Amide Proton Transfer Contrast Distribution in Different Brain Regions in Young Healthy Subjects

ObjectivesTo define normal signal intensity values of amide proton transfer-weighted (APTw) magnetic resonance (MR) imaging in different brain regions.Materials and MethodsTwenty healthy subjects (9 females, mean age 29 years, range 19 – 37 years) underwent MR imaging at 3 Tesla. 3D APTw (RF saturation B1,rms = 2 μT, duration 2 s, 100% duty cycle) and 2D T2-weighted turbo spin echo (TSE) images were acquired. Postprocessing (image fusion, ROI measurements of APTw intensity values in 22 different brain regions) was performed and controlled by two independent neuroradiologists. Values were measured separately for each brain hemisphere. A subject was scanned both in prone and supine position to investigate differences between hemispheres. A mixed model on a 5% significance level was used to assess the effect of gender, brain region and side on APTw intensity values.ResultsMean APTw intensity values in the hippocampus and amygdala varied between 1.13 and 1.57%, in the deep subcortical nuclei (putamen, globus pallidus, head of caudate nucleus, thalamus, red nucleus, substantia nigra) between 0.73 and 1.84%, in the frontal, occipital and parietal cortex between 0.56 and 1.03%; in the insular cortex between 1.11 and 1.15%, in the temporal cortex between 1.22 and 1.37%, in the frontal, occipital and parietal white matter between 0.32 and 0.54% and in the temporal white matter between 0.83 and 0.89%. APTw intensity values were significantly impacted both by brain region (p < 0.001) and by side (p < 0.001), whereby overall values on the left side were higher than on the right side (1.13 vs. 0.9%). Gender did not significantly impact APTw intensity values (p = 0.24). APTw intensity values between the left and the right side were partially reversed after changing the position of one subject from supine to prone.ConclusionWe determined normal baseline APTw intensity values in different anatomical localizations in healthy subjects. APTw intensity values differed both between anatomical regions and between left and right brain hemisphere

Sex and age dependencies of aqueductal cerebrospinal fluid dynamics parameters in healthy subjects

Objectives: To assess the influence of age and sex on 10 cerebrospinal fluid (CSF) flow dynamics parameters measured with an MR phase contrast (PC) sequence within the cerebral aqueduct at the level of the intercollicular sulcus.Materials and Methods: 128 healthy subjects (66 female subjects with a mean age of 52.9 years and 62 male subjects with a mean age of 51.8 years) with a normal Evans index, normal medial temporal atrophy (MTA) score, and without known disorders of the CSF circulation were included in the study. A PC MR sequence on a 3T MR scanner was used. Ten different flow parameters were analyzed using postprocessing software. Ordinal and linear regression models were calculated.Results: The parameters stroke volume (sex: p < 0.001, age: p = 0.003), forward flow volume (sex: p < 0.001, age: p = 0.002), backward flow volume (sex: p < 0.001, age: p = 0.018), absolute stroke volume (sex: p < 0.001, age: p = 0.005), mean flux (sex: p < 0.001, age: p = 0.001), peak velocity (sex: p = 0.009, age: p = 0.0016), and peak pressure gradient (sex: p = 0.029, age: p = 0.028) are significantly influenced by sex and age. The parameters regurgitant fraction, stroke distance, and mean velocity are not significantly influenced by sex and age.Conclusion: CSF flow dynamics parameters measured in the cerebral aqueduct are partly age and sex dependent. For establishment of reliable reference values for clinical use in future studies, the impact of sex and age should be considered and incorporated

Humor in radiological breast cancer screening: a way of improving patient service?

