Morton neuroma: effect of MR imaging findings on diagnostic thinking and therapeutic decisions

Magnetic Resonance Neurography of the Foot and Ankle

Peripheral neuropathies of the foot and ankle can be challenging to diagnose clinically due to concomitant traumatic and nontraumatic or degenerative orthopedic conditions. Although clinical history, physical examination, and electrodiagnostic testing comprised of nerve conduction velocities and electromyography are used primarily for the identification and classification of peripheral nerve disorders, MR neurography (MRN) can be used to visualize the peripheral nerves as well as the skeletal muscles of the foot and ankle for primary neurogenic pathology and skeletal muscle denervation effect. Proper knowledge of the anatomy and pathophysiology of peripheral nerves is important for an MRN interpretation.

Magnetic Resonance Neurography of the Foot and Ankle

Peripheral neuropathies of the foot and ankle can be challenging to diagnose clinically due to concomitant traumatic and nontraumatic or degenerative orthopedic conditions. Although clinical history, physical examination, and electrodiagnostic testing comprised of nerve conduction velocities and electromyography are used primarily for the identification and classification of peripheral nerve disorders, MR neurography (MRN) can be used to visualize the peripheral nerves as well as the skeletal muscles of the foot and ankle for primary neurogenic pathology and skeletal muscle denervation effect. Proper knowledge of the anatomy and pathophysiology of peripheral nerves is important for an MRN interpretation.

Presurgical Perspective and Postsurgical Evaluation of Morton's Neuroma and Other Nerve Lesions

Magnetic resonance imaging (MRI) is a robust method used for both preoperative and postoperative evaluation of Morton's neuroma and other neural lesions. MRI is used to confirm the diagnosis and for precise localization, estimation of outcome, and differential diagnoses. The differential diagnoses include mechanically induced plantar plate ruptures with associated Morton's neuroma-like tumors in the intermetatarsal/interdigital spaces; mechanical fibrosis cushion formations and pseudo bursae in the plantar foot adipose tissue; rheumatologic affections, such as rheumatoid nodules, gouty nodules, and intermetatarsal bursitis; and lastly the tenosynovial giant cell tumor (formerly called pigmented villonodular synovitis). In the postoperative evaluation after resection of Morton's neuroma, the same differential diagnoses must be considered as in the preoperative evaluation. Similarly, a high prevalence (up to 25%) of asymptomatic Morton's neuroma-like findings in the intermetatarsal and interdigital spaces should be kept in mind when interpreting postoperative recurrent forefoot pain after Morton's neuroma resection.

Treatment of Morton's neuroma with minimally invasive distal metatarsal metaphyseal osteotomy (DMMO) and percutaneous release of the deep transverse metatarsal ligament (DTML): a case series with minimum two-year follow-up

BACKGROUND

The optimal treatment of symptomatic Morton's neuroma remains unclear; conservative methods are sometimes ineffective and neurectomy has significant rates of patient dissatisfaction. The aim of this study was to evaluate the outcome of minimally invasive distal metatarsal metaphyseal osteotomy (DMMO) and percutaneous release of the deep transverse metatarsal ligament (DTML) in patients with Morton's neuroma.

METHODS

Between January 2018 and November 2019, 27 patients (29 feet) diagnosed with Morton's neuroma after clinical and radiological evaluation underwent DMMO and percutaneous DTML release. The primary clinical outcomes were pain (VAS) and function (AOFAS score). Secondary outcomes included patient satisfaction, complications, and radiographic outcomes. Patients were followed up for a minimum of two years.

RESULTS

The median age of the participants was 66 years (range 48-79) and the follow-up time was 28 months (24-47). There was a decrease of 5.7 points in the VAS for pain (p < .001) and an increase of 19.9 in AOFAS (p < .001) after the surgical procedure. There was one case of superficial infection and one patient required resection of the neuroma (neurectomy). The majority of patients (89.7%) were satisfied and considered the procedure outcome as excellent or good.

CONCLUSION

Treatment of Morton's neuroma with minimally invasive distal metatarsal metaphyseal osteotomy and percutaneous release of the deep transverse metatarsal ligament showed significant improvement in pain and function with a low incidence of complications and a high rate of personal satisfaction.

The Vulcan salute sign: a non-sensitive but specific sign for Morton's neuroma on radiographs

OBJECTIVES

To assess the value of the divergence of toes on conventional radiographs of the foot for diagnosing Morton's neuroma.

METHODS

This retrospective case-control study was approved by the local ethics committee. In 100 patients with MRI-proven Morton's neuroma 2/3 or 3/4 (study group) and 100 patients without (control group), conventional weight-bearing dorso-plantar view radiographs were evaluated for the subjective presence of interphalangeal divergence, called the Vulcan salute sign or V-sign, by two blinded, independent musculoskeletal radiologists. Interphalangeal angles (2/3 and 3/4) and intermetatarsal angle I/V were measured. The t test and chi-squared test were used to compare the groups. Diagnostic performance was calculated. Interobserver reliability was assessed using κ statistics and intraclass correlation coefficient (ICC).

RESULTS

The difference between the groups was significant (P < 0.05) regarding the presence of the V-sign, which was found in 30 of 100 patients with Morton neuroma and in 3 of 100 control patients, with a sensitivity of 30% and a specificity of 97%. The differences between interphalangeal angles were significant (P < 0.05) between the groups. The interphalangeal angle 2/3 mean values were 7.9° (± 4.8) for the study group vs 5.4° (± 2.6) for the controls; the 3/4 angle values were 6.5° (± 3.8) and 3.4° (± 2.5), respectively. There was no significant difference between the groups in the intermetatarsal angle I/V. Interobserver agreement was substantial for the V-sign, with a κ value of 0.78. The ICC was excellent concerning angle measurements, with all values ≥ 0.94.

CONCLUSION

The Vulcan salute sign on conventional radiographs is specific for Morton's neuroma.

ACR Appropriateness Criteria® Chronic Foot Pain

Chronic foot pain is a frequent clinical complaint, which can significantly impact the quality of live in some individuals. These guidelines define best practices with regards to requisition of imaging studies based on specific clinical scenarios, which have been grouped into different variants. Each variant is accompanied by a brief description of the usefulness, advantages, and limitations of different imaging modalities. The present narrative is the result of an exhaustive assessment of the available literature and a thorough review process by a panel of experts on Musculoskeletal Imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Interdigital Commissural Approach for Morton's Neuroma

BACKGROUND

Morton's neuroma is a frequent cause of metatarsalgia. Operative treatment is indicated if nonoperative management has failed. The objective of the present study was to describe a technique of Morton's neuroma excision by a minimally invasive commissural approach and evaluate the long-term outcome and complications.

