MRI for Differentiating Ganglion and Synovitis in the Chronic Painful Wrist

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1 nderson et al. MRI in the hronic Painful Wrist Musculoskeletal Imaging linical Observations M E D E N T U R I L I M G I N G JR 2006; 186: X/06/ merican Roentgen Ray Society Y O Suzanne E. nderson 1 Lynne S. Steinbach 2 Edouard Stauffer 3 Esther Voegelin 4 F Keywords: ganglion, hand, MRI, musculoskeletal imaging, synovitis, wrist DOI: /JR Presented at the 2003 annual meeting of the Radiological Society of North merica, hicago, IL. Received December 10, 2004; accepted after revision February 2, Department of Diagnostic, Interventional, and Pediatric Radiology, University Hospital of ern, Inselspital, Freiburgstrasse, H-3010 ern, Switzerland. ddress correspondence to S. E. nderson (suzanne.anderson@insel.ch). 2 Department of Radiology, University of alifornia, San Francisco, San Francisco,. 3 Department of Pathology, University Hospital of ern, Inselspital, ern, Switzerland. 4 Department of Orthopedic, Plastic, and Reconstructive Surgery, Division of Hand Surgery, University Hospital of ern, Intesspital, ern, Switzerland. MRI for Differentiating Ganglion and Synovitis in the hronic Painful Wrist OJETIVE. The purpose of our study was to determine if preoperative MRI can differentiate between occult ganglion and synovitis in the chronic painful wrist. ONLUSION. MRI is accurate in preoperatively distinguishing between ganglion and synovitis in the setting of chronic dorsal wrist pain. Four main criteria were useful: margin, shape, internal structure, and enhancement after administration of contrast material, with shape and internal structure being most helpful. hronic wrist pain is a therapeutic challenge for hand surgeons. Dorsally located wrist pain over the scapholunate ligament is a common problem; however, there is little information available in the radiologic literature regarding diagnosis. Literature on wrist pain concentrates largely on rheumatoid arthritis. mong the known etiologies of chronic dorsal wrist pain are dorsal occult ganglion cysts, posterior interosseous neuroma or neuropathy, dorsal impaction syndrome, avascular necrosis of the lunate or scaphoid, ligamentous tears, fractures, tumors, inflammatory arthropathies, and extensor tenosynovitis [1, 2]. Occult wrist ganglions are small, benign cystic lesions usually located at the dorsal scapholunate interval but they may occur in the radiopalmar or radioulnar aspects in the wrist. They may be the result of a chronic irritation to the scapholunate or other intercarpal ligaments. When there is no swelling in combination with pain and there is no underlying carpal instability, these lesions are not detectable by physical and routine radiographic examinations. Therapy for recalcitrant chronic wrist pain that has not responded to conservative treatment is surgical exploration. Unfortunately, some of these surgical explorations yield no specific diagnosis because cystic lesions may vary in size and have a more or less central mucinous content. While chronic tenosynovitis of the extensor tendons can be easily distinguished from a dorsal (not occult) ganglion, swelling and puckering seen with digital extension are clinically not present in occult synovitis. Tenosynovitis refers to inflammation of the synovial lining of a tendon sheath or a joint and is associated with rheumatoid arthritis. Other inflammatory-type etiologies include deposition diseases such as amyloidosis, crystalline tendinopathy such as calcific tenosynovitis or gout, and septic tenosynovitis [3]. More common is the reactive tenosynovitis occurring about the narrow fibroosseous canals that provide fulcrums for acute angulation of wrist tendons. Reactive occult tenosynovitis of the wrist extensors and flexors is not rare. The surgical approach for this condition varies from that for occult ganglion cysts. The use of MRI in the diagnosis of dorsal occult ganglion cysts has been previously reported [4, 5]. However, the question remains whether MRI can differentiate between ganglion and other perisynovial fibrous tissue that is a noninflammatory synovitis. This retrospective study assesses the efficacy of high-resolution MRI in patients with recalcitrant dorsal wrist pain who have an otherwise negative workup. ecause no MRI criteria were available in the literature allowing clear distinction between occult ganglion and synovitis, review of a consecutive patient cohort was performed and these findings are presented. MRI criteria were used to define an MRI diagnosis that was subsequently correlated with intraoperative findings and histology. In addition, MRI features were analyzed to differentiate between ganglion and synovitis. 812 JR:186, March 2006

