickening > 3 mm; and cholelithiasis, short-axis diameter > 3 cm, mural heterogeneity/striation, sludge/debris for US; (2) CT and US have equivalent diagnostic performance; (3) inter-reader reliability is substantial to excellent for utilized image features; (4) the SMS does not affect US model accuracy.


Subject(s)
Cholecystitis , Adult , Cholecystitis/diagnostic imaging , Humans , Reproducibility of Results , Retrospective Studies , Tomography, X-Ray Computed , Ultrasonography
2.
HIV Med ; 22(8): 715-722, 2021 09.
Article in English | MEDLINE | ID: mdl-34003565

ABSTRACT

BACKGROUND: There are few data on the prevalence of gestational diabetes (GDM) in pregnant women living with HIV (WLHIV) in sub-Saharan Africa, particularly those using integrase strand transfer inhibitors such as dolutegravir (DTG). METHODS: We prospectively enrolled pregnant WLHIV and pregnant women without HIV ≥18 years old in Gaborone, Botswana, excluding those with pre-existing diabetes. We screened for GDM using a 75 g oral glucose tolerance test (OGTT) performed at 24-28 weeks' gestation or at the earliest prenatal visit for those presenting after 28 weeks. Logistic regression models were fitted to assess the association between maternal HIV infection and GDM. Subgroup analyses were performed among WLHIV to assess the association between maternal antiretroviral therapy (ART) in pregnancy [DTG vs. efavirenz (EFV) with tenofovir/emtricitabine] and GDM. RESULTS: Of 486 pregnant women, 66.5% were WLHIV, and they were older than women without HIV (median age 30 vs. 25 years, P < 0.01). Among WLHIV, 97.8% had an HIV-1 RNA level < 400 copies/mL at enrolment. Overall, 8.4% had GDM with similar rates between WLHIV and those without HIV (9.0% vs. 7.4%). The WLHIV receiving DTG-based ART had a 60% lower risk for GDM compared with those on EFV-based ART (adjusted odds ratio = 0.40, 95% CI: 0.18-0.92) after adjusting for confounders. CONCLUSIONS: Pregnant WLHIV on ART in Botswana were not at increased risk of GDM compared with women without HIV. Among WLHIV, the risk of GDM was lower with DTG- than with EFV-based ART. Further studies with larger cohorts are warranted to confirm these findings.


Subject(s)
Diabetes, Gestational , HIV Infections , Adolescent , Adult , Alkynes , Benzoxazines/adverse effects , Botswana/epidemiology , Cyclopropanes , Diabetes, Gestational/chemically induced , Diabetes, Gestational/drug therapy , Diabetes, Gestational/epidemiology , Female , HIV Infections/complications , HIV Infections/drug therapy , Heterocyclic Compounds, 3-Ring , Humans , Oxazines , Piperazines , Pregnancy , Pyridones
3.
Abdom Radiol (NY) ; 46(7): 3519-3520, 2021 07.
Article in English | MEDLINE | ID: mdl-33666736
4.
Magn Reson Med ; 85(1): 518-530, 2021 01.
Article in English | MEDLINE | ID: mdl-32738073

ABSTRACT

PURPOSE: To use fiducial markers containing manganese 55 to rapidly localize carbon 13 (13 C) RF coils for correcting images for B1 variation. METHODS: Hollow high-density polyethylene spheres were filled with 3M sodium permanganate and affixed to a rectangular 13 C-tuned RF coil. The relative positions of the markers and coil conductors were mapped using CT. Marker positions were measured by MRI using a series of 1D projections and automated peak detection. Once the coil location was determined, coil sensitivity was estimated using a quasi-static calculation. Simulations were performed to determine the minimum number of projections required for robust localization. Phantom experiments were used to confirm the accuracy of marker localization as well as the calculated coil sensitivity. Finally, in vivo validation was performed using hyperpolarized 13 C pyruvate in a rat model. RESULTS: In simulations, our algorithm was accurate in determining marker positions when at least 6 projections were used (RMSE 1.4 ± 0.9 mm). These estimates were verified in phantom experiments, where markers locations were determined with an RMS accuracy of 1.3 mm. A minimum SNR of 4 was required for automated detection to perform accurately. Computed coil sensitivity had a median error of 17% when taken over the entire measured area and 5.7% over a central region. In a rat, correction for nonuniform reception and flip angle was able to normalize the signals arising from asymmetrically positioned kidneys. CONCLUSION: Manganese 55 fiducial markers are an inexpensive and reliable method for rapidly localizing 13 C RF coils and correcting 13 C images for B1 variation without user intervention.


