Negative predictive value of CT for occult fractures of the hip and pelvis with imaging follow-up.

PURPOSE: To determine the negative predictive value of multidetector CT for radiographically occult fracture of the hip or pelvis in an elderly population presenting to the emergency department. METHODS: Two hundred thirty-seven elderly patients with suspected fracture were identified over a 5-year period with negative radiographs acquired in the emergency department followed by an index CT of the hip/pelvis within 24 h. There were 81 cases with a negative index CT, as determined by 2 musculoskeletal radiologists, and with some form of imaging follow-up (MRI, CT, or x-ray) performed within 18 months of the index CT. Follow-up imaging was reviewed by 2 musculoskeletal radiologists for the presence of fracture to determine the performance of the index CT. The electronic medical record was used to exclude the possibility of intervening trauma between the time of the index CT and follow-up imaging. RESULTS: There were 39 cases with follow-up imaging performed within 6 weeks of the negative index CT, and 42 with follow-up imaging within 6 weeks to 18 months of the negative index CT. Eight of 81 patients demonstrated a fracture on follow-up imaging, with 3 of 8 involving the femoral neck or intertrochanteric femur. The negative predictive value of the index CT for the detection of a radiographically occult hip or pelvic fracture was 90.1%. If considering only surgically relevant fractures (femoral neck and intertrochanteric fractures), the negative predictive value improved to 96.3%. CONCLUSION: Computed tomography for occult hip fractures has a high negative predictive value but there are cases not detected with surgical implications.

Stiffness of the human foot and evolution of the transverse arch.

The stiff human foot enables an efficient push-off when walking or running, and was critical for the evolution of bipedalism1-6. The uniquely arched morphology of the human midfoot is thought to stiffen it5-9, whereas other primates have flat feet that bend severely in the midfoot7,10,11. However, the relationship between midfoot geometry and stiffness remains debated in foot biomechanics12,13, podiatry14,15 and palaeontology4-6. These debates centre on the medial longitudinal arch5,6 and have not considered whether stiffness is affected by the second, transverse tarsal arch of the human foot16. Here we show that the transverse tarsal arch, acting through the inter-metatarsal tissues, is responsible for more than 40% of the longitudinal stiffness of the foot. The underlying principle resembles a floppy currency note that stiffens considerably when it curls transversally. We derive a dimensionless curvature parameter that governs the stiffness contribution of the transverse tarsal arch, demonstrate its predictive power using mechanical models of the foot and find its skeletal correlate in hominin feet. In the foot, the material properties of the inter-metatarsal tissues and the mobility of the metatarsals may additionally influence the longitudinal stiffness of the foot and thus the curvature-stiffness relationship of the transverse tarsal arch. By analysing fossils, we track the evolution of the curvature parameter among extinct hominins and show that a human-like transverse arch was a key step in the evolution of human bipedalism that predates the genus Homo by at least 1.5 million years. This renewed understanding of the foot may improve the clinical treatment of flatfoot disorders, the design of robotic feet and the study of foot function in locomotion.

Three-Dimensional Isotropic MRI of the Cervical Spine: A Diagnostic Comparison With Conventional MRI.

STUDY DESIGN: Retrospective diagnostic trial. OBJECTIVE: To determine the diagnostic performance of 3-dimensional turbo spin-echo (3D-TSE) isotropic magnetic resonance imaging (MRI) in the assessment of cervical spine pathology. SUMMARY OF BACKGROUND DATA: MRI is the imaging modality of choice for many cervical spine pathologies. However, axial imaging may be suboptimal if the image plane is oriented differently than the plane of interest, due to lordosis, kyphosis, or deformity. 3D-TSE isotropic MRI is a promising novel technology that bypasses this limitation by enabling dynamic image reformation in any desired orientation. METHODS: Forty-eight patients who underwent 3D-TSE and conventional 2-dimensional fast spin-echo (2D-FSE) T2-weighted cervical spine MRI at our institution were randomly selected. 3D-TSE and 2D-FSE sequences from each subject were independently evaluated by 2 orthopedic spine surgeons and 4 musculoskeletal radiologists. Images were assessed using specific pilot-tested criteria for stenosis, herniation, and degenerative changes. Intermethod, interrater, and intrarater agreements for 3D-TSE and 2D-FSE, and Fleiss κ coefficients were determined. RESULTS: The overall intermethod agreement was 80.7%. The interrater agreement was 75.9% for 3D-TSE and 75.7% for 2D-FSE (P=0.47). The intrarater agreement was 82.2% for 3D-TSE and 81.5% for 2D-FSE (P=0.71). Fleiss κ coefficients were 0.42 for 3D-TSE and 0.43 for 2D-FSE (P=0.62), indicating moderate interrater reliability. The intermethod agreement and the 2D-FSE intrarater agreement were statistically similar (P=0.49). CONCLUSIONS: There is a high degree of agreement between 3D-TSE and 2D-FSE MRI in assessing the cervical spine. The intermethod variability was statistically similar to the intrinsic intrarater variability of 2D-FSE MRI. This study demonstrates that 3D-TSE yields at least equivalent diagnostic information as conventional 2D-FSE in the cervical spine. In addition, reviewers noted subjective advantages of 3D-TSE image reprocessing, especially when evaluating greater pathology or deformity, with a simplified image acquisition process.

