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1.  Magnetic Resonance Imaging Predictors of Surgical Outcome in Patients with Lumbar Intervertebral Disc Herniation 
Spine  2013;38(14):1216-1225.
Study Design
A retrospective cohort design
To determine if baseline MRI findings including central/foraminal stenosis, Modic change, disc morphology, facet arthropathy, disc degeneration, nerve root impingement, and thecal sac compression are associated with differential surgical treatment effect.
Summary of Background Data
Intervertebral Disc Herniation (IDH)remains the most common source of lumbar radiculopathy treated either with discectomy or non-operative intervention. Although MRI remains the reliable gold standard for diagnosis, uncertainty surrounds the relationship between MRI findings and treatment outcomes.
Three-hundred-and-seven “complete” images from patients enrolled in a previous trial were de-identified and evaluated by one of 4 independent readers. Findings were compared to outcome measures including the Oswestry Disability Index. Differences in surgery and non-operative treatment outcomes were evaluated between image characteristic subgroups and TE determined by the difference in ODI scores.
The cohort was comprised of 40% females with an average age of 41.5 (±11.6), 61% of which underwent discectomy for IDH. Patients undergoing surgery with Modic type I endplate changes had worse outcomes (−26.4 versus −39.7 for none and −39.2 for type 2, p=0.002) and smaller treatment effect (−3.5 versus −19.3 for none and −15.7 for type 2, p=0.003). Those with compression >=1/3 showed the greatest improvement within the surgical group (−41.9 for >=1/3 versus −31.6 for none and −38.1 for <1/3,p=0.007), and the highest TE (−23 compared to −11.7 for none and −15.2 for <1/3, p=0.015). Furthermore, patients with minimal nerve root impingement demonstrated worse surgical outcomes(−26.5 versus −41.1 for “displaced” and −38.9 for “compressed”, p=0.016).
Among patients with IDH, those with thecal sac compression >=1/3 had greater surgical treatment effect than those with small disc herniations and Modic type I changes. Additionally, patients with nerve root “compression” and “displacement” benefit more from surgery than those with minimal nerve-root impingement.
PMCID: PMC3683115  PMID: 23429684
Intervertebral Disc Herniation; Lumbar; surgical outcome; Magnetic Resonance Imaging; Modic Change; Thecal Sac Compression
2.  Plexiform nerve sheath tumor or vascular malformation—role of advanced MR neurography and diffusion tensor imaging 
Skeletal radiology  2013;42(7):1007-1010.
The authors report a vascular malformation mimicking a plexiform peripheral nerve sheath tumor. Three Tesla magnetic resonance neurography with high-resolution anatomic and advanced functional diffusion tensor imaging was helpful in evaluating full extent of the lesion and characterizing its internal architecture.
PMCID: PMC3991119  PMID: 23519761
Vascular Malformation; Magnetic Resonance Neurography; Nerve Sheath Tumor
3.  Inhibition of TGF–β signaling in subchondral bone mesenchymal stem cells attenuates osteoarthritis 
Nature medicine  2013;19(6):704-712.
Osteoarthritis is a highly prevalent and debilitating joint disorder. There is no effective medical therapy for osteoarthritis due to limited understanding of osteoarthritis pathogenesis. We show that TGF–β1 is activated in the subchondral bone in response to altered mechanical loading in an anterior cruciate ligament transection (ACLT) osteoarthritis mouse model. TGF–β1 concentrations also increased in human osteoarthritis subchondral bone. High concentrations of TGF–β1 induced formation of nestin+ mesenchymal stem cell (MSC) clusters leading to aberrant bone formation accompanied by increased angiogenesis. Transgenic expression of active TGF–β1 in osteoblastic cells induced osteoarthritis. Inhibition of TGF–β activity in subchondral bone attenuated degeneration of osteoarthritis articular cartilage. Notably, knockout of the TGF–β type II receptor (TβRII) in nestin+ MSCs reduced development of osteoarthritis in ACLT mice. Thus, high concentrations of active TGF–β1 in the subchondral bone initiated the pathological changes of osteoarthritis, inhibition of which could be a potential therapeutic approach.
PMCID: PMC3676689  PMID: 23685840
4.  Sports Health Orthopaedic Magnetic Resonance Imaging Challenge 
Sports Health  2012;4(3):261-263.
