Multimodality fusion imaging in abdominal and pelvic malignancies: current applications and future perspectives.

Medicine is evolving toward personalized care and this development entails the integration, amalgamation, and synchronized analysis of data from multiple sources. Multimodality fusion imaging refers to the simultaneous visualization of spatially aligned and juxtaposed medical images obtained by two or more image modalities. PET/MRI scanners and MMFI platforms are able to improve the diagnostic workflow in oncologic patients and provide exquisite images that aid physicians in the molecular profiling and characterization of tissues. Advanced navigation platforms involving real-time ultrasound are promising tools for guiding personalized and tailored mini-invasive interventional procedures on technically challenging targets. The main objective of the present essay was to describe the current applications and future perspectives of multimodality fusion imaging for both diagnostic and interventional purposes in the field of abdominal and pelvic malignancies. We also outlined the technical differences between fusion imaging achieved by means of simultaneous bimodal acquisition (i.e., integrated PET/MRI scanners), retrospective co-registration, and multimodality fusion imaging involving ultrafast or real-time imaging modalities.

Value of bimodal (18)F-choline-PET/MRI and trimodal (18)F-choline-PET/MRI/TRUS for the assessment of prostate cancer recurrence after radiation therapy and radical prostatectomy.

Between 27% and 53% of all patients who undergo radical prostatectomy (RP) or radiation therapy (RT) as the first-line treatment of prostate cancer (PCa) develop a biochemical recurrence. Imaging plays a pivotal role in restaging by helping to distinguish between local relapse and metastatic disease (i.e., lymph-node and skeletal metastases). At present, the most promising tools for assessing PCa patients with biochemical recurrence are multiparametric magnetic resonance imaging (mpMRI) and positron emission tomography (PET)/computed tomography (CT) with radio-labeled choline derivatives. The main advantage of mpMRI is its high diagnostic accuracy in detecting local recurrence, while choline-PET/CT is able to identify lymph-node metastases when they are not suspicious on morphological imaging. The most recent advances in the field of fusion imaging have shown that multimodal co-registration, synchronized navigation, and combined interpretation are more valuable than the individual; separate assessment offered by different diagnostic techniques. The objective of the present essay was to describe the value of bimodal choline-PET/mpMRI fusion imaging and trimodal choline-PET/mpMRI/transrectal ultrasound (TRUS) in the assessment of PCa recurrence after RP and RT. Bimodal choline-PET/mpMRI fusion imaging allows morphological, functional, and metabolic information to be combined, thereby overcoming the limitations of each separate imaging modality. In addition, trimodal real-time choline-PET/mpMRI/TRUS fusion imaging may be useful for the planning and real-time guidance of biopsy procedures in order to obtain histological confirmation of the local recurrence.

Extrusion of the medial meniscus in knee osteoarthritis assessed with a rotating clino-orthostatic permanent-magnet MRI scanner.

PURPOSE: The objectives of this study were to assess the influence of weight-bearing on tibiofemoral osteoarthritis, including medial meniscal extrusion, by using a low-field (0.25 T) rotating clino-orthostatic permanent-magnet magnetic resonance (MR) scanner, and to analyse correlations of medial meniscal extrusion with the patient's Kellgren-Lawrence score, body mass index, and all the osteoarthritis features of the WORMS scoring system. MATERIALS AND METHODS: Twenty-six patients (69.2% women and 30.8% men; mean age 67 ± 9.7 years) with medial tibiofemoral knee osteoarthritis were prospectively enrolled and MR sequences were acquired in both clino- and orthostatic position. MR images were assessed by two independent radiologists, according to the WORMS scale. Medial meniscal extrusion was measured and its clino-orthostatic difference (∆MME) was calculated. RESULTS: Intra- and inter-observer agreement of the WORMS Global Score readings was high by Cohen's K test (>0.81). No significant clino-orthostatic changes in the scoring parameters of the medial tibiofemoral joint were shown by Wilcoxon's test. Medial meniscal extrusion measured on orthostatic images was significantly higher than that measured in clinostatic position (p < 0.0001). At univariate analysis, the Kellgren-Lawrence score, WORMS Global Score, cartilage loss, meniscal damage, and osteophytes were significantly correlated to ∆MME (p < 0.005). Using a multiple regression model, tibiofemoral cartilage loss was found to correlate independently with ∆MME (p = 0.0499). CONCLUSIONS: Medial meniscal extrusion, evaluated with an open-configuration, rotating MR scanner, increased from the clinostatic to the orthostatic position. ∆MME, a new meniscal parameter, correlated with several important features of medial tibiofemoral osteoarthritis.

Value of fused 18F-Choline-PET/MRI to evaluate prostate cancer relapse in patients showing biochemical recurrence after EBRT: preliminary results.

