Diffusion Weighted Imaging With Background Suppression Research Articles

Utility of Echo-planar Imaging with Compressed Sensitivity Encoding (EPICS) in the Evaluation of Small Breast Cancers Using Diffusion-weighted Imaging with Background Suppression (DWIBS).

High b-value acquisition and diffusion-weighted imaging with background suppression (DWIBS) are desirable in high-specificity breast cancer diagnosis on non-contrast-enhanced magnetic resonance imaging; however, this inherently results in a lower signal-to-noise ratio (SNR). Compressed sensitivity encoding (C-SENSE), which combines SENSE with compressed sensing, improves the SNR by reducing noise. Recent technological improvements allow us to incorporate this acceleration technique into echo-planar imaging, called echo-planar imaging with C-SENSE (EPICS). This study aimed to compare image quality and reliability of the apparent diffusion coefficient (ADC) between DWIBS obtained using SENSE and EPICS in patients with small breast cancers. Thirty-seven patients with pathologically confirmed breast cancer underwent DWIBS, and images were reconstructed using both conventional SENSE (SENSE-DWIBS) and EPICS (EPICS-DWIBS). Two board-certified radiologists independently evaluated lesion conspicuity (LC) and noise using a 5-point grading scale. The same 2 radiologists independently measured SNR, contrast-to-noise ratio (CNR), and the mean cancer ADC. The Pearson coefficient and Bland-Altman plot were applied to assess the accuracy of ADCs. LC scores were higher with EPICS than with SENSE, reaching significance for one reviewer but not the other reviewer. Noise ratings on visual evaluation were significantly lower with EPICS than with SENSE (P < 0.001 for both reviewers). SNR was significantly higher with EPICS than with SENSE (P < 0.005 for both reviewers). CNR was significantly higher with EPICS than with SENSE (P < 0.001 for both reviewers). Bland-Altman plots of cancer ADCs using EPICS-DWIBS and SENSE-DWIBS showed excellent concordance, with a bias of 0.026 × 10-3 mm2/s and limits of agreement ranging 0.054 × 10-3 mm2/s; the Pearson's correlation coefficient was 0.997 (P < 0.0001). EPICS enhances breast DWIBS image quality, with improved SNR and CNR and reduced noise levels. The ADCs of breast cancers obtained using EPICS were almost perfectly correlated with those obtained using conventional SENSE.

Comparison Between a Modified Fast 3-Dimensional Turbo Spin-Echo and Diffusion-Weighted Imaging With Background Suppression in Evaluation of Lumbosacral Plexus and Its Branches.

To compare the fast 3-dimensional NerveVIEW (3D NerveVIEW) with diffusion-weighted imaging with background suppression (DWIBS) in imaging of lumbosacral plexus and its branches. A prospective study was performed on 30 healthy volunteers and patients who had undergone compressed sensing 3D NerveVIEW and DWIBS scans. There were 11 healthy subjects, 15 patients with lumbar disc herniation, and 4 patients with chronic inflammatory demyelinating polyradiculoneuropathy. Image quality was rated using a 4-point subjective scale. Quantitative evaluation of the nerves was done by measuring signal-to-noise ratio, contrast-to-noise ratio, and signal-to-background ratio, and the consistency in the measurements of nerve root cross-sectional areas was also assessed. The differences of signal-to-noise ratio, contrast-to-noise ratio, signal-to-background ratio, and the scores of image quality between 2 sequences were compared. The overall average image quality score of 3D NerveVIEW was significantly higher than that of DWIBS (2.72 ± 0.45 and 2.45 ± 0.81, respectively; P < 0.01). In terms of individual nerves, there was no significant difference between the 2 sequences in the display of the nerves from L2 to S1; however, 3D NerveVIEW was significantly better than DWIBS in demonstration of the S2-S3 nerves, as well as the nerve details. Regarding quantitative measurements, these sequences achieved comparable results with excellent interobserver agreements. Fast 3D NerveVIEW was superior to DWIBS with improved conspicuity of small distal nerves of S2-S3 and nerve details.

