Volumetric MRI assessment of perirenal hematoma following biopsy of native and transplanted kidneys.

Abstract: BACKGROUND AND AIM: Diffusion-weighted imaging (DWI) has now become an integral component of the musculoskeletal tumor protocol magnetic resonance imaging (MRI). Although a conventional radiograph is still considered the primary modality, MRI is invariably performed for further characterization of the tumor. Being a fast noncontrast sequence and considering its role in detecting highly cellular lesions, DWI can prove as a helpful tool for those who have inconclusive radiographic or conventional MRI diagnosis. The aim of this study was to determine the role of DWI and apparent diffusion coefficient (ADC) value in the evaluation and differentiation of malignant and benign bones and soft-tissue neoplasms. We also derived a cutoff ADC value to differentiate the above two. MATERIALS AND METHODS: This is an IRB-approved retrospective study of 85 patients with histopathologically proven bone (n = 61, 47 malignant and 14 benign) or soft-tissue (n = 24, 21 malignant and 3 benign) neoplasms. Conventional MR features such as size, margins, T1/T2 signal intensity, cortical breach/bone expansion/medullary involvement, and neurovascular bundle involvement were assessed. DWI analysis was done by a blinded radiologist having MRI reporting experience of 3 years by placing three regions of interest on solid (nonnecrotic) components, and mean ADC values were derived for each neoplasm. These were confirmed by another senior radiologist with an experience of more than 15 years with MRI. Histopathological diagnosis was considered a gold standard. Mean ADC values of the benign and malignant groups were compared statistically. Sensitivity, specificity, and diagnostic accuracy were obtained. Receiver operating characteristic (ROC) curves were generated, and a cutoff ADC value was derived to differentiate benign and malignant tumors. RESULTS: True visual diffusion restriction was confirmed among 34/47 malignant bone tumors on b-800 DW images, whereas 10/14 benign bone tumors showed facilitated diffusion. Similarly, visual restriction was seen among 20/21 malignant soft tumors, whereas 2 out of 3 benign soft-tissue tumors showed visually facilitated diffusion. Statistically, a significant difference was noted between the mean ADC value of malignant (1.20 ± 0.68 × 10−3 mm2/s) and benign bone tumors (1.57 ± 0.69 × 10−3 mm2/s) (P = 0.04). Relatively high ADC values were noted in the chondrosarcoma group (n = 19), with 11/19 chondrosarcomas showing facilitated diffusion with a mean ADC value of 1.73 × 10−3 mm2/s. Similarly, among benign bone tumors, contrary to expectation, relatively lower ADC values were noted in giant cell tumors (n = 4) with a mean ADC value of 1.18 × 10−3 mm2/s. For soft-tissue tumors, a lower mean ADC value was noted for the malignant (0.85 ± 0.26 × 10−3 mm2/s) versus the benign group (1.33 ± 0.20 × 10−3 mm2/s) (P = 0.006). For bone neoplasms, a cutoff mean ADC value of 1.1 × 10−3 mm2/s was derived from the ROC curve with sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 72.3%, 71.4%, 89.5%, and 43.5%, respectively. For the soft-tissue group, a cutoff mean ADC value of 1.0 × 10−3 mm2/s was achieved with sensitivity, specificity, PPV, and NPV of 100%, 85.7%, 50%, and 100%, respectively. CONCLUSIONS: In addition to conventional MR, DWI with ADC analysis is a powerful tool in musculoskeletal tumor evaluation and an ADC cutoff value may help differentiate benign from malignant neoplasms. In chondroid malignancies, relatively high ADC values may be seen and DWI analysis may not be as useful.

Objective To explore the role of apparent diffusion coefficient (ADC) value of diffusion-weighted imaging (DWI) in the differentiation between benign and malignant bone tumors. Methods Echo planar imaging DWI was performed in 18 patients with benign tumor or tumorous lesion and 26 patients with malignant tumor of bone. Three b-values (0, 500 and 1000 s/mm2) were applied. The lowest, highest, and whole ADC values were measured for each lesion, respectively. Results The lowest ADC values of benign bone tumor[ mean( 1.28±0. 49) ×10-3mm2/s ] were significantly higher than that of malignant tumor [ mean ( 0. 92±0. 35 )×10-3mm2/s, t = 2. 839, P 0. 05 ]. Excluding cases of bone cyst and aneurismal bone cyst, the lowest, highest, and whole ADC values of benign bone tumor was (1.11± 0. 31 )×10-3mm2/s, ( 1.88±0. 49)×10-3mm2/s, and( 1.45±0. 35 )×10-3mm2/s, respectively. There was no significant difference for the lowest, highest, or whole ADC values between benign and malignant bone tumor (t = 1. 728, 0. 964, and 2. 012, respectively, P > 0. 05). Conclusion ADC value is useless for the differentiation between benign and malignant bone tumors. Key words: Bone neoplasm; Diffusion-weighted imaging; Magnetic resonance imaging

