Stefano Mancino

Malignant renal neoplasms: correlation between ADC values and cellularity in diffusion weighted magnetic resonance imaging at 3 T

PurposeThis study aimed at exploring the feasibility of high-field diffusion-weighted magnetic resonance imaging (DW-MRI) (3 T) and to correlate apparent diffusion coefficient (ADC) values with tumour cellularity in renal malignancies.Materials and methodsThirty-seven patients (ten healthy volunteers and 27 patients with suspected renal malignancy) underwent T1-, T2-weighted and T1-weighted contrast-enhanced magnetic resonance imaging (MRI). Diffusion-weighted images were obtained with a single-shot spin-echo echo-planar imaging (SE-EPI) sequence with a b value of 500 s/mm2. All lesions were surgically resected, and mean tumour cellularity was calculated. Comparison between tumour cellularity and mean ADC value was performed using simple linear regression analysis.ResultsThe mean ADC value in normal renal parenchyma was 2.35±0.31×10−3 mm2/s, whereas mean ADC value in renal malignancies was 1.72±0.21×10−3 mm2/s. In our population, there were no statistically significant differences between ADC values of different histological types. The analysis of mean ADC values showed an inverse linear correlation with cellularity in renal malignancies (r=−0.73, p<0.01).ConclusionsDW-MRI is able to differentiate between normal and neoplastic renal parenchyma on the basis of tissue cellularity.RiassuntoObiettivoValutare l’utilità dell’imaging RM ad alto campo (3T) con sequenze pesate in diffusione (DWI) nello studio delle neoplasie renali e correlare i valori del coefficiente apparente di diffusione (ADC) con la cellularità delle neoplasie.Materiali e metodiTrentasette pazienti (10 volontari sani e 27 con lesioni renali sospette) sono stati studiati con imaging RM e sequenze T1, T2 pesate e T1 pesate dopo somministrazione di bolo di contrasto paramagnetico. Le immagini pesate in diffusione (DWI) sono state acquisite con sequenza sSH SE-EPI e fattore b di 500 s/mm2. Per ogni lesione chirurgicamente asportata è stata valutata la cellularità media. L’analisi di regressione lineare semplice è stata utilizzata per valutare la correlazione fra cellularità tumorale e valore ADC.RisultatiL’ADC medio nel parenchima dei pazienti sani è stato 2,35±0,31×10−3 mm2/s. Il valore medio nei tumori renali maligni era di 1,72±0,21×10−3 mm2/s. Non è stata riscontrata una differenza statisticamente significativa tra i valori medi di ADC dei differenti istotipi neoplastici. È stata documentata una correlazione inversa fra il valore medio di ADC e la cellularità media nei tumori renali maligni (r=−0,73, p<0,01).ConclusioniL’imaging in diffusione consente una distinzione significativa tra parenchima renale normale e neoplastico. È possibile differenziare i tessuti neoplastici sulla base della cellularità.

