Contrast-enhanced MRI Studies Research Articles

Optimizing timing for quantification of intracranial aneurysm enhancement: a multi-phase contrast-enhanced vessel wall MRI study.

Aneurysm wall enhancement (AWE) on high-resolution contrast-enhanced vessel wall MRI (VWMRI) is an emerging biomarker for intracranial aneurysms (IAs) stability. Quantification methods of AWE in the literature, however, are variable. We aimed to determine the optimal post-contrast timing to quantify AWE in both saccular and fusiform IAs. Consecutive patients with unruptured IAs were prospectively recruited. VWMRI was acquired on 1 pre-contrast and 4 consecutive post-contrast phases (each phase was 9 min). Signal intensity values of cerebrospinal fluid (CSF) and aneurysm wall on pre- and 4 post-contrast phases were measured to determine the aneurysm wall enhancement index (WEI). AWE was also qualitatively analyzed on post-contrast images using previous grading criteria. The dynamic changes of AWE grade and WEI were analyzed for both saccular and fusiform IAs. Thirty-four patients with 42 IAs (27 saccular IAs and 15 fusiform IAs) were included. The changes in AWE grade occurred in 8 (30%) saccular IAs and 6 (40%) in fusiform IAs during the 4 post-contrast phases. The WEI of fusiform IAs decreased 22.0% over time after contrast enhancement (p = 0.009), while the WEI of saccular IAs kept constant during the 4 post-contrast phases (p > 0.05). When performing quantitative analysis of AWE, acquiring post-contrast VWMRI immediately after contrast injection achieves the strongest AWE for fusiform IAs. While the AWE degree is stable for 36 min after contrast injection for saccular IAs. The standardization of imaging protocols and analysis methods for AWE will be helpful for imaging surveillance and further treatment decisions of patients with unruptured IAs. Imaging protocols and measurements of intracranial aneurysm wall enhancement are reported heterogeneously. Aneurysm wall enhancement for fusiform intracranial aneurysms (IAs) is strongest immediately post-contrast, and stable for 36 min for saccular IAs. Future multi-center studies should investigate aneurysm wall enhancement as an emerging marker of aneurysm growth and rupture.

Radiation source personalization for nanoparticle-enhanced radiotherapy using dynamic contrast-enhanced MRI in the treatment planning process

Nanoparticle-enhanced radiotherapy offers the potential to selectively increase the radiation dose imparted to the tumor while at the same time sparing the healthy structures around it. Among the recommendations of an interdisciplinary group for the clinical translation of this treatment modality, is the developing of methods to quantify the effects that the nanoparticle concentration has on the radiation dosimetry and incorporate these effects into the treatment planning process. In this work, using Monte Carlo simulations and dynamic contrast-enhanced MRI images, treatment plans for nanoparticle-enhanced radiotherapy are calculated in order to evaluate the effects that realistic distributions of the nanoparticles have on the resultant plans and to devise treatment strategies to account for these effects, including the selection of the proper x-ray source configuration in terms of energy and collimation. Dynamic contrast-enhanced MRI studies were obtained for two treatment sites, namely brain and breast. A model to convert the MRI signal to contrast agent concentration was applied to each set of images. Two treatment modalities, 3D conformal radiotherapy and Stereotactic Body Radiation Therapy, were evaluated at three different x-ray spectra, namely 6 MV from a linear accelerator, 110 kVp and 220 kVp from a tungsten target. For the breast patient, as the nanoparticle distribution varies markedly with time, the treatment plans were obtained at two different times after administration. It was determined that maximum doses to the healthy structures around the tumor are mostly determined by the minimum nanoparticle concentration in the tumor. The presence of highly hypoxic or necrotic tissue, which fails to accumulate the nanoparticles, or leakage of the contrast agent into the surrounding healthy tissue, make irradiation with conventional conformal radiotherapy unfeasible for kilovoltage beam energies, as the uniform beam apertures lack the ability to compensate for the non-uniform distribution of the nanoparticles. Therefore, proper quantification of the nanoparticle distribution not only in the target volume but also in the surrounding tissues and structures is crucial for the proper planning of nanoparticle-enhanced radiotherapy and a treatment delivery with a high-degree of freedom, such as small-field stereotactic body radiotherapy, should be the method of choice for this treatment modality.

