OBJECTIVE: The present study was aimed at evaluating by means of magnetic resonance imaging a series of fetuses with sonographic diagnosis of malformation, establishing the diagnostic benefits and limitations of fetal magnetic resonance imaging as compared with ultrasonography. MATERIALS AND METHODS: Forty women between 15-35 gestational weeks and previously diagnosed with fetal abnormality by ultrasonography were referred to undergo complementary fetal magnetic resonance imaging, particularly for evaluating abnormalities in the fetal central nervous system, thorax, abdomen, renal system, skeletal system, and tumors. The whole evaluation process included a review of the fetal ultrasonography and magnetic resonance images, postnatal follow-up, laboratory tests, imaging studies and necropsy. RESULTS: The present study has demonstrated that complementary magnetic resonance imaging did provide further information in 60% of cases, with the following benefits: improved information on the fetus as a whole, with a large field of view, higher anatomic resolution provided by fast sequences, superior soft tissue contrast resolution, besides the fact that the visualization of the fetus is not significantly affected by maternal obesity or oligohydramnios. Limitations of the method include contraindication in the first gestational trimester and in cases of maternal claustrophobia, sensitivity to fetal motion, low sensitivity for detecting cardiovascular and skeletal malformations. CONCLUSION: Fetal magnetic resonance imaging plays a significant role as a complementary method for the diagnosis of fetal anomalies.

Keywords: Fetal magnetic resonance imaging, Ultrasonography, Malformations, Single-shot, HASTE, Prenatal diagnosis

Pathological processes of the testis are very frequently found, and include non-tumoral and tumoral lesions. Ultra-sonography performed with a high-frequency transducer has become the imaging modality of choice for examination of these organs. This method is of help to improve intratesticular lesions characterization, and in many instances the findings suggest a more specific diagnosis, especially in the presence of similar clinical manifestations such as pain, swelling and local increase in volume. Color Doppler is an invaluable tool for demonstrating anomalous patterns of testicular perfusion and aids in the diagnosis of acute clinical conditions. In the present iconographic essay, the authors summarize the most frequent clinical, pathological findings as well as the main diagnostic features of benign intratesticular lesions such as microlithiasis, simple cysts, spermatocele, varicocele, tubular ectasia of the rete testis, orchitis, hematomas and more rare conditions. Familiarity with clinical and sonographic features is essential for the correct diagnosis and starting of the most effective therapy, as necessary.

Keywords: Testis, Benign testicular lesions, Ultrasonography, Color Doppler

The use of unenhanced computed tomography has been frequently recommended for the initial assessment of patients with clinical suspicion of acute abdomen instead of other diagnostic methods. The authors present a review of the literature on the main aspects, advantages, limitations and efficacy of unenhanced computed tomography for the diagnosis of acute appendicitis, renal colic, diverticulitis, acute pancreatitis, primary epiploic appendicitis, pneumoperitoneum and small bowel obstruction. The advantages and limitations of this technique are also discussed.

Keywords: Appendicitis, Diverticulitis, Acute abdomen, Computed tomography, Contrast media

Breast reconstruction using myocutaneous flaps has been widely used in patients undergoing modified radical mastectomy for the treatment of breast cancer with significant improvement in esthetical results, which also helps to improve self-esteem of the patients as it minimizes the feeling of mutilation, without changing disease prognosis. Previously, it was believed that there was no risk of recurrence in the reconstructed breast due to the complete removal of breast tissue. However, histological studies have shown that a small amount of glandular tissue may remain after mastectomy, with a high potential for malignancy. Clinical follow-up of mastectomy patients is recommended as most recurring lesions occur at the flap margins and can be detected by palpation. In addition, the inclusion of mammographic and ultrasound monitoring has been proposed for the follow-up of patients as these methods may contribute to the diagnosis of recurrent lesions before they become palpable.