PMCID: PMC3435933  PMID: 23016097
5.  MR Neurography: Advances 
High resolution and high field magnetic resonance neurography (MR neurography, MRN) is shown to have excellent anatomic capability. There have been considerable advances in the technology in the last few years leading to various feasibility studies using different structural and functional imaging approaches in both clinical and research settings. This paper is intended to be a useful seminar for readers who want to gain knowledge of the advancements in the MRN pulse sequences currently used in clinical practice as well as learn about the other techniques on the horizon aimed at better depiction of nerve anatomy, pathology, and potential noninvasive evaluation of nerve degeneration or regeneration.
PMCID: PMC3622412  PMID: 23589774
6.  High resolution imaging of tunnels by magnetic resonance neurography 
Skeletal radiology  2011;41(1):15-31.
Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment.
PMCID: PMC3158963  PMID: 21479520
MRI; MR neurography; Peripheral nerve; Tunnels; 3T
7.  Case Report: Bilateral Proximal Epiphyseal Clavicular Stress-related Lesions in a Male Gymnast 
Stress lesions of the upper extremity are relatively uncommon, and physeal stress lesions of the clavicle are rare. We present a case of bilateral physeal stress-related lesions of the proximal clavicular growth plate near the sternoclavicular joint in an adolescent male gymnast.
Case Description
A 13-year-old gymnast presented with a 3-week history of insidious onset of pain in the proximal clavicular area of his left shoulder. He had no pain at rest or at night. He recently had added a new maneuver to his routine. His radiographs were normal, but further study with CT scanning confirmed a stress lesion of his proximal clavicular physis. The lesion healed with time, and he returned to gymnastics with no symptoms. Approximately 5 months after the initial symptoms on the left side, he felt a pop and immediate pain in his right sternoclavicular joint area while doing a routine. Imaging revealed a chronic stress lesion of the proximal physis similar to that of the other side. The patient achieved healing with rest and returned to gymnastics with no limitations.
Literature Review
Physeal stress-related lesions of the proximal clavicular physis have not been reported in the literature.
Purpose and Clinical Relevance
Medial clavicle pain in adolescent gymnasts may be secondary to stress-related lesions of the proximal clavicular growth plate. Such lesions are rare.
PMCID: PMC3237983  PMID: 22045068
8.  A Quantitative Method to Assess Focal Acetabular Overcoverage Resulting From Pincer Deformity Using CT Data 
Current assessment techniques for focal acetabular overcoverage are neither consistent nor quantitatively accurate.
We propose: (1) a method to precisely quantify the amount of focal acetabular overcoverage in a patient’s pincer deformity based on CT data; (2) to evaluate the consistency of this method; and (3) to compare the method with conventional radiographic assessments.
We developed a method to assess focal acetabular overcoverage using points selected from CT scans along the acetabular rim after realigning the pelvis into a neutral position. Using four resampled and segmented pelvic CT scans of cadaveric specimens with virtually induced impingement, two observers independently tested the algorithm’s consistency. Our algorithm assessed the amount of focal acetabular overcoverage using CT data and projected data from reconstructed radiographs.
(1) We successfully showed the feasibility of the software to produce consistent, quantitative measurements. (2) Testing showed the average difference between observers in aligning the pelvis was 0.42°, indicative of a consistent approach. (3) Differences between measurements on three-dimensional (3-D) CT and simulated radiographs were significant.
The proposed method represents a new avenue in consistently quantifying focal acetabular overcoverage using CT models while correcting for pelvic tilt and rotation. Our analysis confirms AP hip radiograph simulations overestimate the amount of overhanging acetabular rim in a pincer deformity.
Clinical Relevance
This technique has potential to improve preoperative diagnostic accuracy and enhance surgical planning for correction of a pincer deformity resulting from focal acetabular overcoverage.
PMCID: PMC3171557  PMID: 21748515
9.  Talbot phase-contrast X-ray imaging for the small joints of the hand 
Physics in medicine and biology  2011;56(17):5697-5720.
