Non-contrast MR Research Articles

Reliability of signal intensity in the basal ganglia on non-contrast T1-weighted MR scans after repetitive application of a gadolinium-based contrast agent in pediatric neuro-oncology patients

PurposeTo evaluate the reliability of signal intensity (SI) changes in the basal ganglia as a supposed indicator of gadolinium deposition in the brain after repetitive application of gadolinium-based contrast agents (GBCAs) in a pediatric neuro-oncological collective. MethodsOne hundred and eight neuropediatric patients (54 male, 54 female, 0–17 years old), with repetitive GBCA-enhanced cranial MRIs between 2003 and 2017, were retrospectively analyzed. Two radiologists measured SI in the nucleus dentatus (ND), globus pallidus (GP), thalamus (T), and the pons (P). The NDP and GPT ratio were calculated. An intraclass correlation coefficient, and multiple linear regressions with subsequent stepwise backward variable selection were performed to evaluate the influence of gender, patient’s age at the first MRI, time interval between the first and last MRI, linear or macrocyclic GBCAs, residual pathology, treatments, and magnet field strengths. ResultsThe inter-reader agreement was good for GPT and NDP in the whole collective (ICC = 0.837 and ICC = 0.793) and for children >2 years of age (ICC = 0.874 and ICC = 0.790), but poor to moderate for children ≤2 years of age (ICC = 0.397 and ICC = 0.748). The intra-reader agreement was good (ICC = 0.910 and ICC = 0.882). An SI increase was only observed for both readers in GPT (p = 0.003, or p < 0.001). None of the considered cofactors showed a consistent effect on SI changes for either readers or regions. ConclusionMeasurements of SI changes in the basal ganglia are not a reliable parameter with which to evaluate or estimate gadolinium deposition in the brain or to identify suspicious influential factors after repeated GBCA applications.

Non-Contrast MR Lymphography and Intranodal Dynamic Contrast MR Lymphangiography in Children with Congenital Heart Disease-Imaging Findings as well as Impact on Patient Management and Outcome.

Lymphatic flow disorders are rare but devastating complications in children with congenital heart disease. T2-weighted magnetic resonance lymphography and intranodal dynamic contrast magnetic resonance lymphangiography are imaging modalities that can depict central lymphatic anatomy and flow pattern. Our objective was to describe the technical aspects and our imaging findings of central lymphatic abnormalities and their impact on patient management and outcomes: We conducted a retrospective review of 26 children with congenital heart disease who presented for lymphatic imaging between 2015 and 2020 at our institution. Eleven had postoperative chylothorax, six had plastic bronchitis, seven had protein-losing enteropathy and three had Noonan syndrome. Our lymphatic imaging demonstrated severely abnormal lymphatic flow in all of the children, but only minor abnormalities in protein-losing enteropathy. No major procedure-related complication occurred. Lymphatic interventions were performed in six patients, thoracic duct decompression in two patients and chylothorax revision in three patients. This led to symptomatic improvements in all of the patients: Lymphatic imaging is safe and essential for the diagnosis of lymphatic flow disorders and therapy planning. Our intranodal lymphangiography depicts an abnormal lymphatic flow pattern from the central lymphatics but failed to demonstrate an abnormal lymphatic flow in protein-losing enteropathy. These imaging techniques are the basis for selective lymphatic interventions, which are promising to treat lymphatic flow disorders.

Utilization of Noncontrast Magnetic Resonance Lymphangiography for Selection of Effective Surgical Method in Breast Cancer-Related Lymphedema.