2 MRI in the hronic Painful Wrist Materials and Methods Patients Eighty consecutive patients underwent MRI for chronic wrist pain between 1998 and Patients included in the study were those with chronic dorsal wrist pain of longer than 3 months duration who subsequently had surgery and either surgical or histopathologic correlation. The pain time duration was arbitrarily chosen because there is no current definition in the hand surgery literature and no data are available. Patients included in the study had no clinical evidence of swelling. Patients with triangular fibrocartilage or full-thickness scapholunate ligament tears, traumatic or posttraumatic injuries, previous surgery to the wrist, vascular abnormalities of carpal bones, or a rheumatologic inflammatory joint disease such as rheumatoid arthritis were excluded from the study. The patient list was generated through the database of the hand surgery department at a tertiary referral center. Thirty-four patients fulfilled the inclusion criteria. Forty-six patients were treated conservatively and are not included in the study because no gold standard is available. Radiographs were reviewed for the presence of soft-tissue swelling or calcification and for any underlying bone or joint disease and had to be normal for the patient to be included in the study. Imaging Technique Frontal and lateral radiographs were available in all patients (n =34). Preoperative MRIs (n = 34) were performed on an outpatient ambulatory care 1.5-T superconducting magnet (Signa, GE Healthcare). MRI standard sequences covering the wrist joint region were used with a vitamin capsule demarcating the pain region. dedicated, 4-channel phased-array wrist coil was used in all cases with the patient in the supine position with the hand by the patient s side. standard MRI protocol was used for all patients. T1- weighted images were acquired in the coronal and axial planes with TR range/te, /17; matrix size, ; number of excitations, 4; and field of view, 10 with 3-mm slice thickness and a slice gap of 1 mm. Fat-saturated T2-weighted MR images were acquired in the axial plane by using a fast spin-echo technique with 3,400 6,000/85 102; matrix size, ; number of excitations, 4; field of view, 10; and slice thickness, 3 mm with a slice gap of 1 mm. STIR images were obtained with 3,540/17; inversion time, 150; matrix size, ; number of excitations, 4; 3-mm slice thickness; and 0-mm gap. oronal plane gradient-echo images with a matrix were performed with a slice thickness of 1 mm and no gap. Fig year-old woman with MRI showing characteristic features of ganglion of dorsal aspect of wrist., Focal, relatively large mass (arrows) is evident on T1-weighted image. Placement of vitamin capsule to demarcate patient s pain site has slightly displaced soft tissues. linically, however, no soft-tissue swelling was evident., orresponding fast spin-echo T2-weighted axial image shows focal, fluid cystic mass (arrows) with internal septa (asterisk)., fter administration of IV contrast agent, wall enhancement is evident (arrows). Surgery confirmed ganglion as diagnosis. There was no joint involvement. ll patients received IV gadopentetate dimeglumine (Magnevist, Schering), at a dose of 0.1 mmol/kg of body weight. ontrast-enhanced fatsuppressed T1-weighted images (n =26) were acquired in both the coronal and axial planes. Fat suppression was accomplished by using selective presaturation of lipid-resonant frequency. ll axial images were performed at the exact same location to allow correlation of findings and anatomy. Imaging Interpretation The two senior radiologists were blinded to the surgical and histopathology results at the time of readout. MRI criteria were analyzed for their usefulness to differentiate ganglion from synovitis. The criteria were lesion location, size, shape, margins, presence of internal septa, signal characteristics, and contrast-enhancement pattern. Size measurements were acquired from the axial plane T2-weighted images from the maximal side-to-side and superior-toinferior margins of the lesion with the size being calculated as size (mm 2 )=a b, where a = width of the lesion and b = depth of the lesion. Shape was divided into two forms, either diffuse and crescentic or uni- or multilocular and rounded. Margins were characterized as either diffuse or defined. Internal structure JR:186, March

