Davide Fior

Quantitative evaluation of CT-perfusion map as indicator of tumor response to transarterial chemoembolization and radiofrequency ablation in HCC patients.

PURPOSE To assess if radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) may influence the evaluation of perfusion parameters obtained with CT-perfusion (CT-p) in HCC treated patients. MATERIALS AND METHODS Thirty-three consecutive cirrhotic patients with biopsy-proven diagnosis of HCC lesions and candidates to TACE or RFA were included. The CT-p study of hepatic parenchyma and of treated lesions was performed about 1 month after treatment on 16 multidetector CT after injection of 50mL of non ionic contrast agent (350mg I/mL) at a flow rate of 6mL/s acquiring 40 dynamic scans. A dedicated perfusion software which generated a quantitative map of arterial and portal perfusion by means of colour scale was employed.The following perfusion parameters were assessed before and after RFA or TACE treatment: hepatic perfusion (HP), arterial perfusion (AP), blood volume (BV), time to peak (TTP), hepatic perfusion index (HPI). RESULTS A complete treatment was obtained in 16 cases and incomplete treatment in the 17 remaining cases. The perfusion data of completely treated lesions were: HP 10.2±6.3; AP 10.4±7; BV 4.05±4.8; TTP 38.9±4.2; HPI 9.9±9.2, whereas in partially treated lesions were: HP 43.2±15.1mL/s/100g; AP 38.7±8.8mL/min; BV 20.7±9.5mL/100mg; TTP 24±3.7s; HPI 61.7±7.5%. In adjacent cirrhotic parenchyma, the parameters of all evaluated patients were: HP 13.2±4; AP 12.3±3.4; BV 11.8±2.8; TTP 43.9±2.9; and HPI 17.1±9.8. A significant difference (P<0.001) was found for all parameters between residual viable tumor tissue (P<0.001) compared to successfully treated lesion due to the presence of residual arterial vascular structure in viable portion of treated HCC. CONCLUSION According to our results, CT-p evaluation is not influenced by TACE or RFA treatments, thus representing a feasible technique that allows a reproducible quantitative evaluation of treatment response in HCC patients.

Low kV settings CT angiography (CTA) with low dose contrast medium volume protocol in the assessment of thoracic and abdominal aorta disease: a feasibility study

OBJECTIVE To assess the diagnostic quality of low dose (100 kV) CT angiography (CTA), by using ultra-low contrast medium volume (30 ml), for thoracic and abdominal aorta evaluation. METHODS 67 patients with thoracic or abdominal vascular disease underwent multidetector CT study using a 256 slice scanner, with low dose radiation protocol (automated tube current modulation, 100 kV) and low contrast medium volume (30 ml; 4 ml s(-1)). Density measurements were performed on ascending, arch, descending thoracic aorta, anonymous branch, abdominal aorta, and renal and common iliac arteries. Radiation dose exposure [dose-length product (DLP)] was calculated. A control group of 35 patients with thoracic or abdominal vascular disease were evaluated with standard CTA protocol (automated tube current modulation, 120 kV; contrast medium, 80 ml). RESULTS In all patients, we correctly visualized and evaluated main branches of the thoracic and abdominal aorta. No difference in density measurements was achieved between low tube voltage protocol (mean attenuation value of thoracic aorta, 304 HU; abdominal, 343 HU; renal arteries, 331 HU) and control group (mean attenuation value of thoracic aorta, 320 HU; abdominal, 339; renal arteries, 303 HU). Radiation dose exposure in low tube voltage protocol was significantly different between thoracic and abdominal low tube voltage studies (490 and 324 DLP, respectively) and the control group (thoracic DLP, 1032; abdomen, DLP 1078). CONCLUSION Low-tube-voltage protocol may provide a diagnostic performance comparable with that of the standard protocol, decreasing radiation dose exposure and contrast material volume amount. ADVANCES IN KNOWLEDGE Low-tube-voltage-setting protocol combined with ultra-low contrast agent volume (30 ml), by using new multidetector-row CT scanners, represents a feasible diagnostic tool to significantly reduce the radiation dose delivered to patients and to preserve renal function, while also maintaining adequate diagnostic quality images in assessment of aorta.

