Radionuclide imaging in the diagnosis and management of orthopaedic disease

Nuclear medicine imaging is often used in the diagnosis and management of several orthopaedic conditions. Bone scintigraphy measures gamma ray emission to detect the distribution of an injected radiolabeled tracer on multiple image projections. In general, this imaging modality has relatively high sensitivity but low specificity in the diagnosis of occult fractures, bone tumors, metabolic bone disease, and infection. Positron emission tomography measures tissue metabolism and perfusion by detecting short half-life positron ray emission of an injected radiopharmaceutical tracer. Historically, positron emission tomography has been used only to monitor bone metastasis and aid in the diagnosis of osteomyelitis; however, this technology has recently been applied to other orthopaedic conditions for which current imaging modalities are insufficient.     

Nuclear medicine techniques in the diagnosis of orthopaedic diseases

Nuclear medicine techniques show metabolic processes, allowing the diagnoses of many bone and joint disorders. For most orthopaedic indications three-phase bone scintigraphy is used, showing inflammatory bone and joint diseases, traumatic and post-operative disorders as well as necrotic or malignant changes. In addition to bone scintigraphy, there are radiopharmaceuticals to depict inflammatory processes. Finally, positron emission tomography is a modern imaging technique used mainly for tumor diagnostics, but also for detection of inflammation.     

Nuklearmedizinische Diagnostik bei orthopädischen Erkrankungen

Nuclear medicine techniques show metabolic processes, allowing the diagnoses of many bone and joint disorders. For most orthopaedic indications three-phase bone scintigraphy is used, showing inflammatory bone and joint diseases, traumatic and post-operative disorders as well as necrotic or malignant changes. In addition to bone scintigraphy, there are radiopharmaceuticals to depict inflammatory processes. Finally, positron emission tomography is a modern imaging technique used mainly for tumor diagnostics, but also for detection of inflammation.     

Diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer: Current practice

Nuclear medicine techniques continue to be important non-invasive imaging tools assisting the diagnosis, monitoring and--in some cases--treatment of prostate cancer. Bone scintigraphy was the premier modality to have an extensive role in the staging of prostate cancer and has remained an integral tool for over three decades in the assessment of newly diagnosed disease or in follow-up staging. Therapeutic treatment and palliation of disseminated disease, particularly in the skeleton, has also been successful with several radioisotopes including strontium-89 chloride. Despite advances in nuclear medicine techniques and molecular imaging technology such as positron emission tomography and radioimmunoscintigraphy, bone scintigraphy still remains the gold standard in the assessment of osseous metastatic disease in prostate cancer. Thus, it is important to continually review the modalities that have remained important over time and not just to focus on newer technologies. This article summarizes the current diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer with particular reference to radionuclide bone scintigraphy and positron emission tomography.     

Konservative und operative Therapie der Klavikulaschaftfrakturen

The imaging diagnostics of osteomyelitis contain a combination of radiological and nuclear medicine procedures. The conventional radiographic image as first choice examination shows structural changes of the bone and also can give information about localization and enlargement of an osseous infection. Positron emission tomography/computed tomography (PET/CT) is the most sensitive verification procedure. It allows a reliable verification of extent and localization of the bone infection, the proof of satellite foci and soft tissue infections as well as the differential diagnostic distinction from a neoplasia. However, PET/CT scans in the diagnostic workup of osteomyelitis are reserved for special issues due to the high examination costs and the usually limited availability. In cases of negative fluorodeoxyglucose (FDG) PET findings, a chronic osteomyelitis is almost ruled out. In daily practice further diagnostic procedures include besides clinical and laboratory findings imaging by CT and magnetic resonance imaging (MRI). If these procedures do not provide verified results, bone scintigraphy can lead to the final diagnosis.     

Role of radionuclide imaging in the orthopedic patient

Since its introduction more than 40 years ago, nuclear medicine has played an important role in the diagnosis and detection of soft tissue and skeletal disorders. Skeletal scintigraphy or bone scanning is a diagnostic study used to evaluate the distribution of osteoblastic activity or active bone formation within the body. Because no single imaging technique is ideal in all clinical situations, selecting an appropriate imaging test depends on understanding the pathophysiology of the suspected condition and limitations of each technique. This article provides a brief overview of bone scintigraphy, infection imaging, and positron emission tomography in the context of current, adult orthopedic practice.     

