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PubMed2003

Normal spinal bone marrow in adults: dynamic gadolinium-enhanced MR imaging.

PURPOSE: To determine the patterns of dynamic enhancement of normal spinal bone marrow in adults at gadolinium-enhanced magnetic resonance (MR) imaging and the changes that occur with aging. MATERIALS AND METHODS: Dynamic contrast material-enhanced MR imaging of the thoracolumbar spine was performed in 71 patients. The maximum percentage of enhancement (Emax), enhancement slope, and enhancement washout were determined from bone marrow enhancement time curves (ETCs). The bone marrow signal intensity on T1-weighted spin-echo MR images was qualitatively classified into three grade categories. Quantitative ETC values were correlated with patient age and bone marrow fat content grade. Statistical analysis included mean t test comparison, analysis of variance, and regression analysis of the correlations between age and quantitative MR parameters. RESULTS: Emax, slope, and washout varied widely among the patients. Emax values were obtained within 1 minute after contrast material injection and ranged from 0% to 430%. Emax values were significantly higher in patients younger than 40 years than in those aged 40 years or older (P <.001). These values decreased with increasing age in a logarithmic relationship (r = 0.71). Emax values decreased as fat content increased, but some overlap among the fat content grades was noted. Analysis of variance revealed that Emax was significantly related to age (younger than 40 years vs 40 years or older) (P <.001) and fat content grade (P <.001) but not significantly related to sex. CONCLUSION: Dynamic contrast-enhanced MR imaging patterns of normal spinal bone marrow are dependent mainly on patient age and fat content.

Adolescent↗

PubMed2004

Solitary pulmonary nodules: dynamic enhanced multi-detector row CT study and comparison with vascular endothelial growth factor and microvessel density.

PURPOSE: To evaluate enhancement dynamics of solitary pulmonary nodules at multi-detector row computed tomography (CT) and to correlate results with extent of tumor angiogenesis in pathologic specimens. MATERIALS AND METHODS: One hundred thirty-one patients with solitary pulmonary nodules underwent unenhanced thin-section CT, followed by dynamic helical CT (throughout the nodule for 30 mm along the z-axis [13 images] and at 20-second intervals for 3 minutes [130 images total]) after intravenous injection of 120 mL of contrast medium. Diagnosis of malignancy or benignancy was assigned in 109 patients, and follow-up imaging suggested benignancy in the remaining 22. CT findings were analyzed for peak attenuation, net enhancement, and enhancement dynamics. In 54 patients with surgical diagnoses, Pearson correlation coefficient was used to correlate enhancement pattern with extent of microvessel density and vascular endothelial growth factor (VEGF) staining. RESULTS: With 30 HU or more of net enhancement as a cutoff value in differentiation of malignant and benign nodules, sensitivity for malignant nodules was 99% (69 of 70 malignant nodules), specificity was 54% (33 of 61 benign nodules), positive predictive value was 71% (69 of 97 malignant readings), negative predictive value was 97% (33 of 34 benign readings), and accuracy was 78% (102 of 131 nodules). Peak attenuation was correlated positively with extent of microvessel density (r = 0.369, P =.006) and VEGF staining (r = 0.277, P =.042). Malignant nodules showed significantly higher VEGF expression (P =.009) than that of benign nodules. CONCLUSION: Dynamic enhancement with multi-detector row CT shows high sensitivity and negative predictive values for diagnosis of malignant nodules but low specificity because of highly enhancing benign nodules. Extent of enhancement reflects underlying nodule angiogenesis.

Adult↗

PubMed2004

Defining intrahepatic biliary anatomy in living liver transplant donor candidates at mangafodipir trisodium-enhanced MR cholangiography versus conventional T2-weighted MR cholangiography.