Background and Objectives: When considering surgery for patients with breast cancer-related lymphedema (BCRL), it is crucial to determine which surgery will be most effective for the patient and establish the indications for each surgery. Our study retrospectively compared the results of preoperative noncontrast MR lymphangiography (NMRL) performed on the lymphedematous limb of patients before surgery, with the aim of analyzing whether preoperative NMRL can be used as a criterion for determining the type of surgery. Materials and Methods: From January 2020 to June 2022, a total of 138 patients with lymphedema underwent surgery at Seoul National University Bundang Hospital. All patients underwent preoperative NMRL imaging and were classified into stages 1-3 based on the MRI severity index using the authors' previous reference. Three types of surgery, LVA, LVA + liposuction, and LVA + VLNT, were conducted on all patients. The effectiveness of the surgery was evaluated one year postoperatively using the interlimb volume difference before and after surgery, the fluid volume of the edematous limb measured by bioimpedance spectroscopy, and the subjective satisfaction of the patients through the Lymph Q questionnaire. Results: In this study, out of a total of 138 patients, 26 (19%) were MRI stage 1, 62 (45%) were stage 2, and 50 (36%) were stage 3. Of the 83 patients who underwent LVA surgery, the greatest decrease in interlimb volume difference was observed in stage 2 patients, and subjective satisfaction was also the most effective in stage 2. In the case of LVA + liposuction patients, a significant volume decrease and a high satisfaction were observed in stage 3 patients. In the case of LVA + VLNT patients, there was no difference in volume decrease according to the stage, but a greater decrease in body fluid volume was observed as the MRI severity index score increased through BIA. Conclusions: In conclusion, this study demonstrates that NMRL imaging is a useful modality for determining the most effective surgical method and predicting the surgical outcome in patients with lymphedema. This highlights the importance of using NMRL in the treatment planning of lymphedema patients.

Current Imaging Strategies in Patients with Abdominal Aortic Aneurysms.

An abdominal aortic aneurysm (AAA) is defined as a localized dilatation of the abdominal aorta of ≥ 3 cm. With a prevalence of 4-8 %, AAA is one of the most common vascular diseases in Western society. Radiological imaging is an elementary component in the diagnosis, monitoring, and treatment planning of AAA patients. This is a narrative review article on preoperative imaging strategies of AAA, incorporating expert opinions based on the current literature and standard-of-care practices from our own center. Examples are provided to illustrate clinical cases from our institution. Radiological imaging plays a pivotal role in the initial diagnosis and monitoring of patients with AAA. Ultrasound is the mainstay imaging modality for AAA screening and surveillance. Contrast-enhanced CT angiography is currently considered the gold standard for preoperative imaging and image-based treatment planning in AAA repair. New non-contrast MR angiography techniques are robustly applicable and allow precise determination of aortic diameters, which is of critical importance, particularly with regard to current diameter-based surgical treatment guidelines. 3D imaging with multiplanar reformation and automatic centerline positioning enables more accurate assessment of the maximum aortic diameter. Modern imaging techniques such as 4D flow MRI have the potential to further improve individualized risk stratification in patients with AAA. · Ultrasound is the mainstay imaging modality for AAA screening and monitoring. · Contrast-enhanced CT angiography is the gold standard for preoperative imaging in AAA repair. · Non-contrast MR angiography allows for accurate monitoring of aortic diameters in AAA patients. · Measurement of aortic diameters is more accurate with 3D-CT/MRI compared to ultrasound. · Research seeks new quantitative imaging biomarkers for AAA risk stratification, e. g., using 4D flow MRI.

Radiomics analysis from magnetic resonance imaging in predicting the grade of nonfunctioning pancreatic neuroendocrine tumors: a multicenter study

ObjectivesTo explore the potential of radiomics features to predict the histologic grade of nonfunctioning pancreatic neuroendocrine tumor (NF-PNET) patients using non-contrast sequence based on MRI.MethodsTwo hundred twenty-eight patients with NF-PNETs undergoing MRI at 5 centers were retrospectively analyzed. Data from center 1 (n = 115) constituted the training cohort, and data from centers 2–5 (n = 113) constituted the testing cohort. Radiomics features were extracted from T2-weighted images and the apparent diffusion coefficient. The least absolute shrinkage and selection operator was applied to select the most important features and to develop radiomics signatures. The area under receiver operating characteristic curve (AUC) was performed to assess models.ResultsTumor boundary, enhancement homogeneity, and vascular invasion were used to construct the radiological model to stratify NF-PNET patients into grade 1 and 2/3 groups, which yielded AUC of 0.884 and 0.684 in the training and testing groups. A radiomics model including 4 features was constructed, with an AUC of 0.941 and 0.871 in the training and testing cohorts. The fusion model combining the radiomics signature and radiological characteristics showed good performance in the training set (AUC = 0.956) and in the testing set (AUC = 0.864), respectively.ConclusionThe developed model that integrates radiomics features with radiological characteristics could be used as a non-invasive, dependable, and accurate tool for the preoperative prediction of grade in NF-PNETs.Clinical relevance statementOur study revealed that the fusion model based on a non-contrast MR sequence can be used to predict the histologic grade before operation. The radiomics model may be a new and effective biological marker in NF-PNETs.Key PointsThe diagnostic performance of the radiomics model and fusion model was better than that of the model based on clinical information and radiological features in predicting grade 1 and 2/3 of nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs).Good performance of the model in the four external testing cohorts indicated that the radiomics model and fusion model for predicting the grades of NF-PNETs were robust and reliable, indicating the two models could be used in the clinical setting and facilitate the surgeons’ decision on risk stratification.The radiomics features were selected from non-contrast T2-weighted images (T2WI) and diffusion-weighted imaging (DWI) sequence, which means that the administration of contrast agent was not needed in grading the NF-PNETs.

