The pitfalls of planar three-phase bone scintigraphy in nontraumatic hip avascular osteonecrosis.

PURPOSE: This study documented the previously reported lower sensitivity of routine planar three-phase bone scintigraphy (BS) performed using a high-resolution parallel-hole collimator compared with MRI to diagnose nontraumatic avascular necrosis of the hip (AVN). METHODS: Six observers reviewed 143 bone scintigrams obtained in patients with nontraumatic hip pain (n = 120) or a control group (n = 23). All patients had a standard radiograph and MRI within 2 months of the BS. Of 280 hips, 148 (53%) were painful on the day of the examination. The osteonecrosis group (AVN) consisted of 93 instances of AVN in 58 patients. Although it departs from the clinical situation, this method evaluated the intrinsic performance of the imaging method. The data were analyzed using a receiver operating characteristic method. RESULTS: For the six observers, the A(z) values were 0.65, 0.67, 0.66, 0.67, 0.73, and 0.79, respectively, and 0.66, 0.71, 0.75, 0.81, 0.81, 0.82, and 0.84 after removing hip diseases other than AVN through data manipulation. Bone marrow edema, as seen on MRI, was the most frequently reported misleading sign in false-positive diagnoses, especially in the early or late phases of the disease. False-negative diagnoses misclassified the scans as "asymptomatic hips" in 28 of 30 cases. Twenty-two of 30 scans appeared normal, but these AVN lesions were small (<25%) and were discovered by chance on MRIs that displayed bilateral involvement associated with radiographic evidence (stage 0 or 1). Thirteen of 20 patients were followed for 3 or more years, and only one worsened. CONCLUSIONS: BS is not indicated to diagnose possible contralateral AVN if the hip is asymptomatic. This study emphasizes the results from the literature; if indicated, a radionuclide hip investigation requires the use of a pin-hole collimator, a SPECT study with scatter correction and iterative reconstruction algorithms, or both.     

The usefulness of 99mTc sulfur colloid bone marrow scintigraphy combined with 111In leucocyte scintigraphy in prosthetic joint infection

AIM: To assess the extent to which bone marrow scintigraphy (BMS) makes the interpretation of leucocyte scintigraphy (LS) easier and improves its diagnostic value. METHODS: Seventy-three 111In LSs, 99mTc hydroxymethylene diphosphonate bone scintigraphies (BSs) and 99mTc sulfur colloid BMSs were performed in 60 patients with suspected infection related to a hip prosthesis or knee prosthesis, either in situ (+group, n = 43) or after removal for septic loosening (-group, n = 30). Bacteriological samples were obtained from all patients. LS was interpreted together with BS (LS-BS) or with BMS (LS-BMS) by three independent readers. RESULTS: The concordance among readers, estimated by the kappa test, was average with LS-BS (kappa/kappam coefficients = 0.58, 0.58 and 0.46, respectively, for the three pairs of readers) and excellent with LS-BMS (kappa/kappam coefficients = 1.00 for the three pairs of readers). With LS-BS, 64/219 interpretations were equivocal whereas only one was equivocal with LS-BMS. Sensitivity, specificity and accuracy of LS-BMS were, respectively, 80%, 94% and 91% in the +group, and 33%, 100% and 93% in the -group. CONCLUSION: We conclude that (1) the interpretation of the results for LS-BMS is very easy, in contrast to LS-BS; (2) the diagnostic value of LS-BMS for detecting infected joint prostheses is good; and (3) additional data are needed to assess the accuracy of LS-BMS when the prosthesis has been removed.     

Correlation of MRI and histomorphological findings in bone marrow oedema syndrome of the hip

Bone marrow oedema syndrome (BMOS) of the hip includes severe hip joint pain, focal loss of radiodensity in radiographs, increased uptake in bone scintigrams and the pattern of bone marrow oedema in the femoral heads in MRI scans. In 15 patients (16 hip joints) we found the clinical and radiological signs of BMOS. On T1-weighted MRI images areas of low signal intensity could be observed in the head, neck and the intertrochanteric region of the femur in various extensions. These areas showed a significant increase in signal intensity on the T2-weighted images. Because pain was resistant to conservative therapy all these patients were treated by core decompression of the femoral head in a prospective study. Bone cores were evaluated histologically using undecalcified sections and quantitative microradiography. The existence of intramedullary oedema in exactly the regions exhibiting the MRI pattern of bone marrow oedema was verified histologically; however, bone and marrow changes similar to those of early avascular necrosis (AVN) were also visible. These findings support our assumption that BMOS might be a transitory initial phase of AVN. Therefore core decompression treatment for patients suffering pain from BMOS is recommended after excluding other diseases.     

