Fast magnetic resonance imaging with contrast for soft tissue sarcoma viability

Optimizing Morbidity in Unplanned Soft Tissue Sarcoma Excisions: Should We Skip the Reconstructive Ladder?

INTRODUCTION

Soft tissue sarcomas (STSs) are rare and diverse primary malignant tumors that comprise approximately 1% of all malignancies. Misdiagnoses and unplanned excisions of STSs are common due to the tumor's rarity, leading to secondary tumor bed excisions (TBEs). Reconstructive outcomes for TBEs remain poorly understood, prompting this study to address the knowledge gap and inform preoperative discussions.

METHODS

This was a retrospective cohort study of patients who underwent STS excisions at a quaternary cancer center. Patients were categorized into mass excision (ME) and TBE groups. Reconstructive approaches were divided into simple (primary closure, complex repair, skin grafts, local flaps) and advanced (pedicled or free flaps). The groups were compared for postoperative outcomes, including complications, recurrence, and death.

RESULTS

When simple reconstructive techniques were used, TBEs exhibited higher rates of overall and major complications, whereas MEs had higher rates of overall and minor complications. Intergroup analysis revealed that with simple reconstruction, rates of overall and major complications were higher in TBEs than in MEs, and rates of minor complications were higher in MEs than in TBEs. Regression analyses revealed that simple reconstruction of TBEs had 90% and 180% higher odds of major complications and reoperation compared to simple reconstruction of MEs ( P < 0.05).

CONCLUSION

TBEs, despite their smaller size, exhibited a heightened susceptibility to overall and major complications, challenging the notion that simpler techniques suffice in these cases. Our findings encourage the consideration of advanced reconstructive techniques for TBEs that may seem amenable to simple reconstructive techniques.

Presurgical Perspective and Posttreatment Evaluation of Soft Tissue Tumors of the Ankle and Foot in Adults

This article discusses soft tissue tumors of the ankle and foot region in adults, including tumors of the joints, and also briefly addresses tumor-simulating lesions. We offer general recommendations and describe specific aspects of common entities in that region, such as typical imaging appearance, therapeutic strategies, and posttherapeutic considerations. Focal masses and diffuse swelling are common in the foot and ankle region; most of them are non-neoplastic. Some of the tumors, such as plantar fibromatosis, tenosynovial giant cell tumor, synovial chondromatosis, or schwannoma, have a very typical appearance on magnetic resonance imaging. Sarcomas are rare among true soft tissue tumors; however, they can be small and well demarcated, may grow slowly, and are often misinterpreted as benign. This is especially true for synovial sarcoma, one of the most common sarcomas in this region. Densely packed tissues in the foot and ankle may hamper determining the tissue of origin. Adherence to diagnostic guidelines and cooperation with tumor centers is crucial including for posttherapeutic surveillance. We also describe typical posttherapeutic changes and complications after surgery, radiation therapy, and chemotherapy, as well as parameters for the detection and exclusion of recurrence of soft tissue tumors of the ankle and foot.

Imaging update on soft tissue sarcoma

Soft tissue sarcomas (STS) are rare tumours presenting as soft tissue lumps. Ultrasound is often the primary modality for the initial assessment, with MRI the mainstay for lesion characterisation. PET/CT along with other emerging MRI sequences are used in certain situations as an adjunct and problem solving tool in STS staging and assessment of disease recurrence. Recent advances include the promise of whole body MRI, hybrid PET/MRI, diffusion weighted imaging, dynamic contrast enhanced MRI and advances in artificial intelligence. This article discusses current concepts in extremity STS imaging and highlights recent advances.

Descriptive analysis of MRI functional changes occurring during reduced dose radiotherapy for myxoid liposarcomas

OBJECTIVES

Myxoid liposarcomas (MLS) show enhanced response to radiotherapy due to their distinctive vascular pattern and therefore could be effectively treated with lower radiation doses. This is a descriptive study to explore the use of functional MRI to identify response in a uniform cohort of MLS patients treated with reduced dose radiotherapy.

METHODS

10 patients with MLS were imaged pre-, during, and post-radiotherapy receiving reduced dose radiotherapy and the response to treatment was histopathologically assessed post-radiotherapy. Apparent diffusion coefficient (ADC), T2* relaxation time, volume transfer constant (Ktrans), initial area under the gadolinium curve over 60 s (IAUGC60) and (Gd) were estimated for a central tumour volume.

RESULTS

All parameters showed large inter- and intrasubject variabilities. Pre-treatment (Gd), IAUGC60 and Ktrans were significantly different between responders and non-responders. Post-radiotherapy reductions from baseline were demonstrated for T2*, (Gd), IAUGC60 and Ktrans for responders. No statistically significant ADC differences were demonstrated between the two response groups. Significantly greater early tumour volume reductions were observed for responders.