Comparison of agreement of cervical spine degenerative pathology findings in magnetic resonance imaging studies.

BACKGROUND CONTEXT: Magnetic resonance imaging (MRI) is often used in the evaluation of degenerative conditions of the cervical spine. However, the agreement of interpreting and reporting varying degenerative findings on cervical MRI has not been well assessed. PURPOSE: This study aimed to compare the inter-rater and intra-rater agreement of MRI findings between common degenerative findings of the cervical spine. STUDY DESIGN: A retrospective diagnostic study was used as study design. PATIENT SAMPLE: The sample consisted of 48 patients who underwent routine cervical spine MRI at our institution between January 2011 and June 2012. OUTCOME MEASURES: Reviewers evaluated each MRI study at each vertebral level for disc hydration, disc space height, central stenosis, foraminal stenosis, end plate changes, spondylolisthesis, and cord signal change. METHODS: A panel of two orthopedic spine surgeons and four musculoskeletal radiologists independently reviewed 48 sets of T2-weighted axial and sagittal MRI sequences for a series of preselected criteria, and their findings were compared with those of the other panelists to determine inter-rater agreement. Each panelist also re-reviewed the first 10 studies to determine intra-rater agreement. Absolute inter-rater and intra-rater agreements were then calculated and compared for different findings. A modified analysis ignored disagreements between the least severe grades of findings to determine the inter-rater and intra-rater agreements of the most clinically important severity grades. RESULTS: Absolute inter-rater agreement ranged from 54.6% to 95.0%. Disc hydration (54.6%), central stenosis (72.7%), and foraminal stenosis (73.1%) demonstrated the lowest inter-rater agreement, whereas spondylolisthesis (95.0%) and cord signal change (92.9%) demonstrated the highest agreement. The modified analysis found better inter-rater agreement, ranging from 80.9% to 95.0%. Absolute intra-rater agreement ranged from 74.2% to 94.7%. The modified analysis again found better agreement, ranging from 85.0% to 94.7%. As would be expected, overall intra-rater agreement (81.6%, 95% CI 78.9%-84.3%) was higher than inter-rater agreement (75.7%, 95% CI 74.4%-77.0%). The clinical specialty of the reviewer had no significant impact on inter- or intra-rater agreement. CONCLUSIONS: MRI findings play an important role in the management of patients with cervical spine conditions. For this reason, consistent descriptions of these findings are essential and physicians should be aware of the relative reliability of these findings. This systematic study developed standardized grading criteria and nomenclature for common clinically significant MRI findings in the cervical spine. Even in this optimized research setting, we found significant ranges in agreement across these MRI findings. In the clinical setting, inter- and intra-rater agreements may be lower, and the range of agreements between findings may be greater. Physicians should be aware of inconsistencies inherent in the interpretation of cervical MRI findings and should be aware that some findings demonstrate lower agreement than others.

3D-FSE Isotropic MRI of the Lumbar Spine: Novel Application of an Existing Technology.