Utility of the Diffusion Weighted Sequence in Gynecological Imaging: Review Article.

Simple SummaryDiffusion weighted imaging (DWI) is a magnetic resonance imaging sequence with diverse clinical applications in malignant and nonmalignant gynecological conditions. It provides vital supplemental information in the diagnosis and management of various gynecological conditions. Radiologists should be aware of fundamental concepts, clinical applications and pitfalls of DWI. Additionally we briefly discuss potential scope of newer advanced techniques based on DWI including diffusion tensor imaging and diffusion-weighted whole-body imaging with background signal suppression.Functional imaging with diffusion-weighted imaging (DWI) is a complementary tool to conventional diagnostic magnetic resonance imaging sequences. It is being increasingly investigated to predict tumor response and assess tumor recurrence. We elucidate the specific technical modifications of DWI preferred for gynecological imaging, including the different b-values and planes for image acquisition. Additionally, we discuss the problems and potential pitfalls encountered during DWI interpretation and ways to overcome them. DWI has a wide range of clinical applications in malignant and non-malignant gynecological conditions. It provides supplemental information helpful in diagnosing and managing tubo-ovarian abscess, uterine fibroids, endometriosis, adnexal torsion, and dermoid. Similarly, DWI has diverse applications in gynecological oncology in diagnosis, staging, detection of recurrent disease, and tumor response assessment. Quantitative evaluation with apparent diffusion coefficient (ADC) measurement is being increasingly evaluated for correlation with various tumor parameters in managing gynecological malignancies aiding in preoperative treatment planning. Newer advanced DWI techniques of diffusion tensor imaging (DTI) and whole body DWI with background suppression (DWIBS) and their potential uses in pelvic nerve mapping, preoperative planning, and fertility-preserving surgeries are briefly discussed.

Usefulness of magnetic resonance enterography in detecting signs of sacroiliitis in young patients with inflammatory bowel disease

BackgroundArthritis is often an underestimated extraintestinal manifestation in pediatric inflammatory bowel disease (IBD), including sacroiliitis, whose early signs are well detectable at magnetic resonance imaging (MRI). Magnetic resonance enterography (MRE) is an accurate imaging modality for pediatric IBD assessment.We studied the possibility to detect signs of sacroiliac inflammation in a group of children with IBD who underwent MRE for gastrointestinal disease evaluation.MethodsWe retrospectively reviewed MRE scans performed in pediatric patients with IBD. We looked for signs of sacroiliitis taking the ASAS (Assessment of SpondyloArthritis international Society) criteria as a model. Presence of bone marrow edema (using T2W sequences with fat suppression), diffusion restriction in Diffusion Weighted Imaging (DWI) or Diffusion Weighted Imaging with Background Suppression (DWIBS), and dynamic contrast enhancement were evaluated. Each SI joint was divided into 4 quadrants: upper iliac, lower iliac, upper sacral, and lower sacral. Two blinded observers with experience in pediatric and skeletal imaging independently evaluated the images. Cases upon which there was a disagreement were evaluated by the two reviewing radiologists and a third radiologist with similar experience together.ResultsWe enrolled 34 patients (24 males and 10 females, with mean age at scanning 14.3 years, median 15.3 years; 2 affected by ulcerative colitis, 32 by Crohn’s disease) for a total of 59 examinations performed at the time of their first diagnosis or at symptom exacerbations. No patient complained of musculoskeletal symptoms, neither had pathological findings at articular examination. At the time of MRE 25 patients were under treatment for their IBD. Five patients had radiological signs of SI inflammation at MRE, albeit of mild degree. All patients with SI joint edema also had a restricted diffusion in DWIBS or DWI and almost everyone had contrast media uptake.ConclusionsSacroiliitis is one of the extraintestinal manifestation associated with IBD; it is often asymptomatic and clinically underdetected, with an unrelated progression with respect to the underlying IBD. MRE offers the possibility to study SI joints in young patients with IBD who undergo MRE for the investigation of their intestinal condition. Furthermore, we observed that gadolinium enhancement does not improve diagnostic specificity in sacroiliiitis detection.

