Radiographic imaging of musculoskeletal neoplasia

Bone Tumor Risk Stratification and Management System: A Consensus Guideline from the ACR Bone Reporting and Data System Committee

The assessment and subsequent management of a potentially neoplastic bone lesion seen at diagnostic radiography is often complicated by diagnostic uncertainty and inconsistent management recommendations. Appropriate clinical management should be directed by risk of malignancy. Herein, the ACR-sponsored Bone Reporting and Data System (Bone-RADS) Committee, consisting of academic leaders in the fields of musculoskeletal oncology imaging and orthopedic oncology, presents the novel Bone-RADS scoring system to aid in risk assignment and provide risk-aligned management suggestions. When viewed in the proper clinical context, a newly identified bone lesion can be risk stratified as having very low, low, intermediate, or high risk of malignancy. Radiographic features predictive of risk are reviewed include margination, pattern of periosteal reaction, depth of endosteal erosion, pathological fracture, and extra-osseous soft tissue mass. Other radiographic features predictive of histopathology are also briefly discussed. To apply the Bone-RADS scoring system to a potentially neoplastic bone lesion, radiographic features predictive of risk are each given a point value. Point values are summed to yield a point total, which can be translated to a Bone-RADS score (1-4) with corresponding risk assignment (very low, low, intermediate, high). For each score, evidence-based and best practice consensus management suggestions are outlined. Examples of each Bone-RADS scores are presented, and a standardized diagnostic radiography report template is provided.

Arthroscopic treatment of diffuse pigmented villonodular synovitis of the elbow

INTRODUCTION

Pigmented villonodular synovitis (PVNS) is a rare pathology of the elbow, but presents a risk of progression with cartilage destruction. Surgical treatment consists in synovectomy, as complete as possible. Arthroscopy is an excellent tool for the exploration and treatment of intra-articular lesions in the elbow, but the results in PVNS of the elbow have never been evaluated. The aim of this study was to assess the recurrence rate of PVNS of the elbow after arthroscopic synovectomy, and secondarily to assess pain, joint range of motion, functional scores and complication rate.

MATERIAL AND METHODS

We performed a retrospective study of a continuous series of 8 patients operated on between February 2012 and February 2019, with a mean age of 43.7 years. The operated side was the dominant side in 75% of cases. Surgery consisted in the most complete synovectomy possible, performed arthroscopically. Recurrence, clinical evaluation, with pain at rest and on mpvement on visual analogue scale (VAS) and joint range of motion, functional MEPS and DASH scores, and any complications were collected.

RESULTS

At a mean 66.4 months' follow-up, 2 patients required revision surgery for recurrence. At the last follow-up, VAS for pain at rest was 0.9 and 1.9 for pain on movement. MEPS score was 85.6 and DASH score 82.2. No neurological, vascular or infectious complications of arthroscopic synovectomy were found in our series.

DISCUSSION

Arthroscopic synovectomy in the treatment of PVNS of the elbow was a reliable and safe therapeutic alternative, with a low complications rate and 2 cases of recurrence (25%) in our study. This was the first study to report the results of arthroscopic surgical treatment of elbow PVNS.

LEVEL OF EVIDENCE

IV Retrospective study without control group.

Magnetic resonance imaging in differentiating between aggressive and non-aggressive bone tumors

BACKGROUND

While radiography remains essential in the initial evaluation of bone lesions, tissue biopsy or further imaging is often required to clarify indeterminate radiographic features. Magnetic resonance imaging (MRI) assists radiologists in evaluating lesions with indeterminate features as it has advantages in delineating tumorous tissues and bone marrow.

PURPOSE

To evaluate the association factors of MRI for bony aggressiveness.

MATERIAL AND METHODS

A retrospective analysis of 226 MRI examinations from patients diagnosed with bone tumors in a tertiary hospital during 2008-2018 was performed. All the MR images were interpreted by musculoskeletal radiologists without diagnostic information. The bony lesions were categorized into aggressive and non-aggressive groups using tumor margin, cortical changes, periosteal reaction, joint extension, extraosseous soft tissue involvement, tumor homogeneity, and enhancement pattern from the MR images. Univariable and multivariable analysis were applied for each feature on the MRI scans. In addition, sensitivity and specificity were calculated for MRI diagnoses of aggressive bone lesions.

RESULTS

In total, 180 aggressive and 46 non-aggressive bone lesions were examined on MRI. The sensitivity and specificity of MRI for differentiating between aggressive and non-aggressive bone lesions were 98.89% and 50%, respectively. Ill-defined margin, cortical break, cortical signal changes, sunburst and Codman's triangle periosteal reaction, joint extension, and tumoral and heterogeneous enhancement could be predictive signs for aggressive bone lesions.

