High Diffusion-weighted Magnetic Resonance Imaging Research Articles

Case series multilocular cystic hemangioma of the liver: Three cases and literature review.

Multilocular cystic hemangioma is a rare benign tumor classified as an atypical hemangioma. Currently, there are limited imaging reports available, and the imaging characteristics can be challenging to distinguish from other malignant multilocular cystic liver diseases such as cystadenocarcinoma, necessitating confirmation through pathological diagnosis. Here, we discuss the imaging features of 3 cases of multilocular cystic hemangiomas. Case 1 was a 24-year-old young female, and Case 2 involved a 60-year-old elderly male. Both patients were asymptomatic and physical examination revealed hepatic space-occupying lesions. Imaging findings revealed multilocular cystic lesions in the left liver with septa, calcification, a high diffusion-weighted magnetic resonance imaging (DWI) signal at the edge of the lesion, and progressive enhancement of the cyst wall and septa. Case 3 involved a 50-year-old male patient with epigastric distending pain for 1 month and sudden severe abdominal pain for 14 hours. Imaging results revealed a multilocular cystic lesion in the left liver with septa and tumor bleeding, a high DWI signal, and an enhanced cyst wall and septa. The pathological diagnosis confirmed a hepatic hemangioma. All 3 patients underwent liver tumor resection. All 3 patients recovered successfully without any intraoperative or postoperative complications during the follow-up periods of 5 years, 6 months, and 5 months. There were no signs of recurrence. Liver imaging revealed multilocular cystic lesions with features, such as compartmentalization, calcification, or bleeding. Multilocular cystic hemangiomas should be considered in imaging diagnosis. Enhancing our understanding of multilocular cystic hemangiomas can aid in improving the differential diagnosis of other malignant multilocular cystic liver diseases, ultimately reducing unnecessary liver resection.

Diffusion-weighted Renal MRI at 9.4\u2009Tesla Using RARE to Improve Anatomical Integrity

Diffusion-weighted magnetic resonance imaging (DWI) is a non-invasive imaging technique sensitive to tissue water movement. By enabling a discrimination between tissue properties without the need of contrast agent administration, DWI is invaluable for probing tissue microstructure in kidney diseases. DWI studies commonly make use of single-shot Echo-Planar Imaging (ss-EPI) techniques that are prone to suffering from geometric distortion. The goal of the present study was to develop a robust DWI technique tailored for preclinical magnetic resonance imaging (MRI) studies that is free of distortion and sensitive to detect microstructural changes. Since fast spin-echo imaging techniques are less susceptible to B0 inhomogeneity related image distortions, we introduced a diffusion sensitization to a split-echo Rapid Acquisition with Relaxation Enhancement (RARE) technique for high field preclinical DWI at 9.4 T. Validation studies in standard liquids provided diffusion coefficients consistent with reported values from the literature. Split-echo RARE outperformed conventional ss-EPI, with ss-EPI showing a 3.5-times larger border displacement (2.60 vs. 0.75) and a 60% higher intra-subject variability (cortex = 74%, outer medulla = 62% and inner medulla = 44%). The anatomical integrity provided by the split-echo RARE DWI technique is an essential component of parametric imaging on the way towards robust renal tissue characterization, especially during kidney disease.

Early diffusion-weighted imaging and outcome prediction of comatose survivors after suicidal hanging

PurposeEarly outcome prediction after suicidal hanging is challenging in comatose survivors. We analysed the early patterns of brain diffusion-weighted magnetic resonance imaging (DWI) abnormalities in comatose survivors after suicidal hanging. MethodsAfter suicidal hanging, 18 comatose survivors were prospectively evaluated from January 2013 to December 2016. DWI was performed within 3 h after hanging in comatose survivors. We evaluated Utstein style variables and analysed abnormal spatial profile of signal intensity on DWI, brain apparent diffusion coefficient (ADC) values, and qualitative DWI scores to predict neurological outcomes. ResultsAll hanging associated cardiac arrest (CA) patients demonstrated bad neurological outcomes; 80% of non-CA comatose patients experienced good neurological outcomes. In hanging survivors with CA, cortical grey matter structures and deep grey nuclei exhibited profound ADC reductions and high DWI scores within 3 h after hanging, which was associated with diffuse anoxic brain damage with poor cerebral performance categories scores. CA comatose survivors had significantly lower ADC values and higher DWI scores compared to non-CA comatose survivors in the cortex and deep grey nuclei. ConclusionAlthough the presence of CA is the most important clinical prognosticator in hanging-associated comatose survivors, HSI abnormalities and low ADC values in the cortex and deep grey nuclei on DWI performed within 3 h after hanging are well-correlated with unfavourable outcomes regardless of therapeutic hypothermia. Therefore, early DWI may increase the sensitivity of poor outcome prediction and may be an effective combinatorial screening method when available prognostic variables are not reliable or conclusive.

