Gastrointestinal Stromal Tumors: Imaging Features Before and After Treatment.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, with most occurring in the stomach. GISTs may present with clinical symptoms (eg, gastrointestinal bleeding) or may be found incidentally at surgery, endoscopy, or imaging. At initial staging, GISTs often appear as well-circumscribed, round, solid masses. Small tumors may appear solid, whereas larger tumors may demonstrate central areas of necrosis. At follow-up imaging, decreasing tumor attenuation at computed tomographic indicates treatment response even in the setting of stable tumor size. Localized tumors are treated with resection. Imatinib mesylate, a tyrosine kinase inhibitor, is typically prescribed for metastatic disease and increasingly in a neoadjuvant role before resection. Imaging plays a key role in the identification of GISTs, evaluation of tumor extent and presence or absence of metastatic disease, and in assessing response to therapy.

Osseous injuries of the foot: an imaging review. Part 3: the hindfoot.

Injuries to the foot are a common cause for presentation to the emergency department, and imaging is often used to aid in the diagnosis. The foot can be divided into three distinct anatomic regions: the forefoot, midfoot and hindfoot. Our manuscripts comprise a three-part imaging review in which we address the use of radiography as well as advanced imaging modalities. We provide pearls to radiographic interpretation and discuss prognostic implications and classification systems. Part 1 addresses forefoot injuries, part 2 reviews midfoot injuries and part 3 covers the hindfoot.

Osseous injuries of the foot: an imaging review. Part 1: the forefoot.

Injuries to the foot are a common cause for presentation to the ED, and imaging is often used to aid in the diagnosis. The foot can be divided into three distinct anatomical regions: the forefoot, midfoot and hindfoot. Our manuscripts comprise a three-part imaging review in which we address the use of radiography as well as advanced imaging modalities. We provide pearls to radiographic interpretation and discuss prognostic implications and classification systems. Part 1 addresses forefoot injuries, part 2 reviews midfoot injuries and part 3 covers the hindfoot.

Osseous injuries of the foot: an imaging review. Part 2: the midfoot.

Injuries to the foot are a common cause for presentation to the emergency department (ED), and imaging is often used to aid in the diagnosis. The foot can be divided into three distinct anatomic regions: the forefoot, midfoot and hindfoot. Our manuscripts comprise a three-part imaging review in which we address the use of radiography as well as advanced imaging modalities. We provide pearls to radiographic interpretation and discuss prognostic implications and classification systems. Part 1 addressed forefoot injuries, Part 2 reviews midfoot injuries and Part 3 covers the hindfoot.

Masses of the hand and wrist, a pictorial review.

The majority of hand and wrist soft tissue and osseous masses are benign, commonly presenting as palpable or incidentally detected lesions. When analyzing such a mass, one of the radiologist's most important objectives is to determine if the lesion requires a biopsy. In this review, the imaging appearances of 14 different types of masses are presented with pathologic correlation. An understanding of the histologic findings can provide radiologists with a more comprehensive understanding of the magnetic resonance imaging appearances and may ultimately help to reduce the cost, morbidity, and anxiety associated with the management of patients presenting with masses of the hand and wrist.

Sacrum and Coccyx Radiographs Have Limited Clinical Impact in the Emergency Department.

