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ABSTRACT |
Monday, May 7, 10:00AM–12:00PM
Abstracts 001-010
Moderator(s): Catherine Roberts and Rick Kijowski
10:00 AM
Keynote Address: MR Evaluation of Bone Marrow in the Pelvis
Catherine Roberts, Mayo Clinic Scottsdale, Scottsdale, AZ
10:20 AM
001. Acute Bone Bruises: Timing of the Appearance of MR Findings in a Swine Model
Blankenbaker D. G.*; De Smet A. A.; Vanderby R.; McCabe R.; Maurer K.; Kijowski R. University of Wisconsin School of Medicine and Public Health, Madison, WI
Address correspondence to D. Blankenbaker (dg.blankenbaker{at}hosp.wisc.edu)
Objective: Occult bone injury may account for post trauma pain and have prognostic implications and sequelae if not treated appropriately. There are no published studies documenting how quickly bone bruises appear on MRI after trauma. The purpose of our study was to determine the MR imaging findings of bone injury following trauma and to document when these MR changes are seen following trauma.
Materials and Methods: We performed serial MRI in 16 knees of 8 swine with 3 nontraumatized knees as controls and 13 knees traumatized by direct patellar impact injuries using a specially designed force calibrated device. All knees were imaged on a 1.5-T scanner using an 8-channel phased array coil with the following sequences: axial and sagittal T1, fat-suppressed fast spin echo T2, and STIR images and coronal STIR images. Scans were performed at 1, 6, 12, and 30 hours following trauma. Two radiologists independently reviewed each MR exam documenting patellar signal intensity changes and then resolved differences by consensus reading.
Results: In the 13 traumatized patellae, low signal intensity on T1 images within the bone marrow was first seen in 8 patellae at 1 hour and 4 patellae at 6 hours. High signal intensity was first seen within the bone marrow on T2 and/or STIR images in 10 patellae at 1 hour and in 2 at 6 hours. One of the 13 traumatized patellae and the 3 nontraumatized patellae never had marrow signal abnormalities. Bone marrow edema was seen on STIR images sooner and more conspicuously than on T2 images.
Conclusion: Bone marrow edema (bone bruises) can be seen as soon as 1hour after trauma but may not be seen until 6 hours after trauma. Both T1 and STIR images are more sensitive than fat suppressed T2 images for the detection of marrow edema.
Clinical Relevance/Application: Bone bruises may be first seen on MRI at variable time intervals. Therefore, MRI done too soon after trauma might be falsely negative for bone injury.
002. MRI Findings in Patients with Fibular Stress Injuries
Sanford M. F.*; Kijowski R.; Choi J.; De Smet A. University of Wisconsin, Madison, WI
Address correspondence to M. Sanford (msanford{at}uwhealth.org)
Objective: The MRI findings in patients with fibular stress injuries have been previously described only in small case reports. This study was performed to summarize the MRI findings in a larger number of patients with fibular stress injuries and to compare the usefulness of MRI and radiographs in the evaluation of these individuals.
Materials and Methods: The study group consisted of 16 consecutive patients with clinically diagnosed fibular stress injuries who were evaluated with MRI. Radiographs were also performed in 13 of the 16 patients. The MRI examinations and radiographs of all patients were retrospectively reviewed by two fellowship-trained musculoskeletal radiologists and one musculoskeletal radiology fellow.
Results: Four patients with clinically diagnosed fibular stress injuries had periosteal reaction on radiographs. The periosteal reaction was discordant in 2 patients and did not correspond to the location of clinical symptoms or MRI abnormalities. The periosteal reaction was concordant in the remaining 2 patients and corresponded to the location of clinical symptoms and MRI abnormalities. One patient with concordant periosteal reaction also had a fracture line through the fibular cortex on radiographs. All 16 patients with clinically diagnosed fibular stress injuries had periosteal edema and bone marrow edema on MRI. The MRI abnormalities were present within the distal fibula in 9 patients, the mid fibula in 4 patients, and the proximal fibula in 3 patients. Periosteal edema was located on the lateral cortex in 9 patients, the posterior cortex in 2 patients, and the anterior cortex in one patient. The periosteal edema was circumferentially distributed along the fibular cortex in 4 patients. Six patients also had abnormal T1 and T2 signal intensity within the fibular cortex. The signal abnormality was location within the lateral cortex in 5 patients and the posterior cortex in one patient. According to the Fredericson MRI classification system, 6 patients had grade II stress injuries, 4 patients had grade III stress injuries, and 6 patients had grade IV stress injuries.