Subject(s)
Fiducial Markers , Magnetic Resonance Imaging , Algorithms , Animals , Phantoms, Imaging , Radio Waves , Rats
5.
AJR Am J Roentgenol ; 214(6): 1305-1310, 2020 06.
Article in English | MEDLINE | ID: mdl-32160055

ABSTRACT

OBJECTIVE. The purpose of this study was to compare ultrasound and CT in the diagnostic evaluation of right upper quadrant pain in adults in the emergency department. MATERIALS AND METHODS. A retrospective review was conducted of adult emergency department encounters for right upper quadrant pain over a 5-year period, excluding those for prior cholecystectomy, current pregnancy, and trauma. Imaging study reports were reviewed for gallbladder and nongallbladder explanations of right upper quadrant pain and were considered positive for cholecystitis when two or more supportive features were present. Encounter outcomes were evaluated on the basis of pathology data and clinical management. RESULTS. Among the encounters, 2859 met the study inclusion criteria, and 18% met the study definition of cholecystitis by pathologic or clinical criteria. The following metrics showed no statistically significant difference between ultrasound and CT, respectively: sensitivity, 61% and 55%; specificity, 91% and 92%; positive predictive value, 63% and 63%; and negative predictive value, 91% and 90%. Both modalities were performed in 20% of encounters. In the subgroup analysis, ultrasound showed an acute nongallbladder abnormality that was missed at a preceding CT examination in only 1 of 238 cases (0.4%). CT showed an acute nongallbladder abnormality missed at a preceding ultrasound examination in 103 of 322 cases (32%). CONCLUSION. CT is noninferior to ultrasound in both ruling in and ruling out the diagnosis of cholecystitis in adult patients undergoing emergency evaluation of right upper quadrant pain and offers the advantage of depicting acute nongallbladder abnormalities.


Subject(s)
Abdominal Pain/diagnostic imaging , Cholecystitis/diagnostic imaging , Emergency Service, Hospital , Tomography, X-Ray Computed/methods , Ultrasonography/methods , Adolescent , Adult , Aged , Aged, 80 and over , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Retrospective Studies , Sensitivity and Specificity
6.
Radiographics ; 39(7): 2040-2052, 2019.
Article in English | MEDLINE | ID: mdl-31603734

ABSTRACT

The high prevalence of thyroid nodules combined with the generally indolent growth of thyroid cancer present a challenge for optimal patient care. Risk classification models based on US features have been created by multiple professional societies, including the American College of Radiology (ACR), which published the Thyroid Imaging Reporting and Data System (TI-RADS) in 2017. ACR TI-RADS uses a standardized lexicon for assessment of thyroid nodules to generate a numeric scoring of features, designate categories of relative probability of benignity or malignancy, and provide management recommendations, with the aim of reducing unnecessary biopsies and excessive surveillance. Adopting ACR TI-RADS may require practice-level changes involving image acquisition and workflow, interpretation, and reporting. Significant resources should be devoted to educating sonographers and radiologists to accurately recognize features that contribute to the scoring of a nodule. Following a system that uses approved terminology generates reproducible and relevant reports while providing clarity of language and preventing misinterpretation. Comprehensive documentation facilitates quality improvement efforts. It also creates opportunities for outcome data and other performance metrics to be integrated with research. The authors review ACR TI-RADS, describe challenges and potential solutions related to its implementation based on their experiences, and highlight possible future directions in its evolution. ©RSNA, 2019 See discussion on this article by Hoang.