PURPOSE: We compared the accuracy of (18)F-Choline-PET/MRI with that of multiparametric MRI (mMRI), (18)F-Choline-PET/CT, (18)F-Fluoride-PET/CT, and contrast-enhanced CT (CeCT) in detecting relapse in patients with suspected relapse of prostate cancer (PC) after external beam radiotherapy (EBRT). We assessed the association between standard uptake value (SUV) and apparent diffusion coefficient (ADC). METHODS: We evaluated 21 patients with biochemical relapse after EBRT. Patients underwent (18)F-Choline-PET/contrast-enhanced (Ce)CT, (18)F-Fluoride-PET/CT, and mMRI. Imaging coregistration of PET and mMRI was performed. RESULTS: (18)F-Choline-PET/MRI was positive in 18/21 patients, with a detection rate (DR) of 86%. DRs of (18)F-Choline-PET/CT, CeCT, and mMRI were 76%, 43%, and 81%, respectively. In terms of DR the only significant difference was between (18)F-Choline-PET/MRI and CeCT. On lesion-based analysis, the accuracy of (18)F-Choline-PET/MRI, (18)F-Choline-PET/CT, CeCT, and mMRI was 99%, 95%, 70%, and 85%, respectively. Accuracy, sensitivity, and NPV of (18)F-Choline-PET/MRI were significantly higher than those of both mMRI and CeCT. On whole-body assessment of bone metastases, the sensitivity of (18)F-Choline-PET/CT and (18)F-Fluoride-PET/CT was significantly higher than that of CeCT. Regarding local and lymph node relapse, we found a significant inverse correlation between ADC and SUV-max. CONCLUSION: (18)F-Choline-PET/MRI is a promising technique in detecting PC relapse.

Diagnostic accuracy of chest radiography for the diagnosis of tuberculosis (TB) and its role in the detection of latent TB infection: a systematic review.

In this systematic review we evaluate the role of chest radiography (CXR) in the diagnostic flow chart for tuberculosis (TB) infection, focusing on latent TB infection (LTBI) in patients requiring medical treatment with biological drugs. In recent findings, patients scheduled for immunomodulatory therapy with biologic drugs are a group at risk of TB reactivation and, in such patients, detection of LTBI is of great importance. CXR for diagnosis of pulmonary TB has good sensitivity, but poor specificity. Radiographic diagnosis of active disease can only be reliably made on the basis of temporal evolution of pulmonary lesions. In vivo tuberculin skin test and ex vivo interferon-γ release assays are designed to identify development of an adaptive immune response, but not necessarily LTBI. Computed tomography (CT) is able to distinguish active from inactive disease. CT is considered a complementary imaging modality to CXR in the screening procedure to detect past and LTBI infection in specific subgroups of patients who have increased risk for TB reactivation, including those scheduled for medical treatment with biological drugs.

Advantages of percutaneous abdominal biopsy under PET-CT/ultrasound fusion imaging guidance: a pictorial essay.

Positron emission tomography (PET) is a functional imaging technique that can investigate the metabolic characteristics of tissues. Currently, PET images are acquired and co-registered with a computed tomography (CT) scan (PET-CT), which is employed for correction of attenuation and anatomical localization. In spite of the high negative predictive value of PET, false-positive results may occur; indeed, Fluorine 18 ((18)F)-fluorodeoxyglucose ((18)F-FDG) uptake is not specific to cancer. As (18)F-FDG uptake may also be seen in non-malignant infectious or inflammatory processes, FDG-avid lesions may necessitate biopsy to confirm or rule out malignancy. However, some PET-positive lesions may have little or no correlative ultrasound (US) and/or CT findings (i.e., low conspicuity on morphological imaging). Since it is not possible to perform biopsy under PET guidance alone, owing to intrinsic technical limitations, PET information has to be integrated into a CT- or US-guided biopsy procedure (multimodal US/PET-CT fusion imaging). The purpose of this pictorial essay is to describe the technique of multimodal imaging fusion between real-time US and PET/CT, and to provide an overview of the clinical settings in which this multimodal integration may be useful in guiding biopsy procedures in PET-positive abdominal lesions.

Computed tomography enterography and 18F-FDG PET/CT features of primary signet ring cell carcinoma of the small bowel in a patient with Crohn's disease.

We report a case of a primary signet ring cell carcinoma (PSRCC) of the small bowel in a patient with long-standing Crohn's disease, describing computed tomography (CT)-enterography (CTE) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT features of this rare tumor. CTE demonstrated submucosal thickening of a long ileal segment with preserved mural stratification. PET/CT examination showed increased 18F-FDG uptake in the affected ileal loop, hypermetabolic abdominal and mediastinal lymphadenopathies, and multiple hypermetabolic bone lesions. Iliac crest osteo-medullary biopsy revealed bone marrow infiltration by "signet ring" cells with intestinal differentiation. Double-balloon enteroscopy was used to obtain biopsies that confirmed the ileal origin of the PSRCC.