Ettore Squillaci

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.

C-arm cone-beam computed tomography in interventional oncology: technical aspects and clinical applications

C-arm cone-beam computed tomography (CBCT) is a new imaging technology integrated in modern angiographic systems. Due to its ability to obtain cross-sectional imaging and the possibility to use dedicated planning and navigation software, it provides an informed platform for interventional oncology procedures. In this paper, we highlight the technical aspects and clinical applications of CBCT imaging and navigation in the most common loco-regional oncological treatments.

Differences between Proximal versus Distal Intraorbital Optic Nerve Diffusion Tensor Magnetic Resonance Imaging Properties in Glaucoma Patients

PURPOSE To analyze in vivo the diffusion tensor magnetic resonance imaging (DT-MRI) properties of the intraorbital optic nerve at two different levels: Proximal to the optic nerve head (ONH) and distal to the ONH at the level of the orbital apex in glaucoma patients. METHODS Twenty-four patients with primary open-angle glaucoma were examined. The categorization into early and severe glaucoma was performed by Hodapps classification. Fifteen healthy individuals served as controls. DT-MRI was performed with a 3T-MR unit. RESULTS At early stage mean diffusivity (MD) values were higher at the proximal site with respect to the distal site. On the contrary, a decrease in fractional anisotropy (FA) was observed only relative to patient stage, independent of optic nerve site. Moreover, at early disease stage an increase in overall diffusivities, was evident at the proximal site, whereas at the distal site a decrease of the largest diffusivity and an increase in both the intermediate and smallest diffusivities were observed. FA and MD measured at the proximal site, had, respectively, the highest sensitivity and specificity in discriminating between healthy and glaucomatous eyes. CONCLUSIONS Our study represents the first attempt to evaluate in vivo fiber integrity changes along the optic nerve with DT-MRI. Optic nerve degeneration appears to be a process that affects differently the proximal and the distal segments of the optic nerve. The complementary high sensitivity of FA with the high specificity of MD at the proximal site may provide reliable indexes for the identification of glaucomatous patients at early stages.

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.

Palliative treatment of neoplastic strictures by self-expanding nitinol Strecker stent

The purpose of this study was to evaluate technical and clinical results of self-expanding esophageal stent implanted in patients with malignant esophageal strictures and clinically significant dysphagia. From June 1992 to September 1994, 27 patients with inoperable tumors of the esophagus or gastric cardiac were treated by placement of 37 self-expanding nitinol stents. Water-soluble contrast and endoscopy studies were performed after the procedure and during the follow-up period. Successful stenting of the stricture was achieved in 27 patients. The mean dysphagia grade dropped from 2.3 to 1 (SD ± 0.54) immediately after the procedure. After the insertion of the stent, 16 patients died in a period of time ranging from 0 to 13 months (mean 5.6 months), whereas at the end of the study 11 patients were alive 4–15 months after the procedure (mean 8.3 months). No major complications were observed. The results of this study are encouraging because esophageal stent placement was technically easy and clinically effective.

The role of computed tomography in the preoperative assessment of gastrointestinal causes of acute abdomen in elderly patients

Gastro-intestinal disorders in older patients is a medical emergency that requires immediate medical care. Chances of recovery improve with an early diagnosis and treatment. It might be caused by a number of different diseases, including perforations by foreign bodies, colon cancer, diverticulitis, ischemia. CT is often the initial modality used to assess patients with acute abdomen, the radiologist may be the first to suggest such a diagnosis. Computed tomography allows to identify the site of gastrointestinal perforations, of ischemia and to determine the most predictive signs in this diagnosis. The purpose of this study was to assess the diagnostic performance of CT gastrointestinal emergency of elderly patients with nontraumatic acute abdominal pain. The cases of 126 consecutively registered patients 65 years old or older presenting to the emergency department with acute abdominal pain and who underwent CT were retrospectively reviewed by two radiologists. Diagnostic accuracy was calculated according to the level of correctly classified cases in both the entire cohort and a surgical subgroup and was compared between readings. Agreement between each reading and the reference diagnosis and interobserver agreement were assessed with kappa statistics. In both the entire cohort (87.5% vs 85.3%, p = 0.07) and the surgical group (94% vs 91%, p = 0.15), there was no significant difference in CT accuracy between diagnoses made by the radiologist. Agreement between the CT diagnosis and the final diagnosis was excellent. In the care of elderly patients, CT is accurate for diagnosing the cause of acute abdominal pain, particularly when it is of gastrointestinal surgical origin. Thus CT interpretation should not be delayed until complete clinicobiologic data are available, and the images should be quickly transmitted to the emergency physician so that appropriate therapy can be begun.