StepBrain: A 3-Dimensionally Printed Multicompartmental Anthropomorphic Brain Phantom to Simulate PET Activity Distributions.

An innovative multicompartmental anatomic brain phantom (StepBrain) is described to simulate the in vivo tracer uptake of gray matter, white matter, and striatum, overcoming the limitations of currently available phantoms. Methods: StepBrain was created by exploiting the potential of fused deposition modeling 3-dimensional printing to replicate the real anatomy of the brain compartments, as modeled through ad hoc processing of healthy-volunteer MR images. Results: A realistic simulation of 18F-FDG PET brain studies, using target activity to obtain the real concentration ratios, was obtained, and the results of postprocessing with partial-volume effect correction tools developed for human PET studies confirmed the accuracy of these methods in recovering the target activity concentrations. Conclusion: StepBrain compartments (gray matter, white matter, and striatum) can be simultaneously filled, achieving different concentration ratios and allowing the simulation of different (e.g., amyloid, tau, or 6-fluoro-l-dopa) tracer distributions, with a potentially valuable role for multicenter PET harmonization studies.

Heart rate estimation from ballistocardiogram signals processing via low-cost telemedicine architectures: a comparative performance evaluation.

Medical devices (MDs) have been designed for monitoring the parameters of patients in many sectors. Nonetheless, despite being high-performing and reliable, they often turn out to be expensive and intrusive. In addition, MDs are almost exclusively used in controlled, hospital-based environments. Paving a path of technological innovation in the clinical field, a very active line of research is currently dealing with the possibility to rely on non-medical-graded low-cost devices, to develop unattended telemedicine (TM) solutions aimed at non-invasively gathering data, signals, and images. In this article, a TM solution is proposed for monitoring the heart rate (HR) of patients during sleep. A remote patient monitoring system (RPMS) featuring a smart belt equipped with pressure sensors for ballistocardiogram (BCG) signals sampling was deployed. A field trial was then conducted over a 2-month period on 24 volunteers, who also agreed to wear a finger pulse oximeter capable of producing a photoplethysmography (PPG) signal as the gold standard, to examine the feasibility of the solution via the estimation of HR values from the collected BCG signals. For this purpose, two of the highest-performing approaches for HR estimation from BCG signals, one algorithmic and the other based on a convolutional neural network (CNN), were retrieved from the literature and updated for a TM-related use case. Finally, HR estimation performances were assessed in terms of patient-wise mean absolute error (MAE). Results retrieved from the literature (controlled environment) outperformed those achieved in the experimentation (TM environment) by 29% (MAE = 4.24 vs. 5.46, algorithmic approach) and 52% (MAE = 2.32 vs. 3.54, CNN-based approach), respectively. Nonetheless, a low packet loss ratio, restrained elaboration time of the collected biomedical big data, low-cost deployment, and positive feedback from the users, demonstrate the robustness, reliability, and applicability of the proposed TM solution. In light of this, further steps will be planned to fulfill new targets, such as evaluation of respiratory rate (RR), and pattern assessment of the movement of the participants overnight.

A rare case of congenital aneurysm of the portal system at level of spleno-porto-mesenteric confluence complicated by massive thrombosis.

Portal venous aneurysm is a rare and potential dangerous vascular pathology, which can result in thrombosis or rupture. It may be congenital or acquired. Acquired form can be related mainly to portal hypertension, chronic hepatic disease, and trauma. We present a peculiar case of a congenital aneurysm involving the hepatic portal system in nearly all its extra-hepatic components: the main portal trunk, the spleno-porto-mesenteric confluence and the distal segment of splenic, superior, and inferior mesenteric veins, in a 20-year-old male patient. The aneurysm was complicated by massive thrombosis in absence of further predisposing factors.

Precocious ischemia preceding bilateral adrenal hemorrhage: A case report.

We present a case of a middle-age male who presented in emergency room with nonspecific abdominal pain. A contrast-enhanced computer tomography (ceCT) scan showed a reduced perfusion of both adrenal glands. The clinical examinations and the laboratory tests were negative for an adrenal pathological process. To reassess the adrenal ischemia, a second ceCT scan was performed 5 days later showing an acute bilateral adrenal hemorrhage. These findings demonstrated that the previous adrenal hypoperfusion represented the prodromal manifestation of a hemorrhagic intraglandular process. This case suggests that adrenal hypoperfusion detected on tomographic imaging dictates a prompt clinical management finalized to strictly monitor the potential evolution towards a more aggressive pathological condition and confirms the pivotal role of imaging in the diagnosis of such uncommon disorder.

A low-cost open-architecture taste delivery system for gustatory fMRI and BCI experiments.