High resolution diffusion weighted magnetic resonance imaging of the pancreas using reduced field of view single-shot echo-planar imaging at 3 T

Diffusion weighted magnetic resonance imaging (DWI) has been mostly acquired using single-shot echo-planar imaging (ss EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in ss EPI especially for abdominal imaging, even with the advances in parallel imaging. A novel method of reduced Field of View ss EPI (rFOV ss EPI) has achieved high resolution DWI in human carotid artery, spinal cord with reduced blurring and higher spatial resolution than conventional ss EPI, but it has not been used to pancreas imaging. In the work, comparisons between the full FOV ss-DW EPI and rFOV ss-DW EPI in image qualities and ADC values of pancreatic tumors and normal pancreatic tissues were performed to demonstrate the feasibility of pancreatic high resolution rFOV DWI. There were no significant differences in the mean ADC values between full FOV DWI and rFOV DWI for the 17 subjects using b=600s/mm2 (P=0.962). However, subjective scores of image quality was significantly higher at rFOV ss DWI (P=0.008 and 0.000 for b-value=0s/mm2 and 600s/mm2 respectively). The spatial resolution of DWI for pancreas was increased by a factor of over 2.0 (from almost 3.0mm/pixel to 1.25mm/pixel) using rFOV ss EPI technique. Reduced FOV ss EPI can provide good DW images and is promising to benefit applications for pancreatic diseases.

High b-value diffusion-weighted magnetic resonance imaging for gallbladder lesions: differentiation between benignity and malignancy

Recently, the clinical application of diffusion-weighted magnetic resonance imaging (DWI) has been expanding to abdominal organs. However, only a few studies on gallbladder diseases have been published. The aim of this study was to evaluate the usefulness and limitations of high b-value DWI for gallbladder diseases. A total of 153 patients (mean age 60 ± 15 years, 78 males) who had undergone DWI for evaluating gallbladder wall thickening or polypoid lesions were included in this study. Of these 153 patients, 36 had gallbladder cancer and 117 had benign gallbladder diseases (67 chronic cholecystitis, 44 adenomyomatosis, four cholesterol polyp, one gallbladder adenoma, and one xanthogranulomatous cholecystitis). We evaluated the positive signal rate with DWI and the apparent diffusion coefficient (ADC) value of each disease. The positive signal rate with DWI was significantly higher in gallbladder cancer (78 %) than in benign gallbladder diseases (22 %) (p < 0.001). The mean ADC value of gallbladder cancer was (1.83 ± 0.69) × 10(-3) mm(2)/s and that of benign gallbladder diseases was (2.60 ± 0.54) × 10(-3) mm(2)/s (p < 0.001). Benign gallbladder diseases with acute cholecystitis or a history of that had a higher positive signal rate with DWI (p < 0.001) and a lower ADC value (p = 0.018) than those without such conditions. DWI can contribute to the improvement of the diagnostic capability for gallbladder wall thickening or polypoid lesions by compensating for weaknesses of other modalities by its many advantages, although cases with acute cholecystitis or such history sometimes show false-positive on DWI.

Pretreatment Prediction of Brain Tumors Response to Radiation Therapy Using High b-Value Diffusion-Weighted MRI

Diffusion-weighted magnetic resonance imaging (DWMRI) is sensitive to tissues' biophysical characteristics, including apparent diffusion coefficients (ADCs) and volume fractions of water in different populations. In this work, we evaluate the clinical efficacy of DWMRI and high diffusion-weighted magnetic resonance imaging (HDWMRI), acquired up to b = 4000 sec/mm2 to amplify sensitivity to water diffusion properties, in pretreatment prediction of brain tumors' response to radiotherapy. Twelve patients with 20 brain lesions were studied. Six ring-enhancing lesions were excluded due to their distinct diffusion characteristics. Conventional and DWMRI were acquired on a 0.5-T MRI. Response to therapy was determined from relative changes in tumor volumes calculated from contrast-enhanced Ti-weighted MRI, acquired before and a mean of 46 days after beginning therapy. ADCs and a diffusion index, RD, reflecting tissue viability based on water diffusion were calculated from DWMRIs. Pretreatment values of ADC and RD were found to correlate significantly with later tumor response/nonresponse (r = 0.76, P < .002 and r = 0.77, P < .001). This correlation implies that tumors with low pretreatment diffusion values, indicating high viability, will respond better to radiotherapy than tumors with high diffusion values, indicating necrosis. These results demonstrate the feasibility of using DWMRI for pretreatment prediction of response to therapy in patients with brain tumors undergoing radiotherapy.

Early detection of response to radiation therapy in patients with brain malignancies using conventional and high b-value diffusion-weighted magnetic resonance imaging.

To study the feasibility of using diffusion-weighted magnetic resonance imaging (DWMRI), which is sensitive to the diffusion of water molecules in tissues, for detection of early tumor response to radiation therapy; and to evaluate the additional information obtained from high DWMRI, which is more sensitive to low-mobility water molecules (such as intracellular or bound water), in increasing the sensitivity to response. Standard MRI and DWMRI were acquired before and at regular intervals after initiating radiation therapy for 10 malignant brain lesions in eight patients. One week posttherapy, three of six responding lesions showed an increase in the conventional DWMRI parameters. Another three responding lesions showed no change. Four nonresponding lesions showed a decrease or no change. The early change in the diffusion parameters was enhanced by using high DWMRI. When high DWMRI was used, all responding lesions showed increase in the diffusion parameter and all nonresponding lesions showed no change or decrease. Response was determined by standard MRI 7 weeks posttherapy. The changes in the diffusion parameters measured 1 week after initiating treatment were correlated with later tumor response or no response (P <.006). This correlation was increased to P <.0006 when high DWMRI was used. The significant correlation between changes in diffusion parameters 1 week after initiating treatment and later tumor response or no response suggests the feasibility of using DWMRI for early, noninvasive prediction of tumor response. The ability to predict response may enable early termination of treatment in nonresponding patients, prevent additional toxicity, and allow for early changes in treatment.