PURPOSE: To compare three-dimensional (3D) mangafodipir trisodium-enhanced T1-weighted magnetic resonance (MR) cholangiography with conventional T2-weighted MR cholangiography for depiction and definition of intrahepatic biliary anatomy in liver transplant donor candidates. MATERIALS AND METHODS: One hundred eight healthy liver transplant donor candidates were examined with two MR cholangiographic methods. All candidates gave written informed consent, and the study was approved by the institutional review board. First, breath-hold transverse and coronal half-Fourier single-shot turbo spin-echo and breath-hold oblique coronal heavily T2-weighted turbo spin-echo sequences were performed. Second, mangafodipir trisodium-enhanced breath-hold fat-suppressed 3D gradient-echo sequences were performed through the ducts (oblique coronal plane) and through the entire liver (transverse plane). Interpretation of biliary anatomy findings, particularly variants affecting right liver lobe biliary drainage, and degree of interpretation confidence at both 3D mangafodipir trisodium-enhanced MR cholangiography and T2-weighted MR cholangiography were recorded and compared by using the Wilcoxon signed rank test. Then, consensus interpretations of both MR image sets together were performed. Intraoperative cholangiography was the reference-standard examination for 51 subjects who underwent right lobe hepatectomy. The McNemar test was used to compare the accuracies of the individual MR techniques with that of the consensus interpretation of both image sets together and to compare each technique with intraoperative cholangiography. RESULTS: Biliary anatomy was visualized with mangafodipir trisodium enhancement in all patients. Mangafodipir trisodium-enhanced image findings agreed with findings seen at combined interpretations significantly more often than did T2-weighted image findings (in 107 [99%] vs 88 [82%] of 108 donor candidates, P < .001). Confidence was significantly higher with the mangafodipir trisodium-enhanced images than with the T2-weighted images (mean confidence score, 4.5 vs 3.4; P < .001). In the 51 candidates who underwent intraoperative cholangiography, mangafodipir trisodium-enhanced imaging correctly depicted the biliary anatomy more often than did T2-weighted imaging (in 47 [92%] vs 43 [84%] donor candidates, P = .14), whereas the two MR imaging techniques combined correctly depicted the anatomy in 48 (94%) candidates. CONCLUSION: Mangafodipir trisodium-enhanced 3D MR cholangiography depicts intrahepatic biliary anatomy, especially right duct variants, more accurately than does conventional T2-weighted MR cholangiography.

Adolescent↗

PubMed2006

Contrast-enhanced MR imaging of the breast at 3.0 and 1.5 T in the same patients: initial experience.

PURPOSE: To establish a pulse sequence for dynamic contrast material-enhanced magnetic resonance (MR) imaging of the breast at 3.0 T and to prospectively compare MR imaging at 3.0 T with MR imaging at 1.5 T in the same patients. MATERIALS AND METHODS: A prospective intraindividual internal review board-approved study was performed in 37 women with 53 lesions (25 breast cancers, 28 benign focal lesions) who underwent contrast-enhanced dynamic bilateral subtraction MR imaging twice, once at 1.5 T with a standard technique (voxel size, 1.44 mm3) and once at 3.0 T (voxel size, 0.45-0.72 mm3) with variable repetition time and flip angle settings. Written informed consent was obtained. Sagittal single breast high-spatial-resolution MR imaging was performed with active fat suppression. Image quality, number and features of enhancing lesions, and Breast Imaging Reporting and Data System categories were compared by using the Wilcoxon matched-pairs signed rank test and Student t test for matched pairs. Diagnostic confidence was compared by using a receiver operating characteristic (ROC) analysis. RESULTS: With repetition time prolonged to account for longer T1 relaxation times at 3.0 T and a flip angle of 60 degrees, enhancement rates at 3.0 T were substantially below those at 1.5 T. In two patients with benign lesions, enhancement was rated as insufficient to establish diagnosis. When parameter settings were kept equivalent, equivalent enhancement rates were observed with both systems. With these settings, 3.0-T MR imaging yielded homogeneous signal intensity over the entire field of view. No dielectric resonance effects were observed. Overall image quality scores for the dynamic series were slightly higher at 3.0 T (P<.01). A total of 49 lesions were prospectively identified with both systems. Owing to substantial patient motion at 1.5 T, two malignant lesions in one patient were visualized at 3.0 T only. At 3.0 T, differential diagnosis of enhancing lesions was possible with higher diagnostic confidence, as reflected by a larger area under the ROC curve (P<.05). CONCLUSION: Initial experiences indicate that contrast-enhanced MR imaging at 3.0 T is nearing readiness for clinical use.

