Improving reader accuracy and specificity with the addition of hybrid multidimensional-MRI to multiparametric-MRI in diagnosing clinically significant prostate cancers.

PURPOSE: Compare reader performance when adding the Hybrid Multidimensional-MRI (HM-MRI) map to multiparametric MRI (mpMRI+HM-MRI) versus mpMRI alone and inter-reader agreement in diagnosing clinically significant prostate cancers (CSPCa). METHODS: All 61 patients who underwent mpMRI (T2-, diffusion-weighted (DWI), and contrast-enhanced scans) and HM-MRI (with multiple TE/b-value combinations) before prostatectomy or MRI-fused-transrectal ultrasound-guided biopsy between August, 2012 and February, 2020, were retrospectively analyzed. Two experienced readers (R1, R2) and two less-experienced readers (less than 6-year MRI prostate experience) (R3, R4) interpreted mpMRI without/with HM-MRI in the same sitting. Readers recorded the PI-RADS 3-5 score, lesion location, and change in score after adding HM-MRI. Each radiologist's mpMRI+HM-MRI and mpMRI performance measures (AUC, sensitivity, specificity, PPV, NPV, and accuracy) based on pathology, and Fleiss' kappa inter-reader agreement was calculated and compared. RESULTS: Per-sextant R3 and R4 mpMRI+HM-MRI accuracy (82% 81% vs. 77%, 71%; p=.006, <.001) and specificity (89%, 88% vs. 84%, 75%; p=.009, <.001) were higher than with mpMRI. Per-patient R4 mpMRI+HM-MRI specificity improved (48% from 7%; p<.001). R1 and R2 mpMRI+HM-MRI specificity per-sextant (80%, 93% vs. 81%, 93%; p=.51,>.99) and per-patient (37%, 41% vs. 48%, 37%; p=.16, .57) remained similar to mpMRI. R1 and R2 per-patient AUC with mpMRI+HM-MRI (0.63, 0.64 vs. 0.67, 0.61; p=.33, .36) remained similar to mpMRI, but R3 and R4 mpMRI+HM-MRI AUC (0.73, 0.62) approached R1 and R2 AUC. Per-patient inter-reader agreement, mpMRI+HM-MRI Fleiss Kappa, was higher than mpMRI (0.36 [95% CI 0.26, 0.46] vs. 0.17 [95% CI 0.07, 0.27]); p=.009). CONCLUSION: Adding HM-MRI to mpMRI (mpMRI+HM-MRI) improved specificity and accuracy for less-experienced readers, improving overall inter-reader agreement.

An Interactive App with Multi-parametric MRI - Whole-Mount Histology Correlation for Enhanced Prostate MRI Training of Radiology Residents.

RATIONALE AND OBJECTIVES: To validate the educational value of a newly created learning application in enhancing prostate MRI training of radiologists for detecting prostate cancer using an observer study. MATERIALS AND METHODS: An interactive learning app, LearnRadiology, was developed using a web-based framework to display multi-parametric prostate MRI images with whole-mount histology for 20 cases curated for unique pathology and teaching points. Twenty new prostate MRI cases, different from the ones used in the web app, were uploaded on 3D Slicer. Three radiologists (R1: radiologist; R2, R3: residents) blinded to pathology results were asked to mark areas suspected of cancer and provide a confidence score (1-5, with 5 being high confidence level). Then after a minimum memory washout period of 1 month, the same radiologists used the learning app and then repeated the same observer study. The diagnostic performance for detecting cancers before and after accessing the learning app was measured by correlating MRI with whole-mount pathology by an independent reviewer. RESULTS: The 20 subjects included in the observer study had 39 cancer lesions (13 Gleason 3 + 3, 17 Gleason 3 + 4, 7 Gleason 4 + 3, and 2 Gleason 4 + 5 lesions). The sensitivity (R1: 54% â†’ 64%, P = 0.08; R2: 44% â†’ 59%, P = 0.03; R3: 62% â†’ 72%, P = 0.04) and positive predictive value (R1: 68% â†’ 76%, P = 0.23; R2: 52% â†’ 79%, P = 0.01; R3: 48% â†’ 65%, P = 0.04) for all 3 radiologists improved after using the teaching app. The confidence score for true positive cancer lesion also improved significantly (R1: 4.0 ± 1.0 â†’ 4.3 ± 0.8; R2: 3.1 ± 0.8 â†’ 4.0 ± 1.1; R3: 2.8 ± 1.2 â†’ 4.1 ± 1.1; P < 0.05). CONCLUSION: The web-based and interactive LearnRadiology app learning resource can support medical student and postgraduate education by improving diagnostic performance of trainees for detecting prostate cancer.

