OBJECTIVE: To evaluate the feasibility of quantifying visceral adipose tissue (VAT) on computed tomography (CT) and magnetic resonance imaging (MRI) scans, using freeware, as well as calculating intraobserver and interobserver reproducibility. MATERIALS AND METHODS: We quantified VAT in patients who underwent abdominal CT and MRI at our institution between 2010 and 2015, with a maximum of three months between the two examinations. A slice acquired at the level of the umbilicus was selected. Segmentation was performed with the region growing algorithm of the freeware employed. Intraobserver and interobserver reproducibility were evaluated, as was the accuracy of MRI in relation to that of CT. RESULTS: Thirty-one patients (14 males and 17 females; mean age of 57 ± 15 years) underwent CT and MRI (mean interval between the examinations, 28 ± 12 days). The interobserver reproducibility was 82% for CT (bias = 1.52 cm²; p = 0.488), 86% for T1-weighted MRI (bias = −4.36 cm²; p = 0.006), and 88% for T2-weighted MRI (bias = −0.52 cm²; p = 0.735). The intraobserver reproducibility was 90% for CT (bias = 0.14 cm²; p = 0.912), 92% for T1-weighted MRI (bias = −3,4 cm²; p = 0.035), and 90% for T2-weighted MRI (bias = −0.30 cm²; p = 0.887). The reproducibility between T1-weighted MRI and T2-weighted MRI was 87% (bias = −0.11 cm²; p = 0.957). In comparison with the accuracy of CT, that of T1-weighted and T2-weighted MRI was 89% and 91%, respectively. CONCLUSION: The program employed can be used in order to quantify VAT on CT, T1-weighted MRI, and T2-weighted MRI scans. Overall, the accuracy of MRI (in comparison with that of CT) appears to be high, as do intraobserver and interobserver reproducibility. However, the quantification of VAT seems to be less reproducible in T1-weighted sequences.

Keywords: Intra-abdominal fat; Image processing, computer-assisted/methods; Tomography, X-ray computed; Magnetic resonance imaging; Reproducibility of results.

OBJECTIVE: To assess the percent agreement between diagnostic imaging modalities for the evaluation of lymphadenopathies in HIV-infected/AIDS patients. MATERIALS AND METHODS: This was an open, comparative, prospective study of diagnostic imaging methods for lymphadenopathy evaluation. We evaluated 30 patients (19 men and 11 women). All underwent ultrasound and computed tomography (CT). Twenty of the patients also underwent magnetic resonance imaging (MRI). We determined the percent agreement between two examiners using the various imaging methods to evaluate lymphadenopathies. RESULTS: CT had the highest percent agreement, at 93.3%, with a kappa coefficient of 0.85, corresponding to 28 of the 30 examinations. When we compared the percent agreement between the two examiners and between CT and ultrasound, examiner 1 had an observed rate of 80.0%, with a kappa of 0.49, corresponding to 24 of the 30 examinations, whereas examiner 2 had a rate of 70.0%, with a kappa of 0.31, corresponding to 21 of the 30 examinations. Between MRI and CT, the percent agreement for examiner 1 was 50.0%, with a kappa of −0.18, corresponding to 10 of the 20 examinations, whereas that for examiner 2 was 85.0%, with a kappa of 0.69, corresponding to 17 of the 20 examinations. For MRI and ultrasound, examiner 1 had a percent agreement of 70.0%, with a kappa of 0.20, corresponding to 14 of the 20 examinations, and examiner 2 had a percent agreement of 75.0%, with a kappa of 0.38, corresponding to 15 of the 20 examinations. CONCLUSION: This study indicates that intermethod agreement is highly dependent on the way in which the research is conducted, rather than on the level of experience of the examiner.

Keywords: HIV; Acquired immunodeficiency syndrome; Lymphadenopathy; Ultrasonography; Tomography, X-ray computed; Magnetic resonance imaging..

OBJECTIVE: To evaluate the computed tomography characteristics of patients admitted with clinical suspicion of acute adrenal hemorrhage at three centers over a 3-year period and in whom that diagnosis was ultimately confirmed. MATERIALS AND METHODS: This was a retrospective analysis of computed tomography findings in patients with suspected acute adrenal hemorrhage. We included only those cases in which the diagnosis was confirmed. Patients with aortic rupture and retroperitoneal hemorrhage were excluded. The images were analyzed by an experienced radiologist and by two radiology residents. RESULTS: Six cases of unilateral adrenal hemorrhage (three on the left and three on the right) were analyzed. On computed tomography, each appeared as a rounded, oval mass altering the usual anatomy of the adrenal gland. The maximum diameter was 12.2 cm, and attenuation ranged from 45 to 70 HU. There was no appreciable contrast enhancement. No calcifications were observed. CONCLUSION: Adrenal hemorrhage, albeit rare, is potentially fatal. Early diagnosis is essential. Therefore, recognition of the possible presentations of these lesions by radiologists may help prevent hemorrhage from progressing to adrenal insufficiency and death.