The relation of bone marrow scintigraphy and unilateral bone marrow biopsy in malignant lymphoma

To assess the diagnostic role of bone marrow scintigraphy (BMS) for detecting bone marrow infiltration by malignant lymphomas, 47 patients, 14 with malignant Hodgkin's and 33 with non-Hodgkin's lymphoma underwent BMS with 99mTc-sulphur-colloid and also unilateral iliac crest bone marrow biopsy (BMB). BM involvement in BMB was observed in 11 of the 47 patients. Four of these patients also had BMS lesions. Eight patients had BMS lesions not detected by BMB. There was poor agreement between the two modalities (kappa=0.137). Considering BMB as the gold standard, sensitivity, specificity, positive predictive value, negative predictive value and accuracy of BMS were 36%, 77%, 33%, 80%, and 68% respectively. In conclusion, BMS has a high negative predictive value and may be used as a complementary screening test for lymphoma to assess the extent of BM involvement, especially if magnetic resonance imaging-guided biopsy or positron emission tomography studies are not available, as is the case in developing countries.     

Pitfalls of bone scintigraphy in suspected hip fractures

In a review of 2617 patients who were admitted with a suspected fractured neck of femur over a period of five years, 213 had normal or equivocal plain radiographs, and were subsequently investigated by bone scintigraphy. Normal scans were obtained in 127 (60%) cases. Of the remaining 86 cases, 82 (38%) were reported to show fractures of the proximal femur, three showed pubic ramus fractures, and one acetabular fracture was demonstrated. Review and follow-up has revealed eight false positive and two false negative scans. The various factors accounting for these errors are considered, and the clinical implications discussed. Careful analysis of accompanying plain radiographs is stressed when interpreting scintigrams.     

Usefulness of 111In labeled leukocytes scintigraphy combined with 99mTc phytate liver scintigraphy for diagnosis of hepatic abscess comparing with CT and US]

111In labelled leukocyte scintigraphy (ILLS) was performed in five patients with hepatic abscess. For the accurate diagnosis of hepatic abscess, ILLS was superimposed on 99mTc phytate liver scintigraphy. The results of ILLS were compared with CT and US findings. Four of five patients (80%) showed abnormal accumulations in the liver. The smallest abscess detected was 46 mm x 43 mm. CT scan showed rim enhancement, which was a specific finding for hepatic abscess, in three patients. It was rather difficult to diagnose hepatic abscess by US. In two cases without definite rim enhancement on CT, the abscesses were diagnosed as hot spots by ILLS. We conclude that ILLS combined with 99mTc liver scintigraphy is useful for the diagnosis of hepatic abscess.     

Bone marrow scintigraphy in Paget's disease of bone

Sixteen patients with 20 lesions of Paget's disease of bone were studied with bone marrow scintigraphy (colloid), bone tissue scintigraphy and radiography. Bone marrow scintigraphy showed normal or increased colloid uptake in 15 of 20 pagetic lesions, and decreased uptake in 4. Bone tissue scintigraphy showed increased metabolic activity in all lesions and was useful in detecting polyostotic disease as well as the extent of the lesions. Conventional radiography most often showed the typical appearance of Paget's disease, but the changes observed were sometimes difficult to differentiate from malignant disease. However, a preserved or increased reticuloendothelial function in the pagetic lesion contradicts metastatic disease as a differential diagnosis. Bone marrow scintigraphy with radiocolloid is a valuable method in the analysis of Paget's disease of bone.     

Transient bone marrow edema of the hip

Transient bone marrow edema of the hip is characterized by moderate homogeneous low MR signal intensity with ill-defined margins that involves at least a portion of the femoral head. Spin echo T1-weighted images are helpful to exclude other underlying diseases (tumor, infection, necrosis from systemic origin…), for which marrow edema is secondary or no epiphyseal in location. High-resolution fat-suppressed T2-weighted or proton density images allow evaluation of the articular cartilage, subchondral bone and subchondal marrow: if the articular cartilage is abnormal, the lesion is irreversible (arthrosis or necrosis); if the subchondral bone is focally interrupted and/or if the femoral is no longer spherical, the lesion is irreversible (necrosis); if a focal linear fluid collection is present under the subchondral bone, the lesion is irreversible (necrosis). Finally, subchondral changes may provide useful prognostic information: the absence of any abnormality other than marrow edema typically indicates that complete resolution is likely; the presence of a focal T2-weighted hypointense lesion immediately next to the subchondral bone suggests an irreversible lesion, especially if it is equal to or thicker than 4mm or the joint space. In some instances, prognosis cannot be reliably determined requiring the need for follow-up imaging.     