Pancreatic cancer detection with a non-contrast MR protocol: is it reliable?

PurposeThe pancreatic cancer (PC) is the 4th leading cancer-related death, becoming the second one by 2030, with a 5 year survival rate of 8%. Considering its increased incidence in high-risk categories compared to the general population, we aimed to validate a non-contrast MR protocol, to detect PC in its earliest phase, which could be suitable as a screening tool in high-risk patients.Materials and methodsIn this retrospective study, we selected 200 patients (> 40 years) from our radiological database, which performed upper abdominal MRI between 2012 and 2017. 100 were negative for pancreatic lesions and 100 positive for pancreatic lesion (< 30 mm). The latter group included: 40 PDAC (pancreatic adenocarcinoma), 42 BD-IPMN (Branch Duct- Intraductal Papillary Mucinous Neoplasm), 10 PNET(pancreatic neuroendocrine tumor), 4 SCN(serous cystic neoplasm), 3 IPS(intrapancreatic spleen), 1 MCN(mucinous cystic neoplasm). Three readers (R1, R2 and R3) with a high, medium and low experience, respectively, analysed, first, the non-contrast MR sequences (single-shot T2w breath-hold, GE T1w FS, DWI and 2D/3D MRCP), and then the standard MR protocol, independently, randomly and anonymously. Readers identified or excluded the presence of pancreatic lesion, in both reading sessions. These results were compared with the histopathological diagnosis, and then divided into 3 different classes of lesions: all lesions, pancreatic adenocarcinoma and solid lesion. Mcnemar’s test was used to compare the results. The inter-observer agreement was determined according to the kappa statistic in both protocols, and then the inter-protocol agreement was calculated.ResultsThe non-contrast MR protocol has reached statistical parameters values ranging between 83% in SE (sensitivity) by R3 and 99% in NPV (negative predictive value) by R1. The standard MR protocol has reported slight increasing statistical parameters compared to those of the proposed one. However, there are not significant statistical differences between the both protocols. The proposed non-contrast MR protocol has reported the highest NPVs in the PDAC group detection (R1: 99%, R2: 99%, R3: 98%). In all groups of lesions, the agreement between the two protocols was excellent for each Reader ranging from 96 to 98%.ConclusionThe proposed non-contrast MR protocol showed high PC detection values and a time execution ≤ 20 min. Therefore, it can be proposed as a screening tool in high-risk patients.

Non-Contrast Enhanced Magnetic Resonance Venography Using the Fast Imaging Employing Steady-State Acquisition (FIESTA) Pulse Sequence in Preoperative Evaluation of Liver Donors: Can it Replace CT Venography?

Background: Liver transplantation has now become the preferred treatment for patients with liver failure. Pre-operative assessment of hepatic/portal vein anatomy of donors is necessary for which CT venography is most commonly used but it exposes the donors to huge radiation burden. To avoid this, non-contrast MR venography is the most preferred alternative for evaluation of veins. Objective: To determine diagnostic yield of magnetic resonance venography using Fast Imaging Employing Steady-State Acquisition (FIESTA) pulse sequence in comparison to computed tomography venography for the determination of portal/hepatic venous anatomy of potential liver donors. Methods: Retrospective study was conducted in which the venous phase CT scan and FIESTA (b-SSFP) sequence of 50 potential liver donors between 01-07-2021 and 30-11-2021 were reviewed. The hepatic and portal venous anatomy was reviewed. The assessment comprised the type of portal venous anatomy, the number of prominent tributaries from segment VIII and V of liver having diameter of 4mm or more emptying into the middle hepatic vein and the total number of accessory inferior right hepatic veins from segment VI and VII emptying into inferior vena cava (IVC). Results: With 100% sensitivity and specificity, the FIESTA sequence precisely identified the portal vein anatomy, total number of accessory inferior right hepatic veins, and the total number of 4 mm thick tributaries from segment V and VIII draining into middle hepatic vein Conclusion: We propose that magnetic resonance venography using FIESTA sequence can be used instead of CT venography to determine hepatic and portal vein anatomy of liver donors.

