ASSESSMENT OF PCXMC MONTE CARLO SIMULATIONS IN SLOT-SCANNING-BASED EXAMINATIONS: COMPARISON WITH IN-PHANTOM THERMOLUMINESCENT DOSIMETRY.

Slot-scanning technology is nowadays a valid solution for the follow-up of chronic musculoskeletal disorders on children and adolescent patients, but there is no commercial software designed for simulating this X-ray beam geometry. PC Program for X-ray Monte Carlo (PCXMC) is a widespread Monte Carlo software developed for dose computation in projection radiography. In this study, experimental measurements were performed to evaluate its applicability in examinations with a slit-beam device. Physical phantoms corresponding to an adult and a 5-y-old child with calibrated thermoluminescent dosemeters were used for experiments. Different simulation approaches were investigated. Differences between measured and calculated organ doses ranged from -95 to 67% and were statistically significant for almost all organs. For both patients, PCXMC underestimated the effective dose of about 25%. This study suggests that PCXMC is not suited for organ dose evaluation in examinations with slot-scanning devices. It is still a useful tool for effective dose estimation when a proper correction factor is applied.

Evaluation of mental foramen and inferior alveolar nerve canal and its relationship to adjacent anatomical landmarks using cone-beam computer tomography.

The objective of the research was to evaluate the location, size, variability, and morphologic features of mental foramen (MF) and the inferior alveolar nerve canal (IAN) on cone-beam CT. We evaluated the morphologic findings of mental foramen (MF) and inferior alveolar nerve (IAN) canal of 88 mandibular hemiarches of 65 Caucasian subjects (35 males, 30 females; age range 25-75 years) using cone beam CT. The most common horizontal position of MF was type 3 (53.4%), followed by type 4 (39.8%), type 1 (2.3%), type 2 (2.3%), and type 5 (2.3%). Regarding the vertical position, in 71.6% of cases (63/88) we found type 3 position, followed by type 2 (22.7%) and type 1 (5.7%). MF presented as oval in 51.1% and round in 42%, with double oval and triple foramens having been observed in 5.7% and 1.1% respectively. In 36.9% of cases, we found an anterior loop of the IAN. The mean depth of MF was 6.12±1.65mm; width and height were 3.7±0.83mm and 3.14±0.78mm. Width and height of the IAN distal to MF were 2.27±0.53mm and 2.74±0.51mm, while those of the incisive nerve canal mesial to MF were 1.37±0.44mm and 1.54±0.58mm, respectively. An increase in the width of MF was correlated to oval shape (r=0.45; P < 0.01), and there was a low but significant correlation (r=0.23; P < 0.05) between the round shape of MF and the size of the IAN. MF shape appears to be correlated to MF width and size of the IAN. The individual anatomical variability of this structure is a factor that must be considered when dealing with mandibular surgery.

Disruption of bone densitometry practice in a Northern Italy Orthopedic Hospital during the COVID-19 pandemic.

We report the impact of the COVID-19 pandemic on bone densitometry practice in a Northern Italy Orthopedic Hospital, comparing the first 4 months of 2020 with the corresponding period of 2019. COVID-19 pandemic had a disruptive effect on the daily practice of bone densitometry (about - 50% of examinations). INTRODUCTION: The Coronavirus Disease 2019 (COVID-19) pandemic radically changes hospital organization to guarantee patient and staff safety, with the unavoidable cessation of normal outpatient activities. We report the impact of the COVID-19 pandemic on dual energy x-ray absorptiometry (DXA) testing in a Northern Italy Orthopedic Hospital. METHODS: We analyzed the number of DXA examinations performed at our Institution before, during the lockdown, and immediately after outpatient practice reopening (January 24th to May 27th, 2020), comparing them with the corresponding period of 2019. RESULTS: The number of DXA examinations showed a tremendous reduction from n = 1247 performed from January to May 2019 to n = 623 of 2020 (- 49.9%). No exams were performed in April 2020 (- 100%). On May 2020, a faint resume was observed, with n = 43 DXA (- 84.4% compared to 2019). CONCLUSION: COVID-19 pandemic had a disruptive effect on the daily practice of bone densitometry with DXA. After reopening, we observed a persistence of DXA examination reduction, confirming the fact that returning to normality will probably be a slow process.