Comparing Radiologist Performance in Diagnosing Clinically Significant Prostate Cancer with Multiparametric versus Hybrid Multidimensional MRI.

Background Variability of acquisition and interpretation of prostate multiparametric MRI (mpMRI) persists despite implementation of the Prostate Imaging Reporting and Data System (PI-RADS) version 2.1 due to the range of reader experience and subjectivity of lesion characterization. A quantitative method, hybrid multidimensional MRI (HM-MRI), may introduce objectivity. Purpose To compare performance, interobserver agreement, and interpretation time of radiologists using mpMRI versus HM-MRI to diagnose clinically significant prostate cancer. Materials and Methods In this retrospective analysis, men with prostatectomy or MRI-fused transrectal US biopsy-confirmed prostate cancer underwent mpMRI (triplanar T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging) and HM-MRI (with multiple echo times and b value combinations) from August 2012 to February 2020. Four readers with 1-20 years of experience interpreted mpMRI and HM-MRI examinations independently, with a 4-week washout period between interpretations. PI-RADS score, lesion location, and interpretation time were recorded. mpMRI and HM-MRI interpretation time, interobserver agreement (Cronbach alpha), and performance of area under the receiver operating characteristic curve (AUC) analysis were compared for each radiologist with use of bootstrap analysis. Results Sixty-one men (mean age, 61 years ± 8 [SD]) were evaluated. Per-patient AUC was higher for HM-MRI for reader 4 compared with mpMRI (AUCs for readers 1-4: 0.61, 0.71, 0.59, and 0.64 vs 0.66, 0.60, 0.50, and 0.46; P = .57, .20, .32, and .04, respectively). Per-patient specificity was higher for HM-MRI for readers 2-4 compared with mpMRI (specificity for readers 1-4: 48%, 78%, 48%, and 46% vs 37%, 26%, 0%, and 7%; P = .34, P < .001, P < .001, and P < .001, respectively). Diagnostic performance improved for the reader least experienced with HM-MRI, reader 4 (AUC, 0.64 vs 0.46; P = .04). HM-MRI interobserver agreement (Cronbach alpha = 0.88 [95% CI: 0.82, 0.92]) was higher than that of mpMRI (Cronbach alpha = 0.26 [95% CI: 0.10, 0.52]; α > .60 indicates reliability; P = .03). HM-MRI mean interpretation time (73 seconds ± 43 [SD]) was shorter than that of mpMRI (254 seconds ± 133; P = .03). Conclusion Radiologists had similar or improved diagnostic performance, higher interobserver agreement, and lower interpretation time for clinically significant prostate cancer with hybrid multidimensional MRI than multiparametric MRI. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Turkbey in this issue.

The relationship between inflammation and mean platelet volume in varicocele pathophysiology / Relación entre inflamación y volumen plaquetario medio en la fisiopatología del varicocele

