Lorenzo Nicola Mazzoni

MR-diffusion weighted imaging of healthy liver parenchyma: repeatability and reproducibility of apparent diffusion coefficient measurement.

To compare repeatability and reproducibility of four different methods of apparent diffusion coefficient (ADC) evaluation of liver parenchyma. In fact, repeatability and reproducibility assessment is mandatory in quantitative evaluations, however, these have not been accurately investigated in liver MR‐diffusion‐weighted studies.

Looking at my body. Similarities and differences between anorexia nervosa patients and controls in body image visual processing

BACKGROUND Body image distortion is a core symptom of eating disorders. Functional magnetic resonance imaging (fMRI) studies on body image processing, described different patterns of neural response, mainly involving the inferior and superior parietal lobules, and the dorsolateral prefrontal cortex (DLPFC), with conflicting results. METHODS The neural response to the view of their own body pictures (normal size and distorted) was evaluated in 18 female anorexia nervosa (AN) restricting type patients, and in 19 healthy female subjects (HC) using fMRI. Clinical assessment was performed by means of the structured clinical interview for DSM-IV and self-reported questionnaires. RESULTS In response to the body image distortion, patients and controls showed an inverse pattern of activation, with the widest extent of activation in the oversize condition in AN, while in the undersize condition in HC. AN and HC showed a similar pattern of neural response to the view of their own body, with an increased activation in the extrastriate body area, superior and inferior parietal lobule and prefrontal areas, although the extent of activation in HC was more limited as compared with AN patients. Increased activity in AN patients, compared with HC, was observed in the DLPFC in response to the oversized body picture and a significant correlation was found in AN patients between DLPFC activation and eating disorder psychopathology. CONCLUSIONS Our findings suggest the existence of a continuum from normalcy to pathology in neural response to body image, and confirm the clinical relevance of body image distortion in AN, reinforcing the key role of attentive, executive and self-evaluation networks in AN visual processing of own distorted body image.

Dose exposure in the ITALUNG trial of lung cancer screening with low-dose CT

Few data are available on the effective dose received by participants in lung cancer screening programmes with low-dose CT (LDCT). We report the collective effective dose delivered to 1406 current or former smokers enrolled in the ITALUNG trial who completed 4 annual LDCT examinations and related further investigations including follow-up LDCT, 2-[(18)F]flu-2-deoxy-d-glucose positron emission tomography (FDG-PET) or CT-guided fine needle aspiration biopsy (FNAB). Using the air CT dose index and Monte Carlo simulations on an anthropomorphic phantom, the whole-body effective dose associated with LDCT was determined for the eight CT scanners used in the trial. A value of 7 mSv was assigned to FDG-PET while the measured mean effective dose of CT-guided FNAB was 1.5 mSv. The mean collective effective dose in the 1406 subjects ranged between 8.75 and 9.36 Sv and the mean effective dose to the single subject over 4 years was between 6.2 and 6.8 mSv (range 1.7-21.5 mSv) according to the cranial-caudal length of the LDCT volume. 77.4% of the dose was owing to annual LDCT and 22.6% to further investigations. Considering the nominal risk coefficients for stochastic effects after exposure to low-dose radiation according to the National Radiological Protection Board, International Commission on Radiological Protection (ICRP) 60, ICRP103 and Biological Effects of Ionizing Radiation VII, the mean number of radiation-induced cancers ranged between 0.12 and 0.33 per 1000 subjects. The individual effective dose to participants in a 4-year lung cancer screening programme with annual LDCT is very low and about one-third of the effective dose that is associated with natural background radiation and diagnostic radiology in the same time period.

Impact of cerebrospinal fluid contamination on brain metabolites evaluation with 1H-MR spectroscopy: A single voxel study of the cerebellar vermis in patients with degenerative ataxias

To investigate the impact of cerebrospinal fluid (CSF) contamination on metabolite evaluation in the superior cerebellar vermis with single‐voxel 1H‐MRS in normal subjects and patients with degenerative ataxias.