Szintigraphie/Positronenemissionstomographie

Skeletal scintigraphy and fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) are established nuclear medicine modalities in the diagnosis of soft tissue tumors. Skeletal scintigraphy scans are performed for detection of osseous infiltration by the primary tumor, of bone metastases and planning of magnetic resonance imaging (MRI). The PET/CT technique has a great potential for assessing tumor grade, for accurate N and M staging, treatment monitoring and in biopsy planning. Recurrent tumors can be detected with high sensitivity, particularly if conventional imaging is impaired by metallic implants. According to current guidelines, if a malignant soft tissue tumor is suspected or proven, PET/CT and PET/MRT should be considered even in children and adolescents.     

Osteoid osteoma of the inferior articular process of L5 associated with a bilateral spondylosis: a case report

We report the case of an 8-year-old boy who presented an osteoid osteoma of L5 associated with bilateral spondylolysis involving the same vertebra. Diagnostic bone scintigraphy is highly contributive in children presenting back pain. For us, it is the first intention exploration in patients with isthmic lysis seen on the plain x-ray. Symptomatic spondylolysis is the most frequent cause of back pain in children and is much more frequent than vertebral osteoid osteoma. The presence of isthmic lysis associated with focal uptake on the bone scintigraphy is highly suggestive of symptomatic spondylolysis. In this context, magnetic resonance imaging should be performed for both diagnostic purposes and prognostic assessment. The degree of bone and soft tissue edema in the present case was unusual for symptomatic spondylolysis. Complementary computed tomography finally established the diagnosis of osteoid osteoma of the posterior vertebral arch. To our knowledge, the association of osteoid osteoma with bilateral spondylolysis on the same vertebra has not been described elsewhere. In children, the diagnosis of symptomatic spondylolysis can only be established after ruling out other causes of back pain. The diagnosis of osteoid osteoma must be kept in mind.     

The accuracy of diagnostic imaging for the assessment of chronic osteomyelitis: a systematic review and meta-analysis

BACKGROUND: A variety of diagnostic imaging techniques is available for excluding or confirming chronic osteomyelitis. Until now, an evidence-based algorithmic model for choosing the most suitable imaging technique has been lacking. The objective of this study was to determine the accuracy of current imaging modalities in the diagnosis of chronic osteomyelitis. METHODS: A systematic review and meta-analysis of the literature was conducted with a comprehensive search of the MEDLINE, EMBASE, and Current Contents databases to identify clinical studies on chronic osteomyelitis that evaluated diagnostic imaging modalities. The value of each imaging technique was studied by determining its sensitivity and specificity compared with the results of histological analysis, findings on culture, and clinical follow-up of more than six months. RESULTS: A total of twenty-three clinical studies in which the accuracy was described for radiography (two studies), magnetic resonance imaging (five), computed tomography (one), bone scintigraphy (seven), leukocyte scintigraphy (thirteen), gallium scintigraphy (one), combined bone and leukocyte scintigraphy (six), combined bone and gallium scintigraphy (three), and fluorodeoxyglucose positron emission tomography (four) were included in the review. No meta-analysis was performed with respect to computed tomography, gallium scintigraphy, and radiography. Pooled sensitivity demonstrated that fluorodeoxyglucose positron emission tomography was the most sensitive technique, with a sensitivity of 96% (95% confidence interval, 88% to 99%) compared with 82% (95% confidence interval, 70% to 89%) for bone scintigraphy, 61% (95% confidence interval, 43% to 76%) for leukocyte scintigraphy, 78% (95% confidence interval, 72% to 83%) for combined bone and leukocyte scintigraphy, and 84% (95% confidence interval, 69% to 92%) for magnetic resonance imaging. Pooled specificity demonstrated that bone scintigraphy had the lowest specificity, with a specificity of 25% (95% confidence interval, 16% to 36%) compared with 60% (95% confidence interval, 38% to 78%) for magnetic resonance imaging, 77% (95% confidence interval, 63% to 87%) for leukocyte scintigraphy, 84% (95% confidence interval, 75% to 90%) for combined bone and leukocyte scintigraphy, and 91% (95% confidence interval, 81% to 95%) for fluorodeoxyglucose positron emission tomography. The sensitivity of leukocyte scintigraphy in detecting chronic osteomyelitis in the peripheral skeleton was 84% (95% confidence interval, 72% to 91%) compared with 21% (95% confidence interval, 11% to 38%) for its detection of chronic osteomyelitis in the axial skeleton. The specificity of leukocyte scintigraphy in the axial skeleton was 60% (95% confidence interval, 39% to 78%) compared with 80% (95% confidence interval, 61% to 91%) for the peripheral skeleton. CONCLUSIONS: Fluorodeoxyglucose positron emission tomography has the highest diagnostic accuracy for confirming or excluding the diagnosis of chronic osteomyelitis. Leukocyte scintigraphy has an appropriate diagnostic accuracy in the peripheral skeleton, but fluorodeoxyglucose positron emission tomography is superior for detecting chronic osteomyelitis in the axial skeleton.     