CONCLUSIONS

MLS are heterogenous lesions, characterised by a slow gradual contrast-agent uptake. Pre-treatment vascular parameters, early changes to tumour volume, vascular parameters and T2* have potential in identifying response to treatment. The delayed (Gd) is a suitable descriptive parameter, relying simply on T1 measurements. Volume changes precede changes in MLS functionality and could be used to identify early response.

ADVANCES IN KNOWLEDGE

MLS are are characterised by slow gradual contrast-agent uptake. Measurement of the delayed contrast-agent uptake (Gd) is simple to implement and able to discriminate response.

Soft Tissue Sarcoma Follow-up Imaging: Strategies to Distinguish Post-treatment Changes from Recurrence

Soft tissue sarcomas encompass multiple entities with differing recurrence rates and follow-up intervals. The detection of recurrences and their differentiation from post-therapeutic changes is therefore complex, with a central role for the clinical radiologist. This article describes approved recommendations. Prerequisite is a precise knowledge of the current clinical management and surgical techniques. We review recurrence rates and treatment modalities. An adequate imaging technique is paramount, and comparison with previous imaging is highly recommended. We describe time-dependent therapy-related complications on magnetic resonance imaging compared with the spectrum of regular post-therapeutic changes. Early complications such as seromas, hematomas, and infections, late complications such as edema and fibrosis, and inflammatory pseudotumors are elucidated. The appearance of recurrences and radiation-associated sarcomas is contrasted with these changes. This systematic approach in follow-up imaging of soft tissue sarcoma patients will facilitate the differentiation of post-therapeutic changes from recurrences.

WITHDRAWN: Risks and Benefits of Gadolinium-Based Contrast Enhanced MRI

The Publisher regrets that this article is an accidental duplication of an article that has already been published in [Seminars in Ultrasound, CT, and MRI, 41/2 (2020) 170–182], https://dx.doi.org/10.1053/j.sult.2019.12.005. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Evaluation of Soft Tissue Sarcoma Response to Preoperative Chemoradiotherapy Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion. MRI tumor size in the longest diameter (LD) was measured according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines. Pharmacokinetic analyses of DCE-MRI data were performed using the Shutter-Speed model. After only 2 weeks of treatment with sorafenib or after 1 chemotherapy cycle, K^trans (rate constant for plasma/interstitium contrast agent transfer) and its percent change were good early predictors of optimal versus suboptimal pathological response with univariate logistic regression C statistics values of 0.90 and 0.80, respectively, whereas RECIST LD percent change was only a fair predictor (C = 0.72). Post-therapy K^trans, v_e (extravascular and extracellular volume fraction), and k_ep (intravasation rate constant), not RECIST LD, were excellent (C > 0.90) markers of therapy response. Several DCE-MRI parameters before, during, and after therapy showed significant (P < .05) correlations with percent necrosis of resected tumor specimens. In conclusion, absolute values and percent changes of quantitative DCE-MRI parameters provide better early prediction and evaluation of the pathological response of soft tissue sarcoma to preoperative chemoradiotherapy than the conventional measurement of imaging tumor size change.

Molecular Predictors of Radiotherapy Response in Sarcoma

OPINION STATEMENT

Soft-tissue sarcoma is one of the few clinical cancer models in which pre-operative radiotherapy is commonly utilized and in which tumor response to radiotherapy could be assessed. However, clinical and histopathological features of soft-tissue sarcomas are not useful in predicting tumor radiotherapy response. Exploration of predictive markers of sarcoma response to radiotherapy is further confounded by discordance between radiological tumor size reduction, pathological changes, and clinical local recurrence rates. The diversity of disease histology and anatomical origin further influences which type of radiotherapy response (volumetric vs. cytotoxic) would best relate to patient outcome. Advances in molecular biology and understanding of sarcoma biology have recently resulted in the identification of several molecular and imaging predictive markers of radiotherapy response. As the underlying mechanism of radiation-induced cell killing involves the production of DNA damage through the production of oxygen radicals, the most promising biomarkers and imaging markers are related to DNA damage repair genes, hypoxia, and tumor vasculature. As bone and cartilaginous sarcomas are less often treated with radiotherapy, biomarkers of response in these diseases are less examined.

