Factors Influencing Visualization of Vertebral Metastases on MR Imaging Versus Bone Scintigraphy

Lumbar Intervertebral Disc and Discovertebral Segment. Part 2: An Imaging Review of Pathologic Conditions With Anatomic Correlation

The lumbar intervertebral disc is a complex anatomic structure that can be affected by a number of distinct pathologic processes. Categories of the disease include degenerative changes, subclinical or overt trauma, infectious lesions, inflammatory insults, metabolic disease, and tumors. Abnormalities affecting the intervertebral disc may assume atypical appearances or alterations may as well mimic pathologic processes related to degeneration that can be asymptomatic. Although the imaging findings of degenerative diseases of the vertebral column have been emphasized extensively, the assembly of pathologic conditions associated with the discovertebral segment has not received adequate attention. This manuscript reviews and illustrates a range of abnormalities affecting the discovertebral segment, providing a detailed analysis of postmortem material, in the realm of a close anatomic-imaging correlation. Knowledge of the characteristic morphology and patterns of abnormal conditions affecting the intervertebral disc and discovertebral segment can help radiologists narrow the differential diagnosis in a broad spectrum of disease processes.

Stereotactic radiotherapy for bone oligometastases

About 60–90% of cancer patients are estimated to develop bone metastases, particularly in the spine.

Bone scintigraphy, computed tomography (CT ) and magnetic resonance imaging (MRI ) are currently used to assess metastatic bone disease; positron emission tomography/computed tomography (PET-CT ) has become more widespread in clinical practice because of its high sensitivity and specificity with about 95% diagnostic accuracy. The most common and well-known radiotracer is 18F-fluorodeoxyglucose (¹⁸FDG); several other PET-radiotracers are currently under investigation for different solid tumors, such as ¹¹C or ¹⁸FDG-choline and prostate specific membrane antigen (PSMA)-PET/CT for prostate cancer. In treatment planning, standard and investigational imaging modalities should be registered with the planning CT so as to best define the bone target volume. For target volume delineation of spine metastases, the International Spine Radiosurgery Consortium (ISRC ) of North American experts provided consensus guidelines. Single fraction stereotactic radiotherapy (SRT ) doses ranged from 12 to 24 Gy; fractionated SRT administered 21–27 Gy in 3 fractions or 20–35 Gy in 5 fractions. After spine SRT, less than 5% of patients experienced grade ≥ 3 acute toxicity. Late toxicity included the extremely rare radiation-induced myelopathy and a 14% risk of de novo vertebral compression fractures.

Abnormal Conditions of the Diskovertebral Segment: MRI With Anatomic-Pathologic Correlation

OBJECTIVE. The purpose of this article is to review the appearance of various abnormalities that affect the lumbar intervertebral disk and diskovertebral segment through anatomic-pathologic correlation in cadavers. CONCLUSION. Familiarity with the pathologic conditions in and around the intervertebral disk is important in recognizing such conditions as a potential source of symptoms. We revisit the principal role of MRI in evaluating these abnormalities and excluding other sources of significant clinical manifestations.

Myxoid Liposarcoma With Skeletal Metastases: Pathophysiology and Imaging Characteristics

Liposarcoma is a commonly occurring soft tissue sarcoma that can be divided into 4 subtypes. Myxoid and round cell liposarcoma (MRCL) represent one of these subtypes and are classified together due to their shared chromosomal translocation. Histologic analysis of MRCL reveals a myxoid matrix with a delicate capillary network and dispersed lipoblasts. Varying degrees of round cell component are also observed, with greater amounts of round cells indicating a higher histologic grade and poorer prognosis. MRCL has a unique pattern of spread due to its initial tendency to spread to extrapulmonary sites. Additionally, skeletal metastases are frequently found in cases of MRCL. While various imaging techniques are used to visualize MRCL and metastases, magnetic resonance imaging is generally the preferred method. This article reviews the pathophysiology and imaging features of MRCL as well as the imaging characteristics, advantages, and drawbacks of multiple imaging modalities for visualizing bone metastases.

Skeletal abnormalities detected by SPECT is associated with increased relapse risk in pediatric acute lymphoblastic leukemia

Objectives

Most children with acute lymphoblastic leukemia (ALL) exhibit skeletal abnormalities. This study aimed to investigate bone lesions detected by whole-body bone single-photon emission computed tomography (SPECT) and its prognostic value in children with ALL.