Keywords: Breast cancer, Mastectomy, Mammography, Ultrasound

OBJECTIVE: To evaluate the visibility of hepatomesenteric vascular segments by 3D gadolinium-enhanced magnetic resonance (MR) angiography and to compare the method effectiveness between two different gadolinium doses (single and double doses). MATERIALS AND METHODS: A prospective study was performed with 36 schistosomiasis patients who were submitted to 3D contrast-enhanced MR angiography. Scans were performed in a high-field equipment (1.5 T), with body coil and power injector for intravenous contrast administration. Contrast double doses (Gd-DTPA 0.2 mmol/kg) and single doses (0.1 mmol/kg) were randomly used respectively in 21 and 15 patients. Studies were interpreted by consensus between two observers who have rated the visualization degree of 25 proximal vascular segments without knowing the dose used. RESULTS: Proximal and calibrous vascular segments have presented higher visualization degree in the greatest part of the sample studied. The celiac trunk, common hepatic artery, splenic artery, proximal and medium third of superior mesenteric artery, portal vein, splenic vein and superior mesenteric vein have presented grade 2 visualization in more than 70% of the sample studied. As regards comparison between different doses, there was no significant difference (p < 0.05) in the visualization degree of several structures evaluated, between double dose and single dose groups, except for an isolate case of evaluation of right hepatic artery (p = 0.008) in which the single dose group has presented a higher frequency of grade 2 visualization with statistical significance. CONCLUSION: The visualization degree of hepatomesenteric vascular segments by 3D gadolinium-enhanced MR angiography is high, especially in the proximal and calibrous segments. The comparison between groups using single and double contrast doses has demonstrated similar results.

Keywords: Magnetic resonance angiography, Schistosomiasis, Gadolinium

OBJECTIVE: To evaluate the interobserver agreement on non-contrast computed tomography interpretation by a group of experienced abdominal radiologists, for the study of urolithiasis in patients presenting acute flank pain. MATERIALS AND METHODS: Prospective study of 52 patients submitted to non-contrast enhanced helical computed tomography. The images were subsequently analyzed by three independent observers, with the interobserver agreement assessed by means of the kappa (kappa) statistical method. The following parameters were analyzed: a) presence, localization and measurement of ureteral calculi; b) intrarenal calyceal system dilatation; c) perirenal fat heterogeneity; d) ureteral dilatation; e) ureteral wall edema (halo sign). RESULTS: Ureteral calculi were found in 40 of 52 patients (77%). The interobserver agreement was almost perfect as regards identification of ureteral calculi (kappa = 0.89) and ureteral dilatation (kappa = 0.87), substantial for calyceal system dilatation (kappa = 0.77), and moderate for perirenal fat heterogeneity (kappa = 0.55) and ureteral wall edema (kappa = 0.56). CONCLUSION: Non-contrast-enhanced abdominal computed tomography presents high reproducibility in the evaluation of urolithiasis and secondary signs of the calyceal system obstruction.

Keywords: Lithiasis, Ureteral calculi, Flank pain, Computed tomography

OBJECTIVE: To define, by means of computed tomography, the level of ureteral implantation into de bladder. MATERIALS AND METHODS: We have measured the distances from the ureteral meatus to the acetabulum, and to the superior margin of the pubic symphysis, as well as the bladder volume, using contrast enhanced computed tomography of the pelvis in 46 patients (31 male and 15 female) in the age range between 18 and 45 years, with at least one of the ureteres filled with excreted contrast material. The Student t test has been applied to determine eventual statistically significant differences between groups. RESULTS: The level of ureteral implantation into the bladder was, on average, 10.6 ± 8.1 mm below the acetabular roof, and 29.7 ± 9.5 mm above the superior margin of the pubic symphysis. In patients with bladder repletion volume of < 200 ml and > 200 ml, the level of ureteral implantation into the bladder was, respectively, on average, 11.6 ± 7.3 mm and 10.2 ± 8.4 mm below the acetabular roof (p = 0.61), and 28.3 ± 7.3 mm and 30.3 ± 10.2 mm above the superior margin of the pubic symphysis (p = 0.52), and in male and female men patients, respectively, on average, 11.8 ± 8.0 mm and 8.3 ± 8.0 mm below the acetabular roof (p = 0.17), and 27.7 ± 9.2 mm and 33.9 ± 8.8 mm above the superior margin of the pubic symphysis (p = 0.34). CONCLUSION: Calcifications located < 3 cm below the acetabular roof and < 1.5 cm above the superior margin of the pubic symphysis probably do not represent ureteral calculi. Vesical repletion or sex have no significant influence on the ureteral meatus position.

Keywords: Calculus, Ureter, Ureteral obstruction, Lithiasis, X-ray computed tomography

We present a case of a 27-year-old male patient submitted to computed tomography and magnetic resonance imaging for the evaluation of a renal tumor. The radiological features of the mass suggested the diagnosis of a malignant renal tumor of parenchymatous origin. However, the histological findings proved to be a benign solitary fibrous tumor within the pelvis and caliceal portion of the right kidney.

