Incomplete Cord Syndromes: Clinical and Imaging Review.

The ability to localize the three spinal tracts (corticospinal tract, spinothalamic tract, and dorsal [posterior] columns) involved in incomplete spinal cord syndromes at cross-sectional imaging and knowledge of the classic clinical manifestations of the various syndromes enable optimized imaging evaluation and provide clinicians with information that aids in diagnosis and treatment. The requisite knowledge for localizing these tracts is outlined. The authors review the spinal cord anatomy, blood supply, and course of these tracts and describe the various associated syndromes: specifically, dorsal cord, ventral cord, central cord, Brown-Séquard, conus medullaris, and cauda equina syndromes. In addition, they describe the anatomic basis for the clinical manifestation of each syndrome and the relevant imaging features of the classic causes of these entities. Knowledge of the anatomy and clinical findings of the spinal cord is essential for examining and treating patients with cord abnormalities. ©RSNA, 2018.

Diagnosis-related Groups and Hospital Inpatient Federal Reimbursement.

To understand the complex system of reimbursement for health care services, it is helpful to have a working knowledge of the historic context of diagnosis-related groups (DRGs), as well as their utility and increasing relevance. Congress implemented the DRG system in 1983 in response to rapidly increasing health care costs. The DRG system was designed to control hospital reimbursements by replacing retrospective payments with prospective payments for hospital charges. This article explains how these payments are calculated. Every inpatient admission is classified into one of several hundred DRGs that are based on the diagnosis, complications, and comorbidities. The Centers for Medicare & Medicaid Services (CMS) assigns each DRG a weight that the CMS uses in conjunction with hospital-specific data to determine reimbursement. A population's DRGs represent the resources needed to treat the medical disorders of that population. Hospital administrators use this information to budget and plan for the future. The Affordable Care Act and other recent legislation affect medical reimbursement by altering the DRG system. Radiologic procedures in particular are affected. This legislation will give DRGs an even larger role in determining reimbursements in the coming years.

Vascular lesions of the orbit: more than meets the eye.

Vascular lesions of the orbit may be classified on the basis of their natural history, growth pattern, and histologic composition as capillary hemangiomas, venous vascular malformations, venous lymphatic malformations, arterial and arteriovenous lesions, or neoplasms. Most follow a characteristic pattern of clinical development and have one or more specific imaging features that allow diagnosis. Hemangiomas typically manifest at or soon after birth and subsequently involute. They are nonencapsulated, poorly circumscribed, often lobulated, and largely extraconal in location. Cavernous malformations are septate and well circumscribed, may exhibit progressive enhancement on delayed images, and do not involute. Orbital varices appear distended on images obtained with the patient prone or during the Valsalva maneuver. Venous lymphatic malformations show multiple fluid-fluid levels, enlarge during viral infections, and may manifest as chocolate-colored cysts after an acute hemorrhage. Arteriovenous malformations, fistulas, and aneurysms have typical angiographic features. Hemangiopericytomas arise from the paranasal sinuses and show early tumor blush and persistent staining on angiographic images. Hemangioblastomas appear as enhancing mural nodules with associated cysts and serpentine flow voids on magnetic resonance (MR) images. Choroidal hemangiomas and melanomas can be differentiated on the basis of their appearances on T2-weighted MR images. Patients with vascular orbital and ocular metastases commonly have a history of breast or lung primary tumors.

Denervation atrophy of motor cranial nerves.

Muscles undergoing denervation demonstrate a variety of imaging appearances in the various stages. It is incumbent on the radiologist to be aware of these changes so as not to interpret these muscles as harboring a tumor or being involved by an inflammatory process. Knowledge of cranial nerve anatomy and the muscles they innervate enables identification of denervation patterns that could implicate more than one nerve and directs the search for the causative lesion.

Horner's syndrome: clinical and radiographic evaluation.

Horner's syndrome (HS) occurs when there is interruption of the oculosympathetic pathway (OSP). This article reviews the anatomy of the OSP and clinical findings associated with lesions located at various positions along this pathway. The imaging findings of lesions associated with HS at various levels of the OSP, classified as preganglionic HS (first- and second-order neuron HS) or postganglionic HS (third-order neuron HS), are demonstrated.

Imaging the pregnant patient for nonobstetric conditions: algorithms and radiation dose considerations.