Subject(s)
Radiology , Research Design , Thyroid Gland/diagnostic imaging , Thyroid Neoplasms/diagnostic imaging , Thyroid Nodule/diagnostic imaging , Ultrasonography , Biopsy, Fine-Needle , Disease Management , Elasticity Imaging Techniques , Forecasting , Humans , Medical Overuse , Prevalence , Procedures and Techniques Utilization , Quality Improvement , Radiology/education , Reproducibility of Results , Research Design/standards , Risk Assessment , Societies, Medical , Thyroid Gland/pathology , Thyroid Neoplasms/epidemiology , Thyroid Nodule/classification , Thyroid Nodule/epidemiology , Thyroid Nodule/pathology , Ultrasonography/methods , Ultrasonography/standards , Unnecessary Procedures , Workflow
9.
HIV Med ; 19(3): 175-183, 2018 03.
Article in English | MEDLINE | ID: mdl-29159965

ABSTRACT

OBJECTIVES: Dyslipidaemia is common in perinatally HIV-infected (PHIV) youth receiving protease inhibitors (PIs). Few studies have evaluated longitudinal lipid changes in PHIV youth after switch to newer PIs. METHODS: We compared longitudinal changes in fasting lipids [total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and TC:HDL-C ratio] in PHIV youth enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS) Adolescent Master Protocol (AMP) study who switched to atazanavir/ritonavir (ATV/r)- or darunavir/ritonavir (DRV/r)-based antiretroviral therapy (ART) from an older PI-based ART and those remaining on an older PI. Generalized estimating equation models were fitted to assess the association of a switch to ATV/r- or DRV/r-based ART with the rate of change in lipids, adjusted for potential confounders. RESULTS: From 2007 to 2014, 47 PHIV children/adolescents switched to ATV/r or DRV/r, while 120 remained on an older PI [primarily lopinavir/r (72%) and nelfinavir (24%)]. Baseline age ranged from 7 to 21 years. After adjustment for age, Tanner stage, race/ethnicity, and HIV RNA level, a switch to ATV/r or DRV/r was associated with a more rapid annual rate of decline in the ratio of TC:HDL-C. (ß = -0.12; P = 0.039) than remaining on an older PI. On average, TC declined by 4.57 mg/dL/year (P = 0.057) more in the switch group. A switch to ATV/r or DRV/r was not associated with the rate of HDL-C, LDL-C, or TG change. CONCLUSIONS: A switch to ATV/r or DRV/r may result in more rapid reduction in TC and the TC:HDL-C ratio in PHIV youth, potentially impacting long-term cardiovascular disease risk.


Subject(s)
Atazanavir Sulfate/therapeutic use , Darunavir/therapeutic use , Dyslipidemias/metabolism , HIV Infections/drug therapy , HIV Protease Inhibitors/therapeutic use , Lipids/analysis , Ritonavir/therapeutic use , Adolescent , Child , Cohort Studies , Drug Therapy, Combination , Dyslipidemias/chemically induced , Female , HIV-1/drug effects , Humans , Longitudinal Studies , Male , Viral Load/drug effects , Young Adult
10.
Radiographics ; 37(7): 2063-2082, 2017.
Article in English | MEDLINE | ID: mdl-29131768

ABSTRACT

Abdominal and pelvic hernias may be indolent and detected incidentally, manifest acutely with pain and distress, or cause chronic discomfort. Physical examination findings are often ambiguous and insufficient for optimal triage. Therefore, accurate anatomic delineation and identification of complications are critical for effective treatment planning. Imaging, particularly computed tomography, provides a vital understanding of the hernia's location and size, involved viscera, and severity of associated complications. Reader familiarity with the imaging appearances and anatomic landmarks of hernias is important for correct diagnosis, which may impact preoperative planning and reduce morbidity. This article reviews the appearance of anatomic structures in the abdominal wall and pelvis that are important for diagnosing common and uncommon abdominal and pelvic hernias, and it highlights key imaging features that are helpful for differentiating hernias, mimics, and their complications. Online DICOM image stacks are available for this article . ©RSNA, 2017.


Subject(s)
Hernia/diagnostic imaging , Anatomic Landmarks , Diagnosis, Differential , Humans , Magnetic Resonance Imaging , Tomography, X-Ray Computed , Ultrasonography
11.
Br J Cancer ; 109(7): 1974-80, 2013 Oct 01.
Article in English | MEDLINE | ID: mdl-24022194

