The success of highly conformal radiotherapy techniques in the sparing of normal tissues or in dose escalation, or both, relies heavily on excellent imaging. Because of its superior soft tissue ...contrast, magnetic resonance imaging is increasingly being used in radiotherapy treatment planning. This review discusses the current clinical evidence to support the pivotal role of magnetic resonance imaging in radiation oncology.
To evaluate diffusion-weighted magnetic resonance imaging (DWI) for response prediction before and response assessment during and early after preoperative radiochemotherapy (RCT) for locally advanced ...rectal cancer (LARC).
Twenty patients receiving RCT for LARC underwent MRI including DWI before RCT, after 10-15 fractions and 1 to 2 weeks before surgery. Tumor volume and apparent diffusion coefficient (ADC; b-values: 0-1000 s/mm(2)) were determined at all time points. Pretreatment tumor ADC and volume, tumor ADC change (∆ADC), and volume change (∆V) between pretreatment and follow-up examinations were compared with histopathologic findings after total mesorectal excision (pathologic complete response pCR vs. no pCR, ypT0-2 vs. ypT3-4, T-downstaging or not). The discriminatory capability of pretreatment tumor ADC and volume, ∆ADC, and ∆V for the detection of pCR was compared with receiver operating characteristics analysis.
Pretreatment ADC was significantly lower in patients with pCR compared with patients without (in mm(2)/s: 0.94 ± 0.12 × 10(-3) vs. 1.19 ± 0.22 × 10(-3), p = 0.003), yielding a sensitivity of 100% and specificity of 86% for detection of pCR. The volume reduction during and after RCT was significantly higher in patients with pCR compared with patients without (in %: ΔV(during): -62 ± 16 vs. -33 ± 16, respectively, p = 0.015; and ΔV(post): -86 ± 12 vs. -60 ± 21, p = 0.012), yielding a sensitivity of 83% and specificity of 71% for the ΔV(during) and, respectively, 83% and 86% for the ΔV(post). The ∆ADC during (ΔADC(during)) and after RCT (ΔADC(post)) showed a significantly higher value in patients with pCR compared with patients without (in %: ΔADC(during): 72 ± 14 vs. 16 ± 12, p = 0.0006; and ΔADC(post): 88 ± 35 vs. 26 ± 19, p = 0.0011), yielding a sensitivity and specificity of 100% for the ΔADC(during) and, respectively, 100% and 93% for the ΔADC(post).
These initial findings indicate that DWI, using pretreatment ADC, ΔADC(during), and ΔADC(post) may be useful for prediction and early assessment of pathologic response to preoperative RCT of LARC, with higher accuracy than volumetric measurements.
Despite excellent per-lesion performance for peritoneal staging, the additional clinical value of diffusion-weighted magnetic resonance imaging (DWI/MRI) compared to computed tomography (CT) remains ...to be established in ovarian cancer.
Our purpose was to evaluate whole body (WB)-DWI/MRI for diagnosis, staging and operability assessment of patients suspected for ovarian cancer compared to CT.
One hundred and sixty-one patients suspected for ovarian carcinoma underwent 3 T WB-DWI/MRI and contrast-enhanced CT. WB-DWI/MRI and CT were compared for confirmation of the malignant nature and primary origin of the ovarian mass, Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) staging and prediction of incomplete resection using institutional operability criteria. Interobserver agreement between two readers was determined for WB-DWI/MRI and CT.
WB-DWI/MRI showed a significantly higher accuracy than CT (93 versus 82%, p = 0.001) to confirm the malignant nature of the ovarian mass and correctly identified 26 of 32 (81%) cancers of non-ovarian origin compared to 10/32 (31%) for CT (p < 0.001). WB-DWI/MRI assigned more ovarian carcinoma patients to the correct FIGO stage (82/94, 87%) compared with CT (33/94, 35%). For prediction of incomplete resection, WB-DWI/MRI showed significantly higher sensitivity (94 versus 66%), specificity (97.7 versus 77.3%) and accuracy (95.7 versus 71.3%) compared to CT (p < 0.001). Interobserver agreement was almost perfect (κ = 0.90) for WB-DWI/MRI and moderate (κ = 0.52) for CT for prediction of incomplete resection.
WB-DWI/MRI was superior to CT for primary tumour characterisation, staging and prediction of incomplete resection in patients suspected for ovarian cancer.
•Whole body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) improves primary tumour characterisation compared to computed tomography (CT).•WB-DWI/MRI detects surgically critical metastases significantly better than CT.•WB-DWI/MRI particularly improves detection of serosal and distant metastases.•WB-DWI/MRI is superior to CT for operability assessment in ovarian cancer.
