Bone scan in chronic dialysis patients with evidence of secondary hyperparathyroidism and renal osteodystrophy

Skeletal Metastases Presenting as Superscan on Technetium 99m Methylene Diphosphonate Whole Body Bone Scintigraphy in Different Type of Cancers: A 5-Year Retro-prospective Study

The purpose of the study is to find out the overall incidence of superscan among different type of cancers, causes of superscan and its relationship with other parameters such as age, sex, duration of disease, and serum alkaline phosphatase (ALP) levels. This was a retro-prospective study. Records of all previous bone scans and reported patients of superscan were re-evaluated retrospectively. Patients who were diagnosed as having superscan in the preceding 3 years with confirmed histopathological diagnosis were included in the retrospective group. In the prospective group, all the patients who were reported to have superscan appearance over the past 2 years of prospective period were included. Total of 6027 bone scans were examined in a 5-year period and out of which 80 cases were diagnosed as superscan. The overall incidence of superscan in different type of cancers was 1.3% (80/6027). Prostate cancer (46/80) was the most common cause of superscan appearance followed by breast cancer (10/80). Out of 6027 patients referred for bone scan, 307 patients had prostate cancer on histopathological examination. Out of 307 patients with prostate cancer, 46 had superscan appearance. Incidence of superscan in prostate cancer was 14.98% (46/307), and 71.73% (33/46) prostate cancer patients with superscan had Gleason score of 8 and above 8 with mean serum prostate-specific antigen level was 178.42 ng/ml in symptomatic patients and 122 ng/ml in asymptomatic patients. Out of all patients with superscan, 71 patients (88.7%) had elevated serum ALP levels. Overall incidence of superscan in our study was 1.3% in different type of cancer patients, and the most common cause of superscan appearance was prostate cancer. Incidence of superscan appearance in prostatic cancer patients was 14.98%.

99mTc bone scintigraphy superscans: a review

Whole-body bone scintigraphy (bone scan) using a (99m)Tc-labelled pharmaceutical is one of the most commonly performed radionuclide examinations. In the normal patient, both the osseous components of the skeletal system as well as the kidneys and bladder are visualized. A superscan is defined as a bone scan which demonstrates markedly increased skeletal radioisotope uptake relative to soft tissues, in association with absent or faint genito-urinary tract activity. While a superscan is relatively uncommon, its recognition is important, as it is associated with a number of important underlying diseases. The purpose of this review article is to describe the causes and variable features of a superscan and depict patterns which may aid in defining the underlying cause for the scan. In addition, we will discuss other investigations that may help further to identify the underlying disease in such cases.

A clinical assessment of the relationship between bone scintigraphy and serum biochemical markers in hemodialysis patients

BACKGROUND

Renal osteodystrophy is a metabolic bone disease and a common complication of end-stage chronic renal failure and maintenance dialysis treatment. In this study, we examined the correlation between quantifying bone scintigraphy and serum biochemical markers in hemodialysis patients.

METHODS

Bone scintigraphy with technetium-99m-hydroxy-methylene-diphosphonate (99mTc-HMDP) was performed on 28 patients on maintenance hemodialysis. Bone scintigraphy was performed using a standard protocol and was quantified by setting regions of interest (ROIs) over selected regions. The bone-to-soft-tissue ratio (B/ST ratio) at each region was calculated in all patients. The B/ST ratios were then compared with serum biochemical markers.

RESULTS

The B/ST ratio for the skull correlated well with serum bone-specific alkaline phosphatase (BAP) (r = 0.735, p < 0.001), serum deoxypyridinoline (DPD) (r = 0.806, p < 0.001) and intact parathyroid hormone (intact PTH) (r = 0.701, p < 0.001). The B/ST ratio for the lumbar spine correlated with intact PTH (r = 0.387, p < 0.05) but not with serum BAP or serum DPD. The B/ST ratio for the femoral neck correlated with serum DPD (r = 0.431, p < 0.05) and intact PTH (r = 0.449, p < 0.05) but not with serum BAP.

CONCLUSIONS

Our data suggest that quantitative bone scintigraphy is a sensitive and useful method for evaluating bone metabolism in hemodialysis patients. The B/ST ratio for the skull may reflect changes of bone metabolism in hemodialysis patients.