STUDY DESIGN: Retrospective diagnostic trial. OBJECTIVE: To determine the diagnostic performance of 3-dimensional isotropic fast/turbo spin-echo (3D-TSE) in routine lumbar spine magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Conventional 2-dimensional fast spin-echo (2D-FSE) MRI requires independent acquisition of each desired imaging plane. This is time consuming and potentially problematic in spine imaging, as the plane of interest varies along the vertical axis due to lordosis, kyphosis, or possible deformity. 3D-TSE provides the capability to acquire volumetric data sets that can be dynamically reformatted to create images in any desired plane. METHODS: Eighty subjects scheduled for routine lumbar MRI were included in a retrospective trial. Each subject underwent both 3D-TSE and conventional 2D-FSE axial and sagittal MRI sequences. For each subject, the 3D-TSE and 2D-FSE sequences were separately evaluated (minimum 4 wk apart) in a randomized order and read independently by 4 reviewers. Images were evaluated using specific criteria for stenosis, herniation, and degenerative changes. RESULTS: The intermethod reliability for the 4 reviewers was 85.3%. Modified intermethod reliability analysis, disregarding disagreements between the lowest 2 descriptors for appropriate criteria (equivalent to "none" and "mild"), revealed average overall agreement of 94.6%. Using the above, modified criteria, interobserver variability for 3D-TSE was 89.1% and 88.3% for 2D-FSE (P=0.05), and intraobserver variability for 3D-TSE was 87.2% and 82.0% for 2D-FSE (P<0.01). The intermethod agreement between 3D-TSE and 2D-FSE was statistically noninferior to intraobserver 2D-FSE variability (P<0.01). CONCLUSIONS: This systematic evaluation showed that there is a very high degree of agreement between diagnostic findings assessed on 3D-TSE and conventional 2D-FSE sequences. Overall, intermethod agreement was statistically noninferior to the intraobserver agreement between repeated 2D-FSE evaluations. Overall, this study shows that 3D-TSE performs equivalently, if not superiorly to 2D-FSE sequences. Reviewers found particular utility for the ability to manipulate image planes with the 3D-TSE if there was greater pathology or anatomic variation.

Tarsal Coalitions: Radiographic, CT, and MR Imaging Findings.

BACKGROUND: Tarsal coalitions affect up to 13% of the population and can be a cause of chronic ankle and hindfoot pain. They can be subdivided as osseous, cartilaginous, or fibrous types, each with unique radiographic, CT, and MR imaging findings. In particular, MR imaging offers the unique ability to determine the exact type of tarsal coalition that is present as well as whether any associated soft tissue abnormalities are present. QUESTIONS/PURPOSES: The purposes of this paper were to (1) review the anatomy of the hindfoot; (2) review the radiographic, CT, and MR imaging findings of tarsal coalitions; and (3) review the imaging appearance of the specific types of tarsal coalitions. METHODS: Online searches were performed using Google Scholar with the search criteria of "tarsal coalition," "hindfoot anatomy," and "subtalar coalition," and limiting the searches to papers published in the last 10 years in major radiology journals. RESULTS: The anatomy of the hindfoot is complex but essential to understand. There are various radiographic, CT, and MR imaging findings that can be consistently noted in cases of tarsal coalition. The specific types of tarsal coalition demonstrate characteristic imaging findings. CONCLUSIONS: Knowledge of the normal anatomy of the foot, in particular the hindfoot, combined with the knowledge of the imaging characteristics of different histologic subtypes of coalitions (osseous, cartilaginous, and fibrous) is essential for interpreting radiographic, CT, and MR images of the ankle and foot.

Interrater and intrarater agreements of magnetic resonance imaging findings in the lumbar spine: significant variability across degenerative conditions.

BACKGROUND CONTEXT: Magnetic resonance imaging (MRI) is frequently used in the evaluation of degenerative conditions in the lumbar spine. The relative interrater and intrarater agreements of MRI findings across different pathologic conditions are underexplored, as most studies are focused on specific findings. PURPOSE: The purpose of this study was to characterize the interrater and intrarater agreements of MRI findings used to assess the degenerative lumbar spine. STUDY DESIGN: A retrospective diagnostic study at a large academic medical center was undertaken with a panel of orthopedic surgeons and musculoskeletal radiologists to assess lumbar MRIs using standardized criteria. PATIENT SAMPLE: Seventy-five subjects who underwent routine lumbar spine MRI at our institution were included. OUTCOME MEASURES: Each MRI study was assessed for 10 lumbar degenerative findings using standardized criteria. Lumbar vertebral levels were assessed independently, where applicable, for a total of 52 data points collected per study. METHODS: T2-weighted axial and sagittal MRI sequences were presented in random order to the four reviewers (two orthopedic spine surgeons and two musculoskeletal radiologists) independently to determine interrater agreement. The first 10 studies were reevaluated at the end to determine intrarater agreement. Images were assessed using standardized and pilot-tested criteria to assess disc degeneration, stenosis, and other degenerative changes. Interrater and intrarater absolute percent agreements were calculated. To highlight the most clinically important MRI disagreements, a modified agreement analysis was also performed (in which disagreements between the lowest two severity grades for applicable conditions were ignored). Fleiss kappa coefficients for interrater agreement were determined. RESULTS: The overall absolute and modified interrater agreements were 76.9% and 93.5%, respectively. The absolute and modified intrarater agreements were 81.3% and 92.7%, respectively. Average Fleiss kappa coefficient was 0.431, suggesting moderate overall agreement. However, when stratified by condition, absolute interrater agreement ranged from 65.1% to 92.0%. Disc hydration, disc space height, and bone marrow changes exhibited the lowest absolute interrater agreements. The absolute intrarater agreement had a narrower range, from 74.5% to 91.5%. Fleiss kappa coefficients ranged from fair-to-substantial agreement (0.282-0.618). CONCLUSIONS: Even in a study using standardized evaluation criteria, there was significant variability in the interrater and intrarater agreements of MRI in assessing different degenerative conditions of the lumbar spine. Clinicians should be aware of the condition-specific diagnostic limitations of MRI interpretation.

