Dynamic Contrast-Enhanced MR with Quantitative Perfusion Analysis of Small Bowel in Vascular Assessment between Inflammatory and Fibrotic Lesions in Crohn's Disease: A Feasibility Study.

Aim: To assess the feasibility of dynamic contrast-enhanced perfusion-MRI in characterization of active small-bowel inflammation and chronic mural fibrosis in patients with Crohn's disease (CD). Methods: We analyzed a total of 37 (11 women; 23-69 years) patients with known biopsy proven CD, who underwent MR-enterography (MRE) study, performed on a 1.5 T MRI system (Achieva, Philips), using a phased array sense body multicoil, after oral administration of 1.5-2 L of PEG solution. MRE protocol included T1 weighted, SSh T2, sBTFE, and gadolinium-enhanced THRIVE sequences acquired on coronal and axial planes. A dedicated workstation was used to generate perfusion color maps, on which we drown ROI on normal bowel and on pathological segment, thus obtaining related perfusion parameters: relative arterial, venous, and late enhancement (RAE, RVE, and RLE), maximum enhancement (ME), and time to peak (TTP). Results: Quantitative perfusion analysis showed a good correlation with local degree of Crohn's inflammation activity. Twenty-nine out of 37 patients showed active inflammatory disease (reference standard of active disease: wall bowel thickness and layered enhancement) with following perfusion parameters: REA (%) = 116.1, RVE (%) = 125.3, RLE (%) = 127.1, ME (%) = 1054.7, TTP (sec) = 157. The same parameters calculated in patients with mural fibrosis were as follows: RAE (%): median = 56.4; RVE (%): 81.2; RLE (%): 85.4; ME (%):809.6; TTP (sec): 203.4. A significant difference (p < 0.001) between inflamed and fibrotic bowel wall vascularity, regarding all perfusion parameters evaluated, was found, with higher values in active CD localizations. Conclusion: Vascular assessment of perfusion kinetics of bowel wall by dynamic contrast perfusion-MR analysis may represent a complementary diagnostic tool that enables a quantitative evaluation of local inflammation activity in CD patients.

Real-Time Elastography: Noninvasive Diagnostic Tool in the Evaluation of Liver Stiffness in Patients with Chronic Viral Hepatitis, Correlation with Histological Examination.

PURPOSE: To determine the value of real-time elastography (RTE) in the assessment of liver stiffness in patients with chronic viral hepatitis, correlating RTE data with the extent of fibrosis based on biopsy findings (Ishak score). METHODS: We evaluated 98 patients (45-75 years) with chronic viral hepatitis (51 HCV, 47 HBV) by using ultrasonography (US) study combined with RTE analysis. In the RTE images, relative tissue stiffness is expressed, according to color scale, with soft areas represented in green/red colors and hard areas in blue. We divided the patients into 2 groups based on the fibrosis degree: soft degree (D1, corresponding to F1-F3 Ishak score) and hard degree (D2, corresponding to F4-F6). Before RTE, all patients underwent a US-guided percutaneous liver biopsy (right lobe). RESULTS: Quantitative RTE data were compared with liver biopsy by using the Spearman correlation coefficient in order to assess the correlation between the RTE (D) and fibrosis, according to Ishak score (F) at histology. At RTE, out of 98 patients 55 had degree D1 and 43 had degree D2; at histological analysis, we observed the following: 15 patients with F1, 28 with F2, 17 with F3, 16 with F4, 12 with F5, and 10 with F6. The Spearman's coefficient showed significant correlation between D and F degree, obtaining rho = 0.573, p = 0.003. CONCLUSIONS: RTE analysis showed high diagnostic accuracy in the assessment of fibrosis, and it appears to be a useful diagnostic tool for noninvasive quantification of fibrosis in patients with chronic viral hepatitis.

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.

Diagnostic accuracy of 256-row multidetector CT coronary angiography with prospective ECG-gating combined with fourth-generation iterative reconstruction algorithm in the assessment of coronary artery bypass: evaluation of dose reduction and image quality.