Automatic Protocolling of Non-contrast Musculoskeletal MRIs Does Not Result in Increase in Patient Recall Rates for Contrast-Enhanced Studies

IntroductionPhysicians spend large amounts of time on protocolling imaging studies, limiting their time spent on other essential clinical tasks. Most musculoskeletal (MSK) MRI studies are performed for the evaluation of joint pain and internal derangements and usually require no intravenous contrast. Contrast-enhanced MRI studies are performed for the evaluation of infection, suspected or established tumor, and rheumatological conditions. Protocolling all MSK MRI studies takes time away from other important tasks during the workday. Routine joint MRI scans have established set of sequences, and thus, could be scheduled and performed without special protocols by the radiologists. In a large tertiary care center like ours with multiple MRI magnets, we set up a process of automated protocoling and scheduling of non-contrast joint MRI scans ordered by referring doctors. This project's purpose was to assess the effect of this newly established process of ‘automatic protocoling and scheduling’ of MSK MRI scans on the rate of overlooked MRI exams that may have required contrast examinations, and on the patient recall-rate to obtain follow up post-contrast sequences for further diagnostic characterization. MethodsAll musculoskeletal reports of MRIs during the last two months of the years before and after the implementation of automatic protocolling (intervention) were searched for the presence of indications related to neoplasms, infections, and rheumatological conditions. For each of the three disease categories, we determined the number of MRIs obtained with and without contrast before and after the intervention. For each matching study obtained without contrast, the patient chart was reviewed for contraindications to contrast, positive final diagnosis, whether interpreting radiologist mentioned the exam being limited by lack of contrast, and recommendations for a follow-up contrast enhanced study. ResultsA total of 846 musculoskeletal MRIs were performed prior to intervention and 822 MRIs were performed afterwards. Overall, 25% of the studies were performed without contrast prior to the intervention, and 31% of studies were performed without contrast afterwards (Chi square 0.07, p-value 0.79). No report contained a recommendation for contrast enhanced follow-up study before or after the intervention. DiscussionAutomatic protocolling of routine MSK non-contrast MRI studies resulted in statistically insignificant, minimal increase in the overall number of non-contrast enhanced studies obtained for work up of neoplasms, infections, and rheumatological conditions. There was no increase in patient recall rate for additional post contrast sequences and the new process resulted in time savings to fellows and other physicians, being not distracted from other important tasks.

Correlation of Perfusion Metrics with Ki-67 Proliferation Index and Axillary Involvement as a Prognostic Marker in Breast Carcinoma Cases: A Dynamic Contrast-Enhanced Perfusion MRI Study.

Our study aims to reveal clinically helpful prognostic markers using quantitative radiologic data from perfusion magnetic resonance imaging for patients with locally advanced carcinoma, using the Ki-67 index as a surrogate. Patients who received a breast cancer diagnosis and had undergone dynamic contrast-enhanced magnetic resonance imaging of the breast for pretreatment evaluation and follow-up were searched retrospectively. We evaluated the MRI studies for perfusion parameters and various categories and compared them to the Ki-67 index. Axillary involvement was categorized as low (N0-N1) or high (N2-N3) according to clinical stage. A total sum of 60 patients' data was included in this study. Perfusion parameters and Ki-67 showed a significant correlation with the transfer constant (Ktrans) (ρ = 0.554 p = 0.00), reverse transfer constant (Kep) (ρ = 0.454 p = 0.00), and initial area under the gadolinium curve (IAUGC) (ρ = 0.619 p = 0.00). The IAUGC was also significantly different between axillary stage groups (Z = 2.478 p = 0.013). Outside of our primary hypothesis, associations between axillary stage and contrast enhancement (x2 = 8.023 p = 0.046) and filling patterns (x2 = 8.751 p = 0.013) were detected. In conclusion, these parameters are potential prognostic markers in patients with moderate Ki-67 indices, such as those in our study group. The relationship between axillary status and perfusion parameters also has the potential to determine patients who would benefit from limited axillary dissection.