Impact of velaglucerase alfa on bone marrow burden score in adult patients with type 1 Gaucher disease: 7-year follow-up.

BACKGROUND: Bone marrow infiltration by substrate-engorged "Gaucher" cells manifests early in Gaucher disease (GD). The impact of velaglucerase alfa on bone marrow burden (BMB) was evaluated as an exploratory assessment. METHODS: BMB scores were assessed using T1- and T2-weighted magnetic resonance images of the lumbar spine (LS) and femora among symptomatic GD patients who participated in the 9-month Phase I/II trial and long-term extension study for velaglucerase alfa. A post-hoc assessment of marrow involvement was performed. BMB scores per site are 0-8 (0/1=normal; 8=severe infiltration). RESULTS: The median LS-BMB score at baseline was 6 (n=12; range 3-8); at 9 months, compared with baseline, there was a median change of -2 (n=11; two-sided p-value=0.0078). LS-BMB scores continued to decrease through 5 years (n=8; median change from baseline -5 [p=0.0078], median score 1 [range 1-4]) and were subsequently sustained through 7 years (n=8). LS-BMB decreases of ≥2 points occurred in 6/11 patients at 9 months, and in all assessable patients (8/8) by 5 years. Long-term femoral BMB (F-BMB) assessment was possible for three patients; all experienced reductions of ≥2 points at 5 years with a total score (LS-BMB+F-BMB) decrease ≥4. CONCLUSIONS: This post hoc analysis suggests improvement in BMB scores through 5 years that was sustained through 7 years, despite dose reduction from 15 months. Prospective studies in a large cohort are needed to validate these findings.

Acetabular fractures: anatomic and clinical considerations.

OBJECTIVE: Classifying acetabular fractures can be an intimidating topic. However, it is helpful to remember that there are only three basic types of acetabular fractures: column fractures, transverse fractures, and wall fractures. Within this framework, acetabular fractures are classified into two broad categories: elementary or associated fractures. We will review the osseous anatomy of the pelvis and provide systematic approaches for reviewing both radiographs and CT scans to effectively evaluate the acetabulum. CONCLUSION: Although acetabular fracture classification may seem intimidating, the descriptions and distinctions discussed and shown in this article hopefully make the topic simpler to understand. Approach the task by recalling that there are only three basic types of acetabular fractures: column fractures (coronally oriented on CT images), transverse fractures (sagittally oriented on CT images), and wall fractures (obliquely oriented on CT images). We have provided systematic approaches for reviewing both conventional radiographs and CT scans to effectively assess the acetabulum. The clinical implications of the different fracture patterns have also been reviewed because it is critically important to include pertinent information for our clinical colleagues to provide the most efficient and timely clinical care.

Comparison of 3D vs. 2D fast spin echo imaging for evaluation of articular cartilage in the knee on a 3T system scientific research.

