Biomedical subjects

Dianna D Cody

Publications and source records attributed to Dianna D Cody.

At least 19 recordsLinked to original sources

PubMed2007

In vivo imaging of prostate cancer involving bone in a mouse model.

BACKGROUND: We compared the abilities of clinically relevant imaging modalities to quantify prostate cancer involving bone in a mouse model. Such non-invasive methods are needed pre-clinically to understand tumor biology and to evaluate therapy. METHODS: Human prostate cancer cells (MDA PCa 2b) or vehicle were injected into the right or left femur of SCID mice (n = 8). Radiography, computed tomography, and magnetic resonance imaging were performed 5 and 8 weeks later (n = 7). Bone scintigraphy (n = 6) was also performed at week 8. Imaging findings were compared with histology and correlated with contemporaneous serum prostate-specific antigen levels. RESULTS: Among the modalities evaluated, only MR imaging delineated prostate tumors involving bone. Tumor volume assessed by MR imaging correlated with PSA levels (R(2) = 0.87, P < 0.001). MR imaging of tumors corresponded with histology. Imaging of mineralized bone by CT corresponded with histology. CONCLUSION: In a mouse model, prostate tumors involving bone can be quantified using MR imaging.

Animals↗

PubMed2006

High expression of ligands for chemokine receptor CXCR2 in alveolar epithelial neoplasia induced by oncogenic kras.

CXCL8, a ligand for the chemokine receptor CXCR2, was recently reported to be a transcriptional target of Ras signaling, but its role in Ras-induced tumorigenesis has not been fully defined. Here, we investigated the role of KC and MIP-2, the murine homologues of CXCL8, in Kras(LA1) mice, which develop lung adenocarcinoma owing to somatic activation of the KRAS oncogene. We first investigated biological evidence of CXCR2 ligands in Kras(LA1) mice. Malignant progression of normal alveolar epithelial cells to adenocarcinoma in Kras(LA1) mice was associated with enhanced intralesional vascularity and neutrophilic inflammation, which are hallmarks of chemoattraction by CXCR2 ligands. In in vitro migration assays, supernatants of bronchoalveolar lavage samples from Kras(LA1) mice chemoattracted murine endothelial cells, alveolar inflammatory cells, and the LKR-13 lung adenocarcinoma cell line derived from Kras(LA1) mice, an effect that was abrogated by pretreatment of the cells with a CXCR2-neutralizing antibody. CXCR2 and its ligands were highly expressed in LKR-13 cells and premalignant alveolar lesions in Kras(LA1) mice. Treatment of Kras(LA1) mice with a CXCR2-neutralizing antibody inhibited the progression of premalignant alveolar lesions and induced apoptosis of vascular endothelial cells within alveolar lesions. Whereas the proliferation of LKR-13 cells in vitro was resistant to treatment with the antibody, LKR-13 cells established as syngeneic tumors were sensitive, supporting a role for the tumor microenvironment in the activity of CXCR2. Thus, high expression of CXCR2 ligands may contribute to the expansion of early alveolar neoplastic lesions induced by oncogenic KRAS.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2006

Quantification of bleomycin-induced murine lung damage in vivo with micro-computed tomography.

RATIONALE AND OBJECTIVES: We explored noninvasive, in vivo cone-beam microcomputed tomography (micro-CT) to visualize and quantify fibrotic and inflammatory damage over the entire lung volume of mice. MATERIALS AND METHODS: We used bleomycin to induce pulmonary damage in vivo and compared the results from micro-CT with histologic measurements. Ten C57BL/6 mice were given 5 U/kg bleomycin intratracheally. Seven surviving mice were scanned with micro-CT before administration of bleomycin, and again before sacrifice. The resulting images were analyzed for lung volume measurements. After the final scan, all lungs were examined histologically and pulmonary damage was quantified. Damaged lung tissue regions were matched between micro-CT images and histologic sections for each mouse. RESULTS: The percent lung damage calculated from micro-CT and histology were correlated (r(2) = 0.49, r = 0.64 with P = 0.12), and the means of their respective distributions were not different (P > 0.05). CONCLUSION: This study shows that micro-CT is a promising alternative to predicting lung damage caused by bleomycin. CT image volumes of the thorax allow for global tissue sampling, which may be useful when following nonuniform lung damage that can occur from intratracheal administration of bleomycin.