The Role of Dynamic Contrast-Enhanced Magnetic Resonance Imaging Parameters in Head-Neck Tumors

We evaluated dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in various head-neck masses, some of which are very rare tumors whose DCE-MRI have not been published to date. The purpose of this study was to investigate DCE-MRI in the differentiation of benign versus malignant lesions and to evaluate the DCE-MRI parameters most predictive for malignancy. Forty-one head-neck tumors including parotid gland tumors in 41 patients were examined at gadolinium-enhanced dynamic MR imaging. There were 26 malignant and 15 benign tumors. DCE-MR images were obtained between four and six minutes. Time-signal intensity curves (TICs) of the tumors on dynamic MR images were plotted, and then time of peak enhancement ( Tpeak), and enhancement ratios (ER) with different times (such as ER30, ER60, ER90, ER120, ERmax) were also calculated. Data of the benign and malignant group with head-neck masses were compared by Mann-Whitney U-test. The mean values of time to peak ( Tpeak) were found to be significantly shorter for the malignant group than the benign tumors ( P<0.05). The mean enhancement rates of malignant lesions were ER30: 60.62±52.62, ER60: 105.65±56.26, ER90: 113.17±45.83, ER120: 116.59±46.75 and ERmax: 128.56±56.51 whereas the mean enhancement rate of benign lesions were ER30: 67.35±60.78, ER60: 79.79±63.33, ER90: 84.53±64.92, ER120: 88.41±67.07 and ERmax: 112.06±66.48. The mean signal intensity values of the 60th second (ER60) and 90th second (ER90) were significantly different from other values for predicting malignancy ( P<.05). The parameters obtained from the time-signal intensity curve are important in differentiating benign and malignant enhancing lesions in dynamic head-neck MR imaging. DCE-MRI cannot replace standard MR imaging sequences for evaluating head-neck masses, but in addition to routine MR imaging it will improve differentiation between benign and malignant lesions.

The Possible Role of PET Imaging Toward Individualized Management of Bone and Soft Tissue Malignancies

This article presents fluorodeoxyglucose PET/computed tomography for the evaluation of soft tissue sarcomas. Its clinical impact is discussed analyzing all the clinical information provided when applied in different phases of the disease. A special paragraph is dedicated to the use of functional imaging for driving the biopsy.

Multiparametric Assessment of Treatment Response in High-Grade Soft-Tissue Sarcomas with Anatomic and Functional MR Imaging Sequences

PURPOSE

To determine the added value of quantitative diffusion-weighted and dynamic contrast material-enhanced imaging to conventional magnetic resonance (MR) imaging for assessment of the response of soft-tissue sarcomas to neoadjuvant therapy.

MATERIALS AND METHODS

MR imaging examinations in 23 patients with soft-tissue sarcomas who had undergone neoadjuvant therapy were reviewed by two readers during three sessions: conventional imaging (T1-weighted, fluid-sensitive, static postcontrast T1-weighted), conventional with diffusion-weighted imaging, and conventional with diffusion-weighted and dynamic contrast-enhanced imaging. For each session, readers recorded imaging features and determined treatment response. Interobserver agreement was assessed and receiver operating characteristic analysis was performed to evaluate the accuracy of each session for determining response by using results of the histologic analysis as the reference standard. Good response was defined as less than or equal to 5% residual viable tumor.

RESULTS

Of the 23 sarcomas, four (17.4%) showed good histologic response (three of four with >95% granulation tissue and <5% necrosis, one of four with 95% necrosis and <5% viable tumor) and 19 (82.6%) showed poor response (viable tumor range, 10%-100%). Interobserver agreement was substantial or excellent for imaging features in all sequences (k = 0.789-1.000). Receiver operating characteristic analysis showed an increase in diagnostic performance with the addition of diffusion-weighted and dynamic contrast-enhanced MR imaging for prediction of response compared with that for conventional imaging alone (areas under the curve, 0.500, 0.676, 0.821 [reader 1] and 0.506, 0.704, 0.833 [reader 2], respectively).

CONCLUSION

Adding functional sequences to the conventional MR imaging protocol increases the sensitivity of MR imaging for determining treatment response in soft-tissue sarcomas.

Unplanned excision of soft-tissue sarcomas: current concepts for management and prognosis

➤ Biopsy, staging, preoperative imaging and planning, as well as surgical treatment of soft-tissue sarcomas, are best carried out in specialized sarcoma centers, with the support of a multidisciplinary tumor board.➤ Tumor bed excision is recommended after most unplanned excisions, with a goal of obtaining complete tumor removal with an appropriately wide margin of resection.➤ The surgical resection area tends to be more extensive during tumor bed excision than during primary resection because of the need to resect potential areas of contamination, resulting in the need for more reconstructive procedures (flaps and skin grafts) and wider radiation fields.➤ Unplanned excisions are associated with an increased rate of local recurrence related to residual disease and positive margins after tumor bed excision, a deep location, and certain histologic subtypes, such as malignant peripheral nerve sheath tumor, myxofibrosarcoma, and dermatofibrosarcoma protuberans.➤ While adjuvant radiation therapy has not been found to mitigate the risk of local recurrence in unplanned excisions, it is generally utilized in the treatment of unplanned excisions as it is in the treatment of primary soft-tissue sarcomas.➤ Given the surgical and oncologic sequelae of unplanned excisions, prevention through the diffusion of concepts by means of provider education on how to approach soft-tissue masses, which can be potential soft-tissue sarcomas, is the best strategy.