ABSTRACT

BACKGROUND: We conducted a population-based study to evaluate whether non-small cell lung cancer (NSCLC) prognosis was worse in HIV-infected compared with HIV-uninfected patients. METHODS: Using the Surveillance, Epidemiology and End Results (SEER) registry linked to Medicare claims, we identified 267 HIV-infected patients and 1428 similar controls with no evidence of HIV diagnosed with NSCLC between 1996 and 2007. We used conditional probability function (CPF) analyses to compare survival by HIV status accounting for an increased risk of non-lung cancer death (competing risks) in HIV-infected patients. We used multivariable CPF regression to evaluate lung cancer prognosis by HIV status adjusted for confounders. RESULTS: Stage at presentation and use of stage-appropriate lung cancer treatment did not differ by HIV status. Median survival was 6 months (95% confidence interval (CI): 5-8 months) among HIV-infected NSCLC patients compared with 20 months (95% CI: 17-23 months) in patients without evidence of HIV. Multivariable CPF regression showed that HIV was associated with a greater risk of lung cancer-specific death after controlling for confounders and competing risks. CONCLUSION: NSCLC patients with HIV have a poorer prognosis than patients without evidence of HIV. NSCLC may exhibit more aggressive behaviour in the setting of HIV.


Subject(s)
Carcinoma, Non-Small-Cell Lung/complications , Carcinoma, Non-Small-Cell Lung/mortality , HIV Infections/complications , HIV Infections/mortality , Lung Neoplasms/complications , Lung Neoplasms/mortality , Aged , Carcinoma, Non-Small-Cell Lung/diagnosis , Carcinoma, Non-Small-Cell Lung/pathology , Female , HIV Infections/diagnosis , Humans , Lung/pathology , Lung Neoplasms/diagnosis , Lung Neoplasms/pathology , Male , Middle Aged , Prognosis , SEER Program , Survival Rate , United States
12.
Article in English | MEDLINE | ID: mdl-23365910

ABSTRACT

The aim of this study was to evaluate the effect of contrast agent gadobutrol on the magnetic resonance diffusion-weighted imaging (MR DWI). Gadobutrol has higher relaxivity than Gd-DTPA and it also has higher formulation 1.0 M than Gd-DTPA 0.5 M. VX2 tumor implanted on the left thigh of each New Zealand rabbit was used as the animal model. The MR scanning was performed using a 1.5 T clinical whole-body MR scanner with an 8-channel knee coil. The results showed that there were significant differences in the signal-to-noise ratio (SNR) and apparent diffusion coefficient (ADC) values between tumor and muscle both before and after gadobutrol injection (0.1 mmol/kg). However, there were no significant differences in the SNR and ADC values of tumor or muscle before and after gadobutol administration. There were also no significant difference in the contrast-to-noise ratio (CNR) values of tumor and muscle before and after gadobutrol injection.


Subject(s)
Contrast Media/pharmacology , Diffusion Magnetic Resonance Imaging/methods , Neoplasms/diagnostic imaging , Organometallic Compounds/pharmacology , Signal-To-Noise Ratio , Animals , Muscle, Skeletal/diagnostic imaging , Rabbits , Radiography
13.
IEEE Trans Biomed Eng ; 58(9): 2607-16, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21690002

ABSTRACT

Modality-independent elastography (MIE) is a method of elastography that reconstructs the elastic properties of tissue using images acquired under different loading conditions and a biomechanical model. Boundary conditions are a critical input to the algorithm and are often determined by time-consuming point correspondence methods requiring manual user input. This study presents a novel method of automatically generating boundary conditions by nonrigidly registering two image sets with a demons diffusion-based registration algorithm. The use of this method was successfully performed in silico using magnetic resonance and X-ray-computed tomography image data with known boundary conditions. These preliminary results produced boundary conditions with an accuracy of up to 80% compared to the known conditions. Demons-based boundary conditions were utilized within a 3-D MIE reconstruction to determine an elasticity contrast ratio between tumor and normal tissue. Two phantom experiments were then conducted to further test the accuracy of the demons boundary conditions and the MIE reconstruction arising from the use of these conditions. Preliminary results show a reasonable characterization of the material properties on this first attempt and a significant improvement in the automation level and viability of the method.