BACKGROUND: Tasting is a complex process involving chemosensory perception and cognitive evaluation. Different experimental designs and solution delivery approaches may in part explain the variability reported in literature. These technical aspects certainly limit the development of taste-related brain computer interface devices. NEW METHOD: We propose a novel modular, scalable and low-cost device for rapid injection of small volumes of taste solutions during fMRI experiments that gathers the possibility to flexibly increase the number of channels, allowing complex multi-dimensional taste experiments. We provide the full description of the hardware and software architecture and illustrate the application of the working prototype in single-subject event-related fMRI experiments by showing the BOLD responses to basic taste qualities and to five intensities of tastes during the course of perception. RESULTS: The device is shown to be effective in activating multiple clusters within the gustatory pathway and a precise time-resolved event-related analysis is shown to be possible by the impulsive nature of the induced perception. COMPARISON WITH EXISTING METHOD(S): This gustometer represents the first implementation of a low-cost, easily replicable and portable device that is suitable for all kinds of fMRI taste experiments. Its scalability will boost the experimental design of more complex multi-dimensional fMRI studies of the human taste pathway. CONCLUSIONS: The gustometer represents a valid open-architecture alternative to other available devices and its spread and development may contribute to an increased standardization of experimental designs in human fMRI studies of taste perception and pave the way to the development of novel taste-related BCIs.

Cortical representation of different taste modalities on the gustatory cortex: A pilot study.

BACKGROUND: Right insular cortex is involved in taste discrimination, but its functional organization is still poorly known. In general, sensory cortices represent the spatial prevalence of relevant features for each sensory modality (visual, auditory, somatosensory) in an ordered way across the cortical space. Following this analogy, we hypothesized that primary taste cortex is organized in similar ordered way in response to six tastes with known receptorial mechanisms (sweet, bitter, sour, salt, umami, CO2). DESIGN: Ten normal subjects were enrolled in a pilot study. We used functional magnetic resonance imaging (fMRI), a high resolution cortical registration method, and specialized procedures of feature prevalence localization, to map fMRI responses within the right insular cortex, to water solutions of quinine hydrochloride (bitter), Acesulfamate K (sweet), sodium chloride (salt), mono potassium glutamate + inosine 5' mono phosphate (Umami), citric acid (sour) and carbonated water (CO2). During an fMRI scan delivery of the solutions was applied in pseudo-random order interleaved with cleaning water. RESULTS: Two subjects were discarded due to excessive head movements. In the remaining subjects, statistically significant activations were detected in the fMRI responses to all tastes in the right insular cortex (p<0.05, family-wise corrected for multiple comparisons). Cortical representation of taste prevalence highlighted two spatially segregated clusters, processing two and three tastes coupled together (sweet-bitter and salt-umami-sour), with CO2 in between. CONCLUSIONS: Cortical representation of taste prevalence within the right primary taste cortex appears to follow the ecological purpose of enhancing the discrimination between safe nutrients and harmful substances.

Prognostic value of atherosclerotic burden and coronary vascular function in patients with suspected coronary artery disease.

PURPOSE: To evaluate the prognostic value of coronary atherosclerotic burden, assessed by coronary artery calcium (CAC) score, and coronary vascular function, assessed by coronary flow reserve (CFR) in patients with suspected coronary artery disease (CAD). METHODS: We studied 436 patients undergoing hybrid 82Rb positron emission tomography/computed tomography imaging. CAC score was measured according to the Agatston method, and patients were categorized into three groups (0, <400, and ≥400). CFR was calculated as the ratio of hyperemic to baseline myocardial blood flow, and it was considered reduced when <2. RESULTS: Follow-up was 94% complete during a mean period of 47±15 months. During follow-up, 17 events occurred (4% cumulative event rate). Event-free survival decreased with worsening of CAC score category (p < 0.001) and in patients with reduced CFR (p < 0.005). At multivariable analysis, CAC score ≥400 (p < 0.01) and CFR (p < 0.005) were independent predictors of events. Including CFR in the prognostic model, continuous net reclassification improvement was 0.51 (0.14 in patients with events and 0.37 in those without). At classification and regression tree analysis, the initial split was on CAC score. For patients with a CAC score < 400, no further split was performed, while patients with a CAC score ≥400 were further stratified by CFR values. Decision curve analyses indicate that the model including CFR resulted in a higher net benefit across a wide range of decision threshold probabilities. CONCLUSIONS: In patients with suspected CAD, CFR provides significant incremental risk stratification over established cardiac risk factors and CAC score for prediction of adverse cardiac events.

Coronary atherosclerotic burden vs. coronary vascular function in diabetic and nondiabetic patients with normal myocardial perfusion: a propensity score analysis.

