Can the three-phase bone scan differentiate osteomyelitis from metabolic or metastatic bone disease?

The three-phase bone scan has been reported of value in the diagnosis of osteomyelitis. The use of a radionuclide angiogram, an immediate postinjection "blood pool" image, and 2 to 3 hour delayed image have been useful in separating nonosseous inflammatory disease from osteomyelitis. However, dependence on increased blood flow and focal hyperemia for this diagnosis may limit the use of the study if other processes are shown to produce similar results. To identify limitations of the three-phase bone scan we studied 14 patients with metastatic bone disease and nine patients with Paget's disease. Blood flow results showed no increase in three of 14 patients with metastases, intermediate increase in seven of 14 patients with metastases and two of nine patients with Paget's, and intense increase in four of 14 patients with metastases and seven of nine patients with Paget's. All patients showed increased focal activity in the immediate "blood pool" and delayed images. We conclude that because of increased flow Paget's disease may be difficult to separate from osteomyelitis. However, metastatic disease can often be differentiated on the basis of quantitative focal hyperemia. The three-phase bone scan remains of value in the diagnosis of osteomyelitis, but other diseases of bone must be included in the differential diagnosis.     

Is bone scintigraphy necessary in the initial surgical staging of chondrosarcoma of bone?

Objective  

To assess the value of whole-body bone scintigraphy in the initial surgical staging of chondrosarcoma of bone.     

Detection of bone metastases in thyroid cancer patients: bone scintigraphy or 18F-FDG PET?

BACKGROUND: Similar to the situation in other tumour types, it is currently unclear whether fluorodeoxyglucose (FDG) positron emission tomography (PET) is adequate in the detection of bone metastases of thyroid cancer. The purpose of this retrospective study was to evaluate the performance of bone scans in comparison with FDG PET in the detection of bone metastases in patients with differentiated thyroid cancer (DTC). MATERIALS AND METHODS: Twenty-four patients had undergone both FDG PET and bone scans within 6 months because of suspected bone metastases. All scans were re-evaluated using all available additional imaging and clinical data for verification. Scan findings were scored as positive, negative or doubtful. RESULTS: Bone metastases were present in eight of 24 (33%) patients. Only bone scintigraphy but not FDG PET suggested the presence of bone metastases in three patients, all confirmed with magnetic resonance imaging (MRI)/X-ray. Five patients were identified with bone metastases on both bone scan and FDG PET, which was confirmed by computed tomography (CT)/MRI/X-ray in four. Five patients had doubtful findings on bone scans whereas FDG PET scans were negative. MRI showed degenerative disorders in two of five and was normal in two. Eleven patients had both a negative bone scan and FDG PET scan. CONCLUSION: In three of eight (38%) thyroid cancer patients bone metastases were only identified on bone scans. Therefore, bone scans are still valuable in detecting bone metastases in patients with DTC and can not be replaced by FDG PET.     

Giant cell tumor of bone with secondary aneurysmal bone cyst-like change producing β-human chorionic gonadotropin

Giant cell tumor of bone is a benign, locally aggressive neoplasm that is composed of sheets of neoplastic mononuclear cells interspersed amongst non-neoplastic, uniformly distributed, osteoclast-like giant cells. They represent approximately 4–5 % of primary bone tumors. Rarely, bone tumors have been noted to produce human chorionic gonadotropin, a finding most often reported in osteosarcoma. We present the case of a young woman who presented with a low-level human chorionic gonadotropin level which, after resection of her recurrent giant cell tumor of bone with secondary aneurysmal bone cyst-like change, became undetectable in her blood. Furthermore, cells within the aneurysmal bone cyst component were immunohistochemically positive for β-human chorionic gonadotropin. This is the first report of such a finding in the literature.     

18F-FDG PET/CT bone/bone marrow findings in Hodgkin’s lymphoma may circumvent the use of bone marrow trephine biopsy at diagnosis staging

Purpose

Accurate staging of Hodgkin’s lymphoma (HL) is necessary in selecting appropriate treatment. Bone marrow trephine biopsy (BMB) is the standard procedure for depicting bone marrow involvement. BMB is invasive and explores a limited part of the bone marrow. ¹⁸F-FDG PET/CT is now widely used for assessing response to therapy in HL and a baseline study is obtained to improve accuracy. The aim of this retrospective analysis was to assess whether routine BMB remains necessary with concomitant ¹⁸F-FDG PET/CT.

Methods

Data from 83 patients (newly diagnosed HL) were reviewed. All patients had received contrast-enhanced CT, BMB and ¹⁸F-FDG PET/CT. Results of BMB were not available at the time of ¹⁸F-FDG PET/CT imaging.