核医学影像技术在淋巴瘤诊疗中的应用

近年来,功能性显像技术在淋巴瘤诊疗中逐渐占据重要地位。用于淋巴瘤诊疗的核医学影像技术主要包括单光子发射型断层扫描技术（SPECT）、正电子发射型断层显像（PET）、正电子发射型断层/计算机体层摄影术（PET/CT）。67Ga-枸橼酸较早用于诊断淋巴瘤的功能性显像,后逐渐被18F-FDG取代。PET/CT的应用实现了功能影像与解剖影像有机结合及优势互补,对淋巴瘤的定位、定性及分期更准确,在淋巴瘤的诊疗方面显示出重要的临床应用价值。本文对18F-FDG PET及PET/CT在淋巴瘤诊疗方面的应用现状进行综述。     

Bild gebende Verfahren in der Unfallchirurgie – Konsensuskonferenz

The objective of the consensus conference was to summarize the current state of the art of indications for diagnostic imaging studies in trauma surgery of the hand, knee, and foot and ankle. Conventional roentgenograms still have a high value in diagnosis, while conventional tomography and stress radiography have been abandoned in favour of computed tomography (CT) and magnetic resonance imaging (MRI). Spiral CT (SCT) and its further development multislice- CT (MSCT) allow high-resolution representations of bony structures in all three spatial planes. The application of CT for preoperative planning, navigation and postoperative therapy monitoring should be emphasized. MRT is particularly well suited to sensitive detection of occult fractures, diagnosis of lesions of the internal structures of the joints, such as cartilage, ligaments and menisci. Indications for soft tissue sonography are tendinous lesions, while bone scintigraphy is now only recommended as an option when reflex dystrophy is present. The application of imaging techniques according to algorithms allows efficient and cost-effective diagnosis by imaging techniques governed by objective and reproducible criteria.     

骨转移瘤的误诊分析

目的 提高对骨转移瘤的认识，降低骨转移瘤的误诊率。方法 通过对骨转移瘤的发生机制、发病率、好发部位、骨转移瘤来自非骨原发肿瘤的顺序、监床表现与诊断方法等的认识，并对临床工作中5例被误诊为骨转移瘤病例长期随访结果进行分析。结果 5例均获得远期随访，24～96个月（平均57.6个月），患者生活良好。例1、2为肺癌与前列腺癌，未见肿瘤复发与骨转移。例4、5为脊柱结核，病情稳定，病灶修复。例3为L3S1椎间盘炎。分析误诊的原因为读片未能很好地结合临床全面考虑；对先进影像检查所见缺乏经验，认识不足。结论 大多数骨转移瘤通过详细分析病史、临床表现及影像学检查可以明确诊断。X线检查、核素全身骨扫描、CT、MR等先进诊断技术对诊断骨转移瘤有重要作用。先进的影像检查技术敏感性强，特异性较差，但仍可从中找出诊断的规律，相互补充，提高诊断正确率。此外，新的核素鹰眼系统及MR弥散加权像可提高对老年良性（如骨质疏松）与恶性（如骨转移瘤）椎体压缩性骨折的鉴别诊断。     

What is the future of patient-specific vertebral fracture prediction?

