OBJECTIVE: To evaluate the efficacy of hypnosis for management of claustrophobia in patients submitted to magnetic resonance imaging. MATERIALS AND METHODS: Twenty claustrophobic patients referred for magnetic resonance imaging under sedation were submitted to hypnosis using the Braid technique. The patients susceptible to hypnosis were submitted to magnetic resonance imaging under hypnotic trance without using sedative drugs. RESULTS: Out of the sample, 18 (90%) patients were susceptible to the technique. Of the 16 hypnotizable subjects who were submitted to magnetic resonance imaging, 15 (93.8%) could complete the examination under hypnotic trance, with no sign of claustrophobia and without need of sedative drugs. CONCLUSION: Hypnosis is an alternative to anesthetic sedation for claustrophobic patients who must undergo magnetic resonance imaging.

Keywords: Hypnosis, Claustrophobia, Magnetic resonance imaging

OBJECTIVE: The present study was aimed at describing uncommon presentations of intraosseous hemophilic pseudotumor in imaging diagnosis. MATERIALS AND METHODS: Retrospective study evaluating five hemophilic pseudotumors in bones of two patients with hemophilia A. Imaging findings were consensually evaluated by two musculoskeletal radiologists. Plain radiography, computed tomography and magnetic resonance imaging studies were analyzed. RESULTS: At contrast-enhanced computed tomography images, one of the lesions on the left thigh was visualized with heterogeneously enhanced solid areas. This finding was later confirmed by anatomopathological study. Another uncommon finding was the identification of a healthy bone portion interposed between two intraosseous pseudotumors in the humerus. And, finally, a femoral pseudotumor with extension towards soft tissues and transarticular extension, and consequential tibial and patellar involvement. CONCLUSION: The above described imaging findings are not frequently reported in cases of intraosseous pseudotumors in hemophilic patients. It is important that radiologists be aware of these more uncommon presentations of intraosseous pseudotumors.

Keywords: Magnetic resonance imaging, Pseudotumor, Hemophilia

The authors describe the case of a pregnant woman referred to the institution to be evaluated for an adnexal mass. Ultrasonography showed a voluminous solid-cystic lesion suggestive of ovarian neoplasm. Magnetic resonance imaging demonstrated that the lesion was located within the uterine serosa, suggesting the presence of a degenerated leiomyoma. A correct diagnosis of pelvic masses in pregnancy is essential for the definition of a therapeutic approach. Magnetic resonance imaging represents a relevant tool in the diagnosis of these abnormalities.

Keywords: Ultrasonography, Magnetic resonance imaging, Leiomyoma

OBJECTIVE: To develop an acceptance testing protocol for magnetic resonance imaging systems and to show which and how phantoms could be used to collect data. MATERIALS AND METHODS: The definition, procedure, analysis and the acceptation criteria were created for each of 15 selected tests. RESULTS: These tests allow the evaluation of technical specifications stated on the manufacturer's sales proposal and to establish reference values to be used in subsequent constancy tests. CONCLUSION: Future quality assurance programs in magnetic resonance imaging should consider employing tests similar or equal to the ones described in this paper.

Keywords: Magnetic resonance imaging, Quality control

Early magnetic resonance angiography techniques used flow-sensitive sequences to obtain contrast of the vascular structures. Three techniques are based on this approach: phase-contrast, time-of-flight and black blood techniques. However, these acquisition methods are time-consuming and more susceptible to movement artifacts, flow-related artifacts and signal loss due to stenotic lesions. They also present low sensitivity for slow flow detection. The use of paramagnetic contrast medium in magnetic resonance angiography studies provides a simple and quick way of obtaining vascular enhancement. Image contrast is based on vascular enhancement in opposition to background suppression. Important factors for the technical improvement of gadolinium-enhanced magnetic resonance angiography include modern techniques of central k-space ordering that are responsible for high image contrast, and implementation of appropriate timing injection. Gadolinium-enhanced magnetic resonance angiography is a useful diagnostic tool for investigation of anatomical anomalies, stenotic and occlusive disease, and surgical complications, particularly in patients with organ transplants. Gadolinium-enhanced magnetic resonance angiography has the advantage of a noninvasive method since it does not require ionizing radiation or an iodine contrast medium, and allows the evaluation of parenchymatous structures for additional diagnostic information.

