The combination of positron emission tomography (PET) with magnetic resonance imaging (MRI) has been the subject of several studies in recent years. Positron emission tomography is the most sensitive and specific imaging modality in the detection of metabolic changes, but presents limited spatial resolution. On the other hand, MRI presents a significant spatial resolution, besides evaluating soft tissues signal intensity with excellent contrast resolution. The present iconographic essay is aimed at demonstrating the potential clinical application of PET/MRI coregistration. The studies were performed in a dedicated PET unit with 18F-fluorodeoxyglucose (FDG) as radiopharmaceutical and coregistered with 1.5 T or 3 T brain MRI. The brain images fusion software presents an already well-established accuracy, so a significant synergy between a functional PET study and an excellent MRI anatomical detail is achieved. The most attractive clinical applications of this approach are the following: epileptogenic zone assessment in patients refractory to drug therapy, identification of patients with cognitive impairment at higher risk for progression to dementia and differentiation of dementias and Parkinsonian syndromes.

Keywords: Fluorodeoxyglucose, FDG, Positron emission tomography, PET, Magnetic resonance imaging, Fusion, Clinical neurology

Hepatic hemangioma is frequently asymptomatic, and bleeding is rare, even in cases of large lesions. The authors report the case of a 31-year-old female patient presenting with acute abdominal pain, whose imaging studies have demonstrated hematoma in the left hepatic lobe associated with hemoperitoneum. The patient was submitted to left hepatectomy, with a final histopathological diagnosis of cavernous hemangioma.

Keywords: Hepatic hemangioma, Hemoperitoneum, Computed tomography, Acute abdomen

OBJECTIVE: To establish the role of MRI T2-weighted sequences in the differentiation between simple cysts and hepatic hemangiomas. MATERIALS AND METHODS: A double-blinded, prospective, observational, cross-sectional study evaluated 52 patients with 91 hepatic lesions (34 simple cysts and 57 hemangiomas) submitted to abdominal magnetic resonance imaging. The combined analysis of all sequences was considered as the golden-standard. TSE sequences with long echo trains and b-FFE sequences were subjectively analyzed by two independent observers for differentiating cysts from hemangiomas. The kappa test (κ) was utilized in the analysis of the methods accuracy and inter- and intra-observer agreement (p < 0.05*). RESULTS: Cysts and hemangiomas dimensions ranged respectively between 0.5 and 6.5 cm (mean = 1.89 cm), and 0.8 and 11 cm (mean = 2.62 cm). The analysis of the sequences with long-TE and the golden-standard demonstrated a non-statistically significant agreement (κ: 0.00-0.10). The agreement between the evaluation of the b-FFE sequence and the golden-standard ranged from substantial (κ: 0.62-0.71) to almost perfect (κ: 0.86) for both observers. The inter- and intra-observer agreement for the b-FFE sequence ranged from substantial (κ: 0.62-0.70) to almost perfect (κ: 0.85-0.91). CONCLUSION: T2-weighted images acquired with the b-FFE technique present a high accuracy and reproducibility in the differentiation between cysts and hepatic hemangiomas.

Keywords: Liver, Cyst, Hemangioma, Magnetic resonance imaging

In order to evaluate atypical aspects of hepatic hemangiomas at ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI), we have retrospectively analyzed 300 cases of patients diagnosed with hepatic hemangiomas by means of combined imaging studies, clinical follow-up and/or biopsy results. Based on this analysis we have selected those cases with atypical findings at one or more imaging methods or those presenting an unusual evolution such as: hypoechoic nodules at US; giant, heterogeneous hemangiomas; rapidly filling hemangiomas; calcified hemangiomas; pedunculated hemangiomas; hypointense hemangiomas at T2-weighted images; causing perfusion defect; with central scar simulating focal nodular hyperplasia; hemangiomas with adjacent abnormalities such as arterial-portal venous shunt and capsular retraction as well as hemangiomas enlarging over time. The hepatic hemangioma is the most common benign tumor affecting the liver and usually presents typical aspect. However, atypical findings should be known aiming at supporting diagnosis guidance and clinical decisions.

Keywords: Hemangioma, Liver, Atypical findings, Ultrasound, Computed tomography, Magnetic resonance imaging

Hemangiomas are the most common benign tumors of the liver, occurring in all age groups, and more frequently in adults. The vast majority of hemangiomas are small, asymptomatic, and are incidentally discovered. Larger lesions may eventually produce symptoms. The sonographic aspect of these tumors varies, the lesions being typically small, well defined and hyperechoic. In this study the authors review clinical and sonographic features of hemangiomas, highlighting the clinical significance of such features to be taken into consideration in the treatment of affected patients.

Keywords: Hemangioma, Liver, Ultrasound

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

Hemangiomas are benign hepatic tumors that in most cases require no surgical excision if correctly identified. Ultrasound (US) usually shows hyperechogenic tumors although some unusual hypoechogenic hemangiomas have also been described. Fifteen patients with hypoechogenic hemangiomas, identified in a period of approximately four years, were evaluated prospectively. As the US findings of these hemangiomas were atypical, the final diagnosis was established after a combined analysis of US and helical computed tomography (helical-CT) findings. Helical-CT showed centripetal enhancement after administration of intravenous iodinated contrast media in all lesions. The levels of carcinoembrionic antigen and alpha-fetoprotein were measured in all patients who were also submitted to endoscopy and colonoscopy (or double contrast enema). No abnormalities were found in any of these tests. Additionally, US and helical-CT examinations were performed 8 to 12 months after the initial investigation in all patients, and no changes were seen in the appearance and dimensions of the lesions. There was associated steatosis in 14 of the 15 patients with hypoechogenic hemangiomas. The authors concluded that atypical hypoechogenic hemangiomas occur mainly in patients with steatosis and only occasionally in patients with nonsteatotic liver. In these atypical cases complementary imaging and biochemical studies, and follow-up tests are necessary to establish an accurate diagnosis.