A high resolution radiographic method for soft tissues in the small joints of the hand would aid in the study and treatment of Rheumatoid Arthritis (RA) and Osteoarthritis (OA), which often attacks these joints. Of particular interest would be imaging with <100 μm resolution the joint cartilage, whose integrity is a main indicator of disease. Differential phase-contrast or refraction based X-ray imaging (DPC) with Talbot grating interferometers could provide such a method, since it enhances soft tissue contrast and it can be implemented with conventional X-ray tubes. A numerical joint phantom was first developed to assess the angular sensitivity and spectrum needed for a hand DPC system. The model predicts that due to quite similar refraction indexes for joint soft tissues, the refraction effects are very small, requiring high angular resolution. To compare our model to experiment we built a high resolution bench-top interferometer using 10 μm period gratings, a W anode tube and a CCD based detector. Imaging experiments on animal cartilage and on a human finger support the model predictions. For instance, the estimated difference between the index of refraction of cartilage and water is of only several percent at ~25 keV mean energy, comparable to that between the linear attenuation coefficients. The potential advantage of DPC imaging comes thus mainly from the edge enhancement at the soft tissue interfaces. Experiments using a cadaveric human finger are also qualitatively consistent with the joint model, showing that refraction contrast is dominated by tendon embedded in muscle, with the cartilage layer difficult to observe in our conditions. Nevertheless, the model predicts that a DPC radiographic system for the small hand joints of the hand could be feasible using a low energy quasi-monochromatic source, such as a K-edge filtered Rh or Mo tube, in conjunction with a ~2 m long ‘symmetric’ interferometer operated in a high Talbot order.
PMCID: PMC3166798  PMID: 21841214
11.  An Online Evidence-Based Decision Support System for Distinguishing Benign from Malignant Vertebral Compression Fractures by Magnetic Resonance Imaging Feature Analysis 
Journal of Digital Imaging  2010;24(3):507-515.
Decision support systems have been used to promote the practice of evidence-based medicine. Computer-assisted diagnosis can serve as one element of evidence-based radiology. One area where such tools may provide benefit is analysis of vertebral compression fractures (VCFs), which can be a challenge in MRI interpretation. VCFs may be benign or malignant in etiology, and several MRI features may help to make this important distinction. We describe a web-based decision support system for discriminating benign from malignant VCFs as a prototype for a more general diagnostic decision support framework for radiologists. The system has three components: a feature checklist with an image gallery derived from proven reference cases, a prediction model, and a reporting mechanism. The website allows users to input the findings for a case to be interpreted using a structured feature checklist. The image gallery complements the checklist, for clarity and training purposes. The input from the checklist is then used to calculate the likelihood of malignancy by a logistic regression prediction model. Standardized report text is generated that summarizes pertinent positive and negative findings. This computer-assisted diagnosis system demonstrates the integration of three areas where diagnostic decision support can aid radiologists: first, in image interpretation, through feature checklists and illustrative image galleries; second, in feature-based prediction modeling; and third, in structured reporting. We present a diagnostic decision support tool that provides radiologists with evidence-based guidance for discriminating benign from malignant VCF. This model may be useful in other difficult-diagnosis situations and requires further clinical testing.
PMCID: PMC3092053  PMID: 20680384
Decision support; computer-assisted diagnosis; compression fracture; magnetic resonance imaging; structured reporting
12.  Prediction of transitional lumbosacral anatomy on magnetic resonance imaging of the lumbar spine 
World Journal of Radiology  2012;4(3):97-101.
AIM: To evaluate two simple angle measurements for predicting lumbosacral transitional vertebra (LSTV) in magnetic resonance imaging (MRI) studies of the spine.
METHODS: The lumbar spine MRI studies of 50 subjects with LSTV and 50 subjects with normal lumbosacral anatomy were retrospectively evaluated. In each study, the mid-sagittal T2-weighted image was used to measure the angle formed by a line parallel to the superior surface of the sacrum and a line perpendicular to the axis of the scan table (A-angle), as well as the angle formed by a line parallel to the superior endplate of the L3 vertebra and a line parallel to the superior surface of the sacrum (B-angle).
RESULTS: The total study population consisted of 100 subjects (46 males, 54 females, 51 ± 16 years old). There were no differences in age and sex between the two groups. Both A-angle and B-angle were significantly increased in subjects with LSTV compared to controls (P < 0.05). The optimal cut-off values of A-angle and B-angle for the prediction of LSTV were 39.8° (sensitivity = 80%, specificity = 80%, accuracy = 83%; 95% confidence interval = 74%-89%, P = 0.0001) and 35.9° (sensitivity = 80%, specificity = 54%, accuracy = 69%; 95% confidence interval = 59%-78%, P = 0.0005), respectively.
