OBJECTIVE: To investigate and describe clinical, radiologic and pathologic findings of gastrointestinal stromal tumors. MATERIALS AND METHODS: In the period between December 2000 and March 2006, 16 patients were submitted to surgery for gastrointestinal stromal tumors in our institution. The following variables were taken into consideration: sex and age, signs and symptoms at presentation, tumor site and size, radiological and pathological features, and presence of metastasis. RESULTS: The study population was constituted by nine men and seven women. The primary tumor sites of origin were: stomach (n = 5), rectum (n = 4), small bowel (n = 3), mesentery (n = 3), and colon (n = 1). Mean primary tumor size was 9 cm. Computed tomography was the main radiological method utilized. Circumscribed, lobulated and heterogeneously contrast-enhanced mass was the main image finding. Metastasis was found in nine patients (56% of cases) at presentation or tumor recurrence was observed during the follow-up period (mean = 32 months). CONCLUSION: Gastrointestinal stromal tumor occurs in middle-age adults and the elderly, and must be taken into consideration as differential diagnosis for abdominal masses. Early diagnosis, adequate therapy, and rigorous follow-up are essential, considering the high probability of malignancy of these neoplasms as demonstrated by the present study.

Keywords: Gastrointestinal stromal tumor, Gastrointestinal neoplasms, Gastrointestinal diseases, Sarcoma

OBJECTIVE: The aim of the present study was to analyze splenic impedance indices - resistive index (RI) and pulsatility index (PI) - in patients with chronic liver disease. MATERIALS AND METHODS: Forty-two patients with hepatic cirrhosis and 21 patients with chronic hepatitis were prospectively evaluated. RESULTS: In patients with cirrhosis, both indices were higher (RI = 0.63 ± 0.08; PI = 1.02 ± 0.22) than those found in patients with chronic hepatitis (RI = 0.58 ± 0.06; PI = 0.89 ± 0.15) and in the control group individuals (RI = 0.57 ± 0.04; PI = 0.87 ± 0.11). However, cirrhotic patients with evidence of collateral circulation at ultrasound presented lower resistive indices (RI = 0.60 ± 0.08) compared with those without collateral circulation (RI = 0.65 ± 0.07), possibly due to the portosystemic shunt caused by collateral vessels. There was no significant difference of indices between patients with and without esophageal varices. CONCLUSION: The present study has demonstrated that splenic artery impedance indices may be useful in the evaluation of patients affected by chronic liver disease and portal hypertension, contributing with additional data at color Doppler ultrasound.

Keywords: Impedance indices, Splenic artery, Portal hypertension, Radiology

OBJECTIVE: The aim of this study is to describe the main radiological aspects of postoperative intestinal obstruction in patients submitted to Roux-en-Y gastric bypass by means of the Higa's technique. MATERIALS AND METHODS: A total of 10 patients presenting with postoperative intestinal obstruction following a gastric reduction procedure were evaluated in the period between November 2001 and April 2006, in seven different medical centers. RESULTS: In the ten patients, the obstruction occurred in the small bowel, five of them because of internal hernias, three because of adhesions, one because of an umbilical hernia and one because of intussusception. Four patients presented obstruction early in the postoperative period (by the seventh post-op day), and six, late in the postoperative period (between the third month and the fifth year). CONCLUSION: All of the cases of intestinal obstruction were found in the small bowel. Internal hernia was the most frequent cause, followed by adhesion. Other causes included umbilical hernia and intussusception.

Keywords: Morbid obesity, Bariatric surgery, Intestinal obstruction, Complication, Radiology, Computed tomography

OBJECTIVE: The present study was aimed at evaluating main radiological and epidemiological aspects of giant cell lesions (central giant cell granuloma and brown tumors of hyperparathyroidism). MATERIALS AND METHODS: The sample consisted of 26 giant cell lesions diagnosed in 22 patients divided into two groups, one of them including 17 patients who were not affected by hyperparathyroidism (group A) and another including five patients with such a disorder (group B). RESULTS: Prevalence was higher in female patients (72.7%). Most frequently, lesions occurred more in the second decade of life (mean age, 27 years). The mandible arc was most frequently involved (61.5%). Radiographically, 57.7% of lesions were multilocular and 42.3% were unilocular with defined limits. All of the 26 lesions caused expansion of bone, 15.4% radicular resorption, 50% dental displacement, and 11.5% produced pain. In the mandible 18.7% of the lesions crossed the midline. Group A showed 66.7% of lesions in the mandible and group B showed an even distribution of lesions between arches. In group A 66.7% of lesions were multilocular, and 33.3% unilocular; in group B 62.5% were unilocular, and 37.5% multilocular. CONCLUSION: Giant cells lesions may present themselves with a wide spectrum, from small, slow-growing unilocular lesions to extensive multilocular lesions. They present features of benignity, though some lesions may demonstrate a locally aggressive behavior.

