Post-operative imaging of soft tissue sarcomas

Outcomes and complications of postoperative seroma cavities following soft-tissue sarcoma resection

Introduction

Seroma development is a known complication following extremity and trunk soft-tissue sarcoma (STS) resection. The purpose of this study is to evaluate and characterize seroma outcomes and the development of associated complications.

Methods

A retrospective review of 123 patients who developed postoperative seromas following STS resection at a single institution was performed. Various patient and surgical factors were analyzed to determine their effect on overall seroma outcomes.

Results

77/123 seromas (62.6%) were uncomplicated, 30/123 (24.4%) developed infection, and 16/123 (13.0%) were symptomatic and required aspiration or drainage for symptom relief at an average of 12.2 months postoperatively. 65/123 (52.8%) seromas resolved spontaneously at an average time of 12.41 months. Seromas in the lower extremity (p=0.028), surgical resection volume >864 cm3, (p=<0.001) and initial seroma volume >42 cm3 (p=<0.001) increased the likelihood of infection. 90% of infected seromas developed the infection within the first three months following initial resection. No seromas which were aspirated or drained ultimately developed an infection following these procedures, though 50% recurred.

Discussion

Most seromas following STS resection are uncomplicated and do not require intervention, though a large resection cavity >864 cm3 and a large seroma volume >42 cm3 are risk factors for complications.

Diagnosis of Local Recurrence of Malignant Soft Tissue Tumors after Reconstructive Surgery on MRI

PURPOSE

Magnetic resonance imaging (MRI) is useful in the diagnosis of local recurrence, but few studies have explored recurrence in MRI in patients after reconstructive surgery. The purpose of this study was to analyze MRI findings of locoregional recurrence following reconstructive surgery after malignant soft tissue tumor resection.

METHOD

Fifty-three postoperative MRIs from 37 patients who underwent reconstructive surgery after malignant soft tissue tumor resection were retrospectively reviewed. A total of 76 enhancing lesions, including 40 locoregional recurrences and 36 postoperative changes, were analyzed regarding morphology (location on the transplanted tissue, border, and shape) and the signals on T1- and T2-weighted imaging (T1WI, T2WI), fat-suppressed (FS) T2WI, and contrast-enhanced FS T1WI. Diffusion-weighted imaging with an apparent diffusion coefficient was assessed. A chi-squared test and Fisher's exact test were used for statistical analysis.

RESULTS

The most common site of recurrent tumors and postoperative changes was the peripheral margin on transplanted tissue (63% and 61%, respectively p = 0.907). Recurrent tumors commonly appeared with well-defined borders (75%) as well as nodular appearance (98%), hyperintensity on T2WI (85%) and FS-T2WI (95%), isointensity on T1WI (65%), impeded water diffusion (55%), and intense (50%) or moderate (45%) enhancement. Postoperative changes showed ill-defined borders (75%), nodular appearance (56%), facilitated water diffusion (69%), and moderate (86%) enhancement, which were significantly different from those of recurrent tumors (p ≤ 0.020).

CONCLUSIONS

Common and partitioning MRI features of locoregional recurrence were well-defined borders, nodular shape, impeded water diffusion, and intense enhancement. Peripheral margins on transplanted tissue were common sites in both recurrent tumors and postoperative changes.

Presurgical Perspective and Postsurgical Evaluation of the Diabetic Foot

Management of the diabetic foot is complex and challenging, requiring a multidisciplinary approach. Imaging plays an important role in the decision-making process regarding surgery. This article discusses the presurgical perspective and postsurgical evaluation of the diabetic foot.

Does the primary soft-tissue sarcoma configuration predict configuration of recurrent tumors on magnetic resonance imaging?

BACKGROUND

Soft-tissue sarcomas (STS) are rare malignancies of the soft tissue.

PURPOSE

To assess whether the magnetic resonance imaging (MRI) configuration of primary STS can predict the configuration of a recurring tumor and whether the MRI configuration of multiple recurrences differs in one and the same patient.

MATERIAL AND METHODS

Thirty-nine patients with histologically proven recurrent STS were included in this retrospective study and underwent pre- and post-treatment MRI. Three main configurations of primary and recurrent tumors were identified: polycyclic/multilobulated; ovoid/nodular; and streaky.

RESULTS

Sixty recurrent lesions were detected: 34 ovoid/nodular; 15 polycyclic/multilobulated; and 11 streaky. Five recurrences were multifocal and eight were bifocal. Of 39 patients, 28 (71.8%) presented one recurrence within the MRI follow-up period (P = 0.006); in 10 patients (25.6%), up to three different configurations of recurring STS were identified in one patient. Recurrences of polycyclic/multilobulated primaries were mostly ovoid/nodular (48%; P = 0.003) or polycyclic/multilobulated (37%; P = 0.014), and recurring ovoid/nodular STS significantly most often showed the same configuration as the primary tumor (85%; P < 0.001). Primary STS with a streaky configuration recurred in all three configurations in roughly equal proportions. Homogeneity/heterogeneity and tumor borders are significantly associated with the configuration of recurrences.

CONCLUSION

Primary STS configuration may help predict recurrent tumor configuration when the primary STS had a polycyclic/multilobulated or ovoid/nodular configuration. However, recurrent STS configuration can also differ from primary STS configuration, especially when the primary STS had a streaky configuration, rendering recurrent STS difficult to predict. Different configurations of recurrent STS in one and the same patient are common.

