OBJECTIVE: To determine the rates of diagnostic success and complications of computed tomography (CT)-guided percutaneous biopsy of bone lesions suspected for malignancy. MATERIALS AND METHODS: Retrospective study including 186 cases of CT-guided percutaneous biopsies of bone lesions in the period from January, 2010 to December, 2012. All the specimens were obtained with 8-10 gauge needles. The following data were collected: demographics, previous history of malignancy, data related to the lesion, to the procedure, and to histological results. RESULTS: Most patients were women (57%), and the mean age was 53.0 ± 16.4 years. In 139 cases (74.6%), there was diagnostic suspicion of metastasis and the most common primary tumors were breast (32.1%) and prostate (11.8%). The bones most commonly involved were spine (36.0%), hip (32.8%) and long bones (18.3%). Complications occurred in only three cases (1.6%) including bone fracture, paresthesia with functional impairment, and needle breakage requiring surgical removal. The specimens collected from 183 lesions (98.4%) were considered appropriate for diagnosis. Malignant results were more frequently found in patients who had a suspected secondary lesion and history of known malignancy (p < 0.001), and in patients who underwent PET/CT-guided procedures (p = 0.011). CONCLUSION: CT-guided percutaneous biopsy is a safe and effective procedure for the diagnosis of suspicious bone lesions.

Keywords: Bone neoplasms; Needle biopsy; Computed tomography; Interventional radiology; Complications.

OBJECTIVE: This article presents a way to obtain estimates of dose in patients submitted to radiotherapy with basis on the analysis of regions of interest on nuclear medicine images. MATERIALS AND METHODS: A software called DoRadIo (Dosimetria das Radiações Ionizantes [Ionizing Radiation Dosimetry]) was developed to receive information about source organs and target organs, generating graphical and numerical results. The nuclear medicine images utilized in the present study were obtained from catalogs provided by medical physicists. The simulations were performed with computational exposure models consisting of voxel phantoms coupled with the Monte Carlo EGSnrc code. The software was developed with the Microsoft Visual Studio 2010 Service Pack and the project template Windows Presentation Foundation for C# programming language. RESULTS: With the mentioned tools, the authors obtained the file for optimization of Monte Carlo simulations using the EGSnrc; organization and compaction of dosimetry results with all radioactive sources; selection of regions of interest; evaluation of grayscale intensity in regions of interest; the file of weighted sources; and, finally, all the charts and numerical results. CONCLUSION: The user interface may be adapted for use in clinical nuclear medicine as a computer-aided tool to estimate the administered activity.

Keywords: Nuclear medicine; Biokinetic distribution; Dosimetric evaluations; Administered activity.

OBJECTIVE: To analyze anatomical variations associated with celiac plexus complex by means of computed tomography simulation, assessing the risk for organ injury as the transcrural technique is utilized. MATERIALS AND METHODS: One hundred eight transaxial computed tomography images of abdomen were analyzed. The aortic-vertebral, celiac trunk (CeT)-vertebral, CeT-aortic and celiac-aortic-vertebral topographical relationships were recorded. Two needle insertion pathways were drawn on each of the images, at right and left, 9 cm and 4.5 cm away from the midline. Transfixed vital organs and gender-related associations were recorded. RESULTS: Aortic-vertebral - 45.37% at left and 54.62% in the middle; CeT-vertebral - T12, 36.11%; T12-L1, 32.4%; L1, 27.77%; T11-T12, 2.77%; CeT-aortic - 53.7% at left and 46.3% in the middle; celiac-aortic-vertebral - L-l, 22.22%; M-m, 23.15%; L-m, 31.48%; M-l, 23.15%. Neither correspondence on the right side nor significant gender-related associations were observed. CONCLUSION: Considering the wide range of abdominal anatomical variations and the characteristics of needle insertion pathways, celiac plexus block should not be standardized. Imaging should be performed prior to the procedure in order to reduce the risks for injuries or for negative outcomes to patients. Gender-related anatomical variations involved in celiac plexus block should be more deeply investigated, since few studies have addressed the subject.

Keywords: Celiac plexus block; Transcrural pathway; Computed tomography; Anatomy.

OBJECTIVE: Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). MATERIALS AND METHODS: The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. RESULTS: No significant difference was observed in the values for weighted air kerma index (C_W), but the differences were relevant in values for volumetric air kerma index (C_VOL), air kerma-length product (P_KL,CT) and effective dose. CONCLUSION: Only the C_W values were lower than the DRL, suggesting that dose optimization might not be necessary. However, P_KL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans.