CONCLUSION: On sagittal MR images of the lumbar spine, an increased A-angle and/or B-angle should alert the radiologist to the presence of LSTV.
PMCID: PMC3314934  PMID: 22468190
Lumbosacral transitional vertebra; Magnetic resonance imaging; Lumbar spine; Angle; Prediction
13.  Superolateral Hoffa’s Fat Pad Edema: Association With Patellofemoral Maltracking and Impingement 
AJR. American journal of roentgenology  2010;195(6):1367-1373.
Nonelderly patients presenting with knee pain often have patellofemoral maltracking or impingement abnormalities. There is a relative paucity of literature on the incidence and significance of impingement-related edema of the superolateral aspect of Hoffa’s (infrapatellar) fat pad in these cases. Our study was designed to systematically evaluate the correlation of superolateral Hoffa’s fat pad edema with various anatomic parameters of trochlear morphology and patellar alignment.
We evaluated 50 knee MRI examinations in 47 patients for the presence of edema in superolateral Hoffa’s fat pad and associated anatomic abnormalities of the patellofemoral joint.
Of the 50 examinations, 25 (50%) showed superolateral Hoffa’s fat pad edema, and statistically significant differences were seen between those with and without edema with respect to sex (6/22 men vs 19/28 women) and patellar tendon patellar–length ratio (1.3 ± 0.16 and 1.1 ± 0.12 for those with and without edema, respectively).
The findings in our study suggest that edema in superolateral Hoffa’s fat pad may be an important indicator of underlying patellofemoral maltracking or impingement in younger, symptomatic patients.
PMCID: PMC3094907  PMID: 21098197
Hoffa’s fat pad edema; infrapatellar fat pad; malalignment; patellofemoral impingement
15.  A systematised MRI approach to evaluating the patellofemoral joint 
Skeletal radiology  2010;40(4):375-387.
Knee pain in young patients is a common indication for knee MRI. Many static and dynamic internal derangements of the patellofemoral joint in these patients lead to various secondary MRI findings. This article focuses on how to systematically approach, detect, and emphasize the importance of these findings in the diagnosis of patellofemoral tracking and impingement syndromes with relevant case examples.
PMCID: PMC2919651  PMID: 20217407
Patellofemoral; Impingement; Maltracking; MRI
16.  Subscapularis Strain From Swinging a Baseball Bat in an Adolescent With Closed Physis 
Sports Health  2011;3(3):283-286.
A healthy 16-year-old female baseball player was referred by her pediatrician for evaluation of pain in her right, dominant shoulder. The pain had begun insidiously 4 weeks previously after several sessions of batting practice and had worsened until she could not participate in baseball, even with low doses of ibuprofen. She was not participating in any other sports or weight lifting and had had no previous incidents of shoulder pain, but she did have a history of being able to voluntarily subluxate the right shoulder since she was a child. Her voluntary shoulder subluxation and reduction did not reproduce or worsen her pain. Results from her physical examination and radiographs were normal. Magnetic resonance imaging showed edema in the subscapularis muscle consistent with acute muscle strain. She was treated with 6 weeks of rest, ice, and anti-inflammatory medication as needed. She returned to baseball and hitting during the following 6 weeks with no limitations.
PMCID: PMC3445160  PMID: 23016019
rotator cuff; baseball; muscle strain; adolescent; subscapularis
17.  Perk Station – Percutaneous Surgery Training and Performance Measurement Platform 
Image-guided percutaneous (through the skin) needle-based surgery has become part of routine clinical practice in performing procedures such as biopsies, injections and therapeutic implants. A novice physician typically performs needle interventions under the supervision of a senior physician; a slow and inherently subjective training process that lacks objective, quantitative assessment of the surgical skill and performance[S1]. Shortening the learning curve and increasing procedural consistency are important factors in assuring high-quality medical care.
This paper describes a laboratory validation system, called Perk Station, for standardized training and performance measurement under different assistance techniques for needle-based surgical guidance systems. The initial goal of the Perk Station is to assess and compare different techniques: 2D image overlay, biplane laser guide, laser protractor and conventional freehand. The main focus of this manuscript is the planning and guidance software system developed on the 3D Slicer platform, a free, open source software package designed for visualization and analysis of medical image data.