3 nderson et al. within the lesion was defined as with or without the presence of septa. ontrast-enhancement pattern was defined as diffuse enhancement within and throughout the lesion, wall enhancement at the periphery of the lesion, or a combination of both. The site was divided into areas associated with the dorsal aspect of the wrist joint, associated closely with the scapholunate ligament and dorsal midcarpal ligament, or anywhere within the wrist. Tenosynovitis was defined as an enlarged fluid-filled tendon sheath, and tendonosis as an enlargement of the tendon with inhomogeneous signal intensity within the tendon. Lesion signal characteristics were analyzed on both T1- and T2-weighted images and compared with the Fig year-old woman with MRI showing characteristic features of dorsal occult ganglion., xial T1-weighted image shows small, mass-like region (arrow). Vitamin capsule was placed at level of pain and to side so as not to obscure small lesions., orresponding axial fast spin-echo T2-weighted image shows focal high-signal-intensity mass (arrow)., fter contrast administration, T1-weighted fat-suppressed image shows wall enhancement (arrow). This was evident in 50% of dorsal occult ganglion cysts. Small dorsal occult ganglion characteristically is located at dorsal aspect of scapholunate ligament, superficially overlying midcarpal dorsal ligament. D, Histopathology image shows myxoid central portion devoid of gelatin myxoid material (asterisks) and chronic inflammatory wall of ganglion. Note absence of synovial lining. t surgery, dorsal occult ganglion was seen arising from scapholunate ligament, which was subsequently débrided. (H and E, 10) signal intensity of muscle. Review for signs of inflammation of the posterior dorsal nerve with enlargement and contrast enhancement was performed on axial images before and after contrast administration. ll images were interpreted by consensus by two senior radiologists. The radiographs and MR images were interpreted separately and at different sessions. Data were recorded on a specifically created data sheet. Diagnoses included ganglia or synovitis. Ganglia were divided into ganglion and dorsal occult ganglion cysts. Ganglia could be located anywhere in the dorsal aspect of the wrist, and the dorsal occult ganglia were defined by their origin at the scapholunate ligament. Surgery Surgery was performed by the senior hand surgeons of the hand surgery unit. They recorded their surgical findings as part of usual clinical practice, often with diagramatic sketches. These notes were later correlated with the MRI diagnoses. t surgery, the main cyst may be single or multiloculated with a smooth, white, and translucent appearance and is strictly localized compared with the diffuse extension of synovitis, which surrounds tendons and may involve the underlying joint. ganglion cyst may occur anywhere between tendons, but its pedicle connects to the involved joint usually over the scapholunate ligament (as in dorsal occult ganglion cysts) in contrast to D 814 JR:186, March 2006

4 MRI in the hronic Painful Wrist the synovitis that shows diffuse extension without a pedicle. The main cyst and its pedicle are mobilized down to the underlying joint capsule. The ganglion and its capsular attachments including the pedicle are tangentially excised off the involved ligament to prevent recurrence. Posterior dorsal nerve inflammation was defined as a thickened and obviously visible nerve. In tenosynovitis, there is marked thickening of the tendon sheath, which is completely excised. Histopathology MRI findings were correlated with intraoperative findings and histopathology. Fig year-old woman with MRI showing characteristic features of dorsal occult ganglion., xial T1-weighted image shows small focal mass (arrow) adjacent to dorsal aspect of scapholunate ligament., Fast spin-echo T2-weighted fat-suppressed image shows small ganglion (arrow)., fter contrast administration and fat suppression, diffuse contrast enhancement (arrow) is seen within the lesion. D, Histopathologic image shows chronically thickened myxoid wall with very small central pseudolumen (asterisk) (gelatinous material is removed during pathology processing) and with small lesion size, these features presumably account for presence of 50% of diffuse contrast