Keywords: Neoplasia, Fibrous tumor, Kidney, Mesothelioma, Computed tomography, Magnetic resonance imaging

OBJECTIVE: To determine the overall frequency of artifacts per type and grade using the GRASE sequence in abdominal magnetic resonance; to compare GRASE sequences with two previously selected TSE sequences as well as sequences with best signal-noise ratio and lower incidence of artifacts. MATERIALS AND METHODS: A prospective self-paired study was carried out in 86 patients submitted to upper abdominal magnetic resonance using a GRASE sequence obtained upon respiratory triggered and fat suppression and six TSE T2-weighted sequences. Among the six TSE sequences, those bearing the best signal-noise ratio and lower number of artifacts were previously selected, which consisted of those performed with fat suppression and respiratory triggering: one using a conventional body coil (sequence 1) and a second sequence using a synergy coil (sequence 2). Image analysis was carried out by two observers upon consensus regarding the presence, grade and type of artifact thereon. Subsequently, data were statistically analyzed using the Friedman test and chi-square. RESULTS: The absolute frequency of artifacts in all sequences was 65.02%. Most common artifacts in the three sequences analyzed were breathing (30%) and pulsation (33%) artifacts. Only in 3% of the cases artifacts interfered with the analysis of the images. The frequency of artifacts in the different sequences was: GRASE, 67.2%; TSE sequence 1, 62.2%; TSE sequence 2, 65.5%. There was no significant statistical difference between artifact frequency seen with GRASE and TSE sequences (p = 0.845; NS). CONCLUSION: GRASE and TSE T2-weighted, respiratory triggered, fat suppressed sequences often produce artifacts, notwithstanding the coil, although, with similar frequency and generally without interfering with the evaluation of the images.

Keywords: Artifact, Magnetic resonance, Abdomen

The distribution of fibroglandular tissue in the breast is often symmetrical. Changes in that symmetry may indicate a hidden lesion in the parenchyma. The evaluation of asymmetric densities in the breast is one of the main day-to-day challenges for radiologists, i.e., differentiating normal superimposed structures from true parenchymal lesions. The knowledge of different techniques and resources used to investigate asymmetric densities as well as evaluation protocols are essential to establish the nature of the lesions. Asymmetric densities may be the only sign of breast cancer otherwise clinically and radiologically concealed.

Keywords: Asymmetric density, Mammography, Invasive lobular carcinoma

OBJECTIVE: To qualitatively and quantitatively evaluate the morphological changes of the liver and spleen using magnetic resonance imaging (MRI) in patients with chronic infection by Schistosoma mansoni and the reproducibility of MRI findings in the hepatosplenic evaluation of these patients. MATERIALS AND METHODS: We prospectively studied 28 schistosomotic patients submitted to MRI of the upper abdomen. The scans were performed using a high field equipment (1.5 T), a body coil and a power injector for administration of intravenous contrast. The scans were interpreted by two independent examiners who evaluated the presence of morphological changes in the liver and spleen. Interobserver and intraobserver agreement were measured using the kappa and intraclass correlation tests. RESULTS: Qualitative variables presented good interobserver and intraobserver agreement (kappa > 0.65 and r > 0.66, respectively). The best interobserver agreement was for the anteroposterior diameter of the spleen (r = 0.98). The observers identified reduction of the right hepatic lobe, enlargement of the left hepatic lobe and caudate lobes associated with splenomegaly in almost all patients, and also identified fissure widening, heterogeneity of hepatic parenchyma, irregularity of hepatic contours, presence of peripheral hepatic vessels and periportal fibrosis in almost all patients. CONCLUSION: Hepatic morphological changes are characterized by reduction of the right lobe and enlargement of the caudate and left lobes, and morphological changes in the spleen are characterized by the presence of splenomegaly and siderotic nodules. MRI presents high reproducibility for the evaluation of these changes in patients with chronic infection by Schistosoma mansoni.

Keywords: Parasitic liver disease, Spleen, Schistosomiasis mansoni, Magnetic resonance imaging

The most important diagnostic sign of ureterolithiasis is the direct visualization of the stone within the ureter. However, in some patients with ureterolithiasis stone visualization may be impaired due to stone small size or low attenuation, respiratory artifacts between data acquisitions, low amount of retroperitoneal fat or recent elimination of the stone. In this context, we describe many secondary computed tomography signs of ureteral obstruction that may useful in the diagnosis of inconclusive cases, and also quantify the degree of urinary obstruction.