METHODS

A retrospective study of 108 patients with Morton's neuroma treated surgically with a commissural approach between September 1990 and December 2010 was performed. The surgical technique is described. Clinical outcomes and complications were evaluated. The average follow-up was 121 months. Eleven patients were men and 97 women. The average age was 49.4 years; 56.8% neuromas were at the third space and 43.2% at the second space. Six patients presented 2 neuromas in the same foot, and 9 patients had bilateral neuroma.

RESULTS

The visual analog scale (VAS) average pain score was 5.4 points preoperatively and 0.2 points at the final follow-up. The author found a significant difference between the VAS scores preoperatively and postoperatively (P < .01). Excellent and good satisfaction outcomes were achieved in 93.6%. The postoperative complication incidence was 3%.

CONCLUSION

The author believes a minimally invasive commissural approach has advantages over a dorsal or plantar incision. It is a simple and reproducible technique, with satisfactory outcomes, low complication rates, and a quick return to usual activities.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

The effectiveness of shoe modifications and orthotics in the conservative treatment of Civinini-Morton syndrome: state of art

Civinini Morton’s Syndrome (CMS), better known as Morton’s Neuroma, is a benign enlargement that typically affects the third common digital branch of the plantar nerve. It is a common cause of metatarsalgia leading to debilitating pain. It prefers the female gender, with a female to male ratio of 5:1 and an average age of 50 years at time of surgery. Precise aetiology remains under debate, with four etiopathogenetic theories often cited in the literature. Clinical symptoms, physical exam and instrumental evidence are important in assessing and grading the disease. Biomechanics seem to play an important role, especially regarding the usefulness of correct footwear. The first approach in the early stages of this condition usually begins with shoe modifications and orthotics, designed to limit the nerve compression. In order to prevent or delay the development of CMS, shoes should be sufficiently long, comfortable, broad toe-boxed, should bear a flat heel and a sufficiently thick external sole which should not be excessively flexible. Most authors suggested that an insole with medial arch support and a retrocapital bar or pad, just proximal to the metatarsal heads, displaces the pressure sites and can be beneficial to relieve the pain from the pinched nerve. A threshold period of 4.5 months appears to emerge from the results of the analysed studies, indicating that, beyond this period and in neuromas larger than 5-6 mm, orthotics and/or shoes modifications do not seem to give convincing results, proving to be more a palliation for the clinical condition to allow an acceptable life with pain rather than a real treatment. (www.actabiomedica.it)

Intermetatarsal bursitis as first disease manifestation in different rheumatological disorders and related MR-imaging findings

Metatarsalgia defined as pain at the plantar aspect of the forefoot. Intermetatarsal bursitis is considered one potential soft-tissue cause of metatarsalgia that is presumably under-estimated, under-investigated, and, consequently, often misdiagnosed. To assess the role of MRI in the elucidation of the cause of metatarsalgia in patients with different autoimmune disorders presenting primarily with this symptom and to present the accompanying clinical and radiological findings of intermetatarsal bursitis. Retrospective evaluation of the medical records of patients with different rheumatological conditions claiming primarily of pedal pains suggests metatarsalgia and who underwent, therefore, all magnetic resonance imaging between March 2010 and April 2018. Of them, six patients fulfilled these criteria and were diagnosed subsequently with intermetatarsal bursitis. Several underlying autoimmune conditions were diagnosed. All patients were clinically assessed by the squeeze test and radiologically investigated with MRI; three patients underwent additional sonography. All patients presented intermetatarsal bursitis as first disease manifestation. The number of involved bursae ranged from one to three on one side. The main MR findings were distension of the intermetatarsal bursa with increased signal intensity on T2-weighted and post-contrast fat saturation T1-weighted images. Most frequent locations were the second and third intermetatarsal spaces. The size of the intermetatarsal bursitis and its plantar extension were correlated in all patients. Intermetatarsal bursitis can potentially be the first manifestation of different rheumatological diseases. Awareness of this potential association as well as cognizance of its imaging findings can help for making a more accurate and prompt earlier diagnosis of the underlying disease changing also the therapeutic approach.

Sclerosing alcohol injections for the management of intermetatarsal neuromas: A systematic review

An intermetatarsal neuroma is a plantar digital neuritis causing metatarsalgia of the affected inter-metatarsal space. At present the evidence to support the management of the condition is poor with only some quality evidence supporting the short-term management of intermetatarsal neuromas using steroid injections. Some authors have supported the use of alcohol sclerosing intra-lesional injections to treat intermetatarsal neuromas. Following a search of the evidence 11 articles were identified. The systematic review found that alcohol injections appear to be safe although some papers report a short-term side effect of a flogistic reaction and there are variances in the alcohol concentration used and guiding verses not guiding the injection using ultrasound imaging. Some of the evidence may suggest a sclerosing histological effect of the nerve. However, all the studies reviewed present a research design offering a low level of evidence that is open to methodological biases and interpretation. Thus, this review found insufficient high-quality research evidence to afford conclusions on the management of intermetatarsal neuromas with alcohol sclerosing agent injections.

Ultrasound-Guided Percutaneous Radiofrequency for the Treatment of Morton's Neuroma

PURPOSE

Morton's neuroma (MN) is a leading cause of disability. The purpose of this study was to investigate the effectiveness of radiofrequency (RF) in patients with chronic pain refractory to conservative therapies.

METHODS

Between September 2012 and December 2016, RF was performed on 52 patients. A sterile RF needle probe (22G, 5-cm needle with 10-mm electrode active tip) was inserted between the toes into the intermetatarsal space at the center of the lesion. Potential complications of the intervention and post-procedure care were examined. All patients provided written, informed consent. All percutaneous procedures were performed with the NeuroTherm^® NT1100 (Neurotherm Inc., M.) device and using ultrasound guidance (Philips IU22). Continuous RF was performed with one cycle of 90 s and with the probe tip maintaining a temperature of 85 °C (impedance 95-210 mΩ).

RESULTS

Mean VAS score before the procedures was 9.0 ± 0.6. A reduction of pain intensity was achieved after 1 week by RF (mean VAS scores 3.7 ± 0.9; p < 0.05), with a stabilization of the painful symptomatology in the following months and after 1 year of treatments (mean VAS scores 2.0 ± 0.4 after 12 months, p < 0.05). The FHSQ scores showed improved quality of life (QOL) in all patients at 6 months (p < 0.05) and 1 year (p < 0.05) of RF. No patients developed complications.