Conclusion: The majority of fibular stress injuries involve the lateral cortex of the distal fibula. Radiographs are insensitive and nonspecific for the detection of fibular stress injuries. MRI can detect fibular stress injuries with much higher sensitivity than radiographs and allows for improved characterization of the exact location and severity of these injuries.
003. Use of Ultrasound in Osteomyelitis and Importance of Power Doppler
Nath A. K.*; Sethu A. S. Khoula Hospital, Muscat, Oman
Address correspondence to A. Nath (akn20j{at}gmail.com)
Objective: To evaluate use of ultrasound and power Doppler in osteomyelitis.
Materials and Methods: Plain radiographs of the affected area and sonography of the affected and the opposite normal area was performed in 200 patients clinically suspected of having osteomyelitis. Sonograms were obtained using multifrequency 7.5- to 11-MHz phased array linear transducer on Power vision 6000 and Aplio 80 Toshiba units. Needle aspiration or surgery was performed to confirm diagnosis. Power Doppler sonographs were also obtained.
Results: 120 of the 200 patients had osteomyelitis, sonographically revealing fluid in contact with the bone with no intervening soft tissue. The fluid proved to be pus.120 osteomyelitis patients had (a) radiograph and ultrasound positive–50 patients (b) radiograph normal initially but ultrasound positive: 70 patients. 50 patients had following findings: 30 patients had soft tissue abscesses, 10 patients had cellulitis and 10 were normal. Limitations of ultrasound in suspected osteomyelitis in remaining 30 patients, will be highlighted, as seen in sickle cell disease (10 patients), septic arthritis (10 patients), epiphyseal ostomyelitis (7 patients) and Brodies abscess (3 patients). Power Doppler helped in showing increased blood supply to infected periosteum, adjacent infected bone and soft tissue.
Conclusion: Ultrasound and power Doppler are useful in 1. Diagnosing, localizing and differentiating osteomyelitis from soft tissue abscesses. 2. Outlining the inflammatory vessels of infected bone. 3. Limitation of ultrasound in osteomyelitis are noted as stated above.
004. Dynamic Ultrasonography in Evaluation of Muscular Trauma
Nath A. K.*; Bouras R. S.; Sethu R. S. Khoula Hospital, Muscat, Oman
Address correspondence to A. Nath (akn20j{at}gmail.com)
Objective: Role of dynamic ultrasonography in muscular trauma
Materials and Methods: Fifty male football players of age group 20 to 30 years, presenting with clinical muscular trauma in thigh and calf region were evaluated in this study. Dynamic ultrasonography of both the affected and contralateral normal part, using 7.5- to 11-MHz phased array linear transducer, with Power Vision 6000 and Aplio 80 Toshiba units, in sagittal, coronal and angulated axis was performed, both without contraction and with contraction of the muscles. Needle aspiration of suspected hematomas was performed for diagnosis and treatment. All muscles tears and hematomas were studied and followed up after 72 hours, until complete healing.
Results: Forty six of the total 50 patients had muscle tears and or hematomas in thigh and calf region. Four patients had no abnormality. Thirty-two patients had clear-cut complete muscle tears appearing as echogenic retracted portions surrounded by hematomas ranging from highly reflective mass to complete echo poor areas on followup. Remaining 14 patients had partial tears, appearing as hypoechoic subtle lesions with relaxed muscle and looking like pseudotumors on contraction because of bunching together of partially broken muscle fibers, which was diagnostic for partial tears. Healed tears appeared as highly reflective scar tissue.
Conclusion: 1: Ultrasonography is very useful in diagnosis, management and followup of muscle tears and hematomas. 2: Dynamic ultrasonography is essential for diagnosis of partial tears.
005. Imaging of Desmoplastic Fibroma
Vidal J. A.1*; Fanburg-Smith J.1; Murphey M. D.1,2 1. Armed Forces Institute of Pathology, Washington, DC; 2. Uniformed Services University of the Health Sciences, Bethesda, MD
Address correspondence to J. Vidal (jorge{at}umkcradres.org)
Objective: To describe the imaging characteristics of desmoplastic fibroma.
Materials and Methods: We retrospectively reviewed 19 cases of pathologically proven desmoplastic fibromas. Radiologic studies reviewed by consensus included: radiographs (n = 18), bone scintigraphy (n = 5), CT (n = 10) and MR imaging (n = 6). Evaluation included patient demographics, clinical history, lesion size, location, pattern of bone lysis, mineralization, soft tissue extension, septations, pathologic fractures, radiotracer uptake and CT/MRI intrinsic characteristics.
