VIDEO: Preoperative CT Angiography for Scapula Osteocutaneous Free Flap Reconstructions.

OBJECTIVE. The objective of this video article is to discuss the use of the scapular osteocutaneous free flap in reconstructive procedures. We attempt to discuss normal and variant vascular anatomy, image acquisition via CT angiography, and image interpretation as well as computer-assisted design and manufacturing. CONCLUSION. The scapular osteocutaneous free flap is commonly used for maxillary and mandibular reconstructive surgery. The complex vasculature supplying the scapular region allows flap versatility. There are anatomic variations in the origin of the circumflex scapular and angular arteries. Our method of performing and reporting CT angiography for patients scheduled to undergo scapular osteocutaneous free flap procedures provides a reliable and reproducible means of communicating important elements of vasculature to surgeons. This in turn can facilitate the manufacturing of custom scapular cutting guides and improve surgical outcomes.

The effects of granulocyte colony-stimulating factor on MR images of bone marrow.

Granulocyte colony-stimulating factor (G-CSF) analogs such as filgrastim/pegfilgrastim are increasingly used to enhance neutrophilic recovery after chemotherapy. It is widely known that, physiologically, pegfilgrastim stimulates marrow mitotic activity and induces marrow reconversion from fatty to cellular. However, there is limited literature discussing the effects of pegfilgrastim on musculoskeletal magnetic resonance imaging, with the consensus that marrow reconversion secondary to pegfilgrastim therapy is easily confounded with a malignant process, especially in patients with a history of cancer. We attempt to discuss the expected changes and MRI findings after pegfilgrastim therapy through a summary of current literature. Additionally, we provide images from our own practice to support the previously established findings. G-CSF-stimulated reconversion can appear as patchy expansions of baseline hematopoietic marrow, but can also appear to be diffusely homogeneous, adding to its ambiguity. We conclude that using a baseline MRI, clinical information, and assessing sequential MRI changes in conjunction with pegfilgrastim therapy may aid the differentiation between benign and pathological change. We expand our discussion to include the effects of novel technologies, such as whole-body MRI, chemical shift imaging, and contrast agents in helping the distinction.

VIDEO: Preoperative CT Angiography for Fibular Free Flap Reconstructions.

OBJECTIVE: The objective of this video article is to provide an introduction to the use of fibular free flaps. Normal and variant vascular anatomy of the fibular free flap is discussed, as are imaging acquisition and CT angiography interpretation, computer-assisted design and manufacturing, and the limitations of the fibular free flap. CONCLUSION: The fibular free flap is commonly used for head and neck reconstructive surgery. Variation exists between individuals regarding the origin of the peroneal artery and the perforating arteries. Our method of performing CT angiography and reporting its findings for patients undergoing a fibular free flap procedure provides a reproducible means of identifying important elements of the vasculature and effectively communicating their locations to surgeons. Accurate communication can maximize the success of the flap harvesting and the preoperative manufacture of custom fibular cutting guides.

A flexible fast spin echo triple-echo Dixon technique.

PURPOSE: To develop a flexible fast spin echo (FSE) triple-echo Dixon (FTED) technique. METHODS: An FSE pulse sequence was modified by replacing each readout gradient with three fast-switching bipolar readout gradients with minimal interecho dead time. The corresponding three echoes were used to generate three raw images with relative phase shifts of -θ, 0, and θ between water and fat signals. A region growing-based two-point Dixon phase correction algorithm was used to joint process two separate pairs of the three raw images, yielding a final set of water-only and fat-only images. The flexible FTED technique was implemented on 1.5T and 3.0T scanners and evaluated in five subjects for fat-suppressed T2-weighted imaging and in one subject for post-contrast fat-suppressed T1-weighted imaging. RESULTS: The flexible FTED technique achieved a high data acquisition efficiency, comparable to that of FSE, and was flexible in scan protocols. The joint two-point Dixon phase correction algorithm helped to ensure consistency in the processing of the two separate pairs of raw images. Reliable and uniform separation of water and fat was achieved in all of the test cases. CONCLUSION: The flexible FTED technique incorporates the benefits of both FSE and Dixon imaging and provided more flexibility than the original FTED in applications such as fat-suppressed T2-weighted and T1-weighted imaging. Magn Reson Med 77:1049-1057, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

VIDEO: Preoperative CT Angiography for Anterolateral Thigh Flap Reconstructions.