Diffusion tensor magnetic resonance imaging of prostate cancer

Purpose:To explore the feasibility of 3T magnetic resonance (MR) diffusion tensor imaging (DTI) and fiber tracking (FT) in patients with prostate cancer. Materials and methods:Thirty consecutive patients (mean age, 62.5 years) with biopsy proven prostate cancer underwent 3T-MR imaging (MRI) and DTI using a 6-channel external phased-array coil before radical prostatectomy. Regions of interest of 14 pixels were defined in tumors and nonaffected areas in the peripheral zone (PZ) and central gland (CG), according to histopatology after radical prostatectomy. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were determined. Differences in mean ADC and FA values among prostate cancer, normal PZ and CG were compared by 2-sided Student t test. The predominant diffusion direction of the prostate anisotropy was color coded on a directionally encoded color (DEC) map. A 3D reconstruction of fiber tract orientations of the whole prostate was determined using the continuous tracking method. The overall image quality for tumor localization and local staging was assessed in retrospective matching with whole-mount section histopathology images. Nodules detected at MRI were classified as matched lesions if tumor presence and extension were evidenced at histopathology. Results:For all the patients, the DTI sequence images were suitable for the evaluation of the zonal anatomy of the prostate gland and the tumor localization. Quantitative evaluation of the regions of interest (ROIs) showed a mean ADC value significantly lower in the peripheral neoplastic area (1.06 ± 0.37 × 10−3 mm2/s) than in the normal peripheral portion (1.95 ± 0.38 × 10−3 mm2/s) (P < 0.05). The mean FA values calculated in the normal peripheral (0.47 ± 0.04) and central area (0.41 ± 0.08) were very similar (P > 0.05). The mean FA values in the neoplastic lesion (0.27 ± 0.05) were significantly lower (P < 0.05) than in the normal peripheral area and in the normal central and adenomyomatous area. DEC map showed a top-bottom type preferential direction in the peripheral but not in the central area, with the tumor lesions reducing the diffusion coding direction represented as color zones tending toward gray. Tractographic analysis permitted good delineation of the prostate anatomy (capsule outline, peripheral and central area borders) and neoplastic lesion extension and capsule infiltration compared with histopathology. Conclusions:Three Tesla DTI of the prostate gland is feasible and has the potential for providing improved diagnostic information.

In vivo measurement of the apparent diffusion coefficient in normal and malignant prostatic tissue using thin-slice echo-planar imaging.

Purpose.Diffusion is a physical process based on the random movement of water molecules, known as Brownian movement. Diffusion-weighted imaging (DWI) is a magnetic resonance imaging (MRI) technique that provides information on such biophysical properties of tissues as density, cell organisation and microstructure, which influence the diffusion of water molecules. The aim of this study was to evaluate the ability of MRI to obtain information on the diffusion of water molecules in normal and malignant prostate tissues.Materials and methods.Ten volunteers and 19 patients with prostate lesions diagnosed by transrectal ultrasound (TRUS) were enrolled in our study. Morphological imaging was obtained with T2-weighted turbo spin-echo (TSE) sequences with and without fat suppression [spectral presaturation with inversion recovery (SPIR)] and an axial dynamic T1-weighted SPIR fast-field echo (FFE) sequence during intravenous administration of contrast material. DWI was obtained with a high-spatial-resolution singleshot spin-echo echo planar imaging (EPI) inversion recovery (IR) sequence. The apparent diffusion coefficient (ADC) maps were analysed by positioning an 8-pixel region of interest (ROI) over different zones of the prostate, and the focal lesion when present. The tumour was confirmed by a TRUS-guided needle biopsy taken within 1 month of the MRI examination.Results.The mean ADC value of the central zones (1,512.07±124.85×10-3 mm2/s) was significantly lower than the mean ADC of the peripheral zones (1,984.11±226.23×10-3 mm2/s) (p<0.01). The mean ADC value of tumours (958.97±168.98×10-3 mm2/s) was significantly lower than the mean values of normal peripheral zones (p<0.01).Conclusions.Our preliminary results indicate that DWI is useful for characterising tissue in the different regions of the prostate gland and in distinguishing normal from cancerous tissues, given its ability to detect early changes in the structural organisation of prostate tissue.

High-resolution multicontrast-weighted MR imaging from human carotid endarterectomy specimens to assess carotid plaque components