CONCLUSIONS

RF is a safe, efficient, and minimally invasive technique for the treatment of symptomatic MN.

Postoperative Foot and Ankle MR Imaging

MR imaging has an important role in the evaluation of the postoperative foot and ankle. In this article, a variety of operative techniques and postoperative findings in the foot and ankle are described, including tendon and ligament reconstruction, as well as the treatment of tarsal coalition and Morton neuroma. The role of MR imaging in the assessment of complications of foot and ankle surgery is also detailed.

Ultrasound Evaluation of Morton Neuroma Before and After Laser Therapy

OBJECTIVE

The objective of our study was to retrospectively assess for differences in imaging appearances of Morton neuromas before and after laser therapy using diagnostic ultrasound (US).

MATERIALS AND METHODS

A retrospective review was performed to identify patients who underwent US imaging to evaluate for Morton neuroma during the study period (June 1, 2013-July 1, 2014); of the 42 patients identified, 21 underwent US evaluations before and after laser therapy. US reports and images were reviewed and correlated with clinical history. The final study group consisted of 21 patients who had a total of 31 Morton neuromas evaluated using US after treatment. A retrospective review was then performed to characterize the appearances of these lesions before and after therapy followed by an analysis of variables.

RESULTS

Retrospective US review of 31 pretreatment Morton neuromas showed fusiform, heterogeneously hypoechoic masses with well-defined borders in most cases and that pain was reported when transducer pressure was applied in 97% (30/31) of cases. After treatment, lesions showed ill-defined borders (23/31), and pain with application of transducer pressure was either significantly decreased or absent (29/31); these findings were concordant with the clinical findings. Both of these characteristics were statistically significant (p < 0.0001). In addition, more Morton neuromas occurred in the second intermetatarsal space than in the third intermetatarsal space (p < 0.0001).

CONCLUSION

US may be used to identify posttreatment changes after laser therapy of Morton neuromas. Posttreatment changes include ill-defined borders and less pain or the absence of pain with the application of transducer pressure. These criteria may be applied in future clinical studies evaluating the efficacy of laser therapy for Morton neuroma.

Evaluation of lesser metatarsophalangeal joint plantar plate tears with contrast-enhanced and fat-suppressed MRI

OBJECTIVE

To present findings of plantar plate (PP) lesions from MRI with administration of gadolinium and to differentiate PP lesions from others causes of metatarsalgia.

MATERIALS AND METHODS

Two musculoskeletal radiologists reviewed 249 contrast-enhanced forefoot MRI scans from patients with metatarsalgia between June 2012 and June 2013. Evaluations focused on hyper-vascularized/fibrous tissue and other findings associated with PP tears.

RESULTS

Fifty-nine patients had PP tears, 59 % were female. Most of these patients, 48/59 (81.4 %), had a single metatarsophalangeal (MTP) PP lesion in one foot, although 7/59 patients had one lesion in each foot, 3/59 (5.1 %) had two in one foot, and 1/59 (1.7 %) had three lesions in one foot. The second MTP joint was the most common location for PP tears (n = 56), followed by the third (n = 12) and fourth (n = 3) MTP joints. Lateral (n = 33) and full thickness (n = 28) PP lesions were the most frequent, and central (n = 3) and lateral/central (n = 7) tears were less prevalent. Fifty (70.5 %) PP lesions showed pericapsular fibrosis in pre-contrast sequences, and 21 (29.5 %) were visible only after administration of gadolinium. All PP lesions had collateral ligament involvement. Others findings included interosseous tendon lesions (n = 29), interosseous tendon rupture (n = 29), synovitis (n = 49), flexor tenosynovitis (n = 28), crossover toe (n = 2), hammertoe (n = 1), intermetatarsal space (IS) neuromas (n = 11), and third IS neuromas (n = 12).

CONCLUSION

PP tears are a common cause of metatarsalgia, accounting for more than 20 % of cases in our sample. A substantial portion of the lesions (29.5 %) became visible only after the administration of gadolinium.

Diagnostic Value of Elastography in the Diagnosis of Intermetatarsal Neuroma

The objective of the present study was to characterize the ultrasound and elastographic properties of intermetatarsal neuroma (interdigital neuroma) and their contribution to diagnosis. Eighteen patients with metatarsalgia, who had presented to an orthopedic clinic from April 2013 to February 2015, were diagnosed with 25 intermetatarsal neuromas (11 unilateral [61.11%], 7 bilateral [38.89%]). These patients underwent evaluation with ultrasonography and simultaneous ultrasound strain elastography to assess the elastographic properties of the tissues in the intermetatarsal space. The intermetatarsal neuroma diagnosis was confirmed by histopathologic inspection. The lesion contours, localization, dimensions, and vascularization were evaluated before surgical excision. The elasticity and strain ratio values were compared between the neuroma and adjacent healthy intermetatarsal space. Of the 25 intermetatarsal neuromas, 1 (4%) was not detected by ultrasonography (incidence of detection of 96%). The mean neuroma width was 6.35 (range 3.7 to 13) mm in the coronal plane, and the mean elasticity and strain ratio values were 3.44 (range 1.1 to 5.1) and 9.47 (range 2.3 to 19.3), respectively. The elasticity and strain ratio values were significantly greater in the presence of an interdigital neuroma than in the adjacent healthy intermetatarsal spaces (Z = -3.964, p = .0001 and Z = -3.927, p = .0001, respectively). The diagnostic cutoff values were calculated as 2.52 for elasticity and 6.1 for the strain ratio. Four neuromas (16%) were not demarcated, and the elasticity and strain ratio values for these were lower than those for neuromas with demarcated contours but were greater than those for healthy intermetatarsal spaces (p < .006 and p < .005, respectively). Patients with clinically suspected intermetatarsal neuromas that do not show demarcation and with smaller lesions might benefit from the use of ultrasound elastography for diagnosis.

Excision of Morton's Neuroma Using a Longitudinal Plantar Approach: A Midterm Follow-up Study

BACKGROUND

Operative procedures are indicated in the treatment of Morton's neuroma (MN) when conservative therapies have been unsuccessful. A dorsal approach for neurolysis or neurectomy was strongly recommended. The aim of this case series study was to prospectively analyze the midterm clinical outcome and complications following the excision of a MN using a plantar longitudinal approach.