Subject(s)
Algorithms , Elasticity Imaging Techniques/methods , Image Processing, Computer-Assisted/methods , Breast/anatomy & histology , Computer Simulation , Female , Finite Element Analysis , Humans , Magnetic Resonance Imaging , Phantoms, Imaging , Tomography, X-Ray Computed
14.
Am J Transplant ; 10(7): 1713-6, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20642694

ABSTRACT

We describe a case of nevirapine-induced Stevens-Johnson Syndrome (SJS) and fulminant hepatic failure (FHF) requiring liver transplantation. Five weeks prior to admission, a 57-year-old female with HIV infection had been switched to a nevirapine-based regimen of highly active antiretroviral therapy (HAART) with a CD4 cell count of 695/mm(3). Examination of the explanted native liver at initial transplantation revealed massive hepatic necrosis consistent with drug-induced liver injury. Primary graft nonfunction complicated the early postoperative course and liver retransplantation was required. On follow-up 2 years later, she remains in good health with an undetectable viral load on an efavirenz-based regimen of HAART. To our knowledge, this is the first report of successful liver transplantation following SJS and FHF.


Subject(s)
Anti-HIV Agents/adverse effects , Liver Failure, Acute/chemically induced , Liver Transplantation , Nevirapine/adverse effects , Stevens-Johnson Syndrome/chemically induced , Anti-HIV Agents/therapeutic use , Antiretroviral Therapy, Highly Active/adverse effects , Antiretroviral Therapy, Highly Active/methods , Female , HIV Infections/drug therapy , Hemofiltration , Humans , Liver Failure, Acute/surgery , Middle Aged , Nevirapine/therapeutic use , Stevens-Johnson Syndrome/surgery , Treatment Outcome
15.
Biomed Eng Online ; 9: 8, 2010 Feb 12.
Article in English | MEDLINE | ID: mdl-20149261

ABSTRACT

A semi-automated, non-rigid breast surface registration method is presented that involves solving the Laplace or diffusion equations over undeformed and deformed breast surfaces. The resulting potential energy fields and isocontours are used to establish surface correspondence. This novel surface-based method, which does not require intensity images, anatomical landmarks, or fiducials, is compared to a gold standard of thin-plate spline (TPS) interpolation. Realistic finite element simulations of breast compression and further testing against a tissue-mimicking phantom demonstrate that this method is capable of registering surfaces experiencing 6 - 36 mm compression to within a mean error of 0.5 - 5.7 mm.


Subject(s)
Algorithms , Breast/anatomy & histology , Elasticity Imaging Techniques/methods , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Pattern Recognition, Automated/methods , Subtraction Technique , Computer Simulation , Female , Humans , Image Enhancement/methods , Models, Biological , Reproducibility of Results , Sensitivity and Specificity
16.
Med Phys ; 32(5): 1308-20, 2005 May.
Article in English | MEDLINE | ID: mdl-15984683

ABSTRACT

The use of palpation information for skin disease characterization is not as commonly used as in other soft tissues, although mechanical differences within lesions have been noted. For example, regions of hyperkeratosis have the potential to transform into cancerous lesions and likely feature different material properties from those of surrounding normal tissue due to varying cytoarchitecture. As a result, the spatial distribution of lesion mechanical properties may serve to assist a diagnosis or enhance visualization of the complete extent of a cancerous region, i.e., accurate information regarding the margins of disease for surgical therapy. In this work, a multiresolution extension to a novel elastographic imaging method called Modality Independent Elastography (MIE) is used to characterize the mechanical properties of a skin-like phantom embedded with a mock stiff lesion. Simulation studies were also performed to investigate the potential for characterizing realistic melanoma lesions. Elasticity image reconstructions from the phantom experiments localized the stiff inclusion and had good correlation between the Young's modulus contrast ratio and experimental measurements from material testing. In addition, multiresolution MIE was shown to be a more robust framework than its single-resolution version. Results from the melanoma simulation demonstrate the potential for using multiresolution MIE with dermoscopic images.


Subject(s)
Algorithms , Dermoscopy/methods , Image Interpretation, Computer-Assisted/methods , Melanoma/pathology , Melanoma/physiopathology , Physical Stimulation/methods , Skin Neoplasms/pathology , Skin Neoplasms/physiopathology , Dermoscopy/instrumentation , Elasticity , Humans , Phantoms, Imaging , Reproducibility of Results , Sensitivity and Specificity , Stress, Mechanical
17.
Conf Proc IEEE Eng Med Biol Soc ; 2005: 1385-7, 2005.
Article in English | MEDLINE | ID: mdl-17282456

