Prevalence, recovery and phenotype of dysphagia in patients with ischaemic cerebellar stroke.

BACKGROUND AND PURPOSE: Swallowing is a complex task, moderated by a sophisticated bilateral network including multiple supratentorial regions, the brainstem and the cerebellum. To date, conflicting data exist about whether focal lesions to the cerebellum are associated with dysphagia. Therefore, the aim of the study was to evaluate dysphagia prevalence, recovery and dysphagia pattern in patients with ischaemic cerebellar stroke. METHODS: A retrospective analysis of patients consecutively admitted to an academic stroke centre with ischaemic stroke found only in the cerebellum was performed. The presence of dysphagia was the primary end-point and was assessed by a speech-language pathologist, according to defined criteria. Dysphagia pattern was evaluated by analysing the videos of the flexible endoscopic evaluation of swallowing. Brain imaging was used to identify lesion size and location associated with dysphagia. RESULTS: Between January 2016 and December 2021, 102 patients (35.3% female) with a mean age of 52.8 ± 17.3 years were included. Thirteen (12.7%) patients presented with dysphagia. The most frequently observed flexible endoscopic evaluation of swallowing phenotype was premature spillage (n = 7; 58.3%), whilst significant residues or aspiration did not occur. One patient died (7.7%); the other patients showed improvement of dysphagia and one patient (7.7%) was discharged with dietary restrictions. CONCLUSIONS: Although the involvement of the cerebellum in deglutition has become increasingly evident, isolated lesions to the cerebellum are less likely to cause clinically relevant and persisting dysphagia compared to other brain regions. The observed dysphagia pattern shows a lack of coordination and control, resulting in premature spillage or fragmented bolus transfer in some patients.

Abusive head trauma: experience improves diagnosis.

PURPOSE: The diagnosis of abusive head trauma (AHT) is complex and neuroimaging plays a crucial role. Our goal was to determine whether non-neuroradiologists with standard neuroradiology knowledge perform as well as neuroradiologists with experience in pediatric neuroimaging in interpreting MRI in cases of presumptive AHT (pAHT). METHODS: Twenty children were retrospectively evaluated. Patients had been diagnosed with pAHT (6 patients), non-abusive head trauma-NAHT (5 patients), metabolic diseases (3 patients), and benign enlargement of the subarachnoid spaces (BESS) (6 patients). The MRI was assessed blindly, i.e., no clinical history was given to the 3 non-neuroradiologists and 3 neuroradiologists from 2 different institutions. RESULTS: Blindly, neuroradiologists demonstrated higher levels of sensitivity and positive predictive value in the diagnosis of pAHT (89%) than non-neuroradiologists (50%). Neuroradiologists chose correctly pAHT as the most probable diagnosis 16 out of 18 times; in contrast, non-neuroradiologists only chose 9 out of 18 times. In our series, the foremost important misdiagnosis for pAHT was NAHT (neuroradiologists twice and non-neuroradiologists 5 times). Only victims of motor vehicle accidents were blindly misdiagnosed as pAHT. No usual household NAHT was not misdiagnosed as pAHT. Neuroradiologists correctly ruled out pAHT in all cases of metabolic diseases and BESS. CONCLUSION: MRI in cases of suspected AHT should be evaluated by neuroradiologists with experience in pediatric neuroimaging. Neuroradiologists looked beyond the subdural hemorrhage (SDH) and were more precise in the assessment of pAHT and its differential diagnosis than non-neuroradiologists were. It seems that non-neuroradiologists mainly assess whether or not a pAHT is present depending on the presence or absence of SDH.

Optimization of image quality and radiation dose using different cone-beam CT exposure parameters.

PURPOSE: To investigate and optimize the impact of different exposure parameters on image quality and radiation dose for a latest generation orthopedic cone-beam CT system. MATERIALS AND METHODS: 110 consecutive scans of the same cadaver forearm were performed before and after the insertion of a distal radius plate on the palmar radius to achieve highest intra-individual comparability. All scans were conducted on a latest generation cone-beam CT scanner (Carestream OnSight 3D Extremity System, Carestream Health, Rochester, NY, USA). Extremity imaging was performed using different combinations of tube voltage (kV) and tube current - exposure time product (mAs). Radiation dose (DLP and CTDIVOL) was recorded to widely varying combinations. Subjective and objective image quality analysis included a blinded evaluation by five different readers independently using 5-point-Likert scales. RESULTS: Highest radiation dose was achieved using the manufacturers' suggested standard protocol (90-kV and 5.0 mAs with DLP of 111.91 mGy*cm and CTDIVOL of 4.49 mGy), while 70-kV and 2.0 mAs provided the most dose reduction with DLP of 20.34 mGy*cm and CTDIVOL of 0.79 mGy. Regarding subjective image quality, higher tube voltage improved depiction of cortical bone (p ≤ 0.038) and cancellous bone (p ≤ 0.001) as well as overall image quality (p ≤ 0.027). Changes of the tube current - exposure time product did not show significant alterations of image quality (p ≥ 0.063). After plate insertion, only the subjective overall image quality showed reduced subjective perception (p < 0.001). Between the different scan protocols, no relevant changes were observed in the objective image quality analysis (SNR: p ≥ 0.125; CNR: p ≥ 0.086). However, presence of osteosynthesis significantly lowered the mean SNR and CNR (p < 0.001). CONCLUSION: Even with lowest exposure settings, orthopedic extremity CBCT revealed good overall image quality. The best result regarding subjective image quality was achieved with 85-kV / 4.7 mAs with a dose reduction of 18,9% compared to the manufacturer's recommended protocol (90-kV and 5.0 mAs).