CONCLUSION

MRI can be a valuable tool to assist in distinguishing aggressive from non-aggressive bone lesions. In cases of indeterminate radiographic features, MRI could be used as an additional imaging to improve diagnostic accuracy and could reduce unnecessary invasive procedures.

Comparing the blood oxygen level–dependent fluctuation power of benign and malignant musculoskeletal tumors using functional magnetic resonance imaging

Purpose

The aim of this study is to compare the blood oxygen level–dependent (BOLD) fluctuation power in 96 frequency points ranging from 0 to 0.25 Hz between benign and malignant musculoskeletal (MSK) tumors via power spectrum analyses using functional magnetic resonance imaging (fMRI).

Materials and methods

BOLD-fMRI and T1-weighted imaging (T1WI) of 92 patients with benign or malignant MSK tumors were acquired by 1.5-T magnetic resonance scanner. For each patient, the tumor-related BOLD time series were extracted, and then, the power spectrum of BOLD time series was calculated and was then divided into 96 frequency points. A two-sample t-test was used to assess whether there was a significant difference in the powers (the “power” is the square of the BOLD fluctuation amplitude with arbitrary unit) of each frequency point between benign and malignant MSK tumors. The receiver operator characteristic (ROC) analysis was used to assess the diagnostic capability of distinguishing between benign and malignant MSK tumors.

Results

The result of the two-sample t-test showed that there was significant difference in the power between benign and malignant MSK tumor at frequency points of 58 (0.1508 Hz, P = 0.036), 59 (0.1534 Hz, P = 0.032), and 95 (0.247 Hz, P = 0.014), respectively. The ROC analysis of mean power of three frequency points showed that the area of under curve is 0.706 (P = 0.009), and the cutoff value is 0.73130. If the power of the tumor greater than or equal to 0.73130 is considered the possibility of benign tumor, then the diagnostic sensitivity and specificity values are 83% and 59%, respectively. The post hoc analysis showed that the merged power of 0.1508 and 0.1534 Hz in benign MSK tumors was significantly higher than that in malignant ones (P = 0.014). The ROC analysis showed that, if the benign MSK tumor was diagnosed with the power greater than or equal to the cutoff value of 1.41241, then the sensitivity and specificity were 67% and 68%, respectively.

Conclusion

The mean power of three frequency points at 0.1508, 0.1534, and 0.247 Hz may potentially be a biomarker to differentiate benign from malignant MSK tumors. By combining the power of 0.1508 and 0.1534 Hz, we could better detect the difference between benign and malignant MSK tumors with higher specificity.

Imaging Analyses of Bone Tumors

Despite the evolution in imaging, especially the introduction of advanced imaging technologies, radiographs still are the key for the initial assessment of a bone tumor. Important aspects to be considered in radiographs are the location, shape and size or volume, margins, periosteal reaction, and internal mineralization of the tumor's matrix; careful evaluation of these may provide for accurate diagnosis in >80% of cases. Computed tomography and magnetic resonance imaging are often diagnostic for lesions with typical findings such as the nidus of osteoid osteoma and bone destruction such as in Ewing sarcoma and lymphoma that may be difficult to detect with radiographs; they may also be used for surgical planning. Magnetic resonance imaging accurately determines the intraosseous extent and articular and vascular involvement by the tumor. This article summarizes the diagnostic accuracy of imaging analyses in bone tumors and emphasizes the specific radiographic findings for optimal radiographic diagnosis of the patients with these tumors.

Accuracy of plain radiographs in diagnosing biopsy-proven malignant bone lesions

Background

The diagnosis of primary bone tumours is a three-fold approach based on a combination of clinical, radiological and histopathological findings. Radiographs form an integral part in the initial diagnosis, staging and treatment planning for the management of aggressive/malignant bone lesions. Few studies have been performed where the radiologist’s interpretation of radiographs is compared with the histopathological diagnosis.

Objectives

The study aimed to determine the frequency of bone tumours at a tertiary hospital in South Africa, and, using a systematic approach, to determine the sensitivity and specificity of radiograph interpretation in the diagnosis of aggressive bone lesions, correlating with histopathology. We also determined the inter-observer agreement in radiograph interpretation, calculated the positive and negative predictive values for aggressive/malignant bone tumours and computed the cumulative effect of multiple radiological signs to determine the yield for malignant bone tumours.