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.

Pelvic bone tumor resection: post-operative imaging

The anatomic extent of a pelvic bone tumor and the need for reconstruction dictate the type of pelvic resection (limb salvage pelvic resection or amputation). If a pelvic bone tumor resection involves two or more critical anatomic structures (the sciatic nerve, femoral neurovascular bundle or the hip joint), then reasonable functional recovery after limb salvage is less likely and amputation should be considered. Both limb salvage and amputation approaches to the pelvis are technically arduous surgeries with significant associated morbidity and complications. As such, imaging plays an important role in the post-operative management of patients who have undergone pelvic bone tumor resection. In this article, we will review optimal imaging techniques as well as the expected post-operative appearance after pelvic bone tumor resection and important complications including infection, tumor recurrence, and complications related to complex soft tissue and osseous reconstruction.

Follow-up Strategies for Primary Extremity Soft-tissue Sarcoma in Adults: A Systematic Review of the Published Literature

AIM

Follow-up strategies for primary extremity soft-tissue sarcomas (eSTS) in adults were evaluated in a systematic review of the published literature.

MATERIAL AND METHODS

The published literature was reviewed using PubMed. Of 136,646 studies published between 1985 and 2019, 78 original articles met the inclusion criteria. Articles were selected on the basis of the PRISMA guidelines. The selected articles were then cross-searched to identify further publications. August 1, 2019 was used as the concluding date of publication.

RESULTS

A variety of follow-up schedules have been reported in recently published literature. Two official guidelines have been approved by international societies. The guidelines distinguish between high- and low-grade STS, but mention a wide range of follow-up intervals. Established tools of follow-up include computed tomograph, X-rays of the chest, and magnetic resonance imaging of the primary tumor site in addition to clinical observation and physical examination.

CONCLUSION

Further research will be needed to establish evidence-based guidelines and schedules for follow-up strategies in patients with eSTS.

The importance of diffusion apparent diffusion coefficient values in the evaluation of soft tissue sarcomas after treatment

Purpose

In our study, we aimed to show the efficiency of diffusion-weighted images at different b-values and apparent diffusion coefficient (ADC) values in the differentiation of recurrent tumours from post-treatment tissue changes.

Material and methods

The conventional and diffusion magnetic resonance images (MRIs) of 42 patients operated for soft tissue sarcomas between June 2012 and March 2015 followed up with MRIs that were evaluated by 2 radiologists retrospectively. Diffusion MRIs were acquired at 4 different b-values (50, 400, 800, 1000 s/mm²). The lesions were classified according to conventional MRI findings as post-treatment changes and recurrent tumours.

Results

When the patient group with recurrent tumours was compared with the patient group with postoperative changes the ADC calculations were statistically significantly lower for the recurrent tumours at all b-levels (p < 0.001 for all b-levels). The sensitivity of b-50 values lower than 3.01 × 10³ mm²/s in showing recurrent tumours was 100% and the specificity was 77.78%. The sensitivity of b-400 values lower than 2.1 × 10³ mm²/s in showing recurrent tumours was 80% and the specificity was 96.3%. The sensitivity of b-800 values lower than 2.26 × 10³ mm²/s in showing recurrent tumours was 100% and the specificity was 88.89%. The sensitivity of b-1000 values lower than 2 × 10³ mm²/s in showing recurrent tumours was 93.3% and the specificity was 92.5%.

Conclusions

The ADC values obtained from diffusion-weighted images have high sensitivity and specificity in differentiating recurring soft tissue sarcomas during monitoring after treatment from postoperative changes.

Efficacy and Cost-Benefit Analysis of Magnetic Resonance Imaging in the Follow-Up of Soft Tissue Sarcomas of the Extremities and Trunk

There is no consensus regarding follow-up after soft tissue sarcoma (STS) treatment. This study examines the efficacy and the cost-benefit of MRI imaging for discovering recurrence. A retrospective analysis was performed, collecting data on patient demography, tumor characteristics, treatment, and follow-up. Imaging was correlated to the clinical course, and sensitivity, specificity, and predictive values were calculated. The number needed to screen and costs of finding recurrence are reported. Amongst 216 sarcomas, 73 (35%) exhibited local recurrence during a follow-up of 5.3 ± 3.5 years. 173 entities had complete MRI follow-up with 58 (34%) local recurrences. Thirty-three (57%) were discovered by MRI, 8 (14%) by clinical presentation, and 17 (29%) simultaneously. There was a sensitivity of 100.00%, a specificity of 89%, a positive predictive value of 32%, and a negative predictive value of 100% for detecting local recurrence with MRI. Our data confirm the modalities and intervals proposed by the German guidelines for sarcoma care. The recommended MRI intervals should not be extended. MRI is more cost-effective than clinical examination; still, both modalities should be performed together to discover the maximum number of recurrences.

Diagnostic value of MRI for detecting recurrent soft-tissue sarcoma in a long-term analysis at a multidisciplinary sarcoma center

Background

Soft-tissue sarcomas (STS) are rare tumors of the soft tissue. Recent diagnostic studies on STS mainly dealt with only few cases of STS and did not investigate the post-therapeutic performance of MRI in a routine clinical setting. Therefore, we assessed the long-term diagnostic accuracy of MRI for detecting recurrent STS at a multidisciplinary sarcoma center.