Keywords: Adrenal glands; Hemorrhage; Tomography, X-ray computed.

OBJECTIVE: To evaluate the frequency and types of upper cervical spine injuries in asymptomatic elderly patients undergoing computed tomography (CT) for the investigation of minor head trauma. MATERIALS AND METHODS: This was a prospective study of 2613 asymptomatic elderly patients with minor head trauma seen between January 2015 and December 2016. We adopted a dedicated head CT protocol that included the C1–C2 region. RESULTS: Of the 2613 patients analyzed, 33 (1.26%) had upper cervical spine injuries, corresponding to 8.37% of the 394 patients with trauma-related findings. Of those 33 patients, 6 had C1 fractures and 27 had C2 fractures. The use of 16- and 128-slice scanners increased the CT dose by 25.0% and 23.7%, respectively. CONCLUSION: Inclusion of the C1–C2 region in head CT scans allowed us to identify upper cervical spine injuries in 1.26% of asymptomatic elderly patients with minor head trauma. The protocol evaluated helps detect potentially life-threatening injuries and could be adopted for routine use in elderly individuals with minor head trauma.

Keywords: Craniocerebral trauma; Aged; Aged, 80 and over; Spinal injuries/diagnosis; Cervical vertebrae/injuries; Tomography, X-ray computed.

OBJECTIVE: To determine whether ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography performed immediately after percutaneous ablation (_iPA¹⁸F-FDG PET/CT) is useful in evaluating the outcomes of the procedure. MATERIALS AND METHODS: This was a retrospective study of 20 patients (13 males, 7 females; mean age, 65.8 ± 12.1 years) submitted to percutaneous ablation of metastases. All of the lesions treated had shown focal uptake on a ¹⁸F-FDG PET/CT scan obtained at baseline. The primary tumors were mainly colorectal cancer (in 45%) or lung cancer (in 40%). _iPA¹⁸F-FDG PET/CT was performed to identify any residual viable tumor cells. The treatment was considered a success (no viable tumor cells present) if no uptake of ¹⁸F-FDG was noted on the _iPA¹⁸F-FDG PET/CT scan. RESULTS: Twenty-six lesions were submitted to percutaneous ablation with either cryoablation (n = 7) or radiofrequency ablation (n = 19). The mean lesion diameter was 2.52 ± 1.49 cm. For the detection of viable tumor cells, _iPA¹⁸F-FDG PET/CT had a sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 66.7%, 95%, 88.5%, 80%, and 90.5%, respectively. There was a significant correlation between the _iPA¹⁸F-FDG PET/CT findings and the results of the follow-up studies (kappa = 0.66; p < 0.01). CONCLUSION: _iPA¹⁸F-FDG PET/CT studies appear to constitute a useful means of evaluating the outcomes of percutaneous ablation. By detecting residual viable tumor cells, this strategy might allow early re-intervention, thus reducing morbidity. Studies involving larger numbers of patients are needed in order to confirm our findings.

Keywords: Fluorodeoxyglucose F18; Positron-emission tomography/methods; Tomography, X-ray computed/methods; Ablation techniques; Cryosurgery/methods; Radiofrequency ablation.