Results: Patients included 9 men (50%) and 9 women (50%), with an age average of 31 years. The most common clinical presentation was pain (n = 9) and a palpable mass (n = 4). Location included femur (n = 4), mandible (n = 3), rib (n = 2), humerus (n = 2), fibula (n = 2), pelvis (n = 2), clavicle (n = 1), tibia (n = 1) and radius (n = 1). Size ranged from 2 x 2 cm to 10.5 x 7.5 cm, with an average of 4 x 7.2 cm. Lesions most commonly were centered in the metaphysis (92%) and centrally in the medullary canal (89%). Radiographs revealed geographic lysis (94%) with a narrow zone of transition (50%). Sclerosis was unusual (n = 1). Septations were a prominent feature (83%). Cortical involvement was seen in 50%, pathologic fractures in 22% and periosteal reaction in 11% of cases. Bone scans demonstrated increased tracer uptake in all cases. CT revealed lesions of predominantly similar attenuation to muscle (100%) with septations in 70% of cases. Lesion margins were commonly well defined (70% on CT, 83% on MR). Deep endosteal scalloping (90% on CT, 83% on MR) and cortical destruction (80% on CT, 83% on MR) were common. However, associated soft tissue masses were infrequent (30% on CT, 33% on MR). MR imaging showed all lesions to be predominantly similar in signal intensity to muscle on T1 weighting and low to intermediate signal intensity on T2 weighting (83%). All lesions were heterogeneous on both pulse sequences. Low signal intensity collagenous bands, similar to soft tissue fibromatosis, were seen in the majority of cases (67%). Contrast enhancement was most frequently diffuse (66%).
Conclusion: Desmoplastic fibroma is a rare, benign tumor of bone that typically demonstrates nonspecific imaging appearance. Suggestive features include prominent septations on radiographs and CT, predominant low signal intensity on T2-weighted MR with collagenous bands. Deep endosteal scalloping and cortical destruction often suggest a more aggressive lesion, although soft tissue extension is unusual.
006. Skeletal Muscle Metastases: Imaging and Epidemiology
Lin J. C.*; Haygood T.; Madewell J. E.; Sandler C.; Matamoros A.; Bruzzi J.; Costelloe C. UT MD Anderson Cancer Center, Houston, TX
Address correspondence to J. Lin (Jennifer.C.Lin{at}uth.tmc.edu)
Objective: Skeletal muscle metastases (SMM) have been considered very rare. The purpose of this study was to evaluate the occurrence and characteristics of SMM among patients seen by the authors from March 2003 through May 2006 and compared with those reported in the medical literature.
Materials and Methods: We evaluated cases of SMM collected by the authors between March 2003 and May 2006. We recorded: primary tumor and site, symptoms, age, sex, muscle involved, other metastases, pathological proof, time course, treatment, and outcome. We included cases with a distinct skeletal muscle mass separate from the primary site or other metastases and confirmed the diagnosis either pathologically or by clinical course. CT, MR and/or PET/CT were available for all patients. The same data were gathered from more than 100 published case reports from 1959 to 2006.
Results: Fifty patients (30 men, 20 women) age 20–79, were included. Primary tumors were: melanoma (9), lung (8), kidney (8), breast (6), esophageal (3), sarcoma (3), and others (13). Presentations included: asymptomatic (22), pain (17), mass (8), limited range of motion (1), unknown (2). Of the asymptomatic patients, 13 were detected by CT, 4 by MRI, and 5 by PET/CT. Metastatic sites were the trunk muscles (24), gluteal (8), upper (10), and lower (8) limbs. Forty-eight had other sites of metastases at the time of SMM diagnosis. Only 2 patients had isolated SMM. Proof was by biopsy (11), surgical excision (3), autopsy (1), biopsy of an alternate lesion combined with imaging findings (22). In 7 cases, determination was by clinical evaluation without biopsy. Time intervals between discovery of the primary tumor to the skeletal muscle metastasis included: synchronous (9), within 6 months (11), 6 months to 1 year (11), 1–5 years (11), and more than 5 years (6). In 2 patients, the metastasis was discovered before the primary tumor. Twenty-six were treated with chemotherapy alone. Twenty-two received both chemotherapy and radiation. One patient was treated with radiation only, and one patient was sent to hospice. Currently, 20 are alive, 23 have died, 6 have continued treatment elsewhere, and 1 went to hospice. The average survival times of living and deceased patients are 7 and 8.6 months, respectively.
