Large variation in radiation dose for routine abdomen CT: reasons for excess and easy tips for reduction.

OBJECTIVE: To characterize the use and impact of radiation dose reduction techniques in actual practice for routine abdomen CT. METHODS: We retrospectively analyzed consecutive routine abdomen CT scans in adults from a large dose registry, contributed by 95 hospitals and imaging facilities. Grouping exams into deciles by, first, patient size, and second, size-adjusted dose length product (DLP), we summarized dose and technical parameters and estimated which parameters contributed most to between-protocols dose variation. Lastly, we modeled the total population dose if all protocols with mean size-adjusted DLP above 433 or 645 mGy-cm were reduced to these thresholds. RESULTS: A total of 748,846 CTs were performed using 1033 unique protocols. When sorted by patient size, patients with larger abdominal diameters had increased dose and effective mAs (milliampere seconds), even after adjusting for patient size. When sorted by size-adjusted dose, patients in the highest versus the lowest decile in size-adjusted DLP received 6.4 times the average dose (1680 vs 265 mGy-cm) even though diameter was no different (312 vs 309 mm). Effective mAs was 2.1-fold higher, unadjusted CTDIvol 2.9-fold, and phase 2.5-fold for patients in the highest versus lowest size-adjusted DLP decile. There was virtually no change in kV (kilovolt). Automatic exposure control was widely used to modulate mAs, whereas kV modulation was rare. Phase was the strongest driver of between-protocols variation. Broad adoption of optimized protocols could result in total population dose reductions of 18.6-40%. CONCLUSION: There are large variations in radiation doses for routine abdomen CT unrelated to patient size. Modification of kV and single-phase scanning could result in substantial dose reduction. CLINICAL RELEVANCE: Radiation dose-optimization techniques for routine abdomen CT are routinely under-utilized leading to higher doses than needed. Greater modification of technical parameters and number of phases could result in substantial reduction in radiation exposure to patients. KEY POINTS: • Based on an analysis of 748,846 routine abdomen CT scans in adults, radiation doses varied tremendously across patients of the same size and optimization techniques were routinely under-utilized. • The difference in observed dose was due to variation in technical parameters and phase count. Automatic exposure control was commonly used to modify effective mAs, whereas kV was rarely adjusted for patient size. Routine abdomen CT should be performed using a single phase, yet multi-phase was common. • kV modulation by patient size and restriction to a single phase for routine abdomen indications could result in substantial reduction in radiation doses using well-established dose optimization approaches.

Diagnostic reference levels and median doses for common clinical indications of CT: findings from an international registry.

OB JECTIVES: The European Society of Radiology identified 10 common indications for computed tomography (CT) as part of the European Study on Clinical Diagnostic Reference Levels (DRLs, EUCLID), to help standardize radiation doses. The objective of this study is to generate DRLs and median doses for these indications using data from the UCSF CT International Dose Registry. METHODS: Standardized data on 3.7 million CTs in adults were collected between 2016 and 2019 from 161 institutions across seven countries (United States of America (US), Switzerland, Netherlands, Germany, UK, Israel, Japan). DRLs (75th percentile) and median doses for volumetric CT-dose index (CTDIvol) and dose-length product (DLP) were assessed for each EUCLID category (chronic sinusitis, stroke, cervical spine trauma, coronary calcium scoring, lung cancer, pulmonary embolism, coronary CT angiography, hepatocellular carcinoma (HCC), colic/abdominal pain, appendicitis), and US radiation doses were compared with European. RESULTS: The number of CT scans within EUCLID categories ranged from 8,933 (HCC) to over 1.2 million (stroke). There was greater variation in dose between categories than within categories (p < .001), and doses were significantly different between categories within anatomic areas. DRLs and median doses were assessed for all categories. DRLs were higher in the US for 9 of the 10 indications (except chronic sinusitis) than in Europe but with a significantly higher sample size in the US. CONCLUSIONS: DRLs for CTDIvol and DLP for EUCLID clinical indications from diverse organizations were established and can contribute to dose optimization. These values were usually significantly higher in the US than in Europe. KEY POINTS: • Registry data were used to create benchmarks for 10 common indications for CT identified by the European Society of Radiology. • Observed US radiation doses were higher than European for 9 of 10 indications (except chronic sinusitis). • The presented diagnostic reference levels and median doses highlight potentially unnecessary variation in radiation dose.