PURPOSE: We sought to retrospectively compare the accuracy of a three-dimensional fat-suppressed, fast spin-echo sequences acquired in the sagittal plane, with multiplanar reconstructions to that of two-dimensional fat-suppressed, fast spin echo sequences acquired in three planes on a 3T MR system for the evaluation of articular cartilage in the knee. MATERIALS AND METHODS: Our study group consisted of all patients (N=34) that underwent 3T MR imaging of the knee at our institution with subsequent arthroscopy over an 18-month period. There were 21 males and 13 females with an average age of 36 years. MR images were reviewed by 3 musculoskeletal radiologists, blinded to operative results. 3D and 2D sequences were reviewed at different sittings separated by 4 weeks to prevent bias. Six cartilage surfaces were evaluated both with MR imaging and arthroscopically with a modified Noyes scoring system and arthroscopic results were used as the gold standard. Sensitivity, specificity, and accuracy were calculated for each reader along with Fleiss Kappa assessment agreement between the readers. Accuracies for each articular surface were compared using a difference in proportions test with a 95% confidence interval and statistical significance was calculated using a Fisher's Exact Test. RESULTS: Two hundred and four articular surfaces were evaluated and 49 articular cartilage lesions were present at arthroscopy. For the patellofemoral surfaces, the sensitivity, specificity, and accuracy were 76.5%, 83%, and 78.2% for the 3D sequences and were 82.3%, 76%, and 82% respectively for the 2D sequences. For the medial compartment surfaces, the sensitivity, specificity, and accuracy were 81.1%, 65.1%, and 78.5% for the 3D sequences and were 82.5%, 48%, and 76.7% respectively for the 2D sequences. For the lateral compartment surfaces, the sensitivity, specificity, and accuracy were 89.3%, 39%, and 79.5% for the 3D sequences and were 94.7%, 18.8%, and 79.5% respectively for the 2D sequences. The accuracies were not significantly different between 3D and 2D sequences. Fleiss Kappa agreement values for the assessment of inter-observer agreement ranged from substantial for the patella and medial femur to moderate for the trochlea and fair for the medial tibia and lateral compartment. CONCLUSION: There was no significant difference in accuracy for the evaluation of articular cartilage of a single three-dimensional, fast spin echo sequence with multi-planar reformatted images vs. two-dimensional, fast spin echo sequences acquired in all three imaging planes in the knee.

Lipoma arborescens of the peroneal tendon sheath.

Lipoma arborescens or synovial lipomatosis is a rare disorder characterized by mature fat infiltration of hypertrophic synovial villi, most frequently affecting the suprapatellar pouch of the knee. Involvement of the synovial tendon sheath is extremely rare with only a few reported cases in the literature. We present a case of lipoma arborescens involving the peroneal and flexor tendons sheaths of the ankle, review the few reported cases to date, and discuss MR imaging features of this rare entity.

Design, implementation, and evaluation of an innovative anatomy course.

Starting in 2004, a medical school gross anatomy course faced with a 30% cut in hours went through an extensive redesign, which transformed a traditional dissection course into a course with a clinical focus, learning societies, and extensive on-line learning support. Built into the redesign process was an extensive and ongoing assessment process, which included student focus groups, faculty development, surveys, and examinations. These assessments were used formatively, to enhance the course from year to year, and summatively, to determine how well the course was meeting the new learning objectives. The assessments from focus groups and faculty development prompted changes in support structures provided to students and the training and preparation of faculty. Survey results showed that, after student satisfaction declined the first year, satisfaction increased steadily through the fourth iteration as the course gained acceptance by students and faculty alike. There was a corresponding increase in the performance of students on course examinations. An additional examination given to students one and a half and three years after their anatomy course ended demonstrated the redesigned course's long-term effectiveness for retaining anatomical knowledge and applying it to clinical cases. Compared to students who took the original course, students who took the shorter, more clinical course performed as well, or better, on each section of the examination. We attribute these positive results to the innovative course design and to the changes made based on our formative assessment program.

Imaging of anterior cruciate ligament repair and its complications.

OBJECTIVE: This article provides a review of anterior cruciate ligament (ACL) reconstruction procedures and their normal postoperative appearance. Then, we review commonly encountered complications: those associated with decreased range of motion (impingement, arthrofibrosis, intraarticular bodies, ganglion cysts) and those associated with laxity (graft tearing, graft stretching). Finally, we review some miscellaneous complications. CONCLUSION: Given the number of patients undergoing ACL reconstruction, it is important for radiologists to be familiar with the different reconstruction surgeries and their common complications.

Imaging of sports-related hip and groin injuries.