Synthetic Inflammation Imaging with PatchGAN Deep Learning Networks.

Background: Gadolinium (Gd)-enhanced Magnetic Resonance Imaging (MRI) is crucial in several applications, including oncology, cardiac imaging, and musculoskeletal inflammatory imaging. One use case is rheumatoid arthritis (RA), a widespread autoimmune condition for which Gd MRI is crucial in imaging synovial joint inflammation, but Gd administration has well-documented safety concerns. As such, algorithms that could synthetically generate post-contrast peripheral joint MR images from non-contrast MR sequences would have immense clinical utility. Moreover, while such algorithms have been investigated for other anatomies, they are largely unexplored for musculoskeletal applications such as RA, and efforts to understand trained models and improve trust in their predictions have been limited in medical imaging. Methods: A dataset of 27 RA patients was used to train algorithms that synthetically generated post-Gd IDEAL wrist coronal T1-weighted scans from pre-contrast scans. UNets and PatchGANs were trained, leveraging an anomaly-weighted L1 loss and global generative adversarial network (GAN) loss for the PatchGAN. Occlusion and uncertainty maps were also generated to understand model performance. Results: UNet synthetic post-contrast images exhibited stronger normalized root mean square error (nRMSE) than PatchGAN in full volumes and the wrist, but PatchGAN outperformed UNet in synovial joints (UNet nRMSEs: volume = 6.29 ± 0.88, wrist = 4.36 ± 0.60, synovial = 26.18 ± 7.45; PatchGAN nRMSEs: volume = 6.72 ± 0.81, wrist = 6.07 ± 1.22, synovial = 23.14 ± 7.37; n = 7). Occlusion maps showed that synovial joints made substantial contributions to PatchGAN and UNet predictions, while uncertainty maps showed that PatchGAN predictions were more confident within those joints. Conclusions: Both pipelines showed promising performance in synthesizing post-contrast images, but PatchGAN performance was stronger and more confident within synovial joints, where an algorithm like this would have maximal clinical utility. Image synthesis approaches are therefore promising for RA and synthetic inflammatory imaging.

Functional lung imaging using novel and emerging MRI techniques.

Respiratory diseases are leading causes of death and disability in the world. While early diagnosis is key, this has proven difficult due to the lack of sensitive and non-invasive tools. Computed tomography is regarded as the gold standard for structural lung imaging but lacks functional information and involves significant radiation exposure. Lung magnetic resonance imaging (MRI) has historically been challenging due to its short T2 and low proton density. Hyperpolarised gas MRI is an emerging technique that is able to overcome these difficulties, permitting the functional and microstructural evaluation of the lung. Other novel imaging techniques such as fluorinated gas MRI, oxygen-enhanced MRI, Fourier decomposition MRI and phase-resolved functional lung imaging can also be used to interrogate lung function though they are currently at varying stages of development. This article provides a clinically focused review of these contrast and non-contrast MR imaging techniques and their current applications in lung disease.

Diagnostic Value of Liver Non-Contrast Perfusion in Prediction of Visceropathies (Sialadenitis and Hepatic Encephalopathy) in Patients with Diffuse Liver Diseases

The aim of this work is to evaluate diagnostic value of liver non-contrast perfusion in prediction of visceropathies (sialadenitis and hepatic encephalopathy) in patients with diffuse liver diseases (DLD). Clinical and laboratory data (including the Raitan test), results of MRI with non-contrast MR perfusion (ASL-perfusion) of the liver and brain MRI with assessment of the head and neck soft tissues were estimated in a group of patients with DLD. Potentials of assessment of ASL liver perfusion for hepatic encephalopathy and sialadenitis prediction are described in the article. Based on the clinical and laboratory data and results of histopathological analysis of salivary gland biopsies, it was established that sialadenitis in patients with DLD is the result of disturbance of macroorganism resistance; sialadenitis in this context is the inflammatory process of the gland with acinuses atrophy signs, in MRI it forms pictures of the gland enlargement without visible macrostructure changes. The study showed that the integrated approach to observation of patients with DLD (radiologist + gastroenterologist / infectious disease specialist + otorhinolaryngologist / dentist) helps correct of patient monitoring tactics timely and effective.

