Posterior migration of lumbar disc herniation - imaging dilemma due to contrast contraindication: a case report

Disc herniation with posterior epidural migration is a rare and often symptomatic entity. Multiple are the natural barriers that prevent this pattern of migration. Enhanced magnetic resonance imaging is the diagnostic modality of choice in these cases. The diagnostic dilemma in this case was the contraindication to the use of contrast since the patient was known to have chronic renal failure.

Aesthetic breast augmentation with hyaluronic acid: imaging findings and implications for radiological assessment

New injectable fillers such as hyaluronic acid have recently been employed as a non-surgical alternative to implants such as silicone for aesthetic breast enhancement. Although their utilization is not yet widespread in Brazil, radiologists should be aware of the imaging findings in this context and of the implications of the presence of this filler for the radiological evaluation in the screening for breast cancer.

Trapped periosteum in a distal femoral physeal injury: magnetic resonance imaging evaluation

Epiphyseal fractures are frequently associated with knee trauma during sports in children and adolescents. Usually, Salter-Harris types I and II fractures are conservatively treated. However, failed closed reduction of displaced fractures suggest the presence of trapped periosteum, with indication for surgery. The present report describes a case of Salter-Harris type I fracture of the distal femur in a child, complicated with trapped periosteum detected at magnetic resonance imaging.

Magnetic resonance imaging findings of disc-related epidural cysts in nonsurgical and postoperative microdiscectomy patients

OBJECTIVE: To demonstrate five discal cysts with detailed magnetic resonance imaging findings in nonsurgical and following postoperative microdiscectomy. MATERIALS AND METHODS: Five discal cysts in four patients who underwent magnetic resonance imaging were found through a search in our database and referral from a single orthopedic spine surgeon. Computed tomography in two cases and computed tomography discography in one case were also performed. RESULTS: Five discal cysts were present in four patients. Three patients had no history of previous lumbar surgery and the other patient presented with two discal cysts and recurrent symptoms after partial laminectomy and microdiscectomy. All were oval shaped and seated in the anterior epidural space. Four were ventrolateral, and the other one was centrally positioned in the anterior spinal canal. One showed continuity with the central disc following discography. Three were surgically removed. CONCLUSION: Magnetic resonance imaging can easily depict an epidural cyst and the diagnosis of a discal cyst should be raised when an homogeneous ventrolateral epidural cyst contiguous to a mild degenerated disc is identified.

Connectivity and tissue microstructural alterations in right and left temporal lobe epilepsy revealed by diffusion spectrum imaging.

Focal epilepsy is increasingly recognized as the result of an altered brain network, both on the structural and functional levels and the characterization of these widespread brain alterations is crucial for our understanding of the clinical manifestation of seizure and cognitive deficits as well as for the management of candidates to epilepsy surgery. Tractography based on Diffusion Tensor Imaging allows non-invasive mapping of white matter tracts in vivo. Recently, diffusion spectrum imaging (DSI), based on an increased number of diffusion directions and intensities, has improved the sensitivity of tractography, notably with respect to the problem of fiber crossing and recent developments allow acquisition times compatible with clinical application. We used DSI and parcellation of the gray matter in regions of interest to build whole-brain connectivity matrices describing the mutual connections between cortical and subcortical regions in patients with focal epilepsy and healthy controls. In addition, the high angular and radial resolution of DSI allowed us to evaluate also some of the biophysical compartment models, to better understand the cause of the changes in diffusion anisotropy. Global connectivity, hub architecture and regional connectivity patterns were altered in TLE patients and showed different characteristics in RTLE vs LTLE with stronger abnormalities in RTLE. The microstructural analysis suggested that disturbed axonal density contributed more than fiber orientation to the connectivity changes affecting the temporal lobes whereas fiber orientation changes were more involved in extratemporal lobe changes. Our study provides further structural evidence that RTLE and LTLE are not symmetrical entities and DSI-based imaging could help investigate the microstructural correlate of these imaging abnormalities.

Characterisation of anatomical properties of the human basal ganglia using magnetic resonance imaging

The detailed in-vivo characterization of subcortical brain structures is essential not only to understand the basic organizational principles of the healthy brain but also for the study of the involvement of the basal ganglia in brain disorders. The particular tissue properties of basal ganglia - most importantly their high iron content, strongly affect the contrast of magnetic resonance imaging (MRI) images, hampering the accurate automated assessment of these regions. This technical challenge explains the substantial controversy in the literature about the magnitude, directionality and neurobiological interpretation of basal ganglia structural changes estimated from MRI and computational anatomy techniques. My scientific project addresses the pertinent need for accurate automated delineation of basal ganglia using two complementary strategies: ? Empirical testing of the utility of novel imaging protocols to provide superior contrast in the basal ganglia and to quantify brain tissue properties; ? Improvement of the algorithms for the reliable automated detection of basal ganglia and thalamus Previous research demonstrated that MRI protocols based on magnetization transfer (MT) saturation maps provide optimal grey-white matter contrast in subcortical structures compared with the widely used Tl-weighted (Tlw) images (Helms et al., 2009). Under the assumption of a direct impact of brain tissue properties on MR contrast my first study addressed the question of the mechanisms underlying the regional specificities effect of the basal ganglia. I used established whole-brain voxel-based methods to test for grey matter volume differences between MT and Tlw imaging protocols with an emphasis on subcortical structures. I applied a regression model to explain the observed grey matter differences from the regionally specific impact of brain tissue properties on the MR contrast. The results of my first project prompted further methodological developments to create adequate priors for the basal ganglia and thalamus allowing optimal automated delineation of these structures in a probabilistic tissue classification framework. I established a standardized workflow for manual labelling of the basal ganglia, thalamus and cerebellar dentate to create new tissue probability maps from quantitative MR maps featuring optimal grey-white matter contrast in subcortical areas. The validation step of the new tissue priors included a comparison of the classification performance with the existing probability maps. In my third project I continued investigating the factors impacting automated brain tissue classification that result in interpretational shortcomings when using Tlw MRI data in the framework of computational anatomy. While the intensity in Tlw images is predominantly