BACKGROUND Breast cancer screening is essential in detecting breast tumors, however, the examination is stressful. In this study we analyzed whether humor enhances patient satisfaction. METHODS In this prospective randomized study 226 patients undergoing routine breast cancer screening at a single center during October 2020 to July 2021 were included. One hundred thirty-two were eligible for the study. Group 1 (66 patients) received an examination with humorous intervention, group 2 (66 patients) had a standard breast examination. In the humor group, the regular business card was replaced by a self-painted, humorous business card, which was handed to the patient at the beginning of the examination. Afterwards, patients were interviewed with a standardized questionnaire. Scores between the two study groups were compared with the Mann-Whitney U test or Fisher's exact test. P-values were adjusted with the Holm's method. Two-sided p-values < 0.05 were considered significant. RESULTS One hundred thirty-two patients, 131 female and 1 male, (mean age 59 ± 10.6 years) remained in the final study cohort. Patients in the humor group remembered the radiologist's name better (85%/30%, P < .001), appreciated the final discussion with the radiologist more (4.67 ± 0.73-5;[5, 5] vs. 4.24 ± 1.1-5;[4, 5], P = .017), felt the radiologist was more empathetic (4.94 ± 0.24-5;[5, 5] vs.4.59 ± 0.64-5;[4, 5], P < .001), and rated him as a humorous doctor (4.91 ± 0.29-5;[5, 5] vs. 2.26 ± 1.43-1;[1, 4], P < .001). Additionally, patients in the humor group tended to experience less anxiety (p = 0.166) and felt the doctor was more competent (p = 0.094). CONCLUSION Humor during routine breast examinations may improve patient-radiologist relationship because the radiologist is considered more empathetic and competent, patients recall the radiologist's name more easily, and value the final discussion more. TRIAL REGISTRATION We have a general approval from our ethics committee because it is a retrospective survey, the patient lists for the doctors were anonymized and it is a qualitative study, since the clinical processes are part of the daily routine examinations and are used independently of the study. The patients have given their consent to this study and survey

Nine hole peg test and transcranial magnetic stimulation: useful to evaluate dexterity of the hand and disease progression in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with involvement of the upper and lower motor neurons. Since the loss of fine motor skills is one of the earliest signs of ALS, the hypothesis was tested if the nine hole PEG test (NHPT) and transcranial magnet stimulation (TMS) with resting-motor threshold (RMT) could be useful in monitoring disease progression. Methods. We examined 28 ALS patients and 27 age-matched healthy controls. ALS patients and healthy controls underwent the nine hole peg test (NHPT) and TMS with RMT. Measurements in patients were repeated after three and six months. Results. At baseline, the median NHPT durations were 1,4-fold longer (p < 0.001), and TMS scores showed a significant 0.8-fold smaller score in ALS patients compared with healthy controls (p < 0.001). The comparison of three and six months versus baseline revealed significant differences for NHPT durations and ALSFRS-R in patients, whereas TMS scores did not significantly differ in the patients. Conclusion. NHPT seems to be a good tool to evaluate dexterity of the hand and the progression of the disease in ALS patients. TMS RMT to the hand muscles seems to be poorly qualified to evaluate the dexterity of the hand function and the course of the disease

Review and consensus recommendations on clinical APT-weighted imaging approaches at 3T: Application to brain tumors

Amide proton transfer-weighted (APTw) MR imaging shows promise as a biomarker of brain tumor status. Currently used APTw MRI pulse sequences and protocols vary substantially among different institutes, and there are no agreed-on standards in the imaging community. Therefore, the results acquired from different research centers are difficult to compare, which hampers uniform clinical application and interpretation. This paper reviews current clinical APTw imaging approaches and provides a rationale for optimized APTw brain tumor imaging at 3T, including specific recommendations for pulse sequences, acquisition protocols, and data processing methods. We expect that these consensus recommendations will become the first broadly accepted guidelines for APTw imaging of brain tumors on 3 T MRI systems from different vendors. This will allow more medical centers to use the same or comparable APTw MRI techniques for the detection, characterization, and monitoring of brain tumors, enabling multi-center trials in larger patient cohorts and, ultimately, routine clinical use

Ultrafast Intracranial Vessel Imaging With Non-Cartesian Spiral 3-Dimensional Time-of-Flight Magnetic Resonance Angiography at 1.5 T: An In Vitro and Clinical Study in Healthy Volunteers

