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ABSTRACT |
Monday, May 7, 1:30 PM–3:30 PM
Abstracts 046-055
Moderator(s): Adam Zoga and Josh Polster
1:30 PM
Keynote Address: Imaging Groin Pain in the Young Adult: Confounders from the Hip to the Symphysis
Adam Zoga, Thomas Jefferson University, Philadelphia, PA
1:50 PM
046. MR Imaging of the Rectus Abdominus/Adductor Aponeurosis: Findings in the `Sports Hernia'
Kavanagh E. C.4*; Zoga A. C.3; Omar I.2; Koulouris G.3; Gopez A.3; Bergin D.3; Morrison w. B.3; Meyers W. C.1 1. Drexel University Medical Center, Philadelphia, PA; 2. Northwestern University, Chicago, IL; 3. Thomas Jefferson University Hospital, Philadelphia, PA; 4. University of Pittsburgh Medical Center, Pittsburgh, PA
Address correspondence to E. Kavanagh (eoinkav{at}yahoo.com)
Objective: Terms including athletic pubalgia and sports hernia are frequently used, poorly understood, and incompletely described in the imaging literature. We sought to describe the MRI findings in a patient population with these clinical diagnoses and define the term `sports hernia' based upon imaging and surgical findings.
Materials and Methods: 62 (M:F = 51:11, mean age = 27.6) patients referred from a single surgical subspecialist for clinical athletic pubalgia were imaged at 1.5 T utilizing a pubalgia protocol optimized for pelvic floor and pubic symphysis pathology. MRIs were reviewed by 3 musculoskeletal radiologists in consensus and pathology involving the pubic symphysis, rectus abdominus, hip adductors, pelvic floor, abdominal wall and peritoneum were recorded. MRI findings were correlated with clinical findings in all patients and with surgical findings when applicable.
Results: The most frequent location for pathology on MRI was at the anterior/inferior pubis, just lateral to the symphysis where the lateral head rectus abdominus inserts and the common adductor tendon originates (rectus/adductor aponeurosis). 36/62 patients had pathology localized here, including tendinous disruption, tendinosis, periosteal avulsion, and marrow edema. Patients placed in this group correlated strongly with a clinical diagnosis of `sports hernia,' and the majority (28) were treated with surgical pelvic floor reconstruction. At surgery, rectus insertional pathology was seen in all 28 patients (MRI specificity = 100%). 11/62 patients had isolated hip adductor pathology on MRI. Only 2/11 went to surgery, both with true-positive adductor tendinosis and 1 with false-negative rectus abdominus injury. One patient had a direct inguinal hernia on MRI which was repaired at surgery. One patient had a thigh mass which was resected and came back synovial cell sarcoma. Other pathologies seen on MRI, but without surgical verification, included osteitis pubis (5) and stress fracture (2). Only 6/62 patients had no MRI findings to explain the pubalgia.
Conclusion: MRI is an essential tool in the work-up of groin pain and athletic pubalgia. Specific and reproducible patterns of pathology on MRI should be recognized and reported. The imager must be familiar with pathologies including the rectus/adductor aponeurosis injury (sports hernia), adductor syndrome, and osteitis pubis. The `sports hernia' actually reflects a breech in the pelvic floor involving the anterior/inferior pubis, the lateral head of the rectus abdominus, and the hip adductor origins.
047. Incidental Findings on Routine Hip MRI: Frequency and Follow-Up
Ruzbarsky A. L.2*; Morrison W. B.2; Bergin D.2; Gopez A.2; Zoga A.2; Roberts C. C.1 1. Mayo Clinic, Scottsdale, AZ; 2. Thomas Jefferson University Hospital, Philadelphia, PA
Address correspondence to A. Ruzbarsky (Allison.Ruzbarsky{at}Jefferson.edu)
Objective: On routine hip MRI the pelvis and abdominal organs are often visible within the field of view or on the scout localizer. We sought to determine the frequency and impact of reporting of incidental (non-musculoskeletal) findings on these exams.
Materials and Methods: Reports of 1377 consecutive hip MRI exams from 1999 to 2005 were reviewed. Incidental findings (non-musculoskeletal) were recorded including type of finding, organ involved, and recommendations for follow-up imaging, if any. Results of these follow-up exams were reviewed when available.