Incidental enchondromas at knee magnetic resonance imaging: intraobserver and interobserver agreement and prevalence of imaging findings

Objective To evaluate intra- and interobserver agreement in the identification of incidental enchondromas at knee magnetic resonance imaging, and to assess the prevalence of imaging findings. Materials and Methods Retrospective study reviewing 326 knee magnetic resonance images acquired in the period between November 2009 and September 2010. The images were independently and blindly analyzed by two specialists in musculoskeletal radiology, with the objective of identifying incidental enchondromas, presence of foci with signal similar to bone marrow and foci of signal absence suggestive of calcifications within the enchondromas. Inter- and intraobserver agreements were analyzed. Results Eleven lesions compatible with enchondromas (3.3%) were identified. The interobserver agreement for the presence of enchondroma was high. Prevalence of foci of bone marrow signal inside the enchondromas was of 54.55%, and foci suggestive of calcification corresponded to 36.36%. The intraobserver agreement for foci of bone marrow signal in enchondromas was perfect, and interobserver agreement was high. Conclusion The prevalence of incidental enchondromas in the current study was compatible with data in the literature. Excellent agreement was observed in the identification of enchondromas and in the assessment of imaging findings. A higher prevalence of fat signal foci was observed as compared with signal absence suggestive of calcifications.

Pyogenic and tuberculous discitis: magnetic resonance imaging findings for differential diagnosis

Spondylodiscitis represents 2%–4% of all bone infections cases. The correct diagnosis and appropriate treatment can prevent complications such as vertebral collapse and spinal cord compression, avoiding surgical procedures. The diagnosis is based on characteristic clinical and radiographic findings and confirmed by blood culture and biopsy of the disc or the vertebra. The present study was developed with Clementino Fraga Filho University Hospital patients with histopathologically and microbiologically confirmed diagnosis of spondylodiscitis, submitted to magnetic resonance imaging of the affected regions. In most cases, pyogenic spondylodiscitis affects the lumbar spine. The following findings are suggestive of the diagnosis: segmental involvement; ill-defined abscesses; early intervertebral disc involvement; homogeneous vertebral bodies and intervertebral discs involvement. Tuberculous spondylodiscitis affects preferentially the thoracic spine. Most suggestive signs include: presence of well-defined and thin-walled abscess; multisegmental, subligamentous involvement; heterogeneous involvement of vertebral bodies; and relative sparing of intervertebral discs. The present pictorial essay is aimed at showing the main magnetic resonance imaging findings of pyogenic and tuberculous discitis.

Diffusion-weighted magnetic resonance imaging: biomarker for treatment response in oncology

The authors report a case where a quantitative assessment of the apparent diffusion coefficient (ADC) of liver metastasis in a patient undergoing chemotherapy has shown to be an effective early marker for predicting therapeutic response, anticipating changes in tumor size. A lesion with lower initial ADC value and early increase in such value in the course of the treatment tends to present a better therapeutic response.

Prevalence of simple liver cysts and hemangiomas in cirrhotic and non-cirrhotic patients submitted to magnetic resonance imaging

Objective To determine the prevalence of liver cysts and hemangiomas in the general population and in cirrhotic patients. Materials and Methods Retrospective, observational, and cross-sectional study selecting consecutive magnetic resonance imaging studies performed in the period from February to July 2011. A total of 303 patients (187 women and 116 men) with mean age of 53.3 years were included in the present study. Patients with previously known liver lesions were excluded. The images were consensually analyzed by two observers in the search for simple liver cysts and typical liver hemangiomas, according to universally accepted imaging criteria. Lesions prevalence, diameters and location were determined in both cirrhotic and non-cirrhotic individuals. Results The authors observed prevalence of 8.6% for hemangiomas and 14.5% for simple cysts. No statistically significant difference was observed in relation to prevalence of hemangiomas and cysts among cirrhotic and non-cirrhotic patients (p = 0.954; p = 0.472). Conclusion In the present study, the prevalence of cysts and hemangiomas was higher than the prevalence reported by autopsy series. No influence of cirrhosis was observed on the prevalence and appearance of such incidental lesions.