Conclusion: SMM are more common than published reports would suggest. SMM may first be evident on imaging studies, and radiologists need to be alert for them when interpreting CT, MRI or PET as patient management may be altered.
007. FDG-Avid Nonmalignant Conditions in the Musculoskeletal System
Patel K.*; Gong R.; Maragh M.; Seo G.; Monu J. U. University of Rochester School of Medicine and Dentistry, Rochester, NY
Address correspondence to K. Patel (kalpesh_patel{at}urmc.rochester.edu)
Objective: The role of PET/CT in tumor imaging and staging using 18-fluorodeoxyglucose (FDG) is well established. However, increased radio-tracer uptake may occur in non-malignant conditions and result in incorrect staging of neoplastic process. These pitfalls in musculoskeletal imaging are not well recognized or documented. This presentation documents our experience with some such pitfalls in the musculoskeletal system.
Materials and Methods: We reviewed our database over a 26-month period (June 2004--August 2006) for patients who had PET/CT imaging for tumor work up and who had positive findings in the musculoskeletal system. The PET/CT studies were read by consensus by experienced radiologists who consulted musculoskeletal radiologists when necessary. Each examination was evaluated for the presence or absence of increased uptake on the PET/CT. Specific uptake values (SUV's) were noted as supporting data. The patients' clinical records were reviewed and correlated with other studies including imaging guided or excisional biopsy.
Results: 174 cases that had abnormalities in the musculoskeletal system out of 1783 patients seen in this period. Of the 174 cases, 71 cases had increased uptake in the bone and 20 had increased soft tissue uptake related to the patients' primary condition. 76 cases were due to degenerative joint disease. In the soft tissues, two cases of abnormal intra-articular uptake were surgically proved pigmented villonodular synovitis. Extra-articular soft tissue uptake in 13 cases was diagnosed as bursitis, one case was due to soft tissue hemangioma in the thigh and another case was calcified tendonitis.
Conclusion: Practitioners need to be aware of those benign entities that are FDG avid on PET/CT scan and may confound musculoskeletal tumor imaging. Tissue diagnosis should be obtained in the setting of unusual soft tissue radiotracer uptake.
008. Whole-body MRI of Multiple Myeloma: Comparison of Different MRI Sequences in Assessment of Different Growth Patterns
Weininger M.*; Lauterbach B.; Kenn W.; Hahn D.; Beissert M. University Hospital of Wuerzburg, Wuerzburg, Germany
Address correspondence to M. Weininger (weininger{at}roentgen.uni-wuerzburg.de)
Objective: To determinate sensitivity, specificity and inter-observer variability of different whole-body MRI sequences in patients with multiple myeloma.
Materials and Methods: Whole-body MRI (1.5-T, Magnetom Avanto, Siemens, Germany) was performed on 23 patients (13 men, 10 women; mean age 63 ± 12 years) with histologically proven multiple myeloma and classified according to infiltration (low-grade, n = 7; intermediate-grade, n = 7; high-grade 3, n = 9) and to the staging system of Durie and Salmon (stage 1, n = 12; stage 2, n = 4; stage 3, n = 7). The control group consisted of 33 individuals not suffering from malignancy (25 men, 11 women; mean age 57 ± 13 years). Two experienced radiologists in a blinded fashion evaluated the following wholebody MRI sequences: Pre-contrast T1-TSE (T1), T2-TIRM (T2), and the combination of both sequences, including postcontrast T1-TSE with fat saturation (T1/T2 PC). The observers had to determine the growth pattern (focal and/or diffuse) and the MRI sequence with the highest confidence level.
Results: Visual detection of multiple myeloma was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1/T2 PC, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1/T2 PC, 0.55. Sensitivity improved depending on infiltration grade (T1: 1 = 60%; 2 = 36%; 3 = 83%; T2: 1 = 70%; 2 = 71%; 3 = 89%; T1/T2 PC: 1 = 50%; 2 = 50%; 3 = 89%) and clinical stage (T1: 1 = 58%; 2 = 63%; 3 = 79%; T2: 1 = 58%; 2 = 88%; 3 = 100%; T1/T2 PC: 1 = 50%; 2 = 63%; 3 = 100%). Best sensitivity with 76% was achieved using T2-TIRM sequences, which also received the highest confidence level (k = 0.62).