Quality assurance multicenter comparison of different MR scanners for quantitative diffusion-weighted imaging

To propose a magnetic resonance imaging (MRI) quality assurance procedure that can be used for multicenter comparison of different MR scanners for quantitative diffusion‐weighted imaging (DWI).

Magnetization transfer MR imaging demonstrates degeneration of the subcortical and cortical gray matter in Huntington disease.

BACKGROUND AND PURPOSE: GM is typically affected in HD since the presymptomatic stage. Our aim was to investigate with MT MR imaging the microstructural changes of the residual brain subcortical and cortical GM in carriers of the HD gene and to preliminarily assess their correlation with the clinical features. MATERIALS AND METHODS: Fifteen HD gene carriers with a range of clinical severity and 15 age- and sex-matched healthy controls underwent MT MR imaging on a 1.5T scanner. The MT ratio was measured automatically in several subcortical and cortical GM regions (striatal nuclei; thalami; and the neocortex of the frontal, temporal, parietal, and occipital lobes) by using FLS tools. RESULTS: The MT ratio was significantly (P < .05 with Bonferroni correction for multiple comparison) decreased in all subcortical structures except the putamen and decreased diffusely in the cerebral cortex of HD carriers compared with controls. Close correlation was observed between the subcortical and cortical regional MT ratios and several clinical variables, including disease duration, motor disability, and scores in timed neuropsychological tests. CONCLUSIONS: MT imaging demonstrates degeneration of the subcortical and cortical GM in HD carriers and might serve, along with volumetric assessment, as a surrogate marker in future clinical trials of HD.

Effects of gadoxetic acid on quantitative diffusion-weighted imaging of the liver

To prospectively evaluate the effect of gadoxetic acid (Gd‐EOB‐DTPA; Primovist, Bayer‐Schering, Berlin, Germany) on quantitative diffusion‐weighted imaging (DWI) using the Le Bihan IntraVoxel Incoherent Motion model and considering separately the following parameters: slow diffusion coefficient (D), fast diffusion coefficient (D*), perfusion fraction (PF), and apparent diffusion coefficient (ADC).

Diffusion‐weighted signal models in healthy and cancerous peripheral prostate tissues: Comparison of outcomes obtained at different b‐values

To evaluate the dependence on the b‐values adopted of apparent diffusion coefficient (ADC), perfusion fraction (PF), slow and fast diffusion coefficient (Dslow, Dfast), corrected diffusion coefficient (D) and kurtosis (K), in healthy peripheral (HP) and peripheral cancerous (PCa) prostate tissues.

MR-diffusion imaging in assessing chronic liver diseases: does a clinical role exist?