A Comparison of Bone Scans in Uremic Patients Treated with Intermittent Peritoneal Dialysis Or Hemodialysis

The aim of the study was a comparative analysis of bone scans in uremic patients treated with intermittent peritoneal dialysis (IPD) or hemodialysis (HD). Bone scintigraphy was performed using technetium Tc 99m etidronate (EHDP) in 28 uremics (age 46.0±13.5 years, x±SD) on IPD for 3.1±3.0 months and 28 uremics (age 43.5±11.6 years) on HD for 47.3±33.9 months. Serum c terminal parathormone (cPTH) exceeded 5.3±3.3 and 6.8±3.5 times the upper normal limit of 1.4 ng/mL in IPD and HD patients, respectively. Despite significant differences in dialysis treatment duration in IPD and HD patients, an increased Tc 99m EHDP uptake in bones was shown with similar frequency, when all the groups were compared. However, in the group of patients with serum cPTH exceeding four times the upper normal limit (n = 30) or in the age group less than 45 years old (n = 26), a greater marker uptake was observed in HD patients. Significant differences (p < 0.05) were shown in the cranial vault: 33% of HD patients (n = 18) with higher cPTH and 47% of those less than 45 years old (n = 15) revealed an increased marker uptake, whereas it was not observed in any IPD patient. When scans of HD patients dialyzed less than (n = 11) and more than (n = 17) 30 months were compared, a significantly higher appearance of increased marker uptake was shown in cranial vault (41% vs 0%, p < 0.02) and in sacral bone (82% vs 36%, p < 0.02) in patients with longer dialysis. The latter group of HD patients also showed an increased marker uptake in cranial vault compared to the entire group of PD patients (41% vs 7%, p < 0.01). Our studies suggest that bone scan changes, indicating secondary hyperparathyroidism, progress significantly with prolongation of dialysis treatment, especially in patients with higher cPTH levels of younger age.

Scintigraphy in the clinical evaluation of disorders of mineral and skeletal metabolism in renal failure

In patients with renal bone disease skeletal and extra-skeletal abnormalities can be visualised using conventional bone scintigraphy. Some of these abnormalities are associated with characteristic scintigraphic appearances, which are reviewed in detail, and the possible mechanisms involved are discussed. Specific imaging with iodine 123 serum amyloid P component and iodine 131 beta 2-microglobulin is also discussed in the diagnosis of beta 2-microglobulin amyloidosis specific to patients on dialysis. In the light of available evidence, it appears that bone scintigraphy plays, so far, a limited role in the clinical evaluation of skeletal and extra-skeletal abnormalities in chronic renal failure. The potential role of bone scintigraphy in identifying patients with aluminium-related bone disease needs to be investigated further, and in this respect special attention must be given to the problem of high soft-tissue activity associated with impaired renal function. Timing haemodialysis sessions before scintigraphic imaging deserves wider recognition as it reduces high soft-tissue activity, thereby allowing bone uptake to be assessed more accurately. Specific imaging of amyloidosis resulting from beta 2-microglobulin deposition is a promising technique, but the relative value of the two proposed radiopharmaceuticals needs further clarification.

Bone scanning and photon absorptiometry in metabolic bone disease

Bone scan imaging with the current bone-seeking radiopharmaceuticals, the technetium-99m labelled diphosphonates, provides a functional display of skeletal metabolism and has dramatically improved our ability to investigate skeletal pathology. While the role of bone scanning in metastatic disease was recognized early, and welcomed by oncologists and other specialists alike, in the field of metabolic bone disease the realization of its potential value has been slower, with perhaps more reluctant acceptance. Nevertheless, the skeleton remains an extremely difficult organ to investigate, and a familiarity with bone scanning should be an essential part of the investigational armamentarium for anyone with an interest in the metabolic bone disorders. The measurement of bone mineral by photon absorptiometry is a relatively new technique, which is rapidly gaining acceptance. The ability to accurately detect and quantify changes in bone mass is potentially of considerable value in the diagnosis and management of osteoporosis. The technique provides us with an extremely important and powerful research tool but, at the present time, its role in clinical practice has yet to be established.