Alteration in Microcirculation With Osteonecrosis of the Femoral Head: A Study of Dynamic Contrast-Enhanced MRI.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is commonly used in clinical practice to detect tumor blood supply, and it has recently been applied to assess skeletal vasculature. In this study, we retrospectively analyzed DCE-MRI data from 37 patients with osteonecrosis of the femoral head to evaluate alterations in microvascular circulation of the femoral head. Time-intensity curves (TICs) in the region of interest were classified into different lesion stages. In the greater trochanter area, extracellular space volume per unit volume of tissue was significantly higher in Association Research Circulation Osseous (ARCO) stage III than in ARCO stage II (P<.05 and power ≥ 0.8), while other parameters showed no statistical difference (P>.05 and/or power < 0.8). In the necrotic area, contrast enhancement ratio and maximum slope of increase were significantly lower in ARCO stage III than in ARCO stage II (P<.05 and power ≥ 0.8), while other parameters showed no statistical difference (P>.05 and/or power < 0.8). In the repair reaction area, all parameters were significantly higher in ARCO stage III than in ARCO stage II (P<.05 and power ≥ 0.8). TIC classification showed that the greater trochanter area mainly exhibited type C (plateau type), the necrotic area mainly exhibited type B (out-flow type), and the repair reaction area mainly exhibited type A (inflow type). We believe that the exchange capacity of the vessels has a much greater impact on femoral head necrosis than the number of vessels, while the generation of the repair area greatly affects the prognosis of femoral head necrosis. These findings suggest that DCE-MRI can provide a good assessment of osteonecrosis of the femoral head perfusion and can serve as a new reference for clinical treatment decisions. [Orthopedics. 2024;47(2):e73-e78.].

Relationship Between Patient-Friendly Audiovisual Systems and MRI Contrast Agent to Adverse Reactions.

Patient-friendly audiovisual (AV) systems in head MRI examinations can potentially reduce patient anxiety and contrast-enhanced MRI (CE-MRI) adverse reactions to gadolinium. To evaluate whether a patient-friendly AV system reduces the rate of adverse reactions to gadolinium-based contrast agents. Retrospective. Four thousand eight hundred thirty-two outpatients (2462 female) attending for clinical CE-MRI studies. (Gadoteridol: 1971, Meglumine gadoterate: 2733, Gadobutrol: 128.) FIELD STRENGTH/SEQUENCE: Routine CE-MRI of head and neck using a 1.5 T or 3 T scanner with or without a patient-friendly AV system. One thousand one hundred fifty-nine patients were scanned on MRI machines equipped with patient-friendly AV systems (AV group) and 3673 on MRI machines without AV systems (control group). Adverse reaction rate and symptoms were reviewed by referring to the system database and electronic medical records and compared between the two groups. Adverse reactions were defined as physiological reactions, such as vomiting and allergic-like reactions, such as urticaria, occurring within 1 hour of contrast injection. We compare patient backgrounds, adverse reaction rate, adverse reactions symptoms and the severity between the two groups. Adverse reaction rate with and without a patient-friendly AV system were compared using Fisher's exact test. The relationship between patient-friendly AV systems and the occurrence of adverse reactions was evaluated with logistic regression. Statistical significance was set at P < 0.05. Of the 4832 patients enrolled, 65 (1.35%) experienced adverse reactions. The most common adverse reactions in both groups were urticaria and pruritus. Adverse reaction rate was significantly lower in the AV group than in the control group (0.7% vs. 1.6%). No significant difference was observed in the severity (P = 1.000) of adverse reactions and symptoms (allergic-like reaction: P = 0.08, physiologic reaction: P = 1.000) between the two groups. The patient-friendly AV system significantly reduce adverse reaction occurrence to gadolinium-based contrast agents. 4 TECHNICAL EFFICACY: Stage 1.

