Malignant Pleural Disease: Diagnosis by Using Diffusion-weighted and Dynamic Contrast-enhanced MR Imaging—Initial Experience

To compare the diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) imaging with that of dynamic contrast material-enhanced (DCE) MR imaging in evaluating the depth of myometrial invasion and overall stage in patients with endometrial cancer. The institutional review board approved this retrospective study; patient consent was not required. From May 2008 to February 2010, 48 women with endometrial cancer underwent preoperative MR imaging, including T1- and T2-weighted imaging, DW MR imaging (b=0 and 800 sec/mm2) and DCE MR imaging. Two radiologists independently interpreted the depth of myometrial invasion, overall stage, and presence of pitfalls associated with inaccurate assessment of myometrial invasion at T1- and T2-weighted imaging, DW MR imaging, and DCE MR imaging. Myometrial invasion and overall stage were compared by using the McNemar test, and κ statistics were used for reader agreement. For assessing the depth of myometrial invasion, diagnostic accuracy, sensitivity, and specificity, respectively, were as follows: DW MR imaging-reader 1, 90%, 84%, and 100%; reader 2, 85%, 84%, and 88%; DCE MR imaging-reader 1, 71%, 61%, and 88%; reader 2, 79%, 77%, and 82%. The improvement in diagnostic accuracy for reader 1 was significant (P=.035). For myometrial invasion, κ values were 0.75 with DW MR imaging and 0.26 with DCE MR imaging. There was no association between inaccurate assessment of myometrial invasion and standard pitfalls with DW MR imaging. Readers 1 and 2 correctly staged more patients by using DW MR imaging (39 and 38 patients, respectively) than by using DCE MR imaging (29 and 30 patients, respectively) (P<.05). For overall stage, κ values were 0.74 with DW MR imaging and 0.22 with DCE MR imaging. DW MR imaging has superior diagnostic accuracy in the assessment of myometrial invasion and significantly higher staging accuracy compared with DCE MR imaging.

Purpose To evaluate the association between dynamic contrast material-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance (MR) imaging with pathologic complete response after preoperative combined chemotherapy and radiation therapy for cervical carcinoma and evaluate the risk of local recurrence. Materials and Methods The institutional ethics committee approved the study and waived the requirement to obtain informed consent. The study comprised 52 patients with locally advanced carcinoma, treated first with combined chemotherapy and radiation therapy, who underwent MR imaging before final surgery between June 2011 and July 2015. Three radiologists evaluated conventional, DW, and DCE MR images to identify a complete response. The standard of reference was surgical-pathologic findings. Results An initial increase in signal intensity on DCE MR images that was greater in the cervical lesion than in the myometrium was defined as time-signal intensity curve type B and showed a significant association with incomplete response (P = .0004). DCE MR imaging parameters (ie, maximum slope enhancement, area under the gadolinium concentration-time curve during the first 90 seconds after gadolinium injection [AUGC90], and volume transfer constant [Ktrans]) and a low signal intensity on apparent diffusion coefficient (ADC) maps were significantly associated with an incomplete response (P = .027, P = .041, P = .037, and P = .032, respectively). A mean ADC of 0.0014 m2/sec or less (hazard ratio [HR] = 8.3), low ADC signal intensity (HR = 7.3), high signal intensity at DW imaging (HR = 7.1), and time-signal intensity curve type B (HR = 4.3) were associated with earlier recurrence (P < .05). Excellent agreement between readers was found for time-signal intensity curve analysis (κ > 0.9) and the following parameters: AUGC90, Ktrans, and maximum slope enhancement (intraclass correlation coefficient, >0.9). Conclusion DCE MR imaging parameters, especially the time-signal intensity curve, and DW imaging are associated with complete response and incomplete response and could potentially help oncologists with management decisions. Moreover, DCE and DW MR imaging could help oncologists accentuate the follow-up for patients with a high risk of local recurrence to assess for recurrence. © RSNA, 2017 Online supplemental material is available for this article.