This paper aims to introduce a few alternative methodologies for prediction of vertebral fractures, the most common type being fragility fracture in the elderly. Current methods, such as DXA, for diagnosing osteoporosis and predicting the risk of vertebral failure, are often not accurate thereby preventing those patients at risk from receiving adequate treatment. Robust fracture prediction models for vertebral fracture risk should not only include BMD, as measured by DXA, but should incorporate a wide range of factors including bone geometry, bone mineral distribution within the vertebral body, daily living activities, and spine musculature. One promising technique is finite element modeling, which has been developed over the past several decades and implements clinical imaging, such as quantitative computed tomography (QCT), and engineering fundamentals to more accurately predict the risk of fracture. Other imaging tools that assess bone mineral distribution and structure at the microscopic level include micro-CT or high-resolution peripheral QCT (HR-pQCT). These newer techniques hold the promise of more accurate diagnosis of osteoporosis and those at risk for vertebral insufficiency fractures before they occur.     

Current considerations in the management of neoplastic spinal cord compression

Nearly 20% of patients with neoplastic involvement of the vertebral column develop spinal cord compression, and in 8% this is the initial manifestation of cancer. Important determinants of functional prognosis are: 1) tumor biology, 2) pretreatment neurologic status, and 3) tumor location within the spinal canal and the therapy employed. Future efforts should be invested in manipulation of the last two determinants. Delay in neurologic deterioration may be achieved by pharmacologic manipulation of the deleterious pathophysiologic processes operating in the compressed spinal cord, as recently demonstrated in experimental animal models. Use of modern neuro-imaging techniques (metrizamide myelography combined with computed tomography, and/or magnetic resonance imaging) will accurately define tumor extent and location. Radiotherapy is indicated in highly or moderately radiosensitive tumors. Surgery is reserved for the following situations: diagnosis in doubt, previous radiation exposure, radioresistant tumors, neurologic deterioration during irradiation, and the presence of spinal instability or bone compression of the neural structures. The location of the compressing tumor will dictate the surgical approach--a vertebral body resection in an anterior or anterolateral tumor and a laminectomy in a posterior or posterolateral deposit. Modern instrumentation techniques for spinal column stabilization or vertebral body replacement will allow immediate painless ambulation and a better quality of life for these patients.     

Nuclear imaging in the diagnosis of the infected total joint arthroplasty

Nuclear medicine can be of great value in diagnosing infected total joint arthroplasties. Bone scintigraphy is very sensitive for the diagnosis of prosthetic infection but is nonspecific. Gallium scintigraphy has been used in conjunction with bone scintigraphy, but this approach has not proven to be as valuable as originally anticipated. Indium leukocyte scintigraphy, especially when correlated with a bone scan and, at times, a bone marrow scan, is now the preferred scintigraphic approach for identifying the infected prosthesis. Newer imaging agents such as technetium leukocytes and radiolabeled antibodies are now being studied to determine their role in the management of prosthetic infection.     

Aktuelle bildgebende Diagnostik der Wirbelsäulenerkrankungen

Imaging of the spine is an essential prerequisite in the clinical workup of spine disease. Conventional radiography (CR) is still used as a basic diagnostic tool and enables an initial diagnosis to clarify symptomatology. Advanced cross-sectional techniques such as magnetic resonance imaging and computed tomography enable a dedicated diagnostic workup only of complex spinal pathologies. Due to its enormous innovation and broad availability, multidetector computed tomography could replace spinal CR in the diagnostic workup of acute and multiply injured patients. Nuclear medicine bone scans and positron emission tomography serve as screening studies and are an adjunct to morphologic radiological imaging. This review article summarizes the radiological and nuclear medicine imaging modalities and their diagnostic and therapeutic significance for diagnostic workup of common spinal disorders.     

Wertigkeit der Schnittbildgebung bei posttraumatischem Low-Grade-Infekt

Regarding imaging diagnostics in case of posttraumatic or postoperative chronic osteomyelitis, x-ray should be the first choice to obtain basic information of the affected bone. Because knowledge of the exact dimensions of the inflammatory changes is essential for adequate therapy planning, diagnostics via cross-sectional imaging is indicated in most cases. In order to adequately estimate the lesion’s dimensions, magnetic resonance imaging (MRI) is the method of choice in these cases. Nuclear medicine examination techniques such as bone scintigraphy using specially marked granolocyte antibodies are alternatives to be considered for the evaluation of activated chronic osteomyelitis. CT exams are only rarely performed for the diagnosis of chronic osteomyelitis if a bone sequester can not be proven by either x-ray or MRI.     