Results: 14.5% (200 of 1377) reports mentioned incidental findings. Most common findings involved uterine fibroids/adenomyosis (72; 36%); adnexal cysts or masses (59, 30%); enlarged prostate (15, 8%); renal cystic lesions (9, 5%); enlarged inguinal nodes (8, 4%); scrotal hydrocele (7, 4%); thickened endometrial canal (7, 4%); diverticula (6, 3%); bladder wall thickening (6, 3%), and inguinal hernia (6, 3%). There were a variety of other findings. 49% of these reports (98/200) recommended follow-up imaging, most commonly ultrasound (71, 72%) followed by MRI (17, 17%); nonspecified pelvic imaging (6, 6%); CT (1, 1%); radiography (1, 1%); and cystography (1, 1%). Physical exam was recommended in 12 (12%). Follow-up imaging was available for 44 (45%). Significant findings included: bladder carcinoma, endometrial carcinoma, tumor of the appendix, and hydronephrosis. Further follow-up imaging was recommended in 5 (11%). A cost analysis will be performed.
Conclusion: A relatively large proportion of routine hip MRI exams (14.5%) report incidental findings outside the musculoskeletal system. This is because imaging generally includes much of the pelvic and abdominal organs. Usually imaging is limited with regard to a specific diagnosis, so additional imaging tests are ordered, which can increase cost of medical care but occasionally detects important pathology.
048. Correlation of MRI Findings with Clinical Findings of Trochanteric Pain Syndrome
Ullrick S. R.*; Blankenbaker D. G.; Davis K. W.; De Smet A. A. University of Wisconsin Hospital and Clinics, Madison, WI
Address correspondence to S. Ullrick (SUllrick{at}uwhealth.org)
Objective: Greater trochanter pain syndrome, a common cause of hip pain, is reported to cause peritrochanteric fluid and abductor tendon signal abnormality at MRI. However, we have often noted peritrochanteric high T2 signal in patients without trochanteric symptoms. The purpose of this study was to determine whether the MR findings of peritrochanteric fluid or hip abductor tendon pathology correlate with trochanteric pain.
Materials and Methods: We retrospectively reviewed 131 consecutive MR examinations of the pelvis (256 hips) for T2 peritrochanteric fluid and abductor tendon abnormalities without knowledge of the clinical symptoms. Any T2 peritrochanteric fluid was characterized by size as tiny, small, medium, or large; by morphology as feathery, crescentic, or round; and by location as bursal or intratendinous. Then, the MRI findings were compared to the clinical symptoms and evaluated for significant differences in positive MR findings for patients with and without trochanteric pain using chi-square or Fisher's exact test. Significance was assigned as p < 0.05.
Results: Clinical symptoms of trochanteric pain syndrome were present in only 16 of the 256 hips. All 16 hips with trochanteric pain and 212 (88%) of 240 without trochanteric pain had peritrochanteric abnormalities (p = 0.15). 81% of the 16 symptomatic hips had subgluteus bursal fluid, gluteus medius and/or minimus tendinopathy, and trochanter bursal fluid while 47% of the hips without trochanteric symptoms had these 3 findings (p = 0.007). 88% of hips with trochanteric symptoms had gluteus tendinopathy while 50% of those without symptoms had such findings (p = 0.004). There was no statistically significant difference between hips with or without trochanteric symptoms and the presence of peritrochanteric bursal fluid, size or shape of the fluid and the presence of gluteus medius or minimus tears.
Conclusion: Trochanteric pain syndrome is significantly associated with hip abductor tendinopathy and with a combination of subgluteal and trochanteric bursal fluid and abductor tendinopathy. Although the absence of peritrochanteric MR abnormalities makes trochanteric pain syndrome unlikely, detection of these abnormalities on MRI has a poor positive predictive value since these findings are present in a high percentage of patients without trochanteric pain.
049. Iliopsoas Tendon Injuries: MRI Findings
Bui K. L.*; Sundaram M.; Recht M.; Subhas N.; Ilaslan H. Cleveland Clinic, Cleveland, OH
Address correspondence to K. Bui (buik{at}ccf.org)
Objective: Iliopsoas tendon pathology is an uncommon cause of hip pain and there has been little description of the MRI findings of iliopsoas tendon injuries. The purpose of this paper is to describe the spectrum of MRI findings of patients with iliopsoas tendon injuries and review associated clinical findings.
Materials and Methods: A retrospective computerized search of the radiology database between 1/1/02–4/28/06 was performed to find MRI examinations describing iliopsoas tendon injuries. The MRI examinations were re-reviewed. Iliopsoas injuries were graded as: tendinosis (intermediate/increased tendon signal on STIR and T2-weighted images without interruption of the fibers), partial tears (partial interruption of the tendon fibers), and complete tears (complete interruption of the tendon fibers). Available medical records were reviewed.