Methods

In all, 1055 postoperative follow-up MRIs of 204 patients were included in the study. MRI follow-up scans were systematically reviewed for diagnostic values (true-positive/−negative and false-positive/−negative results) in detecting recurrences. Pathological reports and follow-up MRIs were set as baseline references.

Results

The median age of the patients was 55.3 ± 18.2 years. Of the patients, 34.8% presented with recurrences. Here, 65 follow-up scans were true positive, 23 false positive, 6 false negative, and 961 true negative. The overall sensitivity and specificity of MRI for detecting recurrences were 92 and 98%, respectively, with an accuracy of 97%. For intramuscular lesions and after surgery alone the sensitivity was higher (95 and 97%, respectively) than for subcutaneous lesions and surgery with additional radiation therapy (83 and 86%, respectively), at similarly high specificities (96–98%). The 6 false-negative results were found in streaky (n = 2) and small ovoid/nodular (n = 4) recurring lesions. The false-positive lesions imitated streaky (n = 14), ovoid/nodular (n = 8), and polycyclic/multilobulated recurring tumors (n = 1). All false-positive results were found in patients in whom the primary tumors were polycyclic/multilobulated in appearance.

Conclusion

MRI shows a high diagnostic accuracy for detecting recurrent STS, with a high sensitivity and specificity. The diagnostic accuracy decreases in subcutaneous lesions and after surgery with radiation therapy, compared to intramuscular lesions and surgery alone. Radiologists should pay particular attention to streaky and small ovoid/nodular recurring lesions and patients with polycyclic/multilobulated primary tumors.

Imaging of Bone Sarcomas and Soft-Tissue Sarcomas

BACKGROUND

 In the diagnosis of bone and soft-tissue sarcomas, the continuous advancement of various imaging modalities has improved the detection of small lesions, surgical planning, assessment of chemotherapeutic effects, and, importantly, guidance for surgery or biopsy.

METHOD

 This review was composed based on a PubMed literature search for the terms "bone sarcoma," "bone cancer" and "soft tissue sarcoma," "imaging," "magnetic resonance imaging", "computed tomography", "ultrasound", "radiography", and "radiomics" covering the publication period 2005-2020.

RESULTS AND CONCLUSION

 As discussed in this review, radiography, ultrasound, CT, and MRI all play key roles in the imaging evaluation of bone and soft-tissue sarcomas. In daily practice, advanced MRI techniques complement standard MRI but remain underused, as they are considered time-consuming, technically challenging, and not reliable enough to replace biopsy and histology. PET/MRI and radiomics have shown promise regarding the imaging of sarcomas in the future.

KEY POINTS

  · Radiographs remain crucial in diagnostic imaging algorithms for sarcomas.. · US is an initial imaging study for the evaluation of superficial soft-tissue tumors.. · The role of CT continues to evolve as new techniques emerge.. · MRI allows the noninvasive evaluation of soft-tissue, osseous, and articular structures.. · Machine learning methods could improve personalized selection of therapy for patients with sarcoma..

CITATION FORMAT

· Igrec J, Fuchsjäger MH. Imaging of Bone and Soft-Tissue Sarcomas. Fortschr Röntgenstr 2021; 193: 1171 - 1182.

Appearance of recurrent dermatofibrosarcoma protuberans in postoperative MRI follow-up

PURPOSE

To analyze the appearance of recurrent dermatofibrosarcoma protuberans (DFSP) in postoperative MRI follow-up and to assess the occurrence of postoperative soft tissue changes detected in MRI.

METHODS

A total of 464 MRI follow-up scans of 32 patients with histologically proven diagnosis of DFSP were analyzed. MR imaging was performed using a 1.5T MRI system. Recurrent DFSP was examined for signal intensity, contrast behavior, appearance, and extent in MRI.

RESULTS

The mean age of the patients was 44,5±17,1 years. Recurrences of DFSP occurred 26±23.3 months after primary tumor resection in the mean (Min.: 9, Max.: 60). In 25% of the patients (n = 8), recurrences of DFSP were detected. Recurrent DFSP most often showed a nodular and homogeneous configuration with well-defined borders and marked contrast enhancement, and a hyperintense signal in PD-weighted and turbo inversion recovery magnitude sequences. All recurrences were well detected in the follow-up MRIs regardless of the performed plastic surgery procedure. Lateral and depth margins had no significant impact on the local recurrence rate. In all, 88% of the patients developed subcutaneous tissue edema (p < 0.01), followed by muscle edema (34%, p = 0.02), and postoperative seroma (22%).

CONCLUSION

Recurrent DFSP mainly appear uniform and clearly delimitable on MRI as nodular, homogeneous, and well-defined lesions with marked contrast enhancement. Therefore, MRI is a valuable tool for postsurgical follow-up. Nearly all patients develop subcutaneous edema after the resection of DFSP.

Appearance of recurrent adult fibrosarcoma of the soft tissue and loco-regional post-treatment changes on MRI follow-up

Background

Adult fibrosarcoma (AFS) is a very rare malignant soft tissue tumor, arising from malignant spindle-shaped fibroblasts. We aim to analyze the appearance of recurrent AFS with a focus on configuration and to assess the occurrence of loco-regional post-treatment changes on MRI follow-up.

Methods

One hundred sixty-eight MRI follow-up scans (1.5 T MRI) of 12 patients with histologically proven AFS were reviewed. The recurrent tumors were examined for configuration, limitation, contrast enhancement, and extent and signal intensity on MRI.