Augmenting care in hepatocellular carcinoma with artificial intelligence

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide and prognosis remains poor. The recent paradigm shifts in management algorithms of such patients have resulted in unique challenges in the early identification of HCC, prognosis, surgical outcomes, prioritization of potential transplant recipients, donor-recipient matching, and so on. In recent years, advancements in artificial intelligence (AI) capabilities have shown potential in HCC treatment. In this narrative review, we outline first the different types of AI models that are applied in clinical practice and then focus on the frontiers of AI research in the diagnosis, prognostication, and treatment of HCC, particularly in classification of indeterminate liver lesions, tumor staging, survival prediction, improving equity in transplant recipient selection, prediction of treatment response and prognosis. We show that US coupled with AI-driven predictive models can provide accurate noninvasive screening tools for early disease. While AI models applied to contrast-enhanced CT, MRI and PET studies may appear to have limited clinical utility in disease diagnosis and differentials, owing to their accuracy, we highlighted the importance of such models in predicting pathological findings preoperatively. Despite the availability of many accurate, sensitive, and specific AI algorithms that outperform traditional scoring systems, they have not been widely used in clinical practice. The challenges in AI application, including distributional shift and imbalanced data, lack of standardization, and the ‘black box’ phenomenon, are addressed here. The importance of AI in the future of HCC makes it important for clinicians to have a good understanding of different AI techniques, their benefits, and potential pitfalls.

Role of MRI in evaluation and characterization of neoplastic and nonneoplastic cardiac masses

BackgroundThe overall frequency of cardiac tumors is quite low, with an estimated cumulative prevalence of 0.002–0.3% at autopsy, however, they represent an important group of cardiovascular abnormalities as the early and accurate diagnosis maybe curative and sometimes avoids unnecessary surgery.Aim and objectivesThe aim of this study was to evaluate the efficacy of MRI, in diagnosis, evaluation, and characterization of cardiac neoplasms, as identification and differentiation between the cardiac masses are of extreme importance to develop exquisite better therapeutic planning and positive prognostic results.Patients and methodsThis study is a prospective one that was conducted on 27 patients who were diagnosed to have cardiac masses by echocardiography or other imaging modalities. Contrast-enhanced MRI was done on closed Siemens MR Systems operating at 1.5 T in National Heart Institute in Giza. The study was performed after approval of the Ethical Committee of Scientific Research. Evaluation of cardiac masses was analyzed, regarding the involved chambers, pericardial violation, morphological characters, as well as their pattern of enhancement at contrast-enhanced cardiac MRI studies, aiming at characterization of different cardiac masses on MRI diagnostic bases.ResultsIn our study, we diagnosed 85.2% (23/27) of the cases as benign-looking lesions (including both true and pseudotumors), while 14.8% (4/27) as malignant-looking lesions. A statistical significant difference was noted, regarding the differentiation between the benign and the malignant lesions regarding the size, marginal outline, pattern of growth, and pericardial affection, either infiltration or effusion. As regards the pericardial affection, none of the benign lesions showed pericardial infiltration compared with 50% (2/4) of the malignant lesions that showed pericardial infiltration with a statistically significant P value of 0.017.ConclusionCardiac magnetic resonance imaging (CMR) has a great role in evaluation of the cardiac masses by its powerful assessment of the anatomical and soft-tissue characterization of the masses, as well as their functional impact, and so it allows the differentiation between neoplastic and nonneoplastic masses, as well as between malignant and benign masses.

Multiple Sclerosis-Minimizing Errors in Radiological Diagnosis.

Multiple sclerosis is a chronic demyelinating disorder with a myriad of imaging and clinical features that overlap with number of other neurological conditions. Incorrect diagnosis poses a significant risk to patients, it may lead to delays in management, increased morbidity, and also adds to the financial cost. The aim of this study was to highlight strategies for the efficient differentiation of multiple sclerosis from other diseases which may masquerade as MS clinico-radiologically. A systematic literature review was conducted through online databases including PubMed and Medline. Relevant publications on radiological aspects of multiple sclerosis, white matter diseases and mimickers of Multiple sclerosis were included in the analysis. Common mimickers of MS include small vessel disease, acute disseminated encephalomyelitis, neuromyelitis optica, anti-MOG encephalomyelitis, vasculitis, and CADASIL. Contrast-enhanced MRI study performed using MS protocol on high strength MRI system evaluated following a structured protocol along with clinical correlation is effective in differentiating MS from its mimickers. Contrast-enhanced MRI performed on a high strength scanner using MS protocol with structured protocol for evaluation along, with a better collaboration between radiologists and clinicians may help in minimizing errors in diagnosis of multiple sclerosis.

Constrained generative adversarial network ensembles for sharable synthetic medical images.