Usefulness of single photon emission computed tomography imaging in the detection of lumbar vertebral metastases from prostate cancer

Objective:   To determine whether single photon emission computed tomography (SPECT) is useful in the detection of prostate cancer bone metastases in the lumbar vertebrae.
Methods:   Thirty-nine patients (12 with benign prostatic hyperplasia, 27 with prostate cancer) were considered and submitted to bone SPECT. All of them had increased uptake in lumbar vertebrae on bone scintigraphy. In those with prostate cancer, definitive diagnosis of bone metastases was established by magnetic resonance imaging (MRI). SPECT axial images were classified into five accumulation patterns: mosaic, large hot, diffuse, peripheral, and articular (or pediculate). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of bone SPECT were calculated.
Results:   Overall, 116 vertebral lesions (49 metastatic, 67 degenerative) were studied. Mosaic, large hot and diffuse patterns were more frequently associated with metastatic lesions (84.2%, 70.3%, and 63.1% of the cases, respectively). On the other hand, peripheral and articular (or pediculate) patterns were mostly ascribed to degenerative lesions (100% and 87.5% of the cases, respectively). Sensitivity, specificity, PPV and NPV of bone SPECT were 95.9% (47/49), 73.1% (49/67), 72.3% (47/65), and 96.1% (49/51), respectively.
Conclusions:   Bone SPECT provides better accuracy than bone scintigraphy in differential diagnosis of lumbar vertebral lesions from prostate cancer.     

Sinnvolle bildgebende Diagnostik des lokal fortgeschrittenen Prostatakarzinoms

Prostate cancer is one of the principal medical problems facing the male population in developed countries with an increasing need for sophisticated imaging techniques and risk-adapted treatment options. This article presents an overview of the current imaging procedures in the diagnosis of locally advanced prostate cancer. Apart from conventional gray-scale transrectal ultrasound (TRUS) as the most frequently used primary imaging modality we describe computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). CT and MRI not only allow assessment of prostate anatomy but also a specific evaluation of the pelvic region. Color-coded and contrast-enhanced ultrasound, real-time elastography, dynamic contrast enhancement in MR imaging, diffusion imaging, and MR spectroscopy may lead to a clinically relevant improvement in the diagnosis of prostate cancer. While bone scintigraphy with (99m)Tc-bisphosphonates is still the method of choice in the evaluation of bone metastasis, whole-body MRI and PET using (18)F-NaF, (18)F-FDG, (11)C-choline, (11)C-acetate, and (18)F-choline as tracers achieve higher sensitivities.     

F-18 NaF PET for detection of bone metastases in lung cancer: accuracy, cost-effectiveness, and impact on patient management.

As bone metastases might be present in lung cancer despite a normal bone scan, we examined various alternatives prospectively. Positron emission tomography using F-18 sodium fluoride (PET) and single photon emission tomography (SPECT) were more sensitive than a planar bone scan. PET was more accurate with a shorter examination time than SPECT but had higher incremental costs. INTRODUCTION: Previous studies have shown that vertebral bone metastases not seen on planar bone scans may be present on F-18 fluoride positron emission tomography (PET) scan or single photon emission computed tomography (SPECT). The purpose of this study was to measure the accuracy, clinical value and cost-effectiveness of tomographic bone imaging. MATERIALS AND METHODS: A total of 103 patients with initial diagnosis of lung cancer was prospectively examined with planar bone scintigraphy (BS), SPECT of the vertebral column and PET using F-18 sodium fluoride (F-18 PET). Receiver operating characteristic (ROC) curve analysis was used for determination of the diagnostic accuracy. A decision-analysis model and the national charge schedule of the German Hospital Association were used for determination of the cost-effectiveness. RESULTS: Thirteen of 33 patients with bone metastases were false negative on BS, 4 on SPECT, and 2 on F-18 PET. The area under the ROC curve was 0.771 for BS, 0.875 for SPECT, and 0.989 for F-18 PET (p < 0.05). As a result of SPECT and F-18 PET imaging, clinical management was changed in 8 (7.8%) and 10 (9.7%) patients. Compared with BS, the costs per additional correctly diagnosed patient were 1272 Euro with SPECT and 2861 Euro with F-18 PET. The threshold for the costs of F-18 PET being more cost-effective than SPECT was 345 EUR. CONCLUSION: Routine performance of tomographic bone imaging improves the therapeutic strategy because of detection of otherwise missed metastases. F-18 PET is more effective than SPECT but is associated with higher incremental costs.