Methods

A retrospective analysis was performed using whole-body bone SPECT scans obtained from children with ALL in our department between June 2008 and June 2012. A total of 166 children newly diagnosed with ALL were included, and the patients were divided into two groups: patients with positive and negative SPECT scans. We compared the clinical characteristics of the two groups and analyzed the relationship between the skeletal abnormalities detected by SPECT and prognosis.

Results

Among the 166 patients, bone scintigraphic abnormalities was detected by SPECT scan in sixty-four patients (38.6%). The most common site was the limbs. There were no significant differences in age, gender, WBC count at diagnosis, risk group and minimal residual disease (MRD) level between SPECT-positive patients and their SPECT-negative counterparts. The event-free and overall survival rates were higher in SPECT-positive patients, but the difference was not statistically significant. However, patients with positive SPECT scans, especially those with multifocal abnormalities (≥3 sites), had a higher rate of relapse (P < 0.05). Multivariate analyses identified that abnormal SPECT scan (HR = 3.547, P = 0.015) was an independent relapse risk.

Conclusion

Children with ALL and multiple skeletal abnormalities will suffer from relapse. Abnormal SPECT scan was associated with increased relapse risk which might be a potential relapse marker for ALL children.

Management of metastatic castration-resistant prostate cancer: A focus on radium-223: Opinions and suggestions from an expert multidisciplinary panel

Radium-223, a calcium mimetic bone-seeking radionuclide that selectively targets bone metastases with alpha particles, is approved for the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) and symptomatic bone metastases. In patients with mCRPC, treatment with radium-223 has been associated with survival benefit, regardless of prior docetaxel use, and also has a positive impact on symptomatic skeletal events and quality of life. Radium-223 is best suited for patients with symptomatic mCRPC and bone-predominant disease and no visceral metastases, and may lead to better outcomes when given early in the course of the disease. An expert multidisciplinary panel convened in Milan, Italy to review the current best-evidence literature on radium-223 and to convey their personal expertise with the use of radium-223 and identify possible strategies for best practice. This article summarizes the best available evidence for the use of radium-223, discusses the essential role of the multidisciplinary team in delivering effective treatment for mCRPC, clarifies pre- and post-treatment evaluation and monitoring, and outlines future scenarios for radium-223 in the treatment of men with MCRPC.

Bone Metastases of Hepatocellular Carcinoma: Appearance on MRI Using a Standard Abdominal Protocol

OBJECTIVE

The purpose of this study is to describe the MRI features of hepatocellular carcinoma (HCC) bone metastases.

MATERIALS AND METHODS

Thirty-three consecutive patients were included. Two radiologists performed qualitative and quantitative analysis. The coordinator searched for clinical and epidemiologic features related to patients and their primary liver tumors. Earlier MRI studies were also reviewed to determine whether bone metastases were already present and prospectively identified. Descriptive statistics and the Lin concordance correlation coefficient were used.

RESULTS

Chronic hepatitis C virus infection was the most common cause of liver disease (20/32; 62.5%), and diffuse and multifocal HCC were the most frequent types of liver HCCs (28/33; 84.8%). Most lesions were located at the spine (109/155; 70.3%), with high signal intensity on fat-suppressed T1-weighted (54/62; 87.1%) and T2-weighted (53/62; 85.5%) images. Bone metastases were predominantly nodular (48/62; 77.4%), confined to the vertebral body (40/60; 66.7%), and best visualized at the arterial phase (40/62; 64.5%). The ring pattern of enhancement was present in 23 of 62 lesions, and the remaining lesions showed diffuse enhancement. Thirty-five of 62 (56.4%) bone metastases showed arterial peak of enhancement. In 13 of 33 (39.9%) patients, bone metastases were not prospectively reported.

CONCLUSION

Most patients with bone metastases had chronic hepatitis C virus infection and diffuse or multifocal HCC. Metastases are most commonly appreciated as hypervascular focal moderately intensely enhancing nodular masses on the hepatic arterial dominant phase images, with concomitant moderately high signal intensity on fat-suppressed T1- and T2-weighted images.

