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Biomedical subjects

Bonnie N Joe

Publications and source records attributed to Bonnie N Joe.

17 recordsLinked to original sources
PubMed2007

Predicting biliary complications in right lobe liver transplant recipients according to distance between donor's bile duct and corresponding hepatic artery.

PURPOSE: To retrospectively determine whether biliary complications in recipients of living-donor right lobe liver grafts can be predicted at pretransplantation donor computed tomography (CT). MATERIALS AND METHODS: The human research committee approved this study. The requirement for informed consent was waived. Multi-detector row CT cholangiography and CT angiography were performed in 44 consecutive right lobe liver donors (25 men, 19 women; mean age, 37 years). When CT cholangiography in the donor demonstrated the right biliary anatomy (conventional or variant), the shortest distance between the right main (or second-order) hepatic artery and the corresponding right main (or second-order) bile duct was measured and compared with posttransplantation biliary complications in the transplant recipient by using generalized estimating equations. RESULTS: In 22 transplant recipients with one right main duct-to-common duct anastomosis (ie, conventional donor anatomy), the distance between the donor's right main bile duct and hepatic artery generally was small (mean distance, 3.8 mm; range, 1-14 mm) and unrelated (P=.46) to biliary complications (n=6). In 22 recipients who required two second-order right duct anastomoses (ie, with variant donor anatomy), the distance between the donor's second-order duct and corresponding hepatic artery was more variable (mean distance, 6.6 mm; range, 1-32.5 mm), and biliary complications were significantly more common when this distance was 10 mm or greater (in eight of 13 ducts with conventional anatomy and four of 31 ducts with variant anatomy, P<.05). CONCLUSION: Right lobe liver graft recipients who have variant right biliary anatomy and a second-order bile duct 10 mm or farther from the corresponding hepatic artery are at high risk for biliary complications, possibly because of a predisposition to ischemic injury.

Adult↗
PubMed2006

Feasibility of magnetic resonance spectroscopy for evaluating fetal lung maturity.

BACKGROUND/PURPOSE: Amniocentesis is an invasive procedure with inherent risks. Magnetic resonance (MR) spectroscopy is a safe noninvasive way of measuring levels of choline-containing compounds (including surfactant) and other metabolites. The purpose of this study was to test the feasibility of assessing fetal lung maturity in vivo and ex vivo using MR spectroscopy to determine differences in amniotic fluid choline concentrations between the second and third trimesters. METHODS: Magnetic resonance spectroscopy was performed on ex vivo samples of amniotic fluid from second- and third-trimester fetuses. In vivo MR spectroscopy was performed on amniotic fluid and fetal lungs in third-trimester fetuses. Spectral acquisition and analysis were performed by an attending radiologist in conjunction with an MR spectroscopist. RESULTS: Choline-containing compounds were observed from 3.20 to 3.25 ppm. Comparison of spectra from second- and third-trimester amniocentesis revealed a trend toward increased choline at later gestational ages. Spectra from amniotic fluid and lungs of a third-trimester fetus showed that choline can be detected in the in vivo setting. CONCLUSIONS: Magnetic resonance spectroscopy is a safe noninvasive procedure that enables measurement of choline-containing compounds in fetal lung and amniotic fluid. Magnetic resonance spectroscopy shows a trend toward an increased quantity of choline in third- vs second-trimester amniocentesis.

Amniotic Fluid↗
PubMed2006

Gallstone detection at CT in vitro: effect of peak voltage setting.

This study was a retrospective single-institutional study approved by the Committee on Human Research and was HIPAA compliant. A waiver for informed consent was granted. The purpose of the study was to evaluate the effect of four peak voltage settings on the in vitro conspicuity of gallstones in an anthropomorphic phantom at computed tomography (CT). An anthropomorphic phantom was scanned with (n = 86) or without (n = 85) gallstones at CT by using 80, 100, 120, and 140 kVp. The sensitivity for gallstone detection was significantly higher at 140 kVp (86% [74 of 86] for reader 1 and 81% [70 of 86] for reader 2) than at lower voltage settings (up to 67% [58 of 86] for reader 1 and 63% [54 of 86] for reader 2, P < .05 for each reader), regardless of gallstone size (<1.0 cm vs > or =1.0 cm in diameter, P < .05 for each reader). CT attenuation measurements were not useful for determination of gallstone composition. Abdominal CT performed at 140 kVp may be useful when gallstone disease is of clinical concern.