Evaluation of optic nerve by histogram analysis on MRI in patients with isolated optic neuritis

Objectives: We aimed to evaluate the Magnetic Resonance Imaging (MRI) histogram texture analyzis of the optic nerve by comparing patients of isolated optic neuritis with a healthy control group and to provide objective information without using contrast in the diagnosis of the disease. Methods: A total of 40 patients, including 20 patients with isolated optic neuritis (13 females, 7 males) and 20 healthy controls (11 females, 9 males), were included in the study. Non-contrast brain MR images of the patient and control groups were analyzed retrospectively. In the coronal T2-weighted MRI sequence of both groups, the Region of Interest (ROI) was placed in the extraocular anterior 1/3 of the optic nerve of both eyes. Numerical data were obtained using histogram analysis and the data were evaluated in the MATLAB program. The data were compared statistically. In addition, sensitivity and specificity were determined by Receiver Operating Characteristic (ROC) curve analysis. Results: As a result of histogram analysis, a significant difference was found between the mean values in the healthy and affected eye of the patients with isolated optic neuritis and the mean values of the control group (p &amp;lt; 0.05). A significant difference was found in standard deviation, minimum, maximum, median, variance values between both groups. ROC analysis was performed for mean value, AUC = 0.943 and when threshold value was selected as 354.258 Haunsfield Unit, two groups could be differentiated with 84.2% of sensitivity and 92.1% of specificity. We can say that patients with isolated optic neuritis also have histological effects on the clinically asymptomatic eye. Conclusions: Histogram analysis can be used in the diagnosis of the patients with isolated optic neuritis without the need to use contrast in their MRI. In addition, histological effect can be detected in the eye that does not show clinical symptoms with histogram analysis.

Building a comprehensive cardiovascular magnetic resonance exam on a commercial 0.55 T system: A pictorial essay on potential applications.

Contemporary advances in low-field magnetic resonance imaging systems can potentially widen access to cardiovascular magnetic resonance (CMR) imaging. We present our initial experience in building a comprehensive CMR protocol on a commercial 0.55 T system with a gradient performance of 26 mT/m amplitude and 45 T/m/s slew rate. To achieve sufficient image quality, we adapted standard imaging techniques when possible, and implemented compressed-sensing (CS) based techniques when needed in an effort to compensate for the inherently low signal-to-noise ratio at lower field strength. A prototype CMR exam was built on an 80 cm, ultra-wide bore commercial 0.55 T MR system. Implementation of all components aimed to overcome the inherently lower signal of low-field and the relatively longer echo and repetition times owing to the slower gradients. CS-based breath-held and real-time cine imaging was built utilizing high acceleration rates to meet nominal spatial and temporal resolution recommendations. Similarly, CS 2D phase-contrast cine was implemented for flow. Dark-blood turbo spin echo sequences with deep learning based denoising were implemented for morphology assessment. Magnetization-prepared single-shot myocardial mapping techniques incorporated additional source images. CS-based dynamic contrast-enhanced imaging was implemented for myocardial perfusion and 3D MR angiography. Non-contrast 3D MR angiography was built with electrocardiogram-triggered, navigator-gated magnetization-prepared methods. Late gadolinium enhanced (LGE) tissue characterization methods included breath-held segmented and free-breathing single-shot imaging with motion correction and averaging using an increased number of source images. Proof-of-concept was demonstrated through porcine infarct model, healthy volunteer, and patient scans. Reasonable image quality was demonstrated for cardiovascular structure, function, flow, and LGE assessment. Low-field afforded utilization of higher flip angles for cine and MR angiography. CS-based techniques were able to overcome gradient speed limitations and meet spatial and temporal resolution recommendations with imaging times comparable to higher performance scanners. Tissue mapping and perfusion imaging require further development. We implemented cardiac applications demonstrating the potential for comprehensive CMR on a novel commercial 0.55 T system. Further development and validation studies are needed before this technology can be applied clinically.