To compare diagnostic accuracy of T2-weighted magnetic resonance (MR) imaging with that of multiparametric (MP) MR imaging combining T2-weighted imaging with diffusion-weighted (DW) MR imaging, dynamic contrast material-enhanced (DCE) MR imaging, or both in the detection of locally recurrent prostate cancer (PCa) after radiation therapy (RT). This retrospective HIPAA-compliant study was approved by the institutional review board; informed consent was waived. Fifty-three men (median age, 70 years) suspected of having post-RT recurrence of PCa underwent MP MR imaging, including DW and DCE sequences, within 6 months after biopsy. Two readers independently evaluated the likelihood of PCa with a five-point scale for T2-weighted imaging alone, T2-weighted imaging with DW imaging, T2-weighted imaging with DCE imaging, and T2-weighted imaging with DW and DCE imaging, with at least a 4-week interval between evaluations. Areas under the receiver operating characteristic curve (AUC) were calculated. Interreader agreement was assessed, and quantitative parameters (apparent diffusion coefficient [ADC], volume transfer constant [K(trans)], and rate constant [k(ep)]) were assessed at sextant- and patient-based levels with generalized estimating equations and the Wilcoxon rank sum test, respectively. At biopsy, recurrence was present in 35 (66%) of 53 patients. In detection of recurrent PCa, T2-weighted imaging with DW imaging yielded higher AUCs (reader 1, 0.79-0.86; reader 2, 0.75-0.81) than T2-weighted imaging alone (reader 1, 0.63-0.67; reader 2, 0.46-0.49 [P ≤ .014 for all]). DCE sequences did not contribute significant incremental value to T2-weighted imaging with DW imaging (reader 1, P > .99; reader 2, P = .35). Interreader agreement was higher for combinations of MP MR imaging than for T2-weighted imaging alone (κ = 0.34-0.63 vs κ = 0.17-0.20). Medians of quantitative parameters differed significantly (P < .0001 to P = .0233) between benign tissue and PCa (ADC, 1.64 × 10(-3) mm(2)/sec vs 1.13 × 10(-3) mm(2)/sec; K(trans), 0.16 min(-1) vs 0.33 min(-1); k(ep), 0.36 min(-1) vs 0.62 min(-1)). MP MR imaging has greater accuracy in the detection of recurrent PCa after RT than T2-weighted imaging alone, with no additional benefit if DCE is added to T2-weighted imaging and DW imaging.

To develop a model incorporating dynamic contrast material-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance (MR) imaging features to differentiate high-nuclear-grade (HNG) from non-HNG ductal carcinoma in situ (DCIS) in vivo. This HIPAA-compliant study was approved by the institutional review board and requirement for informed consent was waived. A total of 55 pure DCIS lesions (19 HNG, 36 non-HNG) in 52 women who underwent breast MR imaging at 1.5 T with both DCE and DW imaging (b = 0 and 600 sec/mm(2)) were retrospectively reviewed. The following lesion characteristics were recorded or measured: DCE morphology, DCE maximum lesion size, peak initial enhancement at 90 seconds, worst-curve delayed enhancement kinetics, apparent diffusion coefficient (ADC), contrast-to-noise ratio (CNR) at DW imaging with b values of 0 and 600 sec/mm(2), and T2 signal effects (measured with CNR at b = 0 sec/mm(2)). Univariate and stepwise multivariate logistic regression modeling was performed to identify MR imaging features that optimally discriminated HNG from non-HNG DCIS. Discriminative abilities of models were compared by using the area under the receiver operating characteristic curve (AUC). HNG lesions exhibited larger mean maximum lesion size (P = .02) and lower mean CNR for images with b value of 600 sec/mm(2) (P = .004), allowing discrimination of HNG from non-HNG DCIS (AUC = 0.71 for maximum lesion size, AUC = 0.70 for CNR at b = 600 sec/mm(2)). Differences in CNR for images with b value of 0 sec/mm(2) (P = .025) without corresponding differences in ADC values were observed between HNG and non-HNG lesions. Peak initial enhancement was the only kinetic variable to approach significance (P = .05). No differences in lesion morphology (P = .11) or worst-curve delayed enhancement kinetics (P = .97) were observed. A multivariate model combining CNR for images with b value of 600 sec/mm(2) and maximum lesion size most significantly discriminated HNG from non-HNG (AUC = 0.81). The preliminary findings suggest that DCE and DW MR imaging features may aid in identifying patients with high-risk DCIS. Further study may yield a model combining MR characteristics with histopathologic data to facilitate lesion-specific targeted therapies. © RSNA, 2012.

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.

To investigate diffusion-weighted (DW) magnetic resonance (MR) imaging for differentiating borderline from malignant epithelial tumours of the ovary. This retrospective study included 60 borderline epithelial ovarian tumours (BEOTs) in 48 patients and 65 malignant epithelial ovarian tumours (MEOTs) in 54 patients. DW imaging as well as conventional MR imaging was performed. Signal intensity on DW imaging was assessed and apparent diffusion coefficient (ADC) value was measured. The results were correlated with histopathology and cell density. The majority of MEOTs showed high signal intensity on DW imaging, whereas most BEOTs showed low or moderate signal intensity (P = 0.000). The mean ADC value of the solid components in BEOTs (1.562 ± 0.346 × 10(-3) mm(2)/s) was significantly higher than in MEOTs (0.841 ± 0.209 × 10(-3) mm(2)/s). A threshold value of 1.039 × 10(-3) mm(2)/s permitted the distinction with a sensitivity of 97.0%, a specificity of 92.2% and an accuracy of 96.4%. There was an inverse correlation between ADC value and cell density (r = -0.609; P = 0.0000) which was significantly lower in BEOTs than in MEOTs. DW imaging is useful for differentiating borderline from malignant epithelial tumours of the ovary. DW MR imaging is useful for differentiating BEOTs from MEOTs. Patients with BEOTs are treated differently from patients with MEOTs. Conservative fertility-sparing laparoscopic surgery can be performed in patients with BEOTs. BEOTs often affect young women of childbearing age.