Clinical Value and Diagnostic Accuracy of 3.0T Multi-Parameter Magnetic Resonance Imaging in Traumatic Brachial Plexus Injury.

BackgroundThe aim of this study was to evaluate the clinical value and diagnostic accuracy of 3.0T multi-parameter magnetic resonance imaging (MRI) in traumatic brachial plexus injury.Material/MethodsTwenty-five healthy volunteers and 28 patients with clinically confirmed traumatic brachial plexus injury were enrolled in this study. Bilateral brachial plexus imaging was performed using conventional sequences (T1WI, T2WI), short time inversion recovery (STIR), balanced fast field echo (balance-FFE), and diffusion weighted imaging with background suppression (DWIBS). The MRI diagnosis was compared with intraoperative electromyography and surgery.ResultsBrachial plexus injuries were classified based on the anatomic locations. There were 16 patients with pre-ganglionic injury and 12 patients with post-ganglionic injury. The pre-ganglionic injury included ruptured nerve roots, stiff nerve roots, traumatic meningeal cysts, black line sign, spinal cord edema, and thickened nerve root sleeve. The post-ganglionic injury included thickened nerve roots, disappearance of normal nerve root structure or disrupted continuity of the nerve, stiff nerve roots, pseudo-neuroma, and abnormalities in the adjacent soft tissues. Comparing the results from MRI and surgery, the sensitivity, specificity, and accuracy of MRI examination were 93.55%, 71.43%, and 89.47% respectively for preganglionic injury, and 91.30%, 60.00%, and 85.71% respectively for postganglionic injury.ConclusionsThe combination of STIR, balance-FFE, and DWIBS sequences can display brachial plexus pre-ganglionic and post-ganglionic injury clearly, effectively, and accurately.

Whole-body MRI for metastatic cancer detection using T2 -weighted imaging with fat and fluid suppression.

To develop a whole-body MRI technique at 3T with improved lesion conspicuity for metastatic cancer detection using fast, high-resolution and high SNR T2 -weighted (T2 W) imaging with simultaneous fat and fluid suppression. The proposed dual-echo T2 -weighted acquisition for enhanced conspicuity of tumors (DETECT) acquires 4 images, in-phase (IP) and out-of-phase (OP) at a short and a long TE using single-shot turbo spin echo. The IP/OP images at the short and long TEs are reconstructed using the standard Dixon and shared-field-map Dixon reconstruction respectively, for robust fat-water separation. An adaptive complex subtraction between the 2 TE water-only images achieves fluid attenuation. DETECT imaging was optimized and evaluated in whole-body imaging of 5 healthy volunteers, and compared against diffusion-weighted imaging with background suppression (DWIBS) in 5 patients with known metastatic renal cell carcinoma. Robust fat-water separation and fluid attenuation were achieved using the shared-field-map Dixon reconstruction and adaptive complex subtraction, respectively. DETECT imaging technique generated co-registered T2 W images with and without fat suppression, heavily T2 W, and fat and fluid suppressed T2 W whole-body images in <7 min. Compared to DWIBS acquired in 17 min, the DETECT imaging achieved better detection and localization of lesions in patients with metastatic cancer. DETECT imaging technique generates T2 W images with high resolution, high SNR, minimal geometric distortions, and provides good lesion conspicuity with robust fat and fluid suppression in <7 min for whole-body imaging, demonstrating efficient and reliable metastatic cancer detection at 3T.

Prediction of malignancy by a radiomic signature from contrast agent-free diffusion MRI in suspicious breast lesions found on screening mammography.