Method

A retrospective, descriptive and correlational study was performed, reviewing the histopathological reports of all biopsies performed on suspected aggressive bone lesions during a 3-year period from 2012 to 2014. The radiographs were interpreted by three radiologists using predetermined criteria. The sensitivity and specificity of the readers’ interpretation of the radiograph as ‘benign/non-aggressive’ or ‘aggressive/malignant’ were calculated against the histology, and the inter-rater agreement of the readers was computed using the Fleiss kappa values.

Results

Of the 88 suspected ‘aggressive or malignant’ bone tumours that fulfilled the inclusion criteria, 43 were infective or malignant and 45 were benign lesions at histology. Reader sensitivity in the diagnosis of malignancy/infective bone lesions ranged from 93% to 98% with a specificity of 53% – 73%. The average kappa value of 0.43 showed moderate agreement between radiological interpretation and final histology results. The four radiological signs with the highest positive predictive values were an ill-defined border, wide zone of transition, cortical destruction and malignant periosteal reaction. The presence of all four signs on radiography had a 100% yield for a malignant bone tumour or infective lesion.

Conclusion

The use of a systemic approach in the interpretation of bone lesions on radiographs yields high sensitivity but low specificity for malignancy and infection. The presence of benign bone lesions with an aggressive radiographic appearance necessitates continuation of the triple approach for the diagnosis of primary bone tumours.

The Established Nuclear Medicine Modalities for Imaging of Bone Metastases

Background:

The skeleton is one of the frequent site of metastases in advanced cancer. Prostate, breast and renal cancers mostly metastasize to bone.

Discussion:

Malignant tumors lead to significant morbidity and mortality. Identification of bone lesions is a crucial step in diagnosis of disease at early stage, monitoring of disease progression and evaluation of therapy. Diagnosis of cancer metastases is based on uptake of bone-targeted radioactive tracer at different bone remodeling sites.

Conclusion:

This manuscript summarizes already established and evolving nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET, PET/CT) for imaging of bone metastases.

Anatomic predictors of response and mechanism of action of upper airway stimulation therapy in patients with obstructive sleep apnea

Study Objectives

Upper airway stimulation has been shown to be an effective treatment for some patients with obstructive sleep apnea. However, the mechanism by which hypoglossal nerve stimulation increases upper airway caliber is not clear. Therefore, the objective of this study was to identify the mechanism of action of upper airway stimulation. We hypothesized that, with upper airway stimulation, responders would show greater airway opening in the retroglossal (base of the tongue) region, greater hyoid movement toward the mandible, and greater anterior motion in the posterior, inferior region of the tongue compared with nonresponders.

Methods

Seven participants with obstructive sleep apnea who had been successfully treated with upper airway stimulation (responders) and six participants who were not successfully treated (nonresponders) underwent computed tomography imaging during wakefulness with and without hypoglossal nerve stimulation. Responders reduced their apnea-hypopnea index (AHI) by 22.63 ± 6.54 events per hour, whereas nonresponders had no change in their AHI (0.17 ± 14.04 events per hour). We examined differences in upper airway caliber, the volume of the upper airway soft tissue structures, craniofacial relationships, and centroid tongue and soft palate movement between responders and nonresponders with and without hypoglossal nerve stimulation.

Results

Our data indicate that compared with nonresponders, responders had a smaller baseline soft palate volume and, with stimulation, had (1) a greater increase in retroglossal airway size; (2) increased shortening of the mandible-hyoid distance; and (3) greater anterior displacement of the tongue.

Conclusions

These results suggest that smaller soft palate volumes at baseline and greater tongue movement anteriorly with stimulation improve the response to upper airway stimulation.

A rare case of retroperitoneal synovial sarcoma

Management of retroperitoneal soft tissue sarcomas is complex. Treatment is usually multimodal; involving surgery, chemotherapy and radiotherapy.

Systematic approach to musculoskeletal benign tumors

The radiologic workup of musculoskeletal tumors can be both cost-efficient and extremely helpful to the referring clinician if one proceeds in a thoughtful and logical manner. It should be remembered that plain films remain the most reliable imaging method for assessment of both biological activity and probable histologic diagnosis of an osseous lesion. Further investigations are of help to determine the extent of lesion and to help in staging. In order to do this, we have found it useful to include an assessment of 10 determinants in the description of a tumor. If these determinants are accurately described, the correct diagnosis or at least a limited differential diagnosis usually becomes obvious.