Purpose: Sharing medical images between institutions, or even inside the same institution, is restricted by various laws and regulations; research projects requiring large datasets may suffer as a result. These limitations might be addressed by an abundant supply of synthetic data that (1)are representative (i.e., the synthetic data could produce comparable research results as the original data) and (2)do not closely resemble the original images (i.e., patient privacy is protected). We introduce a framework that generates data with these requirements leveraging generative adversarial network (GAN) ensembles in a controlled fashion. Approach: To this end, an adaptive ensemble scaling strategy with the objective of representativeness is defined. A sampled Fréchet distance-based constraint was then created to eliminate poorly converged candidates. Finally, a mutual information-based validation metric was embedded into the framework to confirm there are visual differences between the original and the generated synthetic images. Results: The applicability of the solution is demonstrated with a case study for generating three-dimensional brain metastasis (BM) from T1-weighted contrast-enhanced MRI studies. A previously published BM detection system was reported to produce 9.12 false-positives at 90% detection sensitivity based on the original data. By using the synthetic data generated with the proposed framework, the system produced 9.53 false-positives at the same sensitivity level. Conclusions: Achieving comparable algorithm performance relying solely on synthetic data unveils a significant potential to eliminate/reduce patient privacy concerns when sharing data in medical imaging.

Meningeal blood-brain barrier disruption in acute traumatic brain injury.

The meninges serve as a functional barrier surrounding the brain, critical to the immune response, and can be compromised following head trauma. Meningeal enhancement can be detected on contrast-enhanced MRI in patients presenting with acute traumatic brain injury, even when head CT is negative. Following head trauma, gadolinium-based contrast appears to extravasate from the vasculature, enhancing the dura within minutes, and later permeates the subarachnoid space. The aims of this study were to characterize the initial kinetics of the uptake of contrast agent after injury and the delayed redistribution of contrast enhancement in the subarachnoid space in hyperacute patients. Neuroimaging was obtained prospectively in two large ongoing observational studies of patients aged 18 years or older presenting to the emergency department with suspected acute head injury. Dynamic contrast-enhanced MRI studies in a cohort of consecutively enrolling patients with mild traumatic brain injury (n = 36) determined that the kinetic half-life of dural-related meningeal enhancement was 1.3 ± 0.6 min (95% enhancement within 6 min). The extravasation of contrast into the subarachnoid space was investigated in a cohort of CT negative mild traumatic brain injury patients initially imaged within 6 h of injury (hyperacute) who subsequently underwent a delayed MRI, with no additional contrast administration, several hours after the initial MRI. Of the 32 patients with delayed post-contrast imaging, 18 (56%) had conspicuous expansion of the contrast enhancement into the subarachnoid space, predominantly along the falx and superior sagittal sinus. Patients negative for traumatic meningeal enhancement on initial hyperacute MRI continued to have no evidence of meningeal enhancement on the delayed MRI. These studies demonstrate that (i) the initial enhancement of the traumatically injured meninges occurs within minutes of contrast injection, suggesting highly permeable meningeal vasculature, and that (ii) contrast in the meninges redistributes within the subarachnoid space over the period of hours, suggesting a compromise in the blood-brain and/or blood-cerebrospinal barriers. Data from the parent study indicate that up to one in two patients with mild traumatic brain injury have traumatic brain injury on acute (<48 h) MRI, with a higher prevalence seen in patients with moderate or severe traumatic brain injury. The current study's findings of traumatic meningeal enhancement and the subsequent delayed extravasation of contrast into the subarachnoid spaces indicate that a substantial percentage of patients with even mild traumatic brain injury may have a transient disruption in barriers separating the vasculature from the brain.

MR guided high intensity focused ultrasound (MRgFUS) for the treatment of oligometastatic prostate cancer bone metastasis.