Results

The mean age of the patients was 50.2 ± 16.7 years. Forty-two percent of the patients presented recurrent AFS (n = 5). Recurrences occurred 12 ± 6.5 months after tumor resection in the mean. Patients over 55 years of age showed a significantly higher risk for recurrences (RR = 5; 95% CI, 1.8 to 31; p = 0.04). Recurrent AFS was ovoid, nodular, streaky, polycyclic, or fascicular configured with homogeneous/heterogeneous contrast enhancement and well- or ill-defined borders. The intensity of contrast enhancement ranged from rim to marked contrast enhancement. Recurrent AFS mostly showed a muscle iso-intense signal in T1-weighted and a hyperintense signal in PD-weighted/TIRM sequences. The most common post-treatment changes were subcutaneous edema (92%; p = 0.03), muscle edema (75%), and postoperative seroma (50%). Patients with the presence of muscle edema after primary tumor resection had a slightly, but not significantly higher risk for recurrences (RR = 1.75; p = 0.08).

Conclusion

Recurrent AFS shows no common configuration on MRI, as it may appear ovoid, nodular, streaky, polycyclic, or fascicular. Patients with the presence of post-treatment muscle edema have a slightly higher risk for recurrences.

Level of evidence: Level III, therapeutic study

Malignant peripheral nerve sheath tumours in magnetic resonance imaging: primary and recurrent tumour appearance, post-treatment changes, and metastases

PURPOSE

To analyse the appearance of primary and recurrent malignant peripheral nerve sheath tumours (MPNSTs) in magnetic resonance imaging (MRI) with a focus on configuration, and to assess the occurrence of loco-regional post-treatment changes and metastases during post-treatment follow-up.

MATERIAL AND METHODS

Twenty patients with histologically proven MPNST underwent post-treatment 1.5 T MRI. Primary and recurrent MPNSTs were examined for configuration, contrast enhancement, extent, and signal intensity in MRI. Loco-regional post-treatment changes and information on metastases were extracted from the follow-up.

RESULTS

MPNSTs occurred most often in the extremities (p = 0.006). Twenty per cent (n = 4) of the patients developed recurrences, with a total of 24 lesions. Recurrent MPNSTs were significantly smaller than primary MPNSTs (p = 0.003). Primary MPNSTs mostly occurred unifocally as multilobulated or ovoid and heterogeneous lesions with mostly well-defined borders. Recurrent MPNSTs purely occurred multifocally as mostly nodular (p < 0.001), multilobulated, or ovoid lesions. 80%, 65% and 30% of the patients showed post-treatment subcutaneous oedema (p = 0.002 to 0.03), muscle oedema (p = 0.02), and seroma, respectively. Twenty-five per cent (n = 5) of patients presented metastases during follow-up. The relative risk in patients with recurrences to develop lung or lymph node metastases is eightfold (p = 0.056).

CONCLUSIONS

While primary MPNSTs mostly appear unifocally as multilobulated or ovoid lesions, recurrent MPNSTs purely occur multifocally as mostly nodular lesions. Subcutaneous and muscle oedema are very common loco-regional post-treatment changes. Patients with recurrences have a higher risk for lung and lymph node metastases.

Desmoid tumor mimics local recurrence of extremity sarcoma on MRI

BACKGROUND AND OBJECTIVES

The development of desmoid fibromatosis after tumor resection may mimic local recurrence. To our knowledge, this phenomenon has not been reported after extremity sarcoma resection. We report four cases of desmoid-type fibromatosis ("desmoid tumors") mimicking local recurrence after extremity sarcoma resection.

METHODS

We retrospectively reviewed the records of patients treated for extremity sarcoma by our orthopedic oncology service from 2014 to 2019 and identified four patients with biopsy-proven desmoid tumors. We extracted clinical, pathologic, radiographic, and operative data for the primary neoplasms and desmoid tumors.

RESULTS

Four patients with postresection surveillance magnetic resonance imaging suspicious for local recurrence underwent further analysis showing desmoid tumors. Patients underwent image-guided needle biopsy, with specimens demonstrating fibromatosis-type histologic characteristics. Two cases were β-catenin positive. Desmoid tumors were managed with observation. No patient had experienced local or distant recurrence of the primary tumor at a mean follow-up of 30 months after resection (range, 23-34 months); none underwent surgery for symptoms of desmoid tumors.

CONCLUSIONS

Desmoid tumors should be considered part of the differential diagnosis when assessing patients with radiographic concern for postresection local recurrence of extremity bone and soft-tissue sarcoma. An image-guided needle biopsy can inform diagnosis and management.

Primary Intra-abdominal Ewing's Sarcoma in Adults: A Multimodality Imaging Spectrum

Ewing sarcoma (ES) and peripheral primitive neuroectodermal tumor are part of a spectrum of neoplastic diseases known as the ES family of tumors, which also includes extraosseous ES, peripheral primitive neuroectodermal tumor, malignant small-cell tumor of the thoracopulmonary region (Askin's tumor), and atypical ES. Although imaging features of these tumors have been previously described, extensive discussion about intra-abdominal manifestations is scarce in the literature. We present an imaging spectrum of these tumors in the abdomen and pelvis with particular attention to multimodality approach for staging and restaging.