Conclusion: Visual detection of multiple myeloma with whole-body MRI varies depending on the infiltration grade and the clinical stage. T2-TIRM sequences achieved the highest sensitivity and the highest confidence level in detection of multiple myeloma.
009. Correlation of Red Marrow Volume Determined by Whole Body MRI and Subsequent Comparison with Bone Density and Serum Cytokine Levels
O'Brien J.1*; Shelly M.; Kerr J.1; McMahon P.1; Cotter E.; Doran P.2; Eustace S.1 1. Cappagh National Orthopaedic Hospital, Dublin, Ireland; 2. Dublin Molecular Medicine Centre, Genome Resource Unit, Dublin, Ireland
Address correspondence to J. O'Brien (Juliemarobrien{at}yahoo.com)
Objective: To evaluate the relationship between red marrow volume determined by whole-body MRI and bone density. In addition we aim to evaluate the relationship between these results and serum cytokines levels.
Materials and Methods: 124 participants were included in this study. In each case, bone density was recorded by conventional DEXA scanning. Wholebody MRI was performed on a 1.5-T scanner with an extended table-top for automated movements. Each patient underwent sagittal and coronal T1, and coronal STIR sequences to determine red marrow patterns and volume. In addition serum was yielded to determine cytokine levels using conventional ELIZA techniques. The cytokines, chosen due to of their action on the osteoblast/osteoclast cycle and bone marrow included: leptin, bone morphogenic protein (BMP), TNF alpha and TGF beta. Comparison was then made between these cytokines and the corresponding bone density and marrow volume.
Results: Total body red marrow quantities, as determined by whole body MRI, appear to correlate with recorded levels of bone density. Similarly there was also a correlation between this relationship and measured serum leptin and BMP levels.
Conclusion: The results of this study suggest a direct relationship between the total body red marrow volume, and the bone density. This suggests that red marrow provides a milieu for the maintenance for healthy bone, and therefore appears to be a significant contributor to the maintenance of bone health. The utility of bone turnover markers as a complement to bone mineral density (BMD) measurements is evolving because bone density measurements only provide information about the current skeletal mass, but do not provide information about the metabolic activity, and may be a useful adjunct to BMD measurement, for prediction of patients at higher risk of reduced bone density.
010. MRI Evaluation of Idiopathic Inflammatory Myopathy: Improved Fat-Muscle Separation Using A Modified Dual Flip Angle Dixon Technique
Gai N.*; Yao L. National Institutes of Health, Bethesda, MD
Address correspondence to N. Gai (gaind{at}cc.nih.gov)
Objective: Robust fat-water separation (FWS) continues to be challenging in clinical MR applications that survey large body regions. FWS can facilitate MRI determination of tissue fat fraction. Muscle fat fractions may serve as a noninvasive quantitative measure of disease damage in idiopathic inflammatory myopathy (IIM). A dual flip angle Dixon technique (DFAD) was recently described (Hussain et al., Radiology, Dec. 2005) which obviates the processing of phase data. In this study, we apply a modified version of the DFAD technique to the measurement of fat fractions in the thigh muscles of patients with IIM.
Materials and Methods: Eleven patients underwent MRI evaluation for suspected IIM at 1.5 T. A dual echo FGRE sequence (TE1/TE2/TR = 2.1/4.4/200 ms) was acquired at two different flip angles (20° and 90°). The original DFAD method classifies pixels as predominantly fat or water-containing based on differences in T2* corrected fat fraction at the two flip angles; this tends to fail in homogeneous fat or water regions. Our modification classifies pixels based on a threshold applied to the sum of T2* corrected in-phase and out-of-phase images. FWS was also done using a region growing, phase correction based method applied to the large flip angle FGRE acquisition (adapted from J. Ma, Mag Reson Med, 2004). FWS in the thigh was scored by an experienced musculoskeletal radiologist on a scale of 0 to 4.
Results: The average scores for the phase correction technique, the original DFAD algorithm, and the modified DFAD technique were 1.55, 1.91 and 1.36, respectively. While the differences were not statistically significant (Friedman test p-value = 0.37), the modified DFAD technique scored higher than the original DFAD method in 7 of 11 patients. Misclassifications with the modified DFAD method tended to be small and scattered; with the original DFAD method they tended to be larger and irregular; with phase correction they tended to be regional and smooth.
Conclusion: Robust FWS is still problematic in large field of view applications at 1.5 T. A recently reported dual flip angle Dixon technique is promising and simple to implement. Modifying a key step in the postprocessing algorithm is necessary for more effective application of this technique to the MRI survey of the thigh muscles.
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