Keywords: Computed tomography, Acute flank pain, Ureteral stone

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

PURPOSE: To determine the frequency and etiology of intrahepatic calcifications diagnosed on abdominal computed tomography (CT) studies. MATERIALS AND METHODS: A retrospective study of 1,362 consecutive CT scans of the abdomen was carried out to determine the presence of intrahepatic calcifications. The clinical and laboratorial data of all patients with liver calcifications were reviewed in order to establish the etiology of the lesions. RESULTS: Intrahepatic calcifications were found in 3.6% (49/1,362) of the patients, and were predominantly seen in women (57.2%) than in men (42.8%). The population age ranged from 18 to 92 years (mean 59.4 years; median 63.5 years). Calcifications were considered residual and without clinical repercussion in most cases (39/49; 79.5%) whereas in 14.4% (7/49) of the patients calcifications were associated with metastatic disease and in 6.1% (3/49) with cystic lesions. The primary tumors in the seven patients with calcified liver metastases were colon carcinoma (five patients), sarcoma (one patient) and malignant ovarian teratoma (one patient). Two of these patients presented calcifications only after chemotherapy. CONCLUSION: Intrahepatic calcifications are infrequent findings on routine abdominal CT scans (< 5%) and are mostly related to previous inflammatory and/or infectious diseases.

Keywords: Liver, Calcification, Neoplasm, Computed tomography

OBJECTIVE: We developed a protocol to compare the measurements of the anorectal angle in nulliparous and multiparous asymptomatic volunteers in three different situations. SUBJECTS AND METHODS: Defecograms were carried out in 30 women (15 nulliparous and 15 multiparous) from May, 1997 to December, 1998. After rectal administration of texturized barium contrast media, lateral radiographic views of the rectum were obtained at rest, during contraction of the puborectal muscle and during defecation. A repeated measures model was used for the statistical analysis. RESULTS: There were no significant differences between the mean anorectal angles of nulliparous and multiparous volunteers. Measurements were as follows: 92.9° at rest, 78.8° during the contraction of the puborectal muscle and 117.9° during defecation for the nulliparous volunteers; 94.3° at rest, 79.7° during the contraction of the puborectal muscle and 121.4° during defecation for the multiparous volunteers. A significant difference was observed between the anorectal angle measurements at rest, during contraction of the puborectal muscle and during defecation. CONCLUSION: There were no significant differences between the anorectal angle measurements of the two groups of volunteers examined.

Keywords: Defecography, Anus, Rectum, Defecation, Pelvis, Female

OBJECTIVE: To compare both qualitatively and quantitatively six T2-weigthed turbo spin-echo sequences varying the respiratory compensation technique, associating or not fat tissue suppression and using different types of coils. MATERIALS AND METHODS: We performed a prospective study of 71 consecutive patients that were submitted to MRI of the liver using a 1.5T magnet. The six following pulse sequences were used: 1) fat-suppressed respiratory triggered with conventional body coil; 2) breath-hold fat-suppressed with conventional body coil; 3) non-suppressed respiratory triggered with conventional body coil; 4) breath-hold non fat-suppressed with conventional body coil; 5) fat-suppressed respiratory triggered with phased-array multicoil; 6) breath-hold fat-suppressed with phased-array multicoil. Images were analyzed quantitatively by measuring the signal-to-noise ratios and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and the presence of artifacts. RESULTS: The qualitative analysis showed that the mean values obtained with the six sequences were 7.8, 4.6, 7.9, 5.2, 6.7 and 4.6, respectively. The respiratory-triggered sequences were better than the breath-hold sequences in both qualitative and quantitative analysis (p < 0.001). No significant differences in the values of signal-to-noise ratios and in overall image quality rankings were found between the sequences with and without fat suppression (p > 0.05). The sequences using the body coil were similar in terms of image quality (p > 0.05) and better regarding signal-to-noise ratios than those obtained with the phased-array multicoil (p < 0.001). CONCLUSION: Our qualitative and quantitative results suggest that the best MRI sequences for the evaluation of the liver are the sequences with respiratory triggering using a conventional body coil, with or without fat suppression.

Keywords: Magnetic resonance imaging, Liver, Gastrointestinal diagnostic techniques, Imaging techniques

Since the early 1980's several magnetic resonance imaging pulse sequences have been developed in order to determine the optimum imaging technique for the detection and characterization of hepatic lesions. T2-weighted images play an important role in the evaluation of the liver and present equal or greater sensitivity than enhanced computed tomography for the detection of liver lesions. New techniques for obtaining T-2 weighted images have been developed in the attempt to optimize the method. These techniques have improved the image quality by shortening examination time, reducing motion artifacts, and improving contrast-to-noise ratio. The effectiveness of the different techniques (fat suppression, breath-hold, respiratory-triggered and phased-array coils) has been tested in many comparative studies, although the results are controversial. In this article we review the literature and discuss the several T2-weighted image techniques, particularly with regard to sensitivity to detect focal liver lesions.

Keywords: Magnetic resonance imaging, Pulse sequences, Liver tumors, Liver