OBJECTIVE: This video article will review the relevant vascular anatomy of the anterolateral thigh flap, describe the CT angiography (CTA) image acquisition, and describe how to report the locations of the perforating arteries along with characteristics that may be important to the surgeon. CONCLUSION: Our method of performing and reporting CTA for patients scheduled to undergo anterolateral thigh flap reconstruction provides a reproducible method of identifying perforating vessels and communicating their location to surgeons.

Glomangiomatosis of the sciatic nerve: a case report and review of the literature.

Glomus tumors are hamartomas, which tend to occur in sites rich in glomus bodies, such as the subungual regions of digits or the deep dermis of the palm, wrist, forearm, and foot. Very rarely, they may involve peripheral nerves. We describe a patient, who, following surgical resection of a solitary glomus tumor of the left distal sciatic nerve in his teens, had recurrence with development of multiple tumors in the course of the nerve over several years. To our knowledge, this is the only known case of glomangiomatosis involving a major peripheral nerve.

Follow-up of the soft tissue sarcoma patient.

Despite optimal treatment, patients with soft tissue sarcoma are at risk for recurrence and therefore appropriate surveillance is critical. At minimum, regularly scheduled clinical assessments and chest X-rays are necessary. Consensus guidelines are available; however, surveillance strategies must be personalized based on the risk for recurrence and inherent disease biology. Further research is needed on a number of issues, including the impact of surveillance on clinical outcome and the utility of molecular surveillance.

Contemporary imaging of soft tissue sarcomas.

Imaging plays an important role in the diagnosis, biopsy, staging, and follow-up of patients with soft tissue sarcomas. General principles of imaging diagnosis of soft-tissue sarcomas using radiography, ultrasound, CT, MRI, and PET/CT will be discussed, with emphasis on the role of location, internal fat and calcification, presence of myxoid stroma, and enhancement characteristics.

Regression of an enchondroma: a case report and proposed etiology.

Enchondromas are common benign bone lesions that are found in the medullary cavity of tubular bones, usually at the metaphysis. Regression is highly unusual, and loss of matrix mineralization in an existing enchondroma should prompt investigation for malignant transformation. We present the case of a 50-year-old woman with an enchondroma of the proximal humeral metadiaphysis, which underwent loss of matrix mineralization that corresponded to replacement with marrow fat on MRI. This transformation of the cartilage tumor matrix into normal bone marrow may occur in a process similar to that seen with endochondral ossification.

Locoregional disease patterns in well-differentiated and dedifferentiated retroperitoneal liposarcoma: implications for the extent of resection?

BACKGROUND: Well-differentiated (WD)/dedifferentiated (DD) liposarcoma is the most common soft tissue sarcoma of the retroperitoneum. The frequency of distant metastasis is low and the major burden of disease is locoregional. We sought to define the patterns of locoregional disease to help guide surgical decision making. METHODS: Data were collected from 247 patients with de novo or recurrent tumors treated at our institution from 1993 to early 2012. The number and location of tumors at both initial presentation and subsequent locoregional recurrence were determined by combined analysis of operative dictations and radiologic imaging. RESULTS: Thirty-four percent of patients had multifocal locoregional disease (two or more tumors) at initial presentation to our institution, including 9 % who had tumors at synchronous remote retroperitoneal sites. The impact of multifocal disease on overall survival was dependent on histologic subtype (WD vs. DD) and disease presentation (de novo vs. recurrence) at the time of resection. Among patients with initial unifocal disease, 57 % progressed to multifocal locoregional disease with subsequent recurrence, including 11 % with new tumors outside of the original resection field. No clinicopathologic or treatment-related variable, including the type or extent of resection, was predictive of either multifocal or 'outside field' progression. CONCLUSIONS: Multifocal disease is common in patients with WD/DD retroperitoneal liposarcoma, and tumors can also develop at remote, locoregional sites. Surgical resection remains the primary method of locoregional control in this disease; however, the aggressiveness of resection should be individualized, with consideration of both tumor and patient-related factors.

FDG PET/CT of primary bone tumors.