Animals↗

PubMed2006

Description and implementation of a quality control program in an imaging-based clinical trial.

RATIONALE AND OBJECTIVES: The American College of Radiology Imaging Network is participating in the National Lung Screening Trial, a large, multicenter, randomized controlled trial, comparing multidetector helical computed tomography (MDCT) versus chest radiography (CXR) in screening for lung cancer. Because the threshold for detection of disease is an inherent function of image quality, and consistent image quality is necessary to track changes in suspicious findings, our purpose was to develop an image quality control (QC) program across all clinical sites for both modalities. MATERIALS AND METHODS: The primary goals of the QC program include standardization of imaging protocols, certification of imaging equipment, and ongoing, periodic evaluation of the equipment calibration and image quality. Minimum standards for equipment and standardized cross-platform acquisition protocols are achieved via radiologist and physicist attestation forms and web-distributed technique charts, respectively. Imaging equipment performance standards are implemented through an initial machine certification process that includes equipment calibration. Ongoing assessment of equipment performance and calibration, as well as adherence to established imaging protocols. is accomplished via periodic submission of calibration records and phantom images. Participant-specific image acquisition parameters are entered into a web-based centralized database and variations from established protocols are automatically flagged for review. Participant radiation dose can be estimated from the image acquisition parameters applied to the imaging equipment calibration measurements. A radiologist visual review committee also evaluates participant images for diagnostic quality. Data are collected from 23 independent centers, representing 14 models of MDCT scanners from four manufacturers, and CXR systems that include film-screen, computed radiography, and direct digital radiography systems. RESULTS: Widespread imaging protocol variation in extant clinical practice-as well as variability in equipment technology, image acquisition parameters, manufacturer terminology, and user interface-have required careful standardization as a prerequisite to trial participation and ongoing image QC. Acceptable ranges for image acquisition parameters have been refined to accommodate continuously evolving equipment platforms and the scope of participant size and body habitus. CONCLUSION: Standardization of imaging protocols is a critical component of image-based clinical trials, predicated on ongoing dialogue between sites and a centralized review committee.

Artificial Intelligence↗

PubMed2006

Design and performance characteristics of a digital flat-panel computed tomography system.

Computed tomography (CT) applications continue to expand, and they require faster data acquisition speeds and improved spatial resolution. Achieving isotropic resolution, by means of cubic voxels, in combination with longitudinal coverage beyond 20 mm would represent a substantial advance in clinical CT because few commercially available scanners are capable of this at present. To achieve this goal, a prototype CT system incorporating a movable array of 20 cm X 20 cm, 200-microm-pitch amorphous silicon flat-panel x-ray detectors and a conventional CT x-ray source was constructed at the General Electric Global Research Center and performance tested at The University of Texas M. D. Anderson Cancer Center. The device was designed for preclinical imaging applications and has a scan field of 13 to 33 cm, with a magnification of 1.5. Image quality performance measurements, such as spatial and contrast resolutions, were obtained using both industry standard and custom phantoms. Spatial resolution, quantified by the system's modulation transfer function, indicated improvement by a factor of 2.5 to 5 in isotropic spatial resolution over current commercially available systems, with 10% modulation transfer function modulations at frequencies from 19 to 31 lp/cm. Low-contrast detectability results were obtained from industry-standard phantoms and were comprised of embedded contrast regions of 0.3%, 0.5%, and 1.0% over areas of several mm2. Performance was sufficient to easily distinguish 1.0% contrast regions down to 2 mm in diameter relative to the background. On the basis of scans of specialized hydroxyapatite phantoms, the system response is extremely linear (R2=0.990) in bone-equivalent density regimens. Standard CT dose index CTDI100 and CTDIw measurements were also conducted to assess dose delivery using a 16-cm-CTDI phantom and a 120 kV 120 mAs scan technique. The CTDIw ranged from 30 mGy (one-panel mode) to 113 mGy (two-panel mode) for this system. Lastly, several in vivo canine and murine samples were examined, and preliminary results from these scans are presented. On the basis of our results, it is clear that flat-panel-based CT scanners are useful for high-contrast high-resolution clinical applications, providing up to a 20-fold increase in volumetric resolution over most commercially available scanners.