A normally functioning hip joint is imperative for athletes who use their lower extremities with running, jumping, or kicking activities. Sports-related injuries of the hip and groin are far less frequent than injuries to the more distal aspect of the extremity, accounting for less than 10% of lower extremity injuries. Despite the lower incidence, hip and groin injuries can lead to significant clinical and diagnostic challenges related to the complex anatomy and biomechanical considerations of this region. Loads up to 8 times normal body weight have been documented in the joint in common daily activities, such as jogging, with significantly greater force expected during competitive athletics. Additionally, treatment for hip and groin injuries can obviate the participation of medical and surgical specialties, with a multidisciplinary approach frequently required. Delay in diagnosis and triage of these injuries may cause loss of time from competition and, potentially, early onset of degenerative changes. Magnetic resonance imaging (MRI) of the hip has proven to be the gold standard for the diagnosis of sports-related hip and groin injuries in the setting of negative radiographs. With its exquisite soft tissue contrast, multiplanar capabilities, and lack of ionizing radiation, MRI is unmatched in the noninvasive diagnosis of intra-articular and extra-articular pathology, as well as intraosseous processes. This review focuses on MRI of common athletic injuries of the hip and groin, including acetabular labral tears, femoral acetabular impingement syndrome, muscle injuries around the hip and groin (including athletic pubalgia), and athletic osseous injuries.

Comparison of spin echo T1-weighted sequences versus fast spin-echo proton density-weighted sequences for evaluation of meniscal tears at 1.5 T.

PURPOSE: At our institution, fast spin-echo (FSE) proton density (PD) imaging is used to evaluate articular cartilage, while conventional spin-echo (CSE) T1-weighted sequences have been traditionally used to characterize meniscal pathology. We sought to determine if FSE PD-weighted sequences are equivalent to CSE T1-weighted sequences in the detection of meniscal tears, obviating the need to perform both sequences. METHOD AND MATERIALS: We retrospectively reviewed the records of knee arthroscopies performed by two arthroscopy-focused surgeons from an academic medical center over a 2-year period. The preoperative MRI images were interpreted independently by two fellowship-trained musculoskeletal radiologists who graded the sagittal CSE T1 and FSE PD sequences at different sittings with grades 1-5, where 1 = normal meniscus, 2 = probable normal meniscus, 3 = indeterminate, 4 = probable torn meniscus, and 5 = torn meniscus. Each meniscus was divided into an anterior and posterior half, and these halves were graded separately. Operative findings provided the gold standard. Receiver operating characteristic (ROC) analysis was performed to compare the two sequences. RESULTS: There were 131 tears in 504 meniscal halves. Using ROC analysis, the reader 1 area under curve for FSE PD was significantly better than CSE T1 (0.939 vs. 0.902, >95% confidence). For reader 2, the difference met good criteria for statistical non-inferiority but not superiority (0.913 for FSE PD and 0.908 for CSE T1; >95% non-inferiority for difference at most of -0.027). CONCLUSION: FSE PD-weighted sequences, using our institutional protocol, are not inferior to CSE T1-weighted sequences for the detection of meniscal tears and may be superior.

MRI characteristics and classification of peripheral vascular malformations and tumors.

Vascular malformations and tumors comprise a broad spectrum of lesions that can cause significant morbidity and even mortality in children and adults. Classification of vascular malformations into high flow and low flow has significant impact on management since the main treatment of the former is transarterial embolization and the later percutaneous sclerotherapy. Magnetic resonance imaging (MRI) is a noninvasive effective tool for imaging and classification of vascular malformations based on the presence of lobulated masses, signal voids, and hemodynamic flow characteristics. MRI also provides details about anatomic extent of the lesion, proximity to vital structures, and involvement of multiple tissue planes. The prototype of vascular tumors is infantile hemangioma with its typical involution after a proliferative phase during infancy. Hemangioma appears as a distinct intensely enhancing soft tissue mass with enlarged feeding arteries and draining veins. Less common vascular tumors include congenital hemangioma, kaposiform hemangioendothilioma, angiolipoma, angiosarcoma, and hemangiopericytoma.

Correlation of MRI-Based bone marrow burden score with genotype and spleen status in Gaucher's disease.