Comparison of CE-FDG-PET/CT with CE-FDG-PET/MR in the evaluation of osseous metastases in breast cancer patients

BACKGROUND

Despite improvements in treatments, metastatic breast cancer remains difficult to cure. Bones constitute the most common site of first-time recurrence, occurring in 40-75% of cases. Therefore, evaluation for possible osseous metastases is crucial. Technetium 99 ((99)Tc) bone scintigraphy and fluorodexossyglucose (FDG) positron emission tomography (PET)-computed tomography (PET-CT) are the most commonly used techniques to assess osseous metastasis. PET magnetic resonance (PET-MR) imaging is an innovative technique still under investigation. We compared the capability of PET-MR to that of same-day PET-CT to assess osseous metastases in patients with breast cancer.

METHODS

One hundred and nine patients with breast cancer, who underwent same-day contrast enhanced (CE)-PET-CT and CE-PET-MR, were evaluated. CE-PET-CT and CE-PET-MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Binomial confidence intervals and a χ(2) test were used for categorical data, and paired t-test was used for the SUVmax data; a non-informative prior Bayesian approach was used to estimate and compare the specificities.

RESULTS

Osseous metastases affected 25 out 109 patients. Metastases were demonstrated by CE-PET-CT in 22 out of 25 patients (88%±7%), and by CE-PET-MR in 25 out of 25 patients (100%). CE-PET-CT revealed 90 osseous metastases and CE-PET-MR revealed 141 osseous metastases (P<0.001). The estimated sensitivity of CE-PET-CT and CE-PET-MR were 0.8519 and 0.9630, respectively. The estimated specificity for CE-FDG-PET-MR was 0.9884. The specificity of CE-PET-CT cannot be determined from patient-level data, because CE-PET-CT yielded a false-positive lesion in a patient who also had other, true metastases.

CONCLUSIONS

CE-PET-MR detected a higher number of osseous metastases than did same-day CE-PET-CT, and was positive for 12% of the patients deemed osseous metastasis-negative on the basis of CE-PET-CT.

Receptor conversion in carcinoma breast metastatic to the bone marrow

Breast cancer is the first in the incidence of malignancies among women. The documented frequency of osseous metastasis from breast cancer is about 12.8 %. Although breast cancer cells have been documented in the bone marrow in autopsy, haematological manifestations due to metastatic disease to the marrow is rare. The prognosis of these cases is dismal and improper management worsen the condition further. IHC for ER, PR & Her 2/neu status plays a vital role in ascertaining the treatment protocol both in primary tumors as well as metastatic or recurrent tumors. Receptor conversion has been documented in metastatic and recurrent cases. We report a case of 65 year female with a history of ER, PR positive and Her 2/neu negative carcinoma breast 3½ years back, presented with anemia and low back ache diagnosed as metastatic breast carcinoma to bone marrow with receptor conversion.

Magnetic resonance imaging of pelvic metastases in male patients

Magnetic resonance (MR) imaging offers a noninvasive tool for diagnosis of primary and metastatic pelvic tumors. The diagnosis of a pelvic metastatic lesion implies an adverse prognosis and dictates the management strategies. Knowledge of normal MR imaging anatomy of the pelvis and the signal characteristics of normal and abnormal structures is essential for accurate interpretation of pelvic MR imaging. This article reviews imaging manifestations of nodal, visceral, and musculoskeletal metastatic lesions of the pelvis along with current and evolving MR imaging techniques.

[Molecular multimodal hybrid imaging in prostate and bladder cancer]

Since the introduction of combined radiologic-nuclear imaging procedures like PET/CT and PET/MRI, new and promising diagnostic tools in bladder and prostate cancer imaging are available to physicians. Although PET-based hybrid imaging in bladder cancer is currently utilized only in selected cases, an increase in PET imaging can be observed in prostate cancer due to the development of cancer-specific PET tracers. Especially novel ligands of prostate-specific membrane antigen (PSMA) exhibit great potential to effectively influence future staging of prostate cancer. However, before recommendations for implication in routine staging can be given, evaluation in the context of prospective multicenter clinical trials are mandatory.