Prediction of osteoporotic fragility re-fracture with lumbar spine DXA-based derived bone strain index: a multicenter validation study.

A new qualitative index of bone strength, based on finite element analysis and named bone strain index, has been recently developed from lumbar DXA scan. This study shows that BSI predicts subsequent re-fracture in osteoporotic patients affected by fragility fractures. INTRODUCTION: Dual-energy X-ray absorptiometry (DXA) can provide quantitative (bone mineral density, BMD) and qualitative (trabecular bone score, TBS) indexes of bone status, able to predict fragility fractures in most osteoporotic patients. A new qualitative index of bone strength, based on finite element analysis and named bone strain index (BSI), has been recently developed from lumbar DXA scan. This study presents the validation results of BSI prediction for re-fracture in osteoporotic patients with fragility fractures. METHODS: In three academic hospitals, 234 consecutive fractured patients with primary osteoporosis (209 females) performed a spine X-ray for the calculation of spine deformity index (SDI) and DXA densitometry for BMD, TBS and BSI at the basal time and in the follow-up at each clinical check. A subsequent fracture was considered as one unity increase of SDI. RESULTS: For each unit increase of the investigated indexes, the univariate hazard ratio of re-fracture, 95% CI, p value and proportionality test p value are for age 1.040, 1.017-1.064, 0.0007 and 0.2529, respectively, and for BSI 1.372, 1.038-1.813, 0.0261 and 0.5179, respectively. BSI remained in the final multivariate model as a statistically significant independent predictor of a subsequent re-fracture (1.332, 1.013-1.752 and 0.0399) together with age (1.039, 1.016-1.064 and 0.0009); for this multivariate model proportionality test, p value is 0.4604. CONCLUSIONS: BSI appears to be a valid DXA index of prediction of re-fracture, and it can be used for a more refined risk assessment of osteoporotic patients.

Are clinical practice guidelines for low back pain interventions of high quality and updated? A systematic review using the AGREE II instrument.

BACKGROUND: Clinical practice guidelines (CPGs) provide recommendations for practice, but the proliferation of CPGs issued by multiple organisations in recent years has raised concern about their quality. The aim of this study was to systematically appraise CPGs quality for low back pain (LBP) interventions and to explore inter-rater reliability (IRR) between quality appraisers. The time between systematic review search and publication of CPGs was recorded. METHODS: Electronic databases (PubMed, Embase, PEDro, TRIP), guideline organisation databases, websites, and grey literature were searched from January 2016 to January 2020 to identify GPCs on rehabilitative, pharmacological or surgical intervention for LBP management. Four independent reviewers used the Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool to evaluate CPGs quality and record the year the CPGs were published and the year the search strategies were conducted. RESULTS: A total of 21 CPGs met the inclusion criteria and were appraised. Seven (33%) were broad in scope and involved surgery, rehabilitation or pharmacological intervention. The score for each AGREE II item was: Editorial Independence (median 67%, interquartile range [IQR] 31-84%), Scope and Purpose (median 64%, IQR 22-83%), Rigour of Development (median 50%, IQR 21-72%), Clarity and Presentation (median 50%, IQR 28-79%), Stakeholder Involvement (median 36%, IQR 10-74%), and Applicability (median 11%, IQR 0-46%). The IRR between the assessors was nearly perfect (interclass correlation 0.90; 95% confidence interval 0.88-0.91). The median time span was 2 years (range, 1-4), however, 38% of the CPGs did not report the coverage dates for systematic searches. CONCLUSIONS: We found methodological limitations that affect CPGs quality. In our opinion, a universal database is needed in which guidelines can be registered and recommendations dynamically developed through a living systematic reviews approach to ensure that guidelines are based on updated evidence. LEVEL OF EVIDENCE: 1 TRIAL REGISTRATION: REGISTRATION PROSPERO DETAILS: CRD42019127619 .