Multidisciplinary management of soft tissue sarcoma

Soft tissue sarcoma is a rare malignancy, with approximately 11,000 cases per year encountered in the United States. It is primarily encountered in adults but can affect patients of any age. There are many histologic subtypes and the malignancy can be low or high grade. Appropriate staging work up includes a physical exam, advanced imaging, and a carefully planned biopsy. This information is then used to guide the discussion of definitive treatment of the tumor which typically involves surgical resection with a negative margin in addition to neoadjuvant or adjuvant external beam radiation. Advances in imaging and radiation therapy have made limb salvage surgery the standard of care, with local control rates greater than 90% in most modern series. Currently, the role of chemotherapy is not well defined and this treatment is typically reserved for patients with metastatic or recurrent disease and for certain histologic subtypes. The goal of this paper is to review the current state of the art in multidisciplinary management of soft tissue sarcoma.

Technical innovation in dynamic contrast-enhanced magnetic resonance imaging of musculoskeletal tumors: an MR angiographic sequence using a sparse k-space sampling strategy

OBJECTIVE

We demonstrate the clinical use of an MR angiography sequence performed with sparse k-space sampling (MRA), as a method for dynamic contrast-enhanced (DCE)-MRI, and apply it to the assessment of sarcomas for treatment response.

MATERIALS AND METHODS

Three subjects with sarcomas (2 with osteosarcoma, 1 with high-grade soft tissue sarcomas) underwent MRI after neoadjuvant therapy/prior to surgery, with conventional MRI (T1-weighted, fluid-sensitive, static post-contrast T1-weighted sequences) and DCE-MRI (MRA, time resolution = 7-10 s, TR/TE 2.4/0.9 ms, FOV 40 cm(2)). Images were reviewed by two observers in consensus who recorded image quality (1 = diagnostic, no significant artifacts, 2 = diagnostic, <25 % artifacts, 3 = nondiagnostic) and contrast enhancement characteristics by static MRI (presence/absence of contrast enhancement, percentage of enhancement) and DCE-MRI (presence/absence of arterial enhancement with time-intensity curves). Results were compared with histological response (defined as <5 % viable tumor [soft tissue sarcoma] or <10 % [bone sarcoma] following resection).

RESULTS

Diagnostic quality for all conventional and DCE-MRI sequences was rated as 1. In 2 of the 3 sarcomas, there was good histological response (≤5 % viable tumor); in 1 there was poor response (50 % viable tumor). By static post-contrast T1-weighted sequences, there was enhancement in all sarcomas, regardless of response (up to >75 % with good response, >75 % with poor response). DCE-MRI findings were concordant with histological response (arterial enhancement with poor response, no arterial enhancement with good response).

CONCLUSION

Unlike conventional DCE-MRI sequences, an MRA sequence with sparse k-space sampling is easily integrated into a routine musculoskeletal tumor MRI protocol, with high diagnostic quality. In this preliminary work, tumor enhancement characteristics by DCE-MRI were used to assess treatment response.

Diffusion-weighted MRI for detection and differentiation of musculoskeletal tumorous and tumor-like lesions in pediatric patients

BACKGROUND

MRI is the diagnostic mainstay for detection and differentiation of musculoskeletal tumors. However, a projection regarding the biological dignity of lesions based on standard MRI sequences remains difficult and uncertain. This study was undertaken to analyse whether diffusion-weighted MRI (DWI) can distinguish between benign and malignant musculoskeletal tumorous and tumor-like lesions in pediatric patients.

METHODS

MR examinations of 44 consecutive pediatric patients (26 girls, mean age 11±6 years) including standard sequences and DWI (b=50/800 s/mm(2)) at 1.5 or 3 Tesla were retrospectively evaluated. The study group contained 10 patients with non-treated malignant tumors and 34 patients with benign lesions. Size, relative signal intensity and apparent diffusion coefficient (ADC, unit ×10(-3) mm(2)/s) were determined in one lesion per patient.

RESULTS

Mean ADC was 0.78±0.45×10(-3) mm(2)/s in patients with malignant tumors and 1.71±0.75 ×10(-3) mm(2)/s in patients with benign lesions (P<0.001). Relative operating characteristics (ROC) analysis showed a sensitivity of 90% and a specificity of 91% for malignancy, based on an ADC cut-off value of ≤1.03. On logistic regression, mean ADC and lesion size accounted for 62% of variability in benign vs. malignant tumors. For malignant tumors, the signal intensity ratio was higher on DWI than on T1w post-contrast images (P<0.002). Two cases of local tumor recurrence were diagnosed by DWI only.

CONCLUSIONS

DWI shows promising results for determination of biological dignity in musculoskeletal tumors. Mean ADC ≤1.03×10(-3) mm(2)/s is a strong indicator of malignancy at the first diagnosis. The use of DWI for early diagnosis of tumor recurrence in comparison with standard MRI sequences should be evaluated in prospective studies.