Fibrocartilaginous intramedullary bone forming tumor of the distal femur mimicking osteosarcoma

Fibrocartilaginous dysplasia (FCD) has occasionally led to a misdiagnosis and wrong decision which can significantly alter the outcome of the patients. A 9-yr-old boy presented with pain on his left distal thigh for 6 months without any trauma history. Initial radiographs showed moth eaten both osteolytic and osteosclerotic lesions and biopsy findings showed that the lesion revealed many irregular shaped and sclerotic mature and immature bony trabeculae. Initial diagnostic suggestions were varied from the conventional osteosarcoma to low grade central osteosarcoma or benign intramedullary bone forming lesion, but close observation was done. This study demonstrated a case of unusual fibrocartilaginous intramedullary bone forming tumor mimicking osteosarcoma, so that possible misdiagnosis might be made and unnecessary extensive surgical treatment could be performed. In conclusion, the role of orthopaedic oncologist as a decision maker is very important when the diagnosis is uncertain.

[Imaging diagnostics of advanced prostate cancer]

The diagnostic approach to prostate cancer is still a big challenge for the treating physician. Regarding an individualized and risk-adapted evaluation of different therapeutic options, precise diagnostic tools are crucial to accurately distinguish between localized and advanced prostate cancer. Imaging of advanced prostate cancer is currently changing due to numerous technical innovations. While choline-based hybrid positron emission tomography-computed tomography (PET/CT) has been established as an important diagnostic tool in clinical imaging of advanced prostate cancer, well-investigated methods, such as magnetic resonance imaging (MRI) and bone scintigraphy are currently expanding the diagnostic potential due to technical improvements. The specific use of imaging for advanced prostate cancer may help to offer the patient a well-tailored oncologic therapy. Further research is needed to evaluate whether this individualized therapy can consistently improve the prognosis of patients suffering from advanced prostate cancer.

Whole-body diffusion-weighted MRI compared with (18)F-NaF PET/CT for detection of bone metastases in patients with high-risk prostate carcinoma

OBJECTIVE

The purpose of this study was to evaluate the accuracy of whole-body diffusion-weighted MRI (DWI) and (18)F-NaF PET/CT for detection of bone metastases in patients with high-risk prostate cancer.

SUBJECTS AND METHODS

Both patient- and lesion-based analyses were performed on 49 consecutive patients (median age, 67 years; age range, 57-80 years) with recently diagnosed high-risk prostate cancer. All patients underwent bone scintigraphy, whole-body MRI including DWI and (18)F-NaF PET/CT before treatment. Bone scintigraphy, conventional MR images, and follow-up images were used as the standard of reference to evaluate (18)F-NaF PET/CT and DWI.

RESULTS

On patient-based analysis, five patients had skeletal metastases on reference imaging that both DWI and (18)F-NaF PET/CT could verify, and (18)F-NaF PET/CT and DWI showed false-positive findings in four and one patient, respectively. With lesion-based analysis, (18)F-NaF PET/CT and DWI showed nine and five true-positive lesions, zero and four false-negative lesions, and seven and two false-positive lesions, respectively. Two patients with uncountable bone metastases were analyzed separately. In these patients, (18)F-NaF PET/CT showed more bone metastases than did DWI.

CONCLUSION

We believe (18)F-NaF PET/CT is a sensitive modality for detection of bone metastases caused by prostate cancer. Whole-body DWI shows a higher specificity but lower sensitivity than (18)F-NaF PET/CT. Future studies with a larger patient cohort along with analyses of costs and clinical availability are needed before implementation of these methods can be considered.

Myxoid liposarcoma with negative features on bone scan and [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography

Background

Myxoid liposarcoma occurs in middle age, and is characterized by extrapulmonary metastasis, including bone metastasis. Bone scans and [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) are widely used for assessment of tumor extension, including vertebral metastasis. However, both methods have a low positive rate with regard to vertebral metastasis arising from myxoid liposarcoma. This is particularly true for bone scans for intramedullary lesions that have no cortical involvement.

Case presentation

We present the case of a 53-year-old male with myxoid liposarcoma in the leg. He had been treated for multiple metastases over a ten-year period, and was experiencing back pain due to a pathological fracture in the second lumbar vertebra (L2). Magnetic resonance imaging of all the vertebrae showed abnormal signal intensity suggestive of metastasis in eight vertebrae, and revealed extraskeletal extension in three vertebrae. Bone scans and FDG-PET were negative except for the L2 fracture which was indicated on a bone scan.

