Diego F. Lemos

Imaging Appearances of the Sternum and Sternoclavicular Joints

The sternum and sternoclavicular joints--critical structures of the anterior chest wall--may be affected by various anatomic anomalies and pathologic processes, some of which require treatment. Pectus excavatum and pectus carinatum are common congenital anomalies that are usually benign but may warrant surgical treatment if they cause compression of vital internal structures. By contrast, developmental variants such as the sternal foramen are asymptomatic and do not require further evaluation or treatment. Arthritides of the sternoclavicular joint (osteoarthritis, septic arthritis, and seronegative arthropathies) are common and must be differentiated before an appropriate management method can be selected. The recognition of complications of sternotomy (eg, sternal dehiscence, secondary osteomyelitis) is critical to avoid life-threatening sequelae such as acute mediastinitis. Likewise, the detection of sternal fractures and sternoclavicular dislocations is important, especially where they impinge on vital structures. In addition, sternal malignancies (most commonly, metastases and chondrosarcoma) must be distinguished from benign neoplasms. To achieve accurate and timely diagnoses that facilitate appropriate treatment, radiologists must be familiar with the appearances of these normal anatomic variants and diseases of the sternum.

Intramural hematoma of the esophagus: a pictorial essay

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part of the spectrum of esophageal injuries which includes the more common Mallory–Weiss tear and Boerhaave’s syndrome. Acute retrosternal or epigastric pain is a common clinical feature, which can be accompanied by dysphagia, odynophagia, or hematemesis. An early differentiation from Mallory–Weiss tear, Boerhaave syndrome, ruptured aortic aneurysm, aortic dissection, acute myocardial infarction, or pulmonary pathology can be difficult. Computed tomography (CT) is the imaging modality of choice and characteristically reveals a concentric or eccentric thickening of the esophageal wall with well-defined borders and variable degree of obliteration of the lumen. Measurement of the attenuation values within the lesion will reveal blood density which varies according to the age of the hematoma. CT should be considered the preferred diagnostic technique, thereby facilitating proper clinical management. Early diagnosis is crucial as most patients maybe treated conservatively with good outcome.

The Diaphragmatic Crura and Retrocrural Space: Normal Imaging Appearance, Variants, and Pathologic Conditions

The retrocrural space (RCS) is a small triangular region within the most inferior posterior mediastinum bordered by the two diaphragmatic crura. Multiplanar imaging modalities such as computed tomography and magnetic resonance imaging allow evaluation of the RCS as part of routine examinations of the chest, abdomen, and spine. Normal structures within the retrocrural region include the aorta, nerves, the azygos and hemiazygos veins, the cisterna chyli with the thoracic duct, fat, and lymph nodes. There is a wide range of normal variants of the diaphragmatic crura and of structures within the RCS. Diverse pathologic processes can occur within this region, including benign tumors (lipoma, neurofibroma, lymphangioma), malignant tumors (sarcoma, neuroblastoma, metastases), vascular abnormalities (aortic aneurysm, hematoma, azygos and hemiazygos continuation of the inferior vena cava), and abscesses. An understanding of the anatomy, normal variants, and pathologic conditions of the diaphragmatic crura and retrocrural structures facilitates diagnosis of disease processes within this often overlooked anatomic compartment.

Association of two respiratory congenital anomalies: tracheal diverticulum and cystic adenomatoid malformation of the lung

Many associations of congenital anomalies of the respiratory system have been reported, but the combination of tracheal diverticulum and cystic adenomatoid malformation (CCAM) is unique. We present a patient with these two anomalies and analyze their embryological correlation.

Comprehensive Review of the Anatomy, Function, and Imaging of the Popliteus and Associated Pathologic Conditions

The popliteus is a relatively small but unique muscle of the knee. It is a component of the posterolateral corner of the knee and acts as a major stabilizer of the posterolateral knee. It is important to be aware of the normal magnetic resonance (MR) imaging appearance of the popliteus musculotendinous complex and its relation to other structures of the posterolateral corner for accurate diagnosis. It is also important to be aware of the pitfalls in imaging of the popliteus. Dysfunction of the popliteus is often underappreciated and is usually secondary to direct or indirect trauma. Injuries of the popliteus can be classified as first-, second-, or third-degree strains. Injuries of the popliteus are often associated with other posterolateral corner injuries. Pathologic conditions of the popliteus may be a clue to other injuries in the knee. The site and pattern of popliteus tear can be helpful to the orthopedic surgeon in deciding whether repair is warranted and determining the approach to surgery and has prognostic implications. Undiagnosed popliteus injuries can lead to poor functional results after knee reconstructive surgery. Inflammatory pathologic conditions of the popliteus may cause knee pain and can be diagnosed with MR imaging. The popliteus is an important component of the posterolateral corner that needs closer attention for optimal diagnosis and patient care.

Multifactorial pathological hip subluxation in neurofibromatosis type-1 (NF1) due to intra-articular plexiform neurofibroma, lumbar radiculopathy and neurofibromatous polyneuropathy.

Neurofibromatosis type-1 (NF1) is a multisystem disorder with very rare descriptions of hip instability. We report a case of a 37-year-old man with known NF1 and childhood-onset of left foot drop, who developed persistent left hip pain following a minor trauma. Physical examination revealed left-sided mild foot drop, hip abductor weakness, bilateral sensory loss in feet and an antalgic gait. Work-up revealed anterolateral subluxation of the left femoral head along with left hip plexiform neurofibroma (PN), dysplastic and degenerative changes, neurofibromatous neuropathy and chronic left L5 radiculopathy. Initial improvement after surgical resection of the PN was unsustained and followed by increasing pain and recurrent hip subluxation, prompting a total hip arthroplasty which resulted in marked improvement of symptoms. Our patient, unlike those in other reports, illustrates multiple aetiologies of hip dislocation in NF1 including local factors, lumbar radiculopathy and polyneuropathy, reinforcing the importance of a multidisciplinary approach in the management of such cases.