Contrast Media↗

PubMed2006

Truncation artifact on PET/CT: impact on measurements of activity concentration and assessment of a correction algorithm.

OBJECTIVE: Discrepancy between fields of view (FOVs) in a PET/CT scanner causes a truncation artifact when imaging extends beyond the CT FOV. The purposes of this study were to evaluate the impact of this artifact on measurements of 18F-FDG activity concentrations and to assess a truncation correction algorithm. MATERIALS AND METHODS: Two phantoms and five patients were used in this study. In the first phantom, three inserts (water, air, bone equivalent) were placed in a water-filled cylinder containing 18F-FDG. In the second phantom study, a chest phantom and a 2-L bottle fitted with a bone insert were used to simulate a patient's torso and arm. Both phantoms were imaged while positioned centrally (baseline) and at the edge of the CT FOV to induce truncation. PET images were reconstructed using attenuation maps from truncated and truncation-corrected CT images. Regions of interest (ROIs) drawn on the inserts, simulated arm, and background water of the baseline truncated and truncation-corrected PET images were compared. In addition, extremity malignancies of five patients truncated on CT images were reconstructed with and without correction and the maximum standard uptake values (SUVs) of the malignancies were compared. RESULTS: Truncation artifact manifests as a rim of high activity concentration at the edge of the truncated CT image with an adjacent low-concentration region peripherally. The correction algorithm minimizes these effects. Phantom studies showed a maximum variation of -5.4% in the truncation-corrected background water image compared with the baseline image. Activity concentration in the water insert was 6.3% higher while that of air and bone inserts was similar to baseline. Extremity malignancies showed a consistent increase in the maximum SUV after truncation correction. CONCLUSION: Truncation affects measurements of 18F-FDG activity concentrations in PET/CT. A truncation-correction algorithm corrects truncation artifacts with small residual error.

Adult↗

PubMed2006

Breath-hold device for laboratory rodents undergoing imaging procedures.

The increased use in noninvasive imaging of laboratory rodents has prompted innovative techniques in animal handling. Lung imaging of rodents can be a difficult task because of tissue motion caused by breathing, which affects image quality. The use of a prototype flat-panel computed tomography unit allows the acquisition of images in as little as 2, 4, or 8 s. This short acquisition time has allowed us to improve the image quality of this instrument by performing a breath-hold during image acquisition. We designed an inexpensive and safe method for performing a constant-pressure breath-hold in intubated rodents. Initially a prototypic manual 3-way valve system, consisting of a 3-way valve, an air pressure regulator, and a manometer, was used to manually toggle between the ventilator and the constant-pressure breath-hold equipment. The success of the manual 3-way valve system prompted the design of an electronically actuated valve system. In the electronic system, the manual 3-way valve was replaced with a custom designed 3-way valve operated by an electrical solenoid. The electrical solenoid is triggered by using a hand-held push button or a foot pedal that is several feet away from the gantry of the scanner. This system has provided improved image quality and is safe for the animals, easy to use, and reliable.

Animals↗

PubMed2005

High expression of ErbB family members and their ligands in lung adenocarcinomas that are sensitive to inhibition of epidermal growth factor receptor.