OBJECTIVES Non-Cartesian spiral magnetic resonance (MR) acquisition may enable higher scan speeds, as the spiral traverses the k-space more efficiently per given time than in Cartesian trajectories. Spiral MR imaging can be implemented in time-of-flight (TOF) MR angiography (MRA) sequences. In this study, we tested the performance of five 3-dimensional TOF MRA sequences for intracranial vessel imaging at 1.5 T with qualitative and quantitative image quality metrics based on in vitro and in vivo measurements. Specifically, 3 novel spiral TOF MRA sequences (spiral-TOFs) and a compressed sensing (CS) technology-accelerated TOF MRA sequence (CS 3.5) were compared with a conventional (criterion standard) parallel imaging-accelerated TOF MRA sequence (SENSE). MATERIALS AND METHODS The SENSE sequence (5:08 minutes) was compared with the CS 3.5 sequence (3:06 minutes) and a spiral-TOF (spiral, 1:32 minutes), all with identical resolutions. In addition, 2 further isotropic spiral-TOFs (spiral 0.8, 2:12 minutes; spiral 0.6, 5:22 minutes) with higher resolution were compared with the SENSE. First, vessel tracking experiments were performed in vitro with a dedicated vascular phantom to determine possible differences in the depiction of cross-sectional areas of vessel segments. For the in vitro tests, an additional 3-dimensional proton density-weighted sequence was added for comparison reasons. Second, 3 readers blinded to sequence details assessed qualitative (16 features) and 2 readers assessed quantitative (contrast-to-noise ratio [CNR], contrast ratio [CR], vessel sharpness, and full width at half maximum edge criterion measurements) image quality based on images acquired from scanning 10 healthy volunteers with all 5 TOF sequences. Scores from quantitative image quality analysis were compared with Kruskal-Wallis, analysis of variance, or Welch's analysis of variance, followed by Dunnett's or Dunnett's T3 post hoc tests. Scores from qualitative image quality analysis were compared with exact binomial tests, and the level of interreader agreement was determined with Krippendorff's alpha. RESULTS Concerning the in vitro tests, there were no significant differences between the 5 TOFs and the proton density-weighted sequence in measuring cross-sectional areas of vessel segments (P = 0.904). As for the in vivo tests, the CS 3.5 exhibited equal qualitative image quality as the SENSE, whereas the 3 spiral-TOFs outperformed the SENSE in several categories (P values from 0.002 to 0.031). Specifically, the spiral 0.8 and 0.6 sequences achieved significantly higher scores in 12 categories. Interreader agreement ranged from poor (alpha = -0.013, visualization of internal carotid artery segment C7) to substantial (alpha = 0.737, number of vessels visible, sagittal). As for the quantitative metrics, the CS 3.5 and all 3 spiral-TOFs presented with significantly worse CNR than the SENSE ([mean ± SD] SENSE 37.48 ± 7.13 vs CS 3.5 31.14 ± 5.97 vs spiral 19.77 ± 1.65 vs spiral 0.8 16.18 ± 2.14 vs spiral 0.6 10.37 ± 1.05). The CR values did not differ significantly between the SENSE and the other TOFs except for the spiral sequence that showed significantly improved CR (SENSE 0.53 ± 0.03 vs spiral 0.56 ± 0.03). As for vessel sharpness, the SENSE was outperformed by all spiral-TOFs (SENSE 0.37 ± 0.03 vs spiral 0.52 ± 0.07 vs spiral 0.8 0.53 ± 0.08 vs spiral 0.6 0.73 ± 0.09), whereas the CS 3.5 performed equally well (SENSE 0.37 ± 0.03 vs CS 3.5 0.37 ± 0.03). Full width at half maximum values did not differ significantly between any TOF. CONCLUSIONS Spiral-TOFs may deliver high-quality intracranial vessel imaging thus matching the performance of conventional parallel imaging-accelerated TOFs (such as the SENSE). Specifically, imaging can be performed at unprecedented scan times as short as 1:32 minutes per sequence (70.12% scan time reduction compared with SENSE). Optionally, spiral imaging may also be used to increase spatial resolution while maintaining the scan time of a Cartesian-based acquisition schema. The CNR was decreased in spiral-TOF images