To assess radiomics as a tool to determine how well lesions found suspicious on breast cancer screening X-ray mammography can be categorized into malignant and benign with unenhanced magnetic resonance (MR) mammography with diffusion-weighted imaging and T2 -weighted sequences. From an asymptomatic screening cohort, 50 women with mammographically suspicious findings were examined with contrast-enhanced breast MRI (ceMRI) at 1.5T. Out of this protocol an unenhanced, abbreviated diffusion-weighted imaging protocol (ueMRI) including T2 -weighted, (T2 w), diffusion-weighted imaging (DWI), and DWI with background suppression (DWIBS) sequences and corresponding apparent diffusion coefficient (ADC) maps were extracted. From ueMRI-derived radiomic features, three Lasso-supervised machine-learning classifiers were constructed and compared with the clinical performance of a highly experienced radiologist: 1) univariate mean ADC model, 2) unconstrained radiomic model, 3) constrained radiomic model with mandatory inclusion of mean ADC. The unconstrained and constrained radiomic classifiers consisted of 11 parameters each and achieved differentiation of malignant from benign lesions with a .632 + bootstrap receiver operating characteristics (ROC) area under the curve (AUC) of 84.2%/85.1%, compared to 77.4% for mean ADC and 95.9%/95.9% for the experienced radiologist using ceMRI/ueMRI. In this pilot study we identified two ueMRI radiomics classifiers that performed well in the differentiation of malignant from benign lesions and achieved higher performance than the mean ADC parameter alone. Classification was lower than the almost perfect performance of a highly experienced breast radiologist. The potential of radiomics to provide a training-independent diagnostic decision tool is indicated. A performance reaching the human expert would be highly desirable and based on our results is considered possible when the concept is extended in larger cohorts with further development and validation of the technique. 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:604-616.

Fast and Noninvasive Characterization of Suspicious Lesions Detected at Breast Cancer X-Ray Screening: Capability of Diffusion-weighted MR Imaging with MIPs.

To evaluate the ability of a diagnostic abbreviated magnetic resonance (MR) imaging protocol consisting of maximum intensity projections (MIPs) from diffusion-weighted imaging with background suppression (DWIBS) and unenhanced morphologic sequences to help predict the likelihood of malignancy on suspicious screening x-ray mammograms, as compared with an abbreviated contrast material-enhanced MR imaging protocol and a full diagnostic breast MR imaging protocol. This prospective institutional review board-approved study included 50 women (mean age, 57.1 years; range, 50-69 years), who gave informed consent and who had suspicious screening mammograms and an indication for biopsy, from September 2014 to January 2015. Before biopsy, full diagnostic contrast-enhanced MR imaging was performed that included DWIBS (b = 1500 sec/mm(2)). Two abbreviated protocols (APs) based on MIPs were evaluated regarding the potential to exclude malignancy: DWIBS (AP1) and subtraction images from the first postcontrast and the unenhanced series (AP2). Diagnostic indexes of both methods were examined by using the McNemar test and were compared with those of the full diagnostic protocol and histopathologic findings. Twenty-four of 50 participants had a breast carcinoma. With AP1 (DWIBS), the sensitivity was 0.92 (95% confidence interval [CI]: 0.73, 0.98), the specificity was 0.94 (95% CI: 0.77, 0.99), the negative predictive value (NPV) was 0.92 (95% CI: 0.75, 0.99), and the positive predictive value (PPV) was 0.93 (95% CI: 0.75, 0.99). The mean reading time was 29.7 seconds (range, 4.9-110.0 seconds) and was less than 3 seconds (range, 1.2-7.6 seconds) in the absence of suspicious findings on the DWIBS MIPs. With the AP2 protocol, the sensitivity was 0.85 (95% CI: 0.78, 0.95), the specificity was 0.90 (95% CI: 0.72, 0.97), the NPV was 0.87 (95% CI: 0.69, 0.95), the PPV was 0.89 (95% CI: 0.69, 0.97), and the mean reading time was 29.6 seconds (range, 6.0-100.0 seconds). Unenhanced diagnostic MR imaging (DWIBS mammography), with an NPV of 0.92 and an acquisition time of less than 7 minutes, could help exclude malignancy in women with suspicious x-ray screening mammograms. The method has the potential to reduce unnecessary invasive procedures and emotional distress for breast cancer screening participants if it is used as a complement after the regular screening clarification procedure.