BACKGROUND: Effective radiation dose in coronary CT angiography (CTCA) for coronary artery bypass graft (CABG) evaluation is remarkably high because of long scan lengths. Prospective electrocardiographic gating with iterative reconstruction can reduce effective radiation dose. OBJECTIVES: To evaluate the diagnostic performance of low-kV CT angiography protocol with prospective ecg-gating technique and iterative reconstruction (IR) algorithm in follow-up of CABG patients compared with standard retrospective protocol. METHODS: Seventy-four non-obese patients with known coronary disease treated with artery bypass grafting were prospectively enrolled. All the patients underwent 256 MDCT (Brilliance iCT, Philips) CTCA using low-dose protocol (100 kV; 800 mAs; rotation time: 0.275 s) combined with prospective ECG-triggering acquisition and fourth-generation IR technique (iDose4; Philips); all the lengths of the bypass graft were included in the evaluation. A control group of 42 similar patients was evaluated with a standard retrospective ECG-gated CTCA (100 kV; 800 mAs).On both CT examinations, ROIs were placed to calculate standard deviation of pixel values and intra-vessel density. Diagnostic quality was also evaluated using a 4-point quality scale. RESULTS: Despite the statistically significant reduction of radiation dose evaluated with DLP (study group mean DLP: 274 mGy cm; control group mean DLP: 1224 mGy cm; P value < 0.001). No statistical differences were found between PGA group and RGH group regarding intra-vessel density absolute values and SNR. Qualitative analysis, evaluated by two radiologists in "double blind", did not reveal any significant difference in diagnostic quality of the two groups. CONCLUSIONS: The development of high-speed MDCT scans combined with modern IR allows an accurate evaluation of CABG with prospective ECG-gating protocols in a single breath hold, obtaining a significant reduction in radiation dose.

Diagnostic value of fourth-generation iterative reconstruction algorithm with low-dose CT protocol in assessment of mesorectal fascia invasion in rectal cancer: comparison with magnetic resonance.

PURPOSE: The purpose of the article is to compare the diagnostic performance about radiation dose and image quality of low-dose CT with iterative reconstruction algorithm (iDose4) and standard-dose CT in the assessment of mesorectal fascia (MRF) invasion in rectal cancer patients. MATERIALS AND METHODS: Ninety-one patients with biopsy-proven primary rectal adenocarcinoma underwent CT staging: 42 underwent low-dose CT, 49 underwent standard CT protocol. Low-dose contrast-enhanced MDCT scans were performed on a 256 (ICT, Philips) scanner using 120 kV, automated mAs modulation, iDose4 iterative reconstruction algorithm. Standard-dose MDCT scans were performed on the same scanner with 120 kV, 200-300 mAs. All patients underwent a standard lower abdomen MR study (on 1.5T magnet), including multiplanar sequences, considered as reference standard. Diagnostic accuracy of MRF assessment was determined on CT images for both CT protocols and compared with MRI images. Dose-length product (DLP) and CT dose index (CTDI) calculated for both groups were compared and statistically analyzed. RESULTS: Low-dose protocol with iDose4 showed high diagnostic quality in assessment of MRF with significant reduction (23%; p = 0.0081) of radiation dose (DLP 2453.47) compared to standard-dose examination (DLP 3194.32). CONCLUSIONS: Low-dose protocol combined with iDose4 reconstruction algorithm offers high-quality images, obtaining significant radiation dose reduction, useful in the evaluation of MRF involvement in rectal cancer patients.

Relative volume measured with magnetic resonance imaging is an articular collapse predictor in hematological pediatric patients with femoral head osteonecrosis.

AIM: To assess the potential value of femoral head (FH) volume measurements to predict joint collapse, as compared to articular surface involvement, in post-treatment osteonecrosis (ON) in pediatric patients affected by lymphoproliferative diseases. METHODS: Considering 114 young patients with lymphoproliferative diseases undergone a lower-limbs magnetic resonance imaging (MRI) examination between November 2006 and August 2012 for a suspected post-treatment ON, we finally considered a total of 13 cases (7 males, mean age 15.2 ± 4.8 years), which developed a FH ON lesions (n = 23). The MRI protocol included coronal short tau inversion recovery and T1-weighted sequences, from the hips to the ankles. During the follow-up (elapsed time: 9.2 ± 2 mo), 13/23 FH articular surface (FHS) developed articular deformity. The first MRI studies with diagnosis of ON were retrospectively analyzed, measuring FH volume (FHV), FHS, ON volume (ONV) and the articular surface involved by ON (ONS). The relative involvement of FHS, in terms of volume [relative volume (RV): ONV/FHV] and articular surface [relative surface (RS): ONS/FHS], was then calculated. RESULTS: By using receiver operating characteristic curve analysis (threshold of 23% of volume involvement), RV predicted articular deformity in 13/13 FHS [sensitivity 100%, specificity 90%, accuracy 95%, positive predictive value (PPV) 93%, negative predictive value (NPV) 100%]. Considering a threshold of 50% of articular involvement, RS predicted articular deformity in 10/13 femoral heads (sensitivity 77%, specificity 100%, accuracy 87%, PPV 100%, NPV 77%). CONCLUSION: RV might be a more reliable parameter than RS in predicting FH deformity and could represent a potential complementary diagnostic tool in the follow-up of femoral heads ON lesions.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging With Gadolinium Ethoxybenzyl Diethylenetriamine Pentaacetic Acid for Quantitative Assessment of Vascular Effects on Hepatocellular-Carcinoma Lesions Treated by Transarterial Chemoembolization or Radiofrequency Ablation.