Conclusions

Both bone scans and FDG-PET can be negative in cases of vertebral metastasis that arise from myxoid liposarcoma, even when extraskeletal extensions are present. Similarly, even a fractured vertebra may not always be visible on FDG-PET.

Imaging of spine neoplasm

Although most often back pain is of benign origin, it can occasionally be a harbinger of a more serious spinal condition, including spine neoplasm. Knowledge of the typical clinical history of spinal tumors and an understanding of the innervation of the spine and surrounding supporting structures may allow us to better understand when to pursue advanced imaging in the evaluation of spinal pain syndromes. Many radiologists have divided the differential diagnosis of neoplasms of the spine into compartments. These compartments include the extradural compartment, intradural/extramedullary compartment, and the intramedullary compartment.

Prediction of survival benefit using an automated bone scan index in patients with castration-resistant prostate cancer

What's known on the subject? and What does the study add? A bone scan index (BSI) can quantify the extent of bone involvement and response to treatment, but it has not been widely accepted, because of its time-consuming nature. The study is the first to demonstrate that automated BSI calculated with a computer-assisted diagnosis system is effective in judging the chemotherapeutic response of bone metastatic lesions in patients with castration-resistant prostate cancer.

OBJECTIVE

• To evaluate the value of an automated bone scan index (aBSI), calculated using a computer-assisted diagnosis system, to indicate chemotherapy response and to predict prognosis in patients with castration-resistant prostate cancer (CRPC) with bone metastasis.

PATIENTS AND METHODS

• Forty-two consecutive CRPC patients underwent taxane-based chemotherapy between November 2004 and March 2011 at our institution. • The aBSIs were retrospectively calculated at the diagnosis of CRPC and 16 weeks after starting chemotherapy. • Cox proportional hazards regression models were applied to multivariate analyses with and without aBSI response in addition to the basic model. • Based on the difference in the concordance index (c-index) between each model, the prognostic relevance of adding the aBSI response was determined.

RESULTS

• A decrease in aBSI was found in 28 patients (66.7%), whereas a response was shown by bone scan in only 23.8% of patients. • Patients with a reduction in aBSI had longer overall survival (OS) in comparison with the other patients (P= 0.0157). • Multivariate analysis without aBSI response showed that performance status (P= 0.0182) and PSA response (P= 0.0375) were significant prognosticators. • By adding the aBSI response to this basic model, the prognostic relevance of the model was improved with an increase in the c-index from 0.621 to 0.660.

CONCLUSIONS

• The aBSI reflected the chemotherapy response in bone metastasis. • The index detected small changes of bone metastasis response as quantified values and was a strong prognostic indicator for patients with CRPC.

ACR Appropriateness Criteria® posttreatment follow-up of prostate cancer

Although prostate cancer can be effectively treated, recurrent or residual disease after therapy is not uncommon and is usually detected by a rise in prostate-specific antigen. Patients with biochemical prostate-specific antigen relapse should undergo a prompt search for the presence of local recurrence or distant metastatic disease, each requiring different forms of therapy. Various imaging modalities and image-guided procedures may be used in the evaluation of these patients. Literature on the indications and usefulness of these radiologic studies and procedures in specific clinical settings is reviewed. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Imaging in prostate cancer staging: present role and future perspectives

Despite recent improvements in detection and treatment, prostate cancer continues to be the most common malignancy and the second leading cause of cancer-related mortality. Thus, although survival rate continues to improve, prostate cancer remains a compelling medical health problem. The major goal of prostate cancer imaging in the next decade will be more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information in order to plan the most appropriate therapeutic strategy. No consensus exists regarding the use of imaging for evaluating primary prostate cancer. However, conventional and functional imaging are expanding their role in detection and local staging and, moreover, functional imaging is becoming of great importance in oncologic management and monitoring of therapy response. This review presents a multidisciplinary perspective on the role of conventional and functional imaging methods in prostate cancer staging.