The prototype Perk Station has been successfully developed, the associated needle insertion phantoms were built, and the graphical user interface was fully implemented. The system was inaugurated in undergraduate teaching and a wide array of outreach activities. Initial results, experiences, ongoing activities and future plans are reported.
PMCID: PMC2817987  PMID: 19539446
Image Guidance; Needle Placement; Augmented Reality; Surgical Training
18.  Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system 
Acta Neurochirurgica  2010;153(3):589-596.
Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement.
Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group.
Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques.
Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.
PMCID: PMC3040822  PMID: 21153669
Minimally invasive; Electromagnetic field navigation; Pedicle screw; Fluoroscopy; Accuracy
19.  Soft-Tissue Masses and Masslike Conditions: What Does CT Add to Diagnosis and Management? 
AJR. American journal of roentgenology  2010;194(6):1559-1567.
Although MRI is the technique of choice for evaluating most soft-tissue masses, CT often provides valuable complementary information. Specifically, there are distinguishing CT characteristics that can suggest a specific diagnosis, including the lesion’s mineralization pattern, density, pattern of adjacent bone involvement, and degree and pattern of vascularity.
This article provides an overview of the CT evaluation of soft-tissue masses, emphasizing a differential diagnosis based on these CT features.
PMCID: PMC2884142  PMID: 20489097
characterization; CT; musculoskeletal imaging; soft-tissue mass
20.  Reliability of Readings of Magnetic Resonance Imaging Features of Lumbar Spinal Stenosis 
Spine  2008;33(14):1605-1610.
Study Design
A reliability assessment of standardized magnetic resonance imaging (MRI) interpretations and measurements.
To determine the intra- and inter-reader reliability of MRI features of lumbar spinal stenosis (SPS), including severity of central, subarticular, and foraminal stenoses, grading of nerve root impingement, and measurements of cross-sectional area of the spinal canal and thecal sac.
Summary of Background Data
MRI is commonly used to assess patients with spinal stenosis. Although a number of studies have evaluated the reliability of certain MRI characteristics, comprehensive evaluation of the reliability of MRI readings in spinal stenosis is lacking.
Fifty-eight randomly selected MR images from patients with SPS enrolled in the Spine Patient Outcomes Research Trial were evaluated. Qualitative ratings of imaging features were performed according to defined criteria by 4 independent readers (3 radiologists and 1 orthopedic surgeon). A sample of 20 MRIs was reevaluated by each reader at least 1 month later. Weighted κ statistics were used to characterize intra- and inter-reader reliability for qualitative rating data. Separate quantitative measurements were performed by 2 other radiologists. Intraclass correlation coefficients and summaries of measurement error were used to characterize reliability for quantitative measurements.
Intra-reader reliability was higher than interreader reliability for all features. Inter-reader reliability in assessing central stenosis was substantial, with an overall κ of 0.73 (95% CI 0.69-0.77). Foraminal stenosis and nerve root impingement showed moderate to substantial agreement with overall κ of 0.58 (95% CI 0.53-0.63) and 0.51 (95% CI 0.42-0.59), respectively. Subarticular zone stenosis yielded the poorest agreement (overall κ 0.49; 95% CI 0.42-0.55) and showed marked variability in agreement between reader pairs. Quantitative measures showed inter-reader intraclass correlation coefficients ranging from 0.58 to 0.90. The mean absolute difference between readers in measured thecal sac area was 128 mm2 (13%).
The imaging characteristics of spinal stenosis assessed in this study showed moderate to substantial reliability; future studies should assess whether these findings have prognostic significance in SPS patients.
PMCID: PMC2754786  PMID: 18552677
spinal stenosis; MRI; reliability
21.  Reliability of Magnetic Resonance Imaging Readings for Lumbar Disc Herniation in the Spine Patient Outcomes Research Trial (SPORT) 
Spine  2008;33(9):991-998.
Study Design
Assessment of the reliability of standardized magnetic resonance imaging (MRI) interpretations and measurements.
To determine the intra- and inter-reader reliability of MRI parameters relevant to patients with intervertebral disc herniation (IDH), including disc morphology classification, degree of thecal sac compromise, grading of nerve root impingement, and measurements of cross-sectional area of the spinal canal, thecal sac, and disc fragment.