Results: There were 32 patients with ages ranging from 7 to 95 years old (average age 54). Ten patients had iliopsoas tendinosis (one patient had bilateral involvement), 13 patients had partial iliopsoas tendon tears and 9 patients had complete iliopsoas tendon tears. There were 18 women and 14 men. The right iliopsoas tendon was involved in 19 cases and the left in 12 cases and one patient had bilateral involvement. There were no patients with lesser trochanteric bony avulsion. Eighteen of 32 patients had a history of trauma. In the younger age group, sports-related trauma was frequently seen. However, in elderly patients, falls were a common cause of injury. All patients were treated conservatively.
Conclusion: Iliopsoas tendon injuries may range from tendinosis to complete avulsions in a broad age group. Partial tendon tears were the most common pattern. None of the patients in our study had lesser trochanteric bony avulsion. The athletic activities resulting in iliopsoas tendon injuries will be discussed.
050. Do Radiographs Correctly Predict Cam Femoroacetabular Impingement?
Davis K. W.*; Blankenbaker D. G.; Cabay M. E. University of Wisconsin School of Medicine and Public Health, Madison, WI
Address correspondence to K. Davis (kdavis{at}uwhealth.org)
Objective: The MR arthrographic alpha angle has been validated as a tool to diagnose cam femoroacetabular impingement (FAI). This angle is measured on oblique axial images of an MR arthrogram of the hip. However, some morphologic features of the femoral neck on radiographs are thought to reflect FAI. If one could validate radiographic indicators of FAI, radiographs could become a helpful screening tool. The purpose of this study is to determine the accuracy of hip radiographs for predicting cam femoroacetabular impingement (FAI), as determined by the MR arthrogram alpha angle.
Materials and Methods: For a previous study, 117 MR arthrograms of the hip had been retrieved from the PACS archive and the FAI alpha angle measured by two musculoskeletal radiologists and one radiology resident by consensus. From this cohort, 69 subjects had radiographs of the same hip. For the current study, these radiographs were assessed by two musculoskeletal radiologists for morphologic appearance of cam femoroacetabular impingement. Criteria for FAI included the presence of a bump or convexity at the anterolateral junction of the femoral head and neck; a flat or concave contour at this junction was called normal. Observations were recorded for the radiographs available, including anteroposterior (AP), cross-table lateral (XTL), and frog-lateral (frog).
Results: Of the 69 subjects, 24 (35%) had FAI as determined by an alpha angle of 55 degrees or more. All 69 subjects had AP views. If only AP views were used, sensitivity of a bump for abnormal alpha angle was 25% and specificity was 100%. 29 subjects had a XTL view. Used alone, a bump on XTL had sensitivity of 57% and specificity of 100%. 45 subjects had a frog view, which, when used alone, generated sensitivity of 43% and specificity of 97%. If all views for subjects were evaluated, with a bump on any view considered as positive, sensitivity was 42% and specificity 98%. For the 12 subjects with all 3 views, sensitivity was 50% and specificity 100%.
Conclusion: The presence of a bump at the anterolateral femoral head-neck junction is a specific but not sensitive indicator of FAI, as determined by the alpha angle. The femoral neck bump is a marker for cam FAI and should be sought and reported on radiographs.
051. The Femoroacetabular Impingement Alpha Angle: How Reliable Is It?
Cabay M. E.*; Davis K. W.; Blankenbaker D. G.; Mukherjee R. University of Wisconsin School of Medicine and Public Health, Madison, WI
Address correspondence to M. Cabay (me.cabay{at}hosp.wisc.edu)
Objective: Femoroacetabular impingement (FAI) is increasingly cited as a potential cause of early osteoarthrosis of the hip. In some centers, younger adults with hip pain and FAI undergo surgical procedures to correct the impingement anatomy and repair or debride labral tears and cartilage damage that already exist. Several radiologic measurements and features have been proposed as diagnostic of cam FAI, one of the two types of FAI. The most popular measurement is the alpha angle, measured on oblique axial images from MR arthrograms. We have noticed that the alpha angle, although validated in one surgical study, is difficult to reproduce. The purpose of this study was to determine if alpha angle measurements are reproducible.
Materials and Methods: Subjects included 50 consecutive patients who underwent direct MR arthrography of the hip. Two musculoskeletal radiologists and one radiology resident independently measured the FAI alpha angle on a midslice image from the oblique axial sequence. Measurements were performed using tools available on the standard PACS monitors at the authors' institution. More than one month later, each reader independently measured the FAI alpha angle on the same 50 subjects. The intra- and inter-rater reliability for the continuous measurements were obtained by calculating the Shrout-Fliess reliability coefficient based on the intra-class correlations obtained from fitting a generalized linear model on the alpha angle adjusting for readers and patients. For the categorized data, Kendall's coefficient of concordance was calculated.