•MRI radiomics predict the response to chemoradiation in patients with rectal cancer.•RMRI-based radiomics models do not outperform a four-feature semantic MRI model.•MRI models provide the potential ...for non-invasive selection of responding patients.•These findings can be used to tailor the treatment for patients with rectal cancer.
In well-responding patients to chemoradiotherapy for locally advanced rectal cancer (LARC), a watch-and-wait strategy can be considered. To implement organ-sparing strategies, accurate patient selection is needed. We investigate the use of MRI-based radiomics models to predict tumor response to improve patient selection.
Models were developed in a cohort of 70 patients and validated in an external cohort of 55 patients. Patients received chemoradiation followed by surgery and underwent T2-weighted and diffusion-weighted MRI (DW-MRI) before and after chemoradiation. The outcome measure was (near-)complete pathological tumor response (ypT0-1N0).
Tumor segmentation was done on T2-images and transferred to b800-images and ADC maps, after which quantitative and four semantic features were extracted. We combined features using principal component analysis and built models using LASSO regression analysis. The best models based on precision and performance were selected for validation.
21/70 patients (30%) achieved ypT0-1N0 in the development cohort versus 13/55 patients (24%) in the validation cohort. Three models (t2_dwi_pre_post, semantic_dwi_adc_pre, semantic_dwi_post) were identified with an area-under-the-curve (AUC) of 0.83 (95% CI 0.70–0.95), 0.86 (95% CI 0.75–0.98) and 0.84 (95% CI 0.75–0.94) respectively. Two models (t2_dwi_pre_post, semantic_dwi_post) validated well in the external cohort with AUCs of 0.83 (95% CI 0.70–0.95) and 0.86 (95% CI 0.76–0.97). These models however did not outperform a previously established four-feature semantic model.
Prediction models based on MRI radiomics non-invasively predict tumor response after chemoradiation for rectal cancer and can be used as an additional tool to identify patients eligible for an organ-preserving treatment.
Cholangiocellular carcinoma (CC) originates from topographically heterogeneous cholangiocytes. The cylindrical mucin‐producing cholangiocytes are located in large bile ducts and the cuboidal ...non–mucin‐producing cholangiocytes are located in ductules containing bipotential hepatic progenitor cells (HPCs). We investigated the clinicopathological and molecular features of 85 resected CCs (14 hilar CCs so‐called Klatskin tumor, 71 intrahepatic CCs ICCs including 20 cholangiolocellular carcinomas CLCs, which are thought to originate from HPCs) and compared these with the different cholangiocyte phenotypes, including HPCs. Immunohistochemistry was performed with biliary/HPC and hepatocytic markers. Gene expression profiling was performed in different tumors and compared with nonneoplastic different cholangiocyte phenotypes obtained by laser microdissection. Invasion and cell proliferation assay were assessed using different types of CC cell lines: KMC‐1, KMCH‐1, and KMCH‐2. Among 51 ICCs, 31 (60.8%) contained only mucin‐producing CC features (muc‐ICCs), whereas 39.2% displayed histological diversity: focal hepatocytic differentiation and ductular areas (mixed‐ICCs). Clinicopathologically, muc‐ICCs and hilar CCs showed a predominantly (peri‐)hilar location, smaller tumor size, and more lymphatic and perineural invasion compared with mixed‐ICCs and CLCs (predominantly peripheral location, larger tumor size, and less lymphatic and perineural invasion). Immunoreactivity was similar in muc‐ICCs and hilar CCs and in mixed‐ICCs and CLCs. S100P and MUC1 were significantly up‐regulated in hilar CCs and muc‐ICCs compared with mixed‐ICCs and CLCs, whereas NCAM1 and ALB tended to be up‐regulated in mixed‐ICCs and CLCs compared with other tumors. KMC‐1 showed significantly higher invasiveness than KMCH‐1 and KMCH‐2. Conclusion: Muc‐ICCs had a clinicopathological, immunohistochemical, and molecular profile similar to that of hilar CCs (from mucin‐producing cholangiocytes), whereas mixed‐ICCs had a profile similar to that of CLCs (thought to be of HPC origin), possibly reflecting their respective cells of origin. (HEPATOLOGY 2012;55:1876–1888)
To evaluate diffusion-weighted imaging (DWI) for assessment of treatment response in head and neck squamous cell carcinoma (HNSCC) three weeks after the end of chemoradiotherapy (CRT).