Adult↗

PubMed2006

Pancreas: optimal scan delay for contrast-enhanced multi-detector row CT.

PURPOSE: To prospectively determine optimal scan delays for multiphasic contrast medium-enhanced imaging of the pancreas with multi-detector row computed tomography (CT). MATERIALS AND METHODS: This study was approved by an institutional review committee, and patients gave written informed consent. One hundred ninety-one patients underwent three-phase CT of the pancreas after receiving intravenous contrast medium with a fixed duration injection of 30 seconds. Patients were prospectively assigned among four groups with scan delays of 25, 45, and 65 seconds (group 1); 30, 50, and 70 seconds (group 2); 35, 55, and 75 seconds (group 3); and 40, 60, and 80 seconds (group 4). Mean CT numbers of abdominal aorta, spleen, pancreatic parenchyma, superior mesenteric artery and vein, splenic vein, and hepatic parenchyma were measured, and increases in contrast enhancement on enhanced images were assessed. Qualitative analysis was performed with a four-point scale. RESULTS: Abdominal aorta and superior mesenteric artery enhanced at a mean of 35 seconds from the start of injection (both P < .001). Pancreatic parenchyma enhanced most intensely at 35-45 seconds (P < .001) with a peak enhancement at the mean of 40 seconds. Liver parenchyma enhanced most intensely at 55-65 seconds with a peak at 60 seconds (P < .001). The mean time to peak enhancement was 45 seconds for the splenic vein and 55 seconds for the superior mesenteric vein. Qualitative results were in good agreement with quantitative results (both P < .001). CONCLUSION: With the injection protocol used in this study, optimal scan delays for imaging the pancreas were 30-35 seconds for the abdominal aorta and the superior mesenteric artery, 35-45 seconds for the pancreas, 45 seconds for the splenic vein, and 55 seconds or later for the liver.

Adult↗

PubMed2007

Chronic tibiofibular syndesmosis injury of ankle: evaluation with contrast-enhanced fat-suppressed 3D fast spoiled gradient-recalled acquisition in the steady state MR imaging.

PURPOSE: To retrospectively determine the accuracy of coronal contrast material-enhanced fat-suppressed three-dimensional (3D) fast spoiled gradient-recalled acquisition in the steady state (SPGR) magnetic resonance (MR) imaging, as compared with that of routine transverse MR imaging, in the assessment of distal tibiofibular syndesmosis injury, with arthroscopy as the reference standard. MATERIALS AND METHODS: The review board of the College of Medicine in Yonsei University approved this study; informed consent was waived. The study group comprised 45 patients (26 men, 19 women; mean age, 32.1 years; range, 18-58 years) with a chronic ankle injury who had undergone MR imaging and arthroscopic surgery. Three independent readers retrospectively reviewed the two sets of MR images (one set of gadolinium-enhanced 3D fast SPGR images and one set of routine T1-, T2-, and intermediate-weighted images). Scores from 1 to 5 in increasing order of the probability of injury were assigned to both sets. Arthroscopy was the reference standard. Syndesmotic recess height was measured on contrast-enhanced images. The two sets of images were compared for diagnostic performance with receiver operating characteristic (ROC) analysis. Dissection and histologic examination of six cadaveric ankles was performed to assess the syndesmotic area and ascertain the enhancing structure at MR imaging. RESULTS: At arthroscopy, syndesmotic injury was found in 24 ankles but not in 21 ankles. Areas under the ROC curve were significantly higher for the contrast-enhanced images (P<.05). The contrast-enhanced set showed higher accuracy, sensitivity, and specificity compared with the routine set for the assessment of syndesmosis injury. Mean syndesmotic recess height was significantly greater (P<.05) in patients with syndesmotic injury. Dissection and histologic examination revealed a highly vascular synovial fold in the syndesmotic area that is expected to enhance at MR imaging. CONCLUSION: In the assessment of chronic syndesmosis injury, coronal gadolinium-enhanced fat-suppressed 3D fast SPGR MR images were more sensitive, specific, and accurate than routine MR images.