Three-phase bone scintigraphy pattern of loosening in uncemented hip prostheses

The three-phase bone scintigraphy pattern of loosening in uncemented hip prostheses (UHPs) has not previously been elucidated. We evaluated 28 patients with complicated UHPs who had undergone total hip arthroplasty a very long time previously (range 3–20 years, mean 8.4). All the patients were surgically reviewed: 26 UHPs were found to be loosened and two infected. Nine asymptomatic UHPs were taken as controls. The dynamic phase was invariably negative in both loosened and asymptomatic UHPs while markedly positive in the infected ones. The blood pool phase was positive to various degrees in 16 of the 26 loosened UHPs as well as in the infected UHPs, but was invariably negative in painless replacements. In the bone phase, areas of significantly (discrete to marked) increased uptake were observed in all the loosened prostheses as well as in two-thirds of the asymptomatic ones. However, the regions of the lesser trochanter and/or tip and/or shaft were involved exclusively in the case of the loosened UHPs, and diffuse periprosthetic uptake was found only with loosened or infected implants. Areas of slight methylene diphosphonate (MDP) uptake were found at every periprosthetic site and areas of discrete to marked MDP uptake were commonly found in the acetabulum and/or the greater trochanter with both loosened and painless prostheses and are thus considered to be nonspecific findings.     

The value of bone marrow scintigraphy using 99mTc monoclonal antigranulocyte antibodies in complement to bone scintigraphy in detecting bone metastases from primary breast cancer

This prospective study evaluates bone marrow scintigraphy (BMS) in detecting bone metastases from primary breast cancer when performed in complement to conventional bone scan (BS). Sixty women predominantly with low-stage disease underwent BS followed by BMS within 1-35 days using BW250/183 antigranulocyte antibodies. A receiver operating characteristic (ROC) analysis was performed to compare BS to BS+BMS on a patient-by-patient basis using a 'gold standard' composed of subsequent computed tomography, magnetic resonance imaging, X-ray or BS examinations and at least a 12 month follow-up. Metastases were present in eight out of 60 patients (13%). Specificity was improved by BS+BMS compared to BS alone (90%, 65%) as well as positive predictive value (62%, 27%), accuracy (87%, 72%), positive (10.4, 2.4) and negative (0.20, 0.00) likelihood ratios. Sensitivity (100%, 88%) and negative predictive value (100%, 97%) were similar for BMS+BS and BS alone. As a result of BMS, clinical management was modified in 15 patients (25%). In conclusion, BMS supplements BS by improving specificity, positive predictive value and accuracy in detecting breast cancer bone metastases. The ROC curves show improved specificity for BS+BMS at the same sensitivity compared to BS alone. Consequently, BMS may be useful in low-stage subjects with positive or equivocal BS for metastases.     

Bone marrow scintigraphy in multiple myeloma. A comparison with bone scintigraphy and skeletal radiology

The radiographic patterns of the skeleton of 73 patients affected by multiple myeloma (MM) were compared to the correspondent scintigraphic findings. Whole body scans were performed using 99m Tc-diphosphonates (bone scintigraphy), and 99m Tc-microcolloids (bone marrow scintigraphy). The results indicate that: a) radiography is more sensitive and accurate than scintigraphy in detecting typical myeloma-related bone lesions; b) bone scintigraphy is useful in detecting alterations in particular locations--i.e., sternum, ribs, scapulae, etc.--which are difficult to demonstrate by plain X-rays; moreover, the recovery of the fractures can be visualized; c) bone marrow scintigraphy is employed to demonstrate the presence of marrow expansion, of cold/hot spots, and relative marrow uptake, related to phagocytic activity. Since in adult men red marrow is confined to the epiphysis of long bones and to the spine, all the diseases affecting bone marrow cause medullary expansion/reduction, which are both easily detected by specific radiopharmaceuticals. The peripheral expansion is clearly documented especially in distal humeri and femora since marrow uptake is included, in healthy adults, in the axial and proximal appendicular skeleton. In spite of its yielding unique information, bone marrow scintigraphy remains an additional technique of bone scan, because of its low diagnostic accuracy.     

