Quantitative evaluation of the relation between bone mass of the metacarpal bone and bone mineral content of the forearm in normal persons and patients with chronic renal failure before and after kidney transplantation

Twenty-seven healthy normal subjects, 30 non-dialyzed patients with chronic renal failure, 25 hemodialyzed patients on chronic hemodialysis, and 54 renal transplant recipients were evaluated simultaneously with regard to a correlation between the bone mineral content of the forearm and the total cortical thickness and area of the second left metacarpal bone. A significant correlation was found between bone mineral content of the forearm and the cortical bone mass of the metacarpal bone in normal subjects and in the patient groups.     

Continuing loss of vertebral mineral density in renal transplant recipients

This cross-sectional study examined bone abnormalities by digital radiography, bone densitometry and biochemical tests in 44 clinically asymptomatic renal transplant recipients 6–195 months after renal transplantation. Abnormal radiographs were obtained in 40 of the 44 patients. Dual-energy X-ray absorptiometry (DXA) performed at the lumbar spine (L2–L4)/showed a negative Z score in all patients, ranging from –1 to –1.9 in 28 patients and less than –2.0 in 16 patients. The severity of osteopenia increased with the length of time after transplantation and there was a significant correlation with parathyroid hormone values in patients with normal and low glomerular filtration rates. Our data suggest that decreased bone density values (Z score less than –2) are present in about one-third of patients with renal transplants. Bone loss appears to continue after transplantation. Steroid therapy and immunotherapy are probably the cause of this bone loss. Bone mineral measurements alone are helpful in identifying asymptomatic patients with low bone mass after transplantation. Correspondence to: B. Bagni     

肾移植术后患者骨密度水平的调查研究

 目的 探讨肾移植术后患者与正常体检人群骨密度(bone mineral density, BMD)水平,以及骨量丢失(骨量减少和骨质疏松)发病率的差异。方法 选择在武警总医院随访的肾移植患者177例(男104例,女73例),根据女性是否绝经和男性年龄将入选者分为＜50岁男性、≥50岁男性、绝经前女性和绝经后女性移植组。选择同期在我院体检的正常人群250例(男131例、女119例)作为对照组。采用双能X线骨密度仪测定所有人的腰椎、右股骨颈和右全髋BMD,比较各移植组与对照组BMD以及骨量丢失发病率的差异。结果 各肾移植组患者股骨颈和全髋骨密度均低于对照组(P<0.01);＜50岁男性肾移植患者腰椎骨密度低于对照组(P<0.01)。男性和绝经后女性移植患者骨量丢失(包括骨量减少和骨质疏松)发病率显著高于对照组(P<0.01)。结论 肾移植患者骨密度水平明显低于正常体检人群,且骨量丢失的发病率高于正常人群。建议肾移植患者术后在维生素D和钙剂的基础上,选用双膦酸盐防治骨质疏松和骨折。     

Quantitative assessment of mineral content in metacarpal bone with Fuji computed radiography

A new microdensitometry method for quantitative assessment of bone mineral content using Fuji computed radiography (FCR) was developed and the results were compared with those obtained by the conventional film-screen method. Using both methods, X-ray pictures of the 2nd metacarpal bone were taken with a reference aluminum step wedge in nine normal subjects and nine parameters representing the width and density of bone marrow and cortex were calculated in the middle of the bone shaft. Interobserver reproducibility assessed for three parameters was significantly higher in the FCR method than the conventional one. The value of sigma GS computed by the FCR method, that is equivalent to the net bone density of the transverse section of the shaft, showed higher correlation with the one obtained by computed tomography in comparison with the conventional method. In our FCR method, moreover, interobserver reproducibility and accuracy was improved by employing automatic manipulation as much as possible in the process of calculation. The exposure dose in the FCR method could be reduced to half of the one in the conventional method without deteriorating the accuracy. In conclusion, our new microdensitometry method with FCR provides high accuracy and good reproducibility for the measurement of bone mineral content with small exposure dose and is likely to be useful for the long-term follow-up of the osteoporotic patients from the variety of causes.     

