Guglielmo Manenti

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.

Small Breast Cancers: In Vivo Percutaneous US-guided Radiofrequency Ablation with Dedicated Cool-Tip Radiofrequency System

PURPOSE To evaluate in vivo the efficacy of a newly developed breast radiofrequency (RF) ablation system in human small invasive breast carcinomas in terms of induction of complete tumor necrosis, reproducibility of ablation lesion size and shape, and cosmetic outcome. MATERIALS AND METHODS This study had institutional review board approval, and written informed consent was obtained. Thirty-four postmenopausal women (mean age, 53 years +/- 5 [standard deviation]; range, 49-62 years) with small (< or = 2 cm) biopsy-proved invasive ductal breast carcinomas were enrolled. RF energy was delivered through a 25-mm 15-gauge monopolar cool-tip needle electrode by using the temperature-controlled mode. Patients were divided into three groups according to their breast pattern as assessed at mammography. The volumetric size and geometry of the coagulation zone, together with ablation time, were determined. Histopathologic data were compared with postprocedural 3.0-T contrast material-enhanced magnetic resonance (MR) images. Cosmesis after RF ablation was assessed. Four weeks after RF ablation, patients underwent definitive surgery. RESULTS All ablation procedures were performed successfully. For 97% of the procedures, nicotinamide adenine dinucleotide in its reduced form-diaphorase staining showed no evidence of viable cells. The mean induced ablation volume, as assessed with histologic analysis, was 12.50 cm(3) +/- 0.8. Tumor ablation volume on the postablation MR images showed good correlation with results of histopathologic analysis (r = 0.823, P < .005). No differences were observed in terms of duration of the procedure or ablation volume with respect to the glandular pattern of the breast (P > .05 for both). The general shape of the induced necrosis was close to a sphere in all cases. Cosmesis was excellent in 28 patients. CONCLUSION A dedicated breast cool-tip RF ablation system can induce complete tumor necrosis and reproducible ablation volumes independently of breast glandular pattern, providing excellent cosmesis. Postablation MR images are a reliable tool in predicting histologic findings.

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.

3-T Diffusion tensor imaging of the optic nerve in subjects with glaucoma: correlation with GDx-VCC, HRT-III and Stratus optical coherence tomography findings

Objectives To correlate diffusion-tensor imaging (DTI) of the optic nerve with morphological indices obtained by scanning laser polarimetry (GDx-VCC); confocal scanning laser ophthalmoscopy (Heidelberg III retinal tomograph; HRT-III) and optical coherence tomography (Stratus OCT). Methods Thirty-six subjects (12 with no eye disease and 24 with perimetrically diagnosed glaucoma) were examined. One eye for each participant was studied with 3-Tesla DTI (with automatic generation of mean diffusivity (MD) and fractional anisotropy (FA) values); GDx-VCC, HRT-III and OCT. Single and multiple regression analyses of all variables studied were performed. Results MD displayed the strongest correlation with linear cup/disc ratio (LCDR) from HTR-III (r=0.662), retinal nerve fibre layer (RNFL) thickness (avThickn) from OCT (r=−0.644), and nerve fibre index (NFI) from GDx (r=0.642); FA was strongly correlated with the LCDR (r=−0.499). In multiple regression analyses, MD correlated with LCDR (p=0.02) when all variables were considered; with avThickn (p<0.01) (analysis of all RNFL parameters); with NFI (p<0.01) (analysis of all GDx parameters); with avThickn (p<0.01) (analysis of OCT parameters); with LCDR (p=0.01) (analysis of HRT-III morphometric parameters) and with linear discriminant function (RB) (p=0.02) (analysis of HRT-III indices). As for FA, it correlated with avThickn (p=0.02) when we analysed the OCT parameters and with RB (p=0.01) (analysis of HRT-III indices). Conclusions DTI parameters of the axonal architecture of the optic nerve show good correlation with morphological features of the optic nerve head and RNFL documented with GDx-VCC, HRT-III and OCT.

Giant high-flow renal arteriovenous fistula treated by percutaneous embolization

We report the case of a giant renal arteriovenous fistula after renal biopsy in a 30-year-old man with hematuria and hypertension. We performed percutaneous endovascular embolization using macrocoils to exclude the fistula. The patient made an uneventful recovery with no further hematuria and progressive reduction of blood pressure. Follow-up by digital subtraction angiography (DSA) at 6 months showed complete occlusion of the fistula with no evidence of renal parenchymal infarction. Although giant renal arteriovenous fistulas are generally treated by nephrectomy, this case shows that embolization is a reasonable alternative to surgery.

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.