PurposeThis study was done to evaluate whether and which of the magnetic resonance diffusion-weighted imaging (MR-DWI) parameters — apparent diffusion coefficient (ADC), diffusion (D) or perfusion fraction (f) — correlates with the degree of chronic liver disease progression.Materials and methodsTwenty-eight patients were evaluated with abdominal MR-DWI from March to November 2010: seven healthy volunteers, seven patients with chronic liver disease F0–F2 (METAVIR score), seven F3–F4 Child-Pugh A, and seven F4 Child-Pugh BC, classified as groups 1–4, respectively. DWI acquisitions were performed during breath-holding (b = 0–150 s/mm2 and 1,000) and free breathing (multi-b = 0–200–400–600–800–1,000 s/mm2). Using a double-blind control procedure, two observers estimated ADC, D, and f by applying a region of interest (ROI) in 4/12 sections in the middle-lower portion of the right hepatic lobe. Statistical analysis was done with analysis of variance (ANOVA).ResultsA reduction in the mean value of f, ADC150 and, to a lesser extent, ADC1,000 is shown to progress from healthy volunteers (group 1) to cirrhosis patients (group 4), with wide overlap among groups. There were no statistically significant changes of D.ConclusionsOur results indicate that stratifying patients with chronic liver disease for clinical purposes cannot be done with DWI. However, there is a tendency among groups for reduced perfusion-related parameters as chronic liver disease progresses.RiassuntoObiettivoScopo del nostro lavoro è stato valutare se e quale fra i parametri legati alla diffusione in risonanza magnetica (RM-DwI), coefficiente di diffusione apparente (ADC), diffusione (D), frazione di perfusione (f) correli con l’avanzare del grado dell’epatopatia cronica sclerogena.Materiali e metodiDa marzo a novembre 2010 sono stati valutati con RM 28 soggetti: 7 sani, 7 epatopatici cronici F0–F2 secondo Metavir, 7 F3–F4 Child A e 7 F4 Child B-C, denominati gruppi I–II–III–IV rispettivamente. Sono state eseguite acquisizioni DwI a respiro sospeso (b=0–150 e 1000 s/mm2) e libero (poli-b=0–200–400–600–800–1000 s/mm2). Tramite regione di interesse (ROI) in 4/12 sezioni nella porzione medio-inferiore del lobo epatico destro sono stati stimati in cieco da due osservatori i parametri ADC, D, f con statistica secondo Analysis of Variance Between Groups (ANOVA).RisultatiSi è evidenziata una riduzione del valor medio di f, dell’ADC150 e, in misura minore, dell’ADC1000 al progredire da sano (gruppo I) verso cirrotico (gruppo IV) con ampia sovrapposizione fra i vari gruppi; non è stata invece osservata variazione statisticamente significativa di D.ConclusioniI nostri risultati indicano che tramite DwI non è consentita una stratificazione ad uso clinico dei pazienti epatopatici cronici. Si riscontra tuttavia tendenza per gruppi alla riduzione dei parametri legati alla perfusione al progredire dell’epatopatia sclerogena.

Assessment of liver perfusion by IntraVoxel Incoherent Motion (IVIM) magnetic resonance-diffusion-weighted imaging: Correlation with phase-contrast portal venous flow measurements

Objectives To prospectively verify, in vivo, Le Bihan’s model of signal decay in magnetic resonance/diffusion-weighted imaging (intravoxel incoherent motion) in healthy liver parenchyma. Methods Informed consent and institutional board approval were obtained. To measure both underfasting and postprandial conditions, apparent, slow, and fast diffusion (D*) coefficients and perfusion fraction of liver parenchyma, 40 healthy volunteers (19 women and 21 men) underwent a 3.0-T magnetic resonance imaging examination, including portal venous flow measurements by a 2-dimensional phase-contrast sequence, and multi-b diffusion-weighted imaging acquired before and 30 minutes after a 600-Kcal meal. Parameters were measured by fitting procedure with regions of interest drawn on the right liver lobe. Paired-sample t test was performed to search for any statistically significant difference between preprandial and postprandial values of each parameter and of portal flow. Pearson correlation coefficients were calculated to evaluate the relationship between portal flow increase and diffusion-weighted imaging parameter changes in postprandial conditions. Interobserver agreement for measurement of the intravoxel incoherent motion parameters was determined, both for preprandial and postprandial values. Results Mean increase in postprandial portal flow was 98% (P < 0.0009). The t test did not show any statistically significant difference between the preprandial and postprandial values for apparent, slow diffusion coefficients and perfusion fraction (P ≥ 0.05), whereas a statistically significant postprandial increase (P < 0.01) of D* was detected. Correlation with portal venous flow increase at Pearson test was statistically significant for D* (P = 0.04) and nonsignificant for the other parameters. All the parameters showed wide variability, with a higher percent coefficient of variation for D*. Interobserver agreement was always greater than 0.70. Conclusions This study verifies Le Bihan’s theory, confirming that in the liver, D* is influenced by perfusional changes related to portal venous flow.