Local recurrence of soft-tissue sarcoma: issues in imaging surveillance strategy

Soft-tissue sarcomas pose diagnostic and therapeutic challenges to physicians, owing to the large number of subtypes, aggressive tumor biology, lack of consensus on management, and controversy surrounding interval and duration of surveillance scans. Advances in multidisciplinary management have improved the care of sarcoma patients, but controversy remains regarding strategies for surveillance following definitive local control. This review provides an updated, comprehensive overview of the current understanding of the risk of local recurrence of soft-tissue sarcoma, by examining the literature based on features such as histological type and grade, tumor size, and resection margin status, with the aim of helping clinicians, surgeons, and radiologists to develop a tailored approach to local imaging surveillance.

Imaging in Soft Tissue Sarcomas: Current Updates

Soft tissue sarcomas (STS) are heterogeneous malignant tumors that have nonspecific imaging features. A combination of clinical, demographic, and imaging characteristics can aid in the diagnosis. Imaging provides important information regarding the tumor extent, pretreatment planning, and surveillance of patients with STS. In this article, we illustrate the pertinent imaging characteristics of the commonly occurring STS and some uncommon sarcomas with unique imaging characteristics.

Does fluid collection impact radiotherapy outcomes after wide excision of lower extremity soft tissue sarcoma?

Background

Fluid collection (FC) of lymph or blood may accumulate at the site of excision after surgery for soft tissue sarcoma, with reported incidence rates from 10% to 36%. The purpose of this study is to analyze the impact of FC on local recurrence (LR) and wound complication rates after adjuvant postoperative radiotherapy (PORT) in lower extremity soft tissue sarcoma (LE-STS).

Methods

Eighty-eight patients diagnosed with LE-STS were curatively treated with wide excision and PORT. FC developed in 51.1% of patients. Full FC volumes were included in the irradiation field throughout the full course of PORT for 36 patients (80.0%). A median of 61.2 and 63 Gy was prescribed for patients with and without FC, respectively.

Results

After a median follow-up of 4.3 years, patients with and without FC had 5-year local control rates of 77.7% and 90.8% (P = 0.105). Eight patients with FC had LR, of which six patients had recurrent tumors at or within 4 cm of the FC wall and three of these patients had out-of-field LR. Wound complication occurred after RT in 3 (6.7%) of 45 patients with FC and 1 (2.3%) of 43 patients without FC.

Conclusions

FC presents a potential risk for increased LR, particularly near the FC wall. Based on reasonable wound complication rates, we suggest the need and feasibility of fully including FC volumes in the irradiation field.

Could Routine Magnetic Resonance Imaging Detect Local Recurrence of Musculoskeletal Sarcomas Earlier? A Cost-effectiveness Study

BACKGROUND

Current practice in our unit is to perform clinical assessment and plain film radiographs at regular intervals following treatment of a bone or soft tissue sarcoma (STS). Cross-sectional imaging is used in cases with a clinical suspicion of recurrence. We aimed to investigate the effectiveness of this protocol to determine if earlier detection may have been possible had more intensive imaging been undertaken, and whether this may have affected outcome.

MATERIALS AND METHODS

We reviewed clinical records and imaging of all patients with diagnosed local recurrence (LR) in the previous 5 years to investigate: how it was diagnosed, the site and size of recurrence, and management. A value judgment was then made as to whether earlier diagnosis may have altered treatment and/or outcome.

RESULTS

161 patients with LR were identified: 87 with a STS and 74 with bone sarcoma. Median time from diagnosis to LR was 17.8 months for STS and 20.1 months for bone sarcoma. One hundred and fifteen cases (71%) were identified by the patient, 28 by routine imaging (17%), 13 by a doctor (8%), and five diagnosed by other methods. Median size of LR was 5.5 cm for STS and 5 cm for bone sarcomas. Seventy nine of the patients (49%) could have had their LR diagnosed earlier with routine imaging. Of these, 53 would have received the same treatment, but 26 (33%) could have had different treatment.

CONCLUSION

Earlier diagnosis could have led to altered management in one-third of those patients with the potential to have their LR diagnosed earlier. If all patients had regular magnetic resonance imaging, it would cost £6987 per recurrence where management was altered in imaging costs alone. We suggest a stratified approach whereby patients at highest risk of LR and those in whom early detection of LR may be easily treatable are prioritised for more intensive followup.

Gadolinium Contrast Enhancement Improves Confidence in Diagnosing Recurrent Soft Tissue Sarcoma by MRI

RATIONALE AND OBJECTIVES

To determine how utilization of postgadolinium magnetic resonance imaging (MRI) influenced reader accuracy and confidence at identifying postoperative soft tissue sarcoma (STS) recurrence among readers with various levels of expertise.

MATERIALS AND METHODS

This retrospective study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. Postoperative MRI from 26 patients with prior STS resection (13 patients with confirmed recurrence, 13 without recurrence) was reviewed. Four blinded readers of varying expertise (radiology resident, fellow, attending, and orthopedic oncologist) initially evaluated only the precontrast images and rated each MRI for recurrence on a 5-point confidence scale. Assessment was repeated with the addition of contrast-enhanced sequences. Diagnostic accuracy based on confidence ratings was evaluated using the area under the receiver operating characteristic curve (AUC). Changes in confidence ratings were calculated using Wilcoxon signed-rank test.