Adipose Tissue↗

PubMed2000

Hepatic parenchymal enhancement during triple-phase helical CT: can it be used to predict which patients with breast cancer will develop hepatic metastases?

PURPOSE: To evaluate the efficacy of hepatic enhancement characteristics for identification of patients with breast cancer who are at risk for future hepatic metastases. MATERIALS AND METHODS: Triple-phase helical computed tomography (CT) was performed in 60 patients with known breast cancer without visible hepatic metastases. Peak hepatic attenuation and enhancement, and attenuation and enhancement at 25 and 30 seconds were obtained. Ratios of hepatic attenuation or enhancement at 25 and 30 seconds to peak hepatic attenuation or enhancement were calculated. A Wilcoxon rank sum test was used to compare patients with and those without subsequent hepatic metastases. RESULTS: During a mean 18-month follow-up, 18 patients (30%) developed hepatic metastases. Decreases in peak hepatic attenuation and enhancement and increases in hepatic attenuation and enhancement ratios at 25 and 30 seconds were seen in patients who developed metastases compared with those who did not (P < .05). When corrected for chemotherapy interval, these differences were not statistically significant. Using a threshold value of 0.40 or more for the enhancement ratio at 30 seconds resulted in sensitivity of 28%, specificity of 92%, and accuracy of 55%. CONCLUSION: Patients with breast cancer who develop subsequent hepatic metastases have higher relative hepatic arterial perfusion during triple-phase CT; however, after correction for chemotherapy interval, this difference was not statistically significant. Threshold values cannot be used reliably to identify patients who will develop metastases.

Adult↗

PubMed2001

Prostate cancer: contrast-enhanced us for detection.

PURPOSE: To assess the detection of prostate cancer with contrast material-enhanced transrectal sonography. MATERIALS AND METHODS: Sixty subjects were examined with conventional gray-scale, harmonic gray-scale, and power Doppler sonography. Evaluation was repeated during intravenous infusion of contrast agent. Gray-scale imaging was performed in continuous mode and with intermittent imaging by using interscan delay times of 0.5, 1.0, 2.0, and 5.0 seconds. Sextant biopsy sites were scored prospectively as benign or malignant at baseline imaging and again during enhanced transrectal sonography. RESULTS: Prostate cancer was present in 37 biopsy sites from 20 subjects. Baseline imaging demonstrated prostate cancer in 14 sites in 11 subjects. Enhanced transrectal sonography depicted prostate cancer in 24 sites in 15 subjects. Each of the five subjects in whom prostate cancer was missed had only a single biopsy core with positive findings (Gleason score < or = 6). In three of these five subjects, prostate cancer made up less than 10% of the core. The improvement in sensitivity from 38% (14 of 37 malignant foci) at baseline to 65% (24 of 37 malignant foci) with contrast enhancement was significant (P<.004, McNemar chi(2) test). Specificity was similar at baseline (267 [83%] of 323 malignant foci) and during enhanced transrectal sonography (257 [80%] of 323 malignant foci). Clustered receiver operating characteristic analysis demonstrated significant improvement in diagnostic accuracy during enhanced transrectal sonography (P =.027). CONCLUSION: Enhanced transrectal sonography improves sensitivity for the detection of malignant foci within the prostate without substantial loss of specificity. Low-volume tumors with a Gleason score of 6 or less may not be detected with enhanced transrectal sonography.

Adult↗

PubMed2006

Octreotide exerts only acute, but no sustained, effects on MRI enhancement of liver metastases in carcinoid syndrome.