METHODS

Between September 2000 and January 2009, we included 44 patients (51 feet, 56 neuromas) in a prospective study treated by excision of a primary MN using a plantar longitudinal approach. The MN diagnosis was based on clinical symptoms, magnetic resonance imaging findings, and pain relief after infiltration of local anesthetics. Histological examinations were performed in all resected specimens. The patients returned for final follow-up at a mean of 54 (range = 12 to 99) months, comparing preoperative and postoperative perception of pain on a Visual Analogue Scale (VAS) and assessing clinical findings.

RESULTS

The average amount of pain, according to VAS, was 8 (range = 6-9) points preoperatively and 0.4 (range = 0-5) points at final follow-up. Complications occurred in 7.1% of interventions and scar problems in 5.2%, including delayed wound healing, hypertrophic scar formation, and inclusion cyst.

CONCLUSION

The present study shows a strong relief of pain after MN resection using a plantar longitudinal incision, coupled with a low rate of local complications. This surgical procedure seems to be a reliable choice for the excision of MN, even in cases with MN in adjacent webspaces, because it is technically simple and the plantar scar is not bothersome if properly located.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Prospective, Case series.

Lower Extremity Injury Patterns in Elite Ballet Dancers: Ultrasound/MRI Imaging Features and an Institutional Overview of Therapeutic Ultrasound Guided Percutaneous Interventions

BACKGROUND

Altered biomechanics from repetitive microtrauma, such as long practice hours in en pointe (tip of the toes) or demi pointe (balls of the feet) predispose ballet dancers to a multitude of musculoskeletal pathologies particularly in the lower extremities. Both ultrasound and magnetic resonance imaging (MRI) are radiation-sparing modalities which can be used to confidently evaluate these injuries, with ultrasound (US) offering the added utility of therapeutic intervention at the same time in experienced hands.

QUESTIONS/PURPOSES

The purposes of this paper were: (1) to illustrate the US and MRI features of lower extremity injury patterns in ballet dancers, focusing on pathologies commonly encountered at a single orthopedic hospital; (2) to present complementary roles of both ultrasound and MRI in the evaluation of these injuries whenever possible; (3) to review and present our institutional approach towards therapeutic ultrasound-guided interventions by presenting explicit cases.

METHODS

Online searches were performed using the search criteria of "ballet biomechanics" and "ballet injuries." The results were then further narrowed down by limiting articles published in the past 15 years, modality (US and MRI), anatomical region (foot and ankle, hip and knee) and to major radiology, orthopedics, and sports medicine journals.

RESULTS

Performing ballet poses major stress to lower extremities and predisposes dancer to several musculoskeletal injuries. These can be adequately evaluated by both US and MRI. US is useful for evaluating superficial structures such as soft tissues, tendons, and ligaments, particularly in the foot and ankle. MRI provides superior resolution of deeper structures such as joints, bone marrow, and cartilage. In addition, US can be used as a therapeutic tool for providing quick symptomatic improvement in these athletes for who "time is money".

CONCLUSION

Performing ballet may cause major stress to the lower extremities, predominantly affecting the foot and ankle, followed by the knee and hip. US and MRI play complementary roles in evaluating various orthopedic conditions in ballet dancers, with US allowing for dynamic evaluation and guidance for interventions.

Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis

OBJECTIVES

To compare ultrasound (US) and magnetic resonance imaging (MRI) in the diagnosis of Morton's neuroma.

METHODS

Studies that assessed the diagnostic accuracy of US and MRI for Morton's neuroma were retrieved from major medical libraries independently by two reviewers up to 1 April 2014. Predefined inclusion and exclusion criteria were adopted.

RESULTS

277 studies were initially found, and the meta-analysis was conducted on 14 studies. US sensitivity was studied in five studies, MRI sensitivity in three studies, and bothin six studies. All studies used surgery as the reference standard. A high sensitivity (SE) of diagnostic testing was observed for both US (SE (95 % CI) = 0.91 (0.83-0.96)) and MRI (SE (95 % CI) = 0.90 (0.82-0.96)) with no significant differences between the two modalities in diagnosis (Q test p = 0.88). For MRI, specificity of test was 1.00 with a pooled estimation of 1.00 (0.73-1.00), while the pooled specificity was 0.854 (95 % CI: 0.41-1.00) for US. No differences were observed between US and MRI in study design (p = 0.76).

CONCLUSION

This meta-analysis shows that the SE of US (0.91) is equal to (p = 0.88) that of MRI (0.90) for identification of Morton's neuroma.

KEY POINTS

• For Morton's neuroma, US sensitivity is equal to MRI. • US is as accurate as MRI in diagnosing Morton's neuroma. • US may be the most cost-effective imaging method for Morton's neuroma.

Metatarsalgia and Morton's Disease: Comparison of Outcomes Between Open Procedure and Neurectomy Versus Percutaneous Metatarsal Osteotomies and Ligament Release With a Minimum of 2 Years of Follow-Up

The present study compared the clinical results of open neurectomy versus a percutaneous procedure for Morton's disease. This was a retrospective study comparing the functional results after 2 surgical procedures: open neurectomy and a percutaneous procedure (with deep transverse metatarsal ligament release and distal metatarsal osteotomies). The present study included 52 patients (26 in each group), and the mean follow-up period was 4 (range 2 to 7) years. The patient evaluation criteria included the presence of painful symptoms of Morton's disease, American Orthopaedic Foot and Ankle Society (AOFAS) functional scale score, patient satisfaction, and delay for recovery. Percutaneous treatment of Morton's disease and open neurectomy produced complete relief of pain in 25 of 26 patients in each group. At the latest follow-up visit, the mean AOFAS score had significantly improved from 36 ± 11 preoperatively to a mean of 89 ± 18 (p < .001). After 2 years, the functional improvement obtained with the percutaneous procedure persisted, with a stable AOFAS score (96 ± 10). Persistent metatarsalgia was reported by patients who had undergone open neurectomy, with a significantly decreased AOFAS score (81 ± 21, p = .009). The percutaneous procedure for Morton's disease provided excellent functional outcomes (AOFAS score >90) significantly more often with a shorter delay than after open neurectomy (p = .03). At the latest follow-up visit, metatarsalgia due to plantar hyperpressure or bursitis and requiring plantar orthotics was present in 11 of 26 patients (44%) after open neurectomy and in 1 of 26 patients (4%) after the percutaneous procedure (p = .002). Percutaneous treatment of Morton's disease is a reliable procedure providing results as good as those after open neurectomy, with significantly better outcomes in the longer term and a lower rate of late metatarsalgia.