Recent findings in tumor biopsies from lung adenocarcinoma patients suggest that somatic mutations in the genes encoding epidermal growth factor receptor (EGFR) and Kirsten ras (KRAS) confer sensitivity and resistance, respectively, to EGFR inhibition. Here, we provide evidence that these genetic mutations are not sufficient to modulate the biological response of lung adenocarcinoma cells to EGFR inhibition. We found high expression of ErbB family members, ErbB ligands, or both in three models that were sensitive to EGFR inhibition, including alveolar epithelial neoplastic lesions in mice that develop lung adenocarcinoma by oncogenic KRAS, human lung adenocarcinoma cell lines, and tumor biopsies from lung adenocarcinoma patients. Thus, lung adenocarcinoma cells that depend on EGFR for survival constitutively activate the receptor through a combination of genetic mutations and overexpression of EGFR dimeric partners and their ligands.

Adenocarcinoma↗

PubMed2005

Inhibition of prostate cancer-meditated osteoblastic bone lesions by the low-calcemic analog 1alpha-hydroxymethyl-16-ene-26,27-bishomo-25-hydroxy vitamin D3.

Prostate cancer metastasizes almost exclusively into the bone whereby it induces primarily an osteoblastic response. Non-calcemic vitamin D analogs have been shown to inhibit proliferation of prostate cancer cells in culture and inhibit their growth as subcutaneous xenografts in mice. However, their effect on prostate cancer cell growth in the bone has not been examined. In the present study, we inoculated the osteoblastic prostate cancer cell line MDA-PCa 2b into the bone of male SCID mice and examined the effect of the low-calcemic hybrid analog 1alpha-hydroxymethyl-16-ene-26,27-bishomo-25-hydroxy vitamin D(3) (JK-1626-2) on their ability to induce bone lesions. We found that 7 weeks after inoculation of MDA-PCa 2b cells, 90% of the mice in the vehicle-treated group had significant bone lesions that were detectable by micro-computed tomography and characterized by thickening of the cortical bone and ossification of the epiphysis. Only 30% of the mice in the analog-treated group (daily injections of 4microg/kg, 5 days/week for up to 7 weeks) had detectable bone lesions. Histological examination of the decalcified tumor-bearing bones has shown that tumor cells completely replaced the bone marrow in the diaphysis, and destroyed the trabecular bone in the metaphysis in 90% of the vehicle-treated mice. In contrast, the metaphysis of 60% of analog-treated mice appeared normal, although tumor cells were still found in the diaphysis of 70% of the bones in the analog-treated group. There was no evidence of hypercalcemia in any of the analog-treated mice. In a co-culture, MDA-PCa 2b cells induced a profound mitogenic response in osteoblasts followed by enhanced differentiation. However, in the presence of the analog the mitogenic response of the osteoblasts to the malignant cells was significantly attenuated. These experiments led to the hypothesis that, in vivo, JK-1626-2 prevented the metastatic bone lesions by inhibiting the mitogenic response of osteoblasts to growth factors produced by MDA-PCa 2b cells.

Animals↗

PubMed2005

Multi-detector row CT artifacts that mimic disease.

PURPOSE: To determine retrospectively the frequency of two artifact patterns that mimic pathologic lesions on computed tomographic (CT) head images acquired in the axial scanning mode with two different multi-detector row CT systems at the same institution. MATERIALS AND METHODS: The institutional review board approved this Health Insurance Portability and Accountability Act-compliant study and waived informed consent. The study involved two groups of consecutive patients, a group of 22 (nine men, 13 women; mean age, 56 years; age range, 27-85 years) examined with one multi-detector row CT system with four detector rows, and another group of 13 (seven men, six women; mean age, 69 years; age range, 53-81 years) examined with a different four-detector row CT system. Examinations in each group took place in a 4-week period. CT images were retrospectively evaluated by a neuroradiologist and a physicist for presence, appearance, location (within the image set and on individual images), and size of artifacts. Elimination of artifacts was verified by scanning a water phantom after scanner service and repair. RESULTS: A pseudolesion, or artifact, was identified in scans of four of 22 patients examined with the first scanner and eight of 13 patients examined with the second scanner. The artifact on images obtained on the first scanner, an approximately 2-cm-diameter faintly hyperattenuating and nonenhancing area with hypoattenuating collar, was found at gantry isocenter on every fourth image. A different pattern was found on images obtained on the second scanner: a 1.1-cm-diameter circular area of hypoattenuation with a faintly attenuating rim, that mimicked a cyst. This artifact was observed also at the CT scanner gantry isocenter on every fourth image. Artifacts disappeared after recalibration (first scanner) or collimator cleaning (second scanner). CONCLUSION: CT scanning in the axial mode can produce a regularly repeating artifact when data from one detector row of a multi-detector row CT scanner are compromised. Because of the risk of misinterpreting such patterns, routine assessment of each detector element is recommended for multi-detector row CT scanners that are routinely used in the axial scanning mode.