PURPOSE: To assess the relationship between coronary atherosclerotic burden and vascular function in diabetic and nondiabetic patients after balancing for coronary risk factors. METHODS: We studied 672 patients without overt coronary artery disease and normal myocardial perfusion on stress 82Rb PET/CT imaging. To account for differences in baseline characteristics between diabetic patients and nondiabetic patients, we created a propensity score-matched cohort considering clinical variables and coronary risk factors. RESULTS: Before matching, diabetic patients had higher coronary artery calcium (CAC) scores (p < 0.001) and lower coronary flow reserve (CFR; p < 0.001) than nondiabetic patients. After matching, CAC scores were comparable between diabetic and nondiabetic patients, but diabetic patients still had lower hyperaemic myocardial blood flow (p < 0.001) and CFR (p < 0.05). Patients were categorized by ln(CAC score) quartiles. There was a decrease in CFR with increasing CAC score quartile in both diabetic patients (p for trend < 0.01) and nondiabetic patients (p for trend < 0.005). Diabetes was associated with lower CFR across quartile categories (p < 0.002). In a multivariable linear regression analysis, CAC score was inversely related to CFR in both diabetic patients (p < 0.05) and nondiabetic patients (p < 0.001). CONCLUSION: Diabetic patients had higher CAC scores than nondiabetic patients, but the difference disappeared when clinical characteristics were taken into account. Of note, diabetic patients also had lower CFR regardless of CAC score than nondiabetic patients after matching. Thus, coronary atherosclerotic burden and vascular function have to be seen as two different entities.

Tomographic imaging of the spleen: the role of morphological and metabolic features in differentiating benign from malignant diseases.

To evaluate the tomographic features in differentiating benign from malignant splenic diseases, 54 patients with a cytohistological examination and a contrast-enhanced multidetector computed tomography (ce-MDCT) and/or positron emission tomography/computed tomography (PET/CT) were retrospectively selected. Significant associations were observed between ce-MDCT Pattern 3 (focal hyperdense lesion) and Pattern 4 (infarcts/cysts) as well as PET/CT Pattern 3 (focal photopenia/diffuse uptake

Colorectal cancer and 18FDG-PET/CT: what about adding the T to the N parameter in loco-regional staging?

AIM: To evaluate whether FDG-positron emission tomography (PET)/computed tomography (CT) may be an accurate technique in the assessment of the T stage in patients with colorectal cancer. METHODS: Thirty four consecutive patients (20 men and 14 women; mean age: 63 years) with a histologically proven diagnosis of colorectal adenocarcinoma and scheduled for surgery in our hospital were enrolled in this study. All patients underwent FDG-PET/CT preoperatively. The primary tumor site and extent were evaluated on PET/CT images. Colorectal wall invasion was analysed according to a modified T classification that considers only three stages (≤ T2, T3, T4). Assessment of accuracy was carried out using 95% confidence intervals for T. RESULTS: Thirty five/37 (94.6%) adenocarcinomas were identified and correctly located on PET/CT images. PET/CT correctly staged the T of 33/35 lesions identified showing an accuracy of 94.3% (95% CI: 87%-100%). All T1, T3 and T4 lesions were correctly staged, while two T2 neoplasms were overstated as T3. CONCLUSION: Our data suggest that FDG-PET/CT may be an accurate modality for identifying primary tumor and defining its local extent in patients with colorectal cancer.

Radiotherapy of large target volumes in Hodgkin's lymphoma: normal tissue sparing capability of forward IMRT versus conventional techniques.

BACKGROUND: This paper analyses normal tissue sparing capability of radiation treatment techniques in Hodgkin's lymphoma with large treatment volume. METHODS: 10 patients with supradiaphragmatic Hodgkin's lymphoma and planning target volume (PTV) larger than 900 cm3 were evaluated. Two plans were simulated for each patient using 6 MV X-rays: a conventional multi-leaf (MLC) parallel-opposed (AP-PA) plan, and the same plan with additional MLC shaped segments (forward planned intensity modulated radiation therapy, FPIMRT). In order to compare plans, dose-volume histograms (DVHs) of PTV, lungs, heart, spinal cord, breast, and thyroid were analyzed. The Inhomogeneity Coefficient (IC), the PTV receiving 95% of the prescription dose (V95), the normal tissue complication probability (NTCP) and dose-volume parameters for the OARs were determined. RESULTS: the PTV coverage was improved (mean V95AP-PA=95.9 and ICAP-PA=0.4 vs. V95FPIMRT=96.8 and ICFPIMRT=0.31, por=30 Gy resulted significantly reduced when using the FPIMRT technique. CONCLUSIONS: The FPIMRT technique can represent a very useful and, at the same time, simple method for improving PTV conformity while saving critical organs when large fields are needed as in Hodgkin's lymphoma.