Keywords: Angiography, Magnetic resonance imaging, Gadolinium

OBJECTIVE: To distinguish healthy from pathological tissues in pediatric patients with posterior cranial fossa tumors using calculated textural parameters from magnetic resonance images. MATERIALS AND METHODS: We evaluated 14 pediatric patients with posterior cranial fossa tumors using the software MaZda to define the texture parameters in selected regions of interest representing healthy and pathological tissues based on T2-weighted magnetic resonance images. RESULTS: There was a statistically significant difference between normal and tumoral tissues as well as between supposedly normal tissues adjacent and distant from the tumoral lesion. CONCLUSION: Magnetic resonance textural evaluation is an useful tool for determining differences among various tissues, including tissues that appear apparently normal on visual analysis.

Keywords: Magnetic resonance imaging, Textural evaluation, Posterior cranial fossa tumors, Pediatric patients, MaZda software

OBJECTIVE: To evaluate the qualitative (morphological) and quantitative characteristics of hepatic hemangiomas with magnetic resonance imaging. MATERIAL AND METHODS: Twenty-seven patients with 57 hemangiomas were prospectively studied with magnetic resonance imaging using a system operating at 1.5 T. T1- and T2-weighted spin-echo images were obtained, including heavily T2-weighted images with TE of 160 ms. The morphological characteristics of the hemangiomas were studied and the lesions were classified as typical or atypical. Quantitative parameters (T2 relaxation time, simplified T2 index and lesion/liver signal intensity ratio) were also calculated. The values obtained for typical and atypical hemangiomas were compared as well as for the hemangiomas measuring £ 2.0 cm and > 2.0 cm. RESULTS: 78.9% of hemangiomas showed typical morphological features. There was no difference between the quantitative values for typical and atypical hemangiomas. There was not significant difference in T2 relaxation times and values of simplified T2 index in hemangiomas measuring £ 2.0 cm and > 2.0 cm. Lesion/liver signal intensity ratios showed significant differences between the two groups. T2 relaxation times, the simplified T2 index and the lesion/liver signal intensity ratios correctly characterized 96.5%, 93%, and 89.5% of the hemangiomas, respectively. CONCLUSION: Quantitative analysis of hepatic hemangiomas is a simple technique that in conjunction with morphological evaluation provides a more reliable characterization of these tumors.

Keywords: Liver, Hemangioma, Magnetic resonance imaging

Magnetic resonance imaging is currently an important method for the assessment of the liver. As with helical computed tomography, the use of fast magnetic resonance imaging sequences to obtain data from the different phases of vascularization allows the detection and identification of tumors. However, some lesions may mimic true parenchymatous lesions which are interpretation pitfalls. These lesions are called pseudolesions and may occur due to perfusion defects, focal fatty infiltration, and spared areas of fatty liver or artifacts, among other causes. The recognition of these lesions is essential to avoid false-positive results. The aim of this study was to classify, illustrate, and briefly describe these pseudolesions, and to provide alternatives to differentiate pseudolesions from true parenchymatous lesions.

Keywords: Liver, Magnetic resonance imaging, Pitfalls

Thirty-three patients with chronic schizophrenia and 21 normal subjects were submitted to magnetic resonance imaging studies using a 1.5 T scanner. Axial and coronal T2-weighted images were obtained. The volumes of the brain, intracranial, supratentorial, infratentorial and the total, ventricular and subarachnoid cerebrospinal fluid volumes were measured using semi-automated morphometric methods. The volumes of the amygdala-hippocampus complex, parahippocampal gyrus cortex, putamen, globus pallidus, temporal lobe , gray and white matter of temporal lobe were also measured. These volumes were normalized using the intracranial volume as reference. The most relevant findings observed were reduced brain volume and increased total, ventricular and subarachnoid cerebrospinal fluid volumes in patients with schizophrenia when compared to the controls. Patients with schizophrenia had also smaller amygdala-hippocampus complexes, temporal lobes and temporal lobe white matter than the controls, as well as increased putamen volumes.

Keywords: Schizophrenia. Magnetic resonance imaging. Morphometry.

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.

OBJECTIVE: To assess the feasibility and reliability of apparent diffusion coefficient (ADC) measurements of normal adrenal glands. MATERIALS AND METHODS: This was a retrospective study involving 32 healthy subjects, divided into two groups: prepubertal (PreP, n = 12), aged from 2 months to 12.5 years (4 males; 8 females); and postpubertal (PostP, n = 20), aged from 11.9 to 61 years (5 males; 15 females). Diffusion-weighted magnetic resonance imaging (DW-MRI) sequences were acquired at a 1.5 T scanner using b values of 0, 20, 500, and 1000 s/mm². Two radiologists evaluated the images. ADC values were measured pixel-by-pixel on DW-MRI scans, and automatic co-registration with the ADC map was obtained. RESULTS: Mean ADC values for the right adrenal glands were 1.44 × 10^–3 mm²/s for the PreP group and 1.23 × 10^–3 mm²/s for the PostP group, whereas they were 1.58 × 10^–3 mm²/s and 1.32 × 10^–3 mm²/s, respectively, for the left glands. ADC values were higher in the PreP group than in the PostP group (p < 0.05). Agreement between readers was almost perfect (intraclass correlation coefficient, 0.84–0.94; p < 0.05). CONCLUSION: Our results demonstrate the feasibility and reliability of performing DW-MRI measurements of normal adrenal glands. They could also support the feasibility of ADC measurements of small structures.