Adult↗

PubMed2005

Inhibition of mammalian target of rapamycin reverses alveolar epithelial neoplasia induced by oncogenic K-ras.

The serine/threonine kinase AKT and its downstream mediator mammalian target of rapamycin (mTOR) are activated in lung adenocarcinoma, and clinical trials are under way to test whether inhibition of mTOR is useful in treating lung cancer. Here, we report that mTOR inhibition blocked malignant progression in K-ras(LA1) mice, which undergo somatic activation of the K-ras oncogene and display morphologic changes in alveolar epithelial cells that recapitulate those of precursors of human lung adenocarcinoma. Levels of phospho-S6(Ser236/235), a downstream mediator of mTOR, increased with malignant progression (normal alveolar epithelial cells to adenocarcinoma) in K-ras(LA1) mice and in patients with lung adenocarcinoma. Atypical alveolar hyperplasia, an early neoplastic change, was prominently associated with macrophages and expressed high levels of phospho-S6(Ser236/235). mTOR inhibition in K-ras(LA1) mice by treatment with the rapamycin analogue CCI-779 reduced the size and number of early epithelial neoplastic lesions (atypical alveolar hyperplasia and adenomas) and induced apoptosis of intraepithelial macrophages. LKR-13, a lung adenocarcinoma cell line derived from K-ras(LA1) mice, was resistant to treatment with CCI-779 in vitro. However, LKR-13 cells grown as syngeneic tumors recruited macrophages, and those tumors regressed in response to treatment with CCI-779. Lastly, conditioned medium from primary cultures of alveolar macrophages stimulated the proliferation of LKR-13 cells. These findings provide evidence that the expansion of lung adenocarcinoma precursors induced by oncogenic K-ras requires mTOR-dependent signaling and that host factors derived from macrophages play a critical role in adenocarcinoma progression.

Adenocarcinoma↗

PubMed2005

Murine lung tumor measurement using respiratory-gated micro-computed tomography.

OBJECTIVE: The authors explored micro-computed tomography (micro-CT) to quantify lung tumor number and volume in a specific genetic mouse model for lung cancer. MATERIALS AND METHODS: The authors used K-ras mice, which develop lung adenomas and adenocarcinomas through somatic activation of the K-ras oncogene. Tumor number measured using micro-CT and were compared at necropsy (n = 38 mice). Tumor volume measurement precision (n = 39 mice) and accuracy (multiple tumors from a single mouse) were evaluated. Serial lung tumor volume was assessed in a pilot group (n = 8) of mice in vivo. RESULTS: Tumor number assessed at necropsy and using micro-CT were significantly correlated. Lung tumor volume measurements were both reproducible (2% operator variability) and accurate (6% average error). Strikingly, we observed both tumor growth and shrinkage within individual mice. CONCLUSION: Serial measurements provided evidence of tumor heterogeneity, an unexpected finding given the uniformity of the initiating genetic event. Micro-CT may become a powerful tool for murine lung cancer research in vivo.

Adenocarcinoma↗

PubMed2005

c-Jun N-terminal kinase contributes to aberrant retinoid signaling in lung cancer cells by phosphorylating and inducing proteasomal degradation of retinoic acid receptor alpha.