Observations on computerized quantitative bone scintigraphy in renal osteodystrophy

Skeletal radiotracer (99mTc-HEDP) uptake was quantitated with and without the aid of a computer in 30 chronic dialysis patients with histologic evidence of renal osteodystrophy. Before scintigraphy, elevated soft-tissue activity due to the absence of renal radiotracer excretion was reduced by hemodialysis. The results were compared with those of a normal group and with the results of the biochemical and the bone morphometric studies of these patients. In all patients the radiotracer uptake was elevated, often markedly. In several patients with minimal histologic bone disease, however, soft-tissue activity could not be normalized by hemodialysis although its influence on the quantitative data could be further reduced (but not excluded) by computer evaluation of skeletal radiotracer uptake. Since the latter technique clearly distinguished the majority of the patients from the normals, it appears that computerized quantitative skeletal analysis is a potentially accurate scintigraphic method for detecting renal osteodystrophy. The significant relationship between skeletal radiotracer uptake, in particular at the bone biopsy site, and only the histologic features of increased bone turnover suggest that hyperparathyroidism is the major cause of this increased tracer uptake in renal osteodystrophy.

Bone scintigraphy in the diagnosis and management of traumatic injury

Imaging with bone-seeking nuclear medicine radiopharmaceuticals has changed dramatically in a span of 10 years. The only indication for bone scintigraphy a decade ago was to detect skeletal metastases in patients with known carcinoma. Improvements in equipment and radiopharmaceuticals have led to the use of nuclear medicine studies for the detection and evaluation of a multitude of benign abnormalities. This article discusses the use of bone-seeking radiopharmaceuticals in traumatic processes involving the skeletal system, connective tissues, and muscles. A review of the subject is included, as well as some new ideas regarding the interpretation and evaluation of scintigraphs with respect to trauma to the bones and soft tissues.

Increased bone radiotracer uptake in renal osteodystrophy. Clinical evidence of hyperparathyroidism as the major cause

Bone radiotracer uptake in renal osteodystrophy was investigated in 35 dialysis patients by correlating the results of quantitative bone scintigraphy with those of biochemical and bone morphometric studies. There were highly significant correlations (P less than 0.001) between the total skeletal activity and the biochemical (iPTH and alkaline phosphatase), and histologic parameters of hyperparathyroidism. These clinical results strongly suggest that increased bone turnover i.e. hyperparathyroidism, rather than osteomalacia is the major cause of increased skeletal uptake in renal osteodystrophy.

Diphosphonates in the evaluation of metabolic bone disease

The bone scan may be of value in the assessment of patients with metabolic bone disease. However the superiority of the bone scan when compared to radiology in conditions such as renal osteodystrophy, osteomalacia, primary hyperparathyroidism, and osteoporosis requires substantiation with the newer radiopharmaceuticals which have a higher affinity for bone. Two methods of quantitating skeletal uptake of tracer have been assessed to try to remove the subjective aspect of bone scan evaluation. Measurements of bone to soft tissue ratios have proved clinically disappointing, but 24 hour whole body retention of diphosphonate appears to provide a sensitive index of increased bone turnover.

Pulmonary calcification in hemodialyzed patients detected by technetium-99m diphosphonate scanning

Metastatic pulmonary calcification, a well-known complication in patients with chronic disease, has been demonstrated postmortem in patients with a negative chest X-ray. Recently, scintigrams with bone-seeking radionuclides have been used to detect such subclinical pulmonary calcium deposits. We describe 23 patients on maintenance hemodialysis with no evidence of pulmonary calcification on chest X-ray who were prospectively studied by lung scanning with a bone-seeking radionuclide and pulmonary function testing. Of the 23 patients, 14 (61%) had a positive technetium-99m diphosphonate (99mTc-DP) scan (group 1). These patients were on dialysis 38 +/- 5 months compared with 12 +/- 4 months in 9 patients with a negative scan (group 2) (P less than 0.01). Age, sex, blood pressure, hematocrit, serum calcium, phosphorous, bicarbonate, magnesium, and calcium X phosphorus product, as well as parathyroid hormone level did not differ between the two groups. Of 10 group-1 patients tested, 7 had abnormal pulmonary diffusion capacity compared with non in 5 group-2 patients tested (P = 0.014). Histologic examination of the lung in 1 group-1 patients who expired revealed calcification (amorphous on X-ray diffraction), whereas none was found in 1 group-2 patients autopsied. These observations suggest that in patients on maintenance hemodialysis, pulmonary scanning with 99mTc-DP is a sensitive method for detecting pulmonary metastatic calcification, which may be associated with an abnormality in pulmonary diffusion capacity.