To establish the supplemental value of diffusion-weighted (DW) magnetic resonance (MR) imaging beyond conventional MR to predict clinical outcome after neonatal hypoxic ischemia (HI) at 2 years of age. Forty-six infants with neonatal HI were enrolled in this prospective study, after approval by the local ethical committee and informed consent of the parents. Neonatal MR imaging ranged from 1 to 45 days after birth. Apparent diffusion coefficient (ADC) was measured in 14 brain regions. DW and conventional images were qualitatively scored for abnormalities, resulting in cumulative scores and patterns of damage. Surviving infants were scored for motor outcome at the age of 2 years, and outcome was classified as poor if the motor score was less than 70 or in case of death. Analyses were performed for the whole group, with additional analyses for the early (0-4 days after birth) and late (>4 days after birth) imaging groups. Twenty-five infants had a good outcome and 21 had a poor outcome. Only in the early imaging group, the infants with poor outcome had significantly lowered ADC values in several brain areas, with the posterior limb of the internal capsule being the most predictive (Wald score = 5.7; P = .017). Cumulative scores of DW imaging were the best predictor of poor motor outcome at the age of 2 years (Wald score = 7.2, P < .01). The basal ganglia and central cortex and the diffuse pattern of brain damage were highly associated with poor outcome (Fisher exact test = 29.8; P < .001). In neonatal HI, DW imaging is a useful additional MR technique to predict the motor outcome at 2 years. Local ADC values had a limited value. Recognition of the patterns of brain damage with DW and conventional MR imaging can be used as a diagnostic tool in neonatal HI.

To evaluate the added value of diffusion-weighted magnetic resonance (MR) imaging in diagnostic performance of conventional MR imaging for diagnosis of ampullary carcinoma. This retrospective study was institutional review board approved, and informed consent was waived. Twenty-three patients with malignant ampullary obstruction and 39 patients with benign ampullary obstruction were included. Qualitative (signal intensity and enhancement pattern) and quantitative (apparent diffusion coefficient [ADC]) analyses were conducted for visible or expected locations of duodenal papillae. Two observers independently reviewed conventional MR images and subsequently reviewed combined conventional and diffusion-weighted MR images. A five-point scale for likelihood of ampullary carcinoma was used. Fisher exact test and Mann-Whitney U test were used for comparing groups, and diagnostic performance (receiver operating characteristic [ROC] curve analysis), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated. Visible or expected duodenal papillae in benign group showed isointensity (27-38 of 39, 69%-97%) and similar enhancement pattern (27 of 39, 69%) to that of normal duodenal wall more frequently than in malignant group (seven to 18 of 23 [30%-78%] and three of 23 [13%], respectively) on conventional MR images (P < .05). On diffusion-weighted images, 21 of 23 (91%) ampullary carcinomas showed hyperintensity, whereas all benign cases showed isointensity compared with normal duodenal wall (P < .001). Mean ADC of ampullary carcinomas (1.23 × 10(-3) mm(2)/sec) was significantly lower than that of benign group (1.69 × 10(-3) mm(2)/sec) (P < .001). Diagnostic performance (area under ROC curve [Az]) of both observers improved significantly after additional review of diffusion-weighted images; Az improved from 0.923 to 0.992 (P = .029) for observer 1 and from 0.910 to 0.992 (P = .025) for observer 2. In addition, diagnostic accuracy, sensitivity, specificity, PPV, and NPV of combined conventional and diffusion-weighted MR images were higher than those of conventional MR images alone. Addition of diffusion-weighted imaging to conventional MR imaging improves detection of ampullary carcinoma when compared with conventional MR imaging alone.

