Scott D. Wuertzer

Spectrum of Fat-containing Soft-Tissue Masses at MR Imaging: The Common, the Uncommon, the Characteristic, and the Sometimes Confusing

Fat-containing tumors are the most common soft-tissue tumors encountered clinically. The vast majority of fat-containing soft-tissue masses are benign. Lipomas are the most common benign fat-containing masses and demonstrate a characteristic appearance at magnetic resonance (MR) imaging. Less common benign soft-tissue masses include lipoblastoma, angiolipoma, spindle cell lipoma/pleomorphic lipoma, myolipoma, chondroid lipoma, lipomatosis of nerve, lipomatosis, hibernoma, and fat necrosis. Well-differentiated liposarcomas (WDLPSs)/atypical lipomatous tumors (ALTs) are locally aggressive soft-tissue masses that do not metastasize. Biologically more aggressive liposarcomas include myxoid, pleomorphic, and dedifferentiated liposarcomas. At MR imaging, lipomas typically resemble subcutaneous fat but may contain a few thin septa. The presence of thick, irregular, enhancing septa and nonfatty soft-tissue mass components suggests liposarcoma rather than lipoma. However, benign lipomatous lesions and WDLPS/ALT often have overlapping MR imaging findings. Distinguishing WDLPS/ALT from a benign lipomatous lesion or from fat necrosis at imaging can be challenging and often requires histologic evaluation. We present the spectrum of fat-containing masses, using the World Health Organization classification of adipocytic tumors, with an emphasis on commonly encountered lesions, characteristic MR imaging findings associated with specific tumors, and overlapping MR imaging findings of certain tumors that may require histologic sampling. We also briefly discuss the role of molecular markers in proper characterization and classification of fat-containing soft-tissue masses. (©)RSNA, 2016.

Verrucous carcinoma of the foot and enhancement assessment by MRI

Verrucous carcinoma (VC), also known as epithelioma cuniculatum, of the foot is an uncommon low-grade squamous cell carcinoma with slow, progressive local invasion with minimal dysplasia and low potential for metastasis. We report on a case of VC and the enhancement pattern associated with it on magnetic resonance (MR) imaging. MR imaging revealed a plantar ulcer with an interesting pattern of enhancement at the base of the mass. The interface between the mass and the normal stroma exhibited a fine-filamentous pattern of enhancement, analogous to teased cotton wool, with impressive correlation to the histological appearance of our specimen. It is our opinion that VC could be included in the differential of a plantar ulcer associated with a mass that exhibits this enhancement pattern.

High-Resolution 3-T MRI of the Fingers: Review of Anatomy and Common Tendon and Ligament Injuries

OBJECTIVE. With high-resolution 3-T MRI, the complex anatomy of the fingers can be imaged in exquisite detail to provide an accurate diagnosis of clinically important ligament and tendon injuries. CONCLUSION. We present our 3-T MRI protocol using a dedicated hand-and-wrist coil and review normal MRI anatomy of the fingers. We emphasize a systematic approach to the interpretation of finger MRI examinations and illustrate this approach with examples of tendon and ligament abnormalities.

The imaging findings of impingement syndromes of the lower limb

In this article we provide an overview of impingement syndromes of the lower limb. At the level of the hip, femoroacetabular and ischiofemoral impingement are recognised. At the level of the knee, we discuss Hoffas fat pad impingement, suprapatellar fat pad impingement, pericruciate impingement, and iliotibial band syndrome. The impingement syndromes associated with anterior cruciate ligament (ACL) repair and intercondylar osteophytes are also illustrated. Most impingement syndromes are described at the level of the ankle. These include, anterior, anterolateral, posterior, anteromedial, posterior, and posterolateral impingement. For these conditions, we describe the best technique and expected imaging findings. It should be kept in mind that many of these findings have been observed in the asymptomatic population. Impingement is essentially a clinical diagnosis and imaging findings should be considered as supportive elements for this clinical diagnosis.

Misclassification of Pelvic Ring Injuries in the National Trauma Data Bank.

Background: The American College of Surgeons has advocated for all trauma centers to participate in the National Trauma Data Bank (NTDB); however, no previous study has evaluated the accuracy of coding included in this data bank. The purpose of this study was to determine whether pelvic ring injuries are coded accurately in the NTDB and, if not, how they were misclassified. Methods: A retrospective review of all pelvic ring injuries based on Abbreviated Injury Scale (AIS) codes was performed at a single level I academic trauma center from July 2010 to June 2013. Thin-section computed tomography (CT) scans in all patients were reviewed and classified using AIS codes: posterior arch intact, incomplete posterior arch, or complete posterior arch. The surgeon was blinded to the AIS code from the registry. These CT-based classifications were then compared with the pelvic ring injury codes designated in the trauma registry for each patient to evaluate agreement. Results: Two hundred thirty-five patients with a mean age of 42 years had pelvic ring injuries in our registry. The agreement between trauma registry codes and CT reclassification was 24% in the intact group, 43% in the incomplete group, and 59% in the complete group. Using only the trauma registry codes, injuries were underclassified in 48% of the incomplete group and 76% of the intact group. Conclusions: Many pelvic ring injuries are miscoded and misclassified in the NTDB. The etiology of this misclassification is unclear, but any research data mined from these databases should be regarded cautiously.

