Immune response evaluation criteria in solid tumors for assessment of atypical responses after immunotherapy.

In 2017, immune response evaluation criteria in solid tumors (iRECIST) were introduced to validate radiologic and clinical interpretations and to better analyze tumor's response to immunotherapy, considering the different time of following and response, between this new therapy compared to the standard one. However, even if the iRECIST are worldwide accepted, to date, different aspects should be better underlined and well reported, especially in clinical practice. Clinical experience has demonstrated that in a non-negligible percentage of patients, it is challenging to determine the correct category of response (stable disease, progression disease, partial or complete response), and consequently, to define which is the best management for those patients. Approaching radiological response in patients who underwent immunotherapy, a new uncommon kind of target lesions behavior was found. This phenomenon is mainly due to the different mechanisms of action of immunotherapeutic drug. Therefore, new groups of response have been described in clinical practice, defined as "atypical responses," and categorized into three new groups: pseudoprogression, hyperprogression, and dissociated response. This review summarizes and reports these patterns, helping clinicians and radiologists get used to atypical responses, in order to identify patients that respond best to treatment.

Whole-body low-dose computed tomography (WBLDCT) in staging and re-staging of multiple myeloma.

The objective of this study is to evaluate the prognostic features of multiple myeloma (MM) using whole-body low-dose computed tomography (WBLDCT). One hundred three patients with biopsy-proven MM who underwent WBLDCT were retrospectively enrolled. The evolution of osteolytic lesions overtime was performed by measuring the maximum axial diameter at the baseline (T0) and the end of follow-up (Te), by using a cut-off value of 10 mm. The location and dimension of up to three lesions were registered. The time-to-fracture (TTF) was recorded. Sixty-three percent of patients presented a focal pattern, 22% a diffuse pattern, and 15% a combined one. Seventy-two percent of patients with lesions ≤ 10 mm presented stability, 27% a dimensional increase, and 1% a decrease. Patients with lesions >10 mm showed a statistically significant difference regarding the mean difference of axial diameter between T0 and Te (p = 0.015). Patients with lesions >10 mm showed an odds ratio (OR) of 29.8 (95%CIs 3.8-230.5) to develop at least one fracture. Mean TTF was significantly lower in patients with lesions >10 mm in comparison with lesions ≤ 10 mm (9 ± 3 vs 23 ± 7 months, respectively, p = 0.011). WBLDCT represents a reliable imaging-based tool for proper management of MM patients, showing that diffuse form or small lytic lesions may deserve a less frequent follow-up.

Role of dynamic perfusion magnetic resonance imaging in patients with local advanced rectal cancer.

BACKGROUND: The management of rectal cancer patients is mainly based on the use of the magnetic resonance imaging (MRI) technique as a diagnostic tool for both staging and restaging. After treatment, to date, the evaluation of complete response is based on the histopathology assessment by using different tumor regression grade (TRG) features (e.g., Dworak or Mandard classifications). While from the radiological point of view, the main attention for the prediction of a complete response after chemotherapy treatment focuses on MRI and the potential role of diffusion-weighted images and perfusion imaging represented by dynamic-contrast enhanced MRI. The main aim is to find a reliable tool to predict tumor response in comparison to histopathologic findings. AIM: To investigate the value of dynamic contrast-enhanced perfusion-MRI parameters in the evaluation of the healthy rectal wall and tumor response to chemo-radiation therapy in patients with local advanced rectal cancer with histopathologic correlation. METHODS: Twenty-eight patients with biopsy-proven rectal adenocarcinoma who underwent a dynamic contrast-enhanced MR study performed on a 1.5T MRI system (Achieva, Philips), before (MR1) and after chemoradiation therapy (MR2), were enrolled in this study. The protocol included T1 gadolinium enhanced THRIVE sequences acquired on axial planes. A dedicated workstation was used to generate color permeability maps. Region of interest was manually drawn on tumor tissue and normal rectal wall, hence the following parameters were calculated and statistically analyzed: Relative arterial enhancement (RAE), relative venous enhancement (RVE), relative late enhancement (RLE), maximum enhancement (ME), time to peak and area under the curve (AUC). Perfusion parameters were related to pathologic TRG (Mandard's criteria; TRG1 = complete regression, TRG5 = no regression). RESULTS: Ten tumors (36%) showed complete or subtotal regression (TRG1-2) at histology and classified as responders; 18 tumors (64%) were classified as non-responders (TRG3-5). Perfusion MRI parameters were significantly higher in the tumor tissue than in the healthy tissue in MR1 (P < 0.05). At baseline (MR1), no significant difference in perfusion parameters was found between responders and non-responders. After chemo-radiation therapy, at MR2, responders showed significantly (P < 0.05) lower perfusion values [RAE (%) 54 ± 20; RVE (%) 73 ± 24; RLE (%): 82 ± 29; ME (%): 904 ± 429] compared to non-responders [RAE (%): 129 ± 45; RVE (%): 154 ± 39; RLE (%): 164 ± 35; ME (%): 1714 ± 427]. Moreover, in responders group perfusion values decreased significantly at MR2 [RAE (%): 54 ± 20; RVE (%): 73 ± 24; RLE (%): 82 ± 29; ME (%): 904 ± 429] compared to the corresponding perfusion values at MR1 [RAE (%): 115 ± 21; RVE (%): 119 ± 21; RLE (%): 111 ± 74; ME (%): 1060 ± 325]; (P < 0.05). Concerning the time-intensity curves, the AUC at MR2 showed significant difference (P = 0.03) between responders and non-responders [AUC (mm2 × 10-3) 121 ± 50 vs 258 ± 86], with lower AUC values of the tumor tissue in responders compared to non-responders. In non-responders, there were no significant differences between perfusion values at MR1 and MR2. CONCLUSION: Dynamic contrast perfusion-MRI analysis represents a complementary diagnostic tool for identifying vascularity characteristics of tumor tissue in local advanced rectal cancer, useful in the assessment of treatment response.