e17600 Background: With improvements in diagnostic modalities such as functional imaging, oligometastatic prostate cancer is being diagnosed with greater frequency than ever before. Our aim was to determine MRgFUS ability to downstage patients with oligometastatic bone disease with single session of non-invasive metastasis-directed therapy. Methods: The study was designed with intention-to-treat metastatic bone lesions. Patients were enrolled if they had accessible bone metastasis and could safely undergo MRgFUS (InSightec, Israel). Baseline measurable characteristics included dynamic contrast enhanced MRI study (DCE; Gd-BOPTA, Bracco; GE 750 3T magnet) with semiquantitative perfusion analysis, PSA level (ng/ml) and choline PET (SUV). Measurable variables were obtained at treatment time, 3 months, 12 months and 24 months follow-up. Results: 18 patients fulfilled the inclusion criteria and safely underwent MRgFUS procedure of metastatic bone ablations. Lesions were located in the pelvis (11), scapula (3) and long bones (4). At baseline all lesions showed a significant DCE perfusion (highly vascular) with mean perfusion reduction of 88% at 3 months follow-up (CI: 100-50; p &lt; 0.001) stable at subsequent follow-up scans. Similarly PSA levels decreased from a mean baseline of 19 (ng/ml) to 7.1, 2.9 and 2.1, at 3-12 and 24 moths respectively. SUV values showed similar trend with reduction from baseline (mean 8.9 to 3.0, 2.3 and 1.7: p &lt; 0.001). In all patients single MRgFUS session was appropriate without any major or minor adverse events reported. Conclusions: MRgFUS is a totally non-invasive procedure that can obtain complete bone ablation in patients with oligometastatic prostate disease. The technique features a radiation-free approach that can be of incremental value in long-survivor subset on oncological patients, significantly reducing risk of toxic effects. Concurrent chemo regimen is not a contraindication.

Validation of Region of Interest Measurements for the Objective Assessment of Post-Contrast Enhancement of Renal Lesions on MRI.

The aim of this study was to validate the use of region of interest (ROI) measurements in MRI to objectively assess for enhancement in suspected solid renal masses and to determine a minimum threshold value for true enhancement. Contrast-enhanced renal MRI studies performed between January 2015 and December 2017 for patients with a known renal mass who had subsequent biopsy, or partial/radical nephrectomy were included. Two body imaging fellows independently measured the mean ROI values of renal masses, normal renal parenchyma, the ipsilateral psoas muscle and external air on the pre- and post-contrast sequences. The absolute and percentage changes in the mean ROI values were calculated. The readers were blinded to the pathology results. 104 patients were included in this study (mean age of 65 years; 58 males and 46 females). 74 patients (71%) had a diagnosis of renal cell carcinoma (RCC). Pathology showed clear-cell RCC in 55%, papillary RCC in 22%, and other RCC subtypes in 23%. There were 30 non-RCC renal lesions (29%), including oncocytoma, renal papillary adenoma, and renal metastasis.The minimum percentage change in ROI values in the pre- versus post-contrast images for all pathology-proven RCCs was 23% (range: 23-437%, mean: 143%); this represents relative enhancement and was referred to as the Signal Intensity Index (SII). The percentage change for normal renal parenchyma ranged from 32-317%. The maximum percentage change in ROI values for pathology proven renal cysts was 13% (range: -5-13%, mean: 3.5%). There was excellent inter observer agreement between the two readers [Intra-class correlation coefficient (r) 0.81]. The percentage change in ROI values (SII) can be a helpful tool in the objective assessment of true enhancement of renal masses and can supplement subtraction images. The minimum threshold for enhancement in our study was 23%. Enhancement of a renal lesion can be determined using the objective tool of ROI measurements in the pre- and post-contrast MR images with a percentage change of 20% or above indicating enhancement. This is an additional objective tool, which in conjunction with the subtraction images may improve detection and appropriate diagnosis of renal lesions. It could also be helpful in cases where the subtraction images are degraded by motion artefact.

Evaluation of suspected musculoskeletal infection in children over 2years of age using only fluid-sensitive sequences at MRI.