Fragility fractures and bone mineral density in male patients affected by type 1 and type 2 myotonic dystrophy.

Myotonic dystrophy is a multisystemic disorder affecting skeletal muscle. Male patients have an increased risk of fractures and develop a number of endocrine/metabolic impairments known to adversely affect bone health. The aim of this study was primarily to determine the occurrence of fragility fractures and the bone mineralization status (lumbar spine, hip and total body by dual X-ray absorptiometry) in 36 male patients affected with type 1 myotonic dystrophy and 13 male patients affected with type 2 myotonic dystrophy. Fragility fractures occurred in 15 type 1 and 7 type 2 myotonic dystrophy in non-classical osteoporotic sites, such as metatarses. Hip osteopenia was the most frequent finding, particularly in type 2 (n = 6) than type 1 myotonic dystrophy patients (n = 1), while osteoporosis was rare. Patients with type 1 myotonic dystrophy presented higher total body bone mass density than patients with type 2 myotonic dystrophy and healthy controls and lumbar spine was associated positively with the severity of the disease. Gonadic failure, with low testosterone and reduced INSL3 levels, visceral adiposity and insulin resistance correlated with reduced body mass index in both type 1 and type 2 myotonic dystrophic patients. The independent determinant of fragility fractures were low total body mass index, low blood testosterone and low global muscle mass.

Bone strain index reproducibility and soft tissue thickness influence: a dual x-ray photon absorptiometry phantom study.

BACKGROUND: Bone strain index (BSI) is a tool measuring bone strain, derived from dual x-ray photon absorptiometry. It is able to characterise an aspect of bone quality that, joined to the quantity and quality parameters of bone mineral density (BMD) and trabecular bone score (TBS), permits an accurate definition of fracture risk. As no data are available about BSI precision, our aim was to assess its in vitro reproducibility. METHODS: A Hologic spine phantom was used to perform BSI scans with three different scan modes: fast array (FA), array (A), and high definition (HD). Different soft tissue thicknesses (1, 3, 6 cm) of fresh pork rind layers as a surrogate of abdominal fat were interposed. For each scan mode, the phantom was consecutively scanned 25 times without repositioning. RESULTS: In all scan modes (FA, A, HD) and at every fat thickness, BSI reproducibility was lower than that of BMD. The highest reproducibility was found using HD-mode with 1 cm of pork rind and the lowest one using HD-mode with 6 cm of pork rind. Increasing fat thickness, BSI reproducibility tended to decrease. BSI least significant change appeared to be about three times that of BMD in all modalities and fat thicknesses. Without pork rind superimposition and with 1-cm fat layer, BSI reproducibility was highest with HD-mode; with 3 or 6 cm fat thickness, it was higher with A-mode. CONCLUSIONS: BSI reproducibility was worse than that of BMD, but it is less sensitive to fat thickness increase, similarly to TBS.

Accuracy of CT and MRI to assess resection margins in primary malignant bone tumours having histology as the reference standard.