Retroperitoneal Sarcomas

BACKGROUND

The evaluation and treatment of retroperitoneal sarcomas are challenging because the tumors are relatively rare and frequently present with advanced disease in an anatomically complex location.

METHODS

We reviewed the literature on experience in the management of retroperitoneal sarcomas, and we present our own experience in the treatment of these tumors.

RESULTS

The identification of prognostic factors other than the adequacy of resection has been inconsistent. Due to a lack of associated symptoms, retroperitoneal sarcomas smaller than 5 cm are rare. Computed tomography is the most useful tool in the evaluation of retroperitoneal tumors. Surgery, radiation therapy, and chemotherapy are treatment options, but the most important factor in the treatment of primary tumors is complete surgical resection. The role of neoadjuvant and adjuvant therapies is not defined and should be considered within the context of clinical trials.

CONCLUSIONS

Early referral of patients with retroperitoneal soft tissue tumors will help to ensure that they will receive the benefits of multidisciplinary evaluation and treatment of their disease and ready access to clinical trials.

The role of ultrasound-guided fine needle aspiration biopsy in musculoskeletal diseases

Ultrasonography (US) is a readily available non-invasive tool useful for the detection of musculoskeletal and soft tissue masses. Although X-Ray is often the first imaging study for evaluating both bone and soft tissue lesions, and magnetic resonance imaging and computed tomography are mandatory in lesions staging, US is increasingly used for the early assessment of musculoskeletal and soft-tissue masses and for guiding procedures and biopsies. Surgical biopsy or fine needle aspiration biopsy (FNAB) is needed to ascertain the nature of any lesion. FNAB is a low cost technique, safer and less traumatic than an open surgical biopsy. Significant complications are rare, mostly related to the site of biopsy. Knowledge of indications, limitations, anatomical and pathological access, adequate technical expertise in US imaging and in intervention skills are the critical factors of the appropriate and safe use of FNAB. By now, the role of FNAB in musculoskeletal diseases is controversial and there is still a heated debate in the scientific community.

Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography

Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive (106)Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively.

Prevalence of a soft-tissue lesion after small head metal-on-metal total hip replacement: 13- to 19-year follow-up study

We investigated the incidence of soft-tissue lesions after small head metal-on-metal total hip replacement (MoM THR). Between December 1993 and May 1999, 149 patients (195 hips) underwent primary cementless MoM THR. During the follow-up period, three patients (five THRs) died and eight patients (14 THRs) were lost to follow-up. We requested that all patients undergo CT evaluation. After exclusion of five patients (six THRs) who had undergone a revision procedure, and 22 (28 THRs) who were unwilling to take part in this study, 111 patients (142 THRs) were evaluated. There were 63 men (88 THRs) and 48 women (54 THRs) with a mean age of 45.7 years (37 to 56) at the time of surgery. The mean follow-up was 15.4 years (13 to 19). A soft-tissue lesion was defined as an abnormal peri-prosthetic collection of fluid, solid lesion or asymmetrical soft-tissue mass. At final follow-up, soft-tissue lesions were found in relation to 28 THRs (19.7%), including 25 solid and three cystic lesions. They were found in 20 men and eight women; 26 lesions were asymptomatic and two were symptomatic. The mean maximal diameter of the soft-tissue lesion was 42.3 mm (17 to 135). The relatively high rate of soft-tissue lesions observed with small head MoM THR remains a concern.

In vitro evaluation of a novel fiducial marker for computed tomography and magnetic resonance imaging of soft tissues in small animals

OBJECTIVE

To construct and optimize a fiducial marker suitable for both CT and MRI.

SAMPLE

Fiducial markers containing serial dilutions of iopamidol mixed with water.

PROCEDURES

IV tubing sets were infused with serial dilutions (0% to 100%; increments of 10%) of iopamidol. Tubing ends were sealed; additional seals were added to create an equilateral triangle. A reference point was created by placing a crimp in 1 side. Markers were fixed to a gelatin soft tissue-attenuating phantom and evaluated by use of CT and MRI. For CT, simple linear regression analysis was used to assess the relationship between the percentage of marker contrast medium and quantitative variables, including marker attenuation, attenuation changes in the phantom, and beam-hardening artifact length. A subjective grading scheme for artifact creation on CT images and marker visibility on MRI images was used. Measurements were obtained by investigators who were unaware of the contents of each marker.