Not all sarcomas developed in irradiated tissue are necessarily radiation-induced--spectrum of disease and treatment characteristics

BACKGROUND

Sarcomas in irradiated tissue (SITs) are often considered with second cancers, although they usually present distinct dose-response, genetic and clinical patterns. The contribution of radiation in SIT development is likely, but remains unproven in many cases.

MATERIALS AND METHODS

We reviewed the literature for published data on SITs.

RESULTS

SITs incidence ranged between 0.03% and 0.2%. Median latency was 15 years. Angiosarcoma was the second most common subtype after undifferentiated sarcomas of malignant fibrous histiocytoma (MFH). C-Myc overexpression can be used to identify radiation-induced angiosarcoma, and a recently described transcriptomic signature of genes involved in chronic oxidative stress and mitochondrial dysfunction may indicate radiation causality. Osteosarcomas were often associated with genetic predisposition. Five-year survival rates rarely exceeded 30% because the therapeutic possibilities were often limited by the first cancer. Chemotherapy response may differ from that of de novo sarcomas.

CONCLUSION

SITs present different characteristics from non-sarcomatoid second cancers. Reporting of SIT cases and the establishment of tissue and serum banks is necessary to better understand and validate the recently discovered radiation signature.

Accuracy of core-needle biopsy after contrast-enhanced ultrasound in soft-tissue tumours

OBJECTIVE

Percutaneous biopsies are gaining acceptance in the diagnosis of soft-tissue tumours. Sampling in the most representative area is not easy in sarcomas of huge dimension. We hypothesised that ultrasound (US) contrast medium could identify the representative area for focus core-needle biopsy (CNB) METHODS: This is a retrospective cohort series of 115 soft-tissue masses treated from January 2007 to November 2008. Accuracy of US-guided CNB after contrast-enhanced US (CEUS) was determined by comparing the histology of the biopsy with the definitive diagnosis in 105 surgically excised samples (42 benign, 63 malignant) and with the expected outcome in the remaining ten malignant cases not surgically treated. A myxoid component was present in 21 sarcomas (34.4%).

RESULTS

Of samples, 94.8% were adequate for diagnosis with 97.1% sensitivity and 92.5% specificity. Sensitivity and specificity in specific histopathological subgroupings were 100%, and in grading definition they were 100% and 96.8%.

DISCUSSION

US-guided CNB is safe and effective. US contrast medium depicts tumour vascular supply and identifies the representative area(s) for sampling. Sensitivity and specificity are also high in subgrouping and grading, including myxoid types. Discussion about biopsy is part of the essential multidisciplinary strategy for these tumours.

Soft tissue tumours: imaging strategy

Vascular tumours and malformations, fibrous and fibrohistiocytic tumours and pseudotumours are the most common benign soft-tissue masses observed in children, and can be treated conservatively. Rhabdomyosarcomas are the most frequent malignant tumours, accounting for about half of soft tissue sarcomas. A child referred for a soft-tissue mass should ideally be managed by a multidisciplinary team and primary excision should be proscribed until a definite diagnosis has been established. Clinical examination, conventional radiography and US with Doppler represent the first-line examinations and are sometimes sufficient to make a diagnosis. In all other situations, MRI is mandatory to establish the aggressiveness and extension of the tumour. This technique provides the relevant data to guide the decision regarding tissue sampling.

Pediatric soft-tissue tumors and pseudo-tumors: MR imaging features with pathologic correlation: part 1. Imaging approach, pseudotumors, vascular lesions, and adipocytic tumors

A wide spectrum of entities may give rise to soft-tissue masses in children, including benign and malignant tumors, pseudotumors, and both neoplastic and nonneoplastic vascular lesions. Because of its excellent tissue contrast, multiplanar capability, and lack of ionizing radiation, magnetic resonance (MR) imaging has become the modality of choice in the evaluation of deep and large soft-tissue masses in children. In the vast majority of cases, however, accurate interpretation of the MR imaging findings requires correlation with the clinical findings. For example, in most posttraumatic and inflammatory pseudotumors, the clinical history is fundamental to establishing the diagnosis. In the evaluation of periarticular cysts, the location of the mass and its relationship to a joint are crucial for diagnosis, whereas in the evaluation of vascular lesions, including hemangiomas and vascular malformations, clinical findings combined with MR imaging findings are needed for accurate diagnosis in most cases. The identification of fat within adipocytic tumors is useful, but tissue biopsy may be required for final diagnosis. Nevertheless, MR imaging is useful in determining the origin and character of pediatric soft-tissue masses, defining their extent and their relationship to adjacent structures, and performing posttherapy follow-up.