Objective To study the effect of diffusion-weighted magnetic resonance imaging (DW-MRI) in the differential diagnosis of hydronephrosis and pyonephrosis. Methods From March 2015 to October 2017, 50 patients with renal stone and highly suspected infectious hydronephrosis underwent renal DW-MRI, and clinical materials were collected and analyzed retrospectively. Seventeen male and 33 female patients were enrolled with a mean age of (49.40±10.51) years. The median maximum diameter of renal stone was 30.30 (17.38, 56.01) mm and hydronephrosis was 46.39 (34.33, 56.55) mm. No pyonephrosis was diagnosed by preoperative ultrasound or CT, while 29 cases of hydronephrosis and 21 cases of pyonephrosis were reported by preoperative DW-MRI. Final diagnoses of hydronephrosis and pyonephrosis were made according to whether the pelvic urine drainage was purulent or not during the surgery. DW-MRI reports and characteristics of DW images were analyzed retrospectively. Apparent diffusion coefficient (ADC) was calculated and ADC map constructed, which was compared between the two groups. Receiver operating characteristic curve (ROC) was drawn to analyze the area under curve (AUC) and the optimal cutoff of ADC value, with sensitivity and specificity. Results Thirty-three patients of hydronephrosis and 17 pyonephrosis were confirmed intraoperatively. The overall accuracy of diagnosis using DW-MRI was 84.00% (42/50), with sensitivity of 88.24% (15/17) and specificity of 81.82% (27/33). Among 30 patients who underwent CT scan in our hospital, mean CT value of 18 hydronephrosis was (7.03±3.26) HU and that of 12 pyonephrosis was (8.67±3.52) HU, with no statistical significance (P>0.05). On DW image, when b≥500 s/mm2, hydronephrosis signal intensity was lowered apparently, whereas pyonephrosis signal intensity was intensified. On ADC map, hydronephrosis appeared as hyperintensity, whereas pyonephrosis appeared as hypointensity. The mean ADC value of pyonephrosis group was lower than hydronephrosis group [(1.53±0. 58)×10-3 mm2/s vs. (2.86±0.56)×10-3 mm2/s, P<0.01]. ROC analysis revealed that AUC=0.92(95%CI 0.80-0.98), and the cut-off value of ADC for pyonephrosis diagnosis was 1.39×10-3 mm2/s, of which the sensitivity and specificity was 94.12% and 84.85% respectively. Conclusions Signal of pyonephrosis was enhanced on DW image, while decreased on ADC image. The ADC value of pyonephrosis was much lower than that of hydronephrosis, with which the differential diagnosis between pyonephrosis and hydronephrosis could be made efficiently. Key words: Hydronephrosis; Pyonephrosis; Urosepsis; Diffusion-weighted imaging; Apparent diffusion coefficient

Gastrointestinal stromal tumours: Correlation of modified NIH risk stratification with diffusion-weighted MR imaging as an imaging biomarker

To determine whether changes in apparent diffusion coefficients (ADCs) of rectal carcinoma obtained 1 week after the beginning of chemotherapy and radiation therapy (CRT) correlate with tumor histopathologic downstaging after preoperative CRT. This prospective study was approved by an institutional review board; informed consent was obtained from all patients. Thirty-seven patients (mean age, 54.7 years; 13 women, 24 men) with primary rectal carcinoma who were undergoing preoperative CRT were recruited for the study. Diffusion-weighted (DW) magnetic resonance (MR) imaging was performed with a 1.5-T MR imager in all patients before therapy, at the end of the 1st and 2nd week of therapy, and before surgery. Tumor ADCs were calculated. Linear mixed-effects modeling was applied to analyze change in ADCs and volumes following treatment. Patients were assigned to the tumor downstaged group (n = 17) or the tumor nondownstaged group (n = 20) on the basis of histopathologic examination results following surgery. Before CRT, the mean tumor ADC in the downstaged group was lower than that in the nondownstaged group (1.07 x 10(-3) mm(2)/sec +/- 0.13 [standard deviation] vs 1.19 x 10(-3) mm(2)/sec +/- 0.15, F = 6.91, P = .013). At the end of the 1st week of CRT, the mean tumor ADC increased significantly from 1.07 x 10(-3) mm(2)/sec +/- 0.13 to 1.32 x 10(-3) mm(2)/sec +/- 0.16 (F = 37.63, P <.001) in the downstaged group, but there was no significant ADC increase in the nondownstaged group (F = 1.18, P = .291). The mean percentage of tumor ADC change in the downstaged group was significantly higher than that in the nondownstaged group at each time point (F = 18.39, P < .001). Early increase of mean tumor ADC and low pretherapy mean ADC in rectal carcinoma correlate with good response to CRT. DW MR imaging is a promising noninvasive technique for helping predict and monitor early therapeutic response in patients with rectal carcinoma who are undergoing CRT.

Evaluation of solid lesions affecting masticator space with diffusion-weighted MR imaging

Is diffusion-weighted magnetic resonance imaging superior to positron emission tomography with fludeoxyglucose F 18 in imaging non–small cell lung cancer?

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

45 - Prostate Cancer: Diffusion-Weighted Imaging