RESULTS

Percentage of contrast medium in each marker was strongly correlated with marker attenuation (r(2) = 0.96), artifact length (r(2) = 0.765), and mean attenuation changes within the phantom (r(2) = 0.826) for CT. Subjective CT scores indicated that concentrations of contrast medium > 50% resulted in excessive artifacts. Markers with concentrations of iopamidol > 50% had poor subjective MRI visibility scores. No artifacts were seen on MRI.

CONCLUSIONS AND CLINICAL RELEVANCE

A marker containing a 10% solution of iodinated contrast medium mixed with water provided ideal contrast for both CT and MRI.

Accuracy of magnetic resonance imaging in planning the osseous resection margins of bony tumours in the proximal femur: based on coronal T1-weighted versus STIR images

OBJECTIVE

Assessment of the extent of tumours using magnetic resonance imaging (MRI) is the basis for bone resection in limb-salvage surgery. We aimed to compare the accuracy of T1-weighted MRI and STIR sequences in measuring the extent of proximal femoral tumours, using the macroscopic specimens as the gold standard for comparison.

MATERIALS AND METHODS

We compared single coronal T1-weighted with STIR sequences in 34 proximal femoral tumours, using bivalved resected macroscopic tumours for comparison. After randomisation, four observers measured longitudinal osseous tumour extent using MRI and specimen photographs on two separate occasions, 3 weeks apart.

RESULTS

There were 25 metastatic tumours, 8 chondrosarcomas and 1 myeloma. Eight patients presented with pathological fractures. The Pearson's correlation coefficient for comparison of T1 with macroscopic tumours was 0.91 (95% confidence interval [CI]: 0.83 to 0.96) for all observers and 0.90 (95% CI: 0.81 to 0.95) for STIR images. This difference was not statistically significant, and T1 and STIR sequence measurements had similar precision and accuracy. Bland-Altman plots showed T1-weighted imaging to be unbiased, whereas STIR sequences were biased and had systematic error. Moreover, STIR measurements overestimated tumour size by 6.4 mm (95% CI: -26.9 to 39.7 mm) and 2 patients were outliers. T1 measurements were closer to the macroscopic measurements with a mean difference of 1.3 mm (95% CI: -28.9 mm to 31.5 mm), with 3 patients falling outside of this. The variance was greater for STIR measurements. This difference between T1 and STIR measurements was statistically significant (p = 0.000003). The intra-observer reliability between separate measurements for MRI and specimen photographs achieved interclass correlation coefficients of 0.97, 0.96 and 0.95 (T1, STIR and macroscopic tumour respectively). T1 had greater interobserver correlation than for STIR and macroscopic tumour measurements (0.88 vs 0.85 and 0.85 respectively). These differences in interclass correlation were not statistically significant.

CONCLUSION

This study has shown T1-weighted MRI sequences to be unbiased compared with STIR sequences at determining intra-osseous tumour extent. STIR overestimates the length of bone tumours. T1 is therefore preferred for pre-operative planning for the resection of bone tumours.

Retroperitoneal sarcoma involving unilateral double ureter: management, treatment and psychological implications

The case of a 45-year-old woman who was admitted to our university hospital for polymenorrhea, weight gain and pain in the left iliac region is reported. An abdominal ultrasound revealed a 9.5 × 5.2-cm, hypoechoic and inhomogeneous mass located on the left side of the pelvis and behind the ovary. The patient underwent surgery. The pelvic mass was firmly anchored to the small intestine, colon, sigma and uterine fundus. After removing the adhesions, double ureters, which had been incorporated in the mass, were observed on the left side. Resection of the unilateral double ureters was necessary in order to remove the entire mass, and thereafter, a left salpingoophorectomy was performed. A histological examination showed a malignant retroperitoneal mass. Termino-terminal ureteral anastomosis with two double-J stents was carried out. Total hysterectomy with preservation of the right adenexum and regional lymphadenectomy was performed. The purpose of this case report is to discuss the physical and psychological implications related to the combination of two rare entities: leiomyosarcoma and a double ureter located within the mass. A literature review on the clinical management and psychological aspects from a female cancer patient's perspective undergoing surgery with the aforementioned disorders will be discussed.

Imaging evaluation of musculoskeletal tumors

In this chapter, we review different imaging modalities, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine scintigraphy, and their application to musculoskeletal neoplasm. Advantages and limitations of each modality are reviewed, and suggestions for imaging approach are provided.

The clinical value of combined use of MR imaging and multi-slice spiral CT in limb salvage surgery for orthopaedic oncology patients: initial experience in nine patients

Background

The purpose of this prospective study was to evaluate the value of the combined use of MR imaging and multi-slice spiral CT for limb salvage surgery in orthopaedic oncology patients.