Fragility Fractures of the Pelvis: New Approaches to Classification and Management

Purpose of ReviewThe purpose of the present article is to review the new approaches to classification and management of fragility fractures of pelvis.Recent FindingsFragility fractures of the pelvis (FFPs) account for approximately 7% of fragility fractures and are increasing in incidence due to the aging population, an increase in life expectancy, and a more active life-style. The FFPs are characterized by isolated bone disruption and are generally more stable than high-energy pelvic ring fractures due to intact ligaments. Due to differences in the degrees of instability, the traditional classification systems (Tile or Young and Burgess) for acute pelvic ring injuries from high-energy trauma may not be applicable to FFPs. Through a classification system based on fracture location and the degree of instability, FFPs can be appropriately managed with either conservative treatment or surgery.SummaryFragility fractures occur in patients with primary or secondary osteoporosis from low-energy trauma or no known trauma. FFPs are different from high-energy pelvic fractures in the degree of instability and the approach to fracture management. Diagnosis of FFPs requires a high index of suspicion and the early use of CT or MRI to prevent long-term complications.

The Wrist: Athletic TFCC Injuries

Purpose of Review The purpose of this article is to illustrate MRI examples of acute triangular fibrocartilage complex (TFCC) injuries following the Palmer classification, including subtypes of the acute traumatic injuries originally described. In the discussion of these athletic TFCC injuries, recent studies and references are discussed with regard to implications in diagnosis and treatment. The article also reviews the role of ulnar abutment in degenerative injury to the TFCC and surgical approaches to correction.Recent FindingsRecent findings regarding the role of the TFCC in distal radioulnar joint stability (DRUJ) and the importance of MRI in preoperative planning of the wrist are reviewed. New studies emphasizing the importance of repair of partial tears of the foveal attachment of the TFCC, the association of TFCC tears with distal radius fractures, and wafer procedures are also discussed.SummaryInjuries of the triangular fibrocartilage complex (TFCC) are commonplace in athletes across multiple sports. The TFCC acts to cushion forces transmitted from the ulnar side of the wrist to the upper extremity. Athletic activities tend to deliver an increased axial load and greater twisting motion upon the wrist. The Palmer classification system for TFCC injuries was first introduced in 1989, but is still used for both acute traumatic and degenerative injuries of the TFCC. MRI plays a pivotal role in diagnosing and classifying athletic injuries of the TFCC, helping guide orthopedists and hand surgeons in caring for patients with ulnar-sided wrist pain.

Criteria for level 1 and level 2 trauma codes: Are pelvic ring injuries undertriaged?

AIM To determine the association of unstable pelvic ring injuries with trauma code status. METHODS A retrospective review of all pelvic ring injuries at a single academic center from July 2010 to June 2013 was performed. The trauma registry was used to identify level 1 and level 2 trauma codes for each injury. The computed tomography scans in all patients were classified as stable or unstable using the Abbreviated Injury Scale. Pelvic injury classifications in level 1 and level 2 groups were compared. Patient disposition at discharge in level 1 and level 2 groups were also compared. RESULTS There were 108 level 1 and 130 level 2 blunt trauma admissions. In the level 1 group, 67% of pelvic injuries were classified as stable fracture patterns and 33% were classified as unstable. In the level 2 group, 62% of pelvic injuries were classified as stable fracture patterns and 38% were classified as unstable. level 1 trauma code was not associated with odds of having an unstable fracture pattern (OR = 0.83, 95%CI: 0.48-1.41, P = 0.485). In the level 1 group with unstable pelvic injuries, 33% were discharged to home, 36% to a rehabilitation facility, and 32% died. In the level 2 group with unstable pelvic injuries, 65% were discharged to home, 31% to a rehabilitation facility, and 4% died. For those with unstable pelvic fractures (n = 85), assignment of a level 2 trauma code was associated with reduced odds of death (OR = 0.07, 95%CI: 0.01-0.35, P = 0.001) as compared to being discharged to home. CONCLUSION Trauma code level assignment is not correlated with severity of pelvic injury. Because an unstable pelvis can lead to hemodynamic instability, these injuries may be undertriaged.

The "winking owl" sign.

Interpreting an abdominal radiograph entails more than just looking at the bowel gas pattern, or for free air. The skeletal structures can offer valuable clues to pathology. A ‘‘winking owl’’ (Fig. 1) metaphorically describes an absent vertebral body pedicle as seen on a standard frontal abdominal view (Fig. 2) [1]. With the vertebral body as the owl’s head, the absent pedicle represents the owl’s ‘‘winked’’ eye, the normal contralateral pedicle represents the open eye, and the vertebral spinous process represents the owl’s beak [2]. The sign typically indicates skeletal metastases involving the posterior vertebral body, with the lytic process in the pedicle accounting for the ‘‘wink’’ [1, 3, 4]. Lysis of over 50% of the trabecular bone within a vertebral body must occur before the process becomes evident radiographically; however, cross-sectional imaging affords earlier detection and more complete characterization (Figs. 3, 4) [5].

Clinical and Research Applications of Bone Mineral Density Examinations

For over a quarter of a century, various types of examinations measuring bone mineral density (BMD) yielded essential information about bone health and fracture risk and have made a significant impact on osteoporosis research as well as on patient management. Yet care must be exercised when interpreting the results of these, “densitometric,” examinations, as pitfalls are common and may be overlooked. Bone densitometric techniques allow quantitative measurement of BMD and are commonly divided into central and peripheral. Central methods allow measurement of BMD in the spine and proximal femur and include dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). Peripheral methods allow measurement of BMD in the phalanges, forearm, tibia, or calcaneus and include peripheral dual X-ray absorptiometry (pDXA) and peripheral quantitative computed tomography (pQCT). Although it does not measure BMD, quantitative ultrasound (QUS) is often included with peripheral methods. This chapter reviews these techniques and puts into perspective the utility of each of these measurements for evaluating bone health and fracture risk.