3D whole-heart noncontrast coronary MR angiography based on compressed SENSE technology: a comparative study of conventional SENSE sequence and coronary computed tomography angiography

ObjectiveThe relatively long scan time has hampered the clinical use of whole-heart noncontrast coronary magnetic resonance angiography (NCMRA). The compressed sensitivity encoding (SENSE) technique, also known as the CS technique, has been found to improve scan times. This study aimed to identify the optimal CS acceleration factor for NCMRA.MethodsThirty-six participants underwent four NCMRA sequences: three sequences using the CS technique with acceleration factors of 4, 5, and 6, and one sequence using the conventional SENSE technique with the acceleration factor of 2. Coronary computed tomography angiography (CCTA) was considered as a reference sequence. The acquisition times of the four NCMRA sequences were assessed. The correlation and agreement between the visible vessel lengths obtained via CCTA and NCMRA were also assessed. The image quality scores and contrast ratio (CR) of eight coronary artery segments from the four NCMRA sequences were quantitatively evaluated.ResultsThe mean acquisition time of the conventional SENSE was 343 s, while that of CS4, CS5, and CS6 was 269, 215, and 190 s, respectively. The visible vessel length from the CS4 sequence showed good correlation and agreement with CCTA. The image quality score and CR from the CS4 sequence were not statistically significantly different from those in the other groups (p > 0.05). Moreover, the image score and CR showed a decreasing trend with the increase in the CS factor.ConclusionsThe CS technique could significantly shorten the acquisition time of NCMRA. The CS sequence with an acceleration factor of 4 was generally acceptable for NCMRA in clinical settings to balance the image quality and acquisition time.

A Novel Approach to Vessel-Sparing Prostate Radiotherapy Using MR-Only Simulation and Non-Contrast MR Angiography: Vessel Delineation Feasibility and SBRT Dosimetric Analysis

<h3>Purpose/Objective(s)</h3> Erectile dysfunction is a common side effect of prostate cancer treatment, including prostate radiotherapy (RT). Vessel-sparing RT with avoidance of the internal pudendal artery (IPA) has shown promising rates of erectile function in non-randomized data. Implementation of vessel-sparing RT can be complicated by factors such as difficulty of MRI registration to planning CT and clinical desires to reduce routine use of IV contrast. We optimized a non-contrast MR angiography (ncMRA) sequence and compared IPA delineation on ncMRA with contrast MRA in a cohort of patients undergoing prostate stereotactic body RT (SBRT). We further performed dosimetric analysis on the IPAs. <h3>Materials/Methods</h3> Prostate cancer patients were prospectively enrolled on an IRB-approved MR imaging protocol. Treatment was with SBRT to a dose of 37.5 – 40 Gy in 5 fractions every other day. MR-only simulation was performed including MRA (2D T1w fast field echo (FFE) time-of-flight) and ncMRA (3D T1 FFE, 12 dynamics, temporal resolution = 14 seconds) sequences. Bilateral IPAs were delineated by a single blinded observer on MRA and ncMRA sequences. Analytical comparison between IPA contours on each patient was performed using mean distance to agreement (MDA), Dice similarity coefficient (DSC), and Jaccard index (JI). DSC and JI were also performed on IPA contour expansions of 2mm and 5mm. Dosimetry evaluated D50 and D05 on raw contours and 5mm expansion, and t-test compared dose on MRA and ncMRA. <h3>Results</h3> 10 patients were enrolled; 8 received 40 Gy, and 2 received 37.5 Gy. The median (range) analytical difference between IPA contours on MRA and ncMRA for MDA, DSC, and JI were 2.21 mm (0.99 – 4.16 mm), 0.54 (0.51 – 0.65), 0.37 (0.34 – 0.48), respectively. Using 2 mm contour expansion, DSC and JI were 0.69 (0.61 – 0.77) and 0.53 (0.44 – 0.63), while 5 mm expansion produced DSC and JI of 0.77 (0.69 – 0.85) and 0.62 (0.52 – 0.73). Dosimetrically, there was no difference in left and right IPA D50 or D05 between contours on MRA and ncMRA (Table). On 5mm expansion, the median (range) of D50 and D05 to IPA contours on ncMRA were 16.2 Gy (11.2 – 22.0 Gy) and 26.7 Gy (17.5 – 31.7 Gy). <h3>Conclusion</h3> This study found that delineation of IPAs using ncMRA was feasible and produced contours similar to those delineated on contrast MRA with no dosimetric differences. We feel that this agreement between imaging modalities demonstrates that ncMRA can be used alone for IPA delineation in vessel-sparing RT. Furthermore, the dosimetric findings of this study can serve as a baseline for expected IPA dose in prostate SBRT.