Evaluation of Radiation Dose and Image Quality using High-Pitch 70-kV Chest CT in Immunosuppressed Patients. / Evaluation der Strahlendosis und Bildqualität von High-Pitch-70-kV-CT-Untersuchungen des Thorax bei immunsupprimierten Patienten.

PURPOSE: The aim of the study was to evaluate high-pitch 70-kV CT examinations of the thorax in immunosuppressed patients regarding radiation dose and image quality in comparison with 120-kV acquisition. MATERIALS AND METHODS: The image data from 40 patients (14 women and 26 men; mean age: 40.9 ±â€Š15.4 years) who received high-pitch 70-kV CT chest examinations were retrospectively included in this study. A control group (n = 40), matched by age, gender, BMI, and clinical inclusion criteria, had undergone standard 120-kV chest CT imaging. All CT scans were performed on a third-generation dual-source CT unit. For an evaluation of the radiation dose, the CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED), and size-specific dose estimates (SSDE) were analyzed in each group. The objective image quality was evaluated using signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Three blinded and independent radiologists evaluated subjective image quality and diagnostic confidence using 5-point Likert scales. RESULTS: The mean dose parameters were significantly lower for high-pitch 70-kV CT examinations (CTDIvol, 2.9 ±â€Š0.9 mGy; DLP, 99.9 ±â€Š31.0 mGyxcm; ED, 1.5 ±â€Š0.6 mSv; SSDE, 3.8 ±â€Š1.2 mGy) compared to standard 120-kV CT imaging (CTDIvol, 8.8 ±â€Š3.7mGy; DLP, 296.6 ±â€Š119.3 mGyxcm; ED, 4.4 ±â€Š2.1 mSv; SSDE, 11.6 ±â€Š4.4 mGy) (P≤ 0.001). The objective image parameters (SNR: 7.8 ±â€Š2.1 vs. 8.4 ±â€Š1.8; CNR: 7.7 ±â€Š2.4 vs. 8.3 ±â€Š2.8) (P≥ 0.065) and the cumulative subjective image quality (4.5 ±â€Š0.4 vs. 4.7 ±â€Š0.3) (p = 0.052) showed no significant differences between the two protocols. CONCLUSION: High-pitch 70-kV thoracic CT examinations in immunosuppressed patients resulted in a significantly reduced radiation exposure compared to standard 120-kV CT acquisition without a decrease in image quality. KEY POINTS: · Third-generation dual-source CT units enable high-pitch 70-kV CT examinations of the chest.. · High-pitch 70-kV CT examinations show a significantly reduced radiation dose compared to standard 120-kV CT examinations.. · High-pitch 70-kV CT examinations of the chest show comparable objective and subjective image quality.. · Subjectively deteriorated image noise and sharpness of 70-kV CT did not impact diagnostic confidence.. CITATION FORMAT: · Yel I, Martin SS, Wichmann JL et al. Evaluation of Radiation Dose and Image Quality using High-Pitch 70-kV Chest CT in Immunosuppressed Patients . Fortschr Röntgenstr 2019; 191: 122 - 129.

Dynamic Liver Magnetic Resonance Imaging in Free-Breathing: Feasibility of a Cartesian T1-Weighted Acquisition Technique With Compressed Sensing and Additional Self-Navigation Signal for Hard-Gated and Motion-Resolved Reconstruction.

