T1Gd is reduced in bone marrow lesions overlying cartilage in the hip.

OBJECTIVE: Bone Marrow Lesions (BMLs) are areas in bone with high fluid signal on MRI associated with painful and progressive OA. While cartilage near BMLs in the knee has been shown to be degenerated, this relationship has not been investigated in the hip. RESEARCH QUESTION: is T1Gd lower in areas of cartilage overlying BMLs in the hip? DESIGN: 128 participants were recruited from a population-based study of hip pain in 20-49-year-olds. Proton-density weighted fat-suppressed and delayed Gadolinium Enhanced MR Imaging of Cartilage (dGEMRIC) images were acquired to locate BMLs and quantify hip cartilage health. BML and cartilage images were registered and cartilage was separated into BML overlying and surrounding regions. Mean T1Gd was measured in 32 participants with BMLs in both cartilage regions and in matched regions in 32 age- and sex-matched controls. Mean T1Gd in the overlying cartilage was compared using linear mixed-effects models between BML and control groups for acetabular and femoral BMLs, and between cystic and non-cystic BML groups. RESULTS: Mean T1Gd of overlying cartilage was lower in the BML group compared to the control group (acetabular: -105 ms; 95% CI: -175, -35; femoral: -8 ms; 95% CI: -141, 124). Mean T1Gd in overlying cartilage was lower in cystic compared to non-cystic BML subjects, but the confidence interval is too large to provide certainty in this difference (-3 [95% CI: -126, 121]). CONCLUSIONS: T1Gd is reduced in overlying cartilage in hips from a population-based sample of adults aged 20-49, which suggests BMLs are associated with local cartilage degeneration in hips.

Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Values in Hips With Bone Marrow Lesions.

OBJECTIVE: Bone marrow lesions (BMLs) are associated with painful and progressive osteoarthritis (OA). Quantitative magnetic resonance imaging (MRI) has been used to study early cartilage degeneration in knees with BML, but similar work has not been done in hips. The purpose of this study was to compare mean delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) relaxation values (T1Gd) in hips with BML to hips without BML in a population-based study. Reduced T1Gd suggests depleted glycosaminoglycan. Our hypothesis was that mean T1Gd is lower in hips with BML compared to hips without BML. METHODS: Study participants (n = 128) were recruited from a cross-sectional population-based study of people ages 20-49 years with and without hip pain. dGEMRIC and proton density (PD)-weighted MRI scans of 1 hip from each participant were used for this analysis. BMLs were identified from PD-weighted fat-suppressed images. We applied a sampling-weighted linear regression model to determine the association of the presence of BMLs with mean cartilage T1Gd (significance: P < 0.05). The model was adjusted for age, sex, body mass index (BMI), hip pain, cam/pincer deformity, and physical activity. RESULTS: Thirty-two (25%) of the 128 participants had at least 1 BML. Subjects with at least 1 BML, compared to those without, had similar weighted characteristics of age, BMI, physical activity levels, and frequency of hip pain. Mean T1Gd was 75.25 msec lower (95% confidence interval -149.69, -0.81; P = 0.048) (9%) in the BML compared to the no-BML group. CONCLUSION: Our results suggest that hips with BMLs are associated with hip cartilage degeneration early in the OA disease process.

Reducing the Volume of Low-Value Outpatient MRI Joint Examinations in Patients ≥55 Years of Age.

PURPOSE: Magnetic resonance imaging (MRI) is not beneficial in patients with joint pain and concomitant osteoarthritis (OA). We attempt to determine whether evaluation of OA via X-rays can reduce inappropriate MRI and computed tomography (CT) arthrogram use. In our jurisdiction, CT arthrograms are used as surrogate tests because of MRI wait times. MATERIALS AND METHODS: Our intervention required patients ≥55 years of age scheduled for outpatient MRI of the knee/hip/shoulder at an urban hospital to have X-rays (weight bearing when appropriate) from within 1 year. Red flags (ie, neoplasm, infection) were identified for which MRI would be indicated regardless. Through review of radiographs on picture archiving and communication system/digital media and use of the validated Kellgren-Lawrence (KL) OA scale, radiologists assessed the presence and degree of OA. A finding of significant OA (KL > 2) without red flags would preclude MRI. Monthly averages of MRI and CT arthrogram examinations were measured 33 months before and 23 months following introduction of the intervention. RESULTS: The proportion of protocoled MRI requisitions that were avoided was 21%. If extrapolated to the province of British Columbia, 2419 of 11 700 examinations could have been prevented in the past year. The average monthly number of knee/hip/shoulder MRI examinations as a percentage of total MRI examinations decreased from 4.9% to 4.3% (P < .02) following the intervention. The average monthly number of knee/hip/shoulder CT arthrogram examinations decreased from 20.6 to 12.1 (P < .0001). CONCLUSION: We were able to decrease the number of MRI and CT arthrogram examinations in patients ≥55 years of age with joint pain by implementing an evaluation for OA via recent X-ray imaging.