Radiologists' Increasing Role in Population Health Management: AJR Expert Panel Narrative Review.

Population health management (PHM) is the holistic process of improving health outcomes of groups of individuals through the support of appropriate financial and care models. Radiologists' presence at the intersection of many aspects of health care, including screening, diagnostic imaging, and image-guided therapies, provides the opportunity for increased radiologist engagement in PHM. Furthermore, innovations in artificial intelligence and imaging informatics will serve as critical tools to improve value in health care through evidence-based and equitable approaches. Given radiologists' limited engagement in PHM to date, it is imperative to define the PHM priorities of the specialty so that radiologists' full value in improving population health is realized. The purpose of this expert review is to explore programs and future directions for radiologists in PHM.

The Use of Contrast Agents in Interventional Pain Procedures: A Multispecialty and Multisociety Practice Advisory on Nephrogenic Systemic Fibrosis, Gadolinium Deposition in the Brain, Encephalopathy After Unintentional Intrathecal Gadolinium Injection, and Hypersensitivity Reactions.

This Practice Advisory presents a comprehensive and evidence-based set of position statements and recommendations for the use of contrast media in interventional pain procedures. The advisory was established by an international panel of experts under the auspices of 11 multinational and multispecialty organizations based on a comprehensive review of the literature up to December 31, 2019. The advisory discusses the risks of using gadolinium-based contrast agents. These include nephrogenic systemic fibrosis, gadolinium brain deposition/retention, and encephalopathy and death after an unintentional intrathecal gadolinium injection. The advisory provides recommendations on the selection of a specific gadolinium-based contrast agent in patients with renal insufficiency, those who had multiple gadolinium-enhanced magnetic resonance imaging examinations, and in cases of paraspinal injections. Additionally, recommendations are made for patients who have a history of mild, moderate, or severe hypersensitivity reactions to contrast medium.

Accuracy of ultrasound in the characterisation of deep soft tissue masses: a prospective study.

PURPOSE: To investigate the accuracy of ultrasound in characterising the type of mass and likelihood of malignancy in deep soft tissue masses. METHODS: Five hundred seventy-nine deep soft tissue masses were prospectively studied by ultrasound. Masses (n = 137) with prior MRI or CT were not included. Following ultrasound examination, the likely nature of the mass as well as the confidence of the reporting radiologist ('fully confident' versus 'not fully confident') about the ultrasound diagnosis was recorded. Clinical and ultrasound diagnoses were compared with the histological diagnosis which was available in 134 (23%) of the 579 masses. RESULTS: Compared with histology, clinical and ultrasound accuracy for characterising the type of mass were 47% and 88% respectively when all differential diagnoses were considered. The radiologist was fully confident regarding the type of 436 (75%) of 579 masses and, in this setting, for those cases that could be compared with histology, diagnostic accuracy was 96%. For the remaining masses, where the radiologist was not fully confident, accuracy compared with histology was 58% for the first differential diagnosis and 80% for all differential diagnoses. For identifying malignancy, sensitivity, specificity, and positive and negative predictive value of ultrasound were 97%, 58%, 67%, and 99% respectively. Ultrasound alone was considered sufficient for diagnostic workup in over half of all deep soft tissue masses. CONCLUSION: Ultrasound is useful at characterising and recognising malignancy in deep soft tissue masses. Provided local practice patterns are favourable, ultrasound may be considered a first-line investigation in the diagnostic workup of deep soft tissue masses. KEY POINTS: • In three-quarters of cases, one can be fully confident about characterising the nature of deep soft tissue masses on ultrasound and, for those fully confident cases that could be compared with histology, the diagnostic accuracy of ultrasound was 96%. • Ultrasound can correctly recognise nearly all malignant deep soft tissue masses but some benign masses will also be considered possibly malignant. • Ultrasound alone was considered sufficient for imaging workup in over half of deep soft tissue masses.