Use of diagnostic imaging studies for evaluation of pregnant patients with medical conditions not related to pregnancy poses a persistent and recurring dilemma. Although a theoretical risk of carcinogenesis exists, there are no known risks for development of congenital malformations or mental retardation in a fetus exposed to ionizing radiation at the levels typically used for diagnostic imaging. An understanding of the effects of ionizing radiation on the fetus at different gestational stages and the estimated exposure dose received by the fetus from various imaging modalities facilitates appropriate choices for diagnostic imaging of pregnant patients with nonobstetric conditions. Other aspects of imaging besides radiation (ie, contrast agents) also carry potential for fetal injury and must be taken into consideration. Imaging algorithms based on a review of the current literature have been developed for specific nonobstetric conditions: pulmonary embolism, acute appendicitis, urolithiasis, biliary disease, and trauma. Imaging modalities that do not use ionizing radiation (ie, ultrasonography and magnetic resonance imaging) are preferred for pregnant patients. If ionizing radiation is used, one must adhere to the principle of using a dose that is as low as reasonably achievable after a discussion of risks versus benefits with the patient.

Imaging of Intracranial and Orbital Complications of Sinusitis and Atypical Sinus Infection: What the Radiologist Needs to Know.

Sinusitis is a common disease. Complications, however, are less common and can be life threatening. Major complications occur from extension of disease into the orbit and intracranial compartment and often require emergent treatment with intravenous (IV) antibiotics or operative intervention. Immunocompromised patients with acute sinusitis are susceptible to atypical infections, such as invasive fungal sinusitis, which is a surgical emergency. Therefore, it is important to accurately and promptly identify potentional complications of acute sinusitis to ensure appropriate treatment and minimize negative outcomes. This article reviews the imaging features of a spectrum of complications associated with acute sinusitis and atypical infections.

Tired in the Reading Room: The Influence of Fatigue in Radiology.

Commonly conflated with sleepiness, fatigue is a distinct multidimensional condition with physical and mental effects. Fatigue in health care providers and any secondary effects on patient care are an important societal concern. As medical image interpretation is highly dependent on visual input, visual fatigue is of particular interest to radiologists. Humans analyze their surroundings with rapid eye movements called saccades, and fatigue decreases saccadic velocity. Oculomotor parameters may, therefore, be an objective and reproducible metric of fatigue and eye movement analysis can provide valuable insight into the etiology of fatigue-related error.

Positional ventricular tachycardia from a fractured mediport catheter with right ventricular migration--a case report.

The totally implantable catheter system has gained popularity as venous access when prolonged treatment is needed. Despite its frequent use, intravascular fracture and embolization of catheter fragments from implantable venous port-catheter systems present a rare but potentially life-threatening complication. Any implanted catheters should therefore be removed after completion of the treatment or the system's integrity should be monitored on a regular basis. This report illustrates such a case, which presented with ventricular tachycardia triggered by changes in body position from a fractured Mediport catheter with cardiac migration. A 34-year-old woman had a venous port catheter (Mediport) implanted into the right subclavian vein for neoadjuvant radio-chemotherapy for Hodgkin's lymphoma. Owing to the patient's difficult venous access the catheter was left in situ after treatment. Three years after insertion of the Mediport she presented with shortness of breath and palpitations when lying in the left lateral position. Physical examination revealed no abnormalities. An electrocardiogram was within normal rhythm. An outpatient Holter monitor revealed multiple episodes of nonsustained and sustained ventricular tachycardia triggered by lying in the left lateral position. A chest radiograph showed a normal location of the port-system, but the distal fragment of the catheter had embolized into the right ventricle. The embolized fragment was extracted with a gooseneck snare technique and the reservoir of the system was removed under local anesthesia without any complications. The patient was free of symptoms at 7 seven months follow-up.

Anatomy and embryology of the thyroid and parathyroid glands.

The thyroid and parathyroid glands are cervical endocrine glands responsible for metabolism-related functions. Radiologists are frequently asked to evaluate pathology related to the thyroid and parathyroid glands before planned surgical intervention. Knowledge of embryology and anatomy is fundamental in this region because rather complex underlying embryology produces substantial anatomic variation both in the thyroid bed and elsewhere in the neck and mediastinum.