AIM: To evaluate the accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) in assessing the resection margins of primary malignant bone tumours. MATERIALS AND METHODS: Resected primary malignant bone tumour specimens removed from 46 patients (27 male; mean age: 48±22 years) were imaged using MRI (fat-saturated proton density-weighted and three-dimensional fat-suppressed T1-weighted gradient-recalled-echo) and CT immediately after surgery. A radiologist and an orthopaedist evaluated bone and soft-tissue margins of the specimens on both examinations. Histological evaluation was performed by a senior orthopaedic oncology pathologist. Margins were classified as R0 (safe margins), R1 (residuals between 0 and 1 mm), and R2 (macroscopic residuals). Cohen's k, chi-square, and McNemar's statistics were used. RESULTS: Having histology as the reference standard, reproducibility of the radiologist ranged from moderate (k=0.544) to substantial (k=0.741) for bone and soft-tissue margins on CT, respectively, while that of the orthopaedist ranged from fair (k=0.316) to moderate (k=0.548). When comparing R2 and R0+R1 scores, reproducibility of readers' evaluation of bone margins increased ranging from substantial (k=0.655) to perfect (k=1.000). Inter-reader agreement ranged from fair (k=0.308) to substantial (k=0.633). Accuracy of the radiologist and orthopaedist ranged from 76% to 83% and from 68% to 72%, respectively. When comparing R2 and R0+R1 scores, the accuracy of both readers ranged from 83% to 100%. There was no association between local recurrence and margin scores of histology, MRI, and CT (p≥0.058). CONCLUSIONS: MRI and CT may be useful for extemporaneous analysis of resection margins of primary malignant bone tumours, although wide accuracy variability between the different imaging methods was observed.

Skeletal idiopathic osteosclerosis helps to perform personal identification of unknown decedents: A novel contribution from anatomical variants through CT scan.

Personal identification consists of the comparison of ante-mortem information from a missing person with post-mortem data obtained from an unidentified corpse. Such procedure is based on the assessment of individualizing features which may help in providing a conclusive identification between ante-mortem and post-mortem material. Anatomical variants may provide important clues to correctly identify human remains. Areas of idiopathic osteosclerosis (IO), or dense bone islands (DBIs) characterized by radiopaque areas of dense, trabeculated, non-inflamed vital bone represent one of these, potentially individualizing, anatomical features. This study presents a case where the finding of DBI was crucial for a positive identification through CT-scan. A decomposed body was found in an apartment in June 2014 in advanced decomposition and no dental records were available to perform a comparison for positive identification. Genetic tests were not applicable because of the lack of relatives in a direct line. The analysis of the only ante-mortem documentation, a CT-scan to the deceased dating back to August 2009, showed the presence of three DBIs within the trabecular bone of the proximal portion of the right femur. The same bony district was removed from the corpse during the autopsy and analysed by CT-scan, which verified the presence of the same features. Forensic practitioners should therefore be aware of the great importance of anatomical bone variants, such as dense bone islands for identification purposes, and the importance of advanced radiological technique for addressing the individualizing potential of such variants. We propose that anatomical variants of the human skeleton should be considered as being "primary identification characteristics" similar to dental status, fingerprints and DNA.

Ultrasound in the diagnosis of calcium pyrophosphate dihydrate deposition disease. A systematic literature review and a meta-analysis.

OBJECTIVE: Ultrasonography (US) demonstrated to be a promising tool for the diagnosis of calcium pyrophosphate dihydrate deposition disease (CPPD). The aim of this systematic literature review (SLR) was to collect the definitions for the US elementary lesions and to summarize the available data about US diagnostic accuracy in CPPD. METHODS: We systematically reviewed all the studies that considered US as the index test for CPPD diagnosis without restrictions about the reference test or that provided definitions about US identification of CPPD. Sensitivity and specificity were calculated for each study and definitions were extrapolated. Subgroup analyses were planned by anatomical site included in the index text and different reference standards. RESULTS: Thirty-seven studies were included in this review. All the studies were eligible for the collection of US findings and all definitions were summarized. US description of elementary lesions appeared heterogeneous among the studies. Regarding US accuracy, 13 articles entered in the meta-analysis. Considering each joint structure, the sensitivity ranged between 0.77 (0.63-0.87) and 0.34 (0.16-0.58) while the specificity varies between 1.00 (0.89-1.00) and 0.92 (0.16-1.00). Considering the reference standards used, the sensibility ranged between 0.34 (0.02-0.65) and 0.87 (0.76-0.99) while specificity ranged between 0.84 (0.52-1.00) and 1.00 (0.99-1.00). CONCLUSION: US is potentially a useful tool for the diagnosis of CPPD but universally accepted definitions and further testing are necessary in order to assess the role of the technique in the diagnostic process.

