Ultrasound-guided costovertebral joint injection-technique description and fluoroscopy and computerized tomography combined controlled cadaveric feasibility study.

OBJECTIVES: To describe and assess the feasibility of an ultrasound-guided technique for intra-articular injection of the costovertebral joints, in an unembalmed cadaveric specimen, utilizing fluoroscopy and cone beam computerized tomography for confirmation of contrast spread and needle tip position, respectively. METHODOLOGY: A single unembalmed cadaveric specimen was obtained. A single interventionist performed the placement of the needles under ultrasound guidance. Contrast dye was then injected through each of the needles under real-time fluoroscopy. Finally, the specimen was submitted to a cone beam computerized tomography with 3-dimensional acquisition and multiplanar reformatting to assess final needle tip position relative to the costovertebral joints. RESULTS: In total, 18 spinal needles were placed under ultrasound guidance. Fluoroscopy showed 4 distinct patterns of contrast spread: intra-articular in the costovertebral joint (13 levels in total), epidural (1 level), intra-articular in the facet joint of the target level (3 levels), and undetermined (1 level). Cone-beam computerized tomography confirmed 13 out of 18 needles to be adequately placed in the costovertebral joints (72% of the total) and 5 out of the 18 needles to be misplaced: 3 needles were placed in the facet joint of the target level, and 2 needles were placed in the epidural space. CONCLUSIONS: This study suggests that, when performed by experienced interventionists, this technique has an accuracy rate of 72%. Further studies are warranted before these results can be extrapolated to daily clinical practice.

Radiologists should use the hip-knee-ankle angle rather than the mechanical axis deviation to describe knee alignment.

OBJECTIVE: Preoperative and postoperative coronal knee alignment is an important predictor of total knee arthroplasty (TKA) failure. Radiologists often report the mechanical axis deviation (MAD) rather than hip-knee-ankle angle (HKAA) to describe coronal knee alignment. The aim of this study is to evaluate (i) how well the MAD predicts the HKAA; (ii) if patient height and sex affect the performance of the MAD; and (iii) if the MAD could be measured faster than the HKAA. MATERIALS AND METHODS: Two hundred patients undergoing hip-to-ankle radiographs for TKA planning were retrospectively reviewed. The MAD and HKAA were measured using previously published methods by the Visage picture archiving and communication systems (PACS) tools. Receiver operator characteristic (ROC) curves were used to evaluate the performance of the MAD to predict HKAA by gender and height. The performance of a linear model was used to predict HKAA from MAD in a prospectively collected cohort of 40 patients. Paired t tests were used for the comparison of time measurement in MAD and HKAA in this cohort. RESULTS: MAD strongly correlated with HKAA (r = 0.99, p < 0.001); however, the performance of MAD differed by height (p = 0.005) and sex (p < 0.001). There was no significant difference in the time taken to measure HKAA versus MAD (p > 0.05). CONCLUSION: HKAA should be used instead of the MAD because it is more clinically relevant and takes the same amount of time to be measured.

Radiology-pathology correlation for bone and soft tissue tumors or tumor-like masses: single institutional experience after implementation of a weekly conference.

OBJECTIVES: To determine the frequency of non-diagnostic and discordant results from bone and soft tissue biopsies performed at our institution over a 3-year period and to investigate whether implementation of a weekly musculoskeletal radiology-pathology correlation conference decreased the time to appropriate patient management in cases of discordance. METHODS: Consecutive image-guided core needle biopsy results obtained over a 12 month period of time were reviewed in a retrospective fashion. Following implementation of the correlation conference, subsequent consecutive image-guided core needle biopsy results obtained over a 26 month period of time were reviewed in a prospective fashion. For non-diagnostic and discordant cases, the time in days from date of availability of the biopsy result to date of documentation of a specific follow-up action plan was recorded. RESULTS: Diagnostic yield was 96.5% and 94.9% for the retrospective and prospective periods, respectively. There were four discordant results in the retrospective cohort (1.7%) and seven discordant results in the prospective cohort (2.1%). Following implementation of the weekly correlation conference, there was significant decrease (p < 0.05) in median time from a discordant biopsy result to follow-up action plan. There were no unnecessary surgeries, litigation, or other unfavorable consequences in either cohort. CONCLUSION: Image-guided core needle biopsies of bone and soft tissue provide high diagnostic yield, often with specific diagnoses. The statistically significant decrease in number of days to follow-up action plan for discordant results suggests radiology-pathology review has a positive impact on patient care. Subjective benefits from communication and educational standpoints are also noteworthy.

Epithelioid schwannoma: imaging findings on radiographs, MRI, and ultrasound.