Perfusion-CT monitoring of cryo-ablated renal cells tumors

BackgroundNo single and thoroughly validated imaging method in monitoring of cryoablated renal cell carcinoma (RCC) is available. The purpose of our study was to determine the feasibility of dynamic contrast-enhanced perfusion CT (pCT) in evaluating the hemodynamic response of RCC.Methods15 patients (14 male, 1 female; age range, 43-81 years; mean age, 62 years) with cryoablated RCC via a transperitoneal approach, underwent to pCT 6-8 months after cryo-therapy. pCT was performed for 65 seconds after intravenous injection of contrast medium (80 mL, 370 mg iodine per millilitre, 4 mL/sec). Perfusion parameters (Time/Density curve; Blood flow, BF; Blood Volume, BV; Mean Transit Time, MTT; Permeability-Surface Area Product, PS) were sampled in the cryoablated tumor area and in ipsilateral renal cortex using deconvolution-based method. A tumor was considered to be not responsive to treatment by CT evidence of pathological contrast enhancement in the cryoablated area or renal mass persistence compared with the preoperative CT control. Written informed consent was obtained from all participants before the study.ResultsAfter cryotherapy, successfully ablated tumor (n = 13) showed decrease in BV (5,39 +/- 1,28 mL/100 g), BF (69,92 +/- 20,12 mL/100 g/min) and PS (16,66 +/- 5,67 mL/100 g/min) value and increased value of MTT (25,35 +/- 4,3 sec) compared with those of normal renal cortex (BV: 117,86 +/- 31,87 mL/100 g/min; BF: 392,39 +/- 117,32 mL/100 g/min; MTT: 18,02 +/- 3,6 sec; PS: 81,68 +/- 22,75 mL/100 g/min). In one patient, assessment of perfusion parameters was not feasible for breathing artifacts. One tumor showed poor response to treatment by the evidence of nodular contrast enhancement in the region encompassing the original lesion. Two typical enhancement patterns were obtained comparing the Time-Density curves of responsive and not responsive ablated tumors.ConclusionPerfusion CT seems to be a feasible and promising technique in monitoring the effects of cryoablation therapy.

Role of combined DWIBS/3D-CE-T1w whole-body MRI in tumor staging: Comparison with PET-CT

OBJECTIVES To assess the diagnostic performance of whole-body magnetic resonance imaging (WB-MRI) by diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) in malignant tumor detection and the potential diagnostic advantages in generating fused DWIBS/3D-contrast enhanced T1w (3D-CE-T1w) images. METHODS 45 cancer patients underwent 18F-FDG PET-CT and WB-MRI for staging purpose. Fused DWIBS/3D-CE T1w images were generated off-line. 3D-CE-T1w, DWIBS images alone and fused with 3D-CE T1w were compared by two readers groups for detection of primary diseases and local/distant metastases. Diagnostic performance between the three WB-MRI data sets was assessed using receiver operating characteristic (ROC) curve analysis. Imaging exams and histopathological results were used as standard of references. RESULTS Areas under the ROC curves of DWIBS vs. 3D-CE-T1w vs. both sequences in fused fashion were 0.97, 0.978, and 1.00, respectively. The diagnostic performance in tumor detection of fused DWIBS/3D-CE-T1w images were statistically superior to DWIBS (p<0.001) and 3D-CE-T1w (p≤0.002); while the difference between DWIBS and 3D-CE-T1w did not show statistical significance difference. Detection rates of malignancy did not differ between WB-MRI with DWIBS and 18F-FDG PET-CT. CONCLUSION WB-MRI with DWIBS is to be considered as alternative tool to conventional whole-body methods for tumor staging and during follow-up in cancer patients.

Role of interventional radiology in pudendal neuralgia: a description of techniques and review of the literature

PurposeThe authors sought to evaluate indications, technical feasibility and clinical efficacy of computed tomography (CT)-guided pudendal nerve infiltration in patients with chronic anoperineal pain by reviewing the role of the CT technique in their personal experience and in the recent interventional literature.Materials and methodsTwenty-eight women, mean age 50 years, and with a diagnosis of pudendal neuralgia on the basis of clinical and electromyographic criteria were enrolled in the study. CT-guided pudendal nerve injections were performed during three consecutive sessions held 2 weeks apart. In each session, patients received two percutaneous injections: one in the ischial spine, and the other in the pudendal (Alcock’s) canal.ResultsOne patient dropped out of the study after the first session. At clinical assessment, 24h h after treatment, 21/27 patients reported significant pain relief. At follow-up at 3, 6, 9 and 12 months, 24/27 patients reported a≥20% improvement in the Quality of Life (QOL) index. Conclusions. In pudendal nerve entrapment, CT-guided perineural injection in the anatomical sites of nerve impingement is a safe and reproducible treatment with a clinical efficacy of 92% at 12 months.RiassuntoObiettivoValutare le indicazioni, la fattibilità tecnica e l’efficacia clinica della infiltrazione TC guidata del nervo pudendo in pazienti con sindrome ano-perineale nevralgica effettuando una revisione del ruolo della tecnica TC nella letteratura recente in ambito interventistico.Materiali e metodiVentotto donne con età media 50 anni e diagnosi di nevralgia del pudendo effettuata sulla base di criteri clinici ed elettromiografici, sono state incluse nel nostro studio. Le iniezioni del nervo pudendo sono state eseguite sotto guida TC, in 3 sedute intervallate da 2 settimane. In ogni seduta, sono state effettuate due sessioni di trattamento iniettivo percutaneo, la prima iniezione è stata effettuata a livello della spina ischiatica e la seconda a livello del canale di Alcock.RisultatiIn un caso la procedura è stata interrotta dopo la prima sessione, è pertanto tale paziente e stata esclusa dalla successiva valutazione. Nella valutazione a ventiquattrore post-trattamento è stato riferito un miglioramento qualitativo significativo della sintomatologia dolorosa in 21 casi su 27; in 24 su 27 casi è stato riportato un miglioramento ≥20% dell’indice di qualità della vita (QOL index) nel follow-up clinico a 3, 6, 9 e 12 mesi.ConclusioniNella sindrome da intrappolamento del nervo pudendo, l’iniezione perineurale TC guidata delle sedi anatomiche di conflitto nervoso risulta una procedura sicura e ripetibile con una efficacia clinica nel 92% dei pazienti trattati nel follow-up a 12 mesi.