Preoperative Computed Tomography to Predict and Stratify the Risk of Severe Pancreatic Fistula After Pancreatoduodenectomy

Abstract The aim of this article is to assess whether measures of abdominal fat distribution, visceral density, and antropometric parameters obtained from computed tomography (CT) may predict postoperative pancreatic fistula (POPF) occurrence. We analyzed 117 patients who underwent pancreatoduodenectomy (PD) and had a preoperative CT scan as staging in our center. CT images were processed to obtain measures of total fat volume (TFV), visceral fat volume (VFV), density of spleen, and pancreas, and diameter of pancreatic duct. The predictive ability of each parameter was investigated by receiver-operating characteristic (ROC) curves methodology and assessing optimal cutoff thresholds. A stepwise selection method was used to determine the best predictive model. Clinically relevant (grades B and C) POPF occurred in 24 patients (20.5%). Areas under ROC-curves showed that none of the parameters was per se significantly predictive. The multivariate analysis revealed that a VFV >2334 cm3, TFV >4408 cm3, pancreas/spleen density ratio <0.707, and pancreatic duct diameter <5 mm were predictive of POPF. The risk of POPF progressively increased with the number of factors involved and age. It is possible to deduce objective information on the risk of POPF from a simple and routine preoperative radiologic workup.

Combined value of apparent diffusion coefficient-standardized uptake value max in evaluation of post-treated locally advanced rectal cancer

AIM To assess the clinical diagnostic value of functional imaging, combining quantitative parameters of apparent diffusion coefficient (ADC) and standardized uptake value (SUV)max, before and after chemo-radiation therapy, in prediction of tumor response of patients with rectal cancer, related to tumor regression grade at histology. METHODS A total of 31 patients with biopsy proven diagnosis of rectal carcinoma were enrolled in our study. All patients underwent a whole body (18)FDG positron emission tomography (PET)/computed tomography (CT) scan and a pelvic magnetic resonance (MR) examination including diffusion weighted (DW) imaging for staging (PET1, RM1) and after completion (6.6 wk) of neoadjuvant treatment (PET2, RM2). Subsequently all patients underwent total mesorectal excision and the histological results were compared with imaging findings. The MR scanning, performed on 1.5 T magnet (Philips, Achieva), included T2-weighted multiplanar imaging and in addition DW images with b-value of 0 and 1000 mm²/s. On PET/CT the SUVmax of the rectal lesion were calculated in PET1 and PET2. The percentage decrease of SUVmax (ΔSUV) and ADC (ΔADC) values from baseline to presurgical scan were assessed and correlated with pathologic response classified as tumor regression grade (Mandards criteria; TRG1 = complete regression, TRG5 = no regression). RESULTS After completion of therapy, all the patients were submitted to surgery. According to the Mandards criteria, 22 tumors showed complete (TRG1) or subtotal regression (TRG2) and were classified as responders; 9 tumors were classified as non responders (TRG3, 4 and 5). Considering all patients the mean values of SUVmax in PET 1 was higher than the mean value of SUVmax in PET 2 (P < 0.001), whereas the mean ADC values was lower in RM1 than RM2 (P < 0.001), with a ΔSUV and ΔADC respectively of 60.2% and 66.8%. The best predictors for TRG response were SUV2 (threshold of 4.4) and ADC2 (1.29 × 10(-3) mm(2)/s) with high sensitivity and specificity. Combining in a single analysis both the obtained median value, the positive predictive value, in predicting the different group category response in related to TRG system, presented R(2) of 0.95. CONCLUSION The functional imaging combining ADC and SUVmax in a single analysis permits to detect changes in cellular tissue structures useful for the assessment of tumour response after the neoadjuvant therapy in rectal cancer, increasing the sensitivity in correct depiction of treatment response than either method alone.