We have investigated the acute and sustained hemodynamic effects of octreotide on hepatic metastases of midgut carcinoids using contrast-enhanced dynamic magnetic resonance imaging (MRI). Seven patients with the carcinoid syndrome and metastasized midgut carcinoid tumors underwent functional dynamic multi-phase gadolinium-enhanced MRI of selected liver metastases at baseline and 60 min after the subcutaneous (s.c.) administration of 100 microg octreotide, and also after 3 months with three times daily (t.i.d.) 100 microg octreotide s.c. Baseline MRIs showed the typical aspect of carcinoid liver metastases with a very bright signal on the T2-weighted sequences and intense enhancement in the arterial phase after injection of gadolinium-diethylenetriaminepentaacetate. MRIs 60 min after the s.c. administration of 100 microg octreotide showed a 34.9 +/- 6.2% (mean +/- SD) reduction in relative enhancement in the selected liver metastases as compared to baseline. In 2 patients, however, there was no (significant) reduction in the relative enhancement in the selected liver metastases 60 min after the s.c. administration of 100 microg octreotide as compared to baseline. Only in 2 patients did the MRIs at 3 months show a decrease in relative enhancement in one of the selected liver metastases. At 3 months, with 100 microg octreotide s.c. t.i.d., there was no correlation between the change in relative enhancement on MRI and the change in 24-hour 5-HIAA excretion. There is thus only an acute effect of octreotide on the perfusion of liver metastases. This study further shows that contrast-enhanced dynamic MRI can be a very useful tool for studying hemodynamic effects of medical therapies on liver metastases in patients with metastatic midgut carcinoids.

Aged↗

PubMed2026

Regulation of murine follicle-stimulating hormone β subunit transcription by newly identified enhancers.

Activin-class ligands of the transforming growth factor β family induce follicle-stimulating hormone (FSH) production by pituitary gonadotrope cells in mice via the actions of the transcription factors SMAD3, SMAD4, and FOXL2, which bind to cis-elements in the FSHβ subunit (Fshb) promoter. An enhancer region for murine Fshb transcription was identified in vitro. However, deletion of the region using CRISPR-Cas9 did not affect FSH synthesis or secretion in mice. Using single-nucleus ATAC-seq of whole murine pituitaries, we identified 3 additional open chromatin regions upstream of Fshb exclusively in gonadotropes. These regions, as well as the Fshb gene, were fully or partially closed in gonadotropes of FSH-deficient mice with genetically or pharmacologically inactivated activin type II receptors. The initially characterized enhancer region did not significantly alter basal or activin-stimulated murine Fshb promoter-reporter activity in homologous LβT2 cells. In contrast, the other 3 open chromatin regions enhanced basal and activin A-stimulated Fshb promoter-reporter activity in LβT2 cells, with the 2 most distal showing the greatest effects. These 2 regions were open, exhibited enrichment of the enhancer mark H3K27ac, and were bound by SMAD2/3 and FOXL2 in response to activin A in LβT2 cells. The most distal enhancer exhibited strong FOXL2 and weak SMAD4 binding in gel shift assays. SMAD4, but not FOXL2, directly bound the other distal enhancer. Mutation of defined FOXL2 and SMAD4 cis-elements diminished enhancer activity in reporter assays in LβT2 cells. Collectively, the data indicate that there may be as many as 4 activin-sensitive enhancers upstream of murine Fshb.

Animals↗

PubMed1993

Down-regulation of calcitonin gene transcription by vitamin D requires two widely separated enhancer sequences.