Effectiveness of the dorsal thermoplastic locking orthosis to prevent floating toes in postoperative follow-up of Weil osteotomies: pilot study

BACKGROUND

The Weil oblique distal metatarsal osteotomy is regularly used in the treatment of primary metatarsalgia. The most frequent complication is the floating toe, which occurs in up to 36% of postoperative follow-up. The theory of reducing the plantar flexor mechanism tension associated with the retraction of the dorsal structures during the healing process of the surgical procedure may explain this negative evolution.

OBJECTIVE

This study aimed at assessing the effectiveness of the Tucade dorsal thermoplastic locking orthosis in the prevention of floating toe after Weil osteotomy.

METHODS

In all, 30 patients with metatarsalgia diagnosis submitted to Weil osteotomy were treated in the postoperative period with the Tucade dorsal thermoplastic locking orthosis.

RESULTS

The floating toe was not observed in this case series. There was 1 case of superficial wound irritation at the dorsal surgical incision and 1 case that evolved with transfer metatarsalgia. Statistical analyses were performed-American Orthopaedic Foot and Ankle Society Scale for lateral toes and extension of the lateral toes-using the t test, and P < .0001 was obtained for comparison of the preoperative and postoperative periods in the population studied.

CONCLUSION

The Tucade dorsal thermoplastic locking orthosis during the postoperative period of Weil osteotomy proved to be effective in the prevention of floating toes.

LEVEL OF EVIDENCE

Therapeutic Level IV: Case Series.

MRI of lesser metatarsophalangeal joint plantar plate tears and associated adjacent interspace lesions

OBJECTIVE

To identify the variety of second and third intermetatarsal space (IS) lesions that may coexist with and without adjacent metatarsophalangeal joint (MTP) plantar plate (PP) tears.

MATERIALS AND METHODS

One hundred forefoot MRIs in 96 patients with metatarsalgia obtained between 30 September 2011 and 21 July 2012 using 1.5- or 3-T MRI were retrospectively reviewed in consensus by two MSK radiologists and one podiatrist (DPM). MRI was evaluated for second and third MTP PP tear and the presence/nature of second and third IS lesions. Second and third IS neuromas were measured in transverse (trans) dimension.

RESULTS

A total of 40 PP tears were identified: 36 at the second and 4 at the third MTP. Second MTP PP tear was identified in 33% of females and 40.5% of males. In the 63 female feet there were 21 second MTP PP tears, all of which also had second IS lesions: pericapsular fibrosis (16), bursitis (4), and ganglion (1). In the 37 male feet there were 15 second MTP PP tears, 14 of which had second IS lesions: pericapsular fibrosis (8), bursitis (5), and ganglion (1). There was no definite second IS neuroma adjacent to any second MTP PP tear. In females without PP tear, there were 24 second (3 mm trans average) and 43 third IS neuromas (4.1 mm trans average). In males without PP tear, there were 9 second (3.4 mm trans average) and 16 third IS neuromas (4.1 mm trans average).

CONCLUSIONS

MTP PP tears occurred in 40% of our cases, 90% of which occurred at the second MTP. Almost all coexisted with non-neuromatous second IS lesions.

Entrapment neuropathies in the upper and lower limbs: anatomy and MRI features

Peripheral nerve entrapment occurs at specific anatomic locations. Familiarity with the anatomy and the magnetic resonance imaging (MRI) features of nerve entrapment syndromes is important for accurate diagnosis and early treatment of entrapment neuropathies. The purpose of this paper is to illustrate the normal anatomy of peripheral nerves in the upper and lower limbs and to review the MRI features of common disorders affecting the peripheral nerves, both compressive/entrapment and noncompressive, involving the suprascapular nerve, the axillary nerve, the radial nerve, the ulnar nerve, and the median verve in the upper limb and the sciatic nerve, the common peroneal nerve, the tibial nerve, and the interdigital nerves in the lower limb.

Prevalence of interdigital nerve enlargements in an asymptomatic population

BACKGROUND

Morton's neuroma is a common primary diagnosis for referral to foot and ankle surgeons. On presentation, many patients have had an ultrasound reporting the presence of Morton's neuroma, which may not correlate with the clinical examination findings. The prevalence of such sonographic findings in the general population remains unknown.

METHODS

In this observational prospective study, patients with asymptomatic forefeet who were seen by two foot and ankle surgeons for unrelated mid- or hind foot pathology were examined clinically and sonographically for the presence of interdigital nerve thickening. Forty-eight volunteers participated in the study (96 feet). For the purpose of this study, asymptomatic thickenings greater than 5 mm in diameter were termed sonographic neuromas. Ultrasound examination was performed by two specialist musculoskeletal radiologists.

RESULTS

Fifty-four percent of the volunteers (26 of 48) had sonographic nerve thickening and in 17 cases (35.4%) enlarged nerves were found bilaterally. Differences for gender, original diagnosis or side of original pathology were not significant. Older subjects were more likely to have a sonographic neuroma (p = 0.018). Feet with a positive Mulder's click were more likely to have a sonographic neuroma (p = 0.015).

CONCLUSION

Ultrasound, even in highly skilled hands, has a high rate of incidental finding of an asymptomatic interdigital nerve enlargement, which can lead to a false diagnosis of a Morton's neuroma. Sonographic evidence of Morton's neuroma per se is unreliable unless it is correlated with an equivocal clinical examination. Clinical examination is still the gold standard for the diagnosis of a Morton's neuroma.

MRI and ultrasonography in Morton's neuroma: Diagnostic accuracy and correlation

BACKGROUND

The diagnosis of Morton's neuroma is based primarily on clinical findings. Ultrasonography (US) and magnetic resonance image (MRI) studies are considered complementary diagnostic techniques. The aim of this study was to establish the correlation and sensitivity of both techniques used to diagnose Morton's neuroma.

MATERIALS AND METHODS

Thirty seven patients (43 intermetatarsal spaces) with Morton's neuroma operated were retrospectively reviewed. In all cases MRI or ultrasound was performed to complement clinical diagnosis of Morton's neuroma. In all cases, a histopathological examination confirmed the diagnosis. Estimates of sensitivity were made and correlation (kappa statistics) was assessed for both techniques.

RESULTS

Twenty seven women and 10 men participated with a mean age of 60 years. Double lesions presented in six patients. The second intermetatarsal space was affected in 10 patients and the third in 33 patients. An MRI was performed in 41 cases and a US in 23 cases. In 21 patients, both an MRI and a US were performed. With regard to the 41 MRIs performed, 34 were positive for Morton's neuroma and 7 were negative. MRI sensitivity was 82.9% [95% confidence interval (CI): 0.679-0.929]. Thirteen out of 23 US performed were positive and 10 US were negative. US sensitivity was 56.5% (95% CI: 0.345-0.768). Relative to the 21 patients on whom both techniques were carried out, the agreement between both techniques was poor (kappa statistics 0.31).