Radiologists and rheumatologists on performing and reporting shoulder ultrasound: from disagreement to consensus.

Shoulder pain is a common condition in the rheumatologist's practice, yet there are no guidelines on how to report shoulder ultrasound (US) examinations. The aim of this study was to compare scanning and reporting techniques performed by radiologists and rheumatologists and identify any discrepancies between the two. The participants in this study were five rheumatologists and two radiologists specialized in musculoskeletal US. The study was divided in 2 phases. In the first phase, each participant performed an US of 3 patients and reported the findings without knowing the patient diagnosis and the findings reported by the other operators. Other three investigators reported the US technique of each operator. Reports and images were subsequently compared to identify any discrepancies and reach consensus on a common approach. In the second phase, a US scan was performed on a fourth patient in a plenary session to assess feasibility and efficacy of the common approach The US scanning technique was similar for all operators. The differences in reporting emerged in the description of the rotator cuff disease. Radiologists provided a detailed description of lesions (measurements along 2 axis and scoring of lesions), whereas rheumatologists described carefully the inflammatory changes. The experts concluded that lesions should be measured along 2 axes and the grade of degeneration and the age of the lesion should be reported. Another difference emerged in the description of the irregularities of the bone surface. The experts concluded that the term erosion should be used only when an inflammatory joint disease is suspected. This study led to the clarification of some inconsistencies in US reporting, and represented an interesting collaborative experience between radiologists and rheumatologists.

Diagnostic flowcharts in osteomyelitis, spondylodiscitis and prosthetic joint infection.

Infections of the bone, spine and prosthetic joints are serious and complex conditions to diagnose and to treat. Structured diagnostic workup may very well improve the accuracy and speed of diagnosis, thereby improving the outcome since treatment may very well be more successful and less harmful if timely management is started. Literature shows no uniform advise on diagnosis. The EANM organized a consensus meeting with representatives from the involved disciplines in order to develop common flowcharts for the diagnosis of osteomyelitis, spondylodiscitis and prosthetic joint infections. In this report the proceedings of this consensus meeting, including the proposed flowcharts for diagnosis, are published.

Diagnosing diabetic foot infection: the role of imaging and a proposed flow chart for assessment.

Diabetes mellitus, a major current epidemic, is frequently complicated by foot infections that are associated with high morbidity. Diagnosing these infections, especially whether or not underlying bone is involved, poses clinical challenges, but is crucial to making proper decisions regarding therapeutic strategies. The most effective means of managing patients with a diabetic foot infection is within the framework of a multidisciplinary team. Present diagnostic efforts are aimed at developing better methods to differentiate uninfected from infected soft tissue wounds, to determine when bone infection is present, and to more clearly define when infection has resolved with treatment. Imaging studies play a major role in diagnosis. This usually begins with plain radiographs, but when advanced imaging is needed, magnetic resonance imaging (MRI) is considered the modality of choice. Newer techniques, such as molecular hybrid imaging, positron emission tomography (PET)/computed tomography (CT) and single photon emission (SPECT)/CT using various radiotracers, play an increasing role. These tests may redefine the non-invasive diagnostic work-up of diabetic foot wounds, potentially leading to substantial improvements in patient management. As experts in infectious diseases, radiology and nuclear medicine, we reviewed the available literature on diagnosing diabetic foot infections, especially the currently available imaging techniques, and developed a proposed diagnostic flow chart, for evaluating patients with a diabetic foot wound.

The use of CEUS in the diagnosis of retinal/choroidal detachment and associated intraocular masses - preliminary investigation in patients with equivocal findings at conventional ultrasound.