Keywords: Liver, Hemangioma, Hypoechogenic hemangioma, Ultrasonography

We report the clinical and imaging findings of a patient with a symptomatic vertebral hemangioma treated with radiotherapy alone. There was partial relief of the pain 3 months after radiotherapy. We recommend a total dose of 40 Gy at 2 Gy per fraction. A review of literature is also presented.

Keywords: Hemangioma, Radiotherapy, Spine

The authors present a list of recommendations on the utilization of 18F-FDG PET/CT in oncology for the diagnosis, staging and detection of cancer, as well as in the follow-up of the disease progression and possible recurrence. The recommendations were based on the analysis of controlled studies and a systematic review of the literature including both retrospective and prospective studies regarding the clinical usefulness and the impact of 18F-FDG PET/CT on the management of cancer patients. 18F-FDG PET/CT should be utilized as a supplement to other conventional imaging methods such as computed tomography and magnetic resonance imaging. Positive results suggesting changes in the clinical management should be confirmed by histopathological studies. 18F-FDG PET should be utilized in the diagnosis and appropriate clinical management of cancer involving the respiratory system, head and neck, digestive system, breast, genital organs, thyroid, central nervous system, besides melanomas, lymphomas and occult primary tumors.

Keywords: FDG-PET; Oncology; Diagnosis; Clinical indications.

Breast hemangioma is a rare benign tumor that presents either absent or low 18F-fluoro-2-deoxy-D-glucose (FDG) uptake at positron emission tomography (PET). The authors report the case of a breast nodule pathologically compatible with hemangioma in a woman whose PET-scan has demonstrated increased FDG uptake (simulating a malignant tumor). A brief review of factors leading to false positive and false negative PET results is also undertaken.

Keywords: PET/CT; FDG-18F; Hemangioma; Breast.

OBJECTIVE: To evaluate the accuracy and cost-effectiveness of metabolic staging (MS) with FDG-PET as compared with the conventional staging (CS) strategy in the preoperative staging of non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: A total of 95 patients with initial diagnosis of NSCLC were staged before undergoing treatment. The MS and CS results were compared with regard to treatment definition and incidence of futile thoracotomies with both strategies. RESULTS: Metabolic staging with FDG-PET upstaged 48.4% and downstaged 5.3% of the patients, and would lead to change in the treatment of 41% of cases. Thoracotomy was considered as futile in 47% of the patients with CS, and in 19% of the patients with MS. The cost of futile thoracotomies in eight patients with MS was R$ 79,720, while in 31 patients with CS it would be R$ 308,915. Just such saving in costs would be more than enough to cover the costs of all FDG-PETs (R$ 126,350) or FDG-PET/CTs (R$ 193,515) for the 95 patients. CONCLUSION: The metabolic staging with FDG-PET is more accurate than CS in patients with NSCLC. Both FDG-PET and FDG-PET/CT are cost-effective methods and their utilization is economically justifiable in the Brazilian public health system.

Keywords: Non-small cell lung cancer; FDG-PET; Staging; Cost-effectiveness.

OBJECTIVE: To evaluate the role of PET/CT in the approach to patients with head and neck cancer. MATERIALS AND METHODS: Retrospective study of medical records and PET/CT images of 63 patients with head and neck cancer. RESULTS: Alterations were observed in 76% of the cases. Out of these cases, 7 (11%) were considered as false-positive, with SUV < 5.0. PET/CT demonstrated negative results in 15 cases (24%). Among the 14 cases where the method was utilized for staging, 3 (22%) had their stages changed. CONCLUSION: PET/CT has shown to be of potential value in the routine evaluation of patients with head and neck cancer, but further studies of a higher number of cases are required to define a protocol for utilization of the method.

Keywords: Emission computed tomography; Fluorodeoxyglucose 18F; Head and neck neoplasms; Neoplasm staging; Squamous cell carcinoma.

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.

Keywords: Hemangioma; Cysts; Magnetic resonance imaging; Prevalence; Liver.

OBJECTIVE: The present article is aimed at reporting the author's experience with transcatheter arterial embolization using a lipiodol-ethanol mixture in three cases of unresectable symptomatic giant hepatic hemangiomas. MATERIALS AND METHODS: The cases of three patients with giant unresectable symptomatic hepatic hemangiomas embolized in the period 2009-2010 were retrospectively reviewed. In all the cases, transarterial embolization was performed with an ethanol-lipiodol mixture. RESULTS: Symptoms regression and quality of life improvement were observed in all the cases. No complications were observed and all the patients were discharged within 12 hours after the procedure. CONCLUSION: Transcatheter arterial embolization using ethanol mixed with lipiodol was a safe and effective treatment for symptomatic giant hepatic hemangiomas in this small series of patients.

Keywords: Hemangioma; Therapeutic embolization; Ethanol; Ethiodized oil.

Abdominal vascular syndromes are rare diseases. Although such syndromes vary widely in terms of symptoms and etiologies, certain imaging findings are characteristic. Depending on their etiology, they can be categorized as congenital—including blue rubber bleb nevus syndrome, Klippel-Trenaunay syndrome, and hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)—or compressive—including "nutcracker" syndrome, median arcuate ligament syndrome, Cockett syndrome (also known as May-Thurner syndrome), and superior mesenteric artery syndrome. In this article, we aimed to illustrate imaging findings that are characteristic of these syndromes, through studies conducted at our institution, as well as to perform a brief review of the literature on this topic.

Keywords: Gastrointestinal tract; Venous thrombosis; Arteriovenous fistula; Hemangioma.