Patients and methods

Nine consecutive patients with lower/upper limb malignant bone tumours (7 osteosarcomas and 2 chondrosarcomas) were treated with limb-salvaging procedures. Preoperative planning including determination of the osteotomy plane and diameters of the prosthesis was performed basing on the preoperative CT and MR images. The histopathology was performed as golden diagnostic criteria to evaluate the accuracy of CT and MR-based determination for tumour’s boundary.

Results

The tumour extension measured on MRI was consistent with the actual extension (P>0.05, paired Student’s t test), while the extension measured on CT imaging was less than the actual extension. The length, offset and alignment of the affected limb were reconstructed accurately after the operation. An excellent functional outcome was achieved in all patients.

Conclusions

In the present study, MRI was found to be superior to CT for determining the tumour extension, combined use of MRI and CT measurement provided high precision for the fit of the prosthesis and excellent functional results.

Radiography, 99mTc–HDP, and 111In Labeled Vitamin B12 SPECT of Canine Osteosarcoma: A Comparative Study

The objective of this article was to compare radiography, planar bone scintigraphy, and single-photon emission computed tomography (SPECT) to determine the size of osteosarcomas in long bones of dogs. Ten dogs with osteosarcoma in six radii, two humeri, one tibia, and one ulna were evaluated. Macroslides, mediolateral radiographs, planar scintigrams, and sagittal images from SPECT scans were used to obtain measurements. On the scintigraphic images, the edges of the tumor were established using the activity profile imaging tool. The radiographic magnification was factored. The mean percentage of tumor size overestimation was 9.29% on mediolateral radiographs, 5.35% on planar scintigrams, and 33.25% on SPECT images. The correlation coefficient adjusted for sample size was significantly higher (P<0.01) for technetium 99m (99mTc) hydroxyethylene diphosphonate (HDP) (75.5%) and radiography (61.3%) compared with indium 111–vitamin B12 (28.3%). The correlation coefficient for 99mTc–HDP was higher than that obtained for radiographs; however, statistical difference between the two variables was not demonstrated (P>0.05). 99mTc bone scan is a good estimator of intramedullary size of osteosarcoma in long bones when the activity profile tool to determine the margin of the tumor is used.

Radiographic studies in the critical care environment

Critical care patients present with or develop conditions that require imaging with a variety of radiographic methods. Technological advances such as the introduction of digital imaging instead of screen-film radiography have improved image resolution, readability, management, and portability of results while maintaining confidentiality of patient information. Radiographic imaging in the critical care unit is an integral part of patient management. It is imperative that the critical care nurse be cognizant of radiographic studies and thus be able to collaborate with all health care providers in the administration of quality patient care.

Soft-tissue masses and masslike conditions: what does CT add to diagnosis and management?

OBJECTIVE

Although MRI is the technique of choice for evaluating most soft-tissue masses, CT often provides valuable complementary information. Specifically, there are distinguishing CT characteristics that can suggest a specific diagnosis, including the lesion's mineralization pattern, density, pattern of adjacent bone involvement, and degree and pattern of vascularity.

CONCLUSION

This article provides an overview of the CT evaluation of soft-tissue masses, emphasizing a differential diagnosis based on these CT features.

The role of plain radiographs in management of bone metastases

Approximately 50% of patients with cancer will develop skeletal metastases, which often lead to significant pain. When a patient complains of pain, a bone scan and/or plain x-rays are ordered as investigations. X-rays necessitate a 1-cm diameter mass and 50% bone mineral loss at minimum for detection. Up to 40% of lesions will be unidentified by x-rays, presenting false-negative results. Computed tomography (CT) scans can recognize a bony metastatic lesion up to 6 months earlier than an x-ray. However, plain x-rays can also lead to rare false-positive results. We present a case with a false-positive result in a patient with lung cancer.

Advanced modalities for the imaging of sarcoma

There is a diversity of modalities available for the imaging of soft tissue and skeletal sarcomas. However, conventional radiography remains the first line imaging modality in the diagnostic work-up, as it provides superior spatial resolution for the evaluation of bone trabecular detail. This article focuses on the advanced imaging modalities of computer tomography, magnetic resonance imaging, and positron emission tomography in the evaluation of sarcomas.

Diagnostic imaging practice guidelines for musculoskeletal complaints in adults--an evidence-based approach: introduction

PURPOSE

Imaging technology can improve patient outcomes by allowing greater precision in diagnosing and treating patients. However, there is evidence that overuse, underuse, and misuse of imaging services occur. The purpose of this project was to develop evidence-based diagnostic imaging practice guidelines for musculoskeletal complaints for use by doctors of chiropractic and other primary health care professionals.