Chest X-ray features of SARS-CoV-2 in the emergency department: a multicenter experience from northern Italian hospitals.

OBJECTIVES: To evaluate the imaging features of routine admission chest X-ray in patients referred for novel Coronavirus 2019 infection. METHODS: All patients referred to the emergency departments, RT-PCR positive for SARS-CoV-2 infection were evaluated. Demographic and clinical data were recorded. Two radiologists (8 and 15 years of experience) reviewed all the X-ray images and evaluated the following findings: interstitial opacities, alveolar opacities (AO), AO associated with consolidation, consolidation and/or pleural effusion. We stratified patients in groups according to the time interval between symptoms onset (cut-off 5 days) and X-ray imaging and according to age (cut-off 60 years old). Computed tomography was performed in case of a discrepancy between clinical symptoms, laboratory and X-ray findings, and/or suspicion of complications. RESULTS: A total of 468 patients were tested positive for SARS-CoV-2. Lung lesions primarily manifested as interstitial opacities (71.7%) and AO opacities (60.5%), more frequently bilateral (64.5%) and with a peripheral predominance (62.5%). Patients admitted to the emergency radiology department after 5 days from symptoms onset, more frequently had interstitial and AO opacities, in comparison to those admitted within 5 days, and lung lesions were more frequently bilateral and peripheral. Older patients more frequently presented interstitial and AO opacities in comparison to younger ones. Sixty-eight patients underwent CT that principally showed the presence of ground-glass opacities and consolidations. CONCLUSIONS: The most common X-ray pattern is multifocal and peripheral, associated with interstitial and alveolar opacities. Chest X-ray, compared to CT, can be considered a reliable diagnostic tool, especially in the Emergency setting.

Dynamic Computed Tomography Perfusion Imaging: Complementary Diagnostic Tool in Hepatocellular Carcinoma Assessment From Diagnosis to Treatment Follow-up.

Early diagnosis of HCC is of paramount importance in order to enable the application of curative treatments. Among these, radiofrequency ablation (RFA) is actually considered the most effective ablative therapy for early stage hepatocellular carcinoma (HCC) not suitable for surgery. On the other hand, transarterial chemoembolization (TACE) represents the standard of care for intermediate stage HCC and compensated liver function. Finally, sorafenib, an oral antiangiogenic targeted drug, is the only approved systemic therapy for advanced HCC with vascular invasion, extrahepatic spread, and well-preserved liver function. Beside traditional radiological techniques, new functional imaging tools have been introduced in order to provide not only morphological information but also quantitative functional data. In this review, we analyze perfusion-CT (pCT) from a technical point of view, describing the main different mathematical analytical models for the quantification of tissue perfusion from acquired CT raw data, the most commonly acquired perfusion parameters, and the technical parameters required to perform a standard pCT examination. Moreover, a systematic review of the literature was performed to assess the role of pCT as an emerging imaging biomarker for HCC diagnosis, response evaluation to RFA, TACE, and sorafenib, and we examine its challenges in HCC management.

Evaluation of image quality and radiation dose saving comparing knowledge model-based iterative reconstruction on 80-kV CT pulmonary angiography (CTPA) with hybrid iterative reconstruction on 100-kV CT.