Results

Seven patients had lymphomatous involvement on BMB. Four patients had bone involvement on conventional CT (two with negative BMB). All patients with bone marrow and/or bone lesions at conventional staging were also diagnosed on ¹⁸F-FDG PET/CT scan. PET/CT depicted FDG-avid bone/bone marrow foci in nine additional patients. Four of them had only one or two foci, while the other had multiple foci. However, the iliac crest, site of the BMB, was not involved on ¹⁸F-FDG PET/CT. Osteolytic/sclerotic lesions matching FDG-avid foci were visible on the CT part of PET/CT in three patients. MRI ordered in three other patients suggested bone marrow involvement. Interim and/or end-therapy ¹⁸F-FDG PET/CT documented response of FDG-avid bone/bone marrow foci to chemotherapy in every patient.

Conclusion

¹⁸F-FDG PET/CT highly improves sensitivity for diagnosis of bone/bone marrow lesions in HL compared to conventional staging.     

Tensile properties of an anterior cruciate ligament graft after bone–patellar tendon–bone press-fit fixation

Hardware used for fixation of ACL autografts in bone tunnels frequently complicates revision surgery, requiring two-stage procedures when a bone-patellar tendon-bone (B-PT-B) autograft is used for ACL reconstruction. Therefore alternative procedures that eliminate hardware have been advocated. This study compared the mechanical behavior of two fixation procedures: a widely used interference screw (IFS) fixation and a press-fit fixation that is hardware free. Twenty hind limbs from skeletally mature Saanen breed goats were used in this study, ten each in IFS and press-fit groups. After ACL reconstruction the specimens were dissected, leaving a femur-ACL graft-tibia complex (FATC) for uniaxial tensile testing. The tests included a series of three cyclic creep tests (C1-C3) for the evaluation of residual elongation followed by a tensile load to failure test to obtain linear stiffness and ultimate load of the FATCs. Four of ten specimens failed during the cyclic creep test for the press-fit group, compared to one for the IFS group. For the remaining specimens residual elongation following three cyclic creep tests (C1-C3) was 1.7+/-0.5 mm in the press-fit group compared to 1.3+/-0.6 mm in the IFS group, and there was no statistical significant difference between the two fixations. In the load to failure test there was also no statistical significant difference in linear stiffness between the two fixations. However, the ultimate load for the press-fit group (215+/-75 N) was significantly lower than that for the IFS group (328+/-103 N). These results provide the basis for future studies involving the time course of healing of these two procedures using the goat model.     

Anatomic double-bundle ACL reconstruction using a bone–patellar tendon–bone autograft: a technical note

This article describes an original arthroscopic double-bundle anterior cruciate ligament (ACL) reconstruction technique using a bone–patellar tendon–bone autograft. A rectangular patellar bone block, with a double strand patellar tendon, and a double tibial bone block is harvested. The femoral anteromedial tunnel is made using an all-inside technique by the anteromedial portal. The femoral posterolateral (PL) tunnel is created with an outside-in technique, with a 30° divergence between both tunnels. A single tibial tunnel is drilled, the graft is then passed through the tibial tunnel, and the bundles are separately tensioned and fixed with three bioabsorbable interference screws. The femoral AM bone block is fixed by the anteromedial portal, the tibial bone block is then fixed in an oblique manner in order to mimic the ACL orientation with the knee at 30° of flexion. The femoral PL bone block is fixed at the end with the knee in full extension.     

The “sickle-sign” in bone scintigraphy

A side-effect of an intensive cytotoxic treatment on bone scanning will be reported: the socalled sickle sign, a diffuse activity arlund the calvarium seen only in patients at cytotoxic therapy. The differentiation between this harmless side-effect and abnormalities caused by the cancer could be done in our patients by a vertex view. All patients with skull metastases or meningeal carcinosis and this sign in the frontal and lateral view had an inhomogenous uptake in the vertex view. This view should therefore be added to the standard views in all patients with the sickle sign.     

Press-fit fixation in reconstruction of anterior cruciate ligament,using bone–patellar tendon–bone graft

We studied arthroscopic reconstruction of the anterior cruciate ligament (ACL) using patellar ligament-bone graft fixed to the femur by press-fit technique. The main feature of this technique was a stable bony fixation on the femoral site without using interference screws or other fixation devices. We treated 42 patients with ACL rupture by this technique; clinical examination was carried out preoperatively and at 3 months, 6 months, and then every 6 months using the standard criteria for evaluation of the IKDC (mean follow-up 29 months, 22–41). CT and MRI were performed 6 months postoperatively. According to IKDC score 37 knee (88%) were graded as normal or nearly normal, 4 (10%) as abnormal, and one (2%) as severely abnormal, none of the poor results was due to instability. Reconstruction of the ACL by press-fit technique is a more anatomically oriented method of fixation without the complications of interference screws at the femoral attachment of the graft.     