Transcription of the calcitonin (CT) gene is down-regulated by vitamin D in normal and transformed thyroid C cells. DNA transfer techniques have been previously used to map and characterize a cAMP-induced enhancer at nucleotides -255 to -129 and an enhancer of basal transcription at -1060 to -905 in the CT 5' flanking DNA. The same methods were used to identify a negative response element for vitamin D. Deletion mutants of a genomic fragment of CT extending from nucleotides -1460 to +90 were attached to a promoterless GH gene and transfected individually into the medullary thyroid carcinoma cell line TT. CT nucleotides -1460 to -129 induced significant basal transcription of the GH reporter gene in TT cells. Basal transcription was elevated 3-fold to 4-fold by treatment with cAMP analog. The biologically active metabolite of vitamin D3, 1,25-dihydroxyvitamin D3, had a minor (20%) inhibitory effect on basal transcription but inhibited more than 60% of the cAMP-induced transcription. We further investigated the cAMP-induced response and found that transcriptional activity of the downstream cAMP-induced enhancer was greatly synergized in the presence of the upstream enhancer of basal transcription. The latter enhancer contained three functional CANNTG sequences designated E1 (nucleotides -1060 to -1030), E2 (nucleotides -940 to -920), and E3 (nucleotides -920 to -900). E2 and E3 were essential for maximal cAMP-induced transcription. Detailed mapping of the vitamin D response showed that a minimum requirement for inhibition of the cAMP-induced enhancer by vitamin D was a sequence overlapping E3 (nucleotides -920 to -829). We conclude that a negative response element to vitamin D is located between nucleotides -920 and -829 in the CT 5' flanking DNA. It is possible that vitamin D inhibits transcription by interfering with the synergistic interaction between the cAMP-induced enhancer and the enhancer of basal transcription.

24,25-Dihydroxyvitamin D 3↗

PubMed1989

Gadolinium-DTPA-enhanced magnetic resonance imaging in childhood brain tumors.

Gadolinium DTPA (Gd-DTPA) is a paramagnetic blood-brain barrier contrast agent for MRI that has been used primarily in adults. During May through October 1987, 17 children between the ages of 3 and 18 years with brain tumors underwent MRI examinations, before and after Gd-DTPA (11 gliomas, 4 medulloblastomas, 1 craniopharyngioma, and 1 child with neurofibromatosis and no pathologic diagnosis). We compared T1 and T2 Gd-DTPA-enhanced MRI with concurrent unenhanced MRI and enhanced CT, and then correlated this with the clinical and pathologic findings. Gd-DTPA enhanced tumors in all 7 patients with newly diagnosed tumors and enhanced tumors in 7 of 10 patients without clinical evidence of progressive disease at the time of the study. In the 7 new patients, Gd-DTPA defined tumor margins in all, and demonstrated internal tumor architecture (vessels, necrosis, and cysts) in 5. Areas believed to represent surgical scars showed varying degrees of enhancement. Leptomeningeal tumor spread, including spinal, not seen on pre-Gd-DTPA MRI or on contrast CT, was evident in 2 patients. Gd-DTPA enhancement obscured hemorrhage within the tumor (methemoglobin) in 2 patients. There were no significant side effects. These results suggest that Gd-DTPA-enhanced MRI (1) is safe in children, (2) demonstrates the extent and character of tumors better than unenhanced MRI and enhanced CT, and (3) may allow for noninvasive imaging of leptomeningeal disease, including the spine, not previously demonstrated by any other noninvasive neuroimaging technique.

Adolescent↗

PubMed2002

The Drosophila Pox neuro gene: control of male courtship behavior and fertility as revealed by a complete dissection of all enhancers.

We have dissected the entire cis-regulatory region of the Drosophila Pox neuro gene with regard to its enhancers, and have analyzed their functions by the selective addition to Pox neuro null mutant flies of one or several functions, each regulated by a complete or partial enhancer. We have identified at least 15 enhancers with an astounding complexity in arrangement and substructure that regulate Pox neuro functions required for the development of the peripheral and central nervous system and of most appendages. Many of these functions are essential for normal male courtship behavior and fertility. Two enhancers regulate the development of the penis, claspers and posterior lobes of male genitalia. Three enhancers, two of which overlap, control the development of chemosensory bristles in the labellum, legs and wings, some or all of which are required for the transmission of gustatory signals elicited by female pheromones. An additional enhancer regulates in the developing brain the connectivity of two specific neuronal clusters entrusted with processing olfactory pheromone signals from the antennal nerve. Finally, functions crucial for the ability of the male to copulate depend on an enhancer that activates Pox neuro expression in the embryonic ventral cord. In addition to these male courtship and fertility functions of Pox neuro, we have identified enhancers that regulate: (1) proper segmentation of tarsal segments in the leg disc and in homologous segments of the antennal disc; and (2) proper development of the wing hinge and hence the ability of the fly to fly.