The American Heart Association modified classification for atherosclerotic plaque lesions has defined vulnerable plaques as those prone to rupture. The aim of our study was to assess the sensitivity and specificity of 1.5-T magnetic resonance imaging (MRI) in the evaluation of the characteristics of plaque components. Twelve carotid endarterectomy specimens were imaged by ex-vivo high-resolution 1.5-T MRI. Thirty-four cross-section axial images were selected for pixel-by-pixel basis analysis to demonstrate the most significant tissue features. Data were then submitted for histopathological examination and each specimen analysed in the light of the histological components (lipid core, fibrous tissue, fibrous/loose connective tissue, calcifications). The overall sensitivity and specificity rates for each tissue type were, respectively, 92% and 74% for the lipid core, 82% and 94% for the fibrous tissue, 72% and 87% for the fibrous/loose connective tissue, and 98% and 99% for calcification. The use of 1.5-T MRI appears to be a reliable tool to characterise plaque components and could help in the screening of patients with high risk of plaque rupture. The possibility of applying MRI in clinical daily practice may change the non-invasive approach to carotid artery diagnostic imaging, thus allowing an early identification of patients with vulnerable plaques.

Combined morphological, [1H]-MR spectroscopic and contrast-enhanced imaging of human prostate cancer with a 3-Tesla scanner: preliminary experience

PurposeThe objective of this study was to explore the feasibility of combined morphological magnetic resonance imaging (MRI), [1H]magnetic resonance spectroscopic imaging (MRSI) and quantitative dynamic contrast-enhanced MRI (DCE-MRI) of human prostate cancer at 3 Tesla using a pelvic phased-array coil.Materials and methodsMRI, MRSI and DCE-MRI with a 3-Tesla whole-body scanner were performed in 30 patients with biopsy-proven prostate cancer before radical prostatectomy. High-resolution T2-weighted turbo spin echo (TSE) images were evaluated for visualisation of the peripheral zone, central gland, visibility of the cancer lesion, prostatic capsule delineation and overall image quality according to a five-point scale. Relative levels of the prostate metabolites citrate, choline and creatine were determined in cancer and in the normal peripheral zone (PZ) and central gland (CG). Spectra were also evaluated for the separation of the signal of citrate, choline and creatine and suppression of lipid and water signals. Time-intensity curves were obtained for prostatic cancer and healthy PZ and CG from DCE-MRI. Finally, time of arrival, time to peak, maximum enhancement and wash-in rate in cancer, normal PZ and CG were calculated.ResultsThe high signal-to-noise ratio (SNR) at 3 Tesla provided T2-weighted TSE images with excellent anatomical detail (in-plane voxel size of 0.22×0.22 mm) and good T2 contrast. The increased spectral resolution was sufficient to separate the choline and creatine resonances and allow delineation of the four peaks of citrate resonance. The (choline + creatine)/citrate ratio was elevated in cancer in comparison with PZ and CG (p<0.001). Dynamic contrast-enhanced images showed good temporal resolution. All parameters obtained from DCE-MRI showed a statistically significant (P<0.05) difference between cancer tissue and normal PZ and CG. Wash-in rate and (choline+creatine)/citrate ratio were significantly correlated (r=0.713, P=0.001) in PZ cancer, whereas the correlation was not significant (r=0.617, P=0.06) in CG and in PZ (r=0.530, P=0.08).ConclusionsIt is possible to perform MRI of prostate cancer at 3 Tesla using a pelvic phased-array coil with high spatial, temporal and spectral resolution. The combination of vascular information from DCE-MRI and metabolic data from MRSI has excellent potential for improved accuracy in delineating and staging prostate carcinoma. These results suggest that high magnetic field strengths offer the possibility of studying prostate cancer without use of an endorectal coil.RiassuntoObiettivoEsplorare la possibilità di effettuare uno studio combinato di risonanza magnetica del cancro prostatico di tipo morfologico (MRI), spettroscopico dell’idrogeno (MRSI) e dinamico postcontrastografico (DCE-MRI) a 3 Tesla utilizzando una bobina pelvica phased-array.Materiali e metodiTrenta pazienti con cancro prostatico dimostrato alla biopsia sono stati sottoposti a MRI, MRSI e DCE-MRI con apparecchiatura a 3 Tesla prima della prostatectomia radicale. Le immagini T2 pesate ad alta risoluzione sono state valutate in base ad una scala di 5 punti per la visualizzazione della zona periferica, della ghiandola centrale, della lesione tumorale, per la delineazione della capsula prostatica e per la qualità complessiva dell’immagine. Sono stati determinati i valori relativi dei metaboliti prostatici citrato, colina e creatina nel cancro, nella zona periferica normale (PZ) e nella ghiandola centrale (CG). Gli spettri sono stati anche valutati per la separazione del segnale del citrato, della colina e della creatina e la soppressione del segnale derivante dall’acqua e dai lipidi. Dai dati del DCE-MRI sono state generate curve intensità-tempo in corrispondenza del cancro, della PZ e della CG. Infine sono stati calcolati per il cancro, la PZ normale e la CG il time of arrival, time to peak, maximum enhancement e il wash in rate.RisultatiL’elevato rapporto segnale-rumore (SNR) a 3 Tesla ha permesso di ottenere immagini TSE T2 pesate con un eccellente dettaglio anatomico (dimensioni in piano del voxel di 0,22×0,22 mm) e buon contrasto T2. L’incrementata risoluzione spettrale è risultata sufficiente a separare la risonanza della colina e della creatina e ha permesso di delineare i 4 picchi della risonanza del citrato. Il rapporto (colina+creatina)/citrato è risultato più elevato nel cancro rispetto a quello individuato nella PZ e nella CG (p<0,001). Le immagini dell’acquisizione dinamica post-contrastografica hanno mostrato una buona risoluzione temporale. Tutti i parametri ottenuti dal DCE-MRI hanno mostrato una differenza statisticamente significativa (p<0,05) tra tessuto neoplastico e PZ normale e CG. Il wash in rate e il rapporto (colina+creatina)/citrato sono risultati significativamente correlati (r=0,713, p=0,001) nel cancro nella zona periferica, mentre la correlazione non è risultata significativa nella CG (r=0,617, p=0,06) e nella PZ (r=0,530, p=0,08).ConclusioniÈ possibile effettuare uno studio di risonanza magnetica del cancro prostatico a 3 Tesla con elevata risoluzione spaziale, temporale e spettrale utilizzando una bobina pelvica phased-array. La combinazione delle informazioni derivanti dal DCE-MRI e dai dati spettroscopici ha eccellenti possibilità di incrementare l’accuratezza nella definizione e stadiazione del cancro prostatico. Questi risultati suggeriscono come campi i magnetici ad elevata intensità offrano la possibilità di studiare il cancro prostatico senza l’uso di una bobina endorettale.

