Addition Of Diffusion-weighted Magnetic Resonance Imaging Research Articles

Role of diffusion-weighted MRI in diagnosis and post therapeutic follow-up of colorectal cancer

BackgroundThe colorectal cancer (CRC) is one of the deadliest cancers in the world. Local tumor stage, vascular or lymphatic invasion, and tumor grade are essential for accurate management. The main imaging modality for initial assessment and therapeutic response evaluation of CRC is magnetic resonance imaging (MRI). The purpose of this prospective study was to illustrate the role of diffusion-weighted MRI (DWI) and apparent diffusion coefficient (ADC) value in initial assessment and grading of colorectal carcinoma as well as evaluation of its response to chemotherapy or combined chemoradiation.ResultsRestricted diffusion in DWI was found in 37 out of 40 patients with sensitivity of about 92.5%. In the studied group, the median ADC value was 1.21 (min 0.80, max 1.31) and the average ADC value was 1.14 ± 0.161. The mean ADC value in poorly differentiated tumors was 0.979 × 10−3mm2/s. The mean ADC value in moderately differentiated tumors was 1.112 × 10−3mm2/s. The mean ADC value in well-differentiated tumors was 1.273 × 10−3mm2/s. The sensitivity, specificity, PPV, NPV, and accuracy were higher with addition of DWI and ADC value to conventional MRI reaching 100%, 80%, 83.3%, 100%, and 90%, respectively.ConclusionAdding DW imaging with ADC value to conventional MRI yields better diagnostic accuracy than using conventional MR imaging alone in detection, correlation with tumor histologic grade, initial staging, and response evaluation to neoadjuvant chemoradiotherapy in patients with locally advanced colorectal cancer.

Pelvic insufficiency fracture or bone metastasis after radiotherapy for cervical cancer? The added value of DWI for characterization.

We sought to determine the added value of diffusion-weighted magnetic resonance imaging (DWI) in the differentiation of pelvic insufficiency fracture (PIF) from bone metastasis after radiotherapy in cervical cancer patients. In the present study, 42 cervical cancer patients after radiotherapy with 61 bone lesions (n = 40, PIFs; n = 21, bone metastasis) were included. Conventional MRI and DWI were performed in all patients. For qualitative imaging diagnosis, two sets of images were reviewed independently by three observers, including a conventional MRI set (unenhanced T1-weighted, T2-weighted, and enhanced T1-weighted images) and a DWI set (conventional MRIs, DW images, and ADC maps). The mean ADC value of each lesson was measured on ADC maps. The diagnostic performance was assessed by using the area under the receiver operating characteristic curve (Az), and sensitivity and specificity were determined. For all observers, the Az value and sensitivity of the DWI set showed improvement compared with the conventional MRI set. The observer who had the least experience (3 years) demonstrated significant improvement in diagnostic performance with the addition of DWI; Az value increased from 0.804 to 0.915 (p = 0.042) and sensitivity increased from 75.0 to 92.5% (p = 0.035). The mean ADCs of the PIFs were significantly higher than the bone metastases (p < 0.001); ADC values > 0.97 × 10-3 mm2/s yielded an Az of 0.887, a sensitivity of 92.5%, and a specificity of 76.2%. The addition of DWI to conventional MRI improved the differentiation of PIF from bone metastasis after RT in patients with cervical cancer. • DWI showed additive value to conventional MRI in the differentiation of PIF from bone metastasis after RT. • For qualitative diagnosis, the addition of DWI can improve diagnostic performance compared with conventional MRI alone and can particularly improve the sensitivity. • Quantitative ADC assessment showed potential value for identifying PIF from bone metastasis.

Use of Functional Magnetic Resonance Imaging in Cervical Cancer Patients With Incomplete Response on Positron Emission Tomography/Computed Tomography After Image-Based High-Dose-Rate Brachytherapy

Toinvestigate the correlation between positron emission tomography/computed tomography (PET/CT) response and outcome in the era of magnetic resonance imaging (MRI)-based planning and to assess whether the addition of diffusion-weighted MRI (DW-MRI) could more accurately classify treatment response and prognosis. A retrospective chart review identified 244 consecutive patients with International Federation of Gynecology and Obstetrics stage IB1-IVA cervical cancer treated with concurrent chemoradiation, including high-dose-rate image-based brachytherapy, between 2007 and 2016. Image-based brachytherapy was delivered with 5 intracavitary/interstitial fractions, each 5 to 6Gy per fraction. An complete response on posttreatment PET/CT (PET-CR) was discovered in 50 of 244 patients (20%) at a median interval of 3.3months (range, 2.1-7.7months) after treatment. After a median follow-up of 27months, 2-year overall survival was 83% in all patients. Metabolic response significantly impacted 2-year overall survival (94% complete response on posttreatment PET/CT vs 62.4% PET-IR, P<.001). Of those with a PET-IR, 16 of 50 patients (32%) suffered a local recurrence. A total of 27 of 50 patients with a PET-IR underwent DW-MRI; 11 of 27 posttreatment DW-MRI scans (40%) were interpreted as positive by central review (median apparent diffusion coefficient of 0.973×10-3mm2/s). Of the DW-MRI-positive patients, 9 of 11 (81.8%) suffered a histologically confirmed local recurrence, and 2 of 11 patients are without evidence of disease. Additionally, 16 of 27 DW-MRI studies were interpreted as negative, and 2 of 16 (12.5%) of these patients suffered a local recurrence. Diffusion-weighted MRI findings significantly impacted 2-year overall survival (83% negative DW-MRI vs 36% positive DW-MRI, P=.049). Incomplete PET/CT response was documented in 20% of patients after image-based brachytherapy for locally advanced cervical cancer. Integration of DW-MRI helped accurately identify patients at risk for persistent disease and worse long-term outcome. The value of DW-MRI requires further validation in a large prospective dataset as this modality may allow earlier evaluation and salvage treatment in those with PET-IR.