OBJECTIVE: Numerous primary bone tumors are encountered on (18)F-FDG PET/CT, and many are FDG avid. The degree of FDG uptake in bone tumors does not necessarily reflect malignant potential. In conjunction with radiographs, evaluation of morphologic characteristics on the CT portion of PET/CT scans is important for characterization of the lesions. FDG PET/CT has been found to be useful for staging and has also been found to reflect prognosis in some primary bone malignancies. The purpose of this article is to familiarize the reader with topics regarding FDG PET/CT and both malignant and benign primary bone tumors. CONCLUSION: FDG uptake alone is not adequate for characterizing primary bone tumors, and morphologic evaluation is an important factor in the interpretation of PET/CT scans. After diagnosis, FDG avidity and morphologic features can play an important role in staging and determining response to therapy. On completion of this article, readers should have an improved ability to evaluate the FDG uptake and CT morphologic features of malignant and benign primary bone tumors. Readers should also have a better understanding of the potential role of FDG PET/CT in the management of patients with osteosarcoma and Ewing sarcoma.

Cancer Radiomic and Perfusion Imaging Automated Framework: Validation on Musculoskeletal Tumors.

PURPOSE: Limitations from commercial software applications prevent the implementation of a robust and cost-efficient high-throughput cancer imaging radiomic feature extraction and perfusion analysis workflow. This study aimed to develop and validate a cancer research computational solution using open-source software for vendor- and sequence-neutral high-throughput image processing and feature extraction. METHODS: The Cancer Radiomic and Perfusion Imaging (CARPI) automated framework is a Python-based software application that is vendor- and sequence-neutral. CARPI uses contour files generated using an application of the user's choice and performs automated radiomic feature extraction and perfusion analysis. This workflow solution was validated using two clinical data sets, one consisted of 40 pelvic chondrosarcomas and 42 sacral chordomas with a total of 82 patients, and a second data set consisted of 26 patients with undifferentiated pleomorphic sarcoma (UPS) imaged at multiple points during presurgical treatment. RESULTS: Three hundred sixteen volumetric contour files were processed using CARPI. The application automatically extracted 107 radiomic features from multiple magnetic resonance imaging sequences and seven semiquantitative perfusion parameters from time-intensity curves. Statistically significant differences (P < .00047) were found in 18 of 107 radiomic features in chordoma versus chondrosarcoma, including six first-order and 12 high-order features. In UPS postradiation, the apparent diffusion coefficient mean increased 41% in good responders (P = .0017), while firstorder_10Percentile (P = .0312) was statistically significant between good and partial/nonresponders. CONCLUSION: The CARPI processing of two clinical validation data sets confirmed the software application's ability to differentiate between different types of tumors and help predict patient response to treatment on the basis of radiomic features. Benchmark comparison with five similar open-source solutions demonstrated the advantages of CARPI in the automated perfusion feature extraction, relational database generation, and graphic report export features, although lacking a user-friendly graphical user interface and predictive model building.

Posttraumatic intramedullary osteochondroma: report of a case.

We present a rare osteochondroma, which instead of being the usual exophytic growth outside bone, grew inward into the medullary cavity of distal femur in a patient with prior trauma to his knee. Except for its intramedullary location, the benign tumor had all the classic radiographic and pathologic features of typical osteochondroma.

Changes in psoas muscle size and ambulatory function after internal hemipelvectomy without reconstruction.

Internal hemipelvectomy without reconstruction of the pelvis is a viable treatment for pelvic sarcoma; however, the time it takes to return to excellent function is quite variable. Some patients require greater time and rehabilitation than others. To determine if psoas muscle recovery is associated with changes in ambulatory function, we retrospectively evaluated psoas muscle size and limb-length discrepancy (LLD) before and after treatment and their correlation with objective functional outcomes. T1-weighted MR images were evaluated at three intervals for 12 pelvic sarcoma patients following interval hemipelvectomy without reconstruction. Correlations between the measured changes and improvements in Timed Up and Go test (TUG) and gait speed outcomes were assessed both independently and using a stepwise multivariate regression model. Increased ipsilesional psoas muscle size from three months postoperatively to latest follow-up was positively correlated with gait speed improvement (r = 0.66). LLD at three months postoperatively was negatively correlated with both TUG (r = -0.71) and gait speed (r = -0.61). This study suggests that psoas muscle strengthening and minimizing initial LLD will achieve the greatest improvements in ambulatory function. LLD and change in hip musculature remain substantial prognostic factors for achieving the best clinical outcomes after internal hemipelvectomy. Changes in psoas size were correlated with the amount of functional improvement. Several patients in this study did not return to their preoperative ipsilateral psoas size, indicating that monitoring changes in psoas size could be a beneficial rehabilitation strategy.