PURPOSE: To investigate whether contrast-enhanced ultrasound (CEUS) may help to diagnose retinal/choroidal detachment and may help to differentiate intraocular lumps in cases with equivocal features on conventional grayscale and Doppler modes. MATERIALS AND METHODS: The institutional review board approved this retrospective study. The need for informed consent was waived. A computerized data search was performed in the database of our institution for patients with vitreous hemorrhage who underwent CEUS of the eye to assess retinal/choroidal detachment and/or associated masses. This process yielded a total of 31 patients (18 men, 13 women, age range: 39 - 88 years) in whom CEUS was performed because the findings on conventional grayscale and Doppler modes were equivocal. CEUS was performed using low acoustic power contrast-specific modes. A 2.4 - 4.8  mL bolus of SonoVue was injected, followed by a saline flush. All examinations were digitally recorded for retrospective analysis. Confirmation of CEUS findings was obtained at surgery (n = 20) or with binocular indirect fundoscopy performed after clearance of the ocular media (n = 11). Two readers with different levels of ultrasound experience independently reviewed the imaging features. A five-degree scale ranging from definitely absent (score 1) to definitely present (score 5) was used to assess the presence or absence of retinal/choroidal detachment on conventional ultrasound modes alone and with the addition of CEUS. ROC curve analysis was performed to assess the diagnostic accuracy of both methods. The inter-reader agreement was also evaluated. In patients with associated intraocular lumps, conventional Doppler modes and CEUS were used to differentiate non-tumor masses from tumor masses. RESULTS: According to the reference standard, 13 patients had retinal detachment, 4 had choroidal detachment, and 3 had both retinal and choroidal detachment. There were 8 associated intraocular lumps (4 subretinal hemorrhages, 3 malignant melanomas, 1 metastasis). The inter-reader agreement was good (K = 0.644) and very good (K = 0.833) for conventional modes and CEUS, respectively. The diagnostic performance of CEUS was high for both readers (area ± standard error under the ROC curve: 0.966 ±â€Š0.031 and 0.900 ±â€Š0.055 for readers 1 and 2, respectively). There were 2 false-positive results and 1 false-negative result in patients with proliferative diabetic retinopathy. CEUS was effective in differentiating subretinal hemorrhage from hypovascular tumors. CONCLUSION: CEUS can be used as a problem-solving technique when conventional ultrasound modes are not diagnostic for retinal/choroidal detachment and when intraocular lumps cannot be characterized as tumor or non-tumor masses on conventional modes. The evaluation of patients with proliferative diabetic retinopathy, however, may be problematic.

Bone mineral density differences between femurs of scoliotic patients undergoing dual-energy X-ray absorptiometry.

AIM: To investigate whether a difference exists in the bone mineral density (BMD) between femurs in scoliotic patients undergoing dual-energy X-ray absorptiometry (DXA) and whether this difference is related to spine convexity. MATERIALS AND METHODS: Of 1080 consecutive patients who underwent DXA, 127 had lumbar scoliosis seen at DXA. Further, after excluding 30 patients with previous osteoporotic fractures, metallic/image artefacts, soft-tissue calcifications, the BMD differences between femurs of 97 scoliotic patients (94 females; mean age 67 ± 11 years) were analysed. Femurs were classified as ipsilateral or contralateral to the spine convexity. Least significant change was used as a threshold of measurement precision. Differences between femoral neck BMD in respect of and regardless of spine convexity were calculated for each patient. Student's t-test and Wilcoxon's signed-rank test were used to assess significance. RESULTS: Fifty-nine of 97 patients (61%) had left-sided scoliosis. Osteoporosis was found in 32/97 patients (33%), osteopenia in 54/97 (56%), and 11/97 (11%) had a normal T-score. Of 97 patients, 46 (47%) had ipsilateral BMD < contralateral BMD. Regardless of spine convexity, 66/97 patients (68%) had different BMD values between femurs. Among them, variation of densitometric diagnosis was seen in 29/66 patients (44%), and in 29/97 patients overall (30%). CONCLUSION: Differences in the femoral neck BMD exist between femurs of scoliotic patients undergoing DXA. Thus, bilateral femoral DXA acquisition is recommended.