Alleles↗

PubMed2003

Information display by transcriptional enhancers.

Transcriptional enhancers integrate positional and temporal information to regulate the complex expression of developmentally controlled genes. Current models suggest that enhancers act as computational devices, receiving multiple inputs from activators and repressors and resolving them into a single positive or a negative signal that is transmitted to the basal transcriptional machinery. We show that a simple, compact enhancer is capable of representing both repressed and activated states at the same time and in the same nucleus. This finding suggests that closely apposed factor binding sites, situated within compact cis-elements, can be independently interpreted by the transcriptional machinery, possibly through successive enhancer-promoter interactions. These results provide clear evidence that the computational functions usually ascribed to the enhancer itself are actually shared with the basal machinery. In contrast to the autonomous computer model of enhancer function, an information-display or 'billboard' model of enhancer activity may better describe many developmentally regulated transcriptional enhancers.

Animals↗

PubMed1999

Estimation of the systolic pulmonary arterial pressure using contrast-enhanced continuous-wave Doppler in patients with trivial tricuspid regurgitation.

Noninvasive estimation of pulmonary arterial pressure is important for hemodynamic monitoring of patients with heart disease. In patients with tricuspid regurgitation (TR), the peak velocity of TR on continuous-wave (CW) Doppler can be used to estimate the systolic pulmonary arterial pressure (PAPs) using the simplified Bernoulli equation. We evaluated a new technique of contrast-enhanced CW Doppler for calculating PAPs in patients with trivial TR. Forty-one patients without visible TR detected by color Doppler, pulsed Doppler or CW Doppler were evaluated. Age ranged from 19 to 73 (55 +/- 12) years old. Tricuspid flow signals were recorded on CW Doppler after intravenous administration of indocyanin green (ICG) or Albunex. PAPs was calculated as; PAPs = 4 x VTR2 + 10 mmHg, where VTR is the peak velocity of TR. PAPs calculated using contrast-enhanced CW Doppler was compared with PAPs measured by the following cardiac catheterization. 1) TR signals were recorded using the contrast-enhanced CW Doppler technique in 39 of 41 patients (95%) after intravenous administration of contrast agents. 2) The error of estimate of PAPs using the contrast-enhanced CW Doppler technique was -2.4 +/- 7.5 mmHg, and the percent error was -10.7 +/- 32.4% in all patients. In 20 of 39 patients (51%), the error of estimate was within +/- 5 mmHg. 3) PAPs was overestimated by 12.2 +/- 6.1 mmHg in patients with good contrast enhancement of TR signals. The contrast-enhanced CW Doppler technique is useful for estimating PAPs noninvasively in patients with trivial TR. It is better to assume the right atrial pressure as 3-5 mmHg, not 10 mmHg, in patients with good enhancement of trivial TR. Physiological TR may be enhanced by contrast agents in these patients.

Adult↗

PubMed2005

Transgenic analysis of the stem cell leukemia +19 stem cell enhancer in adult and embryonic hematopoietic and endothelial cells.