Soft-tissue sarcoma

Soft-tissue sarcomas are rare malignancies of mesodermal origin. Common sites of involvement include the extremities, trunk, retroperitoneum, and the head and neck. Soft-tissue sarcomas of the extremities and pelvis are the most relevant to the orthopaedic surgeon. The patient with extremity soft-tissue sarcoma typically presents with a painless, enlarging mass. Advanced imaging techniques and biopsy, which are best done at tertiary referral centers, usually confirm the diagnosis. Factors such as sarcoma size, location, grade, histologic subtype, and stage, as well as patient age and comorbidities, determine the specific approach to management and patient outcome. Limb-sparing surgical resection is the mainstay of treatment. Radiation is used for unresectable tumors and as a neoadjuvant or an adjuvant to resection. The use of chemotherapy is controversial, and no standardized protocol has been established.

Clinical problems after initial unplanned resection of sarcoma

OBJECTIVE

Unplanned resection of a sarcoma is often chosen in the early phase by general physicians without any imaging scrutiny. The present study aimed to highlight the clinical problems associated with unplanned resection of sarcomas.

METHODS

Thirty-eight patients who underwent unplanned resection of a sarcoma and additional treatment were examined. The definite histological grading was high in 31 patients and low in 7 patients.

RESULTS

The tumors were located in the depth of the subfascia in 13 patients. The maximal tumor sizes exceeded 5 cm in 16 patients. Preoperative MRI was only performed in six patients. The previous surgical margins were intralesional in 20 patients and marginal in 18 patients. Inappropriate transverse skin incisions were found in 21 patients. Extensive hematoma at the initial surgical site was seen in five patients. Thirty-three patients accepted additional wide resection due to the insufficient removal of malignancy. During an average follow-up of 42.7 months, seven patients died of lung and brain metastases.

CONCLUSIONS

On excision of any soft tissue tumor, surgeons should be aware of the potential risk for erroneous management of malignancy. If not, careless surgery may render the treatment protocol complicated and require excessive additional tissue resection with poor function and prognosis. Appropriate salvage treatment may have a significant role to play after unplanned resection of the sarcoma.

Musculoskeletal tumours: preliminary experience with perfusion MRI

PURPOSE

Our study aimed to assess the role of magnetic resonance imaging (MRI) in the characterisation of musculoskeletal tumours and to identify specific perfusion patterns for the different tumours.

MATERIALS AND METHODS

Between January 2003 and September 2005, we evaluated the conventional and perfusion MRIs of 39 patients with musculoskeletal tumours. Dynamic MRI was performed with a 1.5-T and 1.0-T MRI unit before and after the intravenous administration of contrast material, using dedicated phased-array coils appropriate for the region to be studied and fast and ultrafast consecutive sequences. Postprocessing was done on an independent workstation (Advantage Windows, GE Medical System), with Functool (GE) software, which allowed a quantitative evaluation of enhancement as a function of time. The results were compared with the histopathological diagnoses obtained by biopsy or surgery.

RESULTS

The lesions identified in the 39 patients included 23 soft tissue tumours (12 benign, 11 malignant) and 16 bone tumours (ten benign, six malignant). Comparing the time-intensity diagrams of lesions of the same histological type, we found typical enhancement patterns for some bone tumours only, especially for bone, cartilaginous, fibrohistiocytic and pseudoinflammatory lesions. No typical enhancement pattern could be detected for any of the histological types of soft tissue tumour. Analysis of the slope of the time-intensity curves has a sensitivity and specificity of 64%-58% for soft tissue tumours and 86%-67% for bone tumours in determining the biological aggressiveness of the lesions.

CONCLUSIONS

Perfusion MRI had moderate sensitivity and specificity in the differential diagnosis between lesions with high or low biological activity. Only in a few cases was it possible to find some correlation between perfusion patterns and lesion histology. The slope values should therefore be used in combination with conventional spin-echo images and other imaging and clinical data in order to narrow the field of the possible differential diagnoses and reliably predict the nature of the lesion.

Focus on the tumour periphery in MRI evaluation of soft tissue sarcoma: infiltrative growth signifies poor prognosis

Purpose. Infiltrative microscopical peripheral growth of soft tissue sarcomas (STS) has been shown to be of prognostic importance and preoperative risk stratification could individualize neoadjuvant treatment. Patients and methods. We assessed peripheral tumour growth pattern on preoperative MRI from 78 STS. The findings were correlated to histopathology and to outcome. Results. The MRI-based peripheral tumour growth pattern was classified as pushing in 34 tumours, focally infiltrative in 25, and diffusely infiltrative in 19. All tumours with diffuse infiltration on MRI also showed microscopical infiltration, whereas MRI failed to identify infiltration in two-thirds of the microscopically infiltrative tumours. Diffusely infiltrative growth on MRI gave a 2.5 times increased risk of metastases (P = .01) and a 3.7 times higher risk of local recurrence (P = .02). Discussion. Based on this observation we suggest that MRI evaluation of STS should focus on the peripheral tumour growth pattern since it adds prognostic information of value for decisions on neoadjuvant therapies.