Apparent diffusion coefficient by diffusion-weighted magnetic resonance imaging as a sole biomarker for staging and prognosis of gastric cancer.

ObjectiveTo investigate the role of apparent diffusion coefficient (ADC) from diffusion-weighted magnetic resonance imaging (DW-MRI) when applied to the 7th TNM classification in the staging and prognosis of gastric cancer (GC).MethodsBetween October 2009 and May 2014, a total of 89 patients with non-metastatic, biopsy proven GC underwent 1.5T DW-MRI, and then treated with radical surgery. Tumor ADC was measured retrospectively and compared with final histology following the 7th TNM staging (local invasion, nodal involvement and according to the different groups — stage I, II and III). Kaplan-Meier curves were also generated. The follow-up period is updated to May 2016.ResultsMedian follow-up period was 33 months and 45/89 (51%) deaths from GC were observed. ADC was significantly different both for local invasion and nodal involvement (P<0.001). Considering final histology as the reference standard, a preoperative ADC cut-off of 1.80×10–3 mm2/s could distinguish between stages I and II and an ADC value of ≤1.36×10–3 mm2/s was associated with stage III (P<0.001). Kaplan-Meier curves demonstrated that the survival rates for the three prognostic groups were significantly different according to final histology and ADC cut-offs (P<0.001). ConclusionsADC is different according to local invasion, nodal involvement and the 7th TNM stage groups for GC, representing a potential, additional prognostic biomarker. The addition of DW-MRI could aid in the staging and risk stratification of GC.

Lacrimal gland lesions: Can addition of diffusion-weighted MR imaging improve diagnostic accuracy in characterization?

The aim of the workTo evaluate the diagnostic value of apparent diffusion coefficient (ADC) maps in the characterization of lacrimal gland lesions. Material and methodsA retrospective study was conducted on 40 patients (26 female and 14 male subjects aged 13–74years) with lacrimal gland mass. They underwent echo-planar diffusion-weighted magnetic resonance imaging (MRI) of the orbit with a b-factor of 0500 and 1000s/mm2 at 3-Tesla magnetic resonance (MR) unit. ADC maps were reconstructed and the ADC of each mass lesion was calculated. Lesion diagnosis was confirmed by the clinical follow-up or the results of histopathology analysis depending on the specific disease to identify the specificity, sensitivity and accuracy of diffusion-weighted imaging (DWI) in the differentiation between benign and malignant lacrimal lesions. ResultsForty-two lesions were detected in the examined 40 patients included in this study. Thirty-one were benign and 11 were malignant. The mean ADC value of the malignant lacrimal tumors (0.76±0.14×10−3mm2/s) was significantly (P=0.001) lower than that of the benign lacrimal lesions (1.17±0.22×10−3mm2/s). A statistically significant (P=0.001) difference is identified between the subjects with lacrimal adenitis and those with idiopathic orbital inflammatory syndrome (orbital pseudotumor). Lacrimal lymphoma has the lowest ADCs among a wide range of lacrimal masses. The selection of an ADC value of 0.90×10−3mm2/s as a threshold value for differentiating malignant tumors from benign lacrimal lesions has an accuracy of 90%, a sensitivity of 90%, and specificity of 89%. ConclusionADC offers a useful reliable safe non-invasive imaging parameter that can be used for the differentiation of malignant tumors from benign lacrimal lesions with high sensitivity and specificity. The absence of contrast media in DWI reduces the cost of the examination and leads to an increase in the overall accuracy of MRI, hence reducing the number of false positive results and consequently reducing the number of unnecessary biopsies.

Parotid Gland Tumors: Can Addition of Diffusion-weighted MR Imaging to Dynamic Contrast-enhanced MR Imaging Improve Diagnostic Accuracy in Characterization?

To determine the value of adding diffusion-weighted (DW) magnetic resonance (MR) imaging to dynamic contrast material-enhanced MR imaging when distinguishing between benign and malignant parotid tumors. This retrospective study was approved by the institutional review board, and the informed consent requirement was waived. The authors analyzed MR images of 50 lesions (36 benign, 14 malignant) in 47 patients. DW MR imaging and dynamic contrast-enhanced MR imaging were performed in all patients. Time-intensity curve (TIC) patterns were categorized as follows: type A, time to peak was more than 120 seconds; type B, time to peak was 120 seconds or less with high washout ratio (> or = 30%); type C, time to peak was 120 seconds or less with low washout ratio (< 30%); and type D, flat. The apparent diffusion coefficient (ADC) values were measured on DW MR images. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for type A, B, and D tumors regarded as benign and for type C tumors regarded as malignant. On the basis of DW MR imaging results, ADC threshold values between pleomorphic adenomas and carcinomas and between Warthin tumors and carcinomas were selected. Diagnostic accuracy was compared before and after modification diagnosis referring to the ADC value obtained with the McNemar test. P < .05 was considered to indicate a significant difference. ADC threshold values were 1.4 x 10(-3) mm(2)/sec between pleomorphic adenomas and carcinomas and 1.0 x 10(-3) mm(2)/sec between Warthin tumors and carcinomas. Accuracy (82% vs 94%) and positive predictive value (67% vs 92%) significantly improved with the addition of ADC values in the evaluation of patients with type B or C tumors. A persistent or flat TIC pattern on dynamic contrast-enhanced MR images indicates benign disease, but there is added value from including the ADC value in the evaluation of tumors that show a plateau or washout TIC pattern.