Andrea Donovan

MR Imaging of Entrapment Neuropathies of the Lower Extremity Part 2. The Knee, Leg, Ankle, and Foot'

Entrapment neuropathies of the knee, leg, ankle, and foot are often underdiagnosed, as the results of clinical examination and electrophysiologic evaluation are not always reliable. The causes of most entrapment neuropathies in the lower extremity may be divided into two major categories: (a) mechanical causes, which occur at fibrous or fibro-osseous tunnels, and (b) dynamic causes related to nerve injury during specific limb positioning. Magnetic resonance (MR) imaging, including high-resolution MR neurography, allows detailed evaluation of the course and morphology of peripheral nerves, as well as accurate delineation of surrounding soft-tissue and osseous structures that may contribute to nerve entrapment. Familiarity with the normal MR imaging anatomy of the nerves in the knee, leg, ankle, and foot is essential for accurate assessment of the presence of peripheral entrapment syndromes. Common entrapment neuropathies in the knee, leg, ankle, and foot include those of the common peroneal nerve, deep peroneal nerve, superficial peroneal nerve, tibial nerve and its branches, and sural nerve.

Views of Radiology Program Directors on the Role of Mentorship in the Training of Radiology Residents

OBJECTIVE The successful mentoring of resident physicians has been linked to several beneficial outcomes for trainees including increased research productivity, improved career satisfaction, and retention in academics. Female residents may have greater difficulty establishing mentoring relationships than male residents. The purpose of this study was to assess the attitudes of radiology residency program directors toward the subject of mentorship, to determine the prevalence of formal mentoring programs, and to evaluate several issues specifically pertaining to the mentoring of female residents. MATERIALS AND METHODS An anonymous, voluntary survey was sent to 156 members of the Association of Program Directors in Radiology. The survey assessed views on mentorship during residency training, the potential role of mentorship in resident career development, and the prevalence of mentorship programs in residency programs. Subanalyses evaluated survey responses according to program director sex. RESULTS Seventy program directors (45%) responded to the survey. The majority of respondents (85%) agreed it is important for residents to have mentors, but only 52% thought that current residents had identified mentors. Compared with male program directors, female program directors differed in their views on the role of mentorship and of the importance of female resident access to female mentors. CONCLUSION Program directors consider mentoring relationships to be an important resource for resident professional development and a potential resource to increase the proportion of residents pursuing academic careers and positions of leadership. Female residents may have specific mentoring needs that should be explored with further study.

MRI of ankle and lateral hindfoot impingement syndromes.

OBJECTIVE The objective of this article is to review the pathophysiology and clinical presentation of impingement syndromes at the ankle joint (anterolateral, anterior, anteromedial, posteromedial, and posterior) and the role of MRI in evaluating impingement at the ankle joint and at extraarticular locations, lateral to the ankle joint (talocalcaneal and calcaneofibular). CONCLUSION MRI is valuable in assessing both osseous and soft-tissue abnormalities associated with impingement syndromes.

Use of MR Imaging in Diagnosing Diabetes-related Pedal Osteomyelitis

The clinical diagnosis of diabetes-related osteomyelitis relies on the identification and characterization of an associated foot ulcer, a method that is often unreliable. Magnetic resonance (MR) imaging is the modality of choice for imaging evaluation of pedal osteomyelitis. Because MR imaging allows the extent of osseous and soft-tissue infection to be mapped preoperatively, its use may limit the extent of resection. At MR imaging, the simplest method to determine whether osteomyelitis is present is to follow the path of an ulcer or sinus tract to the bone and evaluate the signal intensity of the bone marrow. Combined findings of low signal intensity in marrow on T1-weighted images, high signal intensity in marrow on T2-weighted images, and marrow enhancement after the administration of contrast material are indicative of osteomyelitis. Secondary signs of osteomyelitis include periosteal reaction, a subtending skin ulcer, sinus tract, cellulitis, abscess, and a foreign body. The location of a marrow abnormality is a key distinguishing feature of osteomyelitis: Whereas neuroarthropathy most commonly affects the tarsometatarsal and metatarsophalangeal joints, osteomyelitis occurs distal to the tarsometatarsal joint, in the calcaneus and malleoli. In the midfoot, secondary signs of infection help differentiate between neuroarthropathy and a superimposed infection.

Extraarticular Lateral Hindfoot Impingement With Posterior Tibial Tendon Tear: MRI Correlation

OBJECTIVE Posterior tibial tendon dysfunction with secondary hindfoot valgus can lead to painful extraarticular, lateral talocalcaneal, and subfibular impingements, often necessitating surgical intervention. The purpose of this study was to correlate findings of lateral hindfoot impingement with grading of posterior tibial tendon tears and severity of hindfoot valgus on MRI. MATERIALS AND METHODS MR images from 75 patients (45 women and 30 men) with MRI evidence of posterior tibial tendon tears were evaluated for grade of posterior tibial tendon tear, hindfoot valgus angle, osseous contact or opposing marrow signal changes at the talus-calcaneus or fibula-calcaneus, peroneal tendon subluxation-dislocation, and presence of lateral malleolar bursa. Statistical analyses were performed using Cochran-Armitage, Fishers exact, and Mann-Whitney tests. RESULTS Twenty-eight cases (37%) of lateral hindfoot impingement were identified, including six talocalcaneal, eight subfibular, and 14 talocalcaneal-subfibular impingements. The prevalence of impingement was significantly increased with greater MRI hindfoot valgus angle (p < 0.001). The prevalence of talocalcaneal-subfibular impingement significantly increased with grading of posterior tibial tendon tear (p = 0.018). Peroneal tendon subluxation was present only with advanced hindfoot valgus (p = 0.010) and impingement (p = 0.004). There was no significant association between the presence of lateral malleolar bursa and hindfoot valgus severity. CONCLUSION Extraarticular lateral hindfoot impingement is associated with advanced posterior tibial tendon tears and increased MRI hindfoot valgus angle. Peroneal tendon subluxation likely represents an end stage of lateral impingement in patients with posterior tibial tendon dysfunction.