Correlation of bone scintigraphy and histological findings in medial tibial syndrome

OBJECTIVE: To correlate bone scintigraphy and histopathological findings in patients with medial tibial syndrome. METHODS: Twenty patients (32 limbs) with a clinical diagnosis of medial tibial syndrome had surgery. Bone scintigraphy before the operation was compared with the histological appearance of bone and periosteal specimens obtained at surgery. RESULTS: Delayed bone scintigraphy showed normal appearance in 11 limbs, characteristic diffuse tubular pattern uptake in 16 limbs, and focal uptake in five. Periosteal histology disclosed fibrous thickening as the most common finding associated with increased vascularity, occasionally with chronic inflammatory cell infiltration, haemosiderin, and acid mucopolysaccharide deposition. Loss of osteocytes was the main finding of bone histology associated with some enlargement of lacunae and lamellar structure disruption. A grading system was used to score normal and abnormal histological appearance. For analysis the findings were regrouped to provide tables using Fisher's exact test. There was no correlation between bone scintigraphy and the histology of bone and periosteum, but two interesting observations were noted. Those cases with periosteal thickening had mostly normal bone scan appearance (p = 0.0028). Those cases with low levels of osteocyte loss had mostly abnormal bone scintigraphy. CONCLUSION: Abnormal histological appearance of bone and periosteum is a feature of medial tibial syndrome. These histological findings show poor correlation with bone scintigraphy. The exact pathogenesis of this syndrome remains unclear.     

Correlation between bone marrow edema and collapse of the femoral head in steroid-induced osteonecrosis

OBJECTIVE: The purpose of this study was to clarify whether bone marrow edema is detectable on initial MR imaging of steroid-induced osteonecrosis of the femoral head. SUBJECTS AND METHODS: Forty-eight hips with osteonecrosis were examined consecutively with MR imaging and radiography. In a previously reported screening program, osteonecrosis was diagnosed on MR imaging when subchondral bands of abnormal signals were present. In the screening program, the MR images of 200 hips of 100 patients receiving high-dose steroid therapy were examined prospectively. Subchondral bands were detected in 48 hips at a mean of 14 weeks after the initiation of steroid therapy. RESULTS: On follow-up MR imaging of 47 hips (one hip excluded) bone marrow edema was initially observed in 13 hips after the onset of hip pain. MR imaging of the remaining 34 hips did not reveal bone marrow edema and the patients were all asymptomatic. MR imaging of 31 of the 34 hips continued to show subchondral bands and MR imaging of the other three hips indicated that the subchondral bands had disappeared. When bone marrow edema was detectable, abnormal findings on radiography were slight but 11 (85%) of the 13 hips progressed to advanced osteonecrosis. Bone marrow edema was highly correlated with the subsequent collapse of the femoral head (p<0.0001). CONCLUSION: Bone marrow edema was not present on initial MR imaging of osteonecrosis. Bone marrow edema should be considered a marker for potential progression to advanced osteonecrosis, and careful examinations for osteonecrosis are necessary when bone marrow edema is seen.     

99Tcm-HMPAO leucocyte scintigraphy in the diagnosis of bone infection

The utility of 99Tcm-HMPAO leucocytes has been studied in combination with 99Tcm-MDP bone scanning in the diagnosis of bone infection in a series of 50 patients with a clinical suspicion of bone infection. Thirty-three patients were referred to our Service from the Department of Orthopaedic Surgery (Group A) and seventeen from the Infectious Disease Unit (Group B). A total of 52 lesion sites were studied. The leucocyte and bone studies were performed within four days. The leucocyte scan was obtained at 30-60 min and 4-6 h after i.v. injection of 370 +/- 74 MBq of 99Tcm-HMPAO leucocytes. After confirming the scintigraphic findings, the results obtained were: Group A, 12 true positive, 21 true negative and 2 false positive; and in Group B, 5 true positive, 9 true negative and 4 false negative. The overall sensitivity was 80.9% with a specificity of 93.7%. Although the high bone marrow activity seen with 99Tcm-HMPAO leucocytes may reduce sensitivity, very good results were obtained in bone infection. The use of 99Tcm means great progress in the radiolabelling of white blood cells in terms of availability and better image quality. The combination of 99Tcm-HMPAO leucocytes and 99Tcm-MDP can be recommended as one of the most suitable methods for use in the diagnosis of bone infection, especially in patients with previous bone disease.