enhancement of dorsal occult ganglion cysts. (H and E, 10) Statistics The differences between dorsal occult ganglion cysts, ganglion, and synovitis using six MRI parameters were assessed by exact Pearson chi-square tests (categoric parameters) and Kruskal-Wallis tests (continuous parameters). p value of less than 0.05 was considered to indicate a statistically significant difference. Discriminant analysis was used to find combinations of parameters that differentiate between diagnoses. The agreement between MRI findings and intraoperative findings was analyzed using the proportion of overall agreement with a lyth- Still-asella confidence interval and the kappa coefficient (proportion of agreement after chance agreement is removed) with a 95% confidence interval. Sensitivity and specificity for each diagnosis (i.e., synovitis, dorsal occult ganglion, and ganglion) were calculated as well. alculations were done in SS software, version 8 (SS Institute) and StatXact, version 5 (ytel Software). Results Patients There were 34 operated patients (23 women, 11 men) ranging in age from 18 to 41 years, with an average age of 29.5 years. There was no statistical difference for patient age or sex. Radiographs ll radiographs (n = 68) were normal in appearance. There was no evidence of soft-tissue swelling, calcification, or bone or joint abnormality. MRI Thirty-five MRI abnormalities were found in 34 operated patients, including 25 ganglia (Fig. 1), 16 of which were dorsal occult ganglia D JR:186, March

5 nderson et al. Fig year-old-man with MRI showing characteristic features of synovitis., xial T1-weighted image shows broad, thin region of altered signal intensity (arrows)., orresponding fast spin-echo fat-suppressed T2-weighted image shows diffuse region of altered signal intensity (arrows)., fter contrast administration, T1-weighted fat-suppressed image shows diffuse contrast enhancement (arrows). D, Histopathologic image shows marked pseudopolypoid-like thickened synovia. (H and E, 2.5) E, t higher power, chronic granulation tissue is also evident within synovial thickening. Note synovial epithelial lining (arrows). t surgery, synovitis was extensive, requiring major stripping. (H and E, 10) D E 816 JR:186, March 2006

6 MRI in the hronic Painful Wrist (Figs. 2 and 3), and six cases of synovitis (Fig. 4) (Table 1). MR diagnosis was confirmed by surgery with an overall agreement of 71% (95% confidence interval [I], 55 85%) and an overall kappa of 0.57 (95% I, ). In four cases, the MRI diagnosis (two ganglion cysts and two synovitis) could not be confirmed at surgery. In two cases, MRI diagnosed ganglia that intraoperatively were found to be synovitis. Two cases of synovitis were diagnosed as ganglia on MRI and intraoperatively found to be dorsal occult ganglion cysts. In one case, the MRI diagnosis was consistent with a fibrosed tendon but was found to be tenosynovitis at surgery and pathology. There were no cases of dorsal occult ganglia associated with posterior dorsal nerve inflammation. orrelation with Surgery or Surgery and Histopathology The MRI diagnosis was correlated with surgery in all 34 patients and, in addition, with histopathology in 24 (70%) of 34 patients (Table 2). There was sensitivity for ganglia of 89% (95% I, 56 99%) and for dorsal occult ganglion cysts of 94% (95% I, %). Regarding the small synovitis group, there was very low correlation mirrored by a low sensitivity of 33% but with an acceptable specificity of 86%. nalysis of MRI Features to Differentiate Ganglion and Synovitis Six MRI criteria were analyzed for their usefulness to differentiate ganglion from synovitis. MRI signal characteristics were not useful in distinguishing between ganglion and synovitis. The margins, either diffuse or defined, proved to be statistically significant in differentiating between synovitis and ganglion (p < 0.001). The diffuse crescentic shape was typical for synovitis in comparison with the uni- or multilocular rounded shape of a ganglion (p < 0.001). The site was statistically significant in separating dorsal radiocarpal joint associated synovitis from ganglia located anywhere in the wrist, and from the dorsal occult ganglion cyst with its origin at the scapholunate ligament (p < 0.001). Ganglia were larger in size (> 0.5 mm 2 ) than dorsal occult ganglion cysts and synovitis (< 0.5 mm 2 ). In addition, synovitis was differentiated in size from ganglia, with synovitis covering a broad and thin area and ganglia having a narrower