ABSTRACT

Recently, the use of MRI contrast agents has been proven to be substantially improved sensitivity and specificity in many clinical applications. CE-MRA has higher blood signal based on the T1 and T2-shortening property of contrast agents, so that even the small vessels can be visualized. The use of contrast agents can improve lesion detection and characterization. The routinely used dose of contrast agents in the routine MRI examinations only relies on the weight of the subject. The purpose of this study is to obtain the clinically optimal dose for 3D-TOF (time-of-flight) pulse sequences for CE-MRA examinations. In the phantom study, ten test tubes were filled with saline mixed with different dose of Gd-DTPA. It is found that the optimal dose of Gd-DTPA for saline phantom by using 3D-TOF pulse sequences is 20 mM. Also, there has no differences of optimal doses between Omniscan and Magnivist contrast agents Gd-DTPA. The results show that consistent high quality CE-MRA images might be obtained by using 0.25M Gd-DTPA (half of the routine dose) with 3~4 cc/sec injection rate for all clinical cases. The benefits of this study might be to minimize dose and potential toxicity. Additionally, the decrease of the cost of contrast agents might be achieved. It is expected to provide the recommended dose of Gd-DTPA for contrast enhanced MRA in clinical routine diagnosis.

19.
Magn Reson Med ; 32(6): 714-24, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7869893

ABSTRACT

We propose a compartmental model to explain the signal enhancement curves following the bolus injection of Gd-DTPA. The model incorporates vascular volume fraction contribution, and the possibility of having different transport constants between the plasma and extravascular components. A Walker 256 carcinoma grown in rat muscle was used to demonstrate the capability of this model. Several different types of tissues were included in the measurements: normal, quickly enhanced, slowly enhanced, and necrotic tissues. Blood volume and blood-tissue permeability information can be derived from the dynamic contrast-enhanced MRI study employing the proposed model. In the tissue contrast enhancement curve, the initial rising slope after injection is related to the blood volume (or, vascular volume fraction), the maximum enhancement ratio is related to the uptake of tissue, and the decay rate is related to the clearance of tracer from tissue. The measured permeability constant is not the conventional permeability; instead they are contrast agents uptake and clearance rates, which are limited by the blood perfusion. These parameters can be used to characterize different enhancement patterns.


Subject(s)
Carcinoma 256, Walker/diagnosis , Contrast Media , Magnetic Resonance Imaging/methods , Muscular Diseases/diagnosis , Organometallic Compounds , Pentetic Acid/analogs & derivatives , Soft Tissue Neoplasms/diagnosis , Albumins , Animals , Calibration , Female , Gadolinium DTPA , Image Enhancement/methods , Models, Structural , Rats , Rats, Sprague-Dawley , Signal Processing, Computer-Assisted
20.
Br J Haematol ; 45(1): 143-51, 1980 May.
Article in English | MEDLINE | ID: mdl-6769466

ABSTRACT

The relationships between factor VIII associated activities, platelet function, and venous thrombosis were studied in 18 patients with lower limb paralysis following acute spinal cord injury (SCI). Deep vein thrombosis (DVT) was detected in 13 patients (72%). Eight of the 13 thromboses were documented between 6 and 8 d following injury while the other five episodes were noted on days 11 (two), 13, 18 and 22. The detection of thrombosis was preceded by marked increases in VIIIR:Ag and VIII:RCoF whereas VIII:C was only marginally increased. The platelet aggregation response to collagen was hyperactive by the sixth day while the platelet aggregate ratio (PAR) did not become abnormal until after DVT was detected. These studies suggest a chronology in the series of events leading to DVT in patients with lower limb paralysis following SCI. Initial elevations in VIII:Ag and VIII:RCoF are followed in sequence by increased platelet responsiveness to collagen, the occurrence of DVT, and the appearance of circulating platelet aggregates. Conceivably, VIIIR:Ag elaborated by endothelial cells alters platelet reactivity and provides an important determinant for venous thrombosis.


Subject(s)
Factor VIII/metabolism , Platelet Count , Spinal Cord Injuries/blood , Thrombophlebitis/blood , Adolescent , Adult , Aged , Female , Fibrinogen/metabolism , Humans , Male , Middle Aged , Platelet Aggregation , Spinal Cord Injuries/complications , Time Factors , von Willebrand Factor/analysis
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