Yu-Ching Lin

Imaging of Adult Flatfoot: Correlation of Radiographic Measurements With MRI

OBJECTIVE. The purpose of this study is to determine whether radiographic foot measurements can predict injury of the posterior tibial tendon (PTT) and the supporting structures of the medial longitudinal arch as diagnosed on MRI. MATERIALS AND METHODS. After institutional review board approval, 100 consecutive patients with radiographic and MRI examinations performed within a 2-month period were enrolled. Thirty-one patients had PTT dysfunction clinically, and 69 patients had other causes of ankle pain. Talonavicular uncoverage angle, incongruency angle, calcaneal pitch angle, Meary angle, cuneiform-to-fifth metatarsal height, and talar tilt were calculated on standing foot or ankle radiographs. MRI was used to assess for abnormalities of the PTT (tenosynovitis, tendinosis, and tear) and supporting structures of the medial longitudinal arch (spring ligament, deltoid ligament, and sinus tarsi). Statistical analysis was performed using the chi-square and Fisher exact tests for categoric variables; the Student t test was used for continuous variables. RESULTS. There was a statistically significant association of PTT tear with abnormal talonavicular uncoverage angle, calcaneal pitch angle, Meary angle, and cuneiform-to-fifth metatarsal height. PTT tendinosis and isolated tenosynovitis had a poor association with most radiologic measurements. If both calcaneal pitch and Meary angles were normal, no PTT tear was present. An abnormal calcaneal pitch angle had the best association with injury to the supporting medial longitudinal arch structures. CONCLUSION. Radiographic measurements, especially calcaneal pitch and Meary angles, can be useful in detecting PTT tears. Calcaneal pitch angle provides the best assessment of injury to the supporting structures of the medial longitudinal arch.

Reverse Halo Sign in Pulmonary Mucormyosis

### Learning Point for Clinicians Invasive pulmonary mucormycosis (PM) is a dreadful complication in immunosuppressed patients. Pulmonary mucormycosis is difficult to diagnose clinically and potential delay can occur while waiting for biopsy results. Computerized tomography is helpful in detecting the presence of PM with the help of typical radiological appearance resulting in early diagnosis and treatment. Reverse halo sign (RHS), also called the atoll sign, was described as a rim of consolidation surrounding a center of ground-glass opacity on computed tomography (CT).1,2 Although RHS was previously considered as non-specific sign for various disorders, recent study showed that it is a strong indicator of pulmonary mucormycosis (PM).2,3 We present a case of PM with typical imaging presentation on CT, which highlights the importance of RHS in predicting PM, especially in patients …

The Hindfoot Arch: What Role Does the Imager Play?

Flatfoot deformity is a common disorder of the foot and ankle and is caused by loss of the hindfoot arch. Radiologists and clinicians should be familiar with the anatomy and the imaging criteria used to assess injury to the supporting structures. Radiographs and computed tomography are most useful in characterizing the degree of osseous deformity and ultrasonography and magnetic resonance imaging are most useful in the evaluation of the supporting soft tissue structures. Treatment depends on the clinical symptoms and involves restoring the normal biomechanics of the hindfoot arch through strengthening exercises, foot/ankle orthotics, and surgery.

Bone tumor mimickers: A pictorial essay

Focal lesions in bone are very common and many of these lesions are not bone tumors. These bone tumor mimickers can include numerous normal anatomic variants and non-neoplastic processes. Many of these tumor mimickers can be left alone, while others can be due to a significant disease process. It is important for the radiologist and clinician to be aware of these bone tumor mimickers and understand the characteristic features which allow discrimination between them and true neoplasms in order to avoid unnecessary additional workup. Knowing which lesions to leave alone or which ones require workup can prevent misdiagnosis and reduce patient anxiety.

Bursal synovial chondromatosis formation following osteochondroma resection

Osteochondroma is a common tumor of the bone and can be complicated by adventitial bursa formation and malignant transformation of the cartilaginous cap. Synovial chondromatosis formation within these bursae is extremely rare and can be confused with malignant transformation of the osteochondroma cap to a chondrosarcoma. We describe a case of extra-articular synovial chondromatosis formation several years following osteochondroma resection. Cartilage nodule formation within the bursal synovial lining and proliferation of cartilage debris shed from the cartilaginous cap during surgery or biopsy are potential etiologies of this rare complication of osteochondromas.