PURPOSE: The aim of this study was to investigate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in evaluation of blood flow changes related to transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) procedures in patients with hepatocellular carcinoma (HCC) lesions. METHODS: Fifty-four patients, with biopsy-proven HCC, who underwent TACE or RFA, were evaluated, 1 month after treatment, with upper abdominal MRI examination. Multiplanar T2-weighted, T1-weighted, and dynamic contrast-enhanced sequences were acquired. Dedicated perfusion software (T1 Perfusion Package, Viewforum; Philips Medical Systems, The Netherlands) was used to generate color permeability maps. After placing regions of interest in normal hepatic parenchyma, in successfully treated lesions, and in area of recurrence, the following perfusion parameters were calculated and statistically analyzed: relative arterial, venous, and late enhancement; maximum enhancement; maximum relative enhancement, and time to peak. RESULTS: Twenty-one of 54 patients had residual disease, and perfusion parameters values measured within tumor tissue were: relative arterial enhancement median, 42%; relative venous enhancement median, 69%; relative late enhancement median, 57.7%; maximum enhancement median, 749.6%; maximum relative enhancement median, 69%; time to peak median, 81.1 seconds. As for all the evaluated parameters, a significant difference (P < 0.05) was found between residual viable tumor tissue and effective treated lesions. CONCLUSIONS: Dynamic contrast-enhanced MRI represents a complementary noninvasive tool that may offer quantitative and qualitative information about HCC lesions treated with TACE and RFA.

Intraobserver and Interobserver Agreement in the Evaluation of Tumor Vascularization With Computed Tomography Perfusion in Cirrhotic Patients With Hepatocellular Carcinoma.

OBJECTIVES: To evaluate intrareader and inter-reader agreement in CT perfusion (Perf) measurements in cirrhotic patients with hepatocellular carcinoma (HCC) lesions. METHODS: Sixteen patients with HCC (9 untreated, 5 recurrence/residual disease after transarterial chemoembolization, and 2 after radiofrequency ablation treatment) underwent standard CT examination and a Perf study; a quantitative map of arterial and portal Perf by means of a color scale was generated. With dedicated Perf software, the following parameters were calculated on untreated and treated HCC lesions and on cirrhotic parenchyma: hepatic Perf, tissue blood volume, hepatic perfusion index, arterial perfusion, and time to peak. Intraobserver and interobserver agreements were assessed for 2 readers with Bland-Altman plots, intraclass correlation coefficients (ICCs), coefficients of variation, and repeatability. RESULTS: In HCC lesions, agreement analysis demonstrated higher intra-agreement values in comparison with interagreement (range of ICC values, 0.26-0.59 between readers and 0.67-0.94 between readings). Lower interagreement was found for treated HCC lesions in comparison with untreated lesions (range of ICC values, respectively, 0.12-0.54 and 0.31-0.89). CONCLUSIONS: For all Perf parameters intra-agreement was higher than interagreement, even though a relatively wide range of 95% limits of agreement was found in both cases.

Apparent diffusion coefficient maps integrated in whole-body MRI examination for the evaluation of tumor response to chemotherapy in patients with multiple myeloma.

RATIONALE AND OBJECTIVES: To determine the diagnostic value of apparent diffusion coefficient (ADC) maps in the assessment of response to chemotherapy in patients with multiple myeloma (MM). MATERIALS AND METHODS: Fourteen patients (seven women) with MM underwent whole-body magnetic resonance imaging (WB-MRI) study on a 1.5T scanner, before and after chemotherapy. DWI with background body signal suppression (DWIBS) sequences (b values: 0, 500, and 1000 mm(2)/sec) were qualitatively analyzed, along with T1 turbo spine echo and short tau inversion recovery T2-weighted images, to evaluate bone lesions. On ADC maps, regions of interest were manually drawn along contours of lesions. The ADC values percentage variation (ΔADC) before (MR1) and after (MR2) chemotherapy were calculated and compared between responders (11 of 14) and nonresponders (3 of 14). The percentage of plasma cells by the means of the bone marrow aspirate was evaluated as parameter for response to chemotherapy. RESULTS: Twenty-four lesions, hyperintense on DWIBS as compared to normal bone marrow, were evaluated. In responder group, the mean ADC values were 0.63 ± 0.24 × 10(-3) mm(2)/s on MR1 and 1.04 ± 0.46 × 10(-3) mm(2)/s on MR2; partial or complete signal intensity decrease during follow-up on DWIBS was found along with a reduction of plasma cells infiltration in the bone marrow. The mean ADC values for nonresponders were 0.61 ± 0.05 × 10(-3) mm(2)/s on MR1 and 0.69 ± 0.09 × 10(-3) mm(2)/s on MR2. The mean variation of ΔADC in responders (Δ = 66%) was significantly different (P < .05) than in nonresponders (Δ = 15%). CONCLUSIONS: WB-MRI with DWIBS sequences, by evaluating posttreatment changes of ADC values, might represent a complementary diagnostic tool in the assessment of response to chemotherapy in MM patients.

