Potential Clinical Utility of a Free-Breathing Cardiac Magnetic Resonance Imaging Protocol at 3T

Background It is hard for patients with impaired breath-holding (BH) capacity to receive conventional cardiac magnetic resonance (CCMR) imaging. Purpose To explore the clinical utility of a free-breathing (FB) CMR (FCMR) imaging protocol at 3.0T. Methods 54 selected patients with suspected heart disease were prospectively enrolled. A total of 30 patients with good BH underwent CCMR protocols first and then FCMR imaging protocols. For other 24 patients with bad BH, CCMR protocols were aborted due to limited BH capacity of patients that led to non-diagnostic image quality (IQ), and the study was finished with FCMR protocols. CCMR included segmented cine and late gadolinium enhancement (LGE) images acquired under BH. FCMR included compressed sensing (CS) accelerated, single-shot cine and motion-corrected (MOCO) single-shot LGE images acquired under FB. IQ of both protocols was evaluated based on a five-point Likert scale. The imaging time, the left ventricular function(LVF), scar presence/absence, and IQ were compared between CCMR and FCMR protocols. Results The acquisition times of the FB-CS-cine SAX (25 ± 5s), FB-CS-cine LAX(8 ± 2s), and FB-MOCO-LGE SAX (120 ± 19s), FB-MOCO-LGE LAX(37 ± 6s) were significantly shorter than these with BH-cine SAX (240 ± 13s), BH-cine LAX (75 ± 16s) and BH-LGE SAX(331 ± 29s), BH-LGE LAX(100 ± 9s) respectively (all P<0.001). For 30 patients that finished both CCMR and FCMR protocols, it was shown that IQ in FB-CS-cine is lower than BH-cine [4 (3-4) vs. 5 (4-5) , P <0.001], however FB-MOCO-LGE is better than BH-LGE [5 (4-5) vs. 3 (3-4), P <0.001]. No significant differences were found in LVF, and LGE presence(all P>0.05). The 24 patients with limited BH capabilities had inconclusive results with the CCMR protocol, but definitive diagnoses were made with the FCMR protocol. Conclusions FCMR could be used as an alternative scanning protocol in patients with BH impairments, making CMR imaging more widely available also for vulnerable patients.

Functional connectivity abnormalities of the long-axis hippocampal subregions in schizophrenia during episodic memory

Past evidence suggests that hippocampal subregions, namely the anterior and posterior parts, may be engaged in distinct networks underlying the memory functions which may be altered in patients with schizophrenia. However, of the very few studies that have investigated the hippocampal longitudinal axis subdivisions functional connectivity in patients with schizophrenia, the majority was based on resting-state data, and yet, none aimed to examine these during an episodic memory task. A total of 41 patients with schizophrenia and 45 healthy controls were recruited for a magnetic resonance imaging protocol in which they performed an explicit memory task. Seed-based functional connectivity analysis was employed to assess connectivity abnormalities between hippocampal subregions and voxel-wise connectivity targets in patients with schizophrenia. We observed a significantly reduced connectivity between the posterior hippocampus and regions from the default mode network, but increased connectivity with the primary visual cortex, in patients with schizophrenia compared to healthy subjects. Increased connectivity between the anterior hippocampus and anterior temporal regions also characterized patients with schizophrenia. In the current study, we provided evidence and support for studying hippocampal subdivisions along the longitudinal axis in schizophrenia. Our results suggest that the abnormalities in hippocampal subregions functional connectivity reflect deficits in episodic memory that may be implicated in the pathophysiology of schizophrenia.

Masseter muscle adaptation following orthognathic surgery - Biomodelling analysis - A pilot study

Purpose: This pilot investigation was designed to apply several, newly developed and more sophisticated methods of measuring muscle structure, function and fibre orientation to a situation where adaptation of muscle is pivotal to the success of a therapeutic approach. Materials and Methods: Patients attending the combined orthodontic / orthognathic surgery clinic at the Clitrofa – Centro Médico, Dentário e Cirúrgico, in Trofa - Portugal were screen using Magnetic Resonance Imaging protocol. Ten patients scheduled for a bimaxillary osteotomy involving a combination of maxillary Le Fort I impaction procedure coupled with a sagittal split advancement of the mandible were select to form the study group. An Experimental design used to provide information in relation to masticatory muscle adaptation following orthognathic surgery. The study involved the contribution of two independent examiners that measured the changes in fibre orientation at the different jaw positions using AnatomicsTM software, at three different time moments. A combination of different parametric tests has been used to compare the different experimental variables. Results: Statistical differences have been identified between examiners measurements and between operations. There were no significant differences testing different times. Conclusions: The discrepancies between examiners probably arise from small variations in the experimental methodology used by them. The differences between operations reveal the masseter muscle adaptation following orthognathic surgery. The measurement of “P1 masseter muscle/ Zygomatic bone / process mastoid anterior angle” and “P2 masseter muscle / mandibular angle” can therefore be a valuable tool for controlling the reworking of masseter muscle upon orthognathic surgery.

Asymmetry and Positioning of the Levator Veli Palatini Muscle in Children With Repaired Cleft Palate

Purpose The purpose of this study is to examine the differences in velopharyngeal dimensions as well as levator veli palatini (levator) muscle morphology, positioning, and symmetry of children with repaired cleft palate with velopharyngeal insufficiency (VPI), children with repaired cleft palate with complete velopharyngeal closure, and children with noncleft anatomy. Method Fifteen children ranging in age from 4 to 8 years were recruited for this study. Ten of the participants had a history of repaired cleft palate, half with documented VPI and the other half with velopharyngeal closure. Five participants with noncleft anatomy were matched for age from a normative database. The magnetic resonance imaging protocol, processing methods, and analysis are consistent with that used in previous literature. Results Regarding velopharyngeal dimensions, median values were statistically significantly different between groups for sagittal angle ( p = .031) and effective velopharyngeal ratio ( p = .013). With respect to the levator muscle, median values were statistically significant for average extravelar length ( p = .018), thickness at midline ( p = .021), and thickness between the left and right muscle bundles at the point of insertion into the velum ( p = .037). Remaining measures were not statistically significant. Conclusions The levator muscle is significantly different among these three groups with respect to thickness at midline, extravelar length, and symmetry at the point of insertion into the velum. Sagittal angle and effective velopharyngeal ratio are also significantly different. Participants with repaired cleft palate and VPI displayed the greatest degree of asymmetry. Future research should control for surgical procedure type to determine the impact of surgery on the levator muscle and surrounding velopharyngeal anatomy.