Factors affecting bone mineral density in renal transplant patients

Bone disease is a major cause of morbidity in end stage renal failure. This study is aimed to assess the prevalence of abnormal bone mineral density (BMD), measured by dual photon absorptiometry (DPA) in the renal transplant population. Subjects consisted of 110 patients followed up after transplantation for between 1 and 17 years. Variables analyzed included age, sex, ethic origin, years and type of dialysis prior to transplantation, date of transplant, total steroid dose, number of rejection episodes, use of Cyclosporin, and biochemical/hormonal variables such as serum calcium, phosphate, magnesium, alkaline phosphatase, creatinine, FSH, LH and PTH. Analysis of variance and chi square tests were performed to assess the differences between groups and Pearson correlation coefficients were obtained. The total steroid dose, year of birth, PTH level and duration since transplantation were correlated with BMD (p < 0.05). Despite the statistical significance, the degree of variability indicated by each of these variables was low revealed by multiple regression analysis. We conclude that although steroid therapy is a major contributor to the increase in osteoporosis in renal transplant patients, about two thirds of the parameters that can influence bone metabolism remain unexplained.     

Indexes of bone mineral content on second metacarpal bone roentgenogram analyzed by digital image processing: a comparison with other bone mass quantifying methods

A new photodensitometric technique (digital image processing, DIP) was performed to assess the bone mineral content of the metacarpal bone as a screening test for bone loss in 340 healthy or osteoporotic women as well as 35 steroid-dosed patients and 46 patients with chronic renal failure on hemodialysis. This procedure was compared with single photon absorptiometry and dual photon absorptiometry in terms of clinical value. Two bone mineral indexes, metacarpal index and sigma GS/D (the integrated bone mineral density of cortical and trabecular bone on a cross section in the middle of the second metacarpal bone), were equal to other methods in the quantification of decreases in bone mineral content due to aging in healthy or osteoporotic women. In addition, sigma GS/D was sensitive enough to detect decreases in bone mineral content in patients with vertebral fractures, on steroid therapy, and with chronic renal failure. Thus, sigma GS/D measured by DIP was shown to have clinical value as a tool in screening for decreased bone mineral content.     

Assessment of bone mineral content and bone mass by non-invasive radiologic methods

Methods for quantitative determination of bone mineral and bone mass in normal subjects and in patients with metabolic bone disorders can be measured by the Compton scattering technique, the neutron activation analysis, by measurement of metacarpal bone mass, by single and dual photon absorptiometry, and by quantitative computed tomography. Measurement on metacarpal bone (radiogrammetry) seems to be able to distinguish between resorption and/or new bone formation at the periosteal and/or endosteal surface. The intraindividual observer variation on combined cortical thickness (D-d), cortical area (D2-d2), metacarpal bone mass (D2-d2)/D2-varies from 0.7 to 2.5 per cent and the interindividual observer variation from 1.0 to 5.8 per cent. Single photon absorptiometry measures bone mineral content in the forearm with great precision. The reproducibility using repeated measurements and automatic selection of the measuring area is about one per cent and can be used to follow changes in mineral content with time in patients with metabolic bone diseases. The dual photon absorptiometry may be used for measurements of bone mineral content in lumbar spine, in the femoral neck and measurement of total body calcium with an accuracy of less than 6 per cent and a precision below 3 per cent. Quantitative computed tomography has the ability to measure trabecular and cortical bone both centrally and peripherally. Using CT scanning, scanner related changes with time (day-to-day variation +/- 4%), patient repositioning (less than 1.5%), and fat concentration (residual uncertainty of approximately 1/6 of the biologic variation) are important factors influencing the accuracy and reproducibility of the values of the measured bone mineral content.(ABSTRACT TRUNCATED AT 250 WORDS)     

Digital subtraction angiography in renal transplant recipients

The renal transplant vascularity of 72 patients was investigated by intravenous digital subtraction angiography (IV DSA). The procedure was combined with selective venous renin sampling of the transplant and native kidneys to identify the source of hypertension in these patients. Abnormalities were found on IV DSA examination in 26 patients, of whom 7 had graft artery stenosis, 7 had diffuse intrarenal narrowing, 9 had lower pole ischemia, and 3 had aneurysmal dilatation. The combined outpatient procedure was well tolerated by all patients with no complications nor incidence of proteinuria.     