Magnetic resonance imaging of the prostate with spectroscopic imaging using a surface coil. Initial clinical experience

Purpose.The purpose of this study was to evaluate the diagnostic ability of proton magnetic resonance spectroscopic imaging (MRSI) in the detection and localisation of prostate cancer, prospectively compared with histopathologic findings.Materials and methods.Magnetic resonance imaging (MRI) and MRSI were performed on 39 patients with prostate-specific antigen (PSA) levels greater than 4 ng/ml and suspicious findings at trans-rectal ultrasound (TRUS). All patients underwent a TRUS ten-core biopsy within 30 days according to a subdivision of the prostate into octants. All studies were interpreted by a dedicated radiologist who reported the areas of interest as normal, equivocal or suspicious on MRI. At MRSI, cancer was defined as possible if the ratio of choline plus creatine to citrate exceeded mean normal peripheral zone values by two standard deviations (SD) or as definite if that ratio exceeded the normal value by three SD. MRI and MRSI findings were spatially correlated with findings obtained from individual biopsy sites.Results.MRI and MRSI alone had sensitivity, specificity, positive and negative predictive values and diagnostic accuracy in the detection of prostate cancer equal to 85%, 75%; 53%, 89%; 65%, 88%; 77%, 74%; and 69%, 79%, respectively. These values were 70%, 89%, 88%, 74% and 79% when MRI and MRSI were combined. Site-by-site analysis of MRI and MRSI findings and biopsy results yielded no significant correlation.Conclusions.The combination of MRSI and MRI provides a significantly higher specificity in the detection of tumours as compared with MRI alone and can be recommended as a problem-solving modality before biopsy in patients with high PSA levels and suspicious TRUS.