Epithelioid schwannoma is an uncommon benign peripheral nerve sheath tumor, with distinct morphological and pathological features. To our knowledge, the imaging features of epithelioid schwannoma have not been described. In this case report, we describe the imaging findings of a pathologically proven case of epithelioid schwannoma presenting as a slowly growing painless mass near the ankle. The MR imaging signs commonly associated with conventional schwannoma were absent. On correlative radiographs, there were intra-tumoral calcifications. Radiographs are an essential tool in the imaging evaluation of soft-tissue masses. Knowledge of soft-tissue tumor types that can be associated with intra-tumoral calcifications is helpful in honing the differential diagnosis.

Preoperative radioactive seed localization of nonpalpable soft tissue masses: an established localization technique with a new application.

OBJECTIVE: To describe the technique of iodine125 (I125) seed deployment into nonpalpable soft tissue masses under direct ultrasound (US) or CT guidance for intraoperative localization. MATERIALS AND METHODS: Patients considered candidates for radioactive seed localization (RSL) based on advanced imaging findings underwent an ultrasound examination of the area of concern to verify sonographic visualization of the targeted mass. If the mass was not visible sonographically, CT was used for guidance. Patients were scheduled for surgery 1-4 days after seed implantation. Intraoperative frozen section pathological analysis was performed on all patients. Operative time, specimen volume, intraoperative margin status, and final margin status were recorded. Following the surgery, patients and surgeons completed satisfaction surveys. RESULTS: Ten patients underwent seed placement between 1 and 4 days prior to surgery. All patients had successful surgical resection of the targeted mass with removal of all implanted radioactive seed(s). There was no seed migration. Intraoperative frozen-section margins were negative (>2 mm) in 6/10 patients. Final surgical margins were negative in 9/10 patients. The patient with a positive margin at final pathology did not undergo further resection due to the benign nature of the mass. Patient and surgeon satisfaction survey results were highly positive. All four surgeons reported a strong preference for seed localization over wire localization. CONCLUSIONS: RSL is an effective, reliable, and safe technique for preoperative localization of nonpalpable soft tissue masses and yields high patient and surgeon satisfaction.

Diffuse skeletal muscle metastases from sacral chordoma.

Chordomas are rare, slow-growing tumors arising from cellular remnants of the notochord. They account for 1-4% of primary malignant bone tumors and usually occur in the axial skeleton, most commonly the sacrum. Although typically locally recurrent, chordoma metastasis rates as high as 10-42% have been reported. While spread to multiple organ systems has been documented, metastatic disease to skeletal muscle is extremely rare. We present a case of extensive, multifocal skeletal muscle metastases developing in the setting of recurrent sacral chordoma. Our literature search found only one additional case of metastatic chordoma to a single skeletal muscle.

Sclerosing variant of well-differentiated liposarcoma: relative prevalence and spectrum of CT and MRI features.

OBJECTIVE: The purpose of this study was to determine the relative prevalence of the sclerosing variant of well-differentiated liposarcoma at one institution and to elucidate the CT and MRI characteristics of this subtype of well-differentiated liposarcoma. MATERIALS AND METHODS: A retrospective computerized search was conducted to calculate the relative prevalence of the sclerosing variant of well-differentiated liposarcoma among all well-differentiated liposarcoma subtypes at one institution. The MRI and CT features of a total of 19 cases of pathologically proven sclerosing variant of well-differentiated liposarcoma were evaluated (seven identified from the study institution database and 12 cases contributed by other institutions). RESULTS: The cases of a total of 36 patients with well-differentiated liposarcoma were identified in the pathology database; six (17%) cases had evidence of dedifferentiation. Seven (19%) cases of sclerosing variant of well-differentiated liposarcoma were identified. Of these, three (43%) had evidence of dedifferentiation. On images, the sclerosing variant of well-differentiated liposarcoma typically presented as a large (average, 16.6 cm) well-circumscribed heterogeneous mass most commonly situated in the retroperitoneum (58%). Sixteen of the 19 tumors evaluated (84%) had predominantly well-circumscribed margins. Tumor composition ranged from predominantly fatty to entirely devoid of macroscopic fat; only three (16%) were composed of more than 75% fat. Variable amounts of nonlipomatous elements were identified in all cases. Enhancement of these elements was evident at CT or MRI in all 14 cases in which enhancement could be reliably assessed. CONCLUSION: The sclerosing variant of well-differentiated liposarcoma should be included in the differential diagnosis of any well-circumscribed lipomatous mass containing variable amounts of nonlipomatous elements, particularly when located in the retroperitoneum. Unlike other subtypes of well-differentiated liposarcoma, the sclerosing variant is less likely to be composed predominantly of fat and may be associated with an increased propensity for dedifferentiation.