Quality of reporting of orthopaedic diagnostic accuracy studies is suboptimal

Complete and accurate reporting of diagnostic research are essential to assess the validity of its results. To improve the quality of reporting of diagnostic accuracy studies, the Standards for Reporting of Diagnostic Accuracy (STARD) steering committee has developed a checklist of 25 items. We asked whether the quality of reporting of diagnostic accuracy studies published in three major orthopaedic journals (Clinical Orthopaedics and Related Research, Journal of Bone and Joint Surgery British Volume, and Journal of Bone and Joint Surgery American Volume) would be similar across levels of study, journals, and years of publication, and would be similar to other subspecialty journals. We identified 37 articles from 2002-2004 diagnostic accuracy studies and applied the STARD checklist and scoring system. The scores ranged from 6.6 to 21.4 with a mean of 15 +/- 3.3. Only 38% of the articles (14 of 37) reported more than 2/3 of the items, and the majority failed to report nine specific items. The mean STARD scores were similar between the studies with different levels of evidence, across the three journals, and across the three years of publication. They were similar to scores for other subspecialty journals. The current standards of reporting of diagnostic accuracy studies in orthopaedic journals are suboptimal.

Imaging and diagnostic strategy of soft tissue tumors in children

The diagnosis of a soft tissue mass in children is a common clinical situation. Most of the lesions are benign and can be treated conservatively or by non-mutilating surgery. Nevertheless, the possibility of a malignant soft tissue tumor must be systematically considered. The most frequent benign soft tissue lesions in children are vascular lesions, fibrous and fibrohistiocytic tumors and pseudotumors, whereas rhabdomyosarcomas account for 50% of all soft tissue sarcomas. A child presenting an atypical soft tissue mass should be managed by a multidisciplinary centre, and primary resection must be proscribed until a definite diagnosis has been established. The role of imaging is essential either to confirm the benign nature of the mass or to give arguments to perform a diagnostic biopsy. Clinical examination, conventional radiography and ultrasound with Doppler represent the first-line examinations and are sometimes sufficient to assess a diagnosis. In all other situations, MRI is mandatory to establish the probable nature of the lesion and to assess local extension.

Imaging and Response in Soft Tissue Sarcomas

Conventional CT and MRI scans provide exquisite anatomic detail of soft tissue sarcomas but fall short of estimating the degree of tumor viability within a sarcomatous mass. Functional imaging methods that measure biologic properties within sarcomas may be better able to determine true tumor responses to chemotherapy or radiotherapy. Many different approaches to measure biologic processes have been taken and are discussed, but positron emission tomography (PET) is currently the most quantitative and developed. A response in tumor glucose uptake, determined by PET, has been shown to correlate with improved clinical outcomes in high-grade extremity soft tissue sarcomas and gastrointestinal stromal tumors. Functional imaging of soft tissue sarcomas may prove to be useful clinically, therefore further investigation is warranted.

Doppler US with perfusion software and contrast medium injection in the early evaluation of isolated limb perfusion of limb sarcomas: prospective study of 49 cases

BACKGROUND

The aim of this study was to prospectively evaluate the use of Doppler ultrasonography with perfusion software and contrast agent injection (DUPC) during isolated limb perfusion (ILP) with high-dose chemotherapy and TNF-alpha(biochemotherapy) in patients with locally advanced extremity soft tissue sarcoma (STS).

PATIENTS AND METHODS

Fifty-two patients were prospectively included in this monocentric imaging trial. Three were excluded because the study was incomplete in two patients and one tumour did not exhibit any contrast uptake. DUPC was performed before ILP and on days 1, 7, 15, 30 and 60 after ILP. A total of 292 DUPC were performed on 55 target lesions in 49 evaluable patients. The percentage of contrast uptake was evaluated at each tumour site by two radiologists. The criterion tested was a decrease of more than 50% in intra-tumour contrast uptake compared to the pre-ILP examination. Results were compared with both MRI and histological analysis after resection of residual disease.

RESULTS

According to MRI and the histological analysis, 25 (51%) patients were good responders (no difference between the four treatment arms) with tumour necrosis exceeding 90% and 24 (49%) were poor responders. As of day +1, the accuracy of DUPC in predicting tumour response was 82% (18/25 good responders and 22/24 poor responders) increasing to 91% at day +7, 95% at day +15 and 96% at day +30. At day +15, DUPC was predictive of a good response in 100% of the cases.

CONCLUSION

DUPC is a simple technique, allowing early prediction of tumour response after ILP. A new treatment planning scheme can be proposed based on the results of this study.