Sclerosing bone dysplasias — a target-site approach

Sclerosing bone dysplasias are a poorly understood group of developmental anomalies, much of whose etiology is still obscure. The list of conditions constituting this group is relatively short: osteopetrosis (Albers-Schönberg disease), pycnodysostosis (Maroteaux-Lamy disease), enostosis (bone island), osteopoikilosis, osteopathia striata (Voorhoeve disease), progressive diaphyseal dysplasia (Camurati-Engelmann disease), hereditary multiple diaphyseal sclerosis (Ribbing disease), four types of endosteal hyperostosis (van Buchem disease, Worth disease, Nakamura disease, and Truswell-Hansen disease), dysosteosclerosis, metaphyseal dysplasia (Pyle's disease), craniometaphyseal dysplasia, melorheostosis (Leri disease), and craniodiaphyseal dysplasia. There are instances in which two or more of the above disorders coexist. These are termed overlap syndromes, most commonly involving osteopathia striata, osteopoikilosis, and melorheostosis. A classification of these dysplasias is elaborated based on a target-site approach that views them as disturbances in development associated with the processes of either endochondral or intramembranous bone formation, or both. Accumulated evidence suggests that many of these disorders stem from common defects in bone resorption and/or formation during the processes of skeletal maturation and modeling. Finally, the subgroup of overlap syndromes is emphasized as indicating a strong interrelationship between the sclerosing dysplasias of bone, with perhaps a common pathogenesis for many.This article is one in a series of review articles which represent expansions of papers presented at the annual meeting of the International Skeletal Society and were solicited by the editors     

Does the trabecular bone structure depicted by high-resolution MRI of the calcaneus reflect the true bone structure?

RATIONALE AND OBJECTIVES: The purpose of this study was to compare trabecular bone structure parameters assessed with high-resolution magnetic resonance imaging (HR-MRI) with those determined in specimen sections. METHODS: High-resolution MR images were obtained for 30 calcaneus specimens with a three-dimensional, T1-weighted spin-echo sequence (spatial in-plane resolution 0.195 mm, slice thicknesses of 0.3 and 0.9 mm). Thirty-eight sections were obtained from the specimens, and contact radiography was performed. In the corresponding sections, structural parameters analogous to bone histomorphometry were determined. RESULTS: Significant correlations between MRI-derived structural parameters and those derived from macro pathological sections were found: r values of up to 0.75 were obtained (P < 0.01). The highest correlations were found for apparent bone volume/total volume and trabecular thickness. Image thresholding techniques showed a significant impact on these correlations (P < 0.01). The thinner MR sections were less susceptible to the different thresholding algorithms. CONCLUSIONS: Trabecular bone structure depicted by HR-MR images is significantly correlated with that shown in macro sections (P < 0.01); however, a number of limitations have to be considered, including the substantial impact of thresholding techniques and slice thickness.     

Dynamic contrast-enhanced MRI in Paget’s disease of bone–correlation of regional microcirculation and bone turnover

The purpose of this study was to evaluate regional microcirculation in Paget’s disease of bone (PD) with dynamic contrast-enhanced MR imaging (DCE-MRI). Additionally, we correlated regional bone perfusion with alkaline phosphatase as serum marker of bone turnover. We examined 71 patients with PD (27 men, 44 women, 67±10 years) localized at the axial and appendicular skeleton. Contrast uptake was analyzed using a two-compartment model with the output variables amplitude A and exchange rate constant k_ep. Color-coded parametric images were generated to visualize microcirculation. Serum levels of alkaline phosphatase (AP) were compared with DCE-MRI parameters. Amplitude A and exchange rate constant k_ep were significantly increased in PD compared to unaffected bone (A_PD 0.81±0.24 vs. A_control 0.34±0.1 and k_{ep PD} 4.0±2.86 vs. k_{ep control} 1.73±0.88, p<0.001). There was a significant correlation (r_s=0.5–0.7) of DCE-MRI parameters and AP at the axial (pelvis, spine) and appendicular skeleton (femur, tibia). The long bones showed increased circulation of the advancing peripheral zones and no vascularization of the central part, which had been replaced by fatty tissue. Regional microcirculation in PD is inhomogeneous with focal areas of excessive hypervascularity, especially in the advancing peripheral zone. There is a significant correlation of bone circulation and bone turnover in PD. DCE-MRI might therefore be a diagnostic tool for monitoring therapeutic effects of bisphoshonates in Paget’s disease of bone.     