Rethinking the PGY-1 Basic Clinical Year: A Canadian National Survey of Its Educational Value for Diagnostic Radiology Residents.

RATIONALE AND OBJECTIVES: Recently, the relevance of the postgraduate year 1 (PGY-1) Basic Clinical Year for radiology residents has been questioned. The purpose of this study was to determine the attitude of radiologists and trainees toward this year and which clinical rotations they perceived as most valuable to clinical practice. MATERIALS AND METHODS: Following institutional review board approval, an anonymous online survey was administered to Canadian radiologists and radiology trainees. In addition to reporting demographic information, respondents were asked to rank the usefulness of individual rotations on a five-point Likert scale. To assess whether there are differences in the ratings and therefore rankings of the rotations by gender, position, and level of training, the Kruskal-Wallis one-way analysis of variance test was used with significance defined as P < .05. The Schulze method was used to rank the perceived usefulness of clinical rotations considered. RESULTS: Of the 275 respondents, 73.1% were male and 47.3% were trainees. A total of 71.3% of respondents were in favor of the basic clinical year, whereas 16.4% opposed. There was a statistically significant difference between the responses of staff radiologists and trainees, with the staff more strongly favoring the Basic Clinical Year (84.1%) than the trainees (56.9%) (P < .0001). As a whole, the respondents favored general surgery rotations as most relevant to their clinical practice (agreement rate of 48.3%). Interventional radiologists found general and subspecialty surgical rotations to be equally relevant. The rotations deemed to be "essential" were emergency medicine (48.7%) and general surgery (46.6%), and the rotations deemed to be "very useful" were orthopedics (45.8%), trauma (44.4%), neurosurgery (43.3%), neurology (42.2%), and hepatobiliary surgery (38.9%). There was no statistical difference between the respondents' choices based on their level of experience and scope of practice. CONCLUSIONS: Most radiologists and radiology trainees were in favor of completing the PGY-1 Basic Clinical Year. However, programs should maximize the education value of this year by including more of the top-ranked rotations. As the practice of radiology evolves, it is important to ensure that training paradigms continue to prepare residents for independent practice.

Radiology of soft tissue tumors.

Magnetic resonance imaging is the mainstay of diagnostic imaging for soft tissue masses, but plain film, ultrasound, and computed tomography all have roles. A subset of lesions has specific imaging features that enable a confident radiological diagnosis with appropriate clinical correlation. Many soft tissue masses have nonspecific appearances and should be considered for biopsy in a specialist center. When a biopsy is required for definitive diagnosis, careful multidisciplinary planning is essential to avoid contamination of unaffected tissue, leading to recurrence and unnecessary amputations. This article discusses radiological diagnosis, biopsy, and management of the soft tissue mass.

A practical guide to magnetic resonance vascular imaging: techniques and applications.

Magnetic resonance angiography is a technique used to image both central and peripheral arteries using contrast and noncontrast techniques. These techniques are similar in that a bright signal, which appears white within blood vessels, is generated and the background tissues, veins, and stationary tissues are dark. This allows for assessment of anatomy and vascular disease. Extracellular gadolinium-based contrast agents allow for excellent visualization of both central and peripheral arteries. Acquiring images during first pass is required for high-contrast images within arteries, thereby limiting contamination with contrast enhancement of veins and soft tissue. Contrast-enhanced techniques using time-resolved angiography and blood pool contrast agents minimize this temporal limitation. Noncontrast techniques eliminate the uncommon but potentially fatal complications associated with gadolinium contrast agents, such as nephrogenic systemic fibrosis. These techniques including phase contrast and time-of-flight sequences have inferior contrast resolution compared with contrast-enhanced techniques and are susceptible to artifacts, which can limit interpretation. The advantage, however, is the ability to assess vascular disease in patients with severe renal failure without the added risks of gadolinium contrast media. The aim of this review is to outline the different techniques available for imaging both the arterial and venous systems, their advantages and disadvantages, and the indications in vascular disease.

The John Charnley Award: Diagnostic accuracy of MRI versus ultrasound for detecting pseudotumors in asymptomatic metal-on-metal THA.