Results: Inter-rater correlation for continuous angle measurements was 0.44329 (moderate). Intra-rater correlations for the 3 readers varied from 0.09 (poor) to 0.39 (fair). When categorizing the measurements into normal or abnormal, the inter-rater coefficient of concordance was improved at 0.59893, but still moderate: i.e., when comparing whether alpha measurements were normal or abnormal, the graders changed from normal to abnormal 6–14 times (out of 50) when compared to themselves, and 8–17 times when compared to each other.
Conclusion: The primary attraction of the alpha angle for diagnosing cam FAI is its ease of use. However, it is, at best, a moderately reliable measurement. Other radiologic measurements and findings should be sought that are accurate and reliable at diagnosing FAI, to supplement clinical measures already in use.
052. Radiologic Findings of Femoroacetabular Impingement Syndrome: Correlation with Surgical Findings
Lee C.2*; Hong S.2; Shon W.1; Han S.1; Park C.2 1. Department of Orthopedic Surgery, Guro Hospital, Korea University College of Medicine, Seoul, South Korea; 2. Department of Radiology, Guro Hospital, Korea University College of Medicine, Seoul, South Korea
Address correspondence to C. Lee (lemoniatree{at}korea.ac.kr)
Objective: To retrospective analyze the radiographic and MR imaging findings of femoroacetabular impingement (FAI) correlating with clinical and surgical findings.
Materials and Methods: From January 2005 to July 2006, 11 patients
with clinically suggested FAI underwent plain hip radiographs and MR
arthrography. Of the patients, we retrospectively analyzed 8 patients who
underwent operation for FAI. There were 7 men and 1 woman, with a mean age
28.6 years (range 19
46 years). All 8 patients showed hip pain, 4 patients
showed characteristic hip pain during squatting position, and 7 patients
showed positive impingement test. We analyzed bump appearance, acetabular
retroversion, acetabular protrusion, osteoarthritis (K-L score) in plain hip
radiographs. In MR arthrography, we analyzed alpha angle, anterior or
anterolateral labral tear, cartilage abnormality (Outerbridge grade),
herniation pit, paralabral cyst, subchondral cyst, and subchondral marrow
edema. We correlated the radiologic findings with operative findings after
review of medical records.
Results: In plain radiographs, all 8 patients showed bump
appearance and osteoarthritis (K-L score IIIV), and 5 (62.5%) patients
showed acetabular retroversion. In MR arthrography, anterior or anterolateral
acetabular labral tear and mild cartilage abnormality (grade I, II) were seen
in all 8 patients (100%), increased alpha angle (greater than 50 degrees) was
seen in 6 cases (75%). There was no acetabular protrusion, subchondral cyst or
marrow edema, paralabral cyst, herniation pit. On operation, all 8 patients
were confirmed with the anterolateral impingement of hip by impingement test.
Anterior or anterolateral labral tear, bump appearance, and mild cartilage
abnormality were seen in 8 patients during operation. Bumpectomy, labral
repair, and acetabular trimming were performed in all patients. We divided the
type of FAI as 2 cam type, 5 mixed type, and 1 undetermined type according to
the radiologic and operative findings.
Conclusion: The reliable radiologic findings of FAI syndrome were acetabular retroversion, bump appearance, and early osteoarthritis in plain radiographs, anterior or anterolateral labral tear, cartilage abnormality, and increased alpha angle in hip MR arthrography. The mixed cam and pincer type was the main prevalent type.
053. Correlation of MR Imaging and Provocative Discography in Patients with Clinically Suspicious Discogenic Low Back Pain: A Combination Analysis of the High Intensity Zone and Disc Contour
Kang C.1*; Kim J.1; Chung K.1; Kim B.2; Hong S.3 1. Anam Hospital, Korea University College of Medicine, Seoul, South Korea; 2. Ansan Hospital, Korea University College of Medicine, Ansan-Si, South Korea; 3. Guro Hospital, Korea University College of Medicine, Seoul, South Korea
Address correspondence to C. Kang (mallecot{at}hanmail.net)
Objective: To correlate MR findings with pain response at provocative discography in patients with clinically suspicious discogenic low back pain, with emphasis on the combination analysis of the high intensity zone (HIZ) and disc contour.