Keywords: Pediatric computed tomography scans; Dosimetric quantities; Weighted dose index; Volumetric air kerma index; Air kermalength product.

Multiparametric MR (mpMR) imaging is rapidly evolving into the mainstay in prostate cancer (PCa) imaging. Generally, the examination consists of T2-weighted sequences, diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) evaluation, and less often proton MR spectroscopy imaging (MRSI). Those functional techniques are related to biological properties of the tumor, so that DWI correlates to cellularity and Gleason scores, DCE correlates to angiogenesis, and MRSI correlates to cell membrane turnover. The combined use of those techniques enhances the diagnostic confidence and allows for better characterization of PCa. The present article reviews and illustrates the technical aspects and clinical applications of each component of mpMR imaging, in a practical approach from the urological standpoint.

Keywords: Prostate cancer; Magnetic resonance imaging; Diffusion-weighted imaging; Dynamic contrast enhancement.

The characterization of focal liver lesions is very important. Magnetic resonance imaging is considered the best imaging method for evaluating such lesions, but does not allow for the diagnosis in all cases. The use of hepatobiliary contrast agents increases the diagnostic accuracy of magnetic resonance imaging and reduces the number of non-specific liver lesions. The main indications for the method include: differentiation between focal nodular hyperplasia and adenoma; characterization of hepatocellular carcinomas in cirrhotic patients; detection of small liver metastases; evaluation of biliary anatomy; and characterization of postoperative biliary fistulas. The use of hepatobiliary contrast agents may reduce the need for invasive diagnostic procedures and further investigations with other imaging methods, besides the need for imaging follow-up.

Keywords: Focal hepatic lesions; Hepatobiliary contrast; Magnetic resonance imaging.

Most malignant liver tumors are represented by hepatocellular carcinoma and cholangiocarcinoma; however a variety of other uncommon hepatic lesions might also be found. Common lesions such as hemangioma, focal nodular hyperplasia and metastases are well known and have already been extensively documented in the literature. The diagnosis of typical hepatic lesions may be done with some reliability by means of several imaging methods; on the other hand, uncommon lesions normally represent a diagnostic challenge for the radiologist. In this first part of the study, the authors will approach five uncommon liver tumors - angiosarcoma, angiomyolipoma, cystadenoma/biliary carcinoma, epithelioid hemangioendothelioma, and fibrolamellar hepatocellular carcinoma -, describing their main characteristics and image findings with focus on computed tomography and magnetic resonance imaging.

Keywords: Neoplasms; Liver; Atypical; Computed tomography; Magnetic resonance imaging.

Acute tracheobronchitis is a rare manifestation of invasive aspergillosis, generally occurring in severely immunocompromised patients. The authors report the case of a patient presenting with this condition after bone-marrow transplantation, with emphasis on tomographic findings.

Keywords: Aspergillosis; Tracheal disease; Immunocompromised host.

The authors report the case of an elderly woman assessed for dyspnea and right costal margin pain, whose chest radiography demonstrated opacity simulating pulmonary lesion, and computed tomography revealed the vascular origin of the condition. Acute aortic syndrome due to ruptured atheromatous plaque penetrating through the elastic lamina in association with aortic hematoma and aneurysm is a relevant differential diagnosis to be considered in these cases.

Keywords: Aorta; Aortic arch; Computed tomography.

The involvement of the retroperitoneum by endometriosis occurs only sporadically. In the present report, emphasis will be given to the magnetic resonance imaging findings which raised the diagnostic suspicion of periureteral lesion in a patient undergoing tamoxifen therapy, presenting with left upper quadrant pain and hydronephrosis. Histopathological findings obtained by means of computed tomography-guided percutaneous biopsy revealed the diagnosis of periureteral endometriosis.

Keywords: Endometriosis; Ureter; Tamoxifen; Magnetic resonance imaging; Biopsy.

The authors report the case of a plexiform neurofibroma located in the pelvis, affecting the bladder, prostate and spine (lumbar/sacral), followed-up for three years and six months. Surgical removal was contraindicated and the patient underwent biannual clinical and radiological follow-up that did not demonstrate any tumor increase. The clinical manifestations of neurofibromatosis type 1 are variable, and the medical team should be attentive to further investigations, considering possible unexpected rare findings. Large pelvic masses may correspond to plexiform neurofibromas, so the diagnostic hypothesis of neurofibromatosis should be taken into consideration.

Keywords: Neurofibromatosis type 1; Plexiform neurofibroma; Pelvis.