BACKGROUND: The prevalence of pseudotumors in patients with large-head metal-on-metal (MOM) THA has been the subject of implant recalls and warnings from various regulatory agencies. To date, there is no consensus on whether ultrasound or MRI is superior for the detection of pseudotumors. QUESTIONS/PURPOSES: We prospectively compared ultrasound to MRI for pseudotumor detection in an asymptomatic cohort of patients with MOM THAs. We also compared ultrasound to MRI for assessment of pseudotumor growth and progressive soft tissue involvement at a 6-month interval. METHODS: We enrolled 40 patients with large-head MOM THAs in the study. The mean age was 54 years (range, 34-76 years). The mean time from surgery was 54 months (range, 40-81 months). There were 28 men and 12 women. All patients underwent ultrasound and MRI using slice encoding for metal artifact correction. The gold standard was defined as follows: if both ultrasound and MRI agreed, this was interpreted as concordant and the result was considered accurate. RESULTS: Ultrasound and MRI agreed in 37 of 40 patients (93%). The prevalence of pseudotumors was 31% (12 of 39) in our cohort. Twenty-three of 39 patients (59%) had completely normal tests and four (10%) had simple fluid collections. Ultrasound had a sensitivity of 100% and specificity of 96% while MRI had a sensitivity of 92% and specificity of 100%. CONCLUSIONS: A negative ultrasound rules out pseudotumor in asymptomatic patients as this test is 100% sensitive. Given its lower cost, we recommend ultrasound as the initial screening tool for pseudotumors.

Weber osteotomy for large Hill-Sachs Defects: clinical and CT assessments.

BACKGROUND: The Weber derotation osteotomy is an uncommon procedure that typically is reserved for patients with engaging Hill-Sachs defects who have had other surgical treatments for shoulder instability fail. It is unknown whether the desired humeral derotation actually is achieved with the Weber osteotomy. QUESTIONS/PURPOSES: The purposes of this study were to answer the following questions: (1) What are the complication (including redislocation) and reoperation rates of the Weber osteotomy? (2) What are the American Shoulder and Elbow Surgeons (ASES) and functional (ROM in internal rotation, self care) results? (3) What fraction of the patients had humeral derotation within 10° of the desired rotation? METHODS: A chart review of 19 Weber osteotomies and clinical assessment of 10 Weber osteotomies were performed by independent clinicians. The chart review, at a mean followup of 51 months (range, 13-148 months), focused on the complication rate and the frequency of redislocation. The clinical and CT assessments, at a mean followup of 54 months (range, 26-151 months), focused on ASES scores, ability of patients to perform self care with the affected arm, and CT scans to measure change in humeral retroversion. RESULTS: There were 25 complications and nine reoperations in 17 patients (19 shoulders), including pain (six patients, of whom one had complex regional pain syndrome), hematoma, infection, nonunion, delayed union, reoperations related to hardware and other noninstability-related causes (five patients), and internal rotation deficit. Redislocation occurred in one patient, who underwent repeat surgery, and subjective instability developed in two others. The mean ASES score was 78 points (of 100 points); six of the 10 patients (11 procedures) evaluated in person found it difficult or were unable to wash their backs with the affected arm. Humeral derotation varied from 7° to 77°; only three of the nine patients for whom CT scans were available had derotation within 10° of the desired rotation. CONCLUSIONS: Complication rates with the Weber osteotomy were much higher than previously reported. Because seven of 17 patients were lost to followup, the redislocation rate may be higher than we observed here. Given the unpredictable variability in humeral derotation achieved with a Weber osteotomy, an improved surgical technique is critical to avoid osteoarthritis and loss of internal rotation associated with overrotation.

Clinics in diagnostic imaging (144). Lateral meniscal ossicle.

A 35-year-old female patient with previous left knee anterior cruciate ligament repair for a skiing injury presented six years later with a traumatic lateral patellar subluxation. Radiographs and magnetic resonance imaging of her left knee joint showed an ossific structure in the region of the lateral meniscus. This was diagnosed as a meniscal ossicle and confirmed during successful arthroscopic excision. The imaging features of meniscal ossicles are reported.

Evaluating bone marrow oedema patterns in musculoskeletal injury.