A spinal cord astrocytoma and its concurrent osteoblastic metastases at the time of the initial diagnosis: a case report and literature review

Bone metastasis from a spinal cord astrocytoma has been reported only twice in the English medical literature. It is generally known that bone metastasis is found after the initial diagnosis with/without intervening surgery rather than being found at the time of the diagnosis of astrocytoma. The purpose of this article is to report for the first time a case of concurrent bone metastasis from a spinal cord astrocytoma at the time of diagnosing the spinal cord astrocytoma.

Prostate cancer imaging: what surgeons, radiation oncologists, and medical oncologists want to know

OBJECTIVE

The purpose of this article is to discuss the information that is important to note in imaging reports of patients with prostate cancer.

CONCLUSION

Accurate staging through imaging is an integral part of prostate cancer management. Ultrasound, CT, bone scanning, and MRI are used for prostate cancer patients to assess the primary tumor, lymph node status, and bone metastasis. Accurate reporting of images is crucial for effective cancer treatment.

Imaging of skeletal metastases in myxoid liposarcoma

Unlike other soft tissue sarcomas, myxoid/round cell liposarcoma (MRCL) has a tendency to spread to extrapulmonary sites but bone metastases are thought to be uncommon. In case reports, negative bone scintigraphy has been noted in patients with myxoid/round cell liposarcoma and bone metastases but the prevalence and optimal method of diagnosis of bone metastases in this common subtype of liposarcoma are unclear. In an attempt to answer these questions, data were obtained from a prospective database of patients with sarcoma, including MRCL, and the diagnostic imaging used was examined. A variety of imaging tools were used including plain X-rays, bone scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI). Eight patients (4.3%) developed skeletal metastases all of which were positive on MRI. Bone scintigraphy was negative in two out of four cases, CT was negative in six out of seven, and X-rays were negative in four. Radiography and CT measure mainly cortical bone involvement, whereas MRI examines bone marrow. When investigating patients with MRCL for bone pain, negative X-rays and bone scans do not rule out bone metastases. In our experience, MRI provides the most sensitive technique for the diagnosis of bone metastases in MRCL.

Imaging metastatic bone disease from carcinoma of the prostate

Imaging bone metastases from prostate cancer presents several challenges. The lesions are usually sclerotic and appear late on the conventional X-ray. Bone scintigraphy is the mainstay of lesion detection, but is often not suitable for assessment of treatment response, particularly because of a ‘flare’ phenomenon after therapy. Magnetic resonance imaging is increasingly used in assessment, and newer techniques allow quantitation. In addition to ¹⁸F-fluorodeoxyglucose (¹⁸FDG), newer PET isotopes are also showing promise in lesion detection and response assessment. This article reviews the available imaging modalities for evaluating prostatic bony metastases, and links them to the underlying pathological changes within bone lesions.

Imaging response to systemic therapy for bone metastases

In patients with osteotropic primary tumours such as breast and prostate cancer, imaging treatment response of bone metastases is essential for the clinical management. After treatment of skeletal metastases, morphological changes, in particular of bone structure, occur relatively late and are difficult to quantify using conventional X-rays, CT or MRI. Early treatment response in these lesions can be assessed from functional imaging techniques such as dynamic contrast-enhanced techniques by MRI or CT and by diffusion-weighted MRI, which are quantifiable. Among the techniques within nuclear medicine, PET offers the acquisition of quantifiable parameters for response evaluation. PET, therefore, especially in combination with CT and MRI using hybrid techniques, holds great promise for early and quantifiable assessment of treatment response in bone metastases. This review summarises the classification systems and the use of imaging techniques for evaluation of treatment response and suggests parameters for the early detection and quantification of response to systemic therapy.

PET Imaging of Prostate Cancer: Other Tracers

There are significant limitations in the current options for imaging of patients with prostate carcinoma. Although fluorodeoxyglucose is the mainstay of clinical imaging, many other isotope and tracer combinations can be imaged with PET. One of the strengths of nuclear imaging lies in the variety of radiotracers capable of being imaged. In the last 15 years, various compounds have been studied in the hope of identifying the ideal imaging agent for prostate cancer. In this article, the use of imaging agents other than fluorodeoxyglucose, choline, and acetate is discussed.