METHODS

An electronic search of the English and French language literature (phase 1) was conducted on several databases. Cross references, and references provided by clinicians, were also used. Independent assessment of the quality of the citations used to support recommendations in the guidelines was performed using the QUADAS, the AGREE,and the SPREAD evaluation tools. A first draft of a diagnostic imaging practice guideline was produced, using the European Commission's Referral Guidelines for Imaging document as a template. Results were sent to 12 chiropractic specialists for a first external review. A modified Delphi process, including 149 international experts, was used to generate consensus on recommendations for diagnostic imaging studies. The reliability of proposed recommendations was further tested on field chiropractors and on a group of specialists both in chiropractic and in medicine in both Canada and the United States. All recommendations were graded according to the strength of the evidence.

RESULTS

The research procedure resulted in the recommendations for diagnostic imaging guidelines of adult extremity and spine disorders supported by more than 685 primary and secondary citations. High levels of agreement among Delphi panelists were reached for all proposed recommendations. Comments received by specialists were generally very favorable and reflected high levels of agreement with the proposed recommendations, perceived ease of use of guidelines, and implementation feasibility.

CONCLUSIONS

These evidence-based diagnostic imaging practice guidelines are intended to assist chiropractors and other primary care providers in decision making on the appropriate use of diagnostic imaging for specific clinical presentations. In all cases, the guidelines are intended to be used in conjunction with sound clinical judgment and experience. Application of these guidelines should help avoid unnecessary radiographs, increase examination precision,and decrease health care costs without compromising the quality of care. All guidelines are documents to be refined and modified regularly with new information and experience.

Quantitative characterization of metastatic disease in the spine. Part II. Histogram-based analyses

Radiological imaging is essential to the appropriate management of patients with bone metastasis; however, there have been no widely accepted guidelines as to the optimal method for quantifying the potential impact of skeletal lesions or to evaluate response to treatment. The current inability to rapidly quantify the response of bone metastases excludes patients with cancer and bone disease from participating in clinical trials of many new treatments as these studies frequently require patients with so-called measurable disease. Computed tomography (CT) can provide excellent skeletal detail with a sensitivity for the diagnosis of bone metastases. The purpose of this study was to establish an objective method to quantitatively characterize disease in the bony spine using CT-based segmentations. It was hypothesized that histogram analysis of CT vertebral density distributions would enable standardized segmentation of tumor tissue and consequently allow quantification of disease in the metastatic spine. Thirty two healthy vertebral CT scans were first studied to establish a baseline characterization. The histograms of the trabecular centrums were found to be Gaussian distributions (average root-mean-square difference=30 voxel counts), as expected for a uniform material. Intrapatient vertebral level similarity was also observed as the means were not significantly different (p > 0.8). Thus, a patient-specific healthy vertebral body histogram is able to characterize healthy trabecular bone throughout that individual's thoracolumbar spine. Eleven metastatically involved vertebrae were analyzed to determine the characteristics of the lytic and blastic bone voxels relative to the healthy bone. Lytic and blastic tumors were segmented as connected areas with voxel intensities between specified thresholds. The tested thresholds were mu-1.0 sigma, mu - 1.5 sigma, and mu - 2.0 sigma, for lytic and mu + 2.0 sigma, mu+3.0 siema, and mu + 3.5 sigma for blastic tissue where mu and sigma were taken from the Gaussian characterization of a healthy level within the same patient. The ideal lytic and blastic segmentation thresholds were determined to be mu-sigma and mu + 2 sigma, respectively. Using the optimized thresholds to segment tumor tissue, a quantitative characterization of disease is possible to calculate tumor volumes, disease severity, and temporal progression or treatment effect. Our proposed histogram-based method for characterizing spinal metastases shows great potential in extending the quantitative capacity of CT-based radiographic evaluations.

Errors in the MRI evaluation of musculoskeletal tumors and tumorlike lesions

Interpretation of an MRI of a suspected musculoskeletal neoplasm can be extremely difficult. Fifty-six MRIs originally evaluated by outside radiologists were independently evaluated by an expert panel consisting of three specialized musculoskeletal radiologists. The outside reports were then graded based upon accuracy and completeness of the differential diagnosis. We compared the expert opinions with those of the outside radiologists. According to the expert panel, only 30 of the 56 (54%) outside reports listed the most likely diagnosis as such and only 35 (63%) listed it at all. A complete appropriate differential diagnosis was listed in only 22 (39%) of the outside reports. Furthermore, 18 (32%) of the outside reports listed diagnoses judged to be extremely unlikely by the experts. In a subset of 15 patients with images that the expert panel had judged diagnostic of specific entities, only nine of the outside reports listed the correct diagnosis as such and only 10 listed it at all. Furthermore, 11 (73%) of the outside reports listed extremely unlikely possibilities for these diagnostic images. We found a substantial difference between the expert and the outside opinions.