Evaluation of image quality of DWIBS versus DWI sequences in thoracic MRI at 3 T

PurposeTo compare diffusion weighted imaging with background suppression (DWIBS) sequence with classic spectral diffusion sequence (DWI) with and without respiratory gating in mediastinal lymph node analysis at 3T. Materials and methods26 patients scheduled for mediastinoscopic lymph node analysis, prospectively undergone a thoracic 3T MRI with DWIBS (FatSat=STIR; TR/TE=6674.1/44.7ms; IR=260ms) and DWI sequences (FatSat=SPIR; TR/TE=1291/59.6ms) (b=0-400-800s/mm2) with and without (free breathing) respiratory gating.Images at b=800 were analyzed by two radiologists. They performed qualitative analysis of fat-sat homogeneity and motion artifacts, rated from 0 to 4, and quantitative evaluation by studying signal to background (STB) of lymph nodes. ResultsQuality of fat suppression was significantly higher for DWIBS than for DWI both for free-breathing (score 3.48±0.65 vs. 1.76±0.96, p<0.0001) and respiratory-gated scans (3.17±0.77 vs. 1.72±0.73, p=0.0001). Similarly, artifacts were reduced with DWIBS (3.16±0.47 vs. 1.76±0.59, p<0.0001; 3.0±0.73 vs. 2.04±0.53, p=0.0001). Quantitative analysis showed higher STB with DWIBS (3.26±1.83 vs. 0.98±0.44, p<0.0001; 3.56±, 2.09 vs. 0.92±0.59, p<0.0001). Gating did not improve image quality and STB on DWIBS (p>0.05). ConclusionIn thoracic MRI, ungated DWIBS sequence improves fat-sat homogeneity, reduces motion artifacts and increases STB of lymph nodes. Respiratory gating does not improve DWIBS image quality.

High field magnetic resonance background suppression diffusion imaging in the diagnosis of liver foci of space occupying lesion

To explore the diagnostic value of the 3.0T magnetic resonance liver diffusion weighted imaging with background suppression (DWIBS) in liver foci of space occupying lesion. A total of 43 cases of liver bureau stove perch pathological change were included: 15 were hepatocellular carcinoma (HCC) with 24 lesions; 7 were liver metastatic tumor with 13 lesions; 10 were liver hemangioma with 12 lesions; and 11 liver cyst with 20 lesions. After taking the conventional T1WI and T2WI sequence, the magnetic resonance background suppression diffusion imaging technology (diffusion weighted imaging with background suppression, DWIBS) was applied, following the dynamic enhanced scan. With the MRI to DWIBS workstation for classifying positron emission computed tomography (PET) processing, the T2WI diagram and dynamic enhanced diagram were compared respectively for the 3 sequences of lesion detection rate, T2WI, and DWIBS, to enhance the delay time between the two joint and combined lesion detection rate. With the MRI workstation software scanning image generation ADC diagram, the ADC values were measured for liver cancer, liver metastatic tumor, liver hemangioma and liver cysts. The 3 sequences of detection rates of the T2WI, DWIBS and enhanced delay period T1WI were 91.3%, 94.2%, and 95.6%. The detection rate of DWIBS plus T2WI was 92.7%; that of T2WI plus enhanced delay time was 94.9%, and that of DWIBS plus enhanced delay time was 96.3%, with the rate of DWIBS plus enhanced delay period obviously higher than that of the DWIBS plus T2WI (P<0.05). The ADC value of the benign liver tumor was obviously higher than that of the malignant tumors: hepatic cyst (2.614 ± 0.57)×10⁻³ mm²/s, liver hemangioma (2.055 ± 0.21)×10⁻³ mm²/s, metastatic carcinoma (1.374 ± 0.32)× 10⁻³ mm²/s, and liver cancer (1.287 ± 0.14)×10⁻³ mm²/s. Except for the liver cancer and the liver metastatic tumor, there was significant difference between the other groups (P<0.05). Combing the DWIBS technology, the PET-like images and the ADC value acquired, the combined enhanced sequences could further facilitate the demonstration of the liver foci of space occupying lesion, the accuracy of identification and diagnosis of the liver foci of space occupying lesion.