Summary of Background Data
MRI is increasingly used to assess patients with sciatica and IDH, but the relationship between specific imaging characteristics and patient outcomes remains uncertain. Although other studies have evaluated the reliability of certain MRI characteristics, comprehensive evaluation of the reliability of readings of herniated disc features on MRI is lacking.
Sixty randomly selected MR images from patients with IDH enrolled in the Spine Patient Outcomes Research Trial were each rated according to defined criteria by 4 independent readers (3 radiologists and 1 orthopedic surgeon). Quantitative measurements were performed separately by 2 other radiologists. A sample of 20 MRIs was re-evaluated by each reader at least 1 month later. Agreement for rating data were assessed with kappa statistics using linear weights. Reliability of the quantitative measurements was assessed using intraclass correlation coefficients (ICCs) and summaries of measurement error.
Inter-reader reliability was substantial for disc morphology [overall kappa 0.81 (95% confidence interval (CI): 0.78, 0.85)], moderate for thecal sac compression [overall kappa 0.54 (95% CI: 0.37, 0.68)], and moderate for grading nerve root impingement [overall kappa 0.47 (95% CI: 0.36, 0.56)]. Quantitative measures showed high ICCs of 0.87 to 0.96 for spinal canal and thecal sac cross-sectional areas. Measures of disc fragment area had moderate ICCs of 0.65 to 0.83. Mean absolute differences between measurements ranged from approximately 15% to 20%.
Classification of disc morphology showed substantial intra- and inter-reader agreement, whereas thecal sac and nerve root compression showed more moderate reader reliability. Quantitative measures of canal and thecal sac area showed good reliability, whereas measurement of disc fragment area showed more modest reliability.
PMCID: PMC2745940  PMID: 18427321
disc herniation; MRI; reliability study
22.  Statistical Combination Schemes of Repeated Diagnostic Test Data1 
Academic radiology  2006;13(5):566-572.
Rationale and Objectives
When diagnostic tests are repeated and combined, a number of schemes may be adopted. Guidelines for their interpretations are required.
Materials and Methods
Three combination schemes, “and” (A), “or” (O), and “majority” (M), are considered. To evaluate these schemes, dependency by specifying κ values quantifying repeated test agreement was structured. In a pilot study, the combined accuracies of magnetic resonance imaging using six different pulse sequences of medial collateral ligaments of the elbows of 28 cadavers, with eight having lesions artificially created surgically, were examined. Images were evaluated simultaneously by using a five-point ordinal scale. For each pulse sequence, individuals for whom the diagnosis varied from once to three repetitions were considered.
Scheme M improves diagnostic accuracy when sensitivity and specificity of a single test exceed 0.5, with maximal improvement at 0.79. Under scheme A, sensitivity decreases to 0.38–0.59. Under scheme O, sensitivity increases to 0.53–0.79. Scheme M yields a small improvement, reaching 0.50–0.71. Under scheme A, specificity increases to 0.95–0.98. Under scheme O, specificity decreases to 0.91–0.98. Scheme M also yields a small improvement, reaching 0.94–0.98.
Scheme A is recommended for ruling in diagnoses, scheme O is recommended for ruling out diagnoses, and scheme M is neutral. Consequently, different schemes may be used to optimize the target diagnostic accuracy.
PMCID: PMC1475743  PMID: 16627197
Elbow ligament; magnetic resonance (MR) imaging; κ statistic; sensitivity; specificity; repeated diagnostic test
23.  Picture Archiving and Communication System and its Impact on Image Viewing in Physical Therapy Practice 
Journal of Digital Imaging  2006;19(4):346-350.