Extra-articular findings in patients with suspected labral tear and value of screening pelvis sequence

Objectives: There are multiple etiologies of hip pain, of which labral tear is one of the most common in young adults which may be difficult to distinguish on history and clinical examination. Labral tears can be diagnosed using high-resolution non-contrast magnetic resonance imaging (MRI) or MR arthrogram that involves imaging the concerned hip. At our institute, we perform an additional proton density fat saturated axial sequence of the pelvis to screen for alternative pathology and we investigate the value of this in this study. Material and Methods: A retrospective review of high-resolution non-arthrographic 3T MR of hips that were referred from young adult hip services with a history of hip or groin pain and the clinical suspicion of a labral tear over 2 years was performed. Those &lt;50 years were included in the study. Results: Of 648 patients with suspected labral tears, 18% showed evidence of extra-articular hip pathologies (sacroiliac joint pathology, iliopsoas pathology, and ischiofemoral impingement) on MRI. This study has shown that approximately one in five patients with a clinically suspected labral tear showed radiological evidence of extra-articular hip pathology (sacroiliac joint pathology, iliopsoas pathology, ischiofemoral impingement, and hamstring pathology). There is therefore the potential for misdiagnosis and increased morbidity if these alternative diagnoses were not appreciated. Conclusion: A high-resolution hip MRI protocol for suspected labral tears of the hip joint should include at least one sequence of the entire pelvis to evaluate for extra-articular findings.

Correlation between lumbar spinal canal magnetic resonance imaging grading systems and parameters in lumbar spinal canal compromise

BackgroundThere is a need to assess how commonly used classification systems of intervertebral disc degeneration reflect the compromise of neural elements. This study aims to explore the relationship between lumbar discs degenerative diseases using the Pfirrmann and the Combined Task Forces (CTF) of the North American Spine Society (NASS) grading systems as well as qualitative and quantitative grades of lumbar spinal stenosis. This retrospective cohort study included adult patients undergoing non-contrast MR imaging of lumbosacral spine. The radiological assessment included the Pfirrmann grading system, Van Rijn classification, Combined Task Force (CTF) classification, measurement of the cross-sectional area of the dural sac, mid-sagittal antero-posterior diameter of the thecal sac, the degree of dural sac compression at disc level, lateral recesses heights, and intervertebral foramina diameters. The degree of stenosis of the spinal canal and intervertebral foramina was assessed.ResultsOne hundred patients were included in the study. At all levels, Pfirrmann grades had a moderate, significant, positive correlation with the severity of stenosis of the central and lateral spinal canals as well as foraminal stenosis. The grades of lumbar spinal canal and foraminal stenosis had a significant positive correlation with degree of disc displacement as assessed by CTF classification and had a significant negative correlation with the quantitative lumbar spinal canal and foraminal measures.ConclusionsThere is a good correlation between Pfirrmann classification, CTF classification of NASS, qualitative grading and quantitative measures of lumbar spinal canal that reflects the severity of lumbar spinal canal stenosis and nerve root compression.

Postoperative Imaging of the Rotator Cuff: A Systematic Review and Meta-Analysis.

BACKGROUND. It is unclear which, MRI or ultrasound (US), is the most useful imaging tool to diagnose rotator cuff retears. OBJECTIVE. The objective of this study was to evaluate MRI and US in terms of diagnosing retear of a repaired rotator cuff tendon using a systematic review and meta-analysis. EVIDENCE ACQUISITION. A comprehensive literature search was performed on the main concepts of MRI (including noncontrast MRI and MR arthrography), US, and rotator cuff repairs. Inclusion criteria consisted of original research studies that assessed the diagnostic accuracy of MRI and US (index tests) for the diagnosis of rotator cuff tendon retear after prior rotator cuff repair using surgical findings as the reference standard. QUADAS-2 was used to assess methodologic quality. Meta-analyses were performed to compare MRI and US studies in the diagnosis of all retears and of full-thickness retears. Study variation was analyzed using the Cochran Q test and I2 statistic. EVIDENCE SYNTHESIS. Eight studies (MRI, n = 6; US, n = 2) satisfied inclusion and exclusion criteria, consisting of 304 total patients (MRI, n = 221; US, n = 83) and 309 shoulders (MRI, n = 226; US, n = 83). Years of publication ranged from 1993 to 2006 for the MRI studies and from 2003 to 2018 for the US studies. Two studies had high risk of bias in terms of applicability to clinical practice because of patient selection. Five studies had potential risk of bias in two categories, whereas two had potential risk of bias in three categories. For all retears, mean sensitivity and specificity for MRI were 81.4% (95% CI, 73.3-87.5%) and 82.6% (95% CI, 76.3-87.5%) and 83.7% (95% CI, 67.4-92.7%) and 90.7% (95% CI, 73.6-97.1%) for US. For full-thickness retears, mean sensitivity and specificity for MRI were 85.9% (95% CI, 80.2-90.2%) and 89.1% (95% CI, 84.6-92.4%) and 89.7% (95% CI, 75.6-96.1%) and 91.0% (95% CI, 75.5-97.1%) for US. There was no significant difference in terms of sensitivity or specificity for either comparison (p = .28-.76). CONCLUSION. Our analyses revealed no significant difference between US and MRI for the diagnosis of rotator cuff tendon tears after prior cuff repair. CLINICAL IMPACT. Either MRI or US can be considered a first-line imaging option to assess suspected rotator cuff retear after prior repair.