OBJECTIVES: To evaluate dose reduction and image quality of 80-kV CT pulmonary angiography (CTPA) reconstructed with knowledge model-based iterative reconstruction (IMR), and compared with 100-kV CTPA with hybrid iterative reconstruction (iDose4). MATERIALS AND METHODS: One hundred and fifty-one patients were prospectively investigated for pulmonary embolism; a study group of 76 patients underwent low-kV setting (80 kV, automated mAs) CTPA study, while a control group of 75 patients underwent standard CTPA protocol (100 kV; automated mAs); all patients were examined on 256 MDCT scanner (Philips iCTelite). Study group images were reconstructed using IMR while the control group ones with iDose4. CTDIvol, DLP, and ED were evaluated. Region of interests placed in the main pulmonary vessels evaluated vascular enhancement (HU); signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. RESULTS: Compared to iDose4-CTPA, low-kV IMR-CTPA presented lower CTDIvol (6.41 ± 0.84 vs 9.68 ± 3.5 mGy) and DLP (248.24 ± 3.2 vs 352.4 ± 3.59 mGy × cm), with ED of 3.48 ± 1.2 vs 4.93 ± 1.8 mSv. Moreover, IMR-CTPA showed higher values of attenuation (670.91 ± 9.09 HU vs 292.61 ± 15.5 HU) and a significantly higher SNR (p < 0.0001) and CNR (p < 0.0001).The subjective image quality of low-kV IMR-CTPA was also higher compared with iDose4-CTPA (p < 0.0001). CONCLUSIONS: Low-dose CTPA (80 kV and automated mAs modulation) reconstructed with IMR represents a feasible protocol for the diagnosis of pulmonary embolism in the emergency setting, achieving high image quality with low noise, and a significant dose reduction within adequate reconstruction times(≤ 120 s).

"Hyperdense artery sign" in early ischemic stroke: diagnostic value of model-based reconstruction approach in comparison with standard hybrid iterative reconstruction algorithm.

PURPOSE: Hyperdense artery sign is the earliest sign of ischemic stroke on non-enhanced computed tomography and it can be visible long before parenchymal changes. The aim of our study was to compare diagnostic value of model-based iterative reconstruction algorithm (IMR) with that of iterative reconstruction algorithm (iDose4) in identifying hyperdense artery sign. METHODS: We selected 56 consecutive patients suspected for ischemic stroke, who underwent a NCCT and that demonstrated a vessel occlusion at angio-CT or developed ischemic lesion at follow-up CT. Two readers randomly analyzed images of NCCT reconstructed both with iDose4 (4 mm) and IMR (2 mm), reporting presence of hyperdense artery sign (0: no; 1: yes; 2: not sure). They rated image quality on a 4-point scale (1: unacceptable; 4: more than average) and recorded HU values of clot and of normal vessel and measured noise index, CNR and SNR. RESULTS: Mean values of CTDI, DLP, and ED were respectively of 43 mGy, 819.7 mGy cm, and 1.72 mSv. By analyzing the IMR reconstruction, both readers were able to recognize hyperdense vessel sign in 55/56 patients, while only in 12/56 patients were identified with iDose. IMR obtained better rating of image quality (mean score for IMR 3.32 vs 2.53 for iDose), higher clot density (57.2 vs 46.7 HU), lower noise index (5 vs 2), higher CNR and SNR (respectively 4.2 vs 2 and 16.8 vs 8.5). CONCLUSIONS: Model-based approach significantly increases sensitivity in detecting hyperdense artery sign, offering higher SNR and CNR in brain CT images in comparison with standard hybrid reconstruction algorithm.

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 dynamic contrast-enhanced CT with perfusion imaging in the quantitative assessment of tumor response to sorafenib in patients with advanced hepatocellular carcinoma: A feasibility study.

PURPOSE: To investigate the feasibility of perfusion-CT (p-CT) measurements in quantitative assessment of hemodynamic changes related to sorafenib in patients with advanced hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty-two patients with advanced HCC underwent p-CT study (256-MDCT scanner) before and 2 months after sorafenib administration. Dedicated perfusion software generated a quantitative map of arterial and portal perfusion and calculated the following perfusion parameters in target liver lesion: hepatic perfusion (HP), time-to-peak (TTP), blood volume (BV), arterial perfusion (AP), and hepatic perfusion index (HPI). After the follow-up scan, patients were categorized as responders and non-responders, according to mRECIST. Perfusion values were analyzed and compared in HCC lesions and in the cirrhotic parenchyma (n=22), such as between baseline and follow-up in progressors and non-progressors. RESULTS: Before treatment, all mean perfusion values were significantly higher in HCC lesions than in the cirrhotic parenchyma (HP 47.8±17.2 vs 13.3±6.3mL/s per 100g; AP 47.9±18.1 vs 12.9±10.7mL/s; p<0.001). The group that responded to sorafenib (n=17) showed a significant reduction of values in HCC target lesions after therapy (HP 29.2±23.3 vs 48.1±15.1; AP 29.4±24.6 vs 49.2±17.4; p<0.01), in comparison with the non-responder group (n=5) that demonstrated no significant variation before and after treatment of HP (46.9±25.1 vs 46.7±24.1) and AP (43.4±21.7 vs 43.5±24.6). Among the responder group, HP percentage variation (Δ) in target lesions, during treatment, showed a significantly different (p=0.04) ΔHP in the group with complete response (79%) compared to the group with partial response or stable disease (16%). CONCLUSIONS: p-CT technique can be used for HCC quantitative assessment of changes related to anti-angiogenic therapy. Identification of response predictors might help clinicians in selection of patients who may benefit from targeted-therapy allowing for optimization of individualized treatment.