Resection of soft tissue sarcoma of the lower limb after evaluation of vascular invasion with intraoperative intravascular ultrasonography

Background

This study investigated the value of intravascular ultrasonography (IVUS) in the intraoperative assessment of vascular invasion of soft tissue sarcoma.

Methods

In a 4-year interval, of 337 patients with soft tissue sarcoma, 20 patients with tumours of the lower limb in close relation to the neurovascular bundle underwent intraoperative IVUS (20 MHz). Intraoperative findings were correlated with preoperative imaging, histopathological appearance of the resection specimen and patient outcome.

Results

Intraoperative IVUS was technically successful in all 20 patients. It correctly predicted vascular involvement (true positive) in ten of 11 patients who required resection of major vessels. There was one false-negative and one false-positive result. With magnetic resonance imaging, there were ten true-positive and three false-positive scans, and one false-negative diagnosis. IVUS improved the assessment of vascular involvement in four of the 20 patients. Histopathological examination confirmed complete resection (R0) in 18 patients. Mean survival was 37 months, and no local recurrence was observed in these patients.

Conclusion

Vascular infiltration by soft tissue sarcoma can be visualized accurately by IVUS. This may improve intraoperative decisions about vessel resection.

Retroperitoneal sarcomas: Combined-modality treatment approaches

Retroperitoneal sarcomas (RPS) are rare tumors, accounting for approximately 15% of soft tissue sarcomas. Surgical resection of localized tumors with gross and microscopically negative margins remains the standard of care. However, because RPS are frequently large and locally advanced, resections are often incomplete, resulting in local recurrence. Investigators are evaluating combined-modality therapies to improve local control and disease-specific survival. This review outlines current concepts and evolving treatment strategies in the diagnosis, staging, and management of RPS.

Concomitant Ewing sarcoma and acute lymphoblastic leukemia in a 5-year-old girl

Malignancies from the Ewing family of tumors and acute lymphoblastic leukemia (ALL) are not known to be associated with each other. A 5-year-old girl was incidentally found to suffer from acute lymphoblastic leukemia during bone marrow staging for Ewing sarcoma of the radius. The simultaneous presence of two distinct neoplasms was confirmed by RT-PCR, with EWS/FLI1 type 1 rearrangement in the bone tumor and TEL/AML1 rearrangement in the marrow. She was treated with chemotherapy, radiotherapy, and surgery and was in remission of both diseases 31 months after diagnosis.

Bone imaging in metastatic breast cancer

Bone is the most common site to which breast cancer metastasizes. Imaging-by skeletal scintigraphy, plain radiography, computed tomography, or magnetic resonance imaging-is an essential part, and positron emission tomography or single-photon emission computed tomography have a potential of evaluating bone metastases, but no consensus exists as to the best modality for diagnosing the lesion and for assessing its response to treatment. Imaging bone metastases is problematic because the lesions can be osteolytic, osteoblastic, or mixed, and imaging modalities are based on either direct anatomic visualization of the bone or tumor or indirect measurements of bone or tumor metabolism. Although bone metastases can be treated, their response to treatment is considered "unmeasurable" according to existing response criteria. Therefore, the process by which oncologists and radiologists diagnose and monitor the response of bone metastases needs revision, and the current inability to assess the response of bone metastases excludes patients with breast cancer and bone disease from participating in clinical trials of new treatments for breast cancer. In this review of the MEDLINE literature, we discuss the pros and cons of each modality for diagnosing bone metastases and for assessing their response to treatment and we present a practical approach for diagnosis and assessment of bone metastasis.

Evaluation and staging of musculoskeletal neoplasia

Musculoskeletal neoplasia are rare and can present in a highly variable fashion. Maintaining an index of suspicion for the presence of neoplasia is important. A standard approach to evaluation with history, physical, and appropriate imaging studies is mandatory. This information then can be synthesized to properly stage the lesion, which in turn facilitates an appropriate treatment plan. This article discusses the systematic approach to the evaluation and staging of musculoskeletal lesions.