OBJECTIVE: The purpose of this study was to correlate skeletal pathologic findings quantified by MRI-based bone marrow burden score with genotype and spleen status and other clinical parameters, including liver size and duration of enzyme replacement therapy, in patients with Gaucher's disease. MATERIALS AND METHODS: Two radiologists retrospectively reviewed MR images of 47 patients with Gaucher's disease and determined bone marrow burden scores by consensus on the basis of previously published criteria. The bone marrow burden scores were correlated with genotype, liver volume, spleen status, age, and cumulative duration of enzyme replacement therapy. RESULTS: Subjects with compound heterozygous N370S alleles had significantly higher overall, lumbar spinal, and femoral bone marrow burden scores than did N370S homozygotes. There was a significant positive correlation between an enlarged or surgically absent spleen and bone marrow burden score. There were no significant associations between bone marrow burden score and liver volume, age, cumulative duration of enzyme replacement therapy, or cumulative duration of untreated disease. Femoral and lumbar spinal bone marrow burden scores had a weak but significant positive correlation across all patients. CONCLUSION: Skeletal pathologic findings in Gaucher's disease encapsulated as bone marrow burden score correlate significantly with the number of copies of the N370S allele, which has an ameliorative effect on bone marrow disease. Splenectomy or splenomegaly is associated with greater risk of bone marrow disease. Femoral and lumbar spinal bone marrow burden scores, although only weakly correlated, independently illustrated both the protective role of the N370S allele and the unfavourable implication of splenectomy. This finding suggests that axial and appendicular bone marrow burdens are related but distinct and justifies multiple-compartment evaluation in Gaucher's disease.

The utility of dynamic flexion-extension radiographs in the initial evaluation of the degenerative lumbar spine.

STUDY DESIGN: Retrospective radiographic review. OBJECTIVE: To assess the utility of lateral dynamic flexion-extension radiographs in the initial evaluation of the degenerative lumbar spine. SUMMARY OF BACKGROUND DATA: Most surgeons obtain standing anteroposterior (AP) and lateral radiographs in the initial evaluation of patients presenting with lumbar complaints. The potential role of dynamic films in this population has not been established. METHODS: Of a 390 radiograph series, 342 met inclusion criteria and were reviewed. After assessment of the AP and lateral radiographs, dynamic films were evaluated to determine if additional information was obtained. RESULTS: Only 2 of the 342 radiographic series had new findings seen on dynamic films not appreciated on the AP and lateral films (a L3-L4 anterolisthesis of 3 mm with flexion and a L5-S1 retrolisthesis of 4 mm with extension). Fifteen additional radiographic series were noted to have a change in the amount of anterolisthesis or retrolisthesis on the dynamic films (changes ranged from 2 to 5 mm). CONCLUSION: In the population studied, dynamic radiographs did not significantly alter the initial course of clinical management beyond standing AP and lateral lumbar images.

Imaging-guided bone biopsy for osteomyelitis: are there factors associated with positive or negative cultures?

OBJECTIVE: The objective of our study was to identify the clinical and technical factors associated with positive or negative culture results in histologically positive cases of osteomyelitis obtained from imaging-guided bone biopsies. MATERIALS AND METHODS: A retrospective review was performed of 800 consecutive patients undergoing imaging-guided core bone biopsies at two institutions. Seventy-five biopsies were performed for suspected osteomyelitis and 41 patients had histologically proven osteomyelitis. A chart review was performed to determine whether the following factors affected the culture result: histologic type of osteomyelitis, antibiotic therapy before biopsy, fever (temperature > or = 38.0 degrees C), elevated WBC count (> or = 10 x 10(3) microL), elevated erythrocyte sedimentation rate (ESR) (> or = 10 mm/h), elevated C-reactive protein value (CRP) (> or = 6 mg/L), the size of the biopsy needle, and the amount of purulent fluid obtained at biopsy. RESULTS: Of the 41 cases of osteomyelitis, 14 (34%) had positive cultures. Eighteen (44%) of 41 cases were chronic osteomyelitis. Seventeen (41%) of 41 patients received antibiotics before biopsy, seven (17%) were febrile, five (12%) had an elevated WBC count, 16 (39%) had an elevated ESR, and six (15%) had an elevated CRP value. The biopsy needle size ranged from 11- to 18-gauge. These factors did not have any significant association with positive or negative culture results. Purulent fluid was aspirated in 10 (24%) of the 41 cases. In six (15%) of the cases, > or = 2 mL of purulent fluid was aspirated and five (83%) of the six cases were associated with positive culture (p = 0.02). CONCLUSION: The rate of positive culture results in histologically proven cases of osteomyelitis obtained from imaging-guided bone biopsies is low. Aspirating > or = 2 mL of purulent fluid is associated with a significantly higher rate of positive cultures.