Introduction: The mean platelet volume (MPV) is an extensively employed laboratory indicator related to platelet volume and function in inflammatory circumstances. The aim of this study was to assess the relationship between inflammation and mean platelet volume in varicocele pathophysiology. Methods: We conducted a recent study, which included 131 varicocele subjects and 82 healthy controls. The identification of varicocele was based on the results from both physical examination and color Doppler ultrasound. We analyzed some laboratory markers including haemogram tests in two groups. Results: There were no significant differences in the two groups in terms of baseline characteristics. MPV values were statistically higher in the varicocele group (9.73±0.86fL) than in the control group (9.03±0.70fL) (p<0.001). However, no significant relationship between MPV and varicocele grade was found. Furthermore, the receiver-operating characteristic curve analysis suggested the optimum MPV cut-off value for patients with varicocele as 9.05, with a sensitivity and specificity of 77% and 50%, respectively (p<0.001). Conclusion: MPV can offer information on varicocele pathophysiology. Increased MPV levels in varicocele patients may be associated with inflammation

Introducción: El volumen plaquetario medio (VPM) es un indicador de laboratorio ampliamente empleado en relación con la función plaquetaria y el volumen plaquetario en contextos inflamatorios. El objetivo de este estudio es estudiar la relación entre inflamación y volumen plaquetario medio en la patofisiología del varicocele. Métodos: Se lleva a cabo un estudio en el que se incluyen 131 casos de varicocele y 82 controles sanos. El diagnóstico de varicocele se basa en los hallazgos de la exploración física y los resultados del eco-Doppler color. Se analizan distintos marcadores de laboratorio, incluyendo hemograma, en los 2 grupos. Resultados: No se encuentran diferencias significativas en las características basales de los 2 grupos estudiados. El valor VPM fue más elevado en el grupo de pacientes con varicocele (9,73±0,86fL) en comparación con el grupo control (9,03±0,70fL) (p<0,001). Sin embargo, no se encontraron diferencias significativas entre el VPM y el grado de varicocele. Por otro lado, el análisis de la curva ROC sugiere que el valor de corte óptimo para el VPM para los pacientes con varicocele fue de 9,05 con una sensibilidad y especificidad del 77 y 50%, respectivamente (p>0,001). Conclusión: El VPM puede ofrecer información sobre la fisiopatología del varicocele. Los niveles altos del VPM pueden estar asociados con la inflamación

The relationship between inflammation and mean platelet volume in varicocele pathophysiology.

INTRODUCTION: The mean platelet volume (MPV) is an extensively employed laboratory indicator related to platelet volume and function in inflammatory circumstances. The aim of this study was to assess the relationship between inflammation and mean platelet volume in varicocele pathophysiology. METHODS: We conducted a recent study, which included 131 varicocele subjects and 82 healthy controls. The identification of varicocele was based on the results from both physical examination and color Doppler ultrasound. We analyzed some laboratory markers including haemogram tests in two groups. RESULTS: There were no significant differences in the two groups in terms of baseline characteristics. MPV values were statistically higher in the varicocele group (9.73±0.86fL) than in the control group (9.03±0.70fL) (p<0.001). However, no significant relationship between MPV and varicocele grade was found. Furthermore, the receiver-operating characteristic curve analysis suggested the optimum MPV cut-off value for patients with varicocele as 9.05, with a sensitivity and specificity of 77% and 50%, respectively (p<0.001). CONCLUSION: MPV can offer information on varicocele pathophysiology. Increased MPV levels in varicocele patients may be associated with inflammation.

Measurements of Hepatic Metastasis on MR Imaging:: Assessment of Interobserver and Intersequence Variability.

RATIONALE AND OBJECTIVES: The purpose of the study was to investigate interobserver and intersequence variability in the measurement of hepatic metastasis on magnetic resonance imaging (MRI). MATERIALS AND METHODS: This retrospective study was conducted with an institutional review board-approved waiver of informed consent and was in compliance with the Health Insurance Portability and Accountability Act. We searched medical records at our institution for patients with histologically proven metastases to the liver who had undergone MRI from January 2008 to June 2010. We identified 20 patients with 30 measurable liver lesions. The liver lesions were measured on five different MRI sequences. A presenter radiologist selected and localized all metastatic lesions considered to be measurable according to the Response Evaluation Criteria in Solid Tumors, and these lesions were measured (Eisenhauer et al., 2009) by three radiologists independently. We calculated lesion-wise intraclass correlation coefficients (ICCs) to estimate interobserver and intersequence agreement in lesion diameter measurement. A Bland-Altman plot was used to estimate the limits of agreement between radiologists and MRI sequences. RESULTS: There were 30 metastases, and almost all of which had regular and well-defined margins. Interobserver ICCs were greater than 0.95 for different MRI sequences except for the measurements in apparent diffusion coefficient images. Intersequence ICCs were greater than 0.92. Bland-Altman plots between physicians confirmed that reader measurements were closely tied together, with small differences in means. CONCLUSIONS: MRI can reproducibly measure hepatic metastatic lesions without significant variability among interpreting radiologists or among MRI sequences, and is thus a reliable method for assessing the size of hepatic metastasis.