This study was conducted in order to evaluate whether an MRI protocol with only fluid-sensitive sequences can be used to evaluate for musculoskeletal (MSK) infection of the pelvis and limbs in children. This retrospective study analyzed 90 contrast-enhanced (CE) MRI studies from 88 consecutive patients (52 boys and 36 girls; mean age 9 ± 4.3years; range 2-17) that were performed for the clinical suspicion of MSK infection. Two radiologists reviewed each study twice. The initial study review included only the fluid-sensitive sequences (fluid-sensitive study); the second review, performed at least 1month later, included all sequences of the contrast-enhanced study (CE study). At each review, anatomic sites of abnormal signal and overall suspicion for infection were recorded. Cohen's kappa and percent agreement were performed to compare agreement between readers, types of studies, and clinical diagnoses. Interreader agreement for both types of studies had kappa values between 0.86 and 1. For the assessment of MSK infection, the fluid-sensitive study had 100% sensitivity and 61.3% specificity, with 84.8% interreader agreement; and the CE study had 100% sensitivity and 71.0% specificity, with 88.6% interreader agreement. All cases of septic arthritis (13 cases) and osteomyelitis (25 cases) were identified as possible infection or infection until proven otherwise (negative predictive value 100%) with 100% interreader agreement on fluid-sensitive sequences. An abbreviated MRI study using only fluid-sensitive sequences has the same high degree of sensitivity as a CE study to identify MSK infection in children and could be used to exclude septic arthritis and osteomyelitis. • MRI with only fluid-sensitive sequences can be used to evaluate for musculoskeletal infection in children.

Headache - an Update 2018

Epidemiological studies have shown a clear correlation between migraine and vascular disease in more and more patients. Pathophysiological studies show the relevance of the hypothalamus in the generation of migraine attacks. Glutamate seems to play an important role here. New contrast-enhanced MRI studies support the assumption that the blood-brain barrier remains intact during migraine attacks. The selection of a triptan still remains unique. Neurostimulation has also been included in the acute treatment of migraine. Monoclonal humanized antibodies against CGRP (calcitonin gene-related peptides) and a fully human antibody against the CGRP receptor are effective in the prophylaxis of both episodic and chronic migraine. Tricyclic antidepressants showed efficacy in tension-type headache and is superior compared to SSRIs (selective serotonin reuptake inhibitors). Electronic diaries can reduce the risk of relapse after a medication break in the event of overuse of headache medication. In patients with episodic cluster headache, successful transient therapy with transcutaneous stimulation of the vagus nerve may be required. In trigeminal neuralgia, a significant comorbidity with depression and anxiety disorders was found.

Role of DW-MRI and ADC value in monitoring therapy of head and neck squamous cell carcinoma

AimTo evaluate role of DW-MRI and ADC value in monitoring therapy of head and neck squamous cell carcinoma (HNSCC). Patients & methodsFourty patients with head and neck squamous cell carcinoma, age ranged from 40 to 68 years, 30 patients were male while 10 were female. Pre-treatment examinations included contrast-enhanced CT, endoscopic biopsy & MRI study. Pre-treatment 1st DW-MRI imaging within 10 days before treatment (ADC1), 2nd imaging 3 weeks after start of treatment (ADC2) and 3rd after 6–8 weeks from end of treatment. ResultsSignificant changes between mean ADC value of 40 primary lesions & 22 metastatic LNs, noted at ADC1 and ADC2, indicating high ability of DW-MRI to detect early changes occur after beginning of treatment. Relationship between pretreatment ADC value and prediction of early treatment response revealed 76.9% sensitivity, 71.4% specificity, 83.3% PPV and 62.5% NPV. ROC curve for fractional ADC value change (ADC2 - ADC1) from 40 lesions primary tumors provided best discriminatory accuracy (AUC = 0.85 ± 0.09) in distinguishing between responders and non-responders with 92.3% sensitivity, 85.7% specificity, 92.9% PPV and 85.7% NPV. ConclusionIntra treatment ADC value can be used as a marker for prediction and monitoring therapy response for HNSCC.

MRI gadolinium dosing on basis of blood volume.

Gadolinium-based contrast agents (GBCAs) for MRI are generally administrated in direct relationship to body weight. Instead, we propose a model for GBCA dosing on the basis of blood volume. The new method was tested by exploring the associations between MRI T1 mapping indices and weight in the MESA (Multi-Ethnic Study of Atherosclerosis. Empirically derived methods based on sex and body habitus were used to calculate blood volumes. GBCA dose (in mL) in blood (in L) was calculated as the injected volume divided by the blood volume (i.e., DBV). Of the 1219 participants with cardiac MRI T1 mapping, 845 studies had standard dose of 0.15 mmol/kg (cohort 1) and 166 studies had 30 mL of GBCA regardless of weight (cohort 2). We also created a specific cohort with similar DBV (N = 357; cohort 3). Postcontrast blood relaxation rate R1blood and DBV were significantly correlated (R = 0.641; P < 0.001). R1blood was significantly associated with weight in cohort 1 and 2, but the correlation coefficient was positive for cohort 1 and negative for cohort 2, indicating GBCA overdosing in cohort 1 and underdosing in cohort 2 in heavy relative to lean subjects. R1blood was not associated with weight in cohort 3. Simulated results demonstrated that less contrast should be administrated for heavy subjects compared to the conventional weight-based dose. GBCA dosing on the basis of blood volume could improve the efficacy and safety of contrast-enhanced MRI studies. This method could be implemented to standardize dose and augment precision in study comparisons.