OBJECTIVE: To determine whether an interim ¹⁸F-fluoride positron-emission tomography/computed tomography (PET/CT) study performed after the third cycle of radium-223 dichloride (²²³RaCl₂) therapy is able to identify patients that will not respond to treatment. MATERIALS AND METHODS: We retrospectively reviewed 34 histologically confirmed cases of hormone-refractory prostate cancer with bone metastasis in patients submitted to ²²³RaCl₂ therapy. All of the patients underwent baseline and interim ¹⁸F-fluoride PET/CT studies. The interim study was performed immediately prior to the fourth cycle of ²²³RaCl₂. The skeletal tumor burden—expressed as the total lesion fluoride uptake above a maximum standardized uptake value of 10 (TLF₁₀)—was calculated for the baseline and the interim studies. The percent change in TLF₁₀ between the baseline and interim studies (%TFL₁₀) was calculated as follows: %TFL₁₀ = interim TLF₁₀ − baseline TLF₁₀ / baseline TLF₁₀. End points were overall survival, progression-free survival, and skeletal-related events. RESULTS: The mean age of the patients was 72.4 ± 10.2 years (range, 43.3–88.8 years). The %TLF₁₀ was not able to predict overall survival (p = 0.6320; hazard ratio [HR] = 0.753; 95% confidence interval [CI]: 0.236–2.401), progression-free survival (p = 0.5908; HR = 1.248; 95% CI: 0.557–2.797) nor time to a bone event (p = 0.5114; HR = 1.588; 95% CI: 0.399–6.312). CONCLUSION: The skeletal tumor burden on an interim ¹⁸F-fluoride PET/CT, performed after three cycles of ²²³RaCl₂, is not able to predict overall survival, progression-free survival, or time to bone event, and should not be performed to monitor response at this time.

Keywords: Sodium fluoride; Positron-emission tomography/methods; Tomography, X-ray computed/methods; Prostatic neoplasms; Radium-223; Bone neoplasms/diagnostic imaging; Tumor burden.

Most tumors of the biliary tract are too small to have specific imaging characteristics or for percutaneous puncture to provide sufficient material for diagnosis. Percutaneous transhepatic biliary drainage, in addition to being a well-established technique in the treatment of obstructive jaundice, provides adequate access for sampling obstructive lesions. In cases of biliary lesions, percutaneous transhepatic biopsy of the biliary tract has proven to be a useful diagnostic technique, with a reported accuracy of over 90% at some referral centers.

Keywords: Bile duct neoplasms; Biliary tract; Biopsy/methods; Biopsy, needle/methods; Cholangiography.

Ductal carcinoma in situ (DCIS) is a precursor mammary lesion whose malignant cells do not extend beyond the basement membrane and presents a risk of progression to malignant disease. Its early detection increased with screening mammography. The objective of this study was to review the literature on the main presentations of DCIS on magnetic resonance imaging (MRI), through searches of the Medline/PubMed, Latin-American and Caribbean Center on Health Sciences Information (Lilacs), and Scientific Electronic Library Online (SciELO) databases. DCIS can occur in its pure form or in conjunction with invasive disease, in the same lesion, in different foci, or in the contralateral breast. MRI has a high sensitivity for the detection of pure DCIS, being able to identify the non-calcified component, and its accuracy increases with the nuclear grade of the lesion. The most common pattern of presentation is non-nodular enhancement; heterogeneous internal structures; a kinetic curve showing washout or plateau enhancement; segmental distribution; and restricted diffusion. MRI plays an important role in the detection of DCIS, especially in the evaluation of its extent, contributing to more reliable surgical excision and reducing local recurrence.

Keywords: Radiology; Carcinoma, intraductal, noninfiltrating; Magnetic resonance imaging; Breast neoplasms.

Focal bone lesions are not uncommon findings in the daily practice of radiology. Therefore, it is essential to differentiate between lesions with aggressive, malignant potential that require action and those that have no clinical significance, many of which are variants or benign lesions, sometimes self-limited and related to reactive processes. In some cases, a diagnostic error can have catastrophic results. For example, a biopsy performed in a patient with myositis ossificans can lead to an incorrect diagnosis of sarcomatous lesions and consequently to mutilating surgical procedures. The present study reviews the main radiological aspects of the lesions that are most commonly seen in daily practice and have the potential to be confused with aggressive, malignant bone processes. We also illustrate these entities by presenting cases seen at our institution.

Keywords: Bone diseases; Muscular diseases; Diagnostic imaging; Myositis ossificans; Bone neoplasms.

Hearing disorders are usually unilateral and are more common in women. They can be congenital or acquired, and hearing loss is categorized as sensorineural, conductive, or mixed. The onset of hearing loss can be progressive or sudden, and it is a common reason for seeking medical attention. In this context, computed tomography and magnetic resonance imaging have assumed critical roles in the search for an etiological diagnosis and in guiding the therapeutic approach. In this pictorial essay, we illustrate the common causes of hearing loss, discussing the possible differential diagnoses and highlighting the most relevant imaging findings.

Keywords: Hearing loss; Head and neck neoplasms; Neuroimaging; Tomography, X-ray computed; Magnetic resonance imaging.