MRI-based prostate volume-adjusted prostate-specific antigen in the diagnosis of prostate cancer.

PURPOSE: To determine whether prostate-specific antigen (PSA) levels adjusted by prostate and zonal volumes estimated from magnetic resonance imaging (MRI) improve the diagnosis of prostate cancer (PCa) and differentiation between patients who harbor high-Gleason-sum PCa and those without PCa. MATERIALS AND METHODS: This retrospective study was Health Insurance Portability and Accountability Act (HIPAA)-compliant and approved by the Institutional Review Board of participating medical institutions. T2 -weighted MR images were acquired for 61 PCa patients and 100 patients with elevated PSA but without PCa. Computer methods were used to segment prostate and zonal structures and to estimate the total prostate and central-gland (CG) volumes, which were then used to calculate CG volume fraction, PSA density, and PSA density adjusted by CG volume. These quantities were used to differentiate patients with and without PCa. Area under the receiver operating characteristic curve (AUC) was used as the figure of merit. RESULTS: The total prostate and CG volumes, CG volume fraction, and PSA density adjusted by the total prostate and CG volumes were statistically significantly different between patients with PCa and patients without PCa (P ≤ 0.007). AUC values for the total prostate and CG volumes, and PSA density adjusted by CG volume, were 0.68 ± 0.04, 0.68 ± 0.04, and 0.66 ± 0.04, respectively, and were significantly better than that of PSA (P < 0.02), for differentiation of PCa patients from patients without PCa. CONCLUSION: The total prostate and CG volumes estimated from T2 -weighted MR images and PSA density adjusted by these volumes can improve the effectiveness of PSA for the diagnosis of PCa and differentiation of high-Gleason-sum PCa patients from patients without PCa.

Short-term reproducibility of apparent diffusion coefficient estimated from diffusion-weighted MRI of the prostate.

PURPOSE: The purpose of the study is to determine short-term reproducibility of apparent diffusion coefficient (ADC) estimated from diffusion-weighted magnetic resonance (DW-MR) imaging of the prostate. METHODS: Fourteen patients with biopsy-proven prostate cancer were studied under an Institutional Review Board-approved protocol. Each patient underwent two, consecutive and identical DW-MR scans on a 3T system. ADC values were calculated from each scan and a deformable registration was performed to align corresponding images. The prostate and cancerous regions of interest (ROIs) were independently analyzed by two radiologists. The prostate volume was analyzed by sextant. Per-voxel absolute and relative percentage variations in ADC were compared between sextants. Per-voxel and per-ROI variations in ADC were calculated for cancerous ROIs. RESULTS: Per-voxel absolute difference in ADC in the prostate ranged from 0 to 1.60 × 10(-3) mm(2)/s (per-voxel relative difference 0% to 200%, mean 10.5%). Variation in ADC was largest in the posterior apex (0% to 200%, mean 11.6%). Difference in ADC variation between sextants was not statistically significant. Cancer ROIs' per-voxel variation in ADC ranged from 0.001 × 10(-3) to 0.841 × 10(-3) mm(2)/s (0% to 67.4%, mean 11.2%) and per-ROI variation ranged from 0 to 0.463 × 10(-3) mm(2)/s (mean 0.122 × 10(-3) mm(2)/s). CONCLUSIONS: Variation in ADC within the human prostate is reasonably small, and is on the order of 10%.