The Utility of Mean Apparent Diffusion Coefficient Value in Patients with Prostate Cancer Treated with Definitive Radiotherapy

The prognostic value of mean apparent diffusion coefficient measured with diffusion-weighted magnetic resonance image in patients with prostate cancer treated with definitive radiotherapy

Multicenter analysis of clinical and MRI characteristics associated with detecting clinically significant prostate cancer in PI-RADS (v2.0) category 3 lesions

Canine intracranial meningiomas can be graded based on histological classification as benign (grade I), atypical (grade II), and anaplastic or malignant (grade III). In people, grade II/III meningiomas behave more aggressively, have a higher potential for recurrence after surgical resection, and have lower apparent diffusion coefficient (ADC) values with diffusion weighted imaging (DWI). In this retrospective analytical cross-sectional study, 42 dogs had ADC values quantified in an attempt to differentiate tumor histologic grade. Our hypothesis was that ADC values would be significantly lower in grade II and III versus grade I meningiomas in dogs. On each ADC image, a polygonal region of interest (ROI) was hand-drawn along the lesion's periphery, excluding fluid-filled and hemorrhagic regions. Mean ADC value (ADCmean ) and minimum ADC value (ADCmin ) were calculated. Additionally, two smaller, ovoid ROI were drawn within the lesion with mean ADC calculated (ADCmean sR and ADCmin sR ). Normalized ADC values using white matter were also calculated (ADCn and ADCn sR ). Grades of each tumor were assigned based on histopathology review. Association between ADC parameters and histological grade was tested by means of two-sample t-tests. There were 14 grade I (33.3%), 25 grade II (59.5%), and three grade III (7.2%) meningiomas. ADCmean sR and ADCmin sR were significantly lower when comparing grade II/III to grade I (P<.05). Grade II tumors had significantly lower ADCmean , ADCmean sR , ADCmin sR , ADCn , and ADCn sR than grade I meningiomas. This preliminary study supports the potential of ADC values to help predict the histological grade of intracranial meningiomas in dogs.

Association of quantifiable prostate MRI parameters with any and large cribriform pattern in prostate cancer patients undergoing radical prostatectomy

The impact of the apparent diffusion coefficient for the early prediction of the treatment response after definitive radiotherapy in prostate cancer patients

The purpose of this study was to investigate the relationship between Ki-67 proliferation indexes and apparent diffusion coefficient (ADC) values of low-grade and atypical/anaplastic (high-grade) meningiomas. Pre-operative diffusion-weighted imaging and histopathological evaluation of 44 patients with meningiomas were performed retrospectively. Regions of interest (ROIs) were manually drawn on the ADC images. In total six ROI measurements were taken in three consecutive slices, and the average of the mean ADC value was used. The relationship between the ADC and Ki-67 values was investigated, and the ADC values of the low-grade and high-grade meningiomas were compared. 31 (70%) patients had low-grade the meningiomas. 10 (23%) patients had atypical and 3 (7%) had anaplastic meningiomas. ADC values of the low-grade and high-grade meningiomas were 0.81 ± 0.12 × 10(-3) and 0.66 ± 0.08 × 10(-3) mm(2) s(-1), respectively. Ki-67 proliferation indexes were 2.19% ± 1.14% for low-grade and 11.20% ± 9.80% for high-grade meningiomas. A statistically significant negative correlation between Ki-67 proliferation index and ADC values of the low-grade and high-grade meningiomas was detected (r(2) = 0.326, p < 0.001). High-grade meningiomas had lower ADC values than that of low-grade meningiomas. There was statistically significant difference between the ADC values of the low-grade and high-grade meningiomas (p < 0.001). Our data provide an inverse correlation between the ADC and Ki-67 proliferation index values of meningiomas. ADC values can be used for histopathological characterization of the meningiomas and pre-surgical planning. The purpose of this study was to investigate the relationship between Ki-67 proliferation indexes and ADC values of low-grade and atypical/anaplastic (high-grade) meningiomas. In addition, we compared the ADC and Ki-67 proliferative index values of the low-grade and atypical/anaplastic (high-grade) meningiomas. We concluded that there was an inverse correlation between the ADC and Ki-67 proliferation index values in meningiomas, and we have found statistically significant difference between the ADC values of the low-grade and high-grade meningiomas. ADC values can be used for histopathological characterization of the meningiomas and pre-surgical planning.