An unusual case of spinal column metastasis after orthotopic transplantation for cardiac sarcoma

The authors describe a patient who underwent orthotopic cardiac transplantation after an undifferentiated cardiac sarcoma was diagnosed. While receiving immunosuppressive therapy, the patient developed spinal column metastases and cauda equina syndrome requiring surgical decompression and stabilization. This occurred despite an exhaustive search for metastatic disease prior to the transplantation. To the authors' knowledge, this represents the first reported case of an undifferentiated cardiac sarcoma metastasis to the spine. This previously healthy 18-year-old woman presented with a myocardial infarction. Investigations revealed a left atrial tumor, which was resected. Following local recurrence, the patient underwent extensive studies to rule out systemic disease. Orthotopic heart-lung transplantation was then performed. While receiving postoperative immunosuppressive therapy the patient presented with cauda equina syndrome secondary to metastatic tumor compression at the L-5 level. Despite a comprehensive screening process to exclude metastatic disease prior to transplantation, spinal metastases occurred while this patient was receiving immunosuppressive therapy. This represents a previously unreported and clinically significant complication for undifferentiated cardiac sarcoma.

Health technology assessment of magnetic resonance imaging of the spine and bone marrow

The high spatial resolution and the lack of ionizing radiation, makes magnetic resonance imaging the method of choice for imaging most spinal pathology, especially if associated with neurological symptoms. However, due to the high sensitivity of MR imaging, careful correlation between imaging findings and clinical findings is important to ensure appropriate treatment. Substituting radiographic evaluations for rapid MRI in the primary care setting may offer little additional benefit to patients. It may even increase the costs of care but the decisions about the use of imaging depend on judgments concerning whether the small observed improvement in outcome justifies additional cost. Because the presence of an abscess is a major factor in deciding between conservative and surgical treatment, MRI plays an essential role in the decision-making process concerning the treatment of spondylodiscitis. MR is also the method of choice for quantitative evaluation of bone marrow in lymphoma patients when a crucial therapeutic decision has to be made or for the qualitative evaluation of the spinal cord if compression is suspected in primary spinal malignancy or metastatic disease.

Magnetic resonance imaging of bone marrow in oncology, Part 2

Magnetic resonance imaging plays an integral role in the detection and characterization of marrow lesions, planning for biopsy or surgery, and post-treatment follow-up. To evaluate findings in bone marrow on MR imaging, it is essential to understand the normal composition and distribution of bone marrow and the changes in marrow that occur with age, as well as the basis for the MR signals from marrow and the factors that affect those signals; these points have been reviewed and illustrated in part 1 of this two-part article. Part 2 will emphasize the practical application of MR imaging to facilitate differentiation of normal marrow, tumor, and treatment-related marrow changes in oncology patients, and will review complementary MR techniques under development.

Imaging prostate cancer: a multidisciplinary perspective

The major goal for prostate cancer imaging in the next decade is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. No consensus exists regarding the use of imaging for evaluating primary prostate cancers. Ultrasonography is mainly used for biopsy guidance and brachytherapy seed placement. Endorectal magnetic resonance (MR) imaging is helpful for evaluating local tumor extent, and MR spectroscopic imaging can improve this evaluation while providing information about tumor aggressiveness. MR imaging with superparamagnetic nanoparticles has high sensitivity and specificity in depicting lymph node metastases, but guidelines have not yet been developed for its use, which remains restricted to the research setting. Computed tomography (CT) is reserved for the evaluation of advanced disease. The use of combined positron emission tomography/CT is limited in the assessment of primary disease but is gaining acceptance in prostate cancer treatment follow-up. Evidence-based guidelines for the use of imaging in assessing the risk of distant spread of prostate cancer are available. Radionuclide bone scanning and CT supplement clinical and biochemical evaluation (prostate-specific antigen [PSA], prostatic acid phosphate) for suspected metastasis to bones and lymph nodes. Guidelines for the use of bone scanning (in patients with PSA level > 10 ng/mL) and CT (in patients with PSA level > 20 ng/mL) have been published and are in clinical use. Nevertheless, changes in practice patterns have been slow. This review presents a multidisciplinary perspective on the optimal role of modern imaging in prostate cancer detection, staging, treatment planning, and follow-up.