ERAMRS: a new MR scoring system for early rheumatoid arthritis of the wrist.

PURPOSE: To (i) devise a new semi-quantitative scoring system known as Early Rheumatoid Arthritis Magnetic Resonance Score (ERAMRS) to assess inflammation of the wrist on magnetic resonance imaging in early rheumatoid arthritis and to (ii) test ERAMRS and other MR scoring systems against everyday used clinical scorings. MATERIALS AND METHODS: One hundred six treatment-naïve patients (81 females, 25 males, mean age 53 ± 12 years) with early rheumatoid arthritis (ERA) underwent clinical/serological testing as well as 3-T MRI examination of the most symptomatic wrist. Clinical assessment included Disease Activity Score-28 and Health Assessment Questionnaire; erythrocyte sedimentation rate and C-reactive protein were measured. MR imaging data was scored in all patients using three devised MR semi-quantitative scoring systems, namely, the (a) ERAMRS system, (b) Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS) system, and the (c) McQueen Score system. RESULTS: Synovitis was present in 106 (100%), tenosynovitis in 98 (92%), and bone marrow edema in 84 (79%) of 106 ERA wrists. ERAMRS had the highest correlation with clinical disease activity scores (r = 0.476, p < 0.001) and serological parameters (r = 0.562, p < 0.001). RAMRIS system had the lowest correlation (r = 0.369, p < 0.001 for clinical disease activity; r = 0.436, p < 0.001 for serological parameters). RAMRIS synovitis subscore had a lower correlation than ERAMRS for clinical disease activity (r = 0.410, p < 0.001) and for serological parameters (r = 0.456, p < 0.001). CONCLUSION: The ERAMRS system, designed to grade inflammation on wrist MRI in ERA, provided the best correlation with all clinical scoring systems and serological parameters, indicating its improved clinical relevance over other MR scoring systems. KEY POINTS: • We devised a clinically relevant, easy-to-use semi-quantitative scoring system for scoring inflammation on MRI of the wrist in patients with early rheumatoid arthritis. • ERAMRS system showed better correlation with all clinical and serological assessment of inflammation in patients with early rheumatoid arthritis indicating its improved clinical relevance over other MR scoring systems.

Cross-sectional area of the median nerve at the wrist: Comparison of sonographic, MRI, and cadaveric measurements.

BACKGROUND: This study compares median nerve cross-sectional area (CSA) measurements at the wrist obtained with ultrasound (US) and magnetic resonance imaging (MRI) using cadaveric measurements as the gold standard. METHODS: Median nerve CSA was measured using US and MRI in 9 cadaveric wrists obtained from 5 subjects at 5 locations: distal forearm, proximal to tunnel inlet, at tunnel inlet, at tunnel outlet, and distal to tunnel outlet and then on identical cadaveric transverse sections obtained with a bandsaw. All US, MRI, and cadaveric measurements were repeated to determine reliability. Median nerves of 10 patients with clinical carpal tunnel syndrome (CTS) were measured with US and MRI using an identical method US. RESULTS: Median nerve CSA MRI measurements correlated better (Pearson correlation: 0.80-0.95, P < .05) with cadaveric measurements than with US measurements (Pearson correlation: 0.61-0.79, P < .05). Median nerve CSA US measurements (8.6-12.5 mm2 , P < .05) were smaller at all levels than MRI (11.3-14.7 mm2 ) or cadaveric (11.0-14.9 mm2 ) measurements while MRI and cadaver measurements were similar at all levels. Median nerve CSA MRI measurements in CTS patients were larger than US measurements at all levels. CONCLUSION: Median nerve CSA measurements by MRI are larger than US measurements and correlated better with cadaveric measurements. Median nerve CSA criteria used for diagnosing CTS on US are not likely to be applicable to MRI.

Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes.

PURPOSE: To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. METHODS: Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. RESULTS: Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA CONCLUSION: Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. KEY POINTS: • Oblique axial imaging improves SLIL and LTIL visibility and tear detection. • This improvement is greater for the LTIL than for the SLIL ligament. • Overall, CT arthrography performed better than MR arthrography.

Ultrasound-guided synovial Tru-cut biopsy: indications, technique, and outcome in 111 cases.

OBJECTIVE: To investigate the diagnostic performance of ultrasound-guided synovial biopsy. METHODS: Clinical notes, pathology and microbiology reports, ultrasound and other imaging studies of 100 patients who underwent 111 ultrasound-guided synovial biopsies were reviewed. Biopsies were compared with the final clinical diagnosis established after synovectomy (n = 43) or clinical/imaging follow-up (n = 57) (mean 30 months). RESULTS: Other than a single vasovagal episode, no complication of synovial biopsy was encountered. One hundred and seven (96 %) of the 111 biopsies yielded synovium histologically. Pathology ± microbiology findings for these 107 conclusive biopsies comprised synovial tumour (n = 30, 28 %), synovial infection (n = 18, 17 %), synovial inflammation (n = 45, 42 %), including gouty arthritis (n = 3), and no abnormality (n = 14, 13 %). The accuracy, sensitivity, and specificity of synovial biopsy was 99 %, 97 %, and 100 % for synovial tumour; 100 %, 100 %, and 100 % for native joint infection; and 78 %, 45 %, and 100 % for prosthetic joint infection. False-negative synovial biopsy did not seem to be related to antibiotic therapy. CONCLUSION: Ultrasound-guided Tru-cut synovial biopsy is a safe and reliable technique with a high diagnostic yield for diagnosing synovial tumour and also, most likely, for joint infection. Regarding joint infection, synovial biopsy of native joints seems to have a higher diagnostic yield than that for infected prosthetic joints. KEY POINTS: • Ultrasound-guided Tru-cut synovial biopsy has high accuracy (99 %) for diagnosing synovial tumour. • It has good accuracy, sensitivity, and high specificity for diagnosis of joint infection. • Synovial biopsy of native joints works better than biopsy of prosthetic joints. • A negative synovial biopsy culture from a native joint largely excludes septic arthritis. • Ultrasound-guided Tru-cut synovial biopsy is a safe and well-tolerated procedure.

Wrist Traction During MR Arthrography Improves Detection of Triangular Fibrocartilage Complex and Intrinsic Ligament Tears and Visibility of Articular Cartilage.

OBJECTIVE: The purpose of this study was to assess the effects of traction during MR arthrography of the wrist on joint space widening, cartilage visibility, and detection of tears of the triangular fibrocartilage complex (TFCC) and intrinsic ligaments. SUBJECTS AND METHODS: A prospective study included 40 wrists in 39 patients (25 men, 14 women; mean age, 35 years). MR arthrography was performed with a 3-T MRI system with and without axial traction. Two radiologists independently measured wrist and carpal joint space widths and semiquantitatively graded articular cartilage visibility. Using conventional arthrography as the reference standard and working in consensus, they assessed for the presence of tears of the TFCC, lunotriquetral ligament (LTL), and scapholunate ligament (SLL). Visibility of a tear before traction was compared with visibility after traction. RESULTS: With traction, all joint spaces in the wrist and carpus were significantly widened (change, 0.15-1.01 mm; all p < 0.006). Subjective cartilage visibility of all joint spaces improved after traction (all p ≤ 0.048) except for that of the radioscaphoid space, which was well visualized even before traction. Conventional arthrography depicted 24 TFCC tears, seven LTL tears, and three SLL tears. The accuracy of tear detection improved after traction for the TFCC (98% after traction vs 83% before traction), the LTL (100% vs 88%), and the SLL (100% vs 95%). Tear visibility improved after traction for 54% of TFCC tears, 71% of LTL tears, and 66% of SLL tears. CONCLUSION: Wrist MR arthrography with axial traction significantly improved the visibility of articular cartilage and the detection and visibility of tears of the TFCC and intrinsic ligaments. The results favor more widespread use of traction during MR arthrography of the wrist.