Evaluating transcatheter arterial chemoembolization for primary hepatic cancer by magnetic resonance diffusion-weighted imaging

Objective To determine the magnetic resonance diffusion weighted imaging (DWI) images of patients with endometrial stromal sarcoma (ESS) and to evaluate the related biological behavior. Methods Eighty ESS patients admitted to our hospital (January 2016 to December 2018) were included as the ESS group, and a contemporary cohort of 75 patients with uterine fibroids (UM) was included as the UM group. Conventional magnetic resonance imaging and DWI examination were performed in both groups, and the DWI apparent diffusion coefficient (ADC) values were calculated. According to ADC values, 80 ESS patients were divided into two subgroups: high ADC value group (n=40) and low ADC value group (n=40) . After the relevant examinations were completed, all patients received surgical treatment. The pathological specimens were taken to examine the expression levels of proliferating genes (Survivin, CyclinD1, Sp1 and Rb) and estrogen and progesterone receptors (SULT1E1, PRA, PRB, ERα and ERβ) . The ADC values in the ESS group and UM group were compared. The expression levels of proliferating genes and estrogen and progesterone receptors in the ESS group and UM group, and high ADC group and low ADC group were compared. Results (1) ADC value: The ADC value in the ESS group was lower than that in the UM group (P<0.05) . (2) Proliferating genes: The expression levels of Survivin, CyclinD1, Sp1 and Rb genes in the ESS group were higher than those in the UM group (P<0.05) . The expression levels of Survivin, CyclinD1, Sp1 and Rb genes in the high ADC group were lower than those in the low ADC group (P<0.05) . (3) Estrogen and progesterone receptors: The expression level of SULT1E1 receptor in the ESS group was lower than that in the UM group, whereas the expression levels of PRA, PRB, ERα and ERβ receptors were higher than those in the UM group (P<0.05) . The expression level of SULT1E1 receptor in the high ADC group was higher than that in the low ADC group, whereas the expression levels of PRA, PRB, ERα and ERβ receptors were lower than those in the low ADC group (P<0.05) . Conclusion DWI may differentiate benign and malignant lesions of uterus by ADC value. With the increase of malignant ESS malignancy, the ADC value shows a downward trend. Therefore, DWI examination favors accurate evaluation of the degree of ESS malignancy before surgery, so as to guide and develop individualized treatment and intervention protocol in the clinical settings. Key words: Endometrial stromal sarcoma; Magnetic resonance diffusion weighted imaging; Biological behavior; Proliferation gene expression; Estrogen and progesterone receptor expression

Diffusion Weighted Imaging: What Are We Really Seeing?

Background and purpose: Accurate imaging diagnosis before surgery is fundamental to determine whether a tumor is benign or malignant. Diagnosis only from structural MRI is not specific. However, the diffusivity of the benign and malignant lesion is different and could be measured by ADC. The Apparent Diffusion Coefficient (ADC) values are calculated automatically by application software and displayed as a parametric map that reflects the degree of diffusion of water molecules through different tissues. The purpose of this study was to analyze the correlation between Diffusion-Weighted Magnetic Resonance Imaging (DWI) and Apparent Diffusion Coefficient (ADC) values with histopathology grading of brain tumors. Material and methods: Pathology reports of intracranial tumor material were correlated with diffusivity of the tumor, and the ADC values, performed within 2 years of post-operative histopathology study. A freehand closed ROI out-lined the whole visible tumor on the most representative slice of ADC maps defined as the slice with the maximum diameter of the solid neoplastic component. ADC values were taken from 2 averages of 2 ROIs. Spearman Correlation test was used to assess the correlation between ADC values with the malignancy grading of the tumor. Result: Low-grade malignant tumors show facilitated diffusion with high ADC values, and high-grade malignant tumors show restricted diffusion with low ADC values. The mean ADC value of Grade I tumor is 1.0799 ± 0.2356 x 10−3 mm2/sec and the mean ADC value of Grade IV tumor is 0.6798 ± 0.23729 x 10−3 mm2/sec. The Spearman correlation test between ADC value and histopathology result shown r = -0.536 and p=0.000 and the test result for ADC value and DWI shown r=-0.706 and p=0.000 (Sig. 0.05). Conclusion: There was strong correlation between DWI and ADC values with histopathology grading of intracranial tumors.

Delineation of Spatially-Varied High-Risk GTV in Pancreatic Adenocarcinoma Using MRI-ADC Maps

The aim of this study was to identify whether diffusion-weighted magnetic resonance imaging (DW-MRI) can predict the malignant behavior of preoperative well-differentiated pancreatic neuroendocrine tumors (PanNETs). Forty patients with PanNETs who underwent pancreatectomy were enrolled in this study. The apparent diffusion coefficient (ADC) values were measured. Clinicopathological factors were compared in patients with high ADC and low ADC values and in patients with and without lymph node metastasis (LNM). The low ADC group was significantly associated with higher Ki-67 index, higher mitotic count, larger tumor size, higher rate of LNM, and venous invasion. In patients with low ADC values, the incidence of LNMs was 33.3%. In patients with high ADC values, there were no patients with LNM being 0%. A significant negative correlation was found between the mean ADC values and the Ki-67 index and between the mean ADC values and the mitotic count. In multivariate analysis, neural invasion and mean ADC values ≤ 1458 were independent predictors of LNM. ADC values obtained using DW-MRI in the preoperative assessment of patients with PanNETs might be a useful predictor of malignant potential, especially LNM.