Appropriate transcriptional regulation is critical for the biological functions of many key regulatory genes, including the stem cell leukemia (SCL) gene. As part of a systematic dissection of SCL transcriptional regulation, we have previously identified a 5,245-bp SCL +18/19 enhancer that targeted embryonic endothelium together with embryonic and adult hematopoietic progenitors and stem cells (HSCs). This enhancer is proving to be a powerful tool for manipulating hematopoietic progenitors and stem cells, but the design and interpretation of such transgenic studies require a detailed understanding of enhancer activity in vivo. In this study, we demonstrate that the +18/19 enhancer is active in mast cells, megakaryocytes, and adult endothelium. A 644-bp +19 core enhancer exhibited similar temporal and spatial activity to the 5,245-bp +18/19 fragment both during development and in adult mice. Unlike the +18/19 enhancer, the +19 core enhancer was only active in adult mice when linked to the eukaryotic reporter gene human placental alkaline phosphatase. Activity of a single core enhancer in HSCs, endothelium, mast cells, and megakaryocytes suggests possible overlaps in their respective transcriptional programs. Moreover, activity in a proportion of thymocytes and other SCL-negative cell types suggests the existence of a silencer elsewhere in the SCL locus.

Animals↗

PubMed1989

Contrast-enhanced CT of the liver and spleen: comparison of ionic and nonionic contrast agents.

We conducted a randomized, blinded, prospective study evaluating hepatic parenchymal density changes during dynamic bolus CT (180 ml of contrast material given IV) and delayed CT (5 hr after 60 g of iodine) in order to compare the enhancement characteristics of an ionic contrast agent (iothalamate-60) and two nonionic agents (iohexol-300 and iopamidol-300). A total of 75 patients with known or suspected cancer were studied (25 patients per contrast agent). After a baseline unenhanced CT scan was obtained, dynamic bolus and delayed CT scans were obtained for all patients with one of the three contrast agents. The density of the liver and spleen was measured in Hounsfield units (H) for unenhanced CT, dynamic bolus CT, and delayed CT. The average percentage of enhancement was calculated as follows: postcontrast density minus precontrast density was divided by precontrast density and then multiplied by 100. For dynamic bolus CT, the average percentage of enhancement of the liver was 105% when iohexol-300 was used, 98% when iopamidol-300 was used, and 83% when iothalamate-60 was used. No significant difference was seen between the postcontrast enhancement of the three contrast agents on dynamic bolus CT scans (p greater than .05). For delayed CT, the average percentage of enhancement of the liver was 34% when iothalamate-60 was used, 28% when iopamidol-300 was used, and 16% when iohexol-300 was used. Both iothalamate-60 and iopamidol-300 showed superior enhancement on delayed CT, compared with iohexol-300 (p = .0001). We conclude that for dynamic bolus CT, all three contrast agents are similar, with no statistically significant differences in postcontrast enhancement of the liver. For delayed CT, however, hepatic enhancement with iothalamate-60 and iopamidol-300 is statistically superior to that with iohexol-300.

Adult↗

PubMed1990

Contrast-enhanced MR imaging of the facial nerve in 11 patients with Bell's palsy.

Contrast-enhanced MR images (at 1.5 T) were obtained in 11 patients with facial palsy. The group included five people with acute idiopathic facial (Bell's) palsy, three with chronic idiopathic facial palsy, and one each with acute facial palsy after local radiation therapy, acute facial palsy resulting from herpes zoster virus infection, and facial palsy caused by facial neuroma. Eight of the 11 patients demonstrated marked enhancement of the affected facial nerve from the labyrinthine portion through the descending canal. Three patients also demonstrated mild enhancement of the distal canalicular portion of the facial nerve, simulating small distal acoustic neuromas. No difference in the pattern of enhancement between the acute or chronic Bell's palsy patients was seen. Radiographic resolution appeared to lag behind clinical resolution. The facial neuroma appeared distinct from the other lesions as a focally enhancing mass. The enhancement pattern in the Bell's group correlated with the histopathologic features of Bell's palsy and is consistent with the viral hypothesis of the syndrome. Thin-section contrast-enhanced MR scans are recommended for individuals with atypical presentation of facial paralysis. In the proper clinical setting, contrast-enhanced MR imaging may permit a positive radiographic diagnosis of Bell's palsy, which has previously been a diagnosis of exclusion.

Adult↗