Scintigraphic changes in bone metastasis from prostate cancer after hormonal therapy—Comparison with tumor markers and bone X-ray

Bone scintigraphy is often performed to assess the response to systemic therapy of bone metastasis from prostate cancer. We examined the changes in bone scintigraphic findings and the agreement with AIP, AcP, or other tumor markers measured in the follow-up of patients with known bone metastasis after hormonal therapy. Out of 32 patients, 22 (69%) showed improved scintigraphic findings on the first follow-up bone scintigraphy after hormonal therapy. However, 7 out of 22 patients who showed improvement on the first follow-up scintigraphy, deteriorated thereafter. Changes in the scintigraphic findings were closely correlated with those in the measured tumor markers except for patients with small bone metastasis. Though there were no significant differences in the agreement ratios of the 6 tumor markers evaluated, AIP might be a practical and acceptable indicator. Bone X-ray findings did not change at all in almost half of the cases though the scintigraphic findings showed improvement or deterioration.     

Transient osteoporosis: transient bone marrow edema?

Ten patients with debilitating hip or knee pain were examined with magnetic resonance (MR) imaging. All had conventional radiographs that were either normal or showed nonspecific osteopenia. Nine patients had bone scintigrams that showed focal increased radionuclide uptake in the region of the painful joint. In each case, MR images of the affected joint showed regional decreased signal intensity of the bone marrow on T1-weighted images and increased signal intensity on T2-weighted images. Biopsy results of four patients excluded ischemic necrosis and metastases. The symptoms resolved spontaneously in all cases. The ten patients were followed up for 12-36 months, and there were no recurrences. The authors believe that the findings on MR images represent a transient increase in bone marrow water content. The focal findings on scintigrams confirmed the periarticular distribution of the process and provided evidence of accompanying hyperemia and increased bone mineral metabolism. For lack of a better term and to emphasize the generic character of the condition, the authors termed this condition "the transient marrow edema syndrome."     

Kimura’s disease involving a long bone

Kimura’s disease is a rare, benign lymphoproliferative disorder of unknown etiology. It occurs most often in Asian men, usually in the second or third decade of life. Most lesions occur in the head and neck followed by the axilla, groin, popliteal region, and arm. The lesions are commonly found in soft tissues. To the best of our knowledge, there has been only one case report of bone involvement in Kimura’s disease presented on plain radiography. We report a case of Kimura’s disease that involved the proximal meta-diaphysis of the humerus and adjacent soft tissue shown on radiography and MR imaging.     

Precision of bone densitometry measurements: when is change true change and does it vary across bone density values?

The precision error of the bone densitometer is used to interpret significant change in bone mineral density (BMD) in serial studies. The precision error can be expressed as standard deviation (SD) or coefficient of variation (CV). The aims of this study are to determine the precision error over a range of BMD values and to demonstrate the application of the precision error in clinical practice. A bone phantom was used consisting of a perspex block with eight compartments containing varying amounts of hydroxyapatite powder to simulate a range of bone densities. The block was scanned 21 times and manual regions placed over each compartment to measure the BMD in each compartment. There were no significant differences in the variances or SD for all eight compartments, that is, over the range of BMD normally encountered in clinical practice. However, the calculated CV show a progressive fall in values as the BMD rises. Therefore, the SD should be used to calculate significant BMD change. In a practise with quality control procedures in place to detect calibration drift and with appropriately trained personnel, a change of approximately 0.05 g/cm2 is generally regarded as being a significant change at a 95% confidence level.     

Biomechanical evaluation of a new cross-pin technique for the fixation of different sized bone–patellar tendon–bone grafts

To overcome the disadvantages of interference-screw fixation of bone–patellar tendon–bone (BPTB) grafts, new fixation techniques for anterior cruciate ligament (ACL) grafts using biodegradable pins have been developed. The hypothesis of the present study was that cross-pin fixation techniques provide a primary stability that is comparable to that of interference screws. A biomechanical in vitro study was discussed. Human BPTB grafts of 8, 9 and 10 mm diameter were fixed in bovine knees with biodegradable cross pins (diameter: 2.0, 2.7 or 3.2 mm) or biodegradable interference screws. Stiffness and ultimate load were evaluated. For 9 and 10 mm BPTB grafts, no statistically significant difference in maximum load and stiffness was found between the four fixation techniques tested. For 8 mm bone blocks the maximum load of the 3.2 mm pins (274.2 N) was significantly lower than for the 2.0 mm pins (479.8 N) and the interference screws (504.0 N). Predominant failure mode in this group was bone-block fracture. Thicker grafts (9 and 10 mm) fixed with the 2.0 mm pins predominantly failed by implant fracture. Femoral fixation of 8, 9 and 10 mm BPTB grafts using cross pins leads to biomechanical properties that are comparable to biodegradable interference screws when tested by a single-cycle load to failure. Cross pins provide a rigid fixation for 9 and 10 mm BPTB grafts.     

Diagnosis of bone metastasis with whole body MRI?

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