Materials and Methods: Thirty-seven patients aged 21–86 years with axial low back pain and with or without radicular leg pain underwent prospective clinical examination and MR imaging. Subsequently, patients underwent lumbar discography with a pain provocation test (107 discs). MR images were evaluated for HIZ with disc contour (protruding or not), disc degeneration, disc herniation, endplate abnormalities and facet joint osteoarthritis. During discography concordant pain was regarded as positive, whereas discordant pain and no pain were regarded as negative. The prevalence of all MR abnormalities was calculated, and the data were compared with pain response, as evidenced at discography.
Results: Concordant pain was observed in 24 patients (65%) and 29 disc levels (27%). The HIZ with protruding contour on MRI correlated significantly with the pain provocation (sensitivity, 31%; specificity, 97%; PPV, 82%). The presence of an HIZ without protruding contour was not associated with reproduction of pain. Disc herniation, disc degeneration, endplate abnormalities and facet joint osteoarthritis were not helpful in the identification of symptomatic disc derangement.
Conclusion: HIZ with protruding contour on MRI appear to be useful in the prediction of painful disc derangement in patients with discogenic low back pain.
054. Predictive Value of MRI Findings for Temporomandibular Joint Disc Displacement
Maizlin Z. V.*; Harrison P. B.; Vos P. M.; Clement J. Department of Radiology St. Paul's Hospital, Vancouver, Canada
Address correspondence to Z. Maizlin (zeev25{at}yahoo.com)
Objective: To determine the diagnostic and prognostic value of the location of interiorly displaced temporomandibular joint (TMJ) meniscus on MRI. Since an anterior displacement of the TMJ meniscus without reduction requires surgical treatment, the predictive value of MRI is highly important.
Materials and Methods: 144 TMIs were imaged in 72 patients between May 1999 and September 2006. MRI examinations were performed on 1.5-T system in the closed and open mouth positions. The morphology and position of the disc in mouth closed position was recorded. The normal position of the meniscus was diagnosed when the posterior band was located at 12 o'clock position in relation to the condyle. Joints with an internal derangement of anteriorly displaced meniscus type were divided into groups based on the location of the posterior band of the meniscus in relation to the condyle. In cases of anterior displacement of the meniscus, presence or absence of disc reduction with opening of the mouth was determined. Correlation of the displaced disc position and reduction was performed.
Results: In 40% (58/144) of joints an internal derangement of anteriorly displaced meniscus type was diagnosed. In 79.3% (46/58) of these joints the posterior band was located in the 9–11 o'clock region. In another group there were 12 joints with the posterior band located in the 8–9 o'clock region or was displaced even further. Lack of disc reduction in open mouth position was significantly higher in the discs of the second group.
Conclusion: The degree of the displacement may be defined by the location of the posterior band in relation to the condyle. Internal derangement of an anteriorly displaced meniscus type can result in disruption of the posterior attachment tissues – the bilaminar zone. The degree of the displacement correlates well with the lack of reduction of the articular disc in mouth open position.
055. Radiofrequency Neurotomy of Medial Branches for Chronic Zygapophyseal Joint Pain in Radiological Settings
Maizlin Z. V.*; Clement J.; Harrison P. B. Department of Radiology St. Paul's Hospital, Vancouver, Canada
Address correspondence to Z. Maizlin (zeev25{at}yahoo.com)
Objective: To determine the outcome of radiofrequency (RF) neurotomy performed in a radiology setting and to compare the results with results published in the anesthesiological and neurosurgical literature.
Materials and Methods: Eighty-six RF neurotomies were performed by a radiologist between January 2005 and September 2006. Only patients whose primary source of pain was confirmed by comparative diagnostic middle branch blocks of the zygapophyseal joints, were selected for RF neurotomy. The procedures were performed in an aseptic manner and under fluoroscopic guidance. Prior to neurotomy, sensory and motor tests ensured the proper placement of the electrode. The results were evaluated based on visual–analogue scale diaries completed by the patient following the procedure.
Results: The average number of nerve branches treated with RF neurotomy was 6 per patient. Postoperatively, pain relief was complete in 69 (80%) of patients. An improvement in pain levels was reported in 12 (14%) patients and the remaining did not record any change in pain levels after the procedure. Eighty three percent of patients recorded increased physical activity presumably due to the decrease of pain. Outcome was not significantly influenced either by the side or level of the neurotomy. The results are comparable with those published in the anesthesiological and neurosurgical literature.
Conclusion: RF neurotomy is intended to ablate the sensory fibers of the medial branch of the posterior primary ramus thus rendering the facet joint asensate. RF neurotomy of the medial branch is currently the only proven way to treat patients with chronic zygapophyseal joint pain. Thorough knowledge of roentgen anatomy and experience in interventional radiology allow the radiologist to perform RF neurotomy of the medial branch with clinically satisfactory results.
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