OBJECTIVE: The purpose of this study was to determine the yield and clinical impact of sacrum and coccyx radiographs in the emergency department (ED). MATERIALS AND METHODS: Consecutive sacrum and coccyx radiographs obtained in the EDs of four hospitals over a 6-year period were categorized as positive for acute fracture or dislocation, negative, or other. Five follow-up metrics were analyzed: follow-up advanced imaging in the same ED visit, follow-up advanced imaging within 30 days, new analgesic prescriptions, clinic follow-up, and surgical intervention within 60 days. RESULTS: Sacrum and coccyx radiographs from 687 patients (mean age, 48.1 years; 61.6% women and 38.4% men) obtained at level-1 (n = 335) and level-2 (n = 352) trauma centers showed a positivity rate of 8.4% ± 2.1% (n = 58/687). None of the 58 positive cases had surgical intervention. At the level-1 trauma centers, there was no significant association between sacrum and coccyx radiograph positivity and analgesic prescription or clinical follow-up (p = 0.12; odds ratio [OR], 2.3; 95% CI, 0.81-6.20). At the level-2 trauma centers, 97.1% (n = 34/35) of patients with positive sacrum and coccyx radiographs received analgesic prescriptions or clinical referrals, whereas negative cases were at 82.9% (OR, 7.0; 95% CI, 0.94-52.50). Of all cases, 5.7% (n = 39) and 4.3% (n = 29) had advanced imaging in the same ED visit and within 30 days, respectively. Sacrum and coccyx radiography results had no significant correlation with advanced imaging in the same ED visit (level-1, p = 0.351; level-2, p = 0.179). There was no significant difference in 30-day advanced imaging at the level-1 trauma centers (p = 0.8), but there was at the level-2 trauma centers (p = 0.0493). CONCLUSION: ED sacrum and coccyx radiographs showed a low positivity rate and had no quantifiable clinical impact. We recommend that sacrum and coccyx radiographs be eliminated from ED practice and patients treated conservatively on the basis of clinical parameters.

Benign and malignant tumors of the foot and ankle.

Pain and focal masses in the foot and ankle are frequently encountered and often initiate a workup including imaging. It is important to differentiate benign lesions from aggressive benign or malignant lesions. In this review, multiple examples of osseous and soft tissue tumors of the foot and ankle will be presented. Additionally, the compartmental anatomy of the foot and ankle will be discussed in terms of its relevance for percutaneous biopsy planning and eventual surgery. Finally, a general overview of the surgical management of benign, benign aggressive and malignant tumors of the foot and ankle will be discussed.

A systematic, multimodality approach to emergency elbow imaging.

The elbow is a complex synovial hinge joint that is frequently involved in both athletic and nonathletic injuries. A thorough understanding of the normal anatomy and various injury patterns is essential when utilizing diagnostic imaging to identify damaged structures and to assist in surgical planning. In this review, the elbow anatomy will be scrutinized in a systematic approach. This will be followed by a comprehensive presentation of elbow injuries that are commonly seen in the emergency department accompanied by multimodality imaging findings. A short discussion regarding pitfalls in elbow imaging is also included.

MRI of the hand and fingers.

Injuries of the hand and fingers occur commonly in professional athletes as well as weekend warriors. Magnetic resonance imaging plays a vital role in the evaluation of these injuries for accurate diagnosis, preoperative planning, potential complication, and follow-up during rehabilitation. A detailed analysis of these smaller structures necessitates optimal imaging quality coupled with comprehensive knowledge of the imaging anatomy. In this article, we discuss technical aspects and normal anatomy of hand and fingers imaging on magnetic resonance imaging. This section is followed by discussion of soft tissue and osseous injuries including mechanism of injury, clinical presentation, and imaging findings.

Diagnostic utility of MRI and MR arthrography for detection of ligamentum teres tears: a retrospective analysis of 187 patients with hip pain.