Effect of upright position on tonsillar level in adolescent idiopathic scoliosis.

PURPOSE: The aim of this study was to investigate the effect of an upright position on cerebellar tonsillar level in patients with adolescent idiopathic scoliosis (AIS). METHODS: Twenty-five patients with clinically diagnosed AIS and 18 normal controls were examined in both supine and upright positions using 0.25T MRI. The position of the inferior cerebellar tonsil tip relative to a reference line connecting the basion to the opisthion (BO line) was measured in millimetres. RESULTS: None of the 18 normal control subjects had cerebellar tonsillar descent below the BO line in either supine or the upright position. Forty-eight percent of AIS patients had tonsillar descent in the upright position, compared to 28 % in the supine position. In the upright position, cerebellar tonsillar position was lower in AIS patients than in normal subjects (mean -0.7 ± 1.5 vs. +2.1 ± 1.7, p < 0.00001). AIS patients also had a large degree of tonsillar excursion between upright and supine positions compared to normal subjects (mean -1.9 ± 2.3 vs. -0.1 ± 0.2, p < 0.00001). CONCLUSIONS: When considering the theoretical likelihood that a low tonsillar position may affect spinal cord function, one should bear in mind that tonsillar descent in AIS is significantly greater in the upright position. KEY POINTS: • AIS patients exhibited greater cerebellar tonsillar descent in upright than supine position. • Cerebellar tonsillar position was lower in AIS patients than normal subjects. • AIS patients exhibited greater tonsillar excursion between supine and upright positions.

Radiological diagnosis and management of idiopathic spontaneous intra-abdominal haemorrhage (abdominal apoplexy): a case series.

PURPOSE: Idiopathic spontaneous intraperitoneal haemorrhage (ISIH), historically known as abdominal apoplexy, is spontaneous haemorrhage due to rupture of an intra-abdominal visceral vessel in the absence of trauma or underlying pathology. It is an exceptionally rare condition, with mostly scattered case reports available. The aim of this study was to describe this rare condition, possible associated risk factors, and usefulness of multislice-CT (MS-CT) angiogram in its diagnosis prior to intervention. METHODS: A retrospective review of patients diagnosed with ISIH. Radiological records of haemoperitoneum from a single tertiary hospital in 2006-2013 were analysed, and the cases of ISIH were identified. Demographics (including pre-morbid hypertension status), abdominal aortic calcification as a measure of atherosclerotic changes, MS-CT angiogram +/- conventional digital subtraction angiograph images, surgical records and outcomes were reviewed. RESULTS: 425 cases of haemoperitoneum were retrieved from hospital radiology database from 2006 to 2013, and 5 patients (1.1%) diagnosed with ISIH were identified (4 males, 1 female, mean age of 64 years). 4 out of 5 patients (80%) had a history of hypertension (mean 150/90 mmHg) and 3 patients had moderate abdominal aortic atherosclerosis. MS-CT angiogram was able to diagnose the bleeding source in 4 out of 5 patients, while the bleeding source remained occult in the last patient even with both MS-CT and traditional DSA angiography. Patients who underwent either embolization or surgery had no further re-bleeding in clinical follow up, ranging from 5 to 8 years. CONCLUSIONS: Hypertension and abdominal aortic atherosclerosis appear to be associated risk factors for ISIH, and MS-CT angiogram has a high sensitivity in detecting the site of haemorrhage. An integrated angiographic and surgical approach is important in managing patients with ISIH.