Diagnosis value of 3.0 T diffusion-weighted imaging with background suppression magnetic resonance for metastatic lymph nodes in rectal cancer

To evaluate the diagnostic value of 3.0 T diffusion-weighted imaging with background suppression (DWIBS) magnetic resonance (MR) for lymph node metastasis in rectal cancer. Thirty-five patients with rectal cancer who underwent preoperative routine MRI+DWI examination were enrolled in the study and were treated by rectal cancer resection plus lymph node dissection. Metastatic and non-metastatic lymph nodes were confirmed by postoperative pathology. Apparent diffusion coefficient (ADC) values, long-axis and short-axis diameters of lymph nodes were measured. Receiver operating characteristic (ROC) curve was used to assess the diagnostic efficacy of ADC, long-axis and short-axis diameters for differentiating metastatic lymph nodes from non-metastatic lymph nodes. A total of 151 lymph nodes were confirmed with exact location in 35 patients. Sixty-five metastatic lymph nodes and 86 non-metastatic lymph nodes were identified. The ADC values of metastatic lymph nodes and non-metastatic lymph nodes were(0.86±0.14)×10(-3) and (0.94±0.16)×10(-3) mm(2)/s respectively. The long-axis diameter were(9.78±3.13) and (7.90±1.77) mm, respectively. The short-axis diameter were (7.65±2.00) and (6.45±1.19) mm, respectively. There were statistically significant differences between metastatic and non-metastatic lymph nodes in ADC values, long-axis diameter, and short-axis diameter(all P<0.01). The areas under the ROC curve of ADC value, long-axis diameter, and short-axis diameter were 0.648, 0.706, and 0.692, respectively. Optimal cutoff values for these parameters were 1.05×10(-3) mm(2)/s, 7.95 mm, and 5.90 mm, respectively, and the corresponding sensitivities and specificities were 93.8% and 30.2%, 75.4% and 61.6%, 90.8% and 38.4%. Quantitative measurement of ADC value may reflect the degree of diffusion restriction of metastatic lymph nodes by DWIBS at 3.0 T MR. Accurate diagnosis of metastatic lymph nodes in rectal cancer demands comprehensive evaluation combining ADC value with diameter measurement.

Signal characteristics of focal bone marrow lesions in patients with multiple myeloma using whole body T1w-TSE, T2w-STIR and diffusion-weighted imaging with background suppression

This study analyses the diagnostic potential of Diffusion-Weighted Imaging with Background Suppression (DWIBS) in the detection of focal bone marrow lesions from multiple myeloma. The signal and contrast properties of DWIBS are evaluated in correlation with the serum concentration of M-component (MC) and compared with established T1- and T2-weighted sequences. Data from 103 consecutive studies in 81 patients are analysed retrospectively. Signal intensities and apparent Diffusion Coefficients (ADC) of 79 focal lesions in the lumbar spine or pelvis of 38 patients are determined and contrast-to-noise-ratio (CNR) is calculated. Data from patients with low (<20 g/L) and high (>20 g/dL) MC are evaluated separately. Signal intensities of focal myeloma lesions on T2w-STIR vary significantly depending on the MC, which leads to a loss in CNR in patients with high MC. No signal variation is observed for T1w-TSE and DWIBS. The CNR values provided by DWIBS in patients with high MC are slightly higher than those of T2w-STIR. ADC values in patients with low MC are significantly higher than in patients with high MC. Whole-body DWIBS has the potential to improve the conspicuity of focal myeloma lesions and provides additional biological information by ADC quantification.