RESULTS

All readers demonstrated good diagnostic accuracy both with and without contrast-enhanced images (AUC >0.98 for each reader). When contrast-enhanced images were made available, the resident recorded improved confidence with both assigning (P = 0.031) and excluding recurrence (P = 0.006); the fellow showed improved confidence only with assigning recurrence (P = 0.015); and the surgeon showed improved confidence in excluding recurrence (P = 0.003). The addition of contrast-enhanced images did not significantly influence the diagnostic confidence of the attending radiologist.

CONCLUSIONS

Diagnostic accuracy of MRI was excellent in evaluating postoperative STS recurrence, and reader confidence improved depending on expertise when postgadolinium imaging was included in the assessment.

Comparison of MRI and PET-CT in detecting the loco-regional recurrence of soft tissue sarcomas during surveillance

OBJECTIVE

To investigate the diagnostic performance of MRI and PET-CT for the detection of loco-regional recurrences after soft tissue sarcoma (STS) excision.

MATERIALS AND METHODS

From Dec 2003 to Aug 2014, 394 patients with STSs, who were included in the electronic patient registry for initial or repeated surgery at our hospital, were retrospectively reviewed. We identified 152 patients who underwent regular postoperative follow-ups with both MRI and PET-CT, obtained within a 3 month period of each other. We analyzed differences in the performance of MRI and PET-CT for the diagnosis of loco-regional recurrences using McNemar's test. The receiver-operating characteristic curves and calculations of the area under the curve were used.

RESULTS

Twenty patients were found to have a loco-regional recurrence after tumor excision. For MRI and PET-CT, the sensitivities were 90.0 and 95.0 %, and the specificities 97.7 and 95.5 %, respectively, with positive predictive values of 85.7 and 76.0 % and negative predictive values of 98.5 and 99.2 %, respectively. No significant difference was detected between the sensitivities of MRI and PET-CT (p = 0.125). The area under the receiver-operating characteristic curve for PET-CT (0.952) was not significantly greater than that for MRI (0.939; p = 0.6).

CONCLUSION

MRI of the area of interest is recommended for evaluation of tumor recurrence after surgical excision of STS. PET-CT was shown to be effective for detection of STS recurrence, and comparable to MRI. However, if PET-CT or MRI findings are inconclusive, the other modality may be helpful in differentiating tumor recurrence from post-therapeutic tissue change.

The histological variants of liposarcoma: predictive MRI findings with prognostic implications, management, follow-up, and differential diagnosis

Liposarcoma is the single most common soft tissue sarcoma accounting for up to 35 % of sarcomas. It represents a histologically diverse group of soft tissue tumors that demonstrate a wide range of imaging appearances with varied behavior patterns. Correspondingly, more aggressive histological subtypes often require management that includes a combination of surgery, chemotherapy, and radiation therapy. Distinguishing among liposarcoma subtypes has important therapeutic and prognostic implications. In this manuscript, we review the liposarcoma subtypes and their histologic and MRI findings, prognostic implications, and differential diagnostic considerations.

Early detection of local recurrence after soft tissue sarcoma resection and flap reconstruction

PURPOSE

Flap reconstruction has become an essential component in soft tissue sarcoma treatment. However, the clinical features of local recurrence after soft tissue sarcoma resection and flap reconstruction remain unclear. The present study aimed to establish effective follow-up strategies after soft tissue sarcoma resection and flap reconstruction.

METHODS

Data from patients who underwent soft tissue sarcoma resection and immediate flap reconstruction were retrospectively reviewed. Follow-up after surgery included history taking and physical examination during every visit to the hospital. Magnetic resonance imaging to evaluate the primary site was performed six months after the end of treatment then annually for ten years. The methods of detection of local recurrence were assessed.

RESULTS

A total of 229 consecutive patients were included in the present study. During a median follow-up period of 40 months, 33 patients (14.4%) developed local recurrence. Twenty-three recurrences that occurred on the margin of the transferred flap were detected as palpable mass prior to radiological assessment; among the remaining ten recurrences that occurred in the deep layer of the transferred flap, six were detected by abnormal clinical findings and four were clinically occult and detected by surveillance radiological assessment.

CONCLUSIONS

Surveillance radiological assessment has an important role in early detection of local recurrence that develops in the deep layer of the transferred flap. Therefore, meticulous clinical assessment combined with routine radiological study should be performed during follow-up evaluation for local recurrence after soft tissue sarcoma resection and flap reconstruction.

ACR Appropriateness Criteria Follow-Up of Malignant or Aggressive Musculoskeletal Tumors

Appropriate imaging modalities for the follow-up of malignant or aggressive musculoskeletal tumors include radiography, MRI, CT, (18)F-2-fluoro-2-deoxy-D-glucose PET/CT, (99m)Tc bone scan, and ultrasound. Clinical scenarios reviewed include evaluation for metastatic disease to the lung in low- and high-risk patients, for osseous metastatic disease in asymptomatic and symptomatic patients, for local recurrence of osseous tumors with and without significant hardware present, and for local recurrence of soft tissue tumors. The timing for follow-up of pulmonary metastasis surveillance is also reviewed. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three 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.

Power-assisted liposuction (PAL) of multiple symmetric lipomatosis (MSL)--a longitudinal study

BACKGROUND

Multiple symmetric lipomatosis (MSL) is a rare condition leading to grotesque disfigurement. Complete removal is almost impossible and recurrences inevitable. The objective of this study was to evaluate powered-assisted liposuction (PAL) for the treatment of MSL.

