Imaging modalities for non-acute pathologies of the foot and ankle.

Chronic foot and ankle pain, in contrast to acute traumatic injuries, presents a diagnostic challenge due to its diverse underlying causes. Accurate diagnosis often necessitates the utilization of various imaging modalities, emphasizing the importance of selecting the most appropriate one. The intricate structure of the foot, composed of multiple bones and supported by soft tissues like ligaments and plantar fascia, gives rise to a spectrum of mechanical disorders, including stress fractures, plantar fasciitis, Morton's neuroma, and more. In addition to mechanical issues, non-acute abnormalities encompass inflammatory diseases affecting tendons and joints, benign tumors, tumor-like lesions, vascular abnormalities, and others. This article reviews the indispensable role of imaging in the assessment of these conditions, with a focus on plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine studies, tailored to the specific clinical presentation. By providing insights into the selection and interpretation of imaging modalities, this article aims to assist clinicians in achieving accurate diagnoses and optimizing patient care for nonacute foot and ankle pathologies.

Imaging of calcific tendinopathy: natural history, migration patterns, pitfalls, and management: a review.

Calcific tendinopathy is characterized by the deposition of calcium hydroxyapatite crystals in various tendons of the body. Terms like calcium tendinitis, tendinosis, and tendinopathy are used interchangeably. Calcific tendinopathy is a common and well-documented ailment in the literature. Although common, the natural history, aetiology, and progression of calcific tendinitis are poorly understood. The treatment options include conservative and interventional measures. However, these measures cannot be applied as a blanket and are often tailored depending on the stage/phase of the disease. Out of the recognized stages of the disease, the resorptive stage causes the utmost symptoms when the calcium is rather soft and unstable. During this stage, the calcium may migrate beyond expected resorption and get deposited in the adjacent tissues contiguous with the calcium focus. The common destinations include bursal migration, intraosseous migration, muscular migration, and other less common migration sites. Such atypical presentations can lead to dilemmas in the diagnosis, prolongation of the diagnostic pathway, unwarranted apprehension, and treatment delay. Radiologists' role in this situation is to correctly recognize the imaging findings of atypical presentations of calcific tendinopathy and prevent unnecessary diagnostic and interventional studies. In this review article, we describe the pathogenic pathway and natural history of calcific tendinopathy from a radiologist's perspective and discuss different migratory patterns of calcium in calcific tendinopathy not only around the shoulder but also in other areas of the body on different imaging modalities. We also show a few examples of mimics and pitfalls on imaging. Finally, we discuss the appropriate management option of this condition.

Non-neoplastic pathologies mimicking sarcoma - Experience from a tertiary referral centre multidisciplinary team.

OBJECTIVE: Distinguishing non-neoplastic tumour-mimicking pathologies from bone and soft tissue tumours is one of the fundamental aims of a tertiary centre sarcoma multidisciplinary team (MDT) service. In this study, we aim to analyse the incidence of non-neoplastic lesions referred to a tertiary referral service as suspected sarcoma, and to analyse the spectrum of conditions comprising these tumour-mimicking pathologies. MATERIALS AND METHODS: We conducted a retrospective observational study compiling the biopsy-proven non-neoplastic outcomes of suspected sarcoma cases referred to our MDT in the last year. We identified all referrals made to our service between 1st January 2020 and 31st December 2020 and compiled their histological diagnoses. RESULTS: A total of 976 new cases were referred to our MDT as suspected sarcoma in one year. Of these referrals, 8.6% (84/976) received a biopsy-proven outcome of non-neoplastic pathology. These non-neoplastic outcomes were categorised into the following types of pathology: 32.1% vascular, 31.0% inflammatory, 14.3% traumatic, 6.0% degenerative, 6.0% idiopathic, 4.8% infective, 3.6% metabolic, 1.2% autoimmune, and 1.2% genetic. CONCLUSION: A significant proportion of pathologies referred to a tertiary centre sarcoma MDT are non-neoplastic in nature. These lesions are made up of a range of pathologies, with vascular and inflammatory conditions being the most common. Our study, the first of its kind, offers clinicians an insight into tumour-mimicking pathologies encountered by a tertiary centre.