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.

Semiquantitative perfusion combined with diffusion-weighted MR imaging in pre-operative evaluation of endometrial carcinoma: results in a group of 57 patients.

PURPOSE: To evaluate the semiquantitative DCE and quantitative DWI parameters in endometrial cancer, in order to assess the presence of neoplastic tissue and normal myometrium and to ascertain a potential relationship with tumor grade. METHODS AND MATERIALS: A total of 57 patients with biopsy-proven endometrial adenocarcinoma who underwent MR imaging examination for staging purposes were retrospectively evaluated. Imaging protocol included multiplanar T1- and T2-weighted TSE, DCE T1-weighted (THRIVE; 0, 30, 90 and 120seconds after intravenous injection of gadolinium) and DWIBS sequences (b values=0 and 1000mm(2)/s). Color perfusion and ADC maps were automatically generated on dedicated software. Relative enhancement (RE, %), maximum enhancement (ME, %), maximum relative enhancement (MRE, %), time to peak (TTP, s) and mean apparent diffusion coefficient (ADC) were calculated by manually drawing a region of interest (ROI) both on the neoplastic tissue and the normal myometrium. Histopathology was used as reference standard. RESULTS: Histopathological analysis confirmed the presence of endometrial carcinoma in all patients. Neoplastic tissue demonstrated significantly lower (P<0.001) values of RE (%) 63.92±35.68; ME (%) 864.91±429.54 and MRE (%) 75.97±38.26 as compared to normal myometrium (RE (%) 151.43±55.99; ME (%) 1800.73±721.32; MRE (%) 158.28±54.05). TTP was significantly higher (P<0.05) in tumor lesion (385.51±1630.27 vs 195.44±78.69). Mean ADC value of neoplastic tissue (775.09±?220.73×10(-3)mm(2)/s) was significantly lower (P<0.05) than in myometrium (1602.37±378.54×10(-3)mm(2)/s). The analysis of perfusion and diffusion parameters classified according to tumor grades, showed a statistically significant difference only for RE (P=0.043) and ME (P=0.007). CONCLUSIONS: Perfusion parameters and mean ADC differ significantly between endometrial cancer and normal myometrium, potentially reflecting the different microscopical features of cellularity and vascularity; however a significant relationship with tumor grade was not found in our series.

Quantitative assessment of tumour associated neovascularisation in patients with liver cirrhosis and hepatocellular carcinoma: role of dynamic-CT perfusion imaging.

OBJECTIVE: To determine the value of perfusion computed tomography (CT-p) in the quantitative assessment of tumour-related neoangiogenesis processes in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-two biopsy proven HCC lesions were examined with dynamic CT investigations during injection of 50 mL of contrast agent (350 mgI/mL). A dedicated perfusion software which generated a quantitative map of arterial and portal perfusion by means of a colour scale was employed. The following parameters related to the blood microcirculation and tissue perfusion were calculated: hepatic perfusion (Perf), tissue blood volume (BV), hepatic perfusion index (HPI), arterial perfusion (AP), portal perfusion (PP), and time to peak (TTP). Perfusion parameters were statistically analysed, comparing neoplastic lesions with cirrhotic parenchyma. RESULTS: Perf, BV, HPI and AP values were higher (P < 0.001), whereas PP and TTP were lower (P < 0.001) in HCC relative to the surrounding liver. No significant correlation was found between perfusion parameters and HCC grade. Values of perfusion parameters in the cirrhotic liver of patients with and without HCC were not significantly different. CONCLUSIONS: Our results suggest that CT-p can help in non-invasive quantification of tumour blood supply, related to the formation of new arterial structures (neoangiogenesis), which are essential for tumour growth. KEY POINTS: Perfusion computed tomography (CT) enables depiction of tumour vascular physiology. Perfusion CT is non-invasive and is now quick to perform and analyse. Quantitative measurements of hepatic perfusion provide important information about hepatocellular carcinoma (HCC). Such perfusion CT data may help in the determination of the outcome of HCC. Perfusion CT can act as an in-vivo biomarker of tumour-related angiogenesis.