Adult↗
PubMed2006

CT and MRI of adnexal masses in patients with primary nonovarian malignancy.

OBJECTIVE: The purpose of this pictorial essay is to review the differential considerations when an adnexal mass is detected on CT or MRI in a patient with a primary nonovarian malignancy. CONCLUSION: Such adnexal masses may be metastases to the ovaries, primary ovarian malignancy, or incidental benign disorders. Solid masses are more likely metastases, but metastases can be predominantly cystic and primary ovarian cancers can be solid. MRI may help characterize incidental benign entities such as endometriosis, fibroma, and peritoneal inclusion cysts.

Adnexal Diseases↗
PubMed2005

Evaluation of 1H-magnetic resonance spectroscopy of breast cancer pre- and postgadolinium administration.

OBJECTIVES: We sought to evaluate spectroscopic measurements in breast cancer and compare variability in choline peak parameters related to contrast administration versus that inherent to repeated measurements. MATERIALS AND METHODS: Single-voxel, proton spectroscopy measurements were obtained before and after the administration of gadolinium on 15 patients with > or = 1-cm breast cancers. The protocol was repeated on a separate day in 7 patients. RESULTS: Postcontrast spectra demonstrated a significant increase in choline peak linewidth (day 1: 15% +/- 21%, P = 0.03; day 2: 19% +/- 12%, P = 0.001) and decrease in choline peak area (day 1: 11% +/- 9% (P < 0.001); day 2: 18% +/- 21% (P = 0.03). A variance-components analysis indicated that day-to-day variation in linewidth accounted for 0.0% of the total variation in width measurements and was not significant (P = 0.85). Day-to-day variation in area was also not significant (0.0%, P = 0.95). CONCLUSIONS: Contrast administration caused significant increases in choline peak linewidth and decreases in choline peak area in spectroscopic measurements of breast cancer.

Breast Neoplasms↗
PubMed2005

Inferior vena cava filling defects on CT and MRI.

OBJECTIVE: The purpose of this article is to describe the appearance and causes of inferior vena cava (IVC) filling defects, how such findings may be accurately characterized, and the clinical significance of IVC filling defects. Filling defects in the IVC observed at MDCT and MRI may be a result of flow artifacts, anatomic variants, or bland or malignant thrombus. CONCLUSION: Familiarity with anatomy and flow effects is critical for distinguishing true from false filling defects in the IVC. Delayed imaging after administration of IV contrast material and dedicated MRI sequences may be helpful for further characterization of such findings. Once a true filling defect of the IVC is established, identification of the cause, whether benign or malignant, and extent will guide clinical treatment.

Artifacts↗
PubMed2004

Fetal relative lung volume: quantification by using prenatal MR imaging lung volumetry.

PURPOSE: To retrospectively determine a biometric algorithm for calculating relative lung volume in fetuses with normal lungs and of a wide range of gestational ages by using proved independent variables and to retrospectively investigate the use of this algorithm in fetuses with pulmonary hypoplasia. MATERIALS AND METHODS: Total lung volume (TLV) was measured by using planimetry on single-shot rapid acquisition with relaxation enhancement magnetic resonance (MR) images obtained in 91 fetuses with ultrasonographically (US) normal chests and 28 fetuses with US-determined pulmonary hypoplasia. All fetuses were aged between 18 and 38 weeks gestation. Analysis of covariance was used to identify parameters that were not different between the fetuses with US-determined normal and those with US-determined abnormal chests, and these variables were used to construct an algorithm for calculating predicted lung volume. The relative lung volume-that is, the observed lung volume expressed as a percentage of the predicted lung volume-was then calculated in fetuses with pulmonary hypoplasia. RESULTS: There was no significant difference in mean maternal or gestational age between the two fetus groups. Stepwise regression analysis was used to generate the following equation for predicting fetal lung volume on the basis of independent biometric indexes, with a correlation coefficient of 0.93: TLV = (0.52 . LV) + (0.33 . BD) - (0.06 . FL) - 13.7, with TLV and liver volume (LV) in milliliters and biparietal diameter (BD) and femoral length (FL) in centimeters. In the fetuses with normal chests, relative lung volume varied between 51% and 134%. In the fetuses with pulmonary hypoplasia, relative lung volume varied between 6% and 70%. CONCLUSION: The predicted lung volume in fetuses of a wide range of gestational ages can be calculated with a high degree of accuracy, enabling prenatal MR imaging lung volumetry in which relative lung volume is used to quantify fetal pulmonary hypoplasia.