OBJECTIVE: The purpose of this study was to compare the diagnostic utility of MRI and MR arthrography for ligamentum teres tears in patients with hip pain. MATERIALS AND METHODS: This is a retrospective study involving 187 patients who underwent MRI or MR arthrography for hip pain. This study included 103 male and 84 female patients with average age of 39 years. Three experienced musculoskeletal radiologists reviewed the MRI and MR arthrography studies to assess the ligamentum teres tears. The criteria for diagnosing normal or abnormal (i.e., ligament), partial or degenerative or complete tear of ligamentum teres were defined on the basis of several imaging characteristics. The MRI and MR arthrography results were correlated with arthroscopy, which served as the reference standard. Statistical analysis was performed to calculate the diagnostic yield, diagnostic accuracy, and diagnostic performance of MRI and MR arthrography in detecting partial or degenerative and complete ligamentum teres tears. Overall comparative performance of MRI and MR arthrography was assessed using Kruskal-Wallis test. RESULTS: For partial ligamentum teres tears, MRI showed lower sensitivity, specificity, and positive predictive value (0.41, 0.75, and 0.32, respectively) as compared to MR arthrography (0.83, 0.93, and 0.76, respectively), whereas the negative predictive value of MRI (0.82) was comparable to that of MR arthrography (0.95). No statistically significant difference (p < 0.05) could be identified between MRI and MR arthrography for diagnosing complete ligamentum teres tears. CONCLUSION: Hip MRI is equally suited for diagnosis of complete ligamentum teres tears when compared with MR arthrography. By contrast, for partial or degenerative ligamentum teres tears, MR arthrography offers the advantage of better arthroscopic correlation.

Radiographic evaluation of INBONE total ankle arthroplasty: a retrospective analysis of 30 cases.

OBJECTIVES: The objectives of this work were to retrospectively describe the radiographic assessment of INBONE total ankle arthroplasty in 30 patients using validated linear and angular measurements and to correlate these findings with the final surgical outcome over a 2-year follow-up period. MATERIALS AND METHODS: Thirty consecutive patients (21 females, nine males; mean age, 64.8 years) underwent INBONE total ankle arthroplasty during 2007-2011. After IRB approval, a retrospective pre- and post-operative radiographic analysis was performed using validated linear and angular measurements. The pre- and post-operative assessment included the tibial angle, talar angle, tibial slope, and coronal deformity. Post-operative measurements also included the talocalcaneal angle, joint space height, talar height, lateral tibial component angle, lateral talar component angle, and anteroposterior tibial component angle. The post-operative bone loss, subluxation, positioning, and subsidence were also assessed. Statistical analysis was performed using two-sample t test and Fisher's exact test. RESULTS: Out of 30 patients, 23 had a successful clinical outcome with intact prosthesis at a 2-year follow-up. The only variables with significant correlation (p < 0.05) to the post-surgical outcome were the lateral talar component angle (p = 0.002) and the mean difference between pre- and post-operative tibial slope (p = 0.001). The coronal deformity had significant mean difference between pre- and post-operative values (p < 0.001); however, it lacked a significant correlation to the final surgical outcome. None of the categorical variables had a significant correlation with post-surgical outcome. CONCLUSIONS: In our retrospective study, only the lateral talar component angle and the mean difference between the pre- and post-operative tibial slope had significant correlation with post-surgical outcome in INBONE ankle arthroplasty. These measurements may be helpful in radiographic assessment of the INBONE ankle arthroplasty.

Magnetic resonance imaging of anatomical variations in the knee. Part 2: miscellaneous.

Magnetic resonance imaging is the modality of choice for investigation of internal derangement of the knee. The reporting radiologist must be familiar with both normal anatomy and anatomical variants within the knee, in order to avoid mis-diagnosis, over-investigation and unnecessary intervention. This article reviews the recognised anatomical variants of the non-ligamentous/musculotendinous structures of the knee, their anatomy, incidence and typical appearances on MRI.

Magnetic resonance imaging of anatomical variations in the knee. Part 1: ligamentous and musculotendinous.

Magnetic resonance imaging (MRI) is now the modality of choice for the investigation of internal derangement of the knee. Technological advances, including the wider availability of stronger magnets and new sequences, allows improved visualisation of smaller structures. Normal variants must be recognised as such, so that both over-investigation and mis-diagnosis are avoided. This article reviews both the well-recognised and the less common ligamentous and musculotendinous anatomical variants within the knee and illustrates their imaging characteristics on MRI.

Imaging of impingement lesions in the ankle.