Quantitative metacarpal bone measurements before and after renal transplantation

The outer (D) and inner diameter (d) of the second metacarpal bone, the combined cortical thickness (D-d), cortical area (D2-d2) and bone mass [D2d2)/D2) were measured in 74 renal transplant (RT) recipients at the time of renal transplantation and in a prospective analysis of 60 recipients after transplantation. The RT patient group was made up of recipients who after renal transplantation developed osteonecrosis or spontaneous fractures (RT-ON/SF) and an age- and sex-matched renal control group of subjects who did not develop these complications (RT-C). At the time of renal transplantation, in renal transplant recipient men and women, significantly reduced values in D, D-d and D2-d2 was noticed. These findings could be explained by a higher ratio of bone resorption than formation at the periosteal surface. Following renal transplantation, significant increases in d were seen with significant decreases in D-d, D2-d2 and (D2-d2)/D2, probably due to endosteal bone resorption, whereas D was unchanged compared with normal control persons. In the total group and in RT-ON/SF women, D decreased significantly and in ON/SF, increased significantly with significant decrease in bone mass compared with normal women whereas no significant changes in the parameters were seen in RT-C women. These findings indicate that bone loss after transplantation continues at the periosteal surface in women. The bone loss was most markedly demonstrated in women, who subsequently develop osteonecrosis or spontaneous fractures, probably due to a combined periosteal and endosteal resorption of calcified bony tissue.     

The relation between sub-capital fracture of the femur and mineral content of the right third metacarpal.

Positive correlation between the mineral content of the mid site of right third metacarpal and neck of femur has been established using the psi-ray absorption technique described by Shimmins et al. (1972b) to make measurements on excised human bones. An X-ray method (Anderson, Shimmins and Smith, 1966; Shimmins et al. 1972a) was used to measure the mineral content of the right third metacarpal in 101 female and 22 male patients with subcapital fracture of the ferum. When their metacarpal "whole bone densities" were compared with those of control subjects of the same age and sex, they were found to have significantly lower (P smaller than (0.025) average values. However, groups of patients defined according to Garden's classification of severity of fracture could not be distinguished one from the other on the basis of metacarpal whole bone density measurement.     

Low-dose-rate brachytherapy for prostate cancer in renal transplant recipients

PURPOSEProstate cancer (PCa) is the most common malignancy among men and one of the most common neoplasms affecting renal transplant recipients (RTRs). The available treatments for localized PCa among the general population (GP), surgery and external beam radiotherapy, carry a risk of damage to the transplanted kidney, the ureters, and the bladder and therefore tend to be avoided by most groups. The objective of this study was to assess the efficacy and feasibility of low-dose-rate brachytherapy (LDR-BT) for PCa in RTRs.METHODS AND MATERIALSWe carried out a retrospective review on all RTRs diagnosed of PCa who had undergone LDR-BT at our institution between 2000 and 2015. Nine patients met these criteria, but 1 did not fulfill the followup. Hence, we analyzed 8 patients. We reviewed all clinical data for PCa and graft function in these patients and compared the results with the GP.ResultsMean baseline prostate-specific antigen was 6.8 ± 1.9 ng/mL. All PCa had a Gleason score of 6 and were classified as low risk according the Europe Association of Urology guidelines. Mean followup after seed implantation was 48 ± 12.8 months. All 8 patients remain free of prostate-specific antigen failure. Five-year progression-free survival, cancer-specific survival, and overall survival rates were 100%, 100%, and 62.5%. There was no specific toxicity associated with LDR-BT, and there were no acute adverse events affecting the graft.ConclusionsLDR-BT is a feasible and acceptable treatment for localized PCa in RTRs. Oncological outcomes are similar to the GP, and there is minimal toxicity to the renal graft.     

Cyclosporin-A nephrotoxicity and acute cellular rejection in renal transplant recipients: correlation between radionuclide and histologic findings

Serial radionuclide studies using both Tc-99m DTPA (perfusion) and I-131 hippuran (tubular function) were correlated with histologic findings in 25 patients with renal transplants. These cases included 15 cases of cyclosporin-A nephrotoxicity (CsA-NT) and ten cases of acute cellular rejection that were retrospectively selected on the basis of biopsy findings and favorable clinical response to therapy specific for each of these conditions. The serial radionuclide studies enabled the correct diagnosis in 12 of 15 cases of CsA-NT and eight of ten cases of acute rejection. Posttherapy radionuclide studies, furthermore, demonstrated improvement consistent with clinical response. In all cases, the radionuclide results were available at least 24 hours before biopsy findings. These results indicate that serial radionuclide studies evaluating interval changes in both perfusion and tubular function are of significant value in the diagnosis and follow-up of CsA-NT and acute cellular rejection in transplant recipients. This initial experience suggests a sensitivity of 80%.     