High-resolution diffusion-weighted imaging of the prostate.

OBJECTIVE: The purpose of this study was to evaluate the effect of increasing the spatial resolution of the prostate DWI protocol on image quality and lesion conspicuity. SUBJECTS AND METHODS: Twenty-nine patients with biopsy-proven prostate cancer undergoing MRI examinations were imaged with two diffusion-weighted imaging (DWI) protocols: current standard clinical protocol (6.7 mm(3) voxels) and a new high-resolution protocol (3.1 mm(3) voxels). Diffusion-weighted images were independently and subjectively scored on lesion conspicuity, internal architecture definition, and overall image quality by two radiologists. Average apparent diffusion coefficient (ADC) values were measured in normal tissue and cancerous lesions on both sequences. Reader scores and ADC and contrast values were compared between the two protocols. Cancer ADC values were correlated with Gleason scores. RESULTS: The signal-to-noise ratio of the new high-resolution DWI protocol was 40% lower than that of the standard protocol. The reader scores were higher by 0.73 (range, 0.29-1.16) grades, or 19% (range, 7-32%), on average, for the new protocol, indicating better image quality. The average ADC values were 8% higher with the new protocol, with ADC contrast values between cancer and normal prostate unchanged. There was marginally significant correlation of cancer ADC values with Gleason scores (p = 0.05, r ≈ -0.36). CONCLUSION: We showed that for DWI of the prostate at 3-7 mm(3) voxel sizes the benefits of higher spatial resolution outweigh the effects of reduced signal-to-noise and contrast-to-noise ratios, potentially improving the sensitivity to small or sparse prostate cancers. Radiologists can consider using higher-spatial-resolution DWI sequences in their practices.

Dynamic contrast-enhanced MR imaging features of the normal central zone of the prostate.

RATIONALE AND OBJECTIVES: Evaluate qualitative dynamic contrast-enhanced magnetic resonance imaging (MRI) characteristics of normal central zone based on recently described central zone MRI features. MATERIALS AND METHODS: Institutional review board-approved, Health Insurance Portability and Accountability Act compliant study, 59 patients with prostate cancer, histopathology proven to not involve central zone or prostate base, underwent endorectal MRI before prostatectomy. Two readers independently reviewed T2-weighted images and apparent diffusion coefficient (ADC) maps identifying normal central zone based on low signal intensity and location. Next, two readers drew bilateral central zone regions of interest on dynamic contrast-enhanced magnetic resonance images in consensus and independently recorded enhancement curve types as type 1 (progressive), type 2 (plateau), and type 3 (wash-out). Identification rates of normal central zone and enhancement curve type were recorded and compared for each reviewer. The institutional review board waiver was approved and granted 05/2010. RESULTS: Central zone identified in 92%-93% of patients on T2-weighted images and 78%-88% on ADC maps without significant difference between identification rates (P = .63 and P = .15 and inter-reader agreement (κ) is 0.64 and 0.29, for T2-weighted images and ADC maps, respectively). All central zones were rated either curve type 1 or curve type 2 by both radiologists. No statistically significant difference between the two radiologists (P = .19) and inter-reader agreement was κ = 0.37. CONCLUSIONS: Normal central zone demonstrates either type 1 (progressive) or type 2 (plateau) enhancement curves on dynamic contrast-enhanced MRI that can be potentially useful to differentiate central zone from prostate cancer that classically demonstrates a type 3 (wash-out) enhancement curve.

Computerized liver volumetry on MRI by using 3D geodesic active contour segmentation.