Dynamic contrast-enhanced imaging of the wrist in rheumatoid arthritis: dedicated low-field (0.25-T) versus high-field (3.0-T) MRI.

OBJECTIVE: To compare the assessment of wrist synovitis severity, synovial volume and synovial perfusion parameters on a dedicated low-field (0.25-T) to that of a high-field (3-T) whole-body MR system in patients with rheumatoid arthritis (RA). METHODS: Twenty-one patients (mean age 50.0 ± 9.8 years) with active RA were recruited prospectively. Dynamic contrast-enhanced MRI examination of the most severely affected wrist was performed at both 0.25 T and 3 T. Three MRI-derived parameters, synovitis severity (RAMRIS grade), synovial volume (ml(3)) and synovial perfusion indices (maximum enhancement and enhancement slope), were compared. RESULTS: Comparing 0.25- and 3-T MRI, there was excellent agreement for semiquantitative assessment (r: 0.80, p < 0.00001) of synovitis (RAMRIS) as well as quantitative assessment (r: 0.94, p < 0.00001) of synovial volume. Good agreement for synovial Emax (r: 0.6, p = 0.002) and fair agreement (r: 0.5, p = 0.02) for synovial Eslope was found. CONCLUSIONS: Imaging of the RA wrist at 0.25 T yields excellent correlation with 3 T with regard to the synovitis activity score (RAMRIS) and synovial volume measurement. Fair to good correlation between low- (0.25-T) and high-field (3-T) MR systems was found for perfusion parameters, being better for Emax than for Eslope.

Morphologic change in computed tomography of aldosterone-producing adenoma after radiofrequency ablation.

OBJECTIVE: To evaluate the morphologic changes of aldosterone-producing adenoma (APA) on computed tomography (CT) before and after radiofrequency ablation (RFA) and to assess the factors that are important in determining successful complete ablation of these tumours. METHOD: Between August 2004 and August 2011, 24 consecutive patients with APA undergoing CT-guided percutaneous RFA were identified from our prospective database. The pre-RFA and post-RFA CT appearances of these APAs that showed positive biochemical response were reviewed retrospectively for their 3-dimensional size, tumour volume, and CT attenuation in terms of Hounsfield units (HU). A comparison of these parameters before and after RFA was performed. RESULTS: In this study, there were 23 APAs in these 24 patients that showed biochemical cure of primary aldosteronism after RFA. When comparing post-RFA to pre-RFA CTs, there was no significant change in tumour size (14.5 mm vs 14.6 mm: P = .83) and tumour volume (1.55 cm(3) vs 1.59 cm(3); P = .41) after RFA. In nonenhanced CT images, there was no significant reduction in HU from pre-RFA to post-RFA measurements (4.4 HU vs 7.9 HU; P = .52). In contrast-enhanced CTs, there was a significant drop in HU after RFA (from 48.3 HU to 14.7 HU; P = .03). None of the included cases showed a focal region of contrast enhancement to suggest residual tumour. CONCLUSION: A change in tumour size, tumour volume, and HU in nonenhanced CT were unreliable in defining radiologic treatment success. Only changes in HU in contrast-enhanced CT was useful in confirming a positive treatment response after RFA for APA.

Next Level of Care Protocols in Radiology: Improving Patient Access to Care.