Ankle impingement and instability are well-recognized complications of ankle sprain. Ankle impingement is an important cause of chronic ankle pain in active populations, particularly in the professional athlete. Depending on anatomical location and the structures involved, impingement syndromes are classified into anterolateral, anterior, posterior, posteromedial, and anteromedial types. Clinically, impingement syndromes are characterized by painful limitation of full-ankle movement. Ankle impingement results from repetitive subclinical trauma due to overuse injuries, which, in the subacute or chronic situation, lead to abnormal osseous and soft-tissue thickening within the ankle joint. Various imaging techniques can be used in the diagnosis of ankle impingement. Usually, radiography is the initial imaging technique performed to rule out bony trauma and identify potential anatomical bony abnormalities. Use of computed tomography and isotope bone scanning is largely superseded by magnetic resonance imaging, although with variable sensitivity and specificity. Arthrographic techniques, using computed tomography or magnetic resonance, are useful for exquisite demonstration of capsular recesses and synovial abnormalities. Imaging-guided injection techniques can be used in the management of impingement for pain ablation and to aid clinical diagnosis, especially in hind foot pain.

Percutaneous treatment of insufficiency fractures : principles, technique and review of literature.

Insufficiency fractures of the pelvis, sacrum, spine, and long bones are painful, debilitating, and are common consequences of osteoporosis. Conventional treatment for these fractures varies from conservative therapy to surgery with plate and screw fixation. The former fails to address the underlying problem of fracture and frequently does not alleviate symptoms, while the latter is invasive and not always possible in older populations with low bone density and numerous co-morbidities. Osseous augmentation with polymethylmethacrylate (PMMA) has been used for over two decades to treat fractures related to osteoporosis, but has not been commonly used to treat fractures outside of the vertebral bodies. Osseous augmentation with PMMA is an image-guided procedure and various techniques have been utilized to treat fracture in different locations. We describe various techniques for image-guided osseous augmentation and treatment of insufficiency fractures with bothPMMA and allograft bone for fractures of the pelvis including sacrum, acetabulum, pubic symphysis, pubic rami ilium; appendicular skeleton including distal radius, proximal femur, and vertebral body. We also describe the potential risks and complications associated with percutaneous treatment of insufficiency fractures and techniques to avoid the pitfalls of the various procedures. We will present the process for patient follow-up and data regarding the pre- and postprocedure pain response in patients undergoing treatment for pelvic insufficiency fractures.

Imaging-guided percutaneous biopsy of pathologic fractures: a retrospective analysis of 129 cases.

OBJECTIVE: The purpose of our study was to determine the diagnostic performance of imaging-guided percutaneous needle core biopsy and the factors associated with a nondiagnostic biopsy in patients with a pathologic fracture of the appendicular skeleton. MATERIALS AND METHODS: A retrospective audit was performed of 129 consecutive patients presenting with a pathologic fracture. All patients underwent percutaneous needle core biopsy using CT (n = 98), fluoroscopy (n = 15), or ultrasound (n = 16) guidance. In all cases, either MRI or CT was available before biopsy to assess the presence and degree of the extraosseous tumor mass. The resulting sample was classified as diagnostic (group 1) or nondiagnostic (group 2) on histopathologic study. Diagnostic performance was evaluated on the basis of the diagnostic yield and the diagnostic accuracy, and these were related to the site of the lesion and presence or absence of an extraosseous mass. RESULTS: Ninety-nine masses (77%) were classified as group 1 and 30 (23%) as group 2. The average cross-sectional diameter of lesions in group 1 was 5.7 x 5.9 cm. Of the 30 lesions composing group 2, no soft-tissue component was identified on prebiopsy cross-sectional imaging in 27 lesions (90%), but the remaining three (10%) showed a smaller extraosseous soft-tissue component compared with the lesions in group 1. CONCLUSION: Imaging-guided core biopsy is a reliable method for obtaining a tissue diagnosis in pathologic fracture of the appendicular skeleton with a high rate of accuracy. However, those lesions that are purely intraosseous or have only very small extraosseous components are more likely to be associated with a nondiagnostic biopsy and should be considered for a primary open procedure.