Keywords: Central giant cell granuloma, Radiological aspects, Brown tumor, Hyperparathyroidism

OBJECTIVE: To review the literature about the positive predictive value of Breast Imaging Reporting and Data System (BI-RADS®) categories 3, 4 and 5. MATERIALS AND METHODS: A research was performed in the online Medline database, entering the terms "predictive value" and "BI-RADS". Eleven studies were included in this review. RESULTS: The positive predictive values ranged respectively between 0% and 8%, 4% and 62%, and 54% and 100% for BI-RADS® categories 3, 4 and 5. Three studies have also evaluated morphological criteria with higher positive predictive value in mammography, mass with spiculated margins being the finding with highest positive predictive value for malignancy. CONCLUSION: A high variability was found in the reviewed literature among positive predictive values of BI-RADS® categories 3, 4 and 5, although methodological differences have been identified, limiting the comparative analysis.

Keywords: Mammography, BI-RADS®, Breast cancer

OBJECTIVE: To evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) of the knee. MATERIALS AND METHODS: Seventy-two patients have been submitted to MRI previously to arthroscopy of the knee performed by a single surgeon and utilized as a comparative standard method. Sensitivity, specificity, values of likelihood and rate of interobserver agreement have been evaluated. RESULTS: The kappa agreement coefficient between MRI and arthroscopy was very good for lesions in the anterior cruciate ligament (0.84), good for lateral meniscus (0.75), reasonable for medial meniscus (0.50) and poor for chondral lesions (< 0.50). MRI has demonstrated high sensitivity for tears in the anterior cruciate ligament (94%) and in the medial meniscus (92%), good sensitivity for lesions in the lateral meniscus (80%), and low sensitivity for lesions in all of the chondral zones (< 50%), while the specificity has been excellent for all the chondral, and ligamentous structures, besides the lateral menisci analyzed (more than 97%), and reasonable (65%) for the medial meniscus. CONCLUSION: MRI is a useful tool in the clinical diagnosis of intra-articular knee lesions, as already demonstrated by similar results reported both in the Brazilian and international literature.

Keywords: Arthroscopy, Magnetic resonance imaging, Knee, Lesions, Sensitivity, Specificity

OBJECTIVE: To study the interchangeability of the bone mineral density results between Hologic® dual energy x-ray absorptiometry (DEXA) and Cromox® computed dual energy conventional x-ray absorptiometry (CDEXA) equipments. MATERIALS AND METHODS: Thirty-eight femoral necks and 31 lumbar spines of 43 patients underwent bone mineral density measured by both equipments in a diagnostic imaging center. The Cromox® equipment was calibrated with a reference Cromox® phantom for bone absorptiometry. RESULTS: A strong correlation between results obtained from the two devices was found for each skeletal site. The linear correlation coefficient measured for the right femoral neck was r = 0.920, p < 0.0001, and r = 0.923, p < 0.0001 for the lumbar spine L2-L4 vertebrae. Considering the relevance of the Tscore result in the clinical practice for bone densitometry, the mean difference of the Tscore between devices was calculated, resulting in an arithmetic mean DTscore = 0.191 for hips and an arithmetic mean DTscore = 0.228 for the lumbar spines. The skeletal status is established according to the World Health Organization definition as normal, osteopenia or osteoporosis. The skeletal status concordance between devices was higher than 76% for hips and higher than 77% for spines; and higher than 96% when considering concordance in at least one of the two sites. CONCLUSION: The linear correlation coefficients obtained are very close to the international references among gold standard devices, reported as r > 0.95. For both sites, the arithmetic mean difference in Tscore between devices is low - least than the lowest significant variance.