METHODS

Magnetic resonance imaging (MRI) was performed before and after surgery for quality assessment. To exclude malignancy incisional biopsies were taken before surgery. Outcome measures included aspiration volumes, duration of surgery, early morbidity, recurrence rates, and overall patient satisfaction.

RESULTS

Seven male patients aged between 43 and 70 years were identified. The mean liposuction volume equaled 2948±1566 mL, the mean surgery time 74±28 minutes. One hematoma was observed, whereas 1 recurrence rate was noticed after a mean follow-up of 14 months. Malignancy was excluded by histology in 5 patients. Preoperative MRI confirmed the diagnosis with no signs for malignancy and showed an efficient removal of the lesions. After a mean follow-up of 18 months, a high patient satisfaction was achieved.

CONCLUSION

PAL can serve as an efficient method for the treatment of MSL. It has a significant effect on tightening of the skin, leading to a high patient satisfaction.

Differentiation of Benign Fluid Collections from Soft-Tissue Sarcomas on FDG-PET/CT

OBJECTIVE

To assess the diagnostic performance of (18)F-FDG PET-CT in differentiating soft tissue sarcomas (STSs) from benign fluid collections (BFs).

MATERIALS AND METHODS

Four readers independently reviewed 100 lesions on (18)F-FDG PET-CT and subjectively classified each lesion as an STS or BF and scored the spatial pattern of (18)F-FDG avidity (SP) of each on a 4-point ordered scale (thin, moderate, thick, solid).

RESULTS

Subjective assessment by readers allowed sensitive (91%-98%) differentiation of STSs from BFs, with lower specificity (59%-91%). The STSs had significantly higher SUVmax (median 10.7, range: 2.0-33.7) than BFs (median 2.8, range: 1.1-12.3). Reader agreement in assessment of SP had average κ = 0.61 (range 0.46-0.70). Classification of thick or solid SP as STS yielded an inter-reader averaged sensitivity and specificity of 69% and 98%, respectively. The presence of thick or solid SP resulted in 14.1-fold increase in partial odds of STS. Each unit increase in SUVmax resulted in 1.35-fold increase in partial odds of STS. The receiver operating characteristic (ROC) curves and 95% intervals for SUVmax alone and SUVmax + SP overlapped. The average subjective assessments for the four readers and estimated performance of using SP alone were both contained within the 95% intervals of the two ROC curves.

CONCLUSIONS

(18)F-FDG PET-CT is a sensitive modality for differentiating STSs from BFs. SUVmax and SP are significantly associated with STS. Classification schemes based upon SUVmax alone or augmented with SP can be useful for distinguishing STS from BF.

Following unenhanced MRI assessment for local recurrence after surgical resection of mesenchymal soft tissue tumors, do additional gadolinium-enhanced images change reader confidence or diagnosis?

PURPOSE

Evaluate if gadolinium enhanced MR imaging (GeMRI) improves confidence, changes the final diagnosis, or improves accuracy in the assessment of musculoskeletal (MSK) tumor residual or recurrence following surgical resection. We also assess if different experience levels change the above results.

METHODS AND MATERIALS

Initially, pre-contrast images were independently reviewed by two radiologists, one with 25 years of experience (R1) and one undergoing MSK specialty training (R2). Two questions were answered: (1) Mass present? and (2) Likelihood of malignancy? Subsequently, both pre-contrast and post-contrast images were independently reviewed. The same questions were again answered plus four others including if GeMRI changed mass characterization, better defined cystic versus solid, better defined tumor extent, or improved conspicuity. Lastly, the readers answered whether GeMRI changed confidence, and changed their final diagnosis. Histologic diagnoses were available in 43 cases, with the remaining 44 cases based upon clinical and/or imaging follow-up.

RESULTS

GeMRI definitely improved confidence in 8/7 cases, and slightly improved confidence in 20/29 cases and changed the final diagnosis in 11/8 cases for R1 and R2 respectively. Positive and negative predictive values statistically improved for R2 (positive predictive value 36.4% versus 50%, p=0.02; negative predictive value 75.4% versus 79.1%, p=0.04) but not for R1. Reader concordance for malignancy improved with GeMRI (κ=0.44 pre-contrast and κ=0.71 post-contrast).

CONCLUSION

GeMRI improved reader confidence, improved reader concordance and modestly improved accuracy for the less experienced reader. Where possible, GeMRI should be used in the assessment of MSK tumor residual or recurrence.

Imaging of soft tissue and osseous sarcomas of the extremities

Soft tissue and osseous sarcomas of the extremities are uncommon malignancies that represent very important diagnostic entities because of their aggressive nature. Radiologic investigations, including plain film, computed tomography, contrast-enhanced magnetic resonance imaging; scintigraphy, ultrasound, and positron emission tomography-computed tomography, play critical roles in providing a differential, establishing the diagnosis, demonstrating prognostic characteristics, and tailoring tumor treatment. The purpose of this review is to describe the most common soft tissue and osseous sarcomas of the extremities, with emphasis on their plain film and magnetic resonance imaging characteristics with the aim of aiding the reader to accurately describe the important imaging features and generate an appropriate differential diagnosis to aid the referring clinician with prompt appropriate management and treatment.

