Magnetic resonance imaging has become the first choice imaging method for the evaluation of the joints due to its exceptional tissue differentiation, high resolution, multiplanar images and kinematics studies. The knee is probably the most common joint evaluated by magnetic resonance imaging and the knowledge of anatomy, physiology and imaging features is essential for an accurate interpretation of these studies. However, anatomical structures that are only observed sporadically, normal variants and artifacts may sometimes make it difficult to interpret these examinations. The purpose of this article is to review the most frequent pitfalls of magnetic resonance imaging of the knee, discuss their causes and how to avoid them.

Keywords: Magnetic resonance imaging. Knee. Pitfalls. Errors. Pseudolesions.

Human mistakes are an important source of errors in radiotherapy and may occur at every step of the radiotherapeutic planning and treatment. To reduce this level of uncertainties, several specialized organizations have recommended a comprehensive quality assurance program. In Brazil, the requirement for these programs has been strongly stressed, and most radiotherapy services have pursued this goal regarding radiation units and dosimetry equipment, as well as the verification of the calculations of the patient's dose and the revision of the plan charts. As a contribution to the improvement of quality control, we present some recommendations to avoid failure of treatment due to error in the delivered dose, such as redundant check of the manual or computer calculations, weekly check of the total dose for each patient, and prevention of inadvertent access to any safety system of the equipment by any staff member that is only supposed to operate the machine. Moreover, the use of a computerized treatment record and verification system should be considered in order to eliminate errors due to incorrect selection of the treatment parameters, in a daily basis. We report four radioactive incidents with patient injuries occurred throughout the world and some gross errors of dose.

Keywords: Radiotherapy. Treatment. Dose errors. Quality assurance.

The present study was aimed at analyzing civil liability for medical errors specifically for a radiologist’s errors in the mammographic diagnosis of breast cancer. As examples, Court decisions were analyzed with the aim of showing the understanding of the Brazilian Courts of Law, among them the Supreme Federal Court that is responsible for reviewing, on appeal, judicial decisions affronting the Brazilian Constitution, as well as the Superior Court of Justice, that is competent to judge on appeals against decisions violating Federal Laws. The reviewed material demonstrates the Courts’ view on the subject discussed on the present article, describing the consequences of radiologists’ and radiological centers’ errors in the sphere of the civil law that establishes monetary indemnity as a consequence of the existence of civil liability. That is to say that the duty to indemnify arises from the testifying of the existence of civil liability. Thus, once the civil liability is removed, the duty to indemnify comes to an end. Indemnity should not be confused with civil liability; the latter is the foundation of the former.

Keywords: Medical error; Mammography, Breast cancer; Civil liability.

OBJECTIVE: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. MATERIALS AND METHODS: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5-mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. RESULTS: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. CONCLUSION: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used.

Keywords: Frame cranial radiosurgery; Frameless cranial radiosurgery; IGRT; Setup errors; Residual errors; Phantoms, imaging.

Vanishing bone metastasis (pseudopathological vertebral body enhancement) is a pitfall in the interpretation of contrast-enhanced computed tomography (CT) scans of patients with thoracic vein obstruction, mainly in the superior vena cava and brachiocephalic veins, typically being related to thrombosis due to malignant tumors. On the basis of the CT findings, pseudopathological vertebral body enhancement can be misdiagnosed as sclerotic bone metastasis, leading to unnecessary treatment. Although not rare, pseudopathological vertebral body enhancement is usually underdiagnosed by radiologists. The aim of this study is to review the pathophysiology of this phenomenon, illustrating the most common collateral venous pathways in thoracic vein obstruction and making the correlation with the CT findings.

Keywords: Neoplasm metastasis/physiopathology; Bone and bones/diagnostic imaging; Tomography, X-ray computed; Diagnostic errors; Venous thrombosis; Collateral circulation.

Inherited neurometabolic disorders represent a diagnostic challenge, and an efficient classification system is needed in order to improve the understanding of these diseases. Although they constitute a group of rare diseases, they have a collective incidence of at least one case per 1,000 live births. Some inherited neurometabolic disorders are treatable. The clinical and radiological presentations are variable and sometimes overlap, depending on the stage of the disease. Therefore, a number of classification systems have been devised, some of which are difficult to apply in practice. The aim of this study was to illustrate a classification system for inherited neurometabolic disorders, based exclusively on radiological findings. This was a retrospective study of imaging examinations of the central nervous system, particularly of children, performed in a network of hospitals. All of the cases were studied by multidetector computed tomography, magnetic resonance imaging, or both, the images having been obtained by two neuroradiologists. We included only cases in which a definitive diagnosis was made. The classification system separates the relevant radiological findings into 10 categories. All of the cases studied presented at least one of those findings. In most of the cases, more than one finding was observed, which increased specificity and narrowed the differential diagnosis. Data from the literature and from this study demonstrate that it is possible to classify inherited neurometabolic disorders by their radiological aspects, which favors a definitive diagnosis.

Keywords: Metabolism, inborn errors/classification; Brain diseases, metabolic, inborn/classification; Diagnostic imaging/trends; Computed tomography; Magnetic resonance imaging.