MRI is a common tool in the evaluation of musculoskeletal injury that allows the clinician to pinpoint specific pathologies. The patient's history and physical exam play a critical role in the diagnosis of sports injuries, however, complementary imaging can play an important role in determining the nature and extent of injury. With the widespread use of MRI, attention has focused on the signals generated following injury. In particular, bone marrow oedema (BME) patterns can be used to aid in the diagnosis of musculoskeletal injury. In this pictorial essay, the authors will demonstrate common patterns of BME that accompany a wide range of musculoskeletal injuries. It is expected that by the end of this article, the reader will be able to (1) recognise BME is a phenomenon observed on MRI following sports injury; (2) recognise typical patterns of BME; (3) understand the relationship of oedema to the type of injury and (4) in the presence of oedema, understand other co-existing injuries that ultimately may have an impact on management.

Get a kick out of this: the spectrum of knee extensor mechanism injuries.

At the end of this article, the reader should be able to (1) recognise normal anatomy and anatomical variants of the extensor mechanism of the knee on various imaging modalities, including plain film, ultrasound and MRI; (2) diagnose a broad spectrum of EM injuries in adult and paediatric patients including patellar and quadriceps tendinopathy, Osgood-Schlatter disease, Sindig-Larsen-Johansson syndrome, chondromalacia patellae and patellar fractures on various imaging modalities; and (3) appreciate the important role of imaging in the diagnosis of musculoskeletal injuries.

Can T2 relaxation values and color maps be used to detect chondral damage utilizing subchondral bone marrow edema as a marker?

OBJECTIVE: This study aimed to investigate whether a commercially available time-efficient T2 mapping sequence will demonstrate findings of articular cartilage degeneration based on T2 relaxation values (RV) and color maps, using subchondral bone marrow edema (BME) as a marker for chondral damage. MATERIALS AND METHODS: The patient group consisted of 88 subjects who underwent knee magnetic resonance imaging at 1.5 T who had subchondral BME evident on fat-suppressed T2-weighted sequences. The control group was comprised of 60 subjects with no evidence of subchondral BME. A commercially available eight echo T2 relaxation sequence (acquisition time 8:36 min) was used to construct a T2 color map and to determine T2 RVs. T2 RVs were determined on cartilage overlying subchondral BME in patients and in eight pre-determined anatomical regions in controls. T2 color maps in the patient and control groups were analyzed for degree of color stratification (presence = two or more colors) at the same anatomic site as that used for T2 RV determination. RESULTS: T2 RVs were significantly increased in patients compared to controls for the medial femoral condyle (MF; p < 0.01), medial patellar facet (MP; p < 0.01), lateral patellar facet (LP; p < 0.01), lateral femoral condyle (LF; p < 0.01) and lateral tibial plateau (LT; p < 0.01). Loss of color stratification was noted in patients compared to controls in the medial tibial plateau (MT; p = 0.01), LF (p < 0.01), and LT (p < 0.01). In the patient group, increase in T2 RVs was associated with corresponding decrease in color stratification in MF (p < 0.01), MT (p < 0.01), MP (p < 0.01), medial femoral trochlear groove (p = 0.02), and lateral femoral trochlear groove (p < 0.01). CONCLUSION: Subchondral BME was associated with an increase in adjacent articular cartilage T2 RVs at some sites. Also, elevated T2 RVs were associated with loss of color stratification.

Radiographic and computed tomographic studies of calcium hydroxylapatite for treatment of HIV-associated facial lipoatrophy and correction of nasolabial folds.

OBJECTIVES: This study sought to assess the radiographic appearance produced by calcium hydroxylapatite soft tissue filler (CaHA; Radiesse, BioForm Medical Inc.) following augmentation to correct the nasolabial folds or facial wasting associated with human immunodeficiency virus lipoatrophy. METHODS: A total of 58 patients, with either lipoatrophy or pronounced nasolabial folds, were treated with CaHA. Radiographic (X-ray) and computed tomographic (CT) imaging studies were conducted pre- and posttreatment in most patients; the images were sent to an independent laboratory to be analyzed by two evaluators who were board-certified radiologists and blinded to study purpose, product, and patient condition. RESULTS: While results for X-ray evaluation showed inconsistencies in visualization of CaHA, CT scans showed consistent visualization in nearly all cases in patients who were imaged immediately after treatment. In addition, the results indicated no obscuration of underlying structures by CaHA and no evidence of CaHA migration. CONCLUSIONS: Earlier clinical trials established CaHA as a safe and effective soft tissue filler. This CaHA study shows no overt radiographic safety concerns. CaHA is unlikely to be confused with conventional abnormal and adverse radiographic findings. The product is not always visible on X-ray. Although usually visible on CT scans, its appearance is distinct from surrounding bony structures and does not interfere with normal analysis. In addition, the product does not obscure underlying structures on CT scans.