OBJECTIVE: To introduce a novel next level of care (NLC) protocol used in our breast imaging practice to bypass additional imaging and image-guided biopsy orders and to examine the impact of NLC on breast biopsy wait times compared with thyroid biopsy wait times, which do not use NLC. METHODS: Our institutional review board deemed this retrospective analysis to be exempt. NLC was implemented for breast imaging in late 2014. Two 6-month periods before and after the COVID-19 shutdown were sampled and compiled. Data were queried from departmental database and electronic health record for all breast and thyroid biopsies during this time. Time to biopsy (TTB) was defined as the number of days from the diagnostic imaging evaluation recommending the biopsy to the completion of the biopsy. To determine the effect of NLC, TTB was compared between breast and thyroid biopsies. RESULTS: Of the 1,114 breast biopsies and 154 thyroid biopsies included, the mean TTB was 9 days (95% confidence interval 8.4-9.3) for breast and 23 days (95% confidence interval 20.5-25.0) for thyroid. There was a 61% reduction in the mean TTB for patients in the breast group compared with patients in the thyroid group. The effect of the NLC was comparable among different races and ethnicities in the breast group, but a significantly higher mean TTB (24% higher, P = .025) was observed for thyroid biopsies in Black patients compared with thyroid biopsies in Hispanic patients. CONCLUSION: NLC protocol facilitates imaging evaluations and reduces the time interval to image-guided biopsies.

Glenoid bone loss: assessment with MR imaging.

PURPOSE: To investigate the agreement among magnetic resonance (MR) imaging, computed tomography (CT), and arthroscopy in the measurement of glenoid bone loss. MATERIALS AND METHODS: This study was approved by the institutional ethics committee. One hundred seventy-six patients (158 male and 18 female patients; mean age, 26.8 years ± 12.3) with anterior shoulder dislocation underwent both shoulder MR imaging and CT examination. Anterior straight line length, glenoid width, and best-fit bone loss were measured with MR imaging and CT. Sixty-five patients also underwent arthroscopy, which was used as the standard of reference. Assessment of glenoid bone loss at MR imaging was compared with that at CT and arthroscopy. Inter- and intrareader reproducibility of MR imaging-derived measurements of glenoid bone loss was evaluated. RESULTS: There was excellent correlation between CT and MR imaging with regard to anterior straight line length (r = 0.97, P < .0001), glenoid width (r = 0.95, P < .0001), and severity of glenoid bone loss-particularly with use of best-fit circle width (r = 0.83, P < .0001) rather than best-fit circle area (r = 0.82, P < .0001). In the assessment of glenoid bone loss, the correlation between CT and arthroscopy (r = 0.91, P < .0001) was marginally better than that between MR imaging and arthroscopy (r = 0.84, P < .0001). The inter- and intrareader correlations of MR imaging-derived measurements of glenoid bone loss were excellent (R = 0.90-0.95). CONCLUSION: MR imaging assessment of glenoid bone loss, particularly with use of glenoid width, is almost as accurate as CT assessment.

Pathological fracture as the presenting feature in pediatric osteosarcoma.

BACKGROUND: Pathological fracture is an uncommon presentation in patients with long bone osteosarcoma. PROCEDURES: We retrospectively reviewed the database of all patients with histologically proven osteosarcoma under the age of 18 years from 1991 to 2011 in a tertiary pediatric oncology referral center. Five patients with pathological fractures as the first presentation of osteosarcoma were identified. The treatment strategies and complications were evaluated. Ten sex-, age-, and site- matched osteosarcoma patients without pathological fracture were selected as controls. The incidence of distant metastases and outcome, including local recurrence and survival, were compared between the index (with pathological fracture) and the control (without pathological fracture) groups. RESULTS: In the index group, all five patients were boys and the mean age of onset was 13.1 years (range 9.2-14.9). Three patients (60%, 3/5) received amputation and two (40%) had wide local excision of the tumor. Pathological fracture group showed higher rate of lung (60% vs. 10%, P = 0.04) and bone (60% vs. 10%, P = 0.04) metastases at presentation, and shorter overall 5-year survival (P = 0.04) than the control group. There was no significant difference of local recurrence (20%, P = 1.00) between these two groups regardless of the type of operation. CONCLUSION: Osteosarcoma complicated by pathological fracture as first presentation had higher incidence of lung and bone metastases at presentation and worse survival rate when compared with patients without pathological fracture.