CONCLUSION

Although ancillary studies may be required to confirm the clinical diagnosis in some cases, they are probably not necessary for the diagnosis of Morton's neuroma. MRI had a higher sensitivity than US and should be considered the technique of choice in those cases. However, a negative result does not exclude the diagnosis (false negative 17%).

High resolution imaging of tunnels by magnetic resonance neurography

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment.

Imaging of nerve entrapment in the foot and ankle

Neuropathies can be a cause of chronic foot and ankle pain. The diagnosis can be elusive given the sometimes nonspecific clinical presentation. Although electrodiagnostic studies are primarily relied on for the diagnosis of nerve impairment, imaging is sometimes helpful in helping define the exact site of the entrapment and whether any masses are present. It is critical for the imager to understand the complex anatomy of these nerves and their adjacent structures, to know the most common locations for their entrapments or injury, and to select the proper imaging modality to improve detection of these difficult-to-diagnose clinical conditions.

Peripheral tumor and tumor-like neurogenic lesions

Neoplasms of neurogenic origin account for about 12% of all benign and 8% of all malignant soft tissue neoplasms. Traumatic neuroma, Morton neuroma, lipomatosis of a nerve, nerve sheath ganglion, perineurioma, benign and malignant peripheral nerve sheath tumors (PNST) are included in this group of pathologies. Clinical and radiologic evaluation of patients with neurogenic tumors and pseudotumors often reveals distinctive features. In this context, advanced imaging techniques, especially ultrasound (US) and magnetic resonance (MR) play an important role in the characterization of these lesions. Imaging findings such as location of a soft tissue mass in the region of a major nerve, nerve entering or exiting the mass, fusiform shape, abnormalities of the muscle supplied by the nerve, split-fat sign, target sign and fascicular appearance should always evoke a peripheric nerve sheath neoplasm. Although no single imaging finding or combination of findings allows definitive differentiation between benign from malign peripheric neurogenic tumors, both US and MR imaging may show useful features that can lead us to a correct diagnosis and improve patient treatment. Traumatic neuromas and Morton neuromas are commonly associated to an amputation stump or are located in the intermetatarsal space. Lipomatosis of a nerve usually appears as a nerve enlargement, with thickened nerve fascicles, embedded in evenly distributed fat. Nerve sheath ganglion has a cystic appearance and commonly occurs at the level of the knee. Intraneural perineuroma usually affects young people and manifests as a focal and fusiform nerve enlargement. In this article, we review clinical characteristics and radiologic appearances of these neurogenic lesions, observing pathologic correlation, when possible.

Pseudotumoural soft tissue lesions of the foot and ankle: a pictorial review

In the foot and ankle region, benign neoplasms and pseudotumoural soft tissue lesions are significantly more frequent than malignant tumours. The pseudotumoural lesions constitute a heterogeneous group, with highly varied aetiology and histopathology. This article reviews the imaging features of the most common pseudotumours of the soft tissues in the foot and ankle. Although the imaging characteristics of several of the lesions discussed are non-specific, combining them with lesion location and clinical features allows the radiologist to suggest a specific diagnosis in most cases.

Sensory nerve conduction in branches of common interdigital nerves: a new technique for normal controls and patients with morton's neuroma

In this article, a new electrodiagnostic approach is described for patients with Morton's neuroma. The new method is based on the anatomic fact that the two branches of the common plantar interdigital nerves innervate the lateral side of one toe and the medial side the next one. This study included 20 normal subjects (aged 28-58 years, 10 men and 10 women) and 4 patients with Morton's neuroma (aged 44-52 years, 4 women). The branches of adjacent common plantar interdigital nerves that innerve one toe were stimulated superficially and separately with half of one toe covered with a piece of medical tape. The recordings were obtained on the posterior tibial nerve at the medial malleolus with needle electrodes. Thus, the difference in latencies of obtained sensory nerve action potentials on the posterior tibial nerve with needle electrode was measured. From normal subjects' data, it was determined that a latency difference value of above 0.17 milliseconds (mean +/- 2.5 SD) in one toe was abnormal. All of the patients with Morton's neuroma showed abnormal interlatency difference values. This new method, which we have developed, is more sensitive, simple to use, does not require extra equipment, and does not cause excessive pain. We suggest that interlatency difference between branches of the common plantar interdigital nerves is a useful and sensitive method for the diagnosis of Morton's neuroma.

The outcome of Morton's neurectomy in the treatment of metatarsalgia

Morton's neuroma is a common cause of metatarsalgia caused by intermetarsal digital nerve thickening. This study reviews the pathology, presentation, symptoms and signs, and patient satisfaction with surgical treatment. Seventy-eight patients (82 feet) were treated for Morton's metatarsalgia by excision of the interdigital nerve. The patients were followed-up for a mean of 4.6 years (range 0.8-8.1 years) and scored using the Foot Functional Index and the American Orthopedic Foot Ankle Society scoring system. In 74 patients the Foot Functional Index was more than 85 (maximum score 100). Seventy-one patients scored more than 90 on the American Orthopedic Foot Ankle Society scoring system with two patients scoring 100 (maximum score). Postoperatively, 82% reported excellent or good results, 10% had a fair result with restriction of activities or pain and 8% had no improvement at all after surgery while 71% had restrictions with footwear.

Métatarsalgie de Thomas George Morton

Plantar interdigital neuroma, also called Morton neuroma, neuralgia, or metatarsalgia, is a perineural fibrosis that induces severe intermittent pain and paresthesia, most frequently between the third and fourth metatarsal heads. This compression syndrome or entrapment neuropathy involves one branch of the common plantar digital nerves. Diagnosis is based essentially on clinical examination. Imaging techniques may be useful in the diagnosis of atypical cases and postoperative recurrences. In most case, conservative treatment (such as orthotic shoes or devices or injections) is successful. When they do not succeed, surgery (neurolysis, neurectomy) may be considered.

Morton neuroma: evaluated with ultrasonography and MR imaging

Objective

The purpose of this study was to compare the diagnostic accuracy of both ultrasonography (US) and magnetic resonance imaging (MRI) for the assessment of Morton neuroma.