Adolescent↗
PubMed2004

Model for predicting the impact of gadolinium on plasma calcium measured by the o-cresolphthalein method.

BACKGROUND: Gadolinium formulations, which are administered as contrast agents in magnetic resonance imaging examinations, interfere with colorimetric serum calcium determinations. METHODS: We performed an in vitro study to determine the extent to which three gadolinium formulations-gadodiamide (Omniscan), gadopentetate dimeglumine (Magnevist), and gadoversetamide (OptiMARK)-affect measurements by two methods that use o-cresolphthalein (Dade Behring, Inc. and Roche Diagnostics) and one that uses arsenazo dye (Equal Diagnostics). We also compared values from the o-cresolphthalein methods for 116 samples from patients administered gadodiamide. RESULTS: Magnevist did not affect any of the methods evaluated, whereas Omniscan and OptiMARK were identical in their effects. For the Dade method, the differences from the control sample were < or =4.0 and 7.0 mg/L at 0.25 and 0.5 mmol/L gadolinium, respectively. For the Roche method, the differences were 19, 9.0, and 5.0 mg/L at 0.5, 0.25, and 0.125 mmol/L gadolinium, respectively. Falsely increased calcium values were seen when samples were measured by the arsenazo-based method: differences were 6.0 and 3.0 mg/L at 1.0 and 0.5 mmol/L gadolinium. Using patient data collected at our institution, we were able to generate a model for predicting, from a patient's glomerular filtration rate and the time elapsed since administration, the impact of Omniscan on calcium measurements by the o-cresolphthalein method from Roche Diagnostics. CONCLUSIONS: The predictive model can be used to calculate, in patients who have received gadodiamide, the minimum length of time to wait before blood collection to avoid pseudohypocalcemia when the Roche o-cresolphthalein method is used.

Calcium↗
PubMed2003

Improving mass measurement of coronary artery calcification using threshold correction and thin collimation in multi-detector row computed tomography: in vitro experiment.

RATIONALE AND OBJECTIVES: This in vitro study was designed to improve the accuracy of coronary calcium mass measurement from computed tomography (CT) images by developing threshold-based calcium CT number correction and thin-slice spiral techniques. MATERIALS AND METHODS: A cardiac CT phantom containing simulated calcified cylinders of known calcium density was scanned with sequential 4 x 2.5-, spiral 16 x 1.5-, and spiral 16 x 0.75-mm collimation on 4- and 16-detector row CT scanners. The images obtained from the spiral scans were reconstructed in various slice widths. The calcified cylinders were imaged and their mean CT number and size were measured at thresholds ranging from 50 to 390 Hounsfield unit. The calcium mass measured was compared with the actual value to determine errors, and threshold-based correction factors were derived to minimize the errors. RESULTS: The minimum amount of measurable calcium in 1-mm cylinder was 0.3 mg at the 16 X 1.5-mm protocol and 0.2 mg at the 16 x 0.75-mm protocol. Compared with 2.5-mm sequential protocol, thin-slice spiral protocols yielded a higher radiation exposure and lower or similar image noise levels. The error in calcium mass after correction was significantly smaller than that in measured mass (P < .0001) and was consistent between the imaging protocols (P = .49). The accuracy of mass measurements was clearly improved by using thin-slice imaging protocols especially in 200-mg/cm3 calcium density (P < .0001). CONCLUSION: The accuracy of calcium mass CT measurement can be improved by threshold-based calcium CT number correction and thin collimation spiral techniques.

Calcinosis↗
PubMed2003

Adrenal masses: CT characterization with histogram analysis method.