In vivo imaging of prostate cancer involving bone in a mouse model

BACKGROUND

We compared the abilities of clinically relevant imaging modalities to quantify prostate cancer involving bone in a mouse model. Such non-invasive methods are needed pre-clinically to understand tumor biology and to evaluate therapy.

METHODS

Human prostate cancer cells (MDA PCa 2b) or vehicle were injected into the right or left femur of SCID mice (n = 8). Radiography, computed tomography, and magnetic resonance imaging were performed 5 and 8 weeks later (n = 7). Bone scintigraphy (n = 6) was also performed at week 8. Imaging findings were compared with histology and correlated with contemporaneous serum prostate-specific antigen levels.

RESULTS

Among the modalities evaluated, only MR imaging delineated prostate tumors involving bone. Tumor volume assessed by MR imaging correlated with PSA levels (R(2) = 0.87, P < 0.001). MR imaging of tumors corresponded with histology. Imaging of mineralized bone by CT corresponded with histology.

CONCLUSION

In a mouse model, prostate tumors involving bone can be quantified using MR imaging.

Diagnostic value of MRI in comparison to scintigraphy, PET, MS-CT and PET/CT for the detection of metastases of bone

The initial localization of metastases in the bone in patients with solid tumors has a relatively good prognosis in comparison with visceral metastasization. The early detection of bone marrow metastases allows for a rapid initiation of therapy and a subsequent reduction in the morbidity rate. Modern MRI is superior to the 30-year-old skeletal scintigraphy and bone marrow scintigraphy with respect to sensitivity, specificity, as well as the extent of osteal metastasis. MRI provides substantial, therapy-relevant additional information. MSCT plays an important role in the management of cancer patients in clinical routine and gives an excellent survey of the axial skeleton by demonstrating osteolytic and osteoblastic metastases. Extensive comparative studies of MRI with 18F-FDG-PET and 18F-fluoride-PET have not yet been carried out. Whole body MRI is a very promising new staging method for the oncological diagnosis of solid tumors and the detection of osteal metastases. The adoption of 18F-FDG-PET and 18F-fluoride-PET FDG as well as the side by side PET-CT image fusion and the two in one PET/CT examinations appears to be slightly less sensitive to whole body MRI in the detection of osteal metastases. Larger, prospective multicenter studies are necessary to establish these as new, promising methods for the detection of osteal metastases.

Radiology of metastatic spine cancer

Radiologic imaging is an essential component of current spinal cancer diagnosis and treatment algorithms and is used for cancer diagnosis,determination of tumor extent for treatment planning, and subsequent assessment of therapy efficacy on follow-up.

Sensitivity and specificity of thallium-201 scintigraphy for the diagnosis of malignant vertebral fractures

OBJECTIVE

To evaluate the accuracy of thallium-201 (201TI) scintigraphy in distinguishing a benign from a malignant recent non-traumatic vertebral fracture.

METHODS

STUDY DESIGN--Single center, prospective study. PARTICIPANTS--Patients hospitalized for a recent non-traumatic vertebral fracture. EVALUATION--Usual clinical, laboratory and radiological assessment; 201TI vertebral scintigraphy: patients were injected with iv 3 mCi 201TI. Early and delayed images of the fractured vertebra were obtained. DATA ANALYSIS--(1) Two examinators, unaware of the other findings, rated the images as hyperfixation or not of the fractured vertebra; (2) the ratio (average count per pixel of the fractured vertebra/normal adjacent vertebrae) were calculated. The FINAL DIAGNOSIS was established on the result of vertebral biopsy or on follow-up.

RESULTS

Twenty-one patients were included. The final diagnosis was a benign vertebral fracture in 14 patients and a malignant vertebral fracture in 7. The sensitivity, specificity, positive and negative predictive values for a malignant fracture on early 201TI vertebral scintigraphy images were 28.6, 92.9, 66.6, and 72.2%, respectively, and on delayed images were 28.6, 100, 100, and 73.7%, respectively. The ratio of lesioned over normal tissue was not increased in malignant, compared with benign fractures.

CONCLUSION

The weak sensitivity does not support the wide use of 201TI bone scintigraphy to distinguish a benign from a malignant recent non traumatic vertebral fracture. However, the high specificity suggests that such evaluation might be proposed prior to vertebral biopsy in some difficult cases.