Benign synovial tumors and proliferative processes.

This article discusses several benign tumors and proliferative processes of the synovium including giant cell tumor of the tendon sheath, pigmented villonodular synovitis, synovial chondromatosis, lipoma arborescens, and synovial hemangioma, lipoma, and fibroma. We review the clinical features and imaging characteristics of each entity, with a special focus on the unique imaging findings that can enable a confident diagnosis or a limited differential diagnosis.

A Pilot Study of Intralesional Injection of Triamcinolone Acetonide for Desmoid Tumors: Two-Year Outcomes.

PURPOSE: The purpose of this pilot study was to examine the clinical efficacy and safety of serial triamcinolone injections for the treatment of desmoid tumors. PATIENTS AND METHODS: Nine patients were enrolled into this prospective study and underwent three serial ultrasound-guided triamcinolone injections (120 mg) at 6-week intervals. MRI was compared at baseline and every 6 months, out to 24 months. Safety and tolerability were assessed by clinical evaluation and questionnaires, including the 12-item short form survey (SF-12), visual analog scale (VAS), and desmoid patient-reported outcome (PRO) tool. RESULTS: At 24 months, 8 (88.9%) patients demonstrated a reduction in the volume of their tumor while 1 (11.1%) enlarged. Median tumor volume change was -26.9% (-81.1% to 34.6%; P = 0.055) All 9 tumors remained stable based on World Health Organization criteria, whereas 2 (22.2%) demonstrated partial response based on RECIST. There was a significant decrease in the tumor:muscle postcontrast mean signal intensity ratio at 6 months (P = 0.008) and 24 months (P = 0.004). There was a similar decrease in the tumor:muscle T2 mean signal intensity ratio at 24 months (P = 0.02). We found no difference in the SF-12 and VAS scores, but there were significant improvements in the desmoid PRO. CONCLUSIONS: Treatment of desmoid tumors with serial triamcinolone injections appears safe and well tolerated by patients, with a 22% partial response based on RECIST. Further research is needed to confirm our results and determine factors predictive of response.

Shoulder Osteoarthritis.

Glenohumeral osteoarthritis has proven to be a major contributor to shoulder joint pain and dysfunction in the elderly. There are several conditions about the shoulder that contribute to the development of glenohumeral osteoarthritis, which includes traumatic injuries, rotator cuff pathology, glenohumeral instability, glenoid dysplasia, and osteonecrosis. When glenohumeral osteoarthritis pain is refractory to conservative treatment, intra-articular injections and surgery can be performed. The radiologist should be aware of the varying types of shoulder arthroplasties, what preoperative findings influence that decision and the expected postoperative appearance of the differing components.

ACR Appropriateness Criteria® Primary Bone Tumors.

Although primary bone tumors are relatively uncommon, appropriate imaging evaluation is essential when they are suspected or incidentally detected. In almost all cases, radiographs are the most appropriate initial imaging study for screening and characterization of primary bone tumors. Radiographs often provide sufficient information for diagnosis and to guide the treating clinician. However, when conventional radiographs alone are inadequate, they still often guide the selection of the most appropriate next step for advanced imaging. MRI and CT are typically the most appropriate next step. MRI provides excellent soft-tissue contrast allowing for evaluation of the tissue composition (such as fat, hemorrhage, fluid levels) and anatomic extent of bone tumors. CT provides complementary information, with its ability to detect subtle matrix mineralization or periosteal reaction that may not be seen on radiographs or MRI. This publication focuses on six common variants to guide diagnosis and management of primary bone tumors. In addition to conventional radiographs, appropriate use of MRI, CT, PET/CT, bone scan, and ultrasound are discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Pediatric FDG PET/CT: Physiologic uptake, normal variants, and benign conditions [corrected].

Ewing sarcoma family tumors account for approximately 3% of all pediatric cancers, making them the second most common bone malignancies in children and adolescents. Advances in the treatment of localized disease have dramatically prolonged the survival of patients in whom Ewing sarcoma is diagnosed, but the prognosis for patients with metastatic or recurrent disease remains poor. Radiologic evaluation of Ewing sarcoma can help (a) detect and accurately assess the extent of disease prior to treatment, (b) determine whether metastatic or recurrent disease is present, and (c) monitor therapy response. Standard imaging evaluation of bone and soft-tissue sarcomas typically consists of conventional radiography, magnetic resonance (MR) imaging, computed tomography (CT), and bone scintigraphy. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) provides unique information with regard to the biologic activity of Ewing sarcomas. It represents a noninvasive means of estimating histologic tumor grade and can be used to detect progression or regression of disease prior to anatomic imaging. Such information can be used to optimize staging, restaging, and assessment of therapy response. Functional imaging with FDG PET can also potentially help predict patient prognosis both before and after neoadjuvant therapy. FDG PET does have inherent limitations that must be acknowledged to avoid potential diagnostic pitfalls and is optimally used in combination with correlative anatomic imaging modalities such as CT and MR imaging. Nevertheless, FDG PET provides unique physiologic information that often has important clinical implications.