The MR imaging appearances and natural history of seromas following excision of soft tissue tumours

Fluid collections (seromas) may accumulate at the site of surgery following excision of musculoskeletal soft tissue tumours. The aim of this retrospective study was to review the magnetic resonance (MR) imaging features of postoperative seromas identifying changes over time on follow-up scans. A total of 170 MR scans from 80 patients were reviewed showing one or more seromas. All patients had undergone previous surgery for a musculoskeletal soft tissue tumour. The typical MR appearances of a seroma were shown to be a well-defined oval or rounded (54%) soft tissue mass, arising at the site of previous surgery, with a thin, dark pseudocapsule, surrounding soft tissue oedema (80%), homogeneous contents that are hypointense (relative to adjacent muscle) on T1-weighted images (74%) and hyperintense on T2-weighted and STIR images (79%). Approximately one-quarter of cases revealed atypical features including hyperintense contents on T1-weighted (26%) and/or heterogeneous contents on T2-weighted images (21%), reflecting the breakdown of blood products and organization of the fluid collection. A distinctive fine feathery pattern arising from the inner surface of the seroma or from septations was identified in 10% of cases. In those patients who underwent one or more follow-up scans, the volume of the seromas decreased in 66% cases, remained unchanged in 15% and increased in 19%. Seromas are not an uncommon finding (<10% of cases) following surgery for a soft tissue tumour. The majority of cases show the typical MR features of a fluid collection. The pitfalls in differentiating an atypical seroma from a recurrent soft tissue sarcoma are discussed.

MR imaging in the assessment of residual tumour following inadequate primary excision of soft tissue sarcomas

The purpose of this retrospective study was twofold: firstly, to assess the ability of MR imaging in confirming/excluding the presence of residual tumour following inadequate primary excision of soft tissue sarcomas; and secondly, to assess the accuracy of the original radiologists report as compared with a retrospective review of the scan hard copy in confirming/excluding. A total of 111 cases were identified that fulfilled the inclusion criteria of inadequate primary surgery followed by a MR scan and subsequent wide re-excision of the surgical field. The gold standard for the assessment of the MR imaging studies was histological examination of the re-excision specimens. Histological examination revealed residual tumour in 63 (56.7%) cases. In 48 cases the residual tumour was classified macroscopic (maximum diameter >10 mm) and 15 cases microscopic (maximum diameter </=10 mm). The original radiologists reports failed to indicate the presence or absence of tumour in 7 (6.3%) cases. In the remaining 104 cases the diagnostic performance of MR imaging gave a sensitivity of 0.64, specificity of 0.93, positive predictive value of 0.93 and negative predictive value of 0.67. In 12 of the 21 false-negative scans the residual tumour was microscopic. Subjective assessment of the radiologist's reports indicated that the proportion of equivocal reports was much higher in both the false-negative and false-positive groups as compared with the true groups. An unblinded retrospective review of the scan hard copies only differed from the original radiologists report in 8 (7.2%) cases. Contrast-enhanced sequences were not routinely obtained in this series. The results suggest that the poor negative predictive value can be attributed more to limitations of the MR scan and not to failures in observation or interpretation by the radiologists. Despite the low negative predictive value, MR imaging remains useful in planning the re-excision surgery by identifying the site and extent of the original operation and size of major residual tumour.

Dynamic contrast-enhanced MR imaging in monitoring response to isolated limb perfusion in high-grade soft tissue sarcoma: initial results

The objective of this study was to evaluate whether dynamic contrast-enhanced MR imaging can determine tumor response and localize residual viable tumor after isolated limb perfusion (ILP) chemotherapy in soft tissue tumors. Twelve consecutive patients, with histologically proven high-grade soft tissue sarcoma, prospectively underwent non-enhanced MR and dynamic contrast-enhanced MR imaging before and after ILP. Tumor volume was measured on non-enhanced MR images. The temporal change of signal intensity in a region of interest on dynamic contrast-enhanced MR images was plotted against time. Start, pattern, and progression of enhancement were recorded. Histopathologic response was defined as complete response if no residual viable tumor was present, partial remission if <50% viable tumor was present, and no change if > or =50% viable tumor was present in the resection specimen. Resected specimens for correlation with histopathology were available for 10 patients; 5 patients had partial remission and 5 had no change. Volume measurements correctly predicted tumor response in 6 of 10 patients. Dynamic contrast-enhanced MR correctly predicted tumor response in 8 of 10 patients. Early rapidly progressive enhancement correlated histologically with residual viable tumor. Late and gradual, or absence of enhancement, was associated with necrosis, predominantly centrally located, or granulation tissue. These preliminary results show that dynamic contrast-enhanced MR imaging offers potential for non-invasive monitoring of response to isolated limb perfusion in soft tissue sarcomas due to identification of residual areas of viable tumor and subsequently may provide clinically useful information with regards to timing and planning of additional surgery. Further prospective studies in a larger patient population is warranted.