Tumour-related neoangiogenesis: Functional dynamic perfusion computed tomography for diagnosis and treatment efficacy assessment in hepatocellular carcinoma

BACKGROUND Aim of the study was to determine the value of perfusion computed tomography in the quantitative assessment of tumour-related neoangiogenesis for the diagnosis and treatment of hepatocellular carcinoma lesions. METHODS Overall, 47 consecutive patients with cirrhotic liver disease, with a high risk of hepatocellular carcinoma, and undergoing standard surveillance (six-month intervals) were eligible for inclusion in this prospective study; based on Barcelona Clinic Liver Cancer guidelines, 27 patients were enrolled. Perfusion computed tomography was performed in 29 biopsy-proven hepatocellular carcinoma lesions before and after treatment with transarterial chemoembolization or radiofrequency ablation. The dynamic study was performed with a 256-slice multidetector-computed tomography scanner; the following parameters were measured: hepatic perfusion, arterial perfusion, blood volume, hepatic perfusion index, and time-to-peak in all patients. RESULTS Hepatocellular carcinoma lesions had the following median perfusion values: perfusion 46.3mL/min/100g; blood volume 20.4mL/100mg; arterial perfusion 42.9mL/min; hepatic perfusion index 92.5%; time to peak 18.7s. Significantly lower perfusion values were obtained in correctly treated lesions or surrounding parenchyma than in viable hepatocellular carcinoma tissue. CONCLUSIONS In hepatocellular carcinoma, perfusion computed tomography could contribute to a non-invasive quantification of tumour blood supply related to the formation of new arterial structures, and enable the assessment of therapeutic response.

Rectal cancer staging: Multidetector-row computed tomography diagnostic accuracy in assessment of mesorectal fascia invasion

AIM To assess the diagnostic accuracy of multidetector-row computed tomography (MDCT) as compared with conventional magnetic resonance imaging (MRI), in identifying mesorectal fascia (MRF) invasion in rectal cancer patients. METHODS Ninety-one patients with biopsy proven rectal adenocarcinoma referred for thoracic and abdominal CT staging were enrolled in this study. The contrast-enhanced MDCT scans were performed on a 256 row scanner (ICT, Philips) with the following acquisition parameters: tube voltage 120 KV, tube current 150-300 mAs. Imaging data were reviewed as axial and as multiplanar reconstructions (MPRs) images along the rectal tumor axis. MRI study, performed on 1.5 T with dedicated phased array multicoil, included multiplanar T2 and axial T1 sequences and diffusion weighted images (DWI). Axial and MPR CT images independently were compared to MRI and MRF involvement was determined. Diagnostic accuracy of both modalities was compared and statistically analyzed. RESULTS According to MRI, the MRF was involved in 51 patients and not involved in 40 patients. DWI allowed to recognize the tumor as a focal mass with high signal intensity on high b-value images, compared with the signal of the normal adjacent rectal wall or with the lower tissue signal intensity background. The number of patients correctly staged by the native axial CT images was 71 out of 91 (41 with involved MRF; 30 with not involved MRF), while by using the MPR 80 patients were correctly staged (45 with involved MRF; 35 with not involved MRF). Local tumor staging suggested by MDCT agreed with those of MRI, obtaining for CT axial images sensitivity and specificity of 80.4% and 75%, positive predictive value (PPV) 80.4%, negative predictive value (NPV) 75% and accuracy 78%; while performing MPR the sensitivity and specificity increased to 88% and 87.5%, PPV was 90%, NPV 85.36% and accuracy 88%. MPR images showed higher diagnostic accuracy, in terms of MRF involvement, than native axial images, as compared to the reference magnetic resonance images. The difference in accuracy was statistically significant (P = 0.02). CONCLUSION New generation CT scanner, using high resolution MPR images, represents a reliable diagnostic tool in assessment of loco-regional and whole body staging of advanced rectal cancer, especially in patients with MRI contraindications.