OBJECTIVE: Our purpose was to develop an accurate automated 3D liver segmentation scheme for measuring liver volumes on MRI. SUBJECTS AND METHODS: Our scheme for MRI liver volumetry consisted of three main stages. First, the preprocessing stage was applied to T1-weighted MRI of the liver in the portal venous phase to reduce noise and produce the boundary-enhanced image. This boundary-enhanced image was used as a speed function for a 3D fast-marching algorithm to generate an initial surface that roughly approximated the shape of the liver. A 3D geodesic-active-contour segmentation algorithm refined the initial surface to precisely determine the liver boundaries. The liver volumes determined by our scheme were compared with those manually traced by a radiologist, used as the reference standard. RESULTS: The two volumetric methods reached excellent agreement (intraclass correlation coefficient, 0.98) without statistical significance (p = 0.42). The average (± SD) accuracy was 99.4% ± 0.14%, and the average Dice overlap coefficient was 93.6% ± 1.7%. The mean processing time for our automated scheme was 1.03 ± 0.13 minutes, whereas that for manual volumetry was 24.0 ± 4.4 minutes (p < 0.001). CONCLUSION: The MRI liver volumetry based on our automated scheme agreed excellently with reference-standard volumetry, and it required substantially less completion time.

Hybrid multidimensional T(2) and diffusion-weighted MRI for prostate cancer detection.

PURPOSE: To study the dependence of apparent diffusion coefficient (ADC) and T2 on echo time (TE) and b-value, respectively, in normal prostate and prostate cancer, using two-dimensional MRI sampling, referred to as "hybrid multidimensional imaging." MATERIALS AND METHODS: The study included 10 patients with biopsy-proven prostate cancer who underwent 3 Tesla prostate MRI. Diffusion-weighted MRI (DWI) data were acquired at b = 0, 750, and 1500 s/mm(2) . For each b-value, data were acquired at TEs of 47, 75, and 100 ms. ADC and T2 were measured as a function of b-value and TE, respectively, in 15 cancer and 10 normal regions of interest (ROIs). The Friedman test was used to test the significance of changes in ADC as a function of TE and of T2 as a function of b-value. RESULTS: In normal prostate ROIs, the ADC at TE of 47 ms is significantly smaller than ADC at TE of 100 ms (P = 0.0003) and T2 at b-value of 0 s/mm(2) is significantly longer than T2 at b-value of 1500 s/mm(2) (P = 0.001). In cancer ROIs, average ADC and T2 values do not change as a function of TE and b-value, respectively. However, in many cancer pixels, there are large decreases in the ADC as a function of TE and large increases in T2 as a function of b-value. Cancers are more conspicuous in ADC maps at longer TEs. CONCLUSION: Parameters derived from hybrid imaging that depend on coupled/associated values of ADC and T2 may improve the accuracy of MRI in diagnosing prostate cancer.

Prostate volumes derived from MRI and volume-adjusted serum prostate-specific antigen: correlation with Gleason score of prostate cancer.

OBJECTIVE: The purpose of this article is to study relationships between MRI-based prostate volume and volume-adjusted serum prostate-specific antigen (PSA) concentration estimates and prostate cancer Gleason score. MATERIALS AND METHODS: The study included 61 patients with prostate cancer (average age, 63.3 years; range 52-75 years) who underwent MRI before prostatectomy. A semiautomated and MRI-based technique was used to estimate total and central gland prostate volumes, central gland volume fraction (central gland volume divided by total prostate volume), PSA density (PSAD; PSA divided by total prostate volume), and PSAD for the central gland (PSA divided by central gland volume). These MRI-based volume and volume-adjusted PSA estimates were compared with prostatectomy specimen weight and Gleason score by using Pearson (r) or Spearman (ρ) correlation coefficients. RESULTS: The estimated total prostate volume showed a high correlation with reference standard volume (r = 0.94). Of the 61 patients, eight (13.1%) had a Gleason score of 6, 40 (65.6%) had a Gleason score of 7, seven (11.5%) had a Gleason score of 8, and six (9.8%) had a Gleason score of 9 for prostate cancer. The Gleason score was significantly correlated with central gland volume fraction (ρ = -0.42; p = 0.0007), PSAD (ρ = 0.46; p = 0.0002), and PSAD for the central gland (ρ = 0.55; p = 0.00001). CONCLUSION: Central gland volume fraction, PSAD, and PSAD for the central gland estimated from MRI examinations show a modest but significant correlation with Gleason score and have the potential to contribute to personalized risk assessment for significant prostate cancer.