Common artefacts encountered on images acquired with combined compressed sensing and SENSE

Abstract Various techniques have been proposed which aim at scan time reduction and/or at improved image quality by increasing the spatial resolution. Compressed sensing (CS) takes advantage of the fact that MR images are usually sparse in some transform domains and recovers this sparse representation from undersampled data. CS may be combined with parallel imaging such as sensitivity encoding (SENSE), hereafter referred to as Compressed SENSE, to further accelerate image acquisition since both techniques rely on different ancillary information. In practice, Compressed SENSE may reduce scan times of two-dimensional (2D) and three-dimensional (3D) scans by up to 50% depending on the sequence acquired and it works on 1.5-T or 3-T scanners. Compressed SENSE may be applied to 2D and 3D sequences in various anatomies and image contrasts. Image artefacts (i.e. motion, metal and flow artefacts, susceptibility artefacts) frequently appear on magnetic resonance images. The Compressed SENSE technique may cause special artefacts, which might influence image assessment if they go undetected by imaging readers. Our institution has been using Compressed SENSE for over half a year, both in a neuroradiological setting and for musculoskeletal examinations. So far, three special image artefacts—called the wax-layer artefact, the streaky-linear artefact and the starry-sky artefact—have been encountered and we aim to review these main artefacts appearing in sequences acquired with Compressed SENSE. Teaching Points • Compressed SENSE combines compressed sensing and SENSE technique. • Compressed SENSE permits scan time reduction and increases spatial image resolution. • Images acquired with Compressed SENSE may present with special artefacts. • Knowledge of artefacts is necessary for reliable image assessment

Intraneural hemorrhage in traumatic oculomotor nerve palsy

Isolated traumatic oculomotor nerve palsy without internal ophthalmoplegia is a rare condition after closed head trauma. The nerve strain leads to intraneural edema with nerve swelling on T2-weighted magnetic resonance (MR) images and traumatic disruption of the blood peripheral nerve barrier with contrast enhancement on T1-weighted MR images. In this patient, susceptibility-weighted MR imaging allowed the direct visualization of the intraneural hemorrhage after suspected traumatic diffuse neuronal axonal injury

Amide Proton Transfer Contrast Distribution in Different Brain Regions in Young Healthy Subjects

Objectives: To define normal signal intensity values of amide proton transfer-weighted (APTw) magnetic resonance (MR) imaging in different brain regions. Materials and Methods: Twenty healthy subjects (9 females, mean age 29 years, range 19 – 37 years) underwent MR imaging at 3 Tesla. 3D APTw (RF saturation B1,rms = 2 μT, duration 2 s, 100% duty cycle) and 2D T2-weighted turbo spin echo (TSE) images were acquired. Postprocessing (image fusion, ROI measurements of APTw intensity values in 22 different brain regions) was performed and controlled by two independent neuroradiologists. Values were measured separately for each brain hemisphere. A subject was scanned both in prone and supine position to investigate differences between hemispheres. A mixed model on a 5% significance level was used to assess the effect of gender, brain region and side on APTw intensity values. Results: Mean APTw intensity values in the hippocampus and amygdala varied between 1.13 and 1.57%, in the deep subcortical nuclei (putamen, globus pallidus, head of caudate nucleus, thalamus, red nucleus, substantia nigra) between 0.73 and 1.84%, in the frontal, occipital and parietal cortex between 0.56 and 1.03%; in the insular cortex between 1.11 and 1.15%, in the temporal cortex between 1.22 and 1.37%, in the frontal, occipital and parietal white matter between 0.32 and 0.54% and in the temporal white matter between 0.83 and 0.89%. APTw intensity values were significantly impacted both by brain region (p < 0.001) and by side (p < 0.001), whereby overall values on the left side were higher than on the right side (1.13 vs. 0.9%). Gender did not significantly impact APTw intensity values (p = 0.24). APTw intensity values between the left and the right side were partially reversed after changing the position of one subject from supine to prone. Conclusion: We determined normal baseline APTw intensity values in different anatomical localizations in healthy subjects. APTw intensity values differed both between anatomical regions and between left and right brain hemisphere