Application of the World Health Organization Fracture Risk Assessment Tool to predict need for dual-energy X-ray absorptiometry scanning in postmenopausal women.

OBJECTIVE To evaluate the efficacy of the World Health Organization Fracture Risk Assessment Tool, excluding bone mineral density (pre-BMD FRAX), in identifying Taiwanese postmenopausal women needing dual-energy X-ray absorptiometry (DXA) examination for further treatment. MATERIALS AND METHODS The pre-BMD FRAX score was calculated for 231 postmenopausal women who participated in public health education workshops in the local Keelung community, Taiwan. DXA scanning and vertebral fracture assessment (VFA) were arranged for women classified as intermediate or high risk for fracture using the pre-BMD FRAX fracture probability. RESULTS Pre-BMD FRAX classified 26 women as intermediate risk and 37 as having high risk for fracture. Subsequent DXA scans for these 63 women showed that 36 were osteoporotic, 19 were osteopenic, and eight had normal bone density. Concurrent VFA revealed 25 spine factures in which 14 were osteoporotic, seven were osteopenic, and four had normal bone density. The efficacy of the pre-BMD FRAX score to identify those patients with low bone mass by DXA was 87.3% (55/63). When VFA was combined with BMD to identify those patients with high risk (osteopenia, osteoporosis, or spinal fracture), the efficacy of the pre-BMD score increased to 93.7% (59/63). According to the National Osteoporosis Foundation, the overall concordance between pre-BMD FRAX and BMD, expressed through the kappa index, was 0.967. Compared with the evaluation when BMD was used alone, there was a significant increase in efficacy in identifying women who need treatment using BMD plus VFA or FRAX plus BMD. Furthermore, the highest efficacy was achieved when FRAX with BMD and VFA was used. CONCLUSION The pre-BMD FRAX score not only efficiently predicts postmenopausal patients who are potentially at risk and might require treatment but also reduces unnecessary DXA use. Concurrent VFA during DXA use increases spine fracture detection. This improvement in diagnostic efficacy allows clinicians to provide the most appropriate therapeutic recommendation.

Foreign body venous transmigration to the heart.

### Learning Point for Clinicians Despite its rarity, foreign body lodging into the major peripheral vein due to trauma can travel to central vein and even to the heart. Progressive proximal movement of foreign body should alert clinicians of the possibility of foreign body migration in the vein. Foreign bodies migrating from the major vein to the heart are rare;1 moreover, it is exceptionally rare to capture and report their course from the vein to the heart through sequential imaging. Progressive proximal movement of foreign body should alert clinicians of the possibility of foreign body migration in the vein. We demonstrate through sequential plain radiographs and computed tomography (CT) imaging of the course of an intravenous foreign body travelling to the right ventricle secondary to trauma to the right upper arm. A 35-year-old metal worker presented to a rural hospital with piercing injury to his right upper arm from a piece of metal. Plain radiograph of the right …

MRI assessment of regional differences in phosphorus-31 metabolism and morphological abnormalities of the foot muscles in diabetes.

To assess differences in the phosphorus‐31 (31P) metabolism and morphology in multiple muscle regions in the forefoot of diabetic patients and normal subjects.

Myocardial crypts: role of modified two-chamber view.

### Learning Point for Clinicians The recognition of myocardial crypts is important to detect patients at high risk of pre-phenotypic hypertrophic cardiomyopathy. Through this presented case, we have illustrated the improved method of a modified two-chamber view across the infero-septum for optimal delineation of the myocardial crypts in both transthoracic echocardiography and cardiac magnetic resonance imaging. Myocardial crypts are blood-filled invaginations in the left ventricle, involving ≥50% of the myocardial thickness with total or near total obliteration during systole.1–3 The accurate identification of the myocardial crypts is important, as the presence of the myocardial crypts has been shown to be a pre-phenotypic marker for hypertrophic cardiomyopathy (HCM).1–4 Modified two-chamber views through the suspected sites of myocardial crypts, such as the infero-septum and right ventricular insertion site, have been suggested for …

Magnetic resonance imaging for acute hip pain in the emergency department

MRI is an excellent imaging modality for the evaluation of acute hip pain in the ED and provides accurate diagnosis; facilitating appropriate and timely management thereby can result in decreased cost and improved prognosis in these patients. In this article, we review the use of MRI for patients presenting with acute hip pain in the Emergency Department (ED), including MRI protocols, MRI features of common acute hip pathologies, pivotal differential diagnoses, and management options.