Retinoic acid (RA) is the ligand for nuclear RA receptors (RARs and RXRs) and is crucial for normal epithelial cell growth and differentiation. During malignant transformation, human bronchial epithelial cells acquire a block in retinoid signaling caused in part by a transcriptional defect in RARs. Here, we show that activation of c-Jun N-terminal kinase (JNK) contributes to RAR dysfunction by phosphorylating RARalpha and inducing degradation through the ubiquitin-proteasomal pathway. Analysis of RARalpha mutants and phosphopeptide mapping revealed that RARalpha residues Thr181, Ser445, and Ser461 are phosphorylated by JNK. Mutation of these residues to alanines prevented efficient ubiquitination of RARalpha and increased the stability of the protein. We investigated the importance of RARalpha phosphorylation by JNK as a mediator of retinoid resistance in lung cancer. Mice that develop lung cancer from activation of a latent K-ras oncogene had high intratumoral JNK activity and low RARalpha levels and were resistant to treatment with an RAR ligand. JNK inhibition in a human lung cancer cell line enhanced RARalpha levels, ligand-induced activity of RXR-RAR dimers, and growth inhibition by RA. These findings point to JNK as a key mediator of aberrant retinoid signaling in lung cancer cells.

3T3 Cells↗

PubMed2005

Reducing radiation exposure from survey CT scans.

OBJECTIVE: The purpose of this study was to focus attention on the technique factors commonly used in survey CT scans (e.g., scout, topogram, or pilot scans) to measure the radiation exposure from typical survey CT scans, to compare their exposure to that of typical chest radiographs, and to explore methods for radiation exposure reduction. MATERIALS AND METHODS: The default survey CT scans on 21 CT scanners, representing three different vendors and 11 different models, were investigated. Exposure measurements were obtained with an ion chamber at isocenter and adjusted to be consistent with standard chest radiographic exposure measurement methods (single posterior-anterior projection). These entrance exposures were compared with those of typical chest radiographs, for which the mean for average-sized adults is 16 mR (4.1 x 10(-6) C/kg). RESULTS: The entrance exposures of the default survey CT scans ranged from 3.2 to 74.7 mR (0.8 to 19.3 x 10(-6) C/kg), which is equivalent to approximately 0.2 to 4.7 chest radiographs. By changing the default scan parameters from 120 kVp to 80 kVp and the tube position from 0 degrees (tube above table) to 180 degrees (tube below table), the entrance exposure for the survey CT scan was reduced to less than that of one chest radiograph for all CT scanners. CONCLUSION: For institutions at which the interpreting radiologists do not rely heavily on the appearance of the survey CT image, we recommend adjusting the technique parameters (kilovoltage and X-ray tube position) to decrease radiation exposure, especially for vulnerable patient populations such as children and young women.

Adult↗

PubMed2005

Intraperitoneal administration of an iodine-based contrast agent to improve abdominal micro-computed tomography imaging in mice.

The purpose of this study was to estimate the optimal volume of an iodine-based contrast agent to administer to mice via intraperitoneal injection and the optimal time after injection to perform micro-computed tomography for maximal enhancement of abdominal organs. Eight mice were paired randomly; three pairs underwent imaging after receiving intraperitoneal injections of 125, 250, or 500 microl of contrast agent, and the fourth pair underwent imaging without receiving an injection. Each mouse was scanned three consecutive times, and each scan lasted 25 min so that we could observe the clearance of the contrast agent from the abdomen. We determined that introducing 250 microl of contrast agent into the abdominal cavity of the mice and then having the mice undergo micro-computed tomography 15 min after injection provided the optimal degree of contrast enhancement needed to distinguish the abdominal organs. These results may lead to expanded use of this imaging modality to assess abdominal organ margins in small-animal studies in vivo.

Animals↗

PubMed2004

Improved method of in vivo respiratory-gated micro-CT imaging.

The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This procedure involves the use of a ventilator that controls the respiratory cycle of the animal and provides a digital output signal that is used to trigger data acquisition. After inspection of the default respiratory trigger timing, we hypothesized that image quality could be improved by moving the data-acquisition window to a portion of the cycle with less respiratory motion. For this reason, we developed a simple delay circuit to adjust the timing of the ventilator signal that initiates micro-CT data acquisition. This delay circuit decreases motion artifacts and substantially improves image quality.