Diffusion-weighted magnetic resonance imaging of abdominal tuberculosis: a new take on an old disease.

Abdominal tuberculosis is a major cause of mortality and morbidity in developing countries also re-emerging in western world due to the AIDS epidemic and population migration. Large proportion of the patients are young and hence radiation exposure is of concern. In addition, in some patients, contrast may be contraindicated or repeat studies may be required, where MR especially DWI may be useful. The aim of the study is to describe MRI features in abdominal tuberculosis including DWI in the involved bowel, lymphadenopathy, omental, and peritoneal thickening. Nodes being especially easy to appreciate on DWI, thus DWI in conjunction with routine noncontrast MR sequence can be useful technique to identify abdominal tubercular lesions in patients with contraindication to contrast.

Role of diffusion-weighted imaging in carotid plaque vulnerability assessment

BackgroundMR plaque imaging is a valuable tool in characterizing carotid atherosclerotic plaque and identifying high-risk features. There are limited data on the role of the widely available single-shot diffusion-weighted imaging (DWI) in plaque characterization along with histological correlation. This study aimed to correlate the plaque characteristics identified by MR imaging in vivo at the level of maximum stenosis with histological plaque characteristics in the postoperative specimen.MethodsPatients who underwent carotid endarterectomy in a tertiary care center during one and half years were prospectively recruited for non-contrast MR carotid plaque imaging (including single-shot EPI-DWI sequence) in a 3 Tesla MRI using a dedicated carotid coil. An experienced radiologist correlated DWI sequence findings with histopathology of postsurgical sections to confirm the high-risk features.ResultsTwenty-three patients (mean age 66.1 years ± SD 6.25) were evaluated, of which 65% were males and 96% were symptomatic. Apparent diffusion coefficient (ADC) values in location of plaques could differentiate histopathological unstable from stable plaques (0.83 × 10–3 mm2/s vs 1.7 × 10–3 mm2/s; p 0.001), with a sensitivity and specificity of 75% and 79%, respectively, at an ADC cutoff of 1.24 × 10–3 mm2/s. Plaques with and without lipid-rich necrotic core (0.86 × 10–3 mm2/s vs 1.44 × 10–3 mm2/s; p = 0.042) as well as intraplaque hemorrhage could be differentiated (0.751 × 10–3 mm2/s vs 1.352 × 10–3 mm2/s; p 0.037) using the apparent diffusion coefficients.ConclusionThe widely available single-shot EPI-DWI in assessing plaque characteristics in carotid stenosis is promising and correlated with histopathological features. Diffusion-weighted imaging will be a helpful adjunct in patients when contrast administration is intolerable.

Using Magnetic Resonance Liver Non-Contrast Perfusion in Patients with Diffuse Liver Diseases

The aim of this work is to evaluate possibilities of MR liver non-contrast perfusion in patients with diffuse liver diseases (DLD). Laboratory data, results of ultrasound examination with doppler ultrasonography of liver vessels, results of MRI with non-contrast MR perfusion (ASL-perfusion) of the liver was estimated in a group of patients with DLD. Potentials of assessment of ASL liver perfusion for clinical form prediction are described in the article. Potentials of using the assessment of ASL liver perfusion for information about a liver blood flow type and process activity indicators by blood chemistry are also described. It was established, that ASL MR of the liver is recommended to use in patients with diffuse liver diseases who admitted to a hospital, then in 1 month (in case of hypo/hyperperfusion) or in 6 months (in case of normal perfusion).