Materials and Methods

Our study group was comprised of 20 neuromas from 17 patients, and the neuromas were confirmed on surgery following evaluation with US, MRI, or both US and MRI. The diagnostic criterion for Morton neuroma, as examined by US, was the presence of a round or ovoid, well-defined, hypoechoic mass. The diagnostic criterion, based on MR imaging, was a well defined mass with intermediate to low signal intensity on both the T1- and T2-weighted images. The retrospective comparison between the sonographic and MR images was done by two experienced radiologists working in consensus with the surgical and pathologic correlations.

Results

The detection rate of Morton neuroma was 79% for 14 neuromas from 11 patients who had undergone US followed by an operation. The detection rate was 76% for 17 neuromas from 15 patients who had undergone MRI and a subsequent operation. The mean size of the examined neuromas was 4.9 mm on the US images and it was 5.1 mm on the MRI studies. Ten neuromas (71%) were 5 mm or less as measured by US, and three neuromas were not detected, whereas on the MRI analysis, 10 neuromas (59%) were 5 mm or less and four neuromas were not visualized. Among the patients examined during postoperative follow-up, symptoms were completely relieved in 85% and the symptoms were partially relieved in 15%.

Conclusion

US and MR imaging are comparable modalities with high detection rate for the evaluation of Morton neuroma.

Neuropathies of the foot

Compared with the common neuropathies affecting the hands (carpal tunnel syndrome and ulnar neuropathy), neuropathies of the feet have received less attention in the past. This is partly because of the rarity of these disorders as well as the lack of reliable electrophysiological tests for them. Over the years, nerve conduction tests for various nerves of the feet have been reported, and at this time techniques for all the nerves of the feet are available to the electromyographer. This review will provide up-to-date information on the current status of the research and issues relating to the neuropathies of the foot, with an emphasis on the most useful tests and the caveats for clinical neurophysiologists.

Syndromes canalaires du sportif

Peripheral nerve entrapment syndromes involve the compression of a short segment of a nerve at a specific site, as a result of the vulnerability of that nerve as it passes through a fibroosseous tunnel or an opening in fibrous or muscular tissue. Injury of the nerve may occur as a result of compression by the overlying structures. Another mechanism of injury is traction of the nerve, with or without friction of the nerve, as it travels and sharply changes direction around critical points. Imaging can be particularly helpful for the diagnosis of these uncommon injuries. Percutaneous decompression of a ganglion cyst or perineural injection for therapeutic purposes with the aid of fluoroscopy, CT, or ultrasound guidance can be performed in specific areas.

[Diagnostic imaging of nerve compression syndrome]

Compression-induced neuropathy of peripheral nerves can cause severe pain of the foot and ankle. Early diagnosis is important to institute prompt treatment and to minimize potential injury. Although clinical examination combined with electrophysiological studies remain the cornerstone of the diagnostic work-up, in certain cases, imaging may provide key information with regard to the exact anatomic location of the lesion or aid in narrowing the differential diagnosis. In other patients with peripheral neuropathies of the foot and ankle, imaging may establish the etiology of the condition and provide information crucial for management and/or surgical planning. MR imaging and ultrasound provide direct visualization of the nerve and surrounding abnormalities. Bony abnormalities contributing to nerve compression are best assessed by radiographs and CT. Knowledge of the anatomy, the etiology, typical clinical findings, and imaging features of peripheral neuropathies affecting the peripheral nerves of the foot and ankle will allow for a more confident diagnosis.

Assessing diagnostic accuracy and the clinical value of positron emission tomography imaging in patients with solitary pulmonary nodules (SNAP)

BACKGROUND

Diagnostic tests, particularly diagnostic imaging modalities such as computed tomography (CT) and positron emission tomography (PET), have the potential to make important contributions to improved patient care and medical decision making. The expense of these tests is justified to the extent that they improve diagnostic and treatment decisions, and ultimately health outcomes. Clinical studies evaluating the accuracy of diagnostic tests and assessing their influence on decision making are essential to setting health policy and directing patient care.

PURPOSE

We present the design and participant baseline characteristics of the Department of Veterans Affairs Cooperative Study 027 (Prospective Study of the Diagnostic Accuracy of 18F-Fluorodeoxyglucose (FDG) - Positron Emission Tomography (PET) Imaging in the Management of Patients with Solitary Pulmonary Nodules (SNAP).

METHODS

SNAP is a prospective, multi-site diagnostic trial to evaluate the efficacy of PET and CT for characterizing solitary pulmonary nodules. The study incorporated an assessment of the impact of these imaging modalities on clinical decision making.

RESULTS

Between January 1999 and June 2001, 10 SNAP sites enrolled 532 participants with a mean age of 66 years (SD +/- 11.3), of whom 97.3% were male. A history of smoking was claimed by 93.6% of participants, with 45.7% of all participants smoking at time of enrollment. Those still smoking had an average exposure of 56.8 pack-years, while those who had quit smoking prior to enrollment had an exposure of 58.1 pack-years.

LIMITATIONS

The study design reduced most common biases, but some degree of selection bias and verification bias remained. We sought to minimize verification bias by use of a dual reference standard.

CONCLUSION

SNAP is a diagnostic test study that was designed to minimize bias and to assess a test's impact on clinical decision making, providing the kind of information most needed by clinicians and health policy makers.

Régression du névrome de Morton après infiltration de corticostéroïdes

Morton neuroma is a non neoplastic lesion corresponding to perineural fibrosis encircling the common interdigital plantar nerve. Several therapeutic approaches are possible: conservative treatment or surgery. We report a case treated by local steroid injection where follow-up MR showed near complete regression of the lesion. Although local injection of steroid is a classical treatment, it is the first time to our knowledge that resolution or such a striking diminution of size is reported after infiltration.

Seizure disorders: functional MR imaging for diagnostic evaluation and surgical treatment--prospective study

PURPOSE

To prospectively evaluate effect of functional magnetic resonance (MR) imaging on diagnostic work-up and treatment planning in patients with seizure disorders who are candidates for surgical treatment.

MATERIALS AND METHODS

Institutional review board approval was obtained; informed consent was obtained either from the patient or the parent or guardian in all patients. This study was conducted with Health Insurance Portability and Accountability Act compliance. Sixty consecutively enrolled patients (33 males, 27 females; mean age, 15.8 years +/- 8.7 [standard deviation]; range, 6.8-44.2 years) were prospectively examined. Forty-five (75%) patients were right handed, nine (15%) were left handed, and six (10%) had indeterminate hand dominance. Prospective questionnaires were used to evaluate diagnostic work-up, counseling, and treatment plans of the seizure team before and after functional MR imaging. Confidence level scales were used to determine effect of functional MR imaging on diagnostic and therapeutic thinking. Paired t test and 95% confidence interval analyses were performed.