Keywords: Dual energy x-ray absorptiometry, Dual energy radiographic absorptiometry, Computed x-ray densitometry, Correlation, Interchangeability

OBJECTIVE: To investigate the effects of radiotherapy on bone tissues and the accuracy of gray level measurements on radiographic images. MATERIALS AND METHODS: Four Wistar rats were submitted to external radiotherapy (single 3000 cGy dose) on an area of 2 cm × 2 cm of their right legs. The animals were sacrificed six weeks after radiotherapy, and both irradiated and contralateral (non-irradiated) legs were removed, dissected, evaluated for thickness, x-rayed in a standardized form and histologically processed (stained with hematoxylin-eosin and picrosirius red). The radiographs were digitalized and the gray level average was measured with the ImageTool® software. RESULTS: The femur thickness of non-irradiated legs was greater than that of the irradiated legs (p < 0.05). Radiographically, the findings indicated a higher bone density in the non-irradiated legs, although with no statistically significant difference (p > 0.05). Histological analysis of the irradiated legs demonstrated a decrease in the number of osteocytes and Haversian canals, although with no statistically significance (p > 0.05). On the other hand, a significant increase in adipocytes was observed, resulting in a reduction of medullary tissue in the irradiated legs (p < 0.05), besides a higher osteoblastic activity in the non-irradiated legs (p < 0.05). CONCLUSION: Radiotherapy within the above mentioned parameters determined a decrease in activity of bone remodeling, which could be radiographically detected in the majority of the evaluated specimens.

Keywords: Radiotherapy, Ionizing radiation, Bone tissue

Acute appendicitis is the most important cause of abdominal pain requiring surgical intervention in the Western world. The early diagnosis of this disease is of paramount relevance for minimizing its morbidity. Imaging methods have represented a huge progress in the diagnosis of this entity, which used to be based essentially on clinical history, physical examination and laboratory tests results, considering that 20% to 33% of patients present with atypical symptoms. Diagnostic difficulty is higher in children, the elderly, and women in childbearing age. The main imaging methods for evaluation of acute appendicitis are ultrasound and computed tomography. The present study is aimed at describing the disease physiopathology, commenting main computed tomography technical aspects, demonstrating and illustrating tomographic findings, and describing main differential diagnoses.

Keywords: Acute appendicitis, Vermiform appendix, Computed tomography

For the last years three-dimensional ultrasonography has become an imaging diagnosis method of great importance in obstetrics. One of its advantages would be the higher sensitivity compared with two-dimensional ultrasound in the diagnosis of some fetal malformations. The potential applications of this new method would be an improved accuracy in the measurement of fetal organs, the possibility of reviewing volumes in the absence of the patient, and using different planes to assess specific anatomical structures, as well as the capacity to transfer data files to remote reference centers. Ultrasonographic evaluation of fetal cerebellum is particularly important, since developmental alterations are correlated with the fetal growth alterations and congenital anomalies. The objective of this updating is to demonstrate the VOCAL™ and 3D XI™ methods in the evaluation of the fetal cerebellum, their potential benefits, and the latest information in the literature about this subject.

Keywords: Fetus, Cerebellum, Volume of organs, Prenatal diagnosis, Three-dimensional ultrasound

Cervical cancer is the worldwide leading cause of cancer-related death of women, especially in developing countries. The International Federation of Gynecology and Obstetrics recommends staging during surgery, however, surgical-pathologic staging would not be feasible in cases of more advanced cancers. Generally, in these cases, the staging is performed by means of clinical and gynecological examination and basic imaging studies. However, such an approach fails to demonstrate the actual extent of the disease, and does not include significant prognostic factors such as tumor volume, stromal invasion and lymph node involvement. Magnetic resonance imaging has increasingly been utilized in cervical cancer staging, since at early stages of the disease its performance may be compared to intraoperative findings and, at advanced stages, it shows to be superior to the clinical evaluation. Additionally, magnetic resonance imaging presents an excellent imaging resolution for the different densities of pelvic structures, does not require ionizing radiation, is comfortable for the patient, improves de staging, allowing the early detection of recurrence and the identification of reliable prognostic factors which contribute to the therapeutic decision making process and results prediction with an excellent cost-effectiveness. The present article is aimed at reviewing the most significant aspects of magnetic resonance imaging in the cervical cancer staging.

Keywords: Cervical cancer, Staging, Magnetic resonance imaging

A case of a male, 29-year-old patient who, in a suicide attempt, has self-administered a 2 ml injection of metallic mercury into his left arm is reported. Radiological studies have shown the presence of several metallic spheres in the subcutaneous tissue of the olecranal fossa and along the veins of the left arm, with dissemination to lungs, heart, liver, spleen and brain.

Keywords: Embolism, Mercury, Radiology, Computed tomography