FK 506与CsA在肾移植术后抗排斥的临床应用

 目的 比较研究他克莫司(FK 506)与环孢素A(CsA)预防肾移植术后排斥反应的效果和安全性。方法 肾移植患者53例分成两组,FK506始用组为28例,CsA始用组为25例。FK506起始用每d0.2mg／kg,CsA起始用每d6mg／kg,用时合并应用MMF0.75g,2／d,以及术后3d大剂量甲基强的松龙(MP)静滴,第3d改强的松口服。结果 FK506始用组移植肾功能好,平均7.5d肌酐水平平均降至99.5μmol／L,2例出现排斥反应,经MP连续3d冲击后治愈,CsA始用组19例移植肾功能良好。结论 肾移植术后应用FK506疗效确切,能有效防治难治性排斥的发生,降低急性排斥的发生率,特别是乙肝表面抗原阳性 肝功能受损者比CsA优越。     

MRI findings in renal transplant recipients with hip and knee pain

Purpose

To evaluate and demonstrate the MRI findings of renal transplant recipients with hip and knee pain and to investigate the most common etiology of pain.

Materials and methods

69 hip MRIs of 57 patients with hip pain and 30 knee MRIs of 24 patients with knee pain with no history of trauma were retrospectively evaluated by two radiologists.

Results

In the evaluation of hip MRIs, 24 patients had avascular necrosis and effusion, 2 patients had bone marrow edema consistent with early stage of avascular necrosis. 18 patients had only intraarticular effusion, 6 patients had tendinitis, 6 patients had bursitis and 1 patient had soft tissue abscess. Five patients had muscle edema and five patients had muscle atrophy as additional findings to the primary pathologies. Among patients with knee pain, nine patients had degenerative joint disease. Seven patients had chondromalacia, five had bone marrow edema, six had meniscal tear, six had ligament rupture and two had bone infarct. Three of the patients had muscle edema accompanying to other pathologies.

Conclusion

The most common etiology of hip pain in renal transplant recipients is avascular necrosis as expected, intraarticular effusion is found to be the second reason for pain. However, knee pain is explained by ligament pathology, meniscal tear, chondromalacia or degenerative joint disease rather than osteonecrosis.     

Assessment of bone mineral content in the internal bone volume

A method for assessing values related to bone density and mass is described. Mean attenuation and pixel area are measured in pixels selected on the basis of CT units. The method is to a large extent computerized and not dependent on manual positioning or outlining of a region of interest. Because it is not dependent on a comparatively large volume of homogeneous bone it can be used to make assessments even in very heterogeneous bones including cortical bone. The method is adaptable for measurement in all parts of the skeleton and values related to both bone density (DRV) and bone mass (MRV) are derived. The measurements in the femoral condyles were shown to have a precision of approximately 0.25 to 0.30 Z-score units (standard deviation of the measurements expressed in Z-score units). The agreement between chemically analyzed calcium density (weight of calcium per volume) and DRV was little less than 0.50 Z-scores and 0.30 Z-scores for the chemically determined calcium mass and the MRV. The agreement with mechanical bone strength was 0.78 Z-scores for DRV and 0.64 for the MRV. Altering scan parameters or measuring approaches gave systematic differences in measurements. There were, however, good linear correlations between the measurements which show that these different measuring approaches essentially gave identical measurements.     

Correlations between peripheral and central skeletal mineral content in chronic renal failure patients and in osteoporotics

Partial-body calcium measurements by in vivo neutron activation analysis (IVNAA) were correlated with radiographic measurements of bone mineral mass and density, external diameter, and combined cortical thickness of the proximal radius in three groups of subjects: normals, osteoporotics, and chronic renal failure patients. The radial bone mineral mass (in g/cm) correlated best with IVNAA measurements in normal subjects (r=0.94), reasonably well in osteoporotics (r=0.83), and less well in chronic renal failure patients (r=0.65). Simple combined cortical thickness measurements correlated moderately well both in normal subjects (r=0.82) and in osteoporotic subjects (r=0.74).     

Radiological determination of changes in bone mineral content

It is possible to obtain reliable data of changes in bone mineral content using simple radiographic techniques. Methods available include morphometry and densitometry. Of these morphometry of the third metacarpal is most accurate in our hands and cortical width is the most reliable of such morphometric data. Densitometry produces more variable results and shows no advantage over straight measurement of cortical width. The only acceptable alternative method of obtaining information about bone status is photon absorptiometry. Results of these methods are shown in a trial of oestrogen therapy for the prevention of post-menopausal osteoporosis. The data suggest that oestrogens prevent post menopausal bone loss when this is estimated by measurement of cortical width or photonabsorptiometry.