RESULTS

In 53 patients, language mapping was performed; in 33, motor mapping; and in seven, visual mapping. The study revealed change in anatomic location or lateralization of language-receptive (Wernicke) (28% of patients) and language-expressive (Broca) (21% of patients) areas. Statistically significant increases were found in confidence levels after functional MR imaging in regard to motor and visual cortical function evaluation. In 35 (58%) of 60 patients, the seizure team thought that functional MR imaging results altered patient and family counseling. In 38 (63%) of 60 patients, functional MR imaging results helped to avoid further studies, including Wada test. In 31 (52%) and 25 (42%) of 60 patients, intraoperative mapping and surgical plans, respectively, were altered because of functional MR imaging results. In five (8%) patients, two-stage surgery with extra-operative direct electrical stimulation mapping was averted, and resection was accomplished in one stage. In four (7%) patients, extent of surgical resection was altered because eloquent areas were identified close to seizure focus.

CONCLUSION

Functional MR imaging results influenced diagnostic and therapeutic decision making of the seizure team; results indicated language dominance changed, confidence level in identification of critical brain function areas increased, patient and family counseling were altered, and intraoperative mapping and surgical approach were altered.

Nerves in a pinch: imaging of nerve compression syndromes

Nerve compression is a common entity that can result in considerable disability. Early diagnosis is important to institute prompt treatment and to minimize potential injury. Although the appropriate diagnosis is often determined by clinical examination, the diagnosis may be more difficult when the presentation is atypical, or when anatomic and technical limitations intervene. In these instances, imaging can have an important role in helping to define the site and etiology of nerve compression or in establishing an alternative diagnosis. MR imaging and ultrasound provide direct visualization of the nerve and surrounding abnormalities. For both modalities, the use of high-resolution techniques is important. Bony abnormalities contributing to nerve compression are best assessed by radiographs or CT. For the radiologist, knowledge of the anatomy of the fibro-osseous tunnels, familiarity with the causes of nerve compression, and an understanding of specialized imaging techniques are important for successful diagnosis of nerve compression.

Morton's neuroma

Morton's neuroma is a common problem. Progress has been made in the understanding of this frequent problem since Morton's original description and treatment. Today, we accept a failure rate of 15% to 20%, even in the best of series. We must ask ourselves if this is good enough. What can we do to achieve an acceptable failure of 5% or less? How can we improve? Only through an honest analysis and discussion can we improve the care that we deliver.

Morton neuroma: MR imaging in prone, supine, and upright weight-bearing body positions

PURPOSE

To assess the effect of prone, supine, and upright weight-bearing body positions on visibility, position, shape, and size of Morton neuroma during magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Eighteen patients with 20 Morton neuromas underwent MR imaging of the forefoot in prone (plantar flexion of the foot), supine (dorsiflexion of the foot), and upright weight-bearing positions. Visibility (3 = good, 2 = moderate, 1 = poor), position relative to the metatarsal bone, shape, and transverse diameter of Morton neuroma were assessed on transverse T1-weighted MR images. Associations between different body positions and variables of interest were calculated with Wilcoxon signed rank test, chi2 test, and paired Student t test.

RESULTS

In the prone position, visibility of all 20 Morton neuromas was rated with a score of 3; visibility in the supine and weight-bearing positions was inferior (mean score, 2.4). All 20 (100%) Morton neuromas changed their position relative to the metatarsal bone between prone and supine and between prone and weight-bearing positions. When compared with the prone position, there was a difference in the shape of all 20 Morton neuromas in the weight-bearing position (P <.001). Between prone (mean transverse diameter of Morton neuroma, 8 mm) and supine (mean transverse diameter of Morton neuroma, 6 mm) positions, the transverse diameter of Morton neuroma significantly decreased by 2 mm (P =.03); between prone and weight-bearing positions, the decrease of the mean transverse diameter was also significant (difference, 2 mm; P =.03).

CONCLUSION

Morton neuroma appears significantly different during MR imaging in prone, supine, or weight-bearing positions. The transverse diameter of Morton neuroma is significantly larger on images obtained in the prone position than it is on images obtained in the supine and upright weight-bearing positions. Visibility of Morton neuroma is best on MR images obtained in the prone position.

Bone marrow abnormalities of foot and ankle: STIR versus T1-weighted contrast-enhanced fat-suppressed spin-echo MR imaging

PURPOSE

To compare short inversion time inversion-recovery (STIR) and T1-weighted contrast material-enhanced fat-suppressed spin-echo magnetic resonance (MR) sequences for depiction of bone marrow abnormalities of the foot and ankle.

MATERIALS AND METHODS

Fifty-one consecutive patients with bone marrow abnormalities depicted on turbo STIR images were examined with additional T1-weighted contrast-enhanced (0.1 mmol/kg gadopentetate dimeglumine) MR imaging with fat suppression. Volume and signal difference-to-noise ratio (SDNR) were measured. An additional qualitative analysis was performed by two experienced musculoskeletal radiologists to correlate the presence or absence of ill-defined edema-like zones, well-defined zones, and cystlike zones. Diagnoses determined with MR findings with each sequence were compared with the results of a review panel. Correlation coefficients (r(2)) and paired t tests were calculated for all measurements. Agreement percentages and kappa values were calculated for inter- and intraobserver reproducibility.

RESULTS

Regarding volume of bone marrow abnormalities, a high correlation (r(2) = 0.98) of both sequences was found. SDNR was substantially higher on T1-weighted contrast-enhanced images than on STIR images (mean, 125.9 vs 95.4; P <.001). The qualitative analysis demonstrated identical imaging patterns with both sequences in 96% (79 of 82, kappa = 0.38) of ill-defined zones, in 88% (72 of 82, kappa = 0.76) of well-defined zones, and in 98% (80 of 82, kappa = 0.84) of cystlike zones. Interobserver reproducibility of the three imaging patterns was similar for both sequences. The kappa values for these three zones with STIR sequence were 0.55, 0.68, and 0.69, and those for the T1-weighted contrast-enhanced MR sequence were 0.49, 0.73, and 0.58, respectively. Diagnoses determined with MR findings were equal with both sequences in 94% (80 of 85) of involved bones.

CONCLUSION

STIR images and T1-weighted contrast-enhanced fat-suppressed MR images demonstrate almost identical imaging patterns, and diagnoses determined with these findings show little difference.