Keywords: Adrenal glands; Diffusion magnetic resonance imaging; Magnetic resonance imaging.

OBJECTIVE: To determine whether preterm infants diagnosed with intracranial hemorrhage (by transfontanellar ultrasound) at birth have cerebral lesions that are detectable by magnetic resonance imaging (MRI) upon reaching school age. MATERIALS AND METHODS: MRI scans of the brain were obtained in 22 school-age children. Fifteen had presented intracranial hemorrhage at birth, and seven had not. We calculated the odds ratio (OR) for the occurrence of brain alterations detectable by MRI and the kappa index for discrepancies among the radiological reports. RESULTS: The children without previous intracranial hemorrhage presented normal MRI findings. Of the 15 children with previous intracranial hemorrhage, 6 (40%) presented brain alterations on MRI: isolated ventricular alteration (dilation and asymmetry), in 2 (13.3%); and ventricular asymmetry accompanied by parenchymal lesion, in 4 (26.7%). The nine remaining children with previous intracranial hemorrhage (60%) presented normal MRI findings. The children with previous intracranial hemorrhage were more likely to present ventricular alteration (OR = 7.8) and parenchymal lesions (OR = 5.4). CONCLUSION: Ventricular and parenchymal brain alterations detected by MRI suggest isolated morphologic alterations that do not result in neurological impairment detectable on physical examination in school-age children.

Keywords: Newborn; Premature; Intra]cranial hemorrhage; Magnetic resonance imaging; Child.

Diffusion-weighted imaging (DWI) is widely used in protocols for magnetic resonance imaging (MRI) of the female pelvis. It provides functional and structural information about biological tissues, without the use of ionizing radiation or intravenous administration of contrast medium. High signal intensity on DWI with simultaneous low signal intensity on apparent diffusion coefficient maps is usually associated with malignancy. However, that pattern can also be seen in many benign lesions, a fact that should be recognized by radiologists. Correlating DWI findings with those of conventional (T1- and T2-weighted) MRI sequences and those of contrastenhanced MRI sequences is mandatory in order to avoid potential pitfalls. The aim of this review article is the description of the most relevant physiological and benign pathological conditions of the female pelvis that can show restricted diffusion on DWI.

Keywords: Diffusion magnetic resonance imaging; Magnetic resonance imaging; Pelvis/diagnostic imaging.

Developments in magnetic resonance imaging have expanded its role in the assessment of the female pelvis, including the diagnosis of ovarian lesions. In this setting, diffusion-weighted imaging has proven its diagnostic value, which is particularly important in differentiating between benign and malignant ovarian tumors. In general, the latter show restricted diffusion, whereas the former do not. Exceptions include teratomas, endometriomas, hemorrhagic cysts, ovarian abscesses, ovarian infarction, and some benign stromal tumors. The aim of this review is to draw attention to benign ovarian lesions with restricted diffusion, with a special focus on diffusion-weighted imaging pearls and pitfalls.

Keywords: Diffusion magnetic resonance imaging; Magnetic resonance imaging; Pelvic neoplasms; Ovary.

The cranial nerves, which represent extensions of the functional structures of the brain, traverse the head and neck. They are connected to various cranial structures and are associated with several diseases. An in-depth understanding of their complex anatomy and normal imaging appearance allows the examiner to identify and characterize abnormalities with greater precision. One important tool for evaluating the cranial nerves is contrast-enhanced magnetic resonance imaging, especially that employing three-dimensional steady-state free precession sequences, which provide high soft-tissue and spatial resolution, despite the slenderness of the nerves. In most cases of cranial nerve abnormalities, the imaging findings are nonspecific. Therefore, to narrow the differential diagnosis, it is necessary to take a full patient history, perform a focused physical examination, and order laboratory tests. In this pictorial essay, we review, illustrate, and discuss, from a pathophysiological perspective, infectious, neoplastic, and demyelinating disorders, as well as other inflammatory disorders, affecting the cranial nerves, the aim being to provide a practical, tangible reference for radiologists to use in daily practice.

Keywords: Cranial nerves/physiopathology; Cranial nerve diseases/diagnostic imaging; Demyelinating diseases/diagnostic imaging; Magnetic resonance imaging/methods.