CT scans for pulmonary surveillance may be overused in lower-grade sarcoma

Chest CT scans are often used to monitor patients after excision of a sarcoma. Although sensitive, CT scans are more expensive than chest radiographs and are associated with possible health risks from a higher radiation dose. We hypothesized that a program based upon limited CT scans in lower-grade sarcoma could be efficacious and less expensive. We retrospectively assigned patients to a high-risk or low-risk hypothetical protocol. Eighty-three low- or intermediate-grade soft tissue sarcomas met our inclusion criteria. Eight patients had pulmonary metastasis. A protocol based on selective CT scans for high-risk patients would have identified seven out of eight lesions. The incremental cost-effectiveness ratio for routine CT scans was $731,400. A program based upon selective CT scans for higher-risk patients is accurate, spares unnecessary radiation to many patients, and is less expensive.

Physiology and pathophysiology of incidental findings detected on FDG-PET scintigraphy

A routine feature of positron emission tomography/computed tomography (PET/CT) imaging is whole-body acquisition that results in many unexpected findings identified outside of the primary region of abnormality. Furthermore, (18)F-fluorodeoxyglucose (FDG) is a marker of glycolysis and does not specifically accumulate in malignancy. Understanding the physiology and pathophysiology of normal FDG distribution and common incidental findings is therefore essential to the physician interpreting whole-body FDG-PET/CT studies. Whereas many incidental findings are benign and of limited clinical significance, others represent uncommon manifestations of the primary malignancy, second malignancies, or various clinically significant pathologic processes. Patients with a single malignancy are at greater risk of developing synchronous or metachronous second malignancies, possibly related to exposure to shared carcinogenic agents or presence of prooncogenic mutations. The decision of how to pursue an intervention on the basis of an incidental finding is generally left to clinical judgment.

Magnetic resonance imaging appearances following hindquarter amputation for pelvic musculoskeletal malignancy

OBJECTIVE

To describe our experience of the magnetic resonance imaging (MRI) appearances after hindquarter amputation, focusing on the normal pattern of time-related changes in signal intensity within the amputation flap and appearances of local disease recurrence.

MATERIALS AND METHODS

This was a retrospective review of the records of patients identified on our orthopaedic oncology database who had undergone hindquarter amputation at our centre. Examinations were divided into one group consisting of 'normal' postoperative findings and another group demonstrating local recurrence. 'Normal' postoperative findings were assessed for signal intensity, morphology and presence of the 'muscle texture sign' within the amputation flap. Examinations were grouped according to time from surgery. Examinations demonstrating local recurrence were assessed for site, signal intensity, morphology and axial dimensions of recurrent tumour. Comparison was made to pre-operative imaging.

RESULTS

Thirty-five patients with postoperative MR images were identified. Seventy-seven examinations were reviewed (range 1-18 per patient). The 'normal group' comprised 18 patients (seven female, 11 male, mean age 44 years, range 16-75 years), with 47 examinations reviewed. The 'muscle texture sign' was preserved in all examinations in this group. Up to 6 months after surgery, 100% (10) of examinations showed hyperintense T2- and short-tau inversion recovery (STIR-weighted) signals within the muscle flap, indicating oedema. Only after 4 years was the muscle flap signal isointense in all cases (13). Up to 6 months after surgery, 50% (5 of 10) of examinations demonstrated flap swelling, but after 1 year, 100% (28) showed atrophy. Twenty percent (2 of 10) of examinations 0-6 months from surgery showed hyperintense T1-weighted signal within the muscle flap, consistent with fatty infiltration, but after 2 years, 100% (20) showed a hyperintense T1-weighted signal. The 'local recurrence' group comprised 20 patients (six female, 14 male, mean age 45.7 years, range 14-69 years), with 30 examinations demonstrating recurrent disease or metastasis. There were 23 recurrent tumours, of which 43% (10) were in the muscle component of the amputation flap, 13% (3 of 23) were in subcutaneous tissues of the flap, 13% (3 of 23) were at the posterior margin of the bone resection and 13% (3 of 23) were paraspinal. All recurrent tumours demonstrated hyperintense T2 and STIR signals. The signal intensity pattern of recurrence closely followed that of the original tumour. The 'muscle texture sign' was absent in all examinations demonstrating recurrence in muscle flap.

CONCLUSION

A pattern of time-related signal intensity and morphological changes is observed within normal hindquarter amputation flaps on MRI. Recurrent disease is most likely to occur within the muscle flap, typically of high T2-weighted signal intensity and characteristically follows the signal pattern of the original tumour.

Contemporary imaging in sarcoma

Sarcomas are a heterogeneous group of >50 subtypes of neoplasm. It is imperative to obtain appropriate imaging of these tumors in order to adequately assess, characterize, and stage bone and soft tissue sarcomas. Anatomic imaging such as radiographs, computed tomography, and magnetic resonance imaging (MRI) remain the foundation for both biopsy planning and postoperative evaluation of these neoplasms. However, anatomic imaging may not be entirely accurate in the evaluation of treatment response. Newer techniques, such (18)F-fluorodeoxyglucose positron emission tomography, are being used to evaluate distant metastases. Newer radiopharmaceuticals, such as (18)F-fluorodeoxythymidine, are being developed to assist in the differentiation between benign and low-grade malignant neoplasms. Newer functional imaging techniques, such as dynamic contrast-enhanced MRI and diffusion-weighted imaging, among others, are being developed to evaluate treatment response.