Risonanza Magnetica della prostata con imaging spettroscopico mediante bobina di superficie. Esperienza clinica iniziale.

Purpose.The purpose of this study was to evaluate the diagnostic ability of proton magnetic resonance spectroscopic imaging (MRSI) in the detection and localisation of prostate cancer, prospectively compared with histopathologic findings.Materials and methods.Magnetic resonance imaging (MRI) and MRSI were performed on 39 patients with prostate-specific antigen (PSA) levels greater than 4 ng/ml and suspicious findings at trans-rectal ultrasound (TRUS). All patients underwent a TRUS ten-core biopsy within 30 days according to a subdivision of the prostate into octants. All studies were interpreted by a dedicated radiologist who reported the areas of interest as normal, equivocal or suspicious on MRI. At MRSI, cancer was defined as possible if the ratio of choline plus creatine to citrate exceeded mean normal peripheral zone values by two standard deviations (SD) or as definite if that ratio exceeded the normal value by three SD. MRI and MRSI findings were spatially correlated with findings obtained from individual biopsy sites.Results.MRI and MRSI alone had sensitivity, specificity, positive and negative predictive values and diagnostic accuracy in the detection of prostate cancer equal to 85%, 75%; 53%, 89%; 65%, 88%; 77%, 74%; and 69%, 79%, respectively. These values were 70%, 89%, 88%, 74% and 79% when MRI and MRSI were combined. Site-by-site analysis of MRI and MRSI findings and biopsy results yielded no significant correlation.Conclusions.The combination of MRSI and MRI provides a significantly higher specificity in the detection of tumours as compared with MRI alone and can be recommended as a problem-solving modality before biopsy in patients with high PSA levels and suspicious TRUS.

Magnetic resonance imaging of the prostate with spectroscopic imaging using a surface coil. Initial clinical experience@@@Risonanza magnetica della prostata con imaging spettroscopico mediante bobina di superficie. Esperienza clinica iniziale

Purpose.The purpose of this study was to evaluate the diagnostic ability of proton magnetic resonance spectroscopic imaging (MRSI) in the detection and localisation of prostate cancer, prospectively compared with histopathologic findings.Materials and methods.Magnetic resonance imaging (MRI) and MRSI were performed on 39 patients with prostate-specific antigen (PSA) levels greater than 4 ng/ml and suspicious findings at trans-rectal ultrasound (TRUS). All patients underwent a TRUS ten-core biopsy within 30 days according to a subdivision of the prostate into octants. All studies were interpreted by a dedicated radiologist who reported the areas of interest as normal, equivocal or suspicious on MRI. At MRSI, cancer was defined as possible if the ratio of choline plus creatine to citrate exceeded mean normal peripheral zone values by two standard deviations (SD) or as definite if that ratio exceeded the normal value by three SD. MRI and MRSI findings were spatially correlated with findings obtained from individual biopsy sites.Results.MRI and MRSI alone had sensitivity, specificity, positive and negative predictive values and diagnostic accuracy in the detection of prostate cancer equal to 85%, 75%; 53%, 89%; 65%, 88%; 77%, 74%; and 69%, 79%, respectively. These values were 70%, 89%, 88%, 74% and 79% when MRI and MRSI were combined. Site-by-site analysis of MRI and MRSI findings and biopsy results yielded no significant correlation.Conclusions.The combination of MRSI and MRI provides a significantly higher specificity in the detection of tumours as compared with MRI alone and can be recommended as a problem-solving modality before biopsy in patients with high PSA levels and suspicious TRUS.