Twenty-nine ...patients with HNSCC underwent magnetic resonance imaging (MRI) prior to and 3 weeks after CRT, including T(2)-weighted and pre- and postcontrast T(1)-weighted sequences and an echo-planar DWI sequence with six b values (0 to 1,000 s/mm(2)), from which the apparent diffusion coefficient (ADC) was calculated. ADC changes 3 weeks posttreatment compared to baseline (∆ADC) between responding and nonresponding primary lesions and adenopathies were correlated with 2 years locoregional control and compared with a Mann-Whitney test. In a blinded manner, the ∆ADC was compared to conventional MRI 3 weeks post-CRT and the routinely implemented CT, on average 3 months post-CRT, which used size-related and morphological criteria. Positive and negative predictive values (PPV and NPV, respectively) were compared between the ∆ADC and anatomical imaging.
The ∆ADC of lesions with later tumor recurrence was significantly lower than lesions with complete remission for both primary lesions (-2.3% ± 0.3% vs. 80% ± 41%; p < 0.0001) and adenopathies (19.9% ± 32% vs. 63% ± 36%; p = 0.003). The ∆ADC showed a PPV of 89% and an NPV of 100% for primary lesions and a PPV of 70% and an NPV of 96% for adenopathies per neck side. DWI improved PPV and NPV compared to anatomical imaging.
DWI with the ∆ADC 3 weeks after concluding CRT for HNSCC allows for early assessment of treatment response.
Purpose
In 10–24% of patients with rectal cancer who are treated with neoadjuvant chemoradiation, no residual tumor is found after surgery (ypT0). When accurately selected, these complete responders ...might be considered for less invasive treatments instead of standard surgery. So far, no imaging method has proven reliable. This study was designed to assess the accuracy of diffusion-weighted MRI (DWI) in addition to standard rectal MRI for selection of complete responders after chemoradiation.
Methods
A total of 120 patients with locally advanced rectal cancer from three university hospitals underwent chemoradiation followed by a restaging MRI (1.5T), consisting of standard T2W-MRI and DWI (b0-1000). Three independent readers first scored the standard MRI only for the likelihood of a complete response using a 5-point confidence score, after which the DWI images were added and the scoring was repeated. Histology (ypT0 vs. ypT1-4) was the standard reference. Diagnostic performance for selection of complete responders and interobserver agreement were compared for the two readings.
Results
Twenty-five of 120 patients had a complete response (ypT0). Areas under the ROC-curve for the three readers improved from 0.76, 0.68, and 0.58, using only standard MRI, to 0.8, 0.8, and 0.78 after addition of DWI (
P
= 0.39, 0.02, and 0.002). Sensitivity for selection of complete responders ranged from 0–40% on standard MRI versus 52–64% after addition of DWI. Specificity was equally high (89–98%) for both reading sessions. Interobserver agreement improved from κ 0.2–0.32 on standard MRI to 0.51–0.55 after addition of DWI.
Conclusions
Addition of DWI to standard rectal MRI improves the selection of complete responders after chemoradiation.
To investigate the prognostic value of baseline imaging features for overall survival (OS) and liver decompensation (LD) in patients with hepatocellular carcinoma (HCC).
Patients with advanced HCC ...from the SORAMIC trial were evaluated in this post hoc analysis. Several radiological imaging features were collected from baseline computed tomography (CT) and magnetic resonance imaging (MRI) imaging, besides clinical values. The prognostic value of these features for OS and LD (grade 2 bilirubin increase) was quantified with univariate Cox proportional hazard models and multivariate Least Absolute Shrinkage and Selection Operator (LASSO) regression.
Three hundred and seventy-six patients were included in this study. The treatment arm was not correlated with OS. LASSO showed satellite lesions, atypical HCC, peritumoral arterial enhancement, larger tumour size, higher albumin-bilirubin (ALBI) score, liver-spleen ratio <1.5, ascites, pleural effusion and higher bilirubin values were predictors of worse OS, and higher relative liver enhancement, smooth margin and capsule were associated with better OS. LASSO analysis for LD showed satellite lesions, peritumoral hypointensity in hepatobiliary phase, high ALBI score, higher bilirubin values and ascites were predictors of LD, while randomisation to sorafenib arm was associated with lower LD.
Imaging features showing aggressive tumour biology and poor liver function, in addition to clinical parameters, can serve as imaging biomarkers for OS and LD in patients receiving sorafenib and selective internal radiation therapy for HCC.
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