Positive predictive values of Breast Imaging Reporting and Data System (BI-RADS®) categories 3, 4 and 5 in breast lesions submitted to percutaneous biopsy

Objective To evaluate the BI-RADS as a predictive factor of suspicion for malignancy in breast lesions by correlating radiological with histological results and calculating the positive predictive value for categories 3, 4 and 5 in a breast cancer reference center in the city of São Paulo. Materials and Methods Retrospective, analytical and cross-sectional study including 725 patients with mammographic and/or sonographic findings classified as BI-RADS categories 3, 4 and 5 who were referred to the authors' institution to undergo percutaneous biopsy. The tests results were reviewed and the positive predictive value was calculated by means of a specific mathematical equation. Results Positive predictive values found for categories 3, 4 and 5 were respectively the following: 0.74%, 33.08% and 92.95%, for cases submitted to ultrasound-guided biopsy, and 0.00%, 14.90% and 100% for cases submitted to stereotactic biopsy. Conclusion The present study demonstrated high suspicion for malignancy in lesions classified as category 5 and low risk for category 3. As regards category 4, the need for systematic biopsies was observed.

Congenital inferior vena cava anomalies: a review of findings at multidetector computed tomography and magnetic resonance imaging

Inferior vena cava anomalies are rare, occurring in up to 8.7% of the population, as left renal vein anomalies are considered. The inferior vena cava develops from the sixth to the eighth gestational weeks, originating from three paired embryonic veins, namely the subcardinal, supracardinal and postcardinal veins. This complex ontogenesis of the inferior vena cava, with multiple anastomoses between the pairs of embryonic veins, leads to a number of anatomic variations in the venous return from the abdomen and lower limbs. Some of such variations have significant clinical and surgical implications related to other cardiovascular anomalies and in some cases associated with venous thrombosis of lower limbs, particularly in young adults. The authors reviewed images of ten patients with inferior vena cava anomalies, three of them with deep venous thrombosis. The authors highlight the major findings of inferior vena cava anomalies at multidetector computed tomography and magnetic resonance imaging, correlating them the embryonic development and demonstrating the main alternative pathways for venous drainage. The knowledge on the inferior vena cava anomalies is critical in the assessment of abdominal images to avoid misdiagnosis and to indicate the possibility of associated anomalies, besides clinical and surgical implications.

Imaging evaluation of middle ear cholesteatoma: iconographic essay

Middle ear cholesteatoma is a relevant and relatively common disease that may have severe consequences. In the present pictorial essay, the authors have selected illustrative examples of multislice computed tomography and magnetic resonance imaging depicting the main presentations of cholesteatomas, and describing their characteristics, locations, and major complications.

Construction of an index of information from clinical practice in Radiology and Imaging Diagnosis based on text mining and thesaurus

Objective To construct a Portuguese language index of information on the practice of diagnostic radiology in order to improve the standardization of the medical language and terminology. Materials and Methods A total of 61,461 definitive reports were collected from the database of the Radiology Information System at Hospital das Clínicas – Faculdade de Medicina de Ribeirão Preto (RIS/HCFMRP) as follows: 30,000 chest x-ray reports; 27,000 mammography reports; and 4,461 thyroid ultrasonography reports. The text mining technique was applied for the selection of terms, and the ANSI/NISO Z39.19-2005 standard was utilized to construct the index based on a thesaurus structure. The system was created in *html. Results The text mining resulted in a set of 358,236 (n = 100%) words. Out of this total, 76,347 (n = 21%) terms were selected to form the index. Such terms refer to anatomical pathology description, imaging techniques, equipment, type of study and some other composite terms. The index system was developed with 78,538 *html web pages. Conclusion The utilization of text mining on a radiological reports database has allowed the construction of a lexical system in Portuguese language consistent with the clinical practice in Radiology.

The knowledge about diagnostic imaging methods among primary care and medical emergency physicians

Objective To evaluate the knowledge about diagnostic imaging methods among primary care and medical emergency physicians. Materials and Methods Study developed with 119 primary care and medical emergency physicians in Montes Claros, MG, Brazil, by means of a structured questionnaire about general knowledge and indications of imaging methods in common clinical settings. A rate of correct responses corresponding to ≥ 80% was considered as satisfactory. The Poisson regression (PR) model was utilized in the data analysis. Results Among the 81 individuals who responded the questionnaire, 65% (n = 53) demonstrated to have satisfactory general knowledge and 44% (n = 36) gave correct responses regarding indications of imaging methods. Respectively, 65% (n = 53) and 51% (n = 41) of the respondents consider that radiography and computed tomography do not use ionizing radiation. The prevalence of a satisfactory general knowledge about imaging methods was associated with medical residency in the respondents' work field (PR = 4.55; IC 95%: 1.18-16.67; p-value: 0.03), while the prevalence of correct responses regarding indication of imaging methods was associated with the professional practice in primary health care (PR = 1.79; IC 95%: 1.16-2.70; p-value: 0.01). Conclusion Major deficiencies were observed as regards the knowledge about imaging methods among physicians, with better results obtained by those involved in primary health care and by residents.