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.

CT enterography: Diagnostic value of 4th generation iterative reconstruction algorithm in low dose studies in comparison with standard dose protocol for follow-up of patients with Crohn's disease.

PURPOSE: To compare radiation dose, image quality and diagnostic performance of low dose CT enterography (CTE) protocol combined with iterative reconstruction algorithm (iDose(4)) with standard dose CTE in follow-up of patients with known Crohn's disease (CD). MATERIALS AND METHOD: Thirty-six patients (12 females), with CD underwent a low-dose CTE scan during single venous phase on 256 MDCT scanner, with the following parameters: 120 kV, automated mAs dose-modulation, slice thickness 2mm and iDose(4) iterative reconstruction algorithm. A control group of thirty-seven patients underwent standard dose CTE examination on the same CT scanner. Two radiologists, blinded to clinical and pathological findings, independently evaluated in each scan, HU values in bowel wall and any presence of CD activity features and disease complications. Image noise and diagnostic quality were evaluated using a 4-point scale. Dose-length product (DLP) and CT-dose-index (CTDI) were recorded and data from both examinations were compared and statistically analyzed. RESULTS: Low-dose CTE protocol showed high diagnostic quality in assessment of Crohn's disease obtaining significantly (p ≤ 0.001) lower values of DLP and CTDI (604.98 mGy*cm and 12.29 mGy) as compared to standard dose examinations (974.85 mGy*cm and 19.71 mGy), with an overall dose reduction of 37.6%. Noise resulted slightly higher in iDose(4) images (SD=15.97) than in standard dose ones (SD=13.61) but this difference was not statistically significant (p=0.064). CONCLUSION: Low-dose CTE combined with iDose(4) reconstruction algorithm offers high quality images with significant reduction of radiation dose, and therefore can be considered a useful tool in the management of CD patients, considering their young age and the frequent imaging follow-up required.

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.

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 (Mandard's criteria; TRG1 = complete regression, TRG5 = no regression). RESULTS: After completion of therapy, all the patients were submitted to surgery. According to the Mandard's 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.

Endometrial cancer: correlation of apparent diffusion coefficient with tumor grade, depth of myometrial invasion, and presence of lymph node metastases.

OBJECTIVE: The objective of our study was to investigate whether apparent diffusion coefficient (ADC) values of endometrial cancer differ from those of normal endometrium and myometrium and whether they vary according to histologic tumor grade, the depth of myometrial invasion, or lymph node status. SUBJECTS AND METHODS: Seventy patients with histologically proved endometrial cancer and 36 control subjects with normal endometrium were enrolled in this prospective study. T2-weighted, dynamic T1-weighted, and diffusion-weighted images with b values of 0 and 1000 s/mm(2) were obtained of all patients. The ADC values of endometrial cancer, normal endometrium, and normal myometrium were recorded. Tumor grade, the depth of myometrial invasion, and lymph node status were assessed at postoperative histopathologic analysis. RESULTS: The mean (± SD) ADC value (10(-3) mm(2)/s) of endometrial cancer (0.77 ± 0.12) was significantly lower than that of normal endometrium (1.31 ± 0.11, p < 0.0001) and normal myometrium (1.52 ± 0.21, p < 0.0001), with no overlap between the two former distributions. There was no significant difference between ADC values of endometrial cancer tissue in patients with tumor grade 1 (0.79 ± 0.08, n = 14), grade 2 (0.76 ± 0.14, n = 40), or grade 3 (0.75 ± 0.12, n = 16) (p = 0.67); in patients with deep (0.77 ± 0.13, n = 18) and those with superficial (0.76 ± 0.12, n = 52) myometrial invasion (p = 0.87); and in patients with (0.78 ± 0.10, n = 6) and those without (0.75 ± 0.14, n = 39) lymph node metastases (p = 0.64). CONCLUSION: ADC values allow normal endometrium to be differentiated from endometrial carcinoma; however, they do not correlate with histologic tumor grade, the depth of myometrial invasion, or whether lymph node metastases are present.