Current Concepts in Imaging Diabetic Pedal Osteomyelitis

Diabetic pedal osteomyelitis is primarily a manifestation of vascular insufficiency with resultant tissue ischemia, neuropathy, and infection. Nearly all cases of pedal osteomyelitis arise from a contiguous ulcer and soft tissue infection. MR imaging is the modality of choice to assess for the presence of osteomyelitis and associated soft tissue complications, to guide patient management, and to aid in limited limb resection.

Mentorship in postgraduate training programmes: views of Canadian programme directors.

Objectives  Many academic training programmes have developed mentorship programmes for postgraduate doctors in training, but little is known about the factors that influence their establishment.

Radiology Residents as Teachers : Current Status of Teaching Skills Training in United States Residency Programs

RATIONALE AND OBJECTIVES Radiology residents often teach medical students and other residents. Workshops developed with the goal of improving resident teaching skills are becoming increasingly common in various fields of medicine. The purpose of this study was to determine the prevalence and structure of resident-teacher training opportunities within radiology programs in the United States. METHOD AND MATERIALS Program directors with membership in the Association of Program Directors in Radiology (APDR) were surveyed to determine views on a panel of topics related to resident-teacher training programs. RESULTS A total of 114 (56%) of 205 APDR members completed an online survey. Approximately one-third (32%) stated that their program provided instruction to residents on teaching skills. The majority of these programs (72%) were established within the last 5 years. Residents provided teaching to medical students (94%) and radiology residents (90%). The vast majority of program directors agreed that it is important for residents to teach (98%) and that these teaching experiences helped residents become better radiologists (85%). Ninety-four percent of program directors felt that the teaching skills of their residents could be improved, and 85% felt that residents would benefit from instruction on teaching methods. Only one-third of program directors felt their program adequately recognized teaching provided by residents. CONCLUSION Program directors identified residents as being active contributors to teaching in most programs. Although teaching was viewed as an important skill to develop, few programs had instituted a resident-teacher curriculum. Program directors felt that residents would benefit from structured training to enhance teaching skills. Future studies are needed to determine how best to provide teaching skills training for radiology trainees.

Plantar Tendons of the Foot: MR Imaging and US

Tendon disorders along the plantar aspect of the foot may lead to significant symptoms but are often clinically misdiagnosed. Familiarity with the normal anatomy of the plantar tendons and its appearance at magnetic resonance (MR) imaging and ultrasonography (US) is essential for recognizing plantar tendon disorders. At MR imaging, the course of the plantar tendons is optimally visualized with dedicated imaging of the midfoot and forefoot. This imaging should include short-axis images obtained perpendicular to the long axis of the metatarsal shafts, which allows true cross-sectional evaluation of the plantar tendons. Normal plantar tendons appear as low-signal-intensity structures with all MR sequences. At US, accurate evaluation of the tendons requires that the ultrasound beam be perpendicular to the tendon. The normal tendon appears as a compact linear band of echogenic tissue that contains a fine, mixed hypoechoic and hyperechoic internal fibrillar pattern. Tendon injuries can be grouped into six major categories: tendinosis, peritendinosis, tenosynovitis, entrapment, rupture, and instability (subluxation or dislocation) and can be well assessed with both MR imaging and US. The radiologist plays an important role in the diagnosis of plantar tendon disorders, and recognizing their imaging appearances at MR imaging and US is essential.

Correlation of Computed Tomography Imaging Features With Pain Response in Patients With Spine Metastases After Radiation Therapy

PURPOSE To correlate computed tomography (CT) imaging features of spinal metastases with pain relief after radiotherapy (RT). METHODS AND MATERIALS Thirty-three patients receiving computed tomography (CT)-simulated RT for spinal metastases in an outpatient palliative RT clinic from January 2007 to October 2008 were retrospectively reviewed. Forty spinal metastases were evaluated. Pain response was rated using the International Bone Metastases Consensus Working Party endpoints. Three musculoskeletal radiologists and two orthopaedic surgeons evaluated CT features, including osseous and soft tissue tumor extent, presence of a pathologic fracture, severity of vertebral height loss, and presence of kyphosis. RESULTS The mean patient age was 69 years; 24 were men and 9 were women. The mean worst pain score was 7/10, and the mean total daily oral morphine equivalent was 77.3 mg. Treatment doses included 8 Gy in one fraction (22/33), 20 Gy in five fractions (10/33), and 20 Gy in eight fractions (1/33). The CT imaging appearance of spinal metastases included vertebral body involvement (40/40), pedicle involvement (23/40), and lamina involvement (18/40). Soft tissue component (10/40) and nerve root compression (9/40) were less common. Pathologic fractures existed in 11/40 lesions, with resultant vertebral body height loss in 10/40 and kyphosis in 2/40 lesions. At months 1, 2, and 3 after RT, 18%, 69%, and 70% of patients experienced pain relief. Pain response was observed with various CT imaging features. CONCLUSIONS Pain response after RT did not differ in patients with and without pathologic fracture, kyphosis, or any other CT features related to extent of tumor involvement. All patients with painful spinal metastases may benefit from palliative RT.