A comparison of bone scanning and radiology in the evaluation of patients with metabolic bone disease

Bone scans and radiographs were evaluated in 80 patients with metabolic bone disease (27 with osteoporosis, 14 with primary hyperparathyroidism, 24 with renal osteodystrophy and 15 with osteomalacia). The bone scan did not suggest a metabolic bone disorder in any of 27 patients with histologically proven osteoporosis. In 22 (81%) patients radiographs were reported as showing osteoporosis. In 10 (70%) vertebral fractures were seen on X-ray while these were noted in 11 (41%) patients on the bone scan. Vertebral fractures were usually visualised on the bone scan when these had occurred less than one year previously. In primary hyperparathyroidism the bone scan was suggestive of a metabolic bone disorder in 7 of 14 (50%) patients, while radiographs were reported as showing evidence of hyperparathyroidism in three (21%) cases. The bone scan suggested the presence of a metabolic bone disorder in all 24 patients with renal osteodystrophy and 15 patients with osteomalacia while the correct diagnosis was obtained in 14 (58%) and nine (60%) of these patients on X-ray. It is concluded that the bone scan is the more sensitive investigation in patients with osteomalacia, primary hyperparathyroidism and renal osteodystrophy. For osteoporosis radiology is the investigation of choice but the bone scan may be of value in assessing the duration of vertebral collapse.

Quantitative sacroiliac joint scintigraphy. A critical assessment

With quantitative sacroiliac joint scintigraphy (QSS), sacroiliac joint-to-sacrum (SIS) ratios greater than or equal to 1.40 are abnormal for our method. High SIS ratios are associated with roentgenographically appreciated sacroiliitis and with early clinically evident sacroiliitis. Although highly sensitive, QSS abnormalities are not specific for inflammatory sacroiliac (SI) joint disease. High SIS ratios are also seen in rheumatoid arthritis, degenerative abnormalities of the lumbosacral spine, and metabolic bone disorder. Other disorders with roentgenographic SI joint abnormalities must be studied scintigraphically before QSS can be employed as a useful diagnostic test.

Semi-quantitative interpretation of the bone scan in metabolic bone disease: definition and validation of the metabolic index

Certain easily recognisable features are commonly seen in the bone scans of patients with metabolic bone disorders. Seven such features have been numerically graded by three independent observers in the scans of 100 patients with metabolic bone disease and of 50 control subjects. The total score for each patient is defined as the metabolic index. The mean metabolic index for each group of patients with metabolic bone disease is significantly greater than that for the control group (P less than 0.001).

Joint effusions after kidney transplantation

Thirty-seven consecutive renal transplant recipients were studied prospectively for joint disease. Six developed arthralgias while corticosteroid doses were being lowered. Eleven patients (30%) developed knee effusions at a mean interval of 10 days following transplantation. Synovial fluids were colorless or very pale yellow, with few leukocytes (mean, 28/mm3). These benign transudative effusions did not correlate with immunologic abnormalities, transplant rejection, crystal deposition, or avascular necrosis and may have been due to high dose oral corticosteroid therapy.

Unusual bone images in hyperparathyroidism

Whole-body scans with 99Tcm-Sn polyphosphate were performed on four patients suffering from hyperparathyroidism. Two of the patients were investigated twice, at intervals of five and eight months. A variety of unusual but symmetrical images were obtained, not always confined to the skeleton. It is suggested that in conditions of renal failure the radiopharmaceutical may be avidly accumulated on first passage by calcifying areas in the soft tissues. Deteriorating blood supply to the bones reduces uptake of 99Tcm in the the skeleton.