Diagnostic Value of Semiquantitative Analysis of Dynamic Susceptibility Contrast Magnetic Resonance Imaging with GD-EOB-DTPA in Focal Liver Lesions Characterization: A Feasibility Study

Purpose. To assess the diagnostic accuracy of dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSCE-MRI) in differentiation between benign and malignant liver lesions by assessment of tumoral perfusion parameters. Methods Materials. Seventy-three patients with known focal liver lesions, including 45 benign (16 FNH, 27 angiomas, and 2 abscesses) and 28 malignant ones (17 metastases, 9 HCCs, and 2 cholangiocarcinoma) underwent 1.5 T MRI upper abdominal study, with standard protocol that included dynamic contrast-enhanced sequences. On dedicated workstation, time-intensity curves were determined and the following perfusion parameters were calculated: relative arterial, venous and late enhancement (RAE, RVE, RLE), maximum enhancement (ME), relative enhancement (RE), and time to peak (TTP). Results. All diagnoses were established either by histopathology or imaging follow-up. Perfusion mean values calculated in benign lesions were RAE 33.8%, RVE 66.03%, RLE 80.63%, ME 776.00%, MRE 86.27%, and TTP 146.95 sec. Corresponding perfusion values calculated in malignant lesions were RAE 22.47%, RVE 40.54%, RLE 47.52%, ME 448.78%, MRE 49.85%, and TTP 183.79 sec. Statistical difference (p < 0.05) was achieved in all the perfusion parameters calculated, obtaining different cluster of perfusion kinetics between benign and malignant lesions. Conclusions. DSCE-MRI depicts kinetic differences in perfusion parameters among the different common liver lesions, related to tumour supply and microvascular characteristics.

Diagnostic value of iterative reconstruction algorithm in low kV CT angiography (CTA) with low contrast medium volume for transcatheter aortic valve implantation (TAVI) planning: image quality and radiation dose exposure

OBJECTIVE: To evaluate image quality and radiation dose exposure of low-kV (100 kV) and low contrast medium (CM) volume CT angiography (CTA) in patients candidate to Transcatheter Aortic Valve Implantation (TAVI), in comparison with standard CTA protocol. METHODS: 79 patients candidate for TAVI were prospectively enrolled in this study and examined with 256-MDCT. 42 patients were evaluated using study-group protocol (100 kV; whole-body retrospective ECG-gating; with 50 ml of CM; iterative reconstruction algorithm) while 37 patients underwent a standard CTA study (120 kV; ECG-gating for chest; 100 ml of CM; FBP reconstruction). Overall image quality was evaluated using a 4-point scale. Vascular enhancement (HU) was then assessed in each patient by manually drawing multiple ROIs in lumen of 7 segments of the whole aorta. The radiation dose exposure of both groups was calculated and all data were compared and statistically analyzed. RESULTS: On low-kV protocol, higher mean attenuation values were achieved in all the measurements as compared to standard protocol. There were no significant differences in the image quality evaluation in both groups. Mean radiation dose value of study group was significantly lower than in control group (reduction of 20%). CONCLUSION: Low kV and low CM volume CTA protocols allow TAVI planning to be carried out with high quality images and a significant reduction in the radiation dose as compared to the standard CTA protocol. ADVANCES IN KNOWLEDGE: Low-kV CTA for pre-operative assessment of patients candidates for TAVI, permits to achieve a significant reduction of radiation dose exposure and contrast medium volume, reducing the risk of contrast induced nephropathy.

Low-dose computed tomography with 4th-generation iterative reconstruction algorithm in assessment of oncologic patients

AIM To compare radiation dose and image quality of low-dose computed tomography (CT) protocol combined with hybrid-iterative reconstruction algorithm with standard-dose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standard-dose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated mA modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 mAs (depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise (SD), sharpness and diagnostic quality with 4-point scale. RESULTS Density values in liver, spleen and aorta were higher in low-dose images (liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen (liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index (CTDIvol) and Dose-Length-Product (DLP) were significantly lower in low-dose CT as compared to standard-dose (DLP 1025.6 mGy*cm vs 1429.2 mGy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality. CONCLUSION Automatic tube-current modulation combined with hybrid-iterative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.