Nerve Entrapment in Ankle and Foot: Ultrasound Imaging.

Peripheral nerve entrapment of the ankle and foot is relatively uncommon and often underdiagnosed because electrophysiologic studies may not contribute to the diagnosis. Anatomy of the peripheral nerves is variable and complex, and along with a comprehensive physical examination, a thorough understanding of the applied anatomy is essential. Several studies have helped identify specific areas in which nerves are commonly compressed. Identified secondary causes of nerve compression include previous trauma, osteophytes, ganglion cysts, edema, accessory muscles, tenosynovitis, vascular lesions, and a primary nerve tumor. Imaging plays a key role in identifying primary and secondary causes of nerve entrapment, specifically ultrasound (US) and magnetic resonance imaging. US is a dynamic imaging modality that is cost effective and offers excellent resolution. Symptoms of nerve entrapment may mimic other common foot and ankle conditions such as plantar fasciitis.

Protection of the Proximal Articular Cartilage During Percutaneous Thermal Ablation of Acetabular Metastasis Using Temperature Monitoring.

OBJECTIVE: To review our initial experience in acetabular cartilage protection from thermal injury with temperature monitoring during percutaneous image-guided tumor thermal ablation. MATERIALS AND METHODS: Between June 2015 and December 2016, three consecutive oncologic patients (mean age 58 years; range 48-67 years) with acetabular bone metastasis underwent percutaneous image-guided thermal ablation procedures along with hip joint cartilage thermal monitoring. Due to the close proximity of the metastatic lesion to the acetabular articular cartilage, a thermosensor device was placed under CT and fluoroscopic guidance near the acetabular roof and next to the ablation zone in order to monitor the local temperature around the articular cartilage. Stand-alone thermal ablation (n = 1) and combined thermal ablation with cementoplasty (n = 2) were performed to optimize local palliation or disease control. Clinical and radiological outcomes at follow-up were assessed. RESULTS: Three acetabular metastatic lesions were treated with thermal ablation, and temperature monitoring of the acetabular articular cartilage was conducted during the ablation procedure. Mean size of lesions was 1.6 cm (range 1.5-2 cm). Technical success was achieved in all cases (100%) without any immediate complications. No hip cartilage damage occurred clinically and radiologically. Good palliation and local disease control were achieved in two cases, and in the other case, there was local recurrence and distant progression of hip metastatic disease after 7 months of follow-up. CONCLUSION: Temperature monitoring of the articular cartilage during percutaneous image-guided thermal ablation appears technically feasible with good short-term efficacy in a complex patient subset. Further studies are warranted to confirm these promising initial results.

Ultrasound-Guided Biopsies of Bone Lesions Without Cortical Disruption Using Fusion Imaging and Needle Tracking: Proof of Concept.

OBJECTIVE: To assess the technical feasibility and safety of combined fusion imaging and needle tracking under ultrasound guidance to target bone lesions without cortical disruption. MATERIALS AND METHODS: Between January 2016 and March 2016, seven patients underwent US-guided biopsy of bone lesions without cortical disruption. Targeted bone lesions were measuring more than 1.5 cm with a thin cortex, a trans-osseous pathway not exceeding 2 cm and without any adjacent vulnerable structures. First three procedures were performed in the CT suite to aid the needle tracking where necessary (group 1), the remaining four procedures were performed in the US suite (group 2). In group 1, deviation from the real position of the bone trocar (estimated on CT) was compared to the virtual position (estimated on the fusion CT-US images). In both group, procedure data and histopathological results were collected, and compared to the suspected diagnosis and follow-up. RESULTS: Mean procedure duration was 44 min. Total number of synchronisation points for combined fusion imaging were 3.3 on average. In group 1, mean deviation between the virtual and real CT coordinates was 5.3 mm on average. All biopsies yielded adequate quality analysable bone sample. Histopathological analysis revealed malignancy in three cases, non-specific inflammation in two cases, and normal bone in two cases. The four benign results were confirmed as true negative results. There were no immediate or post-procedural complications. CONCLUSION: The use of combined fusion imaging and needle tracking ultrasound guidance to target bone lesions without cortical disruption seems technically feasible, provided the patient and lesion selection is appropriate.