CT-guided bone biopsy with a battery-powered drill system: preliminary results.

OBJECTIVE: Standard percutaneous bone biopsy involves manual needle insertion. Recently, a battery-powered needle drilling biopsy system (OnControl) has been introduced. We report our experience using this drill biopsy system for CT-guided percutaneous bone biopsy in 25 patients. CONCLUSION: CT-guided percutaneous biopsy using the OnControl bone access system is a safe, quick, and effective method for sampling bone lesions visible on CT.

Intrinsic ligament and triangular fibrocartilage complex tears of the wrist: comparison of MDCT arthrography, conventional 3-T MRI, and MR arthrography.

PURPOSE: This study compares the diagnostic performance of multidetector CT arthrography (CTA), conventional 3-T MR and MR arthrography (MRA) in detecting intrinsic ligament and triangular fibrocartilage complex (TFCC) tears of the wrist. MATERIALS AND METHODS: Ten cadaveric wrists of five male subjects with an average age 49.6years (range 26-59years) were evaluated using CTA, conventional 3-T MR and MRA. We assessed the presence of scapholunate ligament (SLL), lunotriquetral ligament (LTL), and TFCC tears using a combination of conventional arthrography and arthroscopy as a gold standard. All images were evaluated in consensus by two musculoskeletal radiologists with sensitivity, specificity, and accuracy being calculated. RESULTS: Sensitivities/specificity/accuracy of CTA, conventional MRI, and MRA were 100%/100%/100%, 66%/86%/80%, 100%/86%/90% for the detection of SLL tear, 100%/80%/90%, 60%/80%/70%, 100%/80%/90% for the detection of LTL tear, and 100%/100%/100%, 100%/86%/90%, 100%/100%/100% for the detection of TFCC tear. Overall CTA had the highest sensitivity, specificity, and accuracy among the three investigations while MRA performed better than conventional MR. CTA also had the highest sensitivity, specificity, and accuracy for identifying which component of the SLL and LTL was torn. Membranous tears of both SLL and LTL were better visualized than dorsal or volar tears on all three imaging modalities. CONCLUSION: Both CT and MR arthrography have a very high degree of accuracy for diagnosing tears of the SLL, LTL, and TFCC with both being more accurate than conventional MR imaging.

Anterior cruciate ligament bundle measurement by MRI.

OBJECTIVE: An accurate in vivo method of measuring dimensions of the anteromedial (AM) and posterolateral (PL) anterior cruciate ligament (ACL) bundles has not been established. The purpose of this study was to measure each individual bundle using double oblique axial MR imaging of the ACL, to compare this with cadaveric measurements, and to investigate the range of measurements seen in normal subjects. MATERIALS AND METHODS: In five cadaveric knees, measurements obtained of the proximal, middle, and distal segments of each ACL bundle from double oblique axial MR images were compared with direct measurements following anatomical dissection. Thereafter, the size of both bundles from 24 normal knees was measured using an identical MR technique. Inter-observer variation was calculated using intraclass correlation. RESULTS: ACL bundle measurement in the cadaveric knees had a strong correlation (r = 0.93) with measurements obtained following anatomical dissection. No significant difference existed between measurements obtained from cadaveric knees and living normal subjects (p > 0.05). Interobserver correlation for MR measurements was excellent (R = 0.92-0.93). Overall, the long and short axis of the AM bundle were significantly larger than those of the PL bundle (p < 0.05). Also, men showed significantly larger AM and PL bundles than women (p < 0.05). Bundle size was not related to age or knee dominance. CONCLUSION: The individual ACL bundles can be accurately measured on double oblique axial MR imaging. The AM bundle is larger in caliber than the PL bundle. Both bundles are larger in men than in women and there is no significant side-to side difference.