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

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

Role of Apparent Diffusion Coefficient Map-Based First- and High-Order Radiomic Features for the Discrimination of Sacral Chordomas and Chondrosarcomas With Overlapping Conventional Imaging Features.

PURPOSE: Chondrosarcomas arise from the lateral pelvis; however, midline chondrosarcomas (10%) display similar imaging features to chordoma, causing a diagnostic challenge. This study aims to determine the diagnostic accuracy of apparent diffusion coefficient (ADC)-based radiomic features and two novel diffusion indices for differentiating sacral chordomas and chondrosarcomas. METHODS: A retrospective, multireader review was performed of 82 pelvic MRIs (42 chordomas and 40 chondrosarcomas) between December 2014 and September 2021, split into training (n = 69) and validation (n = 13) data sets. Lesions were segmented on a single slice from ADC maps. Eight first-order features (minimum, mean, median, and maximum ADC, standard deviation, skewness, kurtosis, and entropy) and two novel indices: restriction index (RI, proportion of lesions with restricted diffusion) and facilitation index (FI, proportion of lesions with facilitated diffusion) were estimated. One hundred seven radiomic features comparing patients with chondrosarcoma versus chordoma were sorted based on mean group differences. RESULTS: There was good to excellent interobserver reliability for eight of the 10 ADC metrics on the training data set. Significant differences were observed (P < .005) for RI, FI, median, mean, and skewness using the training data set. Optimal cutpoints for diagnosis of chordoma were RI > 0.015; FI < 0.25; mean ADC < 1.7 × 10-3 mm2/s; and skewness >0.177. The optimal decision tree relied on FI. In a secondary analysis, significant differences (P < .00047) in chondrosarcoma versus chordoma were found in 18 of 107 radiomic features, including six first-order and 12 high-order features. CONCLUSION: The novel ADC index, FI, in addition to ADC mean, skewness, and 12 high-order radiomic features, could help differentiate sacral chordomas from chondrosarcomas.

A history of radiologic pathology correlation at the Armed Forces Institute of Pathology and its evolution into the American Institute for Radiologic Pathology.

The evolution of the Armed Forces Institute of Pathology (AFIP) has played an important role in the history of pathology education and in radiologic pathology correlation in the United States. From its humble beginnings as a museum, showcasing dried and varnished morbid specimens--human relics of the Civil War, the institute became a leader in pathology. Later, it became a center of instruction for radiology residents seeking to understand the pathologic findings that underlay the radiologic appearance of disease. Images were gathered by the AFIP and the American Registry of Pathology (ARP) and have been used in research and education in radiology and other fields (ophthalmology, otalaryngology, dermatology, obstetrics and gynecology, and surgery). Despite the contributions of the AFIP, the ARP, and the Radiologic Pathology Correlation Course, high-ranking members of the military and the federal government frowned on a military-owned educational system that also served civilians. Although support from the radiology community dissuaded military officers and federal officials from taking action against the participation of civilians, the 2005 Base Realignment and Closure (BRAC) provisions mandated the disestablishment of the AFIP, forcing the redistribution of some of its resources to other military-only organizations and disbanding other AFIP functions. To ensure that the correlation course, known to radiology residents as the "rad-path" course, was not a casualty of the BRAC, the American College of Radiology (ACR) and leaders of the AFIP and ARP agreed that the ACR should continue this vital educational endeavor. In January 2011, the American Institute for Radiologic Pathology of the ACR debuted and successfully instructed 268 radiology residents, including 40 international residents. The faculty and staff, who had been part of the course at the AFIP, continue to help enrich and improve the course established by their predecessors.

Fast Dixon whole-body MRI for detecting distant cancer metastasis: a preliminary clinical study.