OBJECTIVES: The aim of this study was to assess the feasibility of a free-breathing dynamic liver imaging technique using a prototype Cartesian T1-weighted volumetric interpolated breathhold examination (VIBE) sequence with compressed sensing and simultaneous acquisition of a navigation signal for hard-gated and motion state-resolved reconstruction. MATERIALS AND METHODS: A total of 43 consecutive oncologic patients (mean age, 66 ± 11 years; 44% female) underwent free-breathing dynamic liver imaging for the evaluation of liver metastases from colorectal cancer using a prototype Cartesian VIBE sequence (field of view, 380 × 345 mm; image matrix, 320 × 218; echo time/repetition time, 1.8/3.76 milliseconds; flip angle, 10 degrees; slice thickness, 3.0 mm; acquisition time, 188 seconds) with continuous data sampling and additionally acquired self-navigation signal. Data were iteratively reconstructed using 2 different approaches: first, a hard-gated reconstruction only using data associated to the dominating motion state (CS VIBE, Compressed Sensing VIBE), and second, a motion-resolved reconstruction with 6 different motion states as additional image dimension (XD VIBE, eXtended dimension VIBE). Continuous acquired data were grouped in 16 subsequent time increments with 11.57 seconds each to resolve arterial and venous contrast phases. For image quality assessment, both CS VIBE and XD VIBE were compared with the patient's last staging dynamic liver magnetic resonance imaging including a breathhold (BH) VIBE as reference standard 4.5 ± 1.2 months before. Representative quality parameters including respiratory artifacts were evaluated for arterial and venous phase images independently, retrospectively and blindly by 3 experienced radiologists, with higher scores indicating better examination quality. To assess diagnostic accuracy, same readers evaluated the presence of metastatic lesions for XD VIBE and CS VIBE compared with reference BH examination in a second session. RESULTS: Compared with CS VIBE, XD VIBE showed significantly higher overall image quality for both arterial phase (4.2 ± 0.6 vs 3.8 ± 0.7, P = 0.008) and venous phase (4.7 ± 0.4 vs 4.3 ± 0.7, P < 0.001) imaging. There was no significant difference between XD VIBE and BH VIBE for overall image quality in the venous phase (4.7 ± 0.4 vs 4.8 ± 0.4, P = 0.834), whereas arterial phase images were scored slightly lower for XD VIBE (4.5 ± 0.6 vs 4.2 ± 0.6, P = 0.024). Both XD VIBE and BH VIBE were characterized by a very low level of respiratory artifacts with no significant difference between BH and motion-resolved free-breathing strategy (P = 0.505 for arterial phase; P = 0.496 for venous phase). Compared with CS VIBE, obvious quality improvement could be achieved for the extended XD VIBE reconstruction with significantly reduced motion artifacts for venous phase images (P = 0.007). Generally, arterial phase images were scored slightly lower compared with venous phase images when using the free-breathing protocol. Overall, 98% of all metastatic lesions were identified on XD VIBE images and 92% of all metastases were found on CS VIBE. CONCLUSIONS: Dynamic liver imaging using the proposed free-breathing Cartesian strategy is feasible in oncologic patients with excellent image quality, high respiratory motion robustness, and accurate lesion detection. Overall, XD VIBE was superior to CS VIBE in our study.

Free-breathing dynamic liver examination using a radial 3D T1-weighted gradient echo sequence with moderate undersampling for patients with limited breath-holding capacity.

PURPOSE: To compare free-breathing radial VIBE with moderate undersampling (us-radial-VIBE) with a standard breathhold T1-weighted volumetric interpolated sequence (3D GRE VIBE) in patients unable to suspend respiration during dynamic liver examination. MATERIAL AND METHODS: 23 consecutive patients underwent dynamic liver MR examination using the free-breathing us-radial-VIBE sequence as part of their oncologic follow-up. All patients were eligible for the free-breathing protocol due to severe respiratory artifacts at the planning or precontrast sequences. The us-radial-VIBE acquisitions were compared to the patients last staging liver MRI including a standard breathhold 3D GRE VIBE. For an objective image evaluation, signal intensity (SI), image noise (IN), signal-to-noise ratio (SNR) and contrast-enhancement ratio (CER) were compared. Representative image quality parameters, including typical artifacts were independently, retrospectively and blindly scored by four readers. RESULTS: Us-radial-VIBE had significant lower SNR (p<0.0001) and higher IN (p<0.0001), whereas SI did not differ (p=0.62). Temporal resolution assessed with CER in the arterial phase showed higher values for us-radial-VIBE (p=0.028). Subjective image quality parameters received generally slightly higher scores for 3D GRE VIBE. In a smaller subgroup comprising patients with severe respiratory artifacts also at reference breathhold 3D GRE VIBE examination, us-radial-VIBE showed significantly higher image quality scores. Furthermore, there were generally more severe respiratory artifacts in 3D GRE VIBE, whereas streaking was characteristic in almost all us-radial-VIBE acquisitions but did not affect diagnostic validity. CONCLUSION: Free-breathing dynamic liver imaging using us-radial-VIBE delivers accurate temporal resolution, low motion artifact susceptibility and good image quality and represents a promising alternative in patients unable to suspend respiration.