Can diffusion-weighted MRI replace conventional contrast enhanced MRI in the differentiation between benign and malignant pancreatic masses?

PurposeTo evaluate the role of diffusion weighted MRI (DW MRI) in the differentiating between benign and malignant pancreatic masses. Patients and MethodsSixty patients (36 men, mean age, 62 years; range, 48–72 years], 24 women (mean age, 64 years; range, 54–69 years] suspected to have solid pancreatic masses were examined by conventional and DWI. None of our patients had a history of pancreatic disease. DWI of the pancreas was performed in addition to the routine liver MR. Final diagnosis was obtained by diagnostic biopsy, lab. data and follow up. Results38 patients had a benign lesion and 22 patients had a malignant lesion. Using DWI, 36 cases were diagnosed to have benign lesions and 24 cases were diagnosed to have malignant lesions. There were two false positive cases due to low ADC value. The mean ADC values of malignant lesions were lower compared with benign lesion. The mean ADC value for malignant lesions was 1.1 +/− 0.201 × 10−3 mm2/sec, and for benign lesions it was 1.6 + l − 0.121 × 10−3 mm2/sec. ConclusionDWI and ADC values can help differentiate between benign and malignant pancreatic masses. Also DWI can be used for investigating patients for whom contrast-enhanced CT or MRI studies are contraindicated.

Kopfschmerzen – Update 2018

Die Kopfschmerzforschung macht Fortschritte. Dies zeigt sich an der großen Zahl von Publikationen zur Epidemiologie, Pathophysiologie, Akuttherapie und Prophylaxe von Kopfschmerzen. Die vorliegende Übersicht referiert die wichtigsten Studien zu Kopfschmerzen aus dem Zeitraum 2017 bis Juni 2018. Die Auswahl der referierten Studien ist subjektiv und erfolgte nach der Einschätzung der Autoren.

Dynamic contrast-enhanced MRI of orbital and anterior visual pathway lesions

PurposeThe accurate diagnosis of orbital and anterior visual pathway lesions has clinical significance. We determined whether dynamic contrast-enhanced MRI could differentiate benign from malignant lesions and compared model-independent and model-dependent methods of data analysis. MethodsWe retrospectively reviewed dynamic contrast-enhanced MRI studies of 37 enhancing orbital and anterior visual pathway lesions. The data were processed using model-independent analysis and model-dependent analysis using a 2-compartment pharmacokinetic model. The time-signal intensity curve and semiquantitative parameters from the model-independent method (area under the curve [AUC] after the initial 60, 90, and 120 s; time to peak; maximum signal enhancement ratio; maximum slope of increase; and washout ratio) and the quantitative parameters from the model-dependent method (Ktrans, kep, and ve) were derived for comparison with pathologic diagnoses. ResultsThe time-signal intensity curves demonstrated different perfusion characteristics and were classified into 4 types. All the lesions that demonstrated curve types 1 and 4 were benign, while type 3 lesions were significantly associated with malignancy (P = 0.001). AUC60, AUC90, AUC120, and kep were significantly lower in benign lesions than in malignant lesions (P = 0.020, 0.018, 0.015, and 0.018, respectively). Receiver operating characteristic analysis indicated that AUC120 yielded the best diagnostic accuracy (area under the curve, 0.80; 95% CI, 0.64–0.96) in differentiating between benign and malignant lesions. ConclusionsDynamic contrast-enhanced MRI is useful in evaluating orbital and anterior visual pathway lesions. The model-independent analysis method is equivalent to the model-dependent method in differentiating benign from malignant lesions.