Automatic prostate MR image segmentation with sparse label propagation and domain-specific manifold regularization.

Automatic prostate segmentation in MR images plays an important role in prostate cancer diagnosis. However, there are two main challenges: (1) Large inter-subject prostate shape variations; (2) Inhomogeneous prostate appearance. To address these challenges, we propose a new hierarchical prostate MR segmentation method, with the main contributions lying in the following aspects: First, the most salient features are learnt from atlases based on a subclass discriminant analysis (SDA) method, which aims to find a discriminant feature subspace by simultaneously maximizing the inter-class distance and minimizing the intra-class variations. The projected features, instead of only voxel-wise intensity, will be served as anatomical signature of each voxel. Second, based on the projected features, a new multi-atlases sparse label fusion framework is proposed to estimate the prostate likelihood of each voxel in the target image from the coarse level. Third, a domain-specific semi-supervised manifold regularization method is proposed to incorporate the most reliable patient-specific information identified by the prostate likelihood map to refine the segmentation result from the fine level. Our method is evaluated on a T2 weighted prostate MR image dataset consisting of 66 patients and compared with two state-of-the-art segmentation methods. Experimental results show that our method consistently achieves the highest segmentation accuracies than other methods under comparison.

MR imaging of ectopic pregnancy with an emphasis on unusual implantation sites.

Ectopic pregnancy (EP) is a life-threatening condition and remains the leading cause of death in the first trimester of pregnancy, although the mortality rate has significantly decreased over the past few decades because of earlier diagnoses and great improvements in treatment. EP is most commonly located in the ampullary portion of the fallopian tube and rarely in unusual sites such as the interstitium, cervix, cesarean scar, anomalous rudimentary horn of the uterus and peritoneal abdominal cavity. MRI may confirm or give additional information to ultrasonography, which is the most user-dependent imaging modality. Magnetic resonance imaging can accurately localize the site of abnormal implantation. It could be helpful for EP patient treatment by distinguishing the ruptured and unruptured cases before methotrexate treatment. MRI is quite sensitive to blood and can identify the hemorrhage phase.

Diffusion-weighted imaging in the characterization of focal liver lesions: efficacy of visual assessment.

OBJECTIVES: The objective of the study was to assess the value of visual assessment of signal intensities on b800 diffusion-weighted images and apparent diffusion coefficient (ADC) maps in differentiation of benign and malignant focal liver lesions (FLLs). METHODS: Approval for this retrospective study was obtained from the institutional review board. One hundred forty-three FLLs in 65 patients (38 women, 27 men; mean age, 50.8 years) underwent magnetic resonance (MR) imaging and diffusion-weighted imaging (DWI) with a respiratory-triggered single-shot echo-planar imaging sequence. Focal liver lesions were evaluated visually according to the signal intensities on b800 and ADC map images, and ADC values were also calculated. The conventional MR imaging, follow-up imaging findings, and histopathologic data were regarded as gold standard. Normal distribution was assessed with Kolmogorov-Smirnov test. The accuracies of visual assessment and ADC values in differentiating benign and malignant FLLs were assessed with the Student t test, and threshold values were determined with receiver operating characteristic curve analysis. RESULTS: By using a cutoff value of 1.21 × 10⁻³ mm²/s, ADC had a sensitivity of 100%, a specificity of 89.3%, and an accuracy of 92.3% in the discrimination of malignant FLLs. With the visual assessment of the DWIs and ADC maps, malignant lesions were differentiated from benign ones, with 100% sensitivity, 92.2% specificity, and 94.4% accuracy. Although some benign lesions were interpreted as malignant, no malignant lesion was determined as benign in visual assessment. CONCLUSIONS: Most FLLs are benign ones such as hemangiomas and cysts, which can be readily and practically characterized only by using visual assessment of DWIs without requiring time-consuming conventional and dynamic contrast-enhanced imaging sequences. Some benign lesions that are falsely interpreted as malignant can be further characterized by using conventional and contrast-enhanced MR studies.