PURPOSE: To evaluate a histogram analysis method for differentiating adrenal adenoma from metastasis at computed tomography (CT). MATERIALS AND METHODS: In a retrospective review of 2 years of clinical CT records, 223 adrenal adenomas in 193 patients (115 with contrast material-enhanced CT, 43 with unenhanced and enhanced CT, and 35 with unenhanced CT) and 31 metastases (25 patients with enhanced CT) were found. In 158 patients with adenomas at enhanced CT, diagnosis was based on stable mass size for more than 1 year (n = 135) and characteristic signal intensity decrease at chemical shift magnetic resonance imaging (n = 23). In 35 patients with adenomas at unenhanced CT, mean attenuation was 10 HU or less. Diagnosis of all metastases was based on rapid growth of a mass or new mass in less than 6 months in patients with cancer. Adrenal metastases with extensive necrosis were excluded. Histogram analysis was performed in a circular region of interest (ROI) for mean attenuation, number of pixels, and range of pixel attenuation for all pixels and for the subset of pixels with less than 0 HU ("negative" pixels). Correlation between mean attenuation and percentage negative pixels was calculated. RESULTS: Negative pixels were present in all 74 unenhanced adenomas with mean attenuation of 10 HU or less and in 14 of 16 unenhanced adenomas with mean attenuation above 10 HU. Of 184 enhanced adenomas, only 20 had mean attenuation of 10 HU or less, but 97 contained negative pixels (77 of these 97 masses had mean attenuation above 10 HU). Increase in percentage negative pixels was highly correlated with decrease in mean attenuation of both unenhanced and enhanced adenomas. None of the adrenal metastases had mean attenuation of 10 HU or less or contained negative pixels. CONCLUSION: The histogram method is far more sensitive than the 10-HU threshold method for diagnosis of adrenal adenomas at enhanced CT, with specificity maintained at 100%.

Adenoma↗
PubMedDate not supplied

Computed tomography and magnetic resonance imaging of inferior vena caval thrombus associated with metastasis to the kidney.

The computed tomography and magnetic resonance imaging findings in 2 cases of inferior vena caval thrombus associated with metastases to the kidney are presented. In both cases, the radiologic findings were suggestive of renal cell carcinoma. Recognition that metastases to the kidney can be associated with inferior vena caval thrombus broadens the differential diagnosis in a patient with a renal mass, an inferior vena caval filling defect, and a known primary malignancy, potentially altering the diagnostic approach.

Adenocarcinoma↗
PubMedDate not supplied

Atypical cases of gallstone ileus evaluated with multidetector computed tomography.

OBJECTIVE: To describe the multidetector computed tomography (CT) findings in 3 patients with atypical gallstone ileus. METHODS: We retrospectively evaluated computed radiography and CT images from three cases of surgically proven gallstone ileus. Two radiologists evaluated by consensus all images for the presence of ectopic gallstone, small bowel obstruction, intrahepatic pneumobilia, cholecystic pneumobilia. One author recorded whether diagnosis of gallstone ileus was made prospectively on radiologic reports and correlated findings to pathology. RESULTS: All cases of gallstone ileus were atypical in that one patient had porcelain gallbladder, one had recurrent pyogenic cholangitis, and one was only 35 years of age. Prospective clinical diagnosis of gallstone ileus was made in only 1 patient at computed radiography and all 3 patients at CT. Retrospectively, small bowel obstruction and cholecystic pneumobilia were identified retrospectively in all 3 patients at both computed radiography and MDCT, and an ectopic gallstone, intrahepatic pneumobilia, and choledochoduodenal fistula was seen in 2, 1, and 0 patients at computed radiography and 3, 2, and 3 patients at CT respectively. CONCLUSION: Multidetector CT is an accurate means to diagnose gallstone ileus, even in patients with atypical features. In particular, multidetector CT is useful for identifying the ectopic gallstone at the transition point between dilated and decompressed bowel.

Adult↗
PubMedDate not supplied

Magnetic resonance imaging of ovarian cancer arising in endometriomas.

The magnetic resonance imaging (MRI) findings in 2 cases of ovarian cancer arising in an endometrioma are presented. In both cases, the cancer was evident as an enhancing mass within a blood-filled adnexal cyst. The MRI findings of an enhancing mass within a blood-filled adnexal cyst should prompt consideration of ovarian cancer arising in an endometrioma, facilitating recognition of a superimposed malignancy and potentially allowing for earlier and more efficacious treatment.

Adenocarcinoma, Clear Cell↗
PubMedDate not supplied

Magnetic resonance imaging of hepatocellular carcinoma mimicking focal nodular hyperplasia: a potential pitfall in patients with cirrhosis?

The magnetic resonance imaging findings in 2 cases of pathologically proven hepatocellular carcinoma that mimicked focal nodular hyperplasia are presented. Both cases were found in patients with cirrhosis, a condition in which focal nodular hyperplasia is unlikely to occur. Recognition that hepatocellular carcinoma may mimic focal nodular hyperplasia in patients with cirrhosis may prevent misdiagnosis and allow for earlier intervention.

Aged↗