Algorithms↗

PubMed2004

The distal femoral and proximal tibial growth plates: MR imaging, three-dimensional modeling and estimation of area and volume.

OBJECTIVE: To explore how the size of the growth plate changes with age using three-dimensional (3D) models of the distal femoral and proximal tibial growth plates in pediatric patients. DESIGN AND PATIENTS: We retrospectively created 3D models of the normal unaffected distal femoral (n=20) and proximal tibial (n=10) growth plates in 14 patients (9 males, 5 females) age range 3.8-15.6 years who were referred for evaluation of premature partial closure of the growth plate or hyaline cartilage abnormality. All patients had one or more 3D fat-suppressed spoiled GRASS sequence from which models were made of normal growth plates. Total projected area was estimated from standardized maximum intensity projection (MIP) views, and volume was computed from the entire model. We also included the total projected area of the distal femur (n=7) or proximal tibia (n=8) in 11 patients (8 males, 3 females, 5-13 years) who had previously been evaluated for bone bridging. RESULTS: The 3D femoral and tibial growth plate anatomy was displayed. Femoral growth plate area varied from 804 mm2 to 3,463 mm2. Femoral physeal cartilage volume varied from 2.1 cm3 to 12.6 cm3. Tibial growth plate area varied from 736 mm2 to 3,026 mm2. Tibial physeal cartilage volume varied from 1.9 cm3 to 13.2 cm3. The growth plate area values appear to increase linearly with increasing age. CONCLUSIONS: The distal femoral and proximal tibial physeal plates have complex anatomy. Both area and volume of the growth plates appeared to follow a linear increase with age and reached a plateau in adolescence, although there was some scatter. Area appears to have less measurement variability than volume, and may be a more reliable predictor of growth plate tissue quantity.

Adolescent↗

PubMed2004

Comparison of cross-sectional geometry of the proximal femur in white and black women from Detroit and Johannesburg.

UNLABELLED: There are known black-white differences in bone density measured by DXA but less is known about bone architecture. We compared cross-sectional geometric properties of the proximal femur in U.S. black (n = 86) and white (n = 151) and South African black (n = 60) and white (n = 48) postmenopausal women. Results are consistent with greater bone strength in the black groups in both countries. INTRODUCTION: There are well-known ethnic differences in bone density, but little is known about ethnic differences in bone architecture between U.S. and South African blacks and whites. MATERIALS AND METHODS: We compared bone density and cross-sectional geometric properties of the proximal femur in 237 U.S. black (n = 86) and white (n = 151) and 108 South African black (n = 60) and white (n = 48) postmenopausal women. The proximal femur (neck, intertrochanteric region, and proximal shaft regions of interest) was measured with DXA and further analyzed with a hip structural analysis program. For each region, BMD, cross-sectional area, outer diameter, section modulus, endosteal diameter, average cortical thickness, and the buckling ratio were estimated. RESULTS AND CONCLUSIONS: In the femoral neck, in both countries, the blacks had narrower endosteal diameters (mean difference, 2.6% and 5.1% in U.S. and South African women, respectively), thicker cortices (9.3% and 11.0%), and a lower buckling ratio (11.6% and 15.2%) despite a similar outer diameter. In the intertrochanteric region, the whites had a greater outer diameter (2.2% and 3.0% in U.S. and South African women, respectively), lower cross-sectional area (4.8% and 7.2%), and a higher buckling ratio (7.6% and 3.6%). There are fewer differences in the shaft. Compared with South African whites, U.S. whites had wider (mean difference 2.9%) femoral necks and a greater section modulus (6.4%) in the shaft. U.S. whites also had greater cross-sectional area in both the neck and shaft (5.2% and 4.6%, respectively). The U.S. blacks had significantly greater outer diameters, cross-sectional areas, endosteal diameters, and section moduli in the neck region compared with South African blacks. Our observations are consistent with greater bone strength in the black groups in both countries, and they also suggest that there are fewer differences between the same ethnic groups in the two countries than there are between different ethnic groups within a country.

Black or African American↗