width (p < 0.001). Ganglia and dorsal occult ganglion cysts commonly had a width less than 8 mm, whereas synovitis was commonly greater than 8 mm in width. Ganglia commonly had a depth greater than 3 mm, whereas dorsal occult ganglion cysts and synovitis commonly had a depth less than 3 mm. In synovitis, there is usually no septation in the internal structure; however, septa are commonly present in two thirds of ganglia and in one half of dorsal occult ganglion cysts (p = 0.003). Internal septa were present in a single case of synovitis. ontrast enhancement was diffuse in synovitis compared with a wall enhancement in ganglia (p < 0.001), and in dorsal occult ganglion cysts there was either diffuse (50%) or wall (50%) enhancement. The main criteria and results are summarized in Table 3. With multivariate analysis, the criteria margin (p < 0.001) and site (p < 0.001) are sufficient for differentiating between ganglion and synovitis (100%). Margin separates synovitis from dorsal occult ganglion cysts and ganglion; site separates dorsal occult ganglion cysts and ganglion. Discussion Dorsal chronic wrist pain is clinically difficult. Patients have often suffered long-term pain, sought advice from many medical sources with no effect, and may even have been labeled as malingerers. Often the diagnosis is not known. Though a large number of etiologies [1, 2] may be associated with the chronic painful dorsal wrist, very little information is available regarding causation and diagnosis with the literature dominated by the diagnosis of pannus and synovitis associated with rheumatoid arthritis. Some etiologies such as the dorsal occult ganglion have been assessed with MRI [4, 5]. The natural history of undiagnosed wrist pain, particularly in the young, may be disabling, with some 40% significantly troubled after long-term follow-up of more than 10 years [6]. subset of ganglia are thought to cause chronic pain secondary to or related to internal derangements of the wrist and ligament tears [7, 8]. The significance of being able to distinguish between the two entities is important, and preoperative MRI may allow a specific diagnosis. Patients with chronic synovitis may undergo a longer trial period of conservative treatment, and if surgery is required it may be more extensive. Patients with chronic dorsal wrist pain due to a ganglion are more likely to go to surgery earlier and the operation is more targeted with resection of the ganglion and inspection and débridement of any associated ligament tears. Our series has shown that MRI of dorsal chronic wrist pain is accurate in distinguishing between synovitis and ganglion. fter review of the results, many MRI features are intuitive, but they have not been previously formally tested. hronic synovitis and ganglion cysts are histopathologically different. Synovitis consists of a synovial proliferation with an inflammatory cellular response with lymphocytes, plasma cells, and occasional macrophages. ganglion cyst consists of a myxoid wall with benign fibroblastic collagen and has no epithelial synovial lining. There may be evidence of a light chronic inflammatory cellular reaction in the myxoid wall, and there is myxoid degeneration with a gelatinous fluid center [2]. ecause the wrist region may be associated with a large number of incidental ganglion cysts [2], we recommend the usual practice of demarcating the patient s pain with a marker, such as a TLE 1: MRI Diagnosis orrelated with Surgical and Histologic Diagnosis Surgical and Histologic Diagnosis Dorsal Occult No Intraoperative MRI Diagnosis Ganglion Ganglion yst Synovitis Diagnosis Total Ganglion Dorsal occult ganglion cyst Synovitis Other disease Total TLE 2: Summary of Statistical nalysis of MRI riteria Differentiating Ganglion from Synovitis Statistical nalysis Ganglion Dorsal Occult Ganglion yst Synovitis Sensitivity 89% (95% I: 56 99) 94% (95% I: ) 33% (95% I: 6 73) Specificity 85% (95% I: 67 95) 95% (95% I: ) 86% (95% I: 70 95) κ 0.66 (95% I: ) 0.88 (95% I: ) 0.2 (95% I: ) Note I = confidence interval. JR:186, March