Imaging plays an increasing role in physical therapy (PT) practice. We sought to determine if picture archiving and communication system (PACS) deployment would increase the proportion of imaging studies viewed by physical therapists (PTs) at the point of care and to assess PTs' perception of the value of access to imaging information. The study was performed in a 720-bed urban teaching hospital where an average of 2,000 rehabilitation visits per month are performed by 12 PTs. We compared the proportion of imaging studies viewed by PTs before and after PACS implementation. We surveyed PTs to assess their perception on the value of access to imaging studies. Film library records pre-PACS and web server audit trail post-PACS implementation were reviewed to measure access. Chi-square was used to compare proportions and trends. During the 3-month period before PACS usage, PTs viewed 1% (6/505) of imaging studies, citing time as the primary barrier. Post-PACS, the proportion of imaging studies viewed rose from 28% (95/344, second month) to 84% (163/192, fifth month) (p < 0.0001, chi-square). Most PTs believed that access to imaging studies has high value and has a positive impact on clinical practice. Physical therapists rarely viewed imaging studies before PACS due to time barriers. They viewed more imaging studies (84%) post-PACS and felt that access to imaging studies has a positive impact on clinical practice. Further studies are needed to assess whether PACS enhances PTs' clinical decision making and improves patient outcomes.
PMCID: PMC3045163  PMID: 16826336
Evidence-based practice; PACS; Filmless; Physical therapy
24.  Incidental Vertebral Fractures on Chest Radiographs 
Recognition of incidental vertebral fractures may be an important opportunity for identifying and treating osteoporosis.
To assess osteoporosis documentation rates in patients with vertebral fractures, and to define patient and hospitalization characteristics associated with osteoporosis management.
Hospital and outpatient records were abstracted for patients with vertebral fractures on inpatient radiograph reports. The primary outcome of interest was discharge summary fracture documentation. Covariates associated with fracture documentation and treatment were examined with multivariate regression models. Secondary outcomes included osteoporosis documentation and management 6 months following discharge.
Women ≥50 years hospitalized at an academic medical center.
Among 10,291 women with chest radiographs, 142 (1.4%) had vertebral fractures reported. Among patients with a reported fracture, 58 (41%) had their fracture noted in the findings section but not in the final impression. Only 23 (16%) discharge summaries documented a vertebral fracture. Factors associated with documentation of the fracture in the discharge summary included notation of the fracture in the impression section (odds ratio [OR] 3.7, 95% confidence interval [CI] 1.0 to 13.1), tobacco use (OR 3.7; 95% CI 1.1 to 12.2), discharge from a medical service (OR 7.6; 95% CI 0.9 to 66.2) and glucocorticoid use (OR 3.7; 95% CI 0.8 to 17.0). Only 36% of patients were using any osteoporosis medications at discharge. Fracture notation in the impression section was associated with fracture documentation in subsequent outpatient notes (OR 3.6, 95% CI 0.9 to 13.8). Discharge summary fracture documentation was associated with an increased likelihood of starting an osteoporosis medication by 6 months (OR 2.8; 95% CI 0.8 to 9.2).
Incidental vertebral fractures from inpatient chest radiographs may represent a missed opportunity for osteoporosis management.
PMCID: PMC1484720  PMID: 16686811
diagnosis; osteoporosis; health service research; women's health; hospital medicine
25.  SCAR R&D Symposium 2003: Comparing the Efficacy of 5-MP CRT Versus 3-MP LCD in the Evaluation of Interstitial Lung Disease  
Journal of Digital Imaging  2004;17(3):149-157.
The efficacy of two medical-grade, self-calibrating, gray scale displays were compared with regard to impact on sensitivity and specificity for the detection of interstitial lung disease (ILD) on computed radiographs (CR). The displays were a 5-megapixel (MP) cathode ray tube (CRT) device and a 3-MP liquid crystal display (LCD). A sample consisting of 230 anteroposterior (AP), posteroanterior (PA), and lateral views of the chest with CT-proven findings characteristic for ILD as well as 80 normal images were compared. This double-blinded trial produced a sample sufficient to detect if the sensitivity of the LCD was 10% or more reduced (one-sided) from the “gold standard” CRT display. Both displays were calibrated to the DICOM gray scale standard and the coefficient of variation of the luminance function varied less than 2% during the study. Five board-certified radiologists specializing in thoracic radiology interpreted the sample on both displays and the intraobserver Az (area under the ROC curve) showed no significant correlation to the display used. In addition, an interobserver kappa analysis showed that the relative disagreement between any observer pair remained relatively constant between displays, and thus was display invariant. This study demonstrated there is no significant change in observer performance sensitivity on 5-MP CRT versus 3-MP LCD displays for CR examinations demonstrating ILD of the chest.
PMCID: PMC3046602  PMID: 15534750
ROC; kappa; image quality; displays; interstitial lung disease; receiver operating characteristic

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