Preliminary ultrasound evaluation of the rotator cable in asymptomatic volunteers().

PURPOSE: To characterize the rotator cable high-resolution ultrasound appearance in asymptomatic shoulders of volunteers of different age. MATERIALS AND METHODS: IRB approval and volunteers' written consent was obtained. Excluding subjects with known shoulder affections, we screened 24 asymptomatic volunteers. Supraspinatus and infraspinatus tendons high-resolution ultrasound evaluation was performed according to standard scan protocols, further excluding shoulders with partial/full-thickness cuff tears. Thus, we studied 24 shoulders in 12 young volunteers (age range 21-39 years, mean age 33 ± 8 years) and 21 shoulders in 11 elderly volunteers (age range 62-83 years, mean age 75 ± 45 years). For each shoulder, we noted rotator cable visibility and its thickness and width. Fisher's and U Mann-Whitney statistics were used. RESULTS: Rotator cable was less frequently detected in young than in elderly volunteers (5/24 vs. 11/21 shoulders; P = 0.034). When detected, rotator cable was significantly thicker in young (range 1.2-1.5 mm, mean thickness 1.3 ± 0.1 mm) than in elderly (range 0.9-1.4 mm, mean thickness 1.2 ± 0.1 mm) volunteers (P = 0.025), while its width was not significantly different in young (range 4.5-7.1 mm, mean 5.6 ± 1.1 mm) compared to elderly (range 2.5-7.1 mm, mean 4.2 ± 1.4 mm) volunteers (P = 0.074) although a tendency can be highlighted. CONCLUSIONS: Ultrasound demonstrated the different consistency of rotator cable in young and elderly asymptomatic patients, with high interobserver reproducibility.

Magnetic resonance imaging of painful total hip replacement: detection and characterisation of periprosthetic fluid collection and interobserver reproducibility.

PURPOSE: The purpose of our study was to demonstrate the diagnostic value of magnetic resonance imaging (MRI) when measuring and characterising periprosthetic fluid collections in patients with painful hip prosthesis and to provide an estimation of interobserver reproducibility. MATERIALS AND METHODS: Nineteen patients (mean age 59±13 years) with painful total hip replacement and clinical suspicion of infection underwent MRI. Images were reviewed blindly by two musculoskeletal radiologists with different levels of experience who evaluated the presence/absence of soft tissue oedema or fluid collection (when present, three-plane maximal diameters were measured; involvement of skin/subcutaneous/deep tissues or prosthesis were estimated; fluid was classified as serous/purulent/haematic according to signal behaviour). Interobserver agreement was calculated (Cohen's ). RESULTS: A total of 26 MRI studies were carried out (three patients underwent two and two patients underwent three MRI examinations). Both readers detected soft tissue oedema (13/26, 50%) or fluid collection (21/26, 81%) and characterised the fluid as serous (9/21, 43%), purulent (8/21, 38%) or haematic (4/21, 19%). The collection involved skin/subcutaneous tissues (16/21, 76%), deep soft tissues (19/21, 91%) or the implant (12/21, 57%). For all evaluations, interobserver agreement was complete (=1). No significant differences were found between the measurements of the collections (p>0.258). CONCLUSIONS: MRI is highly reproducible in detection, localisation, quantification, and characterisation of fluid collections when the presence of implant infection is clinically suspected.

High-resolution ultrasound of the extrinsic carpal ligaments.

Thanks to its intrinsic high spatial resolution, ultrasound is an ideal imaging modality for examining very thin, superficial structures, and this makes it very helpful in the evaluation of extrinsic carpal ligaments. These structures, which arise from the radius and ulna and insert on the carpal bones, are extremely important for wrist stability. Previous studies have assessed the use of ultrasound to study the extrinsic carpal ligaments in cadavers, healthy asymptomatic subjects, and patients with rheumatoid arthritis. In the present report, we review the normal anatomy, biomechanics, and ultrasound appearance of these ligaments.