PURPOSE: To evaluate the feasibility of fast Dixon whole-body (WB) magnetic resonance imaging (MRI) for detecting bone and liver metastasis in clinical patients and to compare its performance with skeletal scintigraphy (SS) for detecting bone metastases using reference imaging with >1 year follow-up as the gold standard. MATERIALS AND METHODS: Twenty-nine patients with bone metastases prospectively underwent WB MRI and SS. WB MRI included coronal T2, axial T1 with and without intravenous gadolinium (including triphasic liver sequences), and axial diffusion-weighted imaging, plus spinal sagittal postcontrast T1-weighted images. The skeleton was divided into 16 segments. Reviewers blinded to other images identified up to five lesions per segment and rated them using a five-point confidence scale for metastatic disease. Sensitivities and specificities were compared using the McNemar test. RESULTS: The sensitivity of WB MRI and SS in detecting bone metastases was 70.8% and 59.6% (P = 0.003), respectively; specificity was 89.1% and 98.7% (P < 0.0001). WB MRI detected all livers with metastases (n = 8). One focal nodular hyperplasia was classified as a metastasis on WB MRI. CONCLUSION: Fast Dixon WB MRI is feasible in clinical patients, highly specific, and more sensitive than SS in detecting bone metastases, and can detect metastases of the liver.

Skeletal muscle metastases: a three-part study of a not-so-rare entity.

OBJECTIVE: Our purposes were to explore the epidemiology of metastases to skeletal muscle and their detection on fused positron emission tomography and computed tomography. MATERIALS AND METHODS: We evaluated the epidemiology of skeletal muscle metastases in the literature and among cases from our hospital and studied the prevalence and appearance of skeletal muscle metastases among 433 patients undergoing fused positron emission tomography and computed tomography for non-small-cell lung cancer. RESULTS: We found 264 cases of skeletal muscle metastases in 151 articles. Mean age was 57.8 years with 67% men. At our hospital we studied 70 cases. Mean patient age was 55.7 years with 63% men. The most common source was lung cancer, and the most common site of involvement was the muscles of the trunk. Among our lung cancer patients undergoing fused positron emission tomography and computed tomography, we found 7 (1.6%) with skeletal muscle metastases. In only one of these seven patients was the metastasis first discovered by another imaging modality. In one patient discovery of the metastasis at fused positron emission tomography and computed tomography changed management. CONCLUSION: Skeletal muscle metastases are not rare. They may be more apparent at fused positron emission tomography and computed tomography than at other staging examinations, particularly contrast-enhanced CT scanning. Radiologists need to be alert to their presence when interpreting staging examinations in cancer patients.

Initial staging impact of fluorodeoxyglucose positron emission tomography/computed tomography in locally advanced breast cancer.

PURPOSE: Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) may reveal distant metastases more accurately than conventional imaging (CT, skeletal scintigraphy, chest radiography). We hypothesized that patients diagnosed with stage III noninflammatory breast cancer (non-IBC) and IBC by conventional imaging with PET/CT have a better prognosis than patients diagnosed without PET/CT. PATIENTS AND METHODS: We retrospectively identified 935 patients with stage III breast cancer in 2000-2009. We compared the relapse-free survival (RFS) and overall survival (OS) times of patients diagnosed by conventional imaging with those of patients diagnosed by conventional imaging plus PET/CT. Univariate and multivariate Cox proportional hazards regression models were used to assess associations between survival and PET/CT. RESULTS: RFS and OS times were not significantly different between patients imaged with PET/CT and those imaged without PET/CT. However, the RFS time in IBC patients was significantly different between patients imaged with PET/CT and those imaged without PET/CT on both univariate (hazard ratio [HR], 0.43; p = .014) and multivariate (HR, 0.33; p = .004) analysis. There was a trend for a longer OS duration in IBC patients imaged with PET/CT. CONCLUSION: Among IBC patients, adding PET/CT to staging based on conventional imaging might detect patients with metastases that were not detected by conventional imaging. The use of conventional imaging with PET/CT for staging in non-IBC patients is not justified on the basis of these retrospective data. The use of conventional imaging plus PET/CT in staging IBC needs to be studied prospectively to determine whether it will improve prognosis.