Quantitative T2 MRI Mapping and 12-Month Follow-up in a Randomized, Blinded, Placebo Controlled Trial of Bone Marrow Aspiration and Concentration for Osteoarthritis of the Knees.

OBJECTIVE: Bone marrow aspiration and concentration (BMAC) is becoming a more common regenerative therapy for musculoskeletal pathology. In our current pilot study, we studied patients with mild-to-moderate bilateral knee osteoarthritis, compared pain at 12-month follow-up between BMAC-injected and saline-injected knees, and examined cartilage appearance measured by magnetic resonance imaging (MRI) T2 quantitative mapping. DESIGN: Twenty-five patients with mild-to-moderate bilateral osteoarthritic knee pain were randomized to receive BMAC into one knee and saline placebo into the other. Bone marrow was aspirated from the iliac crests, concentrated in an automated centrifuge, combined with platelet-poor plasma for knee injection, and compared with saline injection into the contralateral knee. Primary outcome measures were T2 MRI cartilage mapping at 6-month and Visual Analog Scale and Osteoarthritis Research Society International Intermittent and Constant Osteoarthritis Pain scores and radiographs at 12-month follow-up. RESULTS: Constant, intermittent, and overall knee pain remained significantly decreased from baseline at 12-month follow-up (all P ⩽ 0.01), with no apparent difference between BMAC- and saline-treated knees (all P ⩾ 0.54). A similar significant increase from baseline to 12-month follow-up regarding quality of life was observed for both BMAC- and saline-treated knees (all P ⩽ 0.04). T2 quantitative MRI mapping showed no significant changes as a result of treatment. CONCLUSIONS: BMAC is safe to perform and relieves pain from knee arthritis but showed no superiority to saline injection at 12-month follow-up. MRI cartilage sequences failed to show regenerative benefit with single BMAC injection. The mechanisms of action that led to pain relief remain unclear and warrant further studies.

Postoperative imaging of the total ankle arthroplasty.

Promising results reported with currently available total ankle arthroplasty designs have led to an increased use of such devices as an alternative to ankle arthrodesis. Despite recent improvements in implant design and surgical technique, complications associated total ankle arthroplasty devices continue to be reported. Postoperative evaluation of total ankle arthroplasties relies on a combination of clinical and radiologic assessment. Familiarity with commonly used current total ankle arthroplasty devices and appropriate postoperative imaging techniques is imperative for effective characterization of the expected postoperative imaging appearances of such devices and facilitating detection of potential postoperative complications.

Postoperative evaluation of the total ankle arthroplasty.

OBJECTIVE: The purpose of this article is to review the basic design features of second-generation total ankle arthroplasty components and to illustrate the normal and abnormal postoperative imaging features associated with such devices. The usefulness of CT in postoperative evaluation will be highlighted. CONCLUSION: Postoperative evaluation of the total ankle arthroplasty necessitates a familiarity with the various designs currently in use. Radiography serves as an integral component in the postoperative evaluation of such devices, with CT offering further characterization of radiographic abnormalities.

Magnetic resonance imaging to detect vesico-symphyseal fistula following robotic prostatectomy

Pubic complications following radical prostatectomy are rare. Osteitis pubis typically presents with symptoms related to irritation of the pubic rami including pain with ambulation and adduction of the leg. A 60-year-old male with prostatic adenocarcinoma underwent uneventful robotic assisted laparoscopic prostatectomy. The patient noted the onset of severe pubic pain exacerbated by ambulation approximately one month post-surgery. An abdominal/pelvic CT scan was negative for acute pathology. Due to continued discomfort, a multiplanar MRI of the pelvis was performed with and without intravenous contrast material (20 ml Omniscan). The MRI demonstrated irregularity of the bladder base and proximal urethra with a fistulous tract extending anteriorly in direct communication with the pubic symphysis joint space. Vague periarticular marrow edema-like signal and enhancement at the pubic symphysis was thought to represent osteitis pubis. The patient's symptoms resolved after one month of urethral catheter drainage, intravenous antibiotics, and anti-inflammatory therapy.