7 nderson et al. TLE 3: Summary of MRI Features for Diagnosis of Synovitis Versus Ganglion ppearance Synovitis Dorsal Occult Ganglion yst Ganglion Feature Margins (p < 0.001) Diffuse Defined Defined Shape (p < 0.001) Diffuse crescentic Unilocular, multilocular Multilocular Site (p < 0.001) Dorsal wrist Scapholunate ligament, dorsal nywhere midcarpal region Size (p < 0.001) (mm 2 [a b]) a=depth (p = 0.002) b = width (p <0.001) road and thin, < 0.5 mm 2 < 0.5 mm 2 > 0.5 mm 2 Internal structure (p = 0.003) No septa Septa ± Septa Enhancement after administration Diffuse enhancement Diffuse or wall enhancement Wall enhancement of contrast material (p < 0.001) Note p value of less than 0.05 was considered statistically significant. ± = may or may not be associated with. vitamin capsule, before the MRI. This was done in our series and we had no confusion with additional incidental findings. We found the use of contrast administration very helpful in this clinical setting. It was statistically significant in distinguishing between ganglion and synovitis. Some overlap of a diffuse contrast-enhancement pattern usually associated with synovitis was seen in some of the small dorsal occult ganglion cysts, which related to their smaller size and presumably thicker wall with a smaller central luminal surface area and thus shorter time for intracystic dispersal of contrast material (Fig. 3). pitfall of our study was its retrospective nature. nother was that not all MRI diagnoses correlated with the surgical or histologic diagnosis. This presumably relates to both entities having some form of dynamic inflammation or irritation. We obtained 2D measurements of the lesions because 3D volume sequences had not been performed. The 3D measurements may add further information. We did not compare MRI with sonography because the aim of our study was to determine MRI criteria useful in distinguishing ganglion from synovitis in dorsal chronic wrist pain. Sonography has been found to be generally useful in imaging the hand in patients with persistent pain and suspected occult ganglion [8]. The efficacy of MRI and sonography in diagnosing the presence of dorsal occult ganglion cysts is similar [9 11]; however, MRI offers an objective, reproducible display of anatomic relationships. MRI is not as user-dependent as sonography, though with improved technique, for example with advanced use of panorama sonography, in the future sonography may be the imaging technique of first choice and MRI may be used for more difficult cases. If so, we hope the presented criteria may be helpful. nother positive aspect to this study is that all pain is not necessarily related to ganglia, and having a definitive diagnosis, as well excluding other sinister diagnoses, is helpful in this clinical setting. In conclusion, MRI is a helpful preoperative tool in distinguishing between ganglion and synovitis in the chronic painful dorsal wrist. MRI is diagnostically helpful with chronic wrist pain without obvious swelling. haracteristically, ganglia have defined margins, are spherical in shape, are multilocular with septa, and have wall enhancement. haracteristically, synovitis will have diffuse margins, be crescentic in shape over a broad thin area, lack septa, and have evidence of diffuse enhancement. cknowledgments Many thanks to Daniel Dietrich, Department of Statistics, University of ern, for statistical analysis and support. Thanks also to Karin Kohler and Elisabeth Haefeli for image preparation and to Susanne Furrer for manuscript support. References 1. hidgey LK. hronic wrist pain. Orthop lin North m 1992; 23: ngelides. Ganglions of the hand and the wrist. In: Green DP, ed. Operative hand surgery, 4th ed. New York, NY: hurchill Livingstone, 1999: Wolfe SW. Tenosynovitis. In: Green DP, ed. Operative hand surgery, 4th ed. New York, NY: hurchill Livingstone, 1999: Hollister M, Sanders R, Mcann S. The use of MRI in the diagnosis of an occult ganglion cyst. Orthop Rev 1989; 28: Vo P, Wright T, Hayden F, Dell P, hidgey L. Evaluating dorsal wrist pain: MRI diagnosis of occult dorsal wrist ganglion. J Hand Surg m 1995; 20: Ryley JP, Langstaff RJ, arton NJ. The natural history of undiagnosed wrist pain in young women: a long-term follow-up. J Hand Surg r 1992; 17: Povlsen, Pekett WR. rthroscopic findings in patients with painful wrist ganglia. Scand J Plast Reconstr Surg Hand Surg 2001; 35: el-noueam KI, Schweitzer ME, lasbalg R, et al. Is a subset of wrist ganglia the sequela of internal derangements of the wrist joint? MR imaging findings. Radiology 1999; 212: Osterwalder JJ, Widrig R, Stober R, Gachter. Diagnostic validity of ultrasound in patients with persistent wrist pain and suspected occult ganglion. J Hand Surg m 1997